Fundamentals of Ecology

1.018/7.30J Fundamentals of Ecology

Fall 2003

Lecture 1 – Introduction to Ecology READINGS FOR NEXT LECTURE: 

Krebs Chapter 1: Introduction to the Science of Ecology



Redox Handout (please work through the example problems). (H, W)



Vernadskii (1926). The Biosphere. (H, W)



Rowe (1992). Biological Fallacy: Life Equals Organisms. (H, W)



Remmert (1980). Ecology: The Basic Concept. (H, W)

Outline for today: I. II. III. IV. V.

What is ecology? Why study ecology? How to study ecology? Where to study ecology? How will we learn about ecology?

RECITATIONS NEXT WEEK (9/8 and 9/11):

I. What is ecology? origin of word: oikos = oikos = the family household logy = logy = the study of interesting parallel to economy = = management of the household many principles in common – resources allocation, cost-benefit ratios definitions: Haeckel (German zoologist) 1870: “By ecology we mean the body of knowledge concerning the economy of Nature - the investigation of the total relations of the animal to its inorganic and organic environment.” Burdon-Sanderson (1890s): Elevated Ecology to one of the three natural divisions of Biology: Physiology - Morphology – Ecology Andrewartha (1961): “The scientific s cientific study of the distribution and abundance of o f organisms.” Odum (1963): “The structure and function of Nature.” Definition we will use (Krebs 1972): “Ecology is the scientific study of the processes regulating the distribution and abundance of organisms and the interactions among them, and the study of how these organisms in turn mediate the transport and transformation of energy and matter in the biosphere (i.e., the study of the design of ecosystem structure and function).” The goal of ecology is to understand the principles of operation of natural systems and to predict their responses to change. 1

What ecology is not Ecology is not environmentalism, nor “deep ecology.” Ecology is science, based on biological, physical and chemical principles, and should be value-free. Environmentalism advocates for certain actions and policy positions.

II.

Why study ecology?

Curiosity – Curiosity – How does the world around us work? How are we shaped by our surroundings? Responsibility – Responsibility – How do our actions change our environment? How do we minimize the detrimental effects of our actions? Overfishing, habitat destruction, loss of biodiversity, climate change. Nature as a guide – guide – The living world has been around much longer than we have and has solved many problems with creative solutions. Ecological systems are models for sustainability. How can we feed our growing population? Where will we live? Sustainability – Sustainability – a property of human society in which ecosystems (including humans) are managed such that the conditions supporting present day life on earth can continue. Ecology helps us understand complex problems. Examples: Cane toads in Australia Feral pigs in Hawai’i Nile Perch in Lake Victoria Wolves in Yellowstone

III. How to study ecology? What kinds of experiments do ecologists perform? Observations – Observations – Go into the field and see what’s happening Microcosms – Microcosms – Isolate a portion, limit factors, manipulate conditions. Mathematical models – models – Describe ecosystems interactions as equations.

Connections to other disciplines :

Genetics (7) Hydrology (1)

Physiology (5,7)

ECOLOGY Biochemistry (5,7)

Behavior (7,9)

adapted from Elements of Ecology , R.L. Smith and th T.M. Smith, 4 Ed.

Atmospheric sciences (1,12)

Geology 12

2

IV. Where to study ecology? Organism

(Tiss issues)

Orga rganell nelle e

Mole olecule ule

Ato Atom

Population: Population: Group of interacting and interbreeding organisms.

Community: Community: Different populations living together and interacting. Populations can interact as competitors, predator and prey, or symbiotically. Ecosystem: Organisms and their physical and chemical environments together in a particular area. “The smallest units that can sustain life in isolation from all but atmospheric surroundings.” Biome: Biome: Large scale areas of similar vegetation and climatic characteristics.

Biosphere: Biosphere: Thin film on the surface of the Earth in which all life exists, the union of all of the ecosystems. This is a highly ordered system, held together by the energy of the sun.

When is an organism not an organism? Populations are shaped by their abiotic surroundings, and, in turn, change their abiotic surroundings. For example, O2 in atmosphere from photosynthesis. Others?

These levels of organization do not exist in isolation. There are feedbacks between the largest and smallest scales. Interactions among different levels lead to emergent properties. Principle of hierarchical control (Odum): “As components combine to produce larger functional wholes in hierarchical series, new properties emerge. That is, one cannot explain all the properties at one level from an understanding of the components at the one below.”

V. How will we learn about ecology? Start with energy flows At the individual level, how do organisms “make a living”? At the ecosystem level, how does energy move around? Move on to nutrients How does nutrient availability limit organism growth? On an ecosystem and global scale, how do organisms fit in to global nutrient cycles? Then focus on populations and communities Numerical models of the growth of individual populations Then apply these to model competition between populations for the same resources Metrics of species diversity and responses of communities to changes 3

Study questions • •

• • • •

•

•

Give an example of organisms modifying their surroundings (not mentioned in class). What is the relationship between ecology and environmentalism? Where does Remmert see ecology fitting in to broader societal problems? Why does Remmert call green plants “the first great polluters of the environment”? What is an invasive species? Why do they pose such a serious problem for ecologists? Give an example of an ecosystem, and explain what the associated community would consist of. What kinds of experiments do ecologists perform? What are the advantages and disadvantages of each? According to Vernadskii, in what ways does lif e change the surface of the earth. If all forms of life became extinct, what would happen? What does he mean by “the biosphere is the creation of the sun?” and “Under the thermodynamic conditions of the biosphere, water is a powerful chemical agent...” but on a dead Earth, water is “...a compound of weak chemical activity?” Rowe’s “Biological Fallacy” calls in to question using an organism-level perspective on life. Describe how energy flows would look different if you were a) inside a cell or b) in a space ship looking down on earth. Without prior knowledge, what would you call life?

4


Fall 2003

Lecture 2– Carbon and Energy Transformations READINGS FOR NEXT LECTURE: 

Krebs Chapter 25: Ecosystem Metabolism I: Primary Productivity



Luria. 1975. Overview of photosynthesis. (H, W)



Stowe, S. 2003. When swans inspire not a ballet, but a battle. NY Times. September 3. (H,W)



Kaiser, J. 1995. Can deep bacteria live on nothing but rocks and water? Science. 270:377. (L)



Stevens, TO and JP McKinley. 1995. Lithoautotrophic microbial ecosystems in deep basalt aquifers. Science. 270: 450. (L)



Pace, N. 1997. A molecular view of microbial diversity and the biosphere. Science. 276:734. (L)



Newman, DK and JF Banfield. 2002. Geomicrobiology: How molecular-scale interactions underpin biogeochemical systems. Science. 296:1071. (L)



Sarbu, S et al . 1996. A chemoautotrophically-based cave ecosystem. Science. 272:1953. (L)

“Nature has put itself the problem of how to catch in flight light streaming to earth and to store the most elusive of all powers in rigid form.” Mayer, 1842, discovered law of conservation of energy Outline for today: I. Evolution II. Autotrophs A. Photosynthesis B. Bacterial photosynthesis C. Chemosynthesis III. Heterotrophs A. Aerobic respiration B. Fermentation C. Anaerobic respiration Main question: How do organisms obtain carbon and energy needed to grow and function?

I. Evolution Old view of the world: 5 Kingdoms. Development of new perspective on life. Novel genetic identification techniques (C Woese in the 1970s) “Tree of Life” with 3 Domains: Eubacteria, Archaea, Eukaryotes Hydrothermal vents and hot springs Genotypic not phenotypic classifications

Universal phylogenetic tree based on SSU rRNA sequences Sixty-four rRNA sequences representative of all known phylogenetic domains were aligned, and a tree was produced using FASTDNAML (43, 52). That tree was modified, resulting in the composite one shown, by trimming lineages and adjusting branch points to incorporate results of other analyses. The scale bar corresponds to 0.1 changes per nucleotide. (Pace, N. 1997. Science. 276:734-740)

0

t n e s 1 e r p e r o f e b s r 2 a e y f o s n o 3 i l l i B

Today: Release of fossil carbon

Dinosaurs

21%

Metazoans

Modern eukaryotes Development of ozone shield

Oxygenic phototrophs (cyanobacteria) Prokaryotes

n i g i r s o d l e a b i r t s d e e r r R e T

10%

01% 00.1% Archaebacteria

n s o r n e n i o i i n t i g d r i a e a r d o r M n m a o f B

Eukaryotes

Anoxygenic phototrophs (photosynthetic bacteria)

Eubacteria

Origin of life – 4

20%

l a i r u b n o b r a C

% O2 in atmosphere

3.8 billion years ago

Chemical evolution Photochemical synthesis

Formation of Earth 4.5 billion years ago Figure 2. Adapted from Brock and Madigan, Biology of Microorganisms. Major landmarks in biological evolution.

2

Basic picture of life: “CH2O” and O2

Heterotrophs “nourished from others”

Autotrophs “self-nourishers”

CO2 and H2O II. Autotrophs These “self-nourishers” get their energy from the sun (photoautotrophs) or from reduced inorganic compounds (chemoautotrophs), and they get their carbon from CO2. These organisms undergo two reactions. The first reaction produces ATP* and NADPH**, which provide stored energy and reducing power. For photosynthetic organisms, this is known as the Hill reaction. The second reaction, the Calvin Cycle, is common to all autotrophs, and uses stored energy and reducing power to convert CO2 to CH2O (sugar).

A. Photosynthesis (aerobic) Who? Plants, cyanobacteria, eukaryotic algae C Source? CO2 Energy Source? Sunlight Electron Donor? H2O Where? In aerobic, light conditions

CO2 + H2O + hν

X

⎯⎯⎯⎯

CH2O + O2

B. Bacterial Photosynthesis (anaerobic) Who? Bacteria (e.g. Purple sulfur bacteria) C Source? CO2 Energy Source? Sunlight Electron Donor? H2S Where? In anaerobic, light conditions

CO2 +2 H2S + hν

X CH2O + 2 S + H2O

⎯⎯⎯⎯

C. Chemosynthesis Who? Chemoautotrophic bacteria, aka chemolithoautotrophs C Source? CO2 3

Energy Source? Reduced inorganic compounds (CH4, NH4, H2S, Fe2+) Electron Donor? Reduced inorganic compounds Where? In microaerobic or anaerobic, dark conditions Sulfur oxidizing bacteria: Methanotrophs: Nitrifying bacteria: Iron oxidizing bacteria:

H2S Æ S Æ SO42 CH4 (methane) Æ CO2 NH4+ Æ NO2- Æ NO3 Fe2+ Æ Fe3+

* ATP = adenosine triphosphate. (ADP = adenosine DI phosphate) ** NADPH = nicotinamide adenine dinucleotide phosphate

III. Heterotrophs These organisms (“nourished by others”) get their energy and carbon from reduced organic compounds. ATP and NADH*** are produced, which can then be used elsewhere in the cells.

A. Aerobic respiration Who? Aerobic eukaryotes and prokaryotes C Source? CH2O Energy Source? CH2O Electron Acceptor? O2 Where? Aerobic conditions These reaction is essentially the reverse of the Calvin cycle. O2 is the final electron acceptor. Plants also carry out this reaction to get energy for their growth and metabolic processes.

CH2O + O2

X

⎯⎯⎯⎯

CO2 + H2O

B. Fermentation Who? Eukaryotes and prokaryotes C Source? CH2O Energy Source? CH2O Electron Acceptor? organic compounds Where? Anaerobic conditions This is only the first part of respiration and results in partial breakdown of glucose. The products are organic acids or alcohols (e.g., lactic acid, ethanol, acetic acid) rather than CO2.

4

C. Anaerobic respiration Who? Prokaryotes only C Source? CH2O Energy Source? CH2O Electron Acceptor? Oxidized inorganic compounds (SO42-, Fe3+, NO3+, etc.) Where? Anaerobic conditions Very similar to aerobic respiration, except that O2 is not the final electron acceptor. Instead, another oxidized compound such as SO42-, NO3-, or CO2 is the final electron acceptor. Iron reducing bacteria: Denitrifying bacteria: Sulfate reducing bacteria: Methanogens:

Fe3+ Æ Fe2+ NO3- Æ NO2NO2- Æ N2 H2S Æ S Æ SO42 CO2 Æ CH4 (methane)

***

NADH = nicotinamide adenine dinucleotide (a relative of NADPH. NADH is used for ATP production, while NADPH is associated with biosynthesis)

Study Questions: •

• • •

•

•

What is a Winogradsky column? What are the light, oxygen and sulfide levels in each layer, and which organisms dominate each layer? What are the energy and carbon sources for each kind of organism? Describe the significance of the discovery of deep-sea hydrothermal vents. Why has Rubisco been called the most important protein on Earth? What is unique about the cave ecosystems described in Sarbu’s article? What are the differences and similarities to hydrothermal vents? Banfield and Newman’s article mentions the benefits of advances in genetic techniques for understanding microbial community structure and the identities of microorganisms. Given what you know about metabolic diversity, why is it so hard to culture most microorganisms in a laboratory? If a lake is covered in algae, how do anoxygenic photosynthetic bacteria, which live underneath the algae, manage to obtain sufficient light to carry out photosynthesis?

