Biomagnification in Marine Ecosystems By Angela Leemhuis Hansen
Biomagnification •
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Xenobi Xenobioti oticc compou compounds nds –
POPs and others
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Properties
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Current events
Bioaccumulation –
Biomag Biomagnifi nifica catio tion n vs.
bioconcentration –
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Contaminant load: Effects
Different foodwebs Goerke, Goerke, et al. al. 2004 Biomagnifi Biomagnificatio cation n in the Antarctic Foodweb
Xenobiotic compounds •
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From the greek xenos ―stranger‖ and biotic ―related to living beings‖ A chemical chemical (natural or man-made) which is found in an organism, but not normally produced or expected to be there. –
Persistent organic pollutants (POPs)
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Some heavy metals (Hg, Pb, etc.)
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Heavy isotopes ( 14C, 15N, etc.)
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Natural toxins (phytoplankton toxins)
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Alien hormones (sewage exposure)
Persistent Organic Pollutants •
Recalcitrant: Compounds which persist in the environment and increase in concentrations with time.
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Ubiquitous: Widespread, semi-volatile, found everywhere.
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Lipophilic: Dissolves in, or has an affinity for lipids. Higher Higher trophic trophic levels levels have more lipids. lipids. Hydropho Hydrophobic. bic.
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High fugacity: Ability to move from one compartment to another, another, estimated with the octanol-water partition coefficient (K ow) or air (K OA).
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Toxic: High molecular mass, endocrine disrupters.
Stockholm Convention on POPs •
1995: The Governing Council of the United Nations Environment Programme (UNEP) called for global action on "chemical substances that persist in the environment, bio-accumulate through food webs, and pose a risk of causing adverse effects to human health and the environment".
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Intergovernmental Forum on Chemical Safety (IFCS) and the International Programme on Chemical Safety (IPCS) prepared an assessment of the 12 worst offenders.
2001-2004: Negotiations completed on 23 May 2001 in Stockholm. Came into force on 17 May 2004. Co-signatories agreed to outlaw nine of the dirty dozen doz en chemicals, limit the use of DDT, DDT, and curtail the production of dioxins and furans.
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2009: Nine additional POPs were added on 8 May 2009.
―The Dirty Dozen‖ Aldrin Chlordane DDT Dieldrin Endrin HCB Heptachlor Mirex Toxaphene PCBs Dioxins Furans www.epd.gov.hk
The Ocean: The Sink full of Soup •
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The ultimate destination for most persistent anthropogenic substances Substances with long residence times can cause serious harm to biota Substances can interact: –
Plastics are known to adsorb hydrophobic pollutants (Moore, 2008)
Not everything in the ocean belongs belon gs there! Plastic bags are particularly troublesome.
Bioaccumulation •
The upta uptake ke of a xenobiot xenobiotic ic compound compound by by an organism organism from the abiotic abiotic environment environment and biotic environments (all sources). –
Bioconcen Bioconcentratio tration n is uptake uptake directl directly y from the abiotic abiotic environmen environmentt (surrounding (surrounding water), water), resulting resulting in a higher concentration in the organism. This is the most common process for marine organisms up to and including fish (water breathing) (Gray,2002).
Water breathing animals from phytoplankton to inverts to fish can be affected by contaminants in the water, sediments and in their food.
Bioaccumulation –
Biomagnification is uptake from food to the consumer, consumer, resulting in a higher concentration in the consumer. consumer. This is clearly shown as the only route for air-breathing marine animals such as birds and marine mammals (Gray, 2002).
http://farm1.static.flickr.com/118/296212100_f12a51442a.jpg
http://neveryetmelted.com/wp-images/LeopardSeal.jpg
http://topnews.in/law/files/Whale-Eating-Whale.jpg
Air breathing animals are affected affecte d primarily by contaminants in their food.
Contaminant Load •
Determined by:
http://romepointseals.org/Blubber%20Crop.jpg
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Rate of uptake, metabolism and elimination
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Affecte Affected d by trophic trophic level, level, environme environmental ntal
More blubber can mean more toxic contaminants stored!
conditions, specie, size/lipid content and life history traits –
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Chemical qualities of the contaminant ( K OW and K OA).
Deleterious effects (sub-lethal and lethal): –
Reproduction (impairment, reduced success)
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Development Development (weakness, endocrine disruption) disruption)
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Immune system (stress, infection, cancer, death)
POPs accumulate in feathers, eggs, milk, liver, liver, kidney and fat storage/blubber (high lipid content).
Biomagnification in Different Different Foodwebs Foodwebs Ecosystems close to POP sources show the highest environmental levels of POPs and the highest concentrations in their resident organisms. http://www.jazzhostels.com/blog/wp-content/gal http://www.jaz zhostels.com/blog/wp-content/gallery/skyline/new lery/skyline/new-york-city-skyline.jpg -york-city-skyline.jpg
BUT
Due to the semi-volatile, ubiquitous nature of POPs they are now found EVERYWHERE! EVERYWHERE!
