Compound-specific Stable Isotopes of Amino Acids Reveal the Influence of Trophic Level and Primary Production Sources on Mercury Concentrations in Fishes from the Aleutian Islands, Alaska PDF Download
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Author: Michelle Trifari
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 0
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Book Description
Total mercury (THg) concentrations exceed thresholds of concern in some Steller sea lion (Eumetopias jubatus; SSL) tissues from certain portions of the Aleutian Islands, Alaska. Here, compound-specific stable isotope analyses (CSIA) of carbon in essential amino acids ([delta]13CEAA values) and nitrogen in AAs ([delta]15NAA values) in fish muscle tissue was applied to quantify the proportional contributions of primary production sources and trophic positions of eight prey species (n = 474 total) that are part of SSL diets. Previous THg analyses of fish muscle, coupled with additional monomethylmercury (MMHg) analyses of a subset of samples, substantiated previous findings that fishes from the west of Amchitka Pass, a discrete oceanographic boundary of the Aleutian Archipelago, have higher muscle THg concentrations relative to fishes from east of the pass. All fish muscle samples were analyzed separately for, both, CSIA-AA of carbon and nitrogen. The [delta]13CEAA values in fish muscle demonstrated that although most fishes obtained their EAAs primarily from algae, some species varied in the extent to which they relied on this primary production source. Certain [delta]15NAA values of the same fish samples indicated that trophic positions of fishes were higher from the west relative to the east of the pass for some species. Total Hg was positively correlated with bulk [delta]15N values, [delta]15N values of glutamic acid ([delta]15NGlu), and trophic positions. However, only trophic magnification slopes using [delta]15NGlu values indicated a higher rate of Hg biomagnification to the west of Amchitka Pass. Broad and species-level multiple linear regression models revealed that trophic position was the most important driver of fish muscle THg with a smaller amount of variation explained by other parameters, such as proportional contributions of primary production sources, fish body condition, and catch location. Collectively, results indicate that differences in fish trophic positions were the most consistent determinants of the higher fish THg concentrations to the west of Amchitka Pass. However, a higher rate of THg biomagnification to the west of Amchitka Pass may also play a role in the regional differences in fish muscle THg.
Author: Michelle Trifari
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 0
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Book Description
Total mercury (THg) concentrations exceed thresholds of concern in some Steller sea lion (Eumetopias jubatus; SSL) tissues from certain portions of the Aleutian Islands, Alaska. Here, compound-specific stable isotope analyses (CSIA) of carbon in essential amino acids ([delta]13CEAA values) and nitrogen in AAs ([delta]15NAA values) in fish muscle tissue was applied to quantify the proportional contributions of primary production sources and trophic positions of eight prey species (n = 474 total) that are part of SSL diets. Previous THg analyses of fish muscle, coupled with additional monomethylmercury (MMHg) analyses of a subset of samples, substantiated previous findings that fishes from the west of Amchitka Pass, a discrete oceanographic boundary of the Aleutian Archipelago, have higher muscle THg concentrations relative to fishes from east of the pass. All fish muscle samples were analyzed separately for, both, CSIA-AA of carbon and nitrogen. The [delta]13CEAA values in fish muscle demonstrated that although most fishes obtained their EAAs primarily from algae, some species varied in the extent to which they relied on this primary production source. Certain [delta]15NAA values of the same fish samples indicated that trophic positions of fishes were higher from the west relative to the east of the pass for some species. Total Hg was positively correlated with bulk [delta]15N values, [delta]15N values of glutamic acid ([delta]15NGlu), and trophic positions. However, only trophic magnification slopes using [delta]15NGlu values indicated a higher rate of Hg biomagnification to the west of Amchitka Pass. Broad and species-level multiple linear regression models revealed that trophic position was the most important driver of fish muscle THg with a smaller amount of variation explained by other parameters, such as proportional contributions of primary production sources, fish body condition, and catch location. Collectively, results indicate that differences in fish trophic positions were the most consistent determinants of the higher fish THg concentrations to the west of Amchitka Pass. However, a higher rate of THg biomagnification to the west of Amchitka Pass may also play a role in the regional differences in fish muscle THg.