5


Fall 2003

Lecture 3 – Primary Productivity READINGS FOR NEXT LECTURE: 

Krebs. Pages 97-102: “Light as a Limiting Factor.”



Broad, WJ. 2003. Deep under the sea, boiling founts of life itself.



oceanic components. 

NY Times .

9/9 (H,W)

Behavior Field, CB et al . 1998. Primary production of the biosphere: Integrating terrestrial and (7,9) Science.

281:237-240. (H,W)

Noble IR and R Dirzo. 1997. Forests as human-dominated ecosystems. 277:522-525.

Science.

Questions for today: How do energy and carbon move through ecosystems? How do terrestrial and aquatic ecosystems vary? What limits their productivity?

Outline: I. Scale II. Definitions A. Terms to describe productivity B. Residence times and turnover rate III. Distribution on the Earth IV. Terrestrial Productivity A. Limiting factors B. Measurement

MOVIE NIGHT: Monday 9/15 @ 7:30pm “Cane Toads”

I. Scale

(A) “Metabolism” of a Cell

(B) “Metabolism ” of a Drop of the Ocean (C) “Metabolism ” of an Ocean

CO2

Solar

ADP NADP

CO2 “CH2O”

ATP H2O NADPH Chloroplast GROWTH O2

DNA Nucleus [“CH2O”] Dissolved Organic Carbon

O2

NADH “CH2O” CO2

ATP NAD

1 mm

CO2

Energy

Biological Work O2 - Motility - Biosynthesis - Transport - Electrical Potential - Light Emission

ADP

Phytoplankton

Animals

700

Plants Remineralized Nutrients

O2

CO2 Recycled Inorganic Nutrients

O2

O2 “[CHO] ” 2

O2

“CH2O”

Mixed Layer

O2

“[CH2O]”

600

100m “CH2O”

Zooplankter Fecal pellets

Inorganic Nutrients N,P,Fe,S etc

CO2 Inorganic Nutrients

O2

Mitochondrion

1 µm

CO2

Inorganic Nutrients 40,000

Deep Sea Sediments Upwelled Inorganic Nutrients

4000m Carbon inventory x1015gC

+

1

II. Definitions A. Terms to describe Productivity gross primary productivity (GPP) = rate of conversion of CO 2 to organic carbon per unit surface area -2

-1

-2

-1

Units: g C m year , or Kcal m year

-1

gross primary production has units of g C year for a lake, forest, field, etc. respiration by autotrophs (R A) = how much energy or carbon is used for plant metabolism net primary production (NPP) = GPP – R A = how much energy or carbon is stored as biomass respiration by heterotrophs (R H) = how much energy or carbon is used for heterotroph metabolism net community production (NCP) = GPP – R A – RH = NPP – RH photosynthetic efficiency (PE) = 100*(incident radiation converted to NPP)/(total incident radiation) n.b. We’re using energy and (reduced) carbon interchangeably. Conversion: 39 kJ per g C

B. Residence times and turnover rates f = flux (mass/area/time). use GPP (how much is entering the system) M = mass (biomass/area) 2

2

Mean residence time (MRT) = M/f = (g/m ) / (g/m /year) = years Fractional turnover (k) = 1 / MRT * 100 = % turning over each year

Study Questions: 1. 2. 3. 4. 5. 6. 7. 8.

What is the difference between net and gross primary productivity? What is the difference between net community productivity and net primary productivity? How would you measure these difference? What regulates primary productivity in terrestrial? How is this reflected in the global distribution of primary production? What is the turnover rate in a forest? What does it signify? How is it measured? What is functionally and physiologically similar about phytoplankton and trees? What is different? How will increases in atmospheric CO2 affect global productivity? Discuss the principles behind remote sensing to terrestrial productivity. What limits the quality of the data? Describe 2 strategies plants have developed to deal with low water availability. According to Noble and Dirzo, human domination of forests extends beyond plantations and actively managed lands. In what other ways do humans alter forest ecosystems, and how do the authors recommend minimizing the detrimental impacts?

2

Adapt ed fro m: B ego n,1996

Comparison of Young and Mature Forests -1

Biomass (kg m ) -2 -1 NPP (g m y ) % mass in Wood Leaves Roots Turnover time (y) Tree age (y) Respiration/GPP

Young 9.7 1060

Mature 58 1300

60 10 30 8.5 40–45 0.80

80 1 19 43.5 150–400 1.00

N ET

Ecosystems (in o rder o f p ro du ct iv it y)

TABL E 23.1 P RIMARY P RODUCTION AND P LANT B IOMASS OF W ORLD E

Area 6 2 (10 km )

Mean net prim ary production per unit area 2 (g/m /yr)

COSYSTEMS

World net primary production 9 (10 mtn/yr)

Mean biomass per unit area 2 (kg/m )

Continental

Tropical rain forest Tropical seasonal forest Temperate evergreen forest Temperate deciduous forest Boreal forest Savanna Cultivated land Woodland and shrubland Temperate grassland Tundra and alpine meadow Desert shrub Rock, ice, sand Swamp and marsh Lake and stream Total continental

17.0 7.5 5.0 7.0 12.0 15.0 14.0 8.0 9.0 8.0 18.0 24.0 2.0 2.5 149.0

2000.0 1500.0 1300.0 1200.0 800.0 700.0 644.0 600.0 500.0 144.0 71.0 3.3 2500.0 500.0 720.0

34.00 11.30 6.40 8.40 9.50 10.40 9.10 4.90 4.40 1.10 1.30 0.09 4.90 1.30 107.09

0.6 1.4 0.4 26.6 332.0 361.0 510.0

2000.0 1800.0 500.0 360.0 127.0 153.0 320.0

1.10 2.40 0.22 9.60 42.00 55.32 162.41

44.00 36.00 36.00 30.00 20.00 4.00 1.10 6.80 1.60 0.67 0.67 0.02 15.00 0.02 12.30

Marine

Algal beds and reefs Estuaries Upwelling zones Co ntinental shelf Open ocean Total marine World total

2.00 1.00 0.02 0.01 0.003 .01 3.62 Source: Smith, 2001.

50

TM 4

Vegetation

40

e c n a t c30 e l f e R

c n i r o e i h t p p r s o o s b m t a A

c n i r o e i h t p p r s o o s b m t a A

TM 5

TM 7

TM TM TM 1 2 3

Bare soil

20

10

0.4

0.6

Visible

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

m

Near Infrared Wavelength

A portion of the solar spectrum showing the typical reflectance from soil (-----) and leaf (- - - - ) surfaces and the portions of the spectrum that are measured by the LAND-SAT satellite. Adap ted fr om : Sc hlesi ng er, 1997.

9 8 7 3 M T / 4 M T

e c n 6 a t c e l f 5 e r

y=1.92 x

(0.583)

R2 = 0.91

d 4 e r / r i r 3 a e N 2

1 0

2

4

6

8

10

12

14

16

18

Leaf area index (m2/m2) Adap ted fr om: Sch lesi nger , 1997.

1500

n o i t c 1000 u ) d 1 o r r p y 2 y r a m g m ( i r 500 p t e N

0

5

10

15

20

LAI NPP is directly related to leaf-area index (LAI) for forests in the northwestern United States

Adap ted fr om: Smi th, 2001.

2

) m/ g( r a e y r e p d n u or g e v o b a yt i vi t c u d or p t e N

3000

2000

1000

0

200 400 600 800 1000 1200 Actual evapotranspiration (mm)

Adapted from Krebs

700 ) 1 s 1 -

g

600

Desert herbs Old field herbs Deciduous chaparral shrubs Evergreen shrubs and trees + South African shrubs x

x

x

500

2

O C l o m n ( P P N

x

x

x

400

x

x

x

x

x x

x

x

x

x

x

x

300

x

200 100 0

0

++ + + +

1.0

2.0

3.0

Leaf nitrogen (mmol g-1)

4.0

Terrestrial NPP Co-opted by Humans Source Cultivated Land

NPP Co-opted (Pg) 15.0

Grazing Land Converted Pastures

9.8

Consumed on natural grazing lands

0.8

Burned on Natural Grazing Lands

1.0

Subtotal

11.6

Forest Land Killed during harvest

1.3

Shifting Cultivation

6.1

Land Clearing

2.4

Forest plantation productivity

1.6

Forest harvests

2.2

Subtotal

13.6

Human Occupied Areas

0.4

Total Terrestrial NPP Co-opted

40.6

Total Terrestrial NPP

132.1

Percent Co-opted

30.7% Source: Vitousek at al. 1986 Bioscience 36:368


Fall 2003

Lecture 4 – Primary Productivity in Aquatic Ecosystems READINGS FOR NEXT LECTURE: Oceanus.



Chisholm, SW. 1992. What limits phytoplankton growth?

35:36-46. (H,W)



Falkowski, PG. 2002. The ocean’s invisible forest.



Raloff, J. 2003. Zebra mussels to the rescue.



Perkins, S. 2003. Slow turnover: Warming trend affects African ecosystem. News . 163:404. (H)

Scientific American .

Science News.

287:38-45. (H,W)

163:365. (H) Science

Outline for Today: I. Review Global Distribution II. Measurement techniques III. Limiting factors for freshwater and marine systems A. Light B. Nutrients 1. Distribution and availability 2. Biological requirements (next class)

Study Questions 1. Explain why light tends to be more limiting in freshwater or coastal systems than in the open ocean. 2. Explain the concept of a limiting nutrient. How would you design an experiment to determine which nutrient is limiting in a particular system? 3. What are the challenges associated with using uptake of 14CO2 to measure primary productivity? 4. Why are phytoplankton so much more productive (on the basis of biomass) than land-based plants? Approximately how much do phytoplankton and land-based plants contribute to global primary productivity? 5. Why did scientists used to think that phosphorus, rather than nitrogen, should be the limiting nutrient in oceans? Why is nitrogen often the limiting nutrient instead? And what role does Fe play in nitrogen limitation in oceans? 6. Both Chisholm and Falkowski explain how adding iron to the world’s oceans may enhance their primary productivity, but caution against taking drastic actions on a large scale. Why would the addition of iron enhance productivity? Why might this not be a panacea for elevated atmospheric CO2 levels?

Aquatic ecosystem

R A

GPP

RH

phytoplankton

200m

NPP

zooplankton bacteria fish

Thermocline

3000m

NCP

About 15% NPP falls below the thermocline. Less than 1% makes it to the sea floor

Relative Light Intensity (I/I o) 0

0.2

0.4

0.6

0.8

0

20

) m ( Z h t p e D

k = 0.1

40 k = 0.02

60

dI/dt = -kZ I=Ioe-kZ

80

100

1

Io

Photosynthesis as a function of depth for 3 kinds of lakes

Rate of Photosynthesis 0

20

40

Rate of Photosynthesis

60

0

0

2.5

5


7.5 10

0

0

0.1

0.2


0.3

0

0

0

10

10

1 10

) m ( h t2 p e D

20

) m ( h t p e D

20

20

) m ( h t30 p e D

) m ( h t30 p e D

40

40

3 Eutrophic (Clear Lake) 4

Photoinhibition (Castle Lake) 30

50

Oligotrophic (Lake Tahoe)

60

data modified from Krebs Figure 25.5

50 60

20

40

60

North Pacific Central Gyre

Temperature (o C)

10 0

15

20

Nitrate ( m/L)

Phosphate ( m/L)

25 0 0.2 0.4 0.6 0.8

0

3

6

9 12

Chlorophyll ( m/L)

Primary prod uction (mgC/m 3/half-day expt.)

0 0.1 0.2 0.3 0

2

4

6

8

) 100 m(

th p e 200 D

1% Light level

Zc

300

Adapted from: Krebs Figure 25.7

Thermal stratification in lakes

Nutrients

h t p e D

Temp

Wind Epilimnion (well-mixed, nutrient-poor) Thermocline

Hypolimnion (often O2 depleted nutrient-rich)

But, lakes don’t usually look this way year-round…


Fall 2003

Lecture 5 – Limiting Nutrients and Redfield Ratio READINGS FOR NEXT LECTURE: 

Krebs. Chapter 26. “Ecosystem Metabolism II: Secondary Production”



Nemani RR et al . 2003. Climate-driven increases in global terrestrial net primary production from 1982 to 1999. Science. Science. 300:1560-3. 300:1560-3. (H,W)

REMINDER:

From last class: A few more thoughts on terrestrial primary productivity product ivity

Problem Set 1 Due next Tuesday during lecture. No late problem sets please!