South to North Pacific Tanabe, 2002: Fig. 5. PCBs concentrations in mammals and birds collected from Japan and nearby seas.
Tanabe, 2002: Fig. 9. Comparison of toxicity equivalents (TEQ) values (pg/g fat weight) of dioxins dioxins and related compounds in humans and wildlife.
http://i.dailymail.co.uk/i/pix/2009/10/09/ http://i.dailym ail.co.uk/i/pix/2009/10/09/article-1219251-06C2AD22000005DCarticle-1219251-06C2AD22000005DC-653_634x381_popup.jpg 653_634x381_popup.jpg
Location, location, location. You’re not just
Arctic Foodweb
http://www.greenfacts.org/en/arctic-climate-change/figtableboxes/arctic-marine-food-web.htm
Arctic Foodwebs Kelly, et al. 2007 Fig. 1. Relationship between observed tissue residue concentrations (ng·g – 1 lipid equivalent equivalent)) and and trophic trophic level for PCB 153 (a high K OW, high K OA compound) and ß-HCH (a low K OW, high K OA compound) in Arctic organisms organisms of the piscivorous (A), terrestrial (B), and marine mammalian ( C) food webs. Data represent geometric means ± 1 SD.
Arctic Foodweb
http://www.alaska-in-pictures.com http://ww w.alaska-in-pictures.com/gray-whale-carcass-w /gray-whale-carcass-with-polar-bears-north-slope-alaska-6728-pictures.htm ith-polar-bears-north-slope-alaska-6728-pictures.htm
Antarctic Foodweb Unique environment: •
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Remoteness, proves the persistence and longrange transport of POPs. With the absence of point emissions or of river input to the Southern Ocean, contaminants found in fauna reflect global pollution levels, and recent uses in the southern hemisphere. Few studies done for POPs over a time-series.
Antarctic Foodweb •
Goerke, et al. 2004 –
Sampled from 1986-2000
Most recalcitrant POPs: HCB, p,p'-DDE, Mirex, PCB, chlordane
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11 species: 2 inverts (krill and squid), 6 fish (benthic and surface), 1 bird (Adelie penguin), and 2 pinnipeds (Weddell and elephant seals) Samples were normalised to lipid content.
Temporal trend results Goerke, et al. 2004 Fig. 2. Concentrat Concentrations ions of organochlorine compounds in livers of three Antarctic fish species from 1987 and 1996. Heavy lines indicate statistically statistically significant differences (t test, P =0.05). =0.05). Bars represent standard errors of the means.
Concentration patterns in organisms Fig. Fig. 3. Concen Concentra tratio tion n patterns of organochlorine compounds in Antarctic species of different trophic levels. Bars represent means and standard deviations. Bold numbers indicate biomagnification factors in relation to krill. (I) Herbivore, (II) 1st level carnivore, (III) 2nd level carnivore.
Antarctic Foodweb •
Results: Goerke, et al. 2004 –
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Benthic and fish feeding fish had higher contaminant loads for most POPs than krill feeders (vertical transport of POPs from the surface to the benthos accumulating in the sediments). Increase in contaminant load over time observed (due to redistribution and recent uses in the southern hemisphere) Mirex Mirex and chlor chlordane dane most increas increased ed
Antarctic Foodweb •
Goerke, et al. 2004 –
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Biomagnifi Biomagnificatio cation n observed observed with increasing increasing strength strength in mackerel mackerel icefish, icefish, adelie adelie penguins, penguins, and both pinnipeds. The pinnip pinnipeds eds showed showed high high bioma biomagni gnific ficati ation on for all POPs except HCB (special ( special metabolic ability suspected), not seen in cetaceans. Biomonitori Biomonitoring ng should include include multiple multiple taxa taxa POPs in in antarctic antarctic fish were were 1-2 orders orders of of magnitude lower than northern hemisphere fish POPs rising here...diminishing there.
―Biomagnification occurs when contaminants that don’t easily degrade increase with each link of a food chain. In seawater, these persistent molecules stick to small particles and phytoplankton. Small fish eat the phytoplankton, but the contaminants can’t be broken down and are absorbed, intact, by the fish. When small fish are eaten by larger predators, the process repeats — again again and again, up the food chain. Each subsequent subsequent predator receives a higher dose than the previous one. Animals at the top of the food chain, such as dolphins, receive the most concentrated dose of these contaminants with every meal.‖ (Illustration by E. Paul Oberlander, Woods Woods Hole Oceanographic Institution)
Questions?