Author: Christian Jeitner
Publisher:
ISBN:
Category : Dolly Varden (Fish)
Languages : en
Pages : 190
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Book Description
"Concerns about contaminants in fish have increased in recent years, especially in species consumed heavily in subsistence diets. Most studies of contaminants in Alaskan subsistence foods have focused on mainland Alaska not the Aleutian Islands. Several islands along the Aleutian Archipelago of Alaska have supported military bases which may be a source of pollution, and the proximity of the Aleutian chain to Eastern Asia may increase its susceptibility to atmospheric deposition of heavy metals. This study compares levels of arsenic, cadmium, chromium, lead, mercury and selenium in the egg, kidney, liver and muscle of Dolly Varden (Salvelinus malma) from Umnak, Adak, and Amchitka Islands in the Aleutian Chain of Alaska. I examined levels as a function of tissue, gender, collection site, and size. There were significant differences in the levels of metals as a function of tissue, with kidney having the highest levels of arsenic and cadmium, and kidney and liver having significantly higher levels of chromium and mercury than the other tissues examined. Selenium and arsenic in muscle and liver were highly correlated with both length and weight of fish. Arsenic and mercury in muscle were highly correlated with levels in liver, kidney and egg. There were few significant gender differences in metal concentrations, with females having higher levels of chromium in muscle and cadmium in kidney than males. However selenium in liver was higher in males than females. On Amchitka mean mercury levels were higher in both muscle (149 ppb; ng/g, wet weight) and liver (321 ppb) compared to fish from Adak and Umnak (muscle = 24 ppb and liver = 44 ppb). Dolly Varden collected from Cannikin Lake and Fox Lake on Amchitka were probably not sea run. This may explain the elevated mercury levels found in Dolly Varden from Amchitka Island. Landlocked Dolly Varden feed more heavily on smaller fish and fish eggs which places them at a higher trophic level than anadromous fish which primarily feed on amphipods. Selenium levels were highest in muscle (761 ppb) and liver (1,860 ppb) of fish caught in Cannikin Lake on Amchitka Island. Overall, concentrations of the metal contaminants in Dolly Varden were relatively low when compared with other studies on anadromous and marine fish from the region, and differences among collection sites may be due to trophic level differences between landlocked (Cannikin Lake) and sea-run Dolly Varden"--Leaves ii-iii.
Author: Jennifer C. Lehman
Publisher:
ISBN:
Category :
Languages : en
Pages : 192
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Author: Ryan Franklin Lepak
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Recent advancements in utilizing high precision isotope analysis allows us to trace sources of mercury (Hg) and processes it undergoes without the need of enriched isotope amendment. Here, we use total mercury (HgT) stable isotope ratios in fish, the lower food web, particulate matter, and water to unravel the linkages between bioaccumulation of MeHg and sources of Hg to fish from the Great Lakes and remote Alaska. Through the combination of multiple traditional Hg measurements and Hg stable isotopes, we identify sources of Hg to biota, but also quantify the impact of variables (such as dissolved MeHg concentrations, distribution coefficients, fish age) often absent in Hg isotope studies. This knowledge is critical to interpreting challenging fractionation patterns in fish. In choosing ecosystems absent of point source contamination, we are able to explore background conditions and infer novel processes (e.g. water column methylation) previously unrecognized by applying sensitive isotopic tracers (e.g. [capital delta]200Hg). We studied ecosystems absent of significant sedimentary MeHg fluxes, and find evidence contrary to the assumption that sediments accurately predict Hg sources to fish. To do so, we use carefully chosen ecosystems and employ the use of intensive water column profiling. With the first use of a biological archive, using Hg stable isotope analysis we probed the impact of Hg mitigation strategies on both sediments and fish, and find that fish respond to Hg mitigation much more rapidly than previously recognized. This, paired with the first lower food web exploration using Hg stable isotopes, supports the notion that sediment Hg and fish Hg concentrations are decoupled. Recently deposited atmospherically-sourced Hg is shown to be highly bioavailable, and fish respond rapidly to perturbations to atmospherically-sourced Hg. Finally, energy pathways (source C, N and diets) are important for accurately interpret Hg source pathways and provides corroborating results to go along with the Hg isotope results. These tracers allow us to expand our understanding of bioaccumulative Hg pathways to biota. Together, multi-isotope tracing allows us for differentiation between changing Hg-source portfolios in biota and shifting diets in fish, information highly important to resource managers.