How to integrate all the aspects we talked about? While one factor may dominate, many factors involved:

NPP = f(NPP max, PAR, LAI, T, CO 2, H2O, NA) Where:

NPPmax PAR LAI T [CO2] H2O NA

= maximum for given ecosystem/vegetation type = photosynthetically active radiation = leaf area index = temperature = atmospheric CO2 concentration = soil moisture = index of nutrient availability

How does climate change affect each of these parameters? For instance, atmospheric CO 2 . If [CO2 ] continues to increase, will this increase global NPP? GPP? Some things to consider: Experiments have shown increases in plant biomass with increased atmospheric CO2. Over the past 100 years, the annual rings of tree trunks have not gotten thicker. Leaves from olive branches in King Tut’s tomb have a higher density of stomates than leaves of olive trees in modern-day Egypt. Other studies have shown decreased stomatal density since the Industrial Revolution. What does this mean for water use efficiency? Productivity? If global temperatures temperatures increase 1ºC, or 3ºC, how will this change global NPP? GPP? Consider: Effect of higher temperature on plants, on animals, and on bacteria that feed on detritus. Effect of higher temperatures +/or higher CO2 on the distribution of C3 vs. C4 plants. What is a limiting factor? On what time scale? Limiting for whom?

Limiti Lim iting ng nutrient nut rient analogy nalogy:: Bakin Baking g cookie cook ies s Recipe: 3 cups flour

0.5 cup eggs

2 cups sugar

0.1 cup baking soda

1 cup butter

Questions:  If you start with equal equal amounts amounts of all ingredients, ingredients, which one one is the limiting? • If someone someone brings brings you you more of that that ingredient, ingredient, which ingredient ingredient will now be limiting? • If you start with 60 cups of flour, 50 50 cups of sugar, 10 cups of butter, 10 cups of eggs and 2 cups of baking soda, which ingredient will be limiting?

Canadi Canadian an Research Research and Develo Developm pment ent Magazine Magazine 1970: 1970: “Has the international joint commission…been a party to what may prove to have been the most incredible scientific/political hoax in the history of Canadian and American Relations? What hoax? Do you believe phosphates phosphates are the key nutrient in the process of eutrophication? You are wrong! You have hung phosphates without a fair trial.”

Proct ro ctor or and Gambl Gamble: e: “The problem problem of man-caused man-caused eutrophi eutrophicatio cation n is the most complex subject in our world. It truly encompasses the ‘myste ‘mystery ry of life life on earth earth.’ .’ Thus Thus we are are attemp attemptin ting g to unders understan tand d and answer answer the the questio questions: ns: Why do plant plants s grow? grow? How can we retard or stop their growth?”

Northweste Northwestern rn Ontario Ontario – Experimen Experimental tal Lake Lake 226

N + C add added ed

N + C + P added Image courtesy of Oceans and Fisheries, Canada. http://www.dfo-mpo.gc.ca/home-accueil_e.htm Note: Note: image image usage policy: policy: http://www http://www.dfo-mpo.gc. .dfo-mpo.gc.ca/copyright/cop ca/copyright/copyright_e.htm yright_e.htm

Schindler

September 4, 1973

Pollution and Recovery in Lake Washington

Adapted from Krebs Figure 23.24 Source: Edmondson,1991 (Figure 1.8)

Adapted from Krebs Figure 25.14

Marine phytoplankton samples n 0.25 o i e t t i a d 0.20 r d h a t t w n 0.15 o e r i r g t u 0.10 n i n e g g n 0.05 n i a w h o 0.00 l C l o F -0.05

Nitrogen

Iron

Silica

Phosphorous

Adapted from Krebs Figure 25.9


Fall 2003

Lecture 6 – Introduction to Secondary Productivity READINGS FOR NEXT LECTURE: 

Krebs. Chapter 23 pages 463-469. “Food Chains and Trophic Levels”



Guterl, F. 2003. Troubled seas: Ninety percent of the big fish have already been caught. Newsweek . July 14 edition, p 46. (H,W)



Pauly D and V Christensen. 1995. Primary production required required to sustain global fisheries. Nature. 374:213-4. 374:213-4. (H,W)

REMINDER: Pre-proposal due Thursday! No late proposals!

MOVIE NIGHT: Re-showing of Cane Toads Thursday, 8pm Food provided

The last few lectures, we have focused on primary productivity. As we saw previously, autotrophs are able to capture 1-2% of the incoming solar radiation. We are now going to explore what happens to the energy stored in autotrophic biomass. Secondary productivity is productivity is defined as the rate of biomass accumulation by heterotrophs (herbivores, carnivores and detritivores).

For trophic level n:

Rn An

In

Pn

Pn-1 Fn NU = not used

Dead organic matter compartment of decomposer system

biomass

biomass

Pn-1 = Productivity at trophic level n-1 NU = Productivity from trophic level n-1 not used by used by trophic level n In

= Amount of energy ingested

Fn

= Amount of energy lost as fecal matter fecal matter (but available to detritivores)

An

= Amount of energy assimilated (i.e. available for metabolism)

Rn

= Amount of energy lost lost to respiration

Pn

= Productivity of trophic level n (evident as growth and reproduction)

Study questions 1. 2. 3.

What is the real truth to to Dogbert’s Dogbert’s insights? What is the wasted step? Define a trophic level. level. What are the difficulties difficulties in assigning a species to a single trophic level? level? Describe the difference difference between between exploitation, exploitation, assimilation assimilation and production efficiencies. What are the typical ranges of each of these efficiencies? How do they combine to give an overall ecological ecological efficiency? 4. According to the Newsweek article, article, what are the consequences throughout the marine food web of overfishing of top predator fish? 5. According to Pauly Pauly and Christensen’s article, article, how much of aquatic primary productivity productivity is required required for the amount of fish caught annually? How does this number differ between freshwater freshwater and marine systems? Why does it seem unlikely that humans will be able to harvest much more of the world’s aquatic productivity than is already being harvested?

∆N

: ∆P

20 : 1

Correlation between the concentration of nitrate and phosphate in waters of the Atlantic, Indian, and Pacific Oceans Source: Redfield, 1934

∆C

: ∆N

7: 1

Western Atlantic Source: Redfield, 1934

Units: [NO3]=10-3 millimols per liter [CO3]=10-2 millimols per liter

Western Atlantic Deep Water Samples

∆O2

: ∆N

6: 1

Units: [NO3]=10-3 millimols per liter

Source: Redfield, 1934

REDFIELD HYPOTHESIZED: The proportions of elements in the atmosphere and the sea are controlled by the biogeochemical cycle

NO3 + PO4 + O2

CO2 + PO4 + NO3

Living Organisms + O2

Dead Organisms + O2

Deep Sea

If the elemental composition of the deep ocean water is dictated by the composition of the plant material, the elements should vary in constant proportion from place to place.

100% Saturation

1) O2

Mixed Layer

∆O2

between surface and minimum is ≈`the amount used to oxidize the organic compounds as they settle out of the euphotic zone

O2 Minimum

Depth

2) Measured N:P:C ratios in mid-ocean, surface and deep ocean at various times PO4 NO3

Adapted from Krebs Fig. 23.3

Adapted from: Odum (1972)

From Smith and Smith 2001

Assimilation Efficiencies (A/I) for different types of organisms Herbivore

Carnivore

Microbivore

Saprotroph

Invertebrates

40%

80%

30%

20%

Vertebrates

50%

80%

--

--

From Heal and Mac Lean, 1975

The more similar you are to your food, the more efficient you are at assimilating it

Microbivore = an organism that feeds on microorganisms Saprotroph = a fungus that feeds on detritus

Production Efficiency of Various Animal Groups (ranked in order of increasing efficiency) Group

P /A %

1 Insectivores

0.86

2 Birds

1.29

3 Small Mammal Communities

1.51

4 Other Mammals

3.14

5 Fish and social insects

9.77

6 Non-insect invertebrates

25.0

7 Non-social insects

40.7

Non-insect invertebrates

8 Herbivores

20.8

9 Carnivores

27.6

10 Detritivores

36.2

Non-social insects

11 Herbivores

38.8

12 Detritivores

47.0

13 Carnivores

55.6 Source: Begon (1996)

Courtesy of Eli Meir. Used with permission.

Cod Bottom-dweller but stays relatively close to the surface (within a few hundred meters). •Can reach up to 200 pounds and live 20 - 30 years •Large females can lay 10 million eggs / year •Eats anything that moves and is smaller than mouth

Cod Fishing When Columbus sailed, “1000” Basque ships were fishing Georges Bank and Newfoundland. If 1/2 of these were in Georges Bank and each ship pulled in 20 tons of cod, catch was about 10,000 tons / year. By mid 1500’s, 60% of fish eaten in Europe were cod.

Recipe book of Charles V in France Salt cod is eaten with mustard sauce or with melted fresh butter over it. - Guillaume Tirel, Le Viandier, 1375

Cokkes of Kellyng Take cokkes of kellyng; cut hem smalle. Do hit yn a brothe of fresch fysch or of fresh salmon; bowle hem well. Put to myllke and draw a lyour of bredde to hem with saundres, safferyn & sugure and poudyr of pepyr. Serve hit forth, & otheyr fysch amonge: turbut, pyke, saumon, chopped & hewn. Sesyn hem with venyger & salt. -anonymous manuscript from fifteenth century

How Much Cod Can Be Caught?

Source: Begon (1996)

From Pauly and Christensen See text 546-547 TABLE 2 Global estimates of primary production (PP), of PPR to sustain world fisheries (mean for 1988-1991, net weight), and of the mean trophic levels (TL) of the catches, by ecosystem type PPR (catches +discards) Ecosystem type

Area (106 km2)

PP (gC m-2 yr -1)

Catch (g m-2 yr -1)

Discards (g m-2 yr -1)

TL of the catch

Mean (%)

95% Confidence interval

Open ocean

332.0

103

0.01

0.002

4.0

1.8

1.3-2.7

Upwellings

0.8

973

22.2

3.36

2.8

25.1

17.8-47.9

Tropical Shelves

8.6

310

2.2

0.671

3.3

24.2

16.1-48.8

Non tropical shelves

18.4

310

1.6

0.706

3.5

35.3

19.2-85.5

Coastal/reef systems

2.0

890

8.0

2.51

2.5

8.3

5.4-19.8

Rivers and lakes

2.0

290

4.3

n.a.

3.0

23.6

11.3-62.9

Weighted means (or total)

(363.8)

126

0.26

0.07

2.8

8.0

6.3-14.4

Assimilation Efficiencies (A/I) for different types of organisms Herbiv ore

Carniv ore

Microbiv ore Saprot roph

Invertebrates

40%

80%

30%

20%

Vertebrates

50%

80%

--

--




P /A %

1 Insectivores

0.86

2 Birds

1.29


1.51

4 Other Mammals

3.14


9.77


25.0


40.7


8 Herbivores

20.8

9 Carnivores

27.6

10 Detritivores

36.2

Non-social insects

11 Herbivores

38.8

12 Detritivores

47.0

13 Carnivores


Krebs Fig 26.4

118 Secondary Production Table 6.1 A simple taxonomic-trpohic categorization of heterographic organisms. For each category the characteristic assimiliation (A/C) and growth (P/A) efficiencies are given. (From Heal and Maclean, 1975.) Trophic Function

Herbivore

Carnivore

Microbivore

Saprotoroph

A/C

P/A

A/C

P/A

A/C

P/A

A/C

P/A

Micro organi sms

-

-

-

-

-

-

-

0.40

Inverti brates

0.40

0.40

0.80

0.30

0.30

0.40

0.20

0.40

Vetebr ate homot herms

0.50

0.02

0.80

0.02

-

-

-

-

Vetebr ate heterot herms

0.50

0.10

0.80

0.10

-

-

-

-

0.30 0.25 n 0.20 o i t r o 0.15 p o r P0.10

0.05 0.00 0

2

4 6 Food chain length

8

10

Georges Bank Cod Summary Georges Bank

240 x 120 km in size

Primary productivity

0.9 kg C / m^2 / year

Cod range from trophic level 4 - 6 Transfer efficiencies ~ 10% between trophic levels

What is a guess at sustainable harvest?

Digression - Confidence Limits and Sensitivity Analysis What if energy transfer was 8% instead of 10%? What if less of Georges Bank was suitable habitat? What about other species of bottom fish? Ecological calculations are almost worthless without some measure of the confidence boundaries. Often confidence is assessed through sensitivity analysis - how much difference would mistakes in the input values make to the final result?