References •
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Chiou, C.T. 1985 Partition coefficients of organic compounds in lipid-water systems and correlations correlations with fish bioconcentration bioconcentration factors. Environ. Sci. Technol. 19: 57-62. Goerke, H., Weber, K., Bornemann, H., Ramdohr, S., Ploetz, J. 2004. Increasing levels and biomagnification biomagnification of persistent organic pollutants (POPs) in Antarctic biota. Marine Pollution Bulletin. 48: 295-302. Gray, J.S. 2002. Biomagnification in marine systems: systems: the perspective perspective of an ecologist. Marine Pollution Bulletin. 45: 46-52 Kelly, B.C., Ikonomou, M.G., Blair, J.D., Morin, A.E., Gobas, F.A.P.C. 2007. Food web-specific biomagnification of persistent organic organic pollutants. Science. 317: 236239. Moore, C.J. 2008. Synthetic polymers in the marine environment: A rapidly increasing, long term threat. Environmental Science. 108: 131-139. Tanabe, S. 2002. Contamination and toxic effects effect s of persistent endocrine disrupters in marine mammals and birds. Marine Pollution Bulletin. 45: 69-77.
Notes for presentation Introduction Today we will be discussing the the biomagnification of compounds in the marine environment, environment, the significance and intricacies intricacies of the process, the effects on biota. First we will cover the types of compounds that biomagnify, called xenobiotic compounds, their properties and some current events that have made them of such interest to the scientific community now. Then we will cover the differences of bioaccumulation, bioaccumulation, bioconcentration and biomagnifications biomagnifications (yes, they are three different things). We will briefly discuss contaminant loads and their effect on an organism’s health. Then we will take a look at biomagnifications trends in different foodwebs. And finally we will take a look at a paper by Helmut Goerke, et al., 2004, Increasing levels and biomagnifications of persistent organic pollutants in Antarctic biota.
Xenobioti Xenobioticc compound compoundss xeno, meaning stranger or foreigner, and biotic, meaning related to living beings. The word xenobiotic comes from the greek xeno, Xenobiotic compounds are any chemical chemical or element which is found in an organism, but which is not normally normally produced by it, or expected to be there. Xenobiotic compounds include persistent persistent organic pollutants which are anthropogenic (man-made), some heavy metals such as mercury and lead, heavy isotopes such as 15 N and 14C, natural toxins that build-up in a predator from eating it’s prey such as phytoplankton toxins, and even alien hormones which refers to human hormones found in fish that live downstream from sewage outlets. We will be focusing on persistent organic pollutants, or POPs.
Persistent organic pollutants Persistent organic pollutants are recalcitrant, which means that they persist in the environment and increase in concentration over time. They are ubiquitous, which means they are widespread across the plant and within all the oceans. This is a function of their persistence in the environment and that many POPs are semi-volatile, which mean they easily evaporate and move with global air-circulation patterns. They are lipophilic, which means they dissolve in lipids, have an affinity for lipids, and are hydrophobic, so they won’t dissolve in water. Instead they will stick to other things they come in contact with in th e water column (particulate matter, organisms, etc.). They have a high fugacity, or ability to move from one compartment to another (across lipid layers), and this is expressed with the octanol-water and octanol-air coefficients. We will see more about this later. And lastly, due to their unnaturally high molecular masses they are generally very toxic to organisms, and can act as endocrine disrupters.
Stockholm Convention on POPs In 1995 the governing council of the United Nations Environment Programme (UNEP) called for global action on "chemical substances substances that persist in the environment, bio-accumulate through food webs, and pose a risk of causing adverse effects to human health and the environment". In response the Intergovernmental Intergovernmental Forum on Chemical Safety (IFCS) and the International Programme on Chemical Safety (IPCS) prepared an assessment assessment of the 12 worst offenders, which we now call the “dirty dozen”. Negotiations dozen”. Negotiations were completed completed on 23 May 2001 in Stockholm, to come into force on 17 May 2004, and the co-signatories co-signatories agreed to outlaw nine of the dirty dozen chemicals, limit the use of DDT, and curtail the production of dioxins and furans. On May 8, 2009 nine additional POPs were added to the list, and countries are still negotiating over them.
The Dirty Dozen This is an educational brochure from the government of Hong Kong explaining POPs, the Stockholm convention, and how Hong Kong is in the forefront when it comes to adhering to the Stockholm Convention and being environmentally environmentally friendly. I found it interesting and amusing.
