Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator
Environmental contaminants are a continued threat to marine wildlife because they are globally dispersed, bioaccumulate in top predators, and can disrupt physiological pathways, thus leading to adverse health effects. For adult marine mammals, the main source of contaminants is through their diet, t...
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ftcdlib:qt37x1c8t5 2023-05-15T16:05:13+02:00 Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator Peterson, Sarah Elendil Hardee 184 2015-01-01 application/pdf http://www.escholarship.org/uc/item/37x1c8t5 http://n2t.net/ark:/13030/m5gt7w0d en eng eScholarship, University of California http://www.escholarship.org/uc/item/37x1c8t5 qt37x1c8t5 http://n2t.net/ark:/13030/m5gt7w0d public Peterson, Sarah Elendil Hardee. (2015). Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator. UC Santa Cruz: Ecology and Evolutionary Biology. Retrieved from: http://www.escholarship.org/uc/item/37x1c8t5 Ecology Toxicology Biology biomagnification ecotoxicology foraging ecology marine mammal oceanography Pacific Ocean dissertation 2015 ftcdlib 2016-04-02T19:16:42Z Environmental contaminants are a continued threat to marine wildlife because they are globally dispersed, bioaccumulate in top predators, and can disrupt physiological pathways, thus leading to adverse health effects. For adult marine mammals, the main source of contaminants is through their diet, therefore foraging behavior, including geographic location, foraging depth, and prey type, may exacerbate or mitigate contaminant exposure. Fluctuating body condition can also significantly affect contaminant concentrations in multiple tissues and thus temporally influence individual toxicological risk. My dissertation provides an extensive analysis of the assimilation of persistent organic pollutants (POPs) and mercury into the mesopelagic-foraging northern elephant seal. My research integrates foraging behavior (movements, diving, and stable isotopes), physiology (reproductive or molting state and measurements of general body condition), and demographics (age and sex), to understand how these factors influence contaminant dynamics. Northern elephant seals, Mirounga angustirostris, spend the majority of their lives at sea foraging in the mesopelagic (200 – 1000 m depths) North Pacific Ocean, hundreds to thousands of kilometers from the coastline of North America. Such remoteness creates challenges to understanding the ecosystem where they forage. However, elephant seal life history brings them to shore predictably twice each year for breeding and molting, at which time we can sample their tissues and attach or recover electronic tags to quantify movements and diving behavior. Every elephant seal I sampled had detectable concentrations of PCBs, PBDEs, organochlorine pesticides and mercury, demonstrating that POPs and mercury are pervasive in the food webs of northern elephant seals. For both POPs and mercury, I showed varying levels of bioaccumulation in elephant seals related to foraging behavior across a large region of the northeast Pacific, indicating that certain regions and depths pose a heightened exposure risk of contaminants to marine predators. However, the relationship between foraging behavior and contaminant bioaccumulation differed among individual compounds. Because predators integrate contaminants from their foraging areas, geographical variability in predator contaminant concentrations may be a useful indicator of the ecotoxicological risk of these contaminants to cryptic or threatened marine predators that live in deep ocean food webs of the North Pacific Ocean. Doctoral or Postdoctoral Thesis Elephant Seal Elephant Seals University of California: eScholarship Pacific |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Ecology Toxicology Biology biomagnification ecotoxicology foraging ecology marine mammal oceanography Pacific Ocean |
spellingShingle |
Ecology Toxicology Biology biomagnification ecotoxicology foraging ecology marine mammal oceanography Pacific Ocean Peterson, Sarah Elendil Hardee Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
topic_facet |
Ecology Toxicology Biology biomagnification ecotoxicology foraging ecology marine mammal oceanography Pacific Ocean |
description |
Environmental contaminants are a continued threat to marine wildlife because they are globally dispersed, bioaccumulate in top predators, and can disrupt physiological pathways, thus leading to adverse health effects. For adult marine mammals, the main source of contaminants is through their diet, therefore foraging behavior, including geographic location, foraging depth, and prey type, may exacerbate or mitigate contaminant exposure. Fluctuating body condition can also significantly affect contaminant concentrations in multiple tissues and thus temporally influence individual toxicological risk. My dissertation provides an extensive analysis of the assimilation of persistent organic pollutants (POPs) and mercury into the mesopelagic-foraging northern elephant seal. My research integrates foraging behavior (movements, diving, and stable isotopes), physiology (reproductive or molting state and measurements of general body condition), and demographics (age and sex), to understand how these factors influence contaminant dynamics. Northern elephant seals, Mirounga angustirostris, spend the majority of their lives at sea foraging in the mesopelagic (200 – 1000 m depths) North Pacific Ocean, hundreds to thousands of kilometers from the coastline of North America. Such remoteness creates challenges to understanding the ecosystem where they forage. However, elephant seal life history brings them to shore predictably twice each year for breeding and molting, at which time we can sample their tissues and attach or recover electronic tags to quantify movements and diving behavior. Every elephant seal I sampled had detectable concentrations of PCBs, PBDEs, organochlorine pesticides and mercury, demonstrating that POPs and mercury are pervasive in the food webs of northern elephant seals. For both POPs and mercury, I showed varying levels of bioaccumulation in elephant seals related to foraging behavior across a large region of the northeast Pacific, indicating that certain regions and depths pose a heightened exposure risk of contaminants to marine predators. However, the relationship between foraging behavior and contaminant bioaccumulation differed among individual compounds. Because predators integrate contaminants from their foraging areas, geographical variability in predator contaminant concentrations may be a useful indicator of the ecotoxicological risk of these contaminants to cryptic or threatened marine predators that live in deep ocean food webs of the North Pacific Ocean. |
format |
Doctoral or Postdoctoral Thesis |
author |
Peterson, Sarah Elendil Hardee |
author_facet |
Peterson, Sarah Elendil Hardee |
author_sort |
Peterson, Sarah Elendil Hardee |
title |
Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
title_short |
Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
title_full |
Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
title_fullStr |
Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
title_full_unstemmed |
Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
title_sort |
influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
http://www.escholarship.org/uc/item/37x1c8t5 http://n2t.net/ark:/13030/m5gt7w0d |
op_coverage |
184 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Elephant Seal Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals |
op_source |
Peterson, Sarah Elendil Hardee. (2015). Influence of foraging ecology and body condition on contaminant bioaccumulation in a top marine predator. UC Santa Cruz: Ecology and Evolutionary Biology. Retrieved from: http://www.escholarship.org/uc/item/37x1c8t5 |
op_relation |
http://www.escholarship.org/uc/item/37x1c8t5 qt37x1c8t5 http://n2t.net/ark:/13030/m5gt7w0d |
op_rights |
public |
_version_ |
1766401122395750400 |