Columbus and Cabot In 1492, Columbus sailed the ocean blue. In 1497 John Cabot “discovers” Cape Cod and the Basque fishing vessels In 1500’s there is a cod rush to Massachusetts up to Newfoundland In 1930’s, factory trawlers arrive. In 1960’s, U.S. and Canada increase fishing effort In 1990’s …

NOAA Pub CRD0204

How could catch be at 50,000 tons for years? Productivity

Biomass (Standing Stock)

What happens to system when cod are removed? Trophic cascades Brooks, J. L. and S. I. Dodson, 1965. Predation, body size, and composition of plankton. Science 150: 28-35 Keystone Species Paine, R. T., 1966. Food web complexity and species diversity. diversity. The American American Naturalis Naturalistt 100: 65 - 75.

Question: What controls the diversity of and relative abundance of different species in the intertidal community? First careful observations of the community Transplant different species and find which ones are competitively dominant (dominance hierarchy) Construct food web for predatory species What will happen if one of the species is removed? The answer … is in your next EcoBeaker lab

Wrap-up Ecology can make some general predictions about what might happen to Georges Bank system. Ecology can also make some predictions about whether and how long it might take cod populations to recover. More on the first topic at the end of the course, when discussing communities. More on the second topic in a couple weeks, when talking about population growth.


Fall 2003

Lecture 8 – Introduction to Biogeochemical Cycles READINGS FOR NEXT LECTURE: 

Krebs. Chapter 27. Ecosystem Metabolism III: Nutrient Cycles



Ramanujan K. 2003. Ocean plant life slows down and absorbs less carbon. (H, W) http://www.eurekalert.org/pub_releases/2003-09/nsf c-op1091603.php. accessed 9/16/03



Rietschel M. 2003. Analysis pours cold water on flood theory.

Nature.

425:111. (H,W)

Outline for today:

I. Discussion of pre-proposals II. Biogeochemistry a. Dinosaur question b. Reservoirs and residence times c. Example: methane III. Guest speaker: Anna Mehrotra

Study questions: •

•

•

•

•

What are the major compartments that we consider when drawing biogeochemical cycles? What are some of the major sub-compartments that we also consider? Explain what two factors contribute to a compound having a long residence time in an ocean or in the atmosphere. What are some major differences between the global biogeochemical cycles for P vs C, or CO2 vs. CH4? Wetland, rice patties, termites and cows are major sources of CH4. Why? More of a brain teaser than study question (Hint: think about residence times and fluxes, see water cycle Krebs Figure 28.7)


Fall 2003

Lecture 6 – Introduction to Secondary Productivity READINGS FOR NEXT LECTURE: 

Krebs. Chapter 23 pages 463-469. “Food Chains and Trophic Levels”



Guterl, F. 2003. Troubled seas: Ninety percent of the big fish have already been caught. Newsweek . July 14 edition, p 46. (H,W)



Pauly D and V Christensen. 1995. Primary production required to sustain global fisheries. Nature. 374:213-4. (H,W)

REMINDER: Pre-proposal due Thursday! No late proposals!

MOVIE NIGHT: Re-showing of Cane Toads Thursday, 8pm Food provided

The last few lectures, we have focused on primary productivity. As we saw previously, autotrophs are able to capture 1-2% of the incoming solar radiation. We are now going to explore what happens to the energy stored in autotrophic biomass. Secondary productivity is defined as the rate of biomass accumulation by heterotrophs (herbivores, carnivores and detritivores).

For trophic level n:

Rn An

In

Pn

Pn-1 Fn NU = not used

Dead organic matter compartment of decomposer system

biomass

biomass

Pn-1 = Productivity at trophic level n-1 NU = Productivity from trophic level n-1 not used by trophic level n In

= Amount of energy ingested

Fn

= Amount of energy lost as fecal matter (but available to detritivores)

An

= Amount of energy assimilated (i.e. available for metabolism)

Rn

= Amount of energy lost to respiration

Pn

= Productivity of trophic level n (evident as growth and reproduction)

Study questions 1. 2. 3.

What is the real truth to Dogbert’s insights? What is the wasted step? Define a trophic level. What are the difficulties in assigning a species to a single trophic level? Describe the difference between exploitation, assimilation and production efficiencies. What are the typical ranges of each of these efficiencies? How do they combine to give an overall ecological efficiency? 4. According to the Newsweek article, what are the consequences throughout the marine food web of overfishing of top predator fish? 5. According to Pauly and Christensen’s article, how much of aquatic primary productivity is required for the amount of fish caught annually? How does this number differ between freshwater and marine systems? Why does it seem unlikely that humans will be able to harvest much more of the world’s aquatic productivity than is already being harvested?

∆N

: ∆P

20 : 1

Correlation between the concentration of nitrate and phosphate in waters of the Atlantic, Indian, and Pacific Oceans Source: Redfield, 1934

∆C

: ∆N

7: 1

Western Atlantic Source: Redfield, 1934

Units: [NO3]=10-3 millimols per liter [CO3]=10-2 millimols per liter

Western Atlantic Deep Water Samples

∆O2

: ∆N

6: 1

Units: [NO3]=10-3 millimols per liter

Source: Redfield, 1934

REDFIELD HYPOTHESIZED: The proportions of elements in the atmosphere and the sea are controlled by the biogeochemical cycle

NO3 + PO4 + O2

CO2 + PO4 + NO3

Living Organisms + O2

Dead Organisms + O2

Deep Sea

If the elemental composition of the deep ocean water is dictated by the composition of the plant material, the elements should vary in constant proportion from place to place.

100% Saturation

1) O2

Mixed Layer

∆O2

between surface and minimum is ≈`the amount used to oxidize the organic compounds as they settle out of the euphotic zone

O2 Minimum

Depth

2) Measured N:P:C ratios in mid-ocean, surface and deep ocean at various times PO4 NO3


Adapted from: Odum (1972)

From Smith and Smith 2001

Assimilation Efficiencies (A/I) for different types of organisms Herbivore

Carnivore

Microbivore

Saprotroph

Invertebrates

40%

80%

30%

20%

Vertebrates

50%

80%

--

--



Microbivore = an organism that feeds on microorganisms Saprotroph = a fungus that feeds on detritus


P /A %

1 Insectivores

0.86

2 Birds

1.29


1.51

4 Other Mammals

3.14


9.77


25.0


40.7


8 Herbivores

20.8

9 Carnivores

27.6

10 Detritivores

36.2

Non-social insects

11 Herbivores

38.8

12 Detritivores

47.0

13 Carnivores



Cod Bottom-dweller but stays relatively close to the surface (within a few hundred meters). •Can reach up to 200 pounds and live 20 - 30 years •Large females can lay 10 million eggs / year •Eats anything that moves and is smaller than mouth

Cod Fishing When Columbus sailed, “1000” Basque ships were fishing Georges Bank and Newfoundland. If 1/2 of these were in Georges Bank and each ship pulled in 20 tons of cod, catch was about 10,000 tons / year. By mid 1500’s, 60% of fish eaten in Europe were cod.

Recipe book of Charles V in France Salt cod is eaten with mustard sauce or with melted fresh butter over it. - Guillaume Tirel, Le Viandier, 1375

Cokkes of Kellyng Take cokkes of kellyng; cut hem smalle. Do hit yn a brothe of fresch fysch or of fresh salmon; bowle hem well. Put to myllke and draw a lyour of bredde to hem with saundres, safferyn & sugure and poudyr of pepyr. Serve hit forth, & otheyr fysch amonge: turbut, pyke, saumon, chopped & hewn. Sesyn hem with venyger & salt. -anonymous manuscript from fifteenth century

How Much Cod Can Be Caught?

Source: Begon (1996)

From Pauly and Christensen See text 546-547 TABLE 2 Global estimates of primary production (PP), of PPR to sustain world fisheries (mean for 1988-1991, net weight), and of the mean trophic levels (TL) of the catches, by ecosystem type PPR (catches +discards) Ecosystem type

Area (106 km2)

PP (gC m-2 yr -1)

Catch (g m-2 yr -1)

Discards (g m-2 yr -1)

TL of the catch

Mean (%)

95% Confidence interval

Open ocean

332.0

103

0.01

0.002

4.0

1.8

1.3-2.7

Upwellings

0.8

973

22.2

3.36

2.8

25.1

17.8-47.9

Tropical Shelves

8.6

310

2.2

0.671

3.3

24.2

16.1-48.8

Non tropical shelves

18.4

310

1.6

0.706

3.5

35.3

19.2-85.5

Coastal/reef systems

2.0

890

8.0

2.51

2.5

8.3

5.4-19.8

Rivers and lakes

2.0

290

4.3

n.a.

3.0

23.6

11.3-62.9

Weighted means (or total)

(363.8)

126

0.26

0.07

2.8

8.0

6.3-14.4

Assimilation Efficiencies (A/I) for different types of organisms Herbiv ore

Carniv ore

Microbiv ore Saprot roph

Invertebrates

40%

80%

30%

20%

Vertebrates

50%

80%

--

--




P /A %

1 Insectivores

0.86

2 Birds

1.29


1.51

4 Other Mammals

3.14


9.77


25.0


40.7


8 Herbivores

20.8

9 Carnivores

27.6

10 Detritivores

36.2

Non-social insects

11 Herbivores

38.8

12 Detritivores

47.0

13 Carnivores


Krebs Fig 26.4

118 Secondary Production Table 6.1 A simple taxonomic-trpohic categorization of heterographic organisms. For each category the characteristic assimiliation (A/C) and growth (P/A) efficiencies are given. (From Heal and Maclean, 1975.) Trophic Function

Herbivore

Carnivore

Microbivore

Saprotoroph

A/C

P/A

A/C

P/A

A/C

P/A

A/C

P/A

Micro organi sms

-

-

-

-

-

-

-

0.40

Inverti brates

0.40

0.40

0.80

0.30

0.30

0.40

0.20

0.40

Vetebr ate homot herms

0.50

0.02

0.80

0.02

-

-

-

-

Vetebr ate heterot herms

0.50

0.10

0.80

0.10

-

-

-

-

0.30 0.25 n 0.20 o i t r o 0.15 p o r P0.10

0.05 0.00 0

2

4 6 Food chain length

8

10

Georges Bank Cod Summary Georges Bank

240 x 120 km in size

Primary productivity

0.9 kg C / m^2 / year

Cod range from trophic level 4 - 6 Transfer efficiencies ~ 10% between trophic levels

What is a guess at sustainable harvest?

Digression - Confidence Limits and Sensitivity Analysis What if energy transfer was 8% instead of 10%? What if less of Georges Bank was suitable habitat? What about other species of bottom fish? Ecological calculations are almost worthless without some measure of the confidence boundaries. Often confidence is assessed through sensitivity analysis - how much difference would mistakes in the input values make to the final result?

Columbus and Cabot In 1492, Columbus sailed the ocean blue. In 1497 John Cabot “discovers” Cape Cod and the Basque fishing vessels In 1500’s there is a cod rush to Massachusetts up to Newfoundland In 1930’s, factory trawlers arrive. In 1960’s, U.S. and Canada increase fishing effort In 1990’s …

NOAA Pub CRD0204

How could catch be at 50,000 tons for years? Productivity

Biomass (Standing Stock)

What happens to system when cod are removed? Trophic cascades Brooks, J. L. and S. I. Dodson, 1965. Predation, body size, and composition of plankton. Science 150: 28-35 Keystone Species Paine, R. T., 1966. Food web complexity and species diversity. The American Naturalist 100: 65 - 75.

Question: What controls the diversity of and relative abundance of different species in the intertidal community? First careful observations of the community Transplant different species and find which ones are competitively dominant (dominance hierarchy) Construct food web for predatory species What will happen if one of the species is removed? The answer … is in your next EcoBeaker lab

Wrap-up Ecology can make some general predictions about what might happen to Georges Bank system. Ecology can also make some predictions about whether and how long it might take cod populations to recover. More on the first topic at the end of the course, when discussing communities. More on the second topic in a couple weeks, when talking about population growth.


Fall 2003

Lecture 8 – Introduction to Biogeochemical Cycles READINGS FOR NEXT LECTURE: 

Krebs. Chapter 27. Ecosystem Metabolism III: Nutrient Cycles



Ramanujan K. 2003. Ocean plant life slows down and absorbs less carbon. (H, W) http://www.eurekalert.org/pub_releases/2003-09/nsf c-op1091603.php. accessed 9/16/03



Rietschel M. 2003. Analysis pours cold water on flood theory.

Nature.

425:111. (H,W)

Outline for today:

I. Discussion of pre-proposals II. Biogeochemistry a. Dinosaur question b. Reservoirs and residence times c. Example: methane III. Guest speaker: Anna Mehrotra

Study questions: •

•

•

•

•

What are the major compartments that we consider when drawing biogeochemical cycles? What are some of the major sub-compartments that we also consider? Explain what two factors contribute to a compound having a long residence time in an ocean or in the atmosphere. What are some major differences between the global biogeochemical cycles for P vs C, or CO2 vs. CH4? Wetland, rice patties, termites and cows are major sources of CH4. Why? More of a brain teaser than study question (Hint: think about residence times and fluxes, see water cycle Krebs Figure 28.7)

How would a C atom from a dinosaur end up in your sandwich?