The Ocean: The sink full of soup Biomagnification Biomagnification has been observed in the terrestrial terrestrial environment for much longer than in the marine environment. environment. Actually, some scientists originally thought biomagnifications would not occur in marine systems because of the dilution of compounds, and the openness openness of marine foodwebs. Unfortunately for the ocean this has turned out to not be true. The ocean is the ultimate sink for just about all man-made compounds, and because because we make things to last, they tend to have long residence times in the ocean. Some even interact. Seabird research has shown a correlation between PCB levels in birds and the amount of plastic they have in their stomachs. Plastic polymers, which have a very long residence time in the water column, are now known to adsorb hydrophobic pollutants (POPs) like little sponges. When the plastic is consumed by the less-picky eaters eaters of the ocean (which is most of them) they are also exposed to the toxins stuck to the plastic. Bioaccumulation Bioaccumulation Bioaccumulation is the uptake of xenobiotic compounds by an orga organism nism from all sources in its environment. environment. From the water directly, as well as from food sources. Bioconcentration is the passive uptake from the surrounding water only, which occurs readily across respiratory surfaces of water-breathing invertebrates and vertebrates. Elimination also occurs across these respiratory surfaces, surfaces, but generally decreases in rate with increasing organism size. The lipid content of the organism is also a factor in retention.
Biomagnification is the uptake from food only, when the consumer consumer ends up with a higher concentration concentration of the compound than was found in the prey. This is the only pathway pathway for air-breathing marine animals to accumulate compounds. compounds. Here ar some pictures of air-breathing marine wildlife: a bird eating a fish, a leopard seal eating a penguin, and an orca eating a seal.
Contaminant load Contaminant load is the over-all concentrations of contaminants, such as POPs, in an organism. It is determined by rates of uptake, metabolism metabolism and elimination of the organism. Also, life history traits such such as life-span, size, trophic level, species, lipid content, and environmental conditions. The chemical properties of the contaminants are also important. The detrimental effects of contaminants are many. Reproductive health and success are reduced, development can be affected by endocrine disruption or reduced fitness. Immune impairment is a common side-effect with increased stress levels, disease and infection incidence, cancer cancer and even death. POPs do not collect evenly within an organism, they tend to gather in lipid rich parts of the body (blubber/fat deposits, liver, kidney), and are even offloaded (feathers, eggs, milk, offspring).
Biomagnification in different foodwebs POPs are highest in concentration concentration closest to their sources, but there is not truly pristine environments left. They are found everywhere now. Observe the trends in the POP concentration data from Tanabe, 2002 off the coast of Japan and nearby seas. Observe the difference differencess between the piscivorous, terrestrial and marine mammal food webs in the Arctic, by Kelly, et al. 2007. Fin whales, a stork, and polar bears eating. The Antarctic foodweb is unique because there is no near-by sources of pollution. POPs found here prove the persistence and long-range transport of them. There are also few studies investigating POP levels in the Antarctic.
Goerke, et al. 2004 The Antarctic foodweb foodweb biomagnifications biomagnifications study of eleven different different species: krill, squid, six six types of fish, the adelie penguin, weddell seals and elephant elephant seals. Samples were taken from 1986 to 2000, and normalized normalized to lipid content so that the POP levels found would be comparable. Only the most recalcitrant POPs were tested for: HCB, DDT, Mirex, PCB and chlordanes.
Temporal trends can be seen here, with Mirex, and chlordane metabolites having the most increase with time in these three fish species. Different POP concentrations concentrations were found in different species: species: see the trends in HCB and DDT from krill up to weddell seals. Benthic and fish feeding fish were found to have higher contaminant loads than krill feeder, this probably has to do with the vertical transport of POPs to the seafloor, where they accumulate in the sediments. There was an increase in contaminant levels observed over time in Antarctica, demonstrating the increased use of POPs in the Southern hemisphere hemisphere and the redistribution of old POPs from other regions. regions. Mirex and chlordane were both the most increased, and they are known to be in current use in the Southern hemisphere. Conclusions: Biomagnification Biomagnification was observed observed in the foodweb. foodweb. Biomonitoring Biomonitoring should include more than one one taxa for each trophic level due to differences in elimination abilities. POP levels levels in the Antarctic are 1-2 orders of magnitude lower than in the Northern hemisphere, but they are increasing, while in the Northern hemisphere levels are decreasing.
Conclusion So, to recap, in simple terms, “ Biomagnification occurs when contaminants that don’t easily degrade increase with each link of a food chain. In seawater, these persistent molecules stick to small particles and phytoplankton. Small fish eat the phytoplankton, but the contaminants contaminants can’t be broken down and are absorbed, intact, by the fish. When small fish are eaten by larger predators, the process repeats — repeats — again again and again, up the food chain. Each subsequent predator receives a higher dose than the previous one. Animals at the top of the food chain, such as dolphins, receive the most concentrated dose of these contaminants with every meal.” (Woods Hole Oceanographic Institution) Biomagnification is of most significance significance in foodwebs with air-breathing constituents; but as we saw from Goerke, it is observed in water-breathing benthic fish as well.
Questions?