Author: Jason B. West
Publisher: Springer Science & Business Media
ISBN: 9048133548
Category : Science
Languages : en
Pages : 495
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Book Description
Stable isotope ratio variation in natural systems reflects the dynamics of Earth systems processes and imparts isotope labels to Earth materials. Carbon isotope ratios of atmospheric CO2 record exchange of carbon between the biosphere and the atmosphere; the incredible journeys of migrating monarchs is documented by hydrogen isotopes in their wings; and water carries an isotopic record of its source and history as it traverses the atmosphere and land surface. Through these and many other examples, improved understanding of spatio-temporal isotopic variation in Earth systems is leading to innovative new approaches to scientific problem-solving. This volume provides a comprehensive overview of the theory, methods, and applications that are enabling new disciplinary and cross-disciplinary advances through the study of "isoscapes": isotopic landscapes. "This impressive new volume shows scientists deciphering and using the natural isotope landscapes that subtly adorn our spaceship Earth.", Brian Fry, Coastal Ecology Institute, Louisiana State University, USA "An excellent timely must read and must-have reference book for anybody interested or engaged in applying stable isotope signatures to questions in e.g. Anthropology, Biogeochemistry, Ecology, or Forensic Science regarding chronological and spatial movement, changes, or distribution relating to animals, humans, plants, or water.", Wolfram Meier-Augenstein, Centre for Anatomy & Human Identification, University of Dundee, UK "Natural resources are being affected by global change, but exactly where, how, and at what pace? Isoscapes provide new and remarkably precise answers.", John Hayes, Woods Hole Oceanographic Institution, USA "This exciting volume is shaping a new landscape in environmental sciences that is utilizing the remarkable advances in isotope research to enhance and extend the capabilities of the field.", Dan Yakir, Weizmann Institute of Science, Israel
Author:
Publisher:
ISBN:
Category : Steller's sea lion
Languages : en
Pages : 112
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Author: Elżbieta Kalisińska
Publisher: Springer
ISBN: 3030001210
Category : Science
Languages : en
Pages : 708
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Book Description
The population explosion that began in the 1960s has been accompanied by a decrease in the quality of the natural environment, e.g. pollution of the air, water and soil with essential and toxic trace elements. Numerous poisonings of people and animals with highly toxic anthropogenic Hg and Cd in the 20th century prompted the creation of the abiotic environment, mainly in developed countries. However, the system is insufficient for long-term exposure to low concentrations of various substances that are mainly ingested through food and water. This problem could be addressed by the monitoring of sentinels – organisms that accumulate trace elements and as such reflect the rate and degree of environmental pollution. Usually these are long-lived vertebrates – herbivorous, omnivorous and carnivorous birds and mammals, especially game species. This book describes the responses of the sentinels most commonly used in ecotoxicological studies to 17 trace elements.
Author: Jochen Hoefs
Publisher: Springer Science & Business Media
ISBN: 3662033771
Category : Science
Languages : en
Pages : 333
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Book Description
Stable Isotope Geochemistry is an introduction to the use of stable isotopes in the fields of geoscience. It is subdivided into three parts: - theoretical and experimental principles; - fractionation mechanisms of light elements; - the natural variations of geologically important reservoirs. In this updated 4th edition many of the chapters have been expanded, especially those on techniques and environmental aspects. The main focus is on recent results and new developments. For students and scientists alike the book will be a primary reference with regard to how and where stable isotopes can be used to solve geological problems.
Author: Carmel Mothersill
Publisher: Springer Science & Business Media
ISBN: 1402063334
Category : Science
Languages : en
Pages : 483
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Book Description
Ecotoxiclogical risk from multiple stressors covers any situation where org- isms are exposed to a combination of environmental stressors. These include physical and chemical pollutants as well as other stressors such as parasites and environmental impact (e. g. , climate change or habitat loss). The combi- tion of stressors can result in increased risk to organisms (either additive or synergistic effects) or decreased effects (protective or antagonistic effects). The multiple stressor challenge is an international, multi-disciplinary problem requiring an international, multi-disciplinary approach. The c- rent approach to multiple stressors is to examine one stressor at a time and assume additivity. Little work has been done on combinations of stressors such that potential interactions can be determined. The problem is very complex. Multiple stressors pose a whole spectrum of challenges that range from basic science to regulation, policy and gove- ance. The challenges raise fundamental questions about our understanding of the basic biological response to stressors, as well as the implications of those uncertainties in environmental risk assessment and management. In addition to the great breadth, there is also great depth in the research ch- lenges, largely due to the complexity of the issues. From a basic science point of view, many of the mechanisms and processes under investigation are at the cutting edge of science — involving new paradigms such as genomic ins- bility and bystander effects.
Author: F Stuart Chapin III
Publisher: Springer Science & Business Media
ISBN: 0387216634
Category : Science
Languages : en
Pages : 449
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Book Description
Features review questions at the end of each chapter; Includes suggestions for recommended reading; Provides a glossary of ecological terms; Has a wide audience as a textbook for advanced undergraduate students, graduate students and as a reference for practicing scientists from a wide array of disciplines