Global Nutrient Cycling

Precipitation

Uptake Bioelements in solution

Weathering

H20 (+ volatile Bioelements)

Volatile bioelements only

Terrestrial food w eb

Decomposition

Volatile bioelements only Evaporation Death Dead organic matter

OCEAN Marine food w eb

Losses by water run off Terrestrial biosphere

Dead organic matter Sinking

Adapted from Krebs, 2001. Figure 27.1

Reservoir : How much of a substance is present in one of these compartments Atmosphere

Land

Fresh water

Oceans

Sediments Rocks

100 0.001

Mesopause 80

0.01

MESOSPHERE ) m k( t h gi e H

60

Stratopause

1

40

STRATOSPHERE 20

100

Tropopause TROPOSPHERE

0 -100

-80

-60

-40

1000 -20

0

20

40

Temperature (o C) Adapted from http://www.met-office.gov.uk/research/stratosphere/

) a P (h e r u s s e r P

Global Methane Cycle (units of

1012

g CH4/yr)

Sources 535

Sinks 515

(Natural 160 + Anthropogenic 375)

stratosphere 40

445

CH4

100

fossil fuel (mining, burning)

troposphere Reaction with OH

85 30 cows landfills + other waste treatment Data from Schlesinger, 1997

115

30

10

90 termites wetlands

oceans

Estimated Sources and Sinks of Methane in the Atmosphere in Units of 1012 g CH4 /yr a Sources

Range

Likely

Natural Wetlands Tropics Northern latitude Others Termites Ocean Fres hwater Geological Total

30 20 510 515-

80 60 15 50 50 25 15

65 40 10 20 10 5 10 160

45 50 30 30

30 40 15 15

20 - 70 20 - 30 15 - 80 65 -100 20 - 80 20 -100

40 25 25 85 40 60 375

An th ro po gen ic Fossil fuel related Coal mines Natural gas Petroleum industry Coal combustion Waste management system Landfills Animal waste Domestic sewage treatment Enteric fermentation Biomass burning Rice paddies Total

15 25 55-

Total sources Sinks Reaction with OH Removal in stratosphere Removal by soils

535

330 -560 25 - 55 15 - 45

Total sinks Atmospheric increase

445 40 30 515

30- 35

30

What is the probability that a water molecule from Napoleon’s urine is in your water bottle?

Pools (km3)

The Global Water Cycle

Fluxes (km3/yr)

Atmosphere 13,000 Net transport to land

11,000

71,000 40,000

Ice 33,000,000

River flow 40,000 Soil Waters 122,000

Groundwater 15,300,000 Reference: Schlesinger, 1997

385,000

425,000

Oceans 1,350,000,000


Fall 2003

Lecture 9 – Nitrogen and Phosphorus Cycling Outline for today:

I. Review of Biogeochemical cycling mechanics and Mass balance a. Reservoirs and Fluxes b. Sources and sinks II. Nitrogen a. Role in biology b. Reservoirs c. Nitrogen Sources d. Nitrogen Sinks III. Phosphorus a. Role in biology b. Reservoirs c. Phosphorus Sources d. Phosphorus Sinks

Study questions: • • •

Why is nitrogen fixation only carried out by prokaryotes? Why didn’t humans and plants evolve a way to fix nitrogen from the atmosphere directly? Would nutrients have a longer residence time in deciduous or coniferous forests? Why? In today’s Nitrogen cycle is nitrogen fixation balanced by denitrification?

I. Review of Biogeochemical cycling mechanics and Mass balance a. Reservoirs and Fluxes, Sources and sinks Inputs > outputs (sink) Inputs < outputs (source) Mass balace: ΣInputs - ΣOutputs + ΣSources - ΣSinks = ∆Mass Steady state: ∆Mass =0 II. Nitrogen Atomic # 7 … 14.0067 g mol –1 a. Role in biology

B.P. –195.8°C

N is an essential component of proteins, nucleic acids and other cellular constituents.

b. Reservoirs – 79% of the atmosphere is N 2 gas. The N=N triple bond is relatively difficult to break ,requires special conditions. As a result most ecosystems are N-limited. N2 dissolves in water, cycles through air, water and living tissue.

c. Nitrogen Fixation

Abiotic: lightning (very high T and P) 10 7 metric tons yr -1 ~ 5-8% of total annual N fixation. (weathering of rocks is an insignificant source) Biotic: Nitrogen fixation by microbes, (prokaryotic bacteria) typically either freeliving azobacter or rhizobium living symbiotically with plants (such as legumes). Total N fixed by biological processes is approx. 1.75 x10 8 metric tons yr -1 Biological mechanism of nitrogen fixation: uses an enzyme complex called nitrogenase consisting of two proteins – an iron protein and a molybdenum-iron protein.

N2+ 8H+ + 8e -+ 16 ATP = 2NH 3+ H2+ 16ADP + 16 Pi oxidised f erredoxin

reduced f erredoxin

oxidised Fe protein

reduced Fe protein 4 ATP

2e-

4 AFP

reduced Mo Fe protein

oxidised Mo Fe protein 2e-

2 H+

HN=NH

N2

H2 N=NH2

HN=NH

2NH3

H2 N=NH2

Adapted from http://helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm#Top

The Fe protein gets reduced by electrons donated by ferredoxin. Then the reduced Fe protein binds ATP and reduces the molybdenum-iron protein, which donates electrons to N2, producing HN=NH. In two further cycles of this process (each requiring electrons donated by ferredoxin) HN=NH is reduced to H2N-NH2, and this in turn is reduced to 2NH3. •

•

ferredoxin is generated by either photosynthesis, respiration or fermentation, depending on the type of organism nitrogenase is inhibited in the presence of oxygen. N-fixing prokaryotes operate either anaerobically (Clostridium, Desulfovibrio, Purple sulfphur Bacteria ) or develop special mechanisms such as extremely high respiratory rates ( Azobacter ) and/or cellular features to limit oxygen diffusion, or else develop symbiotic relationships (Rhizobium) where the host plant scavenges oxygen. Cyanobacteria, protect nitrogenase in special heterocysts which possess only PS I.

Industrial: The Haber-Bosch process (1909)– high P and relatively high T, uses Iron as a catalyst to convert N 2 to ammonia (usually further processed to urea and ammonium nitrate (NH 4NO3) – still the cheapest means of industrial N fixation. 5x10 7 metric tons yr -1 Combustion Side Effect: High T and P oxidizes N 2 to Nox 2x10 7 metric tons yr -1

Since 1940s amount of N available for uptake has more than doubled.

Anthropogenic N

inputs are now equal to biological fixation. d. Nitrogen Cycling

plants directly take up NH4+ or NO3-

Nitrification by chemoautotrophs Bacteria of the genus Nitrosomonas oxidize NH 3 to NO2Baceria of the genus Nitrobacter oxidize the nitrites to NO 3Denitrication Anaerobic respiration of NO3- to dinitrogen gas by several specis of Psuedomonas, Alkaligenes, and Bacillus Sources of anthropogenic N loads: Fertilizers, Legume Crops, Atm Deposition, Sewage, Deforestation, Draining of wetlands Trends in Fertilizer Use

(million metric tons 160 140 120 100 80 60 40 20 0 1960 1965

1970

1975

AFRIC ASIA EUROPE NORTH AMERICA

1980

1985

1990

1995

OCEANIA SOUTH AND CENTRAL A MERICA WORLD

Adapted from the Food and Agriculture Organization of the United Nations (FAO), FAOSTAT Statistical Database (FAO, Rome, 1997).

Fate of N? In most terrestrial and freshwater ecosystems N is a limiting nutrient, gets cycled efficiently. What happens when plants have enough N (i.e. greater 16:1 N:P ratio)? Flushing/erosion – dissolved and particulate matter in streamwater, (DIN, DON, TN, Org N) leaching to groundwater – NO3- is an anion, does not sorb well to clays, highly water soluble. When N saturation of ecosystem occurs, excess N tends to leave the system in the form of nitrate. , VOCs, denitrification, burning, emigration, harvesting

Effects of Increased N loading: Eutrophication in aquatic systems, coastal algal blooms and “Dead Zone”, fish kills, increased turbidity, selective pressures in terrestrial systems favoring species-poor grasslands and forests Nitrate MCL – 10mg L -1 … Nitric oxide – precursor of acid rain and smog Nitrous oxide – long lived greenhouse gas that can trap 200 times as much heat as CO 2 III. Phosphorus – Atomic # 15 … 30.97 g mol –1

B.P. 280°C

P is very reactive, does not exist in pure elemental form. In contact with air, it forms phosphate PO43-. In water, phosphates are protonated to form HPO42-, H2PO4- and H3PO4. PO43- orthophosphate, the most simple molecular form of phosphate, aqueous form under very basic or alkaline conditions HPO42- : aqueous form under basic or alkaline conditions H2PO4- : aqueous form under neutral conditions H3PO4 : aqueous form under very acidic conditions

a. Role in biology 3-

2-

Phosphorus is an essential nutrient for plants and animals in the form of ions PO4 and HPO4 . It is found in DNA-molecules (it binds deoxyribose sugars together forming the backbone of the DNA molecule), ATP and ADP, and lipid cell membranes (phospholipids). P is also a fundemental to tissues such as bones and teeth.

b. Reservoirs – Unlike C, N and other important bioelements P does not exist in a gaseous state at typical environmental Temps and Pressures. Cycles through water (DOP and DIP), soils and sediments (adsorption to mineral surfaces) and organic tissue/humic material.

c. Phosphorus Sources – Found in sedimentary rocks such as apatite (Cax(OH)y(PO4)z), fossilized bone or guano. Weathering from phosphate rocks found in terrestrial rock formations and some ocean sediments (PO 4 is soluble in H2O). Guano (excrement of fish-eating birds) mining for fertilizers and sewage. Detergents have historically contained Na 3PO4, though newer types are avoiding it. d. Phosphorus Sinks – uptake of orthophosphate by plants through the roots, incorporation into plant tissue and heterotroph tissues, decomposition returns P to water and soils via microbial mineralization; eventually it is washed out to the oceans, sinks to the floor (becomes limestone) and is not recycled for millions of years.

Adapted from:

http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_phosphorus.htm


Fall 2003

Lecture 10 – Sulfur Cycles READINGS FOR NEXT LECTURE: 

Krebs Chapter 28 pages 590-607

READINGS FOR NEXT THURSDAY’S LECTURE: 

Global climate change articles (handed out separately)

Outline for today: I. Quizzes II. Global climate change discussion next Thursday III. Sulfur A. Reservoirs and residence times B. Biology of sulfur C. Global S cycle D. Human Impacts E. Isotope analyses

III. Sulfur A. Reservoirs and residence times

Reservoir

Size (10 Size (1012 g)

Flux (1012 g/yr)

Atmosphere

2

270

__________

Seawater

1.3 x 109

310

__________ _________

Sedimentary Rocks

7.4 x 109

220

__________

MRT (yr)

Land Plants

8500

24

__________

Soil Organic Matter

16000

72

__________

Will S be well-mixed in the atmosphere?

B. Biology of sulfur reduced

oxidized assimilation

org S

mineralization (decomposition)

SO4

-

S

requires energy releases energy

H2S

C. Global cycle Adapted from Smith,200. Elements of Ecology.

The Global Sulfur Cycle Wet and dry deposition 90

Fluxes (10 12 g S/yr)

Transport to sea

5 8

20

90

Transport to land 4 4

Dust

5

180

Biogenic gases

144

Deposit ion

130

Sea salt

16

Biogenic gases

Rivers Human mining and extraction 150

Reference: Schlesinger, 1997

Natural weathering and erosion 72 Pyrite 39

D. Human impacts Global SO2 Emissions

Hydrothermal sulfides 96

Adapted from Charlson et al. 1992 Science 255:423 E. Isotope analyses 34

S = 1000 * [(34S/32S)sample – (34S/32S)standard] / (34S/32S)standard

in ‰

Smelters, Refineries, Automobiles? δS34 = +1.5

δS34 = +3.1

δS34 =+16 δS34 =+1 δS34 =+5.3

H2S

Great Salt Lake

Copper Smelters

Refineries

Autos

Anaerobic bacteria

δS34 = +1.5

Mean Values

δS34 = +3.1

Smelters Strike δS34 = +5.3

(expected +9)

Mean Values

δS34 = +6.4

(expected +16)

Study questions: • • • • •

Name the major ways in which the sulfur cycle resembles and does not resemble the nitrogen and phosphorus cycles. What are major anthropogenic and non-anthropogenic sources of S emissions into the atmosphere? How does acid rain form? How does acid mine drainage form? Explain how sulfate reducing bacteria indirectly create SO2 emissions. Explain how isotope ratios can be used to determine the relative contributions of different sources.


Fall 2003

Lecture 11 – Carbon Cycle READINGS FOR NEXT LECTURE: 

Global climate change articles (handed out last class)



Whitehouse D. 2003. Photosynthesis puzzle solved. BBC. http://news.bbc.co.uk/2/hi/science/nature/3174582.stm. accessed 10/10/03



Bentley M. 2003. Synthetic trees could purify air. BBC. http://news.bbc.co.uk/2/hi/science/nature/2784227.stm. accessed 10/10/03

Outline for today: I. Finish S cycle / Stable Isotope Analyses II. Global Carbon Cycle A. C in the news B. Global cycle C. Carbon and temperature D. Ecological effects of increasing CO2

The Global Carbon Cycle fossil fuel burning

6

GPP

Land plants 560

Rp

Atmospheric Pool 750 120

+3.2/yr

60 60 0.9

92

Soils 1500 Pools

(10 15 g

90

Rivers 0.8 Net destruction of vegetation

C)

Fluxes (10 15 g C/yr)

Rocks 81,000,000

Reference: Schlesinger, 1997

Fossil Fuels 4000

Ocean 38,000

Burial 0.1

Measured changes in CO 2 dissolved on the surface of the Atlantic ocean.

Adapted from: Schlesinger, 1997 (Figure 9.10)

Adapted from Krebs, Fig. 28.13

Adapted from Krebs, Fig. 28.11 Trees from Arizon, North Carolina and Italy

Concentration of CO2 at Mauna Loa Observatory In Hawaii. Adapted from Krebs Fig 28.9.

Long-term variation in global temperature and atmospheric CO2 concentration determined from the Vostok Ice Core, Antarctica. Adapted from Krebs. Fig. 28.15

Temperatures Relative to Millenial Average*. Adapted from Mann et.al., 1999

It’s not just CO 2 Atmospheric Concentration (ppm)

Annual Concentration Increase (%)

Relative greenhouse efficiency (CO2 = 1)

Current Greenhouse Contribution (%)

Carbon dioxide

351

0.4

1

57

CFC’s

0.00225

5

15 000

25

Foams, aerosols, solvents, refrigeration

Methane

1.675

1

25

12

Wetlands, rice, livestock, fossil fuels

Nitrous oxide

0.31

0.2

230

6

Fuels, fertilizer, deforestation

Gas

Principal sources of gas Fossil fuels, deforestation

Source: Schlesinger, 1997

Effects of increased CO2 on Phytoplankton: Riebesell U., et. al. “Reduced calcification of Marine phytoplankton in response to increased Atmospheric CO2. Nature 407:364 (2000).

Time variation of Larval weight (adapted from Krebs Fig. 28.17)

Read: AGNIESZKA BISKUP ,

“GET THE OCEANS SOME TUMS”

Published on October 7, 2003, Boston Globe, Page C2 Col 2

Study questions • • • • •

What are the largest C reservoirs and fluxes in the environment? What do we mean by the “missing carbon”? Where is this “missing” carbon likely to be? How do temperate forests respond to elevated CO2 after 1-5 years? 30 years? How can stable isotopes be used to determine temperature 1000s of years ago? By what mechanism do oceans primarily absorb CO2?


Fall 2003

Global Climate Change Discussion – 10/16/03 The dramatic increase in atmospheric CO 2 concentrations is alarming to many people. While reduction in emissions is the obvious solution, some people are proposing more immediate actions to reduce the amount of CO 2 in the atmosphere. Some proposed ideas are iron-fertilization, deep-sea injection of CO2 and carbon sequestration in terrestrial plants. There is also a lot of debate about whether increasing CO 2 concentrations will lead to greater terrestrial and aquatic productivity, which could serve as a feedback mechanism to absorb some of the extra atmospheric CO 2. We’re going to spend a lecture evaluating these topics. To make the discussion more informative, I’ve assigned some readings pertinent to each topic. Each person is responsible for reading one set of articles. You should be prepared to talk about the answers to the questions below, drawing on the major points of the below articles and any other information you find (these articles were some that I found briefly searching through Nature & Science ). When you get to class, you will break into groups, share your answers to the questions, and prepare to explain your topic to the class. As you read these articles, keep the following questions in mind: What is the rationale behind each approach? How will this approach work to reduce atmospheric CO2? In which compartment of the environment will the C be stored? What is the MRT? Can it work in the short-run? In the long-run? What are other effects besides decreasing atmospheric CO 2? What are the major uncertainties? Overall, do you think it’s a good idea? Would your answer be different if you lived in Holland or on a tiny island barely above sea level? •

• • • • •

Everyone (focus on pages 422-426A) Betts KS. 2000. Engineering maintainable development. Environmental Science and Technology . 34:422A.

1. Ecological responses to high CO 2 concentrations (Adrienne, April, Ayse, Ben, Candace, Cynthia) Norby R. 1997. Inside the black box. Nature . 388:522. Sarmiento J. 2000. That sinking feeling. Nature . 408:155. Schlesinger WH and JH Lichter. 2001. Limited carbon storage in soil and litter of experimental forest plots under increased atmospheric CO 2. Nature . 411:466. DeLucia EH. 1999. Net primary productivity of a forest ecosystem with experimental CO 2 enrichment. Science . 284:1177. Gill RA et al . 2002. Nonlinear grassland responses to past and future atmospheric CO 2. Nature . 417:279.

2. Deep-Sea or Mineral Injection of CO2 (Genevieve, Helen, Jason, Jennifer, Jessie, Jonathon, Katie) Dalton R. 1999. US warms to carbon sequestration research. Nature . 401:315. Kaiser J. 1998. A way to make CO 2 go away: Deep-six it. Science . 281:505. Seibel BA and PJ Walsh. 2001. Potential impacts of CO 2 injection on deep-sea biota. Science . 294:319. Celia MA. 2001. How hydrogeology can save the world. Ground Water . Caldeira K and ME Wickett. 2003. Anthropogenic carbon and ocean pH. Nature . 425:365. Lackner KS. 2003. A guide to CO 2 sequestration. Science . 300:1677. 3. C sequestration in terrestrial systems (Kelly, Ling, Liz, Lynn, Marion, Maywa, Melissa) Smaglik P. 2000. United States backs soil strategy in fight against global warming. Nature . 406:549. Körner C. 2003. Slow in, rapid out – carbon flux studies and Kyoto targets. Science . 300:1242. Goodale CL and EA Davidson. 2002. Uncertain sinks in the shrubs. Nature . 418:593. Betts RA. 2000. Offset of the potential carbon sink from boreal forestation by decreases in surface albedo. Nature . 408:187. Fang J et al . 2001. Changes in forest biomass carbon storage in China between 1949 and 1998. Science . 292:2320.

4. Iron Fertilization of Open Oceans (Michael, Nicole, Nina, Priya, Schuyler, Tom) Buesseler KO and PW Boyd. 2003. Will ocean fertilization work? Science . 300:67. Chisholm SW, PG Falkowski, and JJ Cullen. 2001. Dis-crediting ocean fertilization. Science . 294:309. Watson AJ et al . 2000. Effect of iron supply on Southern Ocean CO 2 uptake and implications for glacial atmospheric CO2. Nature . 407:730. Lawrence MG. 2002. Side effect of oceanic iron fertilization. Science . 297:1993. Lam PJ and SW Chisholm. 2002. Iron fertilization of the oceans: Reconciling commercial claims with published models. http://web.mit.edu/chisholm/www/Fefert.pdf. accessed 10/8/03.


Ecology

Populations Communities Ecosystems

Population Ecology How do populations grow? Most widely used branch of ecology Endangered species •Invasive species •Agricultural Pests •Disease dynamics

Major Problem: People vs. Elephants •Park is too small for the elephants. •People are settling outside the park •Elephants like farm food •Elephants and cows both need water

Task: Make a model of elephant population dynamics to ask “what-if” questions about purchasing more land.

w/ Sandy Andelman Data from (2001) Moss, CJ. J Zool. 255: 145-156

How will the elephant population grow? dN/dt = B - D + I - E B = Births D = Deaths I = Immigration E = Emigration

Continuous Exponential Growth Births = bNt Deaths = dNt

Ignore I and E for now

dN/dt = bNt - dNt = (b - d) Nt = r Nt

Integrate to get Nt =

r = “Intrinsic rate of growth”

Discrete Exponential Growth Nt = Nt-1 + bNt-1 - dNt-1 + I - E Ignoring I and E, we get

Nt = (b - d) Nt-1 = r Nt - 1

Try this equation in a spreadsheet.

Density Dependence Nt = rNt-1 (1 - N / K) “Logistic Growth Equation” K = Carrying capacity

Try r of different values and graph

Digression: Chaos

Digression: Growth rate vs. Population Size

This graph is the basis of population management and harvesting. For instance, the cod fishery might be managed using a graph like this. Measuring this turns out to be very hard

Age at First Reproduction Nt = bNt-a - dNt-1 1.0

n 0.8 o i t r o 0.6 p o r p e 0.4 v i t a 0.2 l u m u C0.0 -0.2 0

2

4

6

8

10

12

14

16 18

20

22

Age at first known birth Probability of first birth occurring at each age for known-age females.

Try changing these and see how it affects doubling time

Digression: Why wait to reproduce? Obviously, you will have more offspring faster if you reproduce sooner. Why doesn’t everything reproduce as soon as its born?

R-selected species: reproduce very at young age and small size / resources. K-selected species: reproduce at older age and larger size / resources

Environmental Stochasticity

Demographic Stochasticity What happens when population is small? Small numbers means that probability comes into play.

Allee effect When population is small, some things may get harder (like finding mates) If so, fecundity could actually decrease at low population size.

Some Terms •Intrinsic rate of growth: maximum offspring / individual / time •Doubling time: Amount of time for population to double •Carrying capacity: The maximum population that the environment can sustain •Discrete vs. continuous: Do events happen continuously or once per some unit of time (such as once per year). •Density-dependent/ independent: Are the parameters like b and d dependent on the density of the population •Demographic stochasticity: When populations are low enough, chance events matter to the population size. •Alee effect: Fecundity decreasing at low population size


Recap Basic Population Dynamics Eqn dN/dt = B - D + I - E Continuous Exponential growth dN/dt = rN Discrete Exponential growth N(t) = N(t-1) + rN(t-1) Discrete Logistic growth N(t) = N(t-1) + rN(t-1)[(K-N(t-1))/K]

Digression: Why wait to reproduce? Obviously, you will have more offspring faster if you reproduce sooner. Why doesn’t everything reproduce as soon as its born?

R-selected species: reproduce at young age and small size or resources. K-selected species: reproduce at older age and larger size or resources

Demographic Stochasticity What happens when population is small? Small numbers means that probability comes into play.

Allee effect When population is small, some things may get harder (like finding mates) If so, fecundity could actually decrease at low population size.

Estimating Population Size With luck, you can count (like elephants) Normally, you must sample. Sampling, and analyzing samples, is 90% of most ecologists’ job.

Some sampling techniques

Estimating Model Parameters 1. 2. 3. 4. 5.

Plot data Select a growth equation Select parameters for that growth equation Plot the equation over the data Measure the distance of the equation plot from the data points 6. Change the parameters and repeat 7. Select the parameters that give the “best-fit” to the data 8. You can repeat this with a different equation and see which one fits better - if equations have different numbers of parameters, must take into account that its easier to fit data with more parameters.

Split Data Into Ages or Stages birth rate

death rate

Juvenile

0

0.02

Adult

0.2

0.01

Ancient

0.05

0.05

N(juvenile, t) = 0.98 * N(juvenile, t-1) + 0.2 * N(adult, t-1) + 0.05 * N(ancient, t-1) N(adult, t) = 0.99 * N(adult, t-1) + prop_age_14 * N(juvenile, t-1) N(ancient, t) = 0.95 * N(ancient,t-1) + prop_age_55 * N(adult,t-1)

Life Tables Just using matrices to organize data on birth and death rates at different ages / stages. N(juvenile, t) = 0.98 * N(juvenile, t-1) + 0.2 * N(adult, t-1) + 0.05 * N(ancient, t-1) N(adult, t) = 0.99 * N(adult, t-1) + prop_age_14 * N(juvenile, t-1) N(ancient, t) = 0.95 * N(ancient,t-1) + prop_age_55 * N(adult,t-1)

juv adult = Ancient

|0.91 |0.02 |0

0.2 0.99 0.06

0.05 0 0.95

| | |

*

juv adult ancient

Life Tables are just Matrices Eigenvector = “Stable age distribution” Eigenvalue = “Growth rate”

Sensitivity Analysis In general, population dynamics is not useful for making accurate quantitative predictions. It’s useful for making qualitative predictions comparing different scenarios.

Individual-based Models “EcoBeaker”-style Follow individual creatures. Each creature can have its own Variables Pluses • Can have infinite stages, ages, etc. • Can account for space, interactions between individuals

Minuses • Often lots of parameters • Limits on number of creatures • Hard to make general conclusions

Some Terms •Intrinsic rate of growth: maximum offspring / individual / time •Doubling time: Amount of time for population to double •Carrying capacity: The maximum population that the environment can sustain •Discrete vs. continuous: Do events happen continuously or once per some unit of time (such as once per year). •Density-dependent/ independent: Are the parameters like b and d dependent on the density of the population •Demographic stochasticity: When populations are low enough, chance events matter to the population size. •Alee effect: Fecundity decreasing at low population size •Stable age/stage distribution - the eigenvector for the life table matrix


Fall 2003

Lecture 15 – Human Population Growth READINGS FOR NEXT LECTURE: (some of these are fr om last week’s lectures) 

Krebs Chapter 28: Pages 583-590.



Krebs Chapter 9: “Population Parameters”



Krebs Chapter 10: “Demographic Techniques: Vital Statistics”



Krebs Chapter 11: “Population Growth”

Outline for today: 1. Historic al population growt h 2. Carryi ng capacity and ecological footprint s 3. Lif e tables 4. Guest speaker: David Greene

Study Questions: •

•

•

•

•

Describe the concept of carrying capacity. Why is it hard to define the carrying capacity of a country? Doubling times for human population have decreased significantly over the past 2000 years. What does this imply about the rate of growth? (Use an equation) Define the concept of ecological footprint, and what is involved with calculating one. Compare the ecological footprint of N. America and Asia. Compare stable and expansive populations, and explain the idea of population momentum. How do life tables help you predict future population growth?

1

Life table nx = number of individuals in age group qx = mortality rate for individuals in age group bx = number of babies born per person (or female) over time interval

1. Fill in boldly-outlined boxes.

2. Is this an expansive or stable population? 3. Which of the above numbers would change if: (a) teenage pregnancy rates went down? (b) all women delayed having births by 10 years? (c) infant mortality rates increased? (d) a new drug is introduced which lowers heart attacks in 40-49 year olds?

Age group

1980 pop’n (millions) (nx)

Mortality rate (qx)

Birth rate (bx)

0-9

215

0.005

0

10-19

167

0.009

0.1

20-29

132

0.015

0.3

30-39

119

0.027

0.05

40-49

86

0.042

0

50-59

55

0.054

0

...

..

..

..

1990 pop’n (millions)


..

..

in this case, b x is based on number born per person (not per female)

2

Human Population Growth

Krebs, 2001 (Figure 28.1)

Doubling times Year (AD)

Population (billions)

0

0.25

1650

0.5

1850

1.0

1930

2.0

1975

4.0

1650 years 200 years 80 years 45 years

Carrying capacity = 197 million ) s n o i l l i m ( n o i t a l u p o P

logistic curve

In 1924, Pearl and Reed fit U.S. population data for 1790-1910 using the logistic equation. Joel E. Cohen, How Many People Can the Earth Support? Norton 1995

) s n o i l l i m ( n o i t a l u p o P

In 1990, the population of the U.S. was 250 million Joel E. Cohen, How Many People Can the Earth Support? Norton 1995

Ecological Footprint Krebs, 2001 (Figure 28.6)

Ecological footprint by region, 1996 North America Western Europe Central and Eastern Europe Middle East and Central Asia

12 n o10 s r e p 8 r e p s 6 t i n u 4 a e r 2 A

Latin America & Caribbean Asia / Pacific Africa

OECD average

non-OECD average

0 299

343 484 384 307

3222

710

Population (millions)

Adapted from: WWF, UNEP World Conservation Monitoring Centre, et al. 2000. Living Planet Report 2000. Gland, Switzerland: WWF.

9 hectares / person = 90,000 m2 / person

300 m

Manhattan has 1.5 million people on 21.8 square miles

at 9 ha/person (1 ha=10 4 m2), what is Manhattan’s ecological footprint?

Manhattan’s ecological footprint = 54,000 square miles

Estimates of Earth’s Carrying Capacity


“Expansive” population distribution

Source: www.wri.org

“Stable” population distribution

Source: www.wri.org

Adapted from: www.wri.org

Fertility Decline 1950 - 1998


Hypothetical Survivorship Curves

Source: Krebs, 2001(Figure 10.2)

Life Tables Age group

1980 pop’n (millions) (nx)

Mortality rate (qx)

Birth rate (bx)

0-9

215

0.005

0

10-19

167

0.009

0.1

20-29

132

0.015

0.3

30-39

119

0.027

0.05

40-49

86

0.042

0

50-59

55

0.054

0

..

..

..

..



..

..


Fall 2003

Lecture 16 – Competition READINGS: 

Krebs Chapter 12: Species Interactions: Competition



Krebs Chapter 22 pages 447-448.

Outline for today: I. Life tables (from last class) II. Competition a. Resource vs interference competition b. Lotka-Volterra equations c. Tilman’s approach d. Niches

Study questions •

Explain the difference between resource and interference competition. Give an example of each.

•

What do α and β in the Lotka-Volterra equations represent?

•

For the 4 general cases of the Lotka-Volterra equations, will in > or < in the following inequalities, and describe whether inter- or intraspecific competition is more important for species 1 and 2 K1 ___ K2/β

K2 ___ K1/α

•

What were Tilman’s criticisms of the Lotka-Volterra approach? Describe Tilman’s approach to determining the outcome of competition between two species.

•

Suppose the densities of two species A and B are 60 and 30 organisms per acre. Their carrying capacities are 65 and 80 organisms per acre, respectively. Can you say whether or not these species could be in stable coexistence as described by the Lotka-Volterra Equations? Why or why not? What if the densities of the two species are 20 and 20 organisms per acre, respectively. What can you say now?


Lecture 17 – Competition and Niches READINGS: 

Krebs Chapter 13: Species Interactions: Predation

Outline for today: I. Finish competition a. Tilman’s approach b. Competitive exclusion principle c. Character displacement and resource partitioning d. Fundamental and Realized Niches

Study questions • • •

Explain the difference between a fundamental and a realized niche. Explain character displacement and provide and example Explain the significance of Gause’s experiments with paramecium.

Gause’s paramecium experiments

Fall 2003

Fundemental vs. realized niche

Independent vs. inter-dependent niches (a)

(b)

(c)

A

A

A B

B

A

B

A B

B

A

B

Two species, A and B (a) Niches are independent (b) and (c) Niches are partially dependent

Macarthur’s Warblers: See Krebs 12.15

2

Supplement to class (11/6):

Clarifying Tilman’s approach: Consider the graph for one species, Species A:

Suppose that Species A uses Resources 1 and 2 in the ratio of 2:1 (shown by the dotted line)

Zone 1

R2

Zone 2

R1

If the supply point falls in Zone 1 (above the line), then R1 will be limiting. In other words, if Species A uses up the resources at a constant 2:1 ratio, and the supply point ratio of R1:R2 is less than 2:1, then Species A will run out of R1 first. Below the line, in Zone 2, R2 will be limiting.

For Species A, because the usage ratio of R1:R2 is greater than 1, Species A is more efficient at using R2, and it is generally considered to be limited by R1. Whether or not it will actually be limited by R1 depends on conditions in the environment (whether your starting point is in Zone 1 or 2).

Consider the graph for Species B:

Now let’s consider the case for Species B. Zone 1

R2

Again in Zone 1 (above the dotted line), Species B will be limited by R1, and below the line will be limited by R2.

Zone 2

Generally speaking, Species B will be more limited by R2, and is considered more efficient at using R1. R1

Species A and B together:

1 Species A and B both lose

CB

2 Species B wins over Species A

3

R2 2

4

C CA

A

5

3 Falls within Zone 1 for both Species A and B. Hence, R1 will be limiting for both. Since Species B is more efficient at using R1, it will predominate.

B

4 Here, A will be limited by R1 and B will be limited by R2. Since B is generally A 1 more limited by R2 and A is generally R1 limited by R1, neither species will have a competitive advantage over the other and both will be limited. This is the zone of coexistence. The stable equilibrium point will occur at the intersection of the two lines (since dN/dt=0 for both species here). 6

5 Falls within Zone 2 for both Species, meaning that R2 will be limiting for both species. Since Species A is more efficient at using R2, Species A will be able to outcompete Species B in this region. 6 Species A wins over Species B Independent vs. inter-dependent niches

Independent vs. inter-dependent niches (a)

The axes in graphs on right represent availability of two resources. The arrows show the range of availabilities that will permit the growth of Species A and B.

(b)

(c)

A

A

A B

B

A

Let’s consider the shape of the niche for just Species A, in two dimensions. There are three general shapes for the two-dimensional niche.

B

A B

A

B

B

Two species, A and B (a) Niches are independent (b) and (c) Niches are partially dependent

(1) No interdependence of niches. At high availability of R1, any level of R2 will permit growth. (2) Interdependent niche. At high availability of R1 (e.g. bright sunlight for a plant), Species A requires high availability of R2 (e.g. high water availability) in order to grow. (3) Interdependent niche. This time, high availability of R1 permits Species A to grow only if availability of R2 is low. 1

2

R2

3

R2

A

A

R2

A

A R1

R1

R1


Fall 2003

Lecture 18 – Predation READINGS: 

Gilg O, I Hanski and B Sittler. 2003. Cyclic dynamics in a simple vertebrate predator-prey community. Science. 302:866.



Turchin P, L Oksanen, et al . 2000. Are lemmings prey or predators?



Tilman D. 2000. Causes, consequences and ethics of biodiversity.



Ranta E. 2003. Making sense of complex population cycles.

Nature.

Nature.

Science.

405:562.

405:208.

301:171.

Outline for today: I. Predation a. Lotka-Volterra b. Rosenweig-MacArthur c. Functional Response Curves -- Holling II. Guest Speaker, Aladdine Joroff (’00)

Lemmings: Predator or Prey?

Study Questions •

•

•

•

•

•

What is unrealistic about Lotka-Volterra’s approach to modeling predator-prey interactions? What other shapes can the isoclines assume? What situations are stable and unstable in Rosenweig-MacArthur’s approach? What changes might make stable interactions unstable? Sketch the Type I, II and III Functional Response Curves and describe what the shapes of the curves mean. According to Tilman, how does competition among members of a single trophic level serve to stabilize communities? What are the requirements for coexistence? Compare the findings of Gilg et al. and Turchin et al . Are their findings compatible with each other? In the Gilg et al . paper, what type of function response curves do the predators exhibit with respect to lemming density?

Creating Stable Oscillations in Lab Settings Adapted from Krebs Fig. 13.2


2

Huffaker Adapted from Krebs Fig. 13.8

Oscillations in Natural Settings

3

Functional Responses: Type II Adapted from Krebs Fig. 13.17

4


Conservation Examples

Population Viability Analysis - Butterflies and Restoration Indicator Species - Good idea? Hotspots

Endangered Species Part of declaring a species endangered involves doing a Population Viability Analysis (PVA) A population is not considered endangered if it has 95% chance of persisting for 100 years. Once a species is declared endangered, it gets a “recovery plan” •What will be done to help it •When is it considered “recovered”

Fender’s Blue Butterfly Pretty butterfly that lives in western Oregon Lays eggs on Kincaid’s Lupine Kincaid’s Lupine only grows in “old growth” prairies Prairies are prime land for farms, suburbs, shopping malls, universities… Both Kincaid’s Lupine and Fender’s Blue Butterfly were recently listed as endangered species. Sources: Schultz and Hammond (2003) Conservation Biology 17:1372-1385. Schultz (1998) Conservation Biology 12: 284-298 E. Crone, pers. comm.

Population Viability for Fender’s Blue Data: •Yearly population census in different patches Assume: •Density independent growth •No observer error •No exceptional years

Use exponential growth equation N(t+1) = N(t) + (r + ε) N(t) ε

= error term

Growth rate and variance for Fender’s Blue Site

Ownership

Protected status

Number of censuses

Average population sizec

Butterfly Meadowsd Fern Ridge – Eaton Lane Fern Ridge – Spires Lane Fir Butte Willow CreekBailey Hill Willow CreekMain Area Willow Creek North Area Basket Butte Gopher Valley McTimmonds Valley Mill Creek Oak Ridge

Private

Unprotected

8

412

1.06

Variance in population growth rate 2 ( ) 0.122

Public

Protected

9

5

2.66

1.461

Public

Protected

9

22

1.92

1.338

Public Private

Protected Protected

8 9

54 77

1.61 1.34

0.861 0.692

Private

Protected

9

738

1.15

0.387

Private

Protected

9

43

1.56

0.918

Public Private Public

Protected Unprotected Unprotected e

8 8 9

589 10 11

1.12 0.99 2.02

0.436 0.468 1.715

Public Private

Unprotected e Unprotected

10 9

17 149

1.31 1.21

0.607 0.448

Avg. growth rate = 1.49 Avg. variance = 0.79 (for sites with > 25 butterflies = 0.54)

Chance of Persistence

Population growth rate ( )

Multiple Patches = Metapopulation Metapopulation Chance of survival with no colonization is: survival anywhere = 1 - Π (1 - surviv survival ali) i Chance of survival WITH colonization will be higher

Metapopulation can survive even when all patches will Individually go extinct

Prairie Restoration Measure •Flight paths •Chance to leave lupine area •Daily time budget •Lifespan Model different habitat configurations and ask which increases survival the most.

Fender’s Blue Butterflies: Live ~ 10 days Fly ~ 2.3 hours / day Disperse within lupine ~ 3 m 2 /s Disperse outside lupine ~ 15 m 2 /s Weakly bias flight towards lupine patches Butterfly might go 0.75 km within lupine 2 km outside of lupine Historically, patches ~ 0.5 km apart Now patches patches 3 - 30 km apart

Other Examples of Recommendations Spotted Owls Save old growth trees Sea Turtles Protect the adults, forget the eggs Sea Otters Based PVA on risks of oil spills, recommend number and area for recovery

Problem Fender’s Blue study: •8 years dedicated study by grad student, TNC personnel •Undergraduate field assistants •Lots of volunteers

Impossible to do for very many species

Indicator Species A well-studied species whose protection will also protect many other less weel-studied species. What makes a good indicator?

Hot Spots Places with high biodiversity, especially many endemic species

Brooks et al., (2002) Habitat loss and extinction in the hotspots of biodiversity. Conservation Biology 16: 909-924.

Save Hotspots to Save Diversity? Myers et. al. claim that 1.4% of land area contains 44% of vascular plants and 35% of vertebrates Save 1.4% and you save a good bit of world’s biodiversity

Myers et al., (2000) Biodiversity hotspots for conservation priorities. Nature 403: 853-858.

Conclusions Looks good, but… Tools of ecology help guide small, local decisions

At large scale, tools of ecology also offer guidance, but no easy answers.

Outlinefortoday  Componentsofaneffectivetalk

Apresentationabout givingapresentation LaurelSchaider 1.018/7.30JFinalLecture November20,2003

Components of presentation

• Visualguidelines • Review • Conclusions

Setting the stage

• Set the stage

• You can have bullet points

• Background

• to tell the audience what

• State the question/hypothesis

• you’re going to talk about

• Describe your approach

• but what might be better

• Sample data

• is a picture to really

• Conclusions

• set the stage

Picture of a fire along the side of a road. Removed for copyright restriction. See: http://www.nifc.gov/gallery/manter.html

ManterFireSequoiaNationalForestCalifornia (http://www.nifc.gov/gallery/manter.html

Howcanthisbeprevented?

www.nifc.gov-SequoiaNationalForestCalifornia

http://www.nfc.govgaer i / ll ymanter.html /

Whatarewedoingtorangelandgeneticdiversity?

http://www.nau.edu/~envsci/sisk/courses/env440/SCBS/andy.htm

Arewebeing affectedby environmental estrogens? news.bbc.co.uk/hi/english/business/newsid_610000/610046.stm

www.njeit.org/examples.htm

http://www.ecology.com/dr-jacks-natural-world/most-important-organism/

Introduction • Whyisyourtopicsignificant? • Whathaveotherpeoplestudiedaboutit? • Whatisnotknown?

ManterFire SequoiaNationalForestCalifornia (http://www.nifc.gov/gallery/manter.html

StatetheQuestion/Hypothesis • Whatisthemajorquestionorhypothesis youaretesting? • Youcanhave1or2or3,butnottoomany

Whatroledochelatedmetals playintotalmetaluptake?

Approach&methods Cells

• Discussapproach • Brieflyincludeimportantmethods

Forwardlight scatterdetector

Laser

–Siteselection –Novelexperimentaltechniques

DNA percell

–Unfamiliarconcepts

• Picturesareveryhelpfulhere! Prof. Chisholm

Pigmentfuorescence l detector

Hypothesizedresults

Methods • Growplants4-6weeks • 2-3daysexposuremetal-EDTA solutions total metal – GFAAS FeEDTA- & total EDTA HPLC, Nowack et al., 1996 Me-EDTA2- – HPLC Bedsworth & Sedlak, 2001

• Graphsarereallyhelpful • Tablescanbehardtoread • Justoneortwoexamples...Youdon’thave timetoshareallyourhypothesizeddata

Winogradsky data %with colorsin mud

%with bubbles

%black

Winogradsky data

Meat

100

100

50

No Meat

0

80

60

100 80 s e 60 l p m a s 40 %

Meat Nomeat

20 0 black

Potential further global emissions from fossil fuels (GtC) 659a -4000 b

Residence time of CO2 in the atmosphere (yr) 50 - 200 c

CO2 Storage Optionf Southern Ocean Fe-Fertilisation

Approx. Global Capacity (GtC) 152 i

Deep Ocean Injection or Diffusion Ocean Aquifers

> 1,000

>300m (4.1)n

100m-220q

Depleted Oil & Gas Reservoirs

Agro-forestry

Atmospheric CO 2 accumulation rate (GtC/yr) 3.3 ± 0.2 d ,h

Target reduction in atmospheric CO 2 over next 100 years (GtC) Approx. 850 e

Residence Time (years) Varies with durati on of ocean fertilisation 100-1000 o

Sequestration Rate (GtC/yr) 1.52 (100 year average)l

50-60m,r (4.7)s

Si te specific m

> 0.001t (not yet maximized)

180s

(8.2)r

Up to 1,000,000s

Site specific

50 -100 u (About 290 Mha suitable globally for this practice)

10v- 80i (Depends on land & water cost, & valu e of products) 40-60 s

> 100 (Depends on management strategy)

1.2s (2.2tC /ha-yr)w

Total Cost g

($/tC) 1-15 j 85k

Enhanced Oil Recovery

>16.6s

Coal-bed CH4

(a) 1.4 - 4.1 (b)18 -22 (c) 40 y

(a) - 55 (!) (b) 50 (c) 350-450s

Optimal rate to be determined

(3.9–7.7tC/ha -yr)s 0.4s

Up to 1,000,000s

Up to 1,000,000s

Site specific

Gl obal annual CO 2 avoidance & capture target (GtC/yr) 3.5 + [rise in emissions]

Ecological Other Benefits Risks Hypoxia, Stimulatesfish HABs, change production? in species composition Ecos yst em None disruption due to CO2 acidity p Groundwater None impact, leakage to bent hic zone Groundwater Extends value impact, land of reservoir site absidence, subsidence Introduction of Biofuels and alienspecies, ot her product s, monoculturing, wildlife habitat, land/water use watershed s conflicts management. Groundwater Increased oil impact, land recovery absidence, subsidence Low risk Recovery of methane

EffectsofexcessEDTA ) g ( t h g i e w y r d t o o h s r o t o o R

0.1

95

0.08 0.06

%water shoots

**

**

0.04 0.02 0

roots

control (45 M excess EDTA)

**

*

) % ( t n e 90 t n o c r e t a 85 w t o o h S

* ** 80 500 M 500 M excess excess EDTA+ EDTA Cu,Fe,Mn,Zn

bubb les

colors in mud

EffectsofexcessEDTA Deployment Status IRONEX I & II, SO IREE, and CARUSOfield experiments DOE Testing off Kona Island in 2001-2002? Commercial pilot at Sleipner in North Sea.

JI project in Scolel Te, Mexicox. Farm management in USAfor CO2. Commercial use in North Sea & West Texas s. Commercial pilots in New Mexico and Australia.

) g ( t h g i e w y r d t o o h s r o t o o R

0.1

95

0.08 0.06

%water shoots

**

0.04 0.02 0

roots

control (45 M excess EDTA)

**

) % ( t n e 90 t n o c r e t a 85 w t o o h S

* 80 500 M 500 M excess excess EDTA+ EDTA Cu,Fe,Mn,Zn

Concusions&Implcat l i ions • Tell themwhatyoutodthem l • Re-iteratewhyitmatters

Planningcontent

Generalhintsoneffectivevisuals

• Considerknowledgeofaudience

• Concise

• Considerwhatmakesaninterestingstory

• Font

• Askrhetoricalquestions

• Color

• Youcan’tsayeverythingthat’sinyour proposal!

Generalhintsoneffectivevisuals • Don’tusemorewordsthanarenecessary • Chooseafontstyleandsizethatwillallow youraudiencetoseethewordsclearly • Whilecolorscanbeveryuseful,choose carefullyanddon’tover-doit.

Bulletpoints

Bulletpoints •Watchoutforalignmentofbullets •Thereshouldbeaspacebetweenbulletand firstword •Andsecondlineshouldbealigned •Andthereshouldbespacebetweenpoints •Thiswillmakethewordseasiertoread •Butyoushouldn’thavethismanywordsinthe firstplace,thisismoreasanexample

Bewaretheflyingbullet

•Watchoutforalignmentofbullets

•Somepeoplelikethebulletpoints

•Thereshouldbeaspacebetweenbulletand firstword

•Tocomeflyinginone-by-one

•Andsecondlineshouldbealigned •Andthereshouldbespacebetweenpoints •Thiswillmakethewordseasiertoread •Butyoushouldn’thavethismanywordsinthe firstplace,thisismoreasanexample

•Thiscaninterestingandamusing •Butsometimesisdistracting •Pluspeoplesometimesliketohavetimeto readoverallthepointsattheirleisure

Thisisinsize40font

Fontswithoutserifsareeasiertoreadthanfontswithserifs. Serifsare thoselittlelineslikeyouhaveinTimesNewRomanfont.Thisisin ArialFontsize20.

Thisisinsize35font Thisisinsize30font Thisisinsize25font Thisisinsize20font Thisisinsize16font

Fonts without serifs are easier to read than fonts with serifs. Serifs are those little lines like you have in Times New Roman font. This is in Times New Roman Font size 20.

Thisisinsize12font Thisisin size 8font

Fonts without serifs are easier to read than fonts with serifs. Serifs are those little lines like you have in Times New Roman font. This is in Palatino Font size 20.

Colors can be used very effectively.

Of course, color choice depends on your background.

Contrastingcolors makea more dramaticeffectthan

Contrastingcolors makea more dramaticeffectthan

r eal ly sim il ar col ors, w hic h mi ght not sh ow up as different.

r eal ly sim il ar col ors, whic h mi ght not sh ow up as different.

Some colors show up better than others.

Some colors show up better than others.

Too man y col or s, w ell , ar e just t oo many col ors.

Too man y col or s, w el l, ar e j ust t oo many col ors.

Speakingofbackgrounds

Bewareofreallybusyortextured backgrounds

•Darkbackgroundswithlightwritingcanbereallynice

Thesecanbedstractng i i Andasomakethetexthardertoread l

•Problems: –Sometimeshardertomakehandouts –Wastesalotofinkifyouwanttophotocopy –Candarkenaroom

There are many pre-set options

Engagingtheaudience

Some are interesting

• Eyecontact

Some are distracting

• Pace

Choose carefully

•Content–Who’syouraudience?

biosphere ecosystem

PRACTICE!

community population organism

Organism

Population

Metabolisms:sourcesofC,energy,e-

Populationgrowth

heterotrophs

Intraspecificcompetition

photoautotrophsandchemolithoautotrophs

wolf

deer

wolf

moose

nutrients

deer light

grass

moose

nutrients

light grass

Community

Ecosystem

Interspecific competition

Productivity

Predation

Limiting nutrients

Food webs

Life

Surroundings

wolf

deer

wolf

moose

deer

nutrients

light

moose

nutrients

grass

light grass

Biosphere

Whatelseisecology?

Grassland wolf wolf

Biogeochemicalcycles deer deer

Climatechange

• Differentbiomes

moose moose

nutrients

–Tropicalecology,marineecology,etc.

light grass grass

• Differentorganisms CO2

O2

–Plants,microbes,animals

N

Tundra

Ocean

fox

fish fish

ferret

mouse

nutrients

copepod copepod light

• Evolutionaryecology shrimp shrimp

nutrients

moss

• Population&communityecology

light algae

Wanttolearnmore? DepartmentofOrganismic&Evolutionary Biology EvolutionofPlantLifeinGeologicTime BiologicalOceanography TropicalInsectSystematics GlobalChangeBiology TopicsinMarineBiology NatureandRegulationofMarineEcosystems ForestEcology

Ecologyisascience

Fundamentals of Ecology

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