Download or read book The Effects of Fish Community Complexity on Mercury Bioaccumulation in Lake Food Webs Supporting Brook Trout Salvelinus Fontinalis written by Monica Lynn Darlene Finley and published by . This book was released on 2013 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Effects of Watershed Acidification on the Speciation and Bioaccumulation of Mercury in Brook Trout Salvelinus Fontinalis at the Bear Brook Watersheds Maine USA written by Michael W. Powell and published by . This book was released on 1997 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury in Fish written by Collin Aaron Eagles-Smith and published by . This book was released on 2006 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury in Fish Bed Sediment and Water from Streams Across the United States 1998 2005 written by Barbara C. Scudder and published by DIANE Publishing. This book was released on 2010-08 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report on how mercury (Hg) was examined in top-predator fish, bed sediment, and water from streams that spanned regional and national gradients of Hg source strength and other factors thought to influence methylmercury bioaccum. Sampled settings include stream basins that were agr¿l, urbanized, undeveloped, and mined. Predator fish were targeted for collection, and composited samples of fish were analyzed for total Hg (THg), as most of the Hg found in fish tissue is MeHg. Samples of bed sediment and stream water were analyzed for THg, MeHg, and characteristics thought to affect Hg methylation, such as loss-on-ignition and acid-volatile sulfide in bed sediment, and pH, dissolved organic carbon, and dissolved sulfate in water. Illus.
Download or read book The Fate of Atmospherically Deposited Mercury in Mountain Lake Food Webs and Implications for Fisheries Management written by and published by . This book was released on 2019 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mountain lakes are an iconic feature of the landscape in the Mountain West. They hold significant ecological and cultural value, and are important sentinels of environmental change. Despite their pristine image, these remote waterbodies are subjected to numerous anthropogenic stressors. Mountain lakes are naturally fishless systems, but historical fish stocking has led to major changes in mountain lake food web structure, including declines of resident amphibians, large-bodied zooplankton, and emergent insect populations. Atmospherically deposited contaminants, such as mercury, can accumulate in mountain lake food webs, leading to relatively high levels in the fish relative to the water. Managing for these stressors is difficult, because although fish stocking causes ecological problems, and mercury bioaccumulation poses human health risks, the cultural value of angling remains important. The goal of this dissertation was to better understand the issues of fish stocking and mercury bioaccumulation in a socioecological context: from the importance of trophic dynamics for mercury bioaccumulation in mountain lake fish, to the implications of fish stocking and mercury bioaccumulation for mountain lake management. In Chapter 2, I identified the ecological, limnological, and landscape-level indicators of mercury bioaccumulation in mountain lake food webs in order to inform better ecosystem management. In Chapter 3, I conducted an experiment to test if fatty acid stable isotopes can partition benthic and terrestrial prey sources in fish in a simplified mountain lake food web, in hopes of providing a more informative tool for future food web studies. In Chapter 4, I used intercept surveys to determine the public perceptions of mountain lake fisheries management in two national parks, and assess the risk mercury may pose to mountain lake anglers by determining fish consumption habits. This dissertation provides a unique set of tools that advance our understanding of food web dynamics and mercury bioaccumulation in mountain lakes, as well as the social value of these ecosystems. My results suggest that the most effective way to protect the health of mountain lakes and their visitors will be for managing agencies to collaborate with scientists and angling groups when making fisheries management decisions, and to invest in outreach about both the ecological and toxicological implications of fish stocking and mercury bioaccumulation in mountain lakes. The use of such socioecological research approaches is becoming progressively more important, as the threats of climate change and unstable regulatory protections for mountain ecosystems increase.
Download or read book Mercury Hazards to Fish Wildlife and Invertebrates written by Ronald Eisler and published by . This book was released on 1987 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Concentrations in Brook Trout and White Perch from Kejimkujik National Park Nova Scotia written by André D'Entremont and published by Halifax, N.S. : Parks Canada, Atlantic Region. This book was released on 1998 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examines fillet mercury levels in brook trout (Salvelinus fontinalis) and white perch (Morone americana) collected from water bodies in Kejimkujik National Park. Mercury levels found in these species, important components of the local recreational fishery, are compared to those observed in other North American studies and to Health Canada guidelines regarding safe consumption of fish. Correlations are identified between total mercury concentrations and fish age, length, and weight. Differences in mean mercury concentrations among sampling locations are also noted, and possible sources of the mercury contamination are discussed.
Download or read book Mercury Bioaccumulation in Remote Subalpine Lakes written by Adam Pfleeger and published by . This book was released on 2015 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury (Hg) contamination is a global conservation threat to freshwater ecosystems, detected in even the protected lakes of Olympic National Park (Washington, USA). Although considered some of the most remote and pristine US ecosystems, these lakes are currently subject to multiple environmental stressors, including climate change and fish introductions; adding contaminants, such as Hg, could exacerbate the effects of these stressors on native species. Amphibians are undergoing large worldwide declines, which include declines in protected areas, such as our National Parks. Our goal is to better understand the effect of historically stocked fish in Olympic National Park on native amphibian Hg bioaccumulation. To minimize the need for lethal sampling of this already threatened group, we first examine how Hg concentrations in non-lethally sampled amphibian tissues correlated with whole-body Hg concentrations, depending on species and the different type of non-lethal tissue sample used. Second, we aimed to understand how a food web altered by fish impacted Hg bioaccumulation in native species. We measured Hg and stable isotopes of carbon and nitrogen in organisms across trophic levels from 18 subalpine lakes. We detected small shifts in salamander food web indices and minor changes to salamander Hg concentration associated with the presence of fish. Importantly, we found increased mercury trophic magnification slopes in lakes with fish compared to fishless lakes. This research provides evidence that historic fish introductions can elevate mercury exposure in pristine ecosystems compared to natural fishless lakes.
Download or read book Ecosystem Responses to Mercury Contamination written by Reed Harris and published by CRC Press. This book was released on 2007-03-05 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: As rising levels of mercury in the environment pose an increasing threat of toxicity to humans and wildlife, several laws already call for industries to reduce mercury emissions at the source. Ecosystem Responses to Mercury Contamination: Indicators of Change outlines the infrastructure and methods needed to measure, monitor, and regulate the conce
Download or read book Thermal Stratification of Dilute Lakes written by Carl L. Schofield and published by . This book was released on 1993 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Bioaccumulation in Fishes from Subalpine Lakes in the Wallowa whitman National Forest Northeastern Oregon and Western Idaho written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-03 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury (Hg) is a globally distributed pollutant that poses considerable risks to human and wildlife health. Over the past 150 years since the advent of the industrial revolution, approximately 80 percent of global emissions have come from anthropogenic sources, largely fossil fuel combustion. As a result, atmospheric deposition of Hg has increased by up to 4-fold above pre-industrial times. Because of their isolation, remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited Hg through freshwater food webs, as well as for evaluating the relative importance of Hg loading versus landscape influences on Hg bioaccumulation.
Download or read book Long term Changes to Food Web Structures and Mercury Biomagnification in Three Large Inland North American Lakes written by John Poulopoulos and published by . This book was released on 2013 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous anthropogenic disturbances have occurred in large lakes over recent decades. These may alter concentrations of the biomagnifying contaminant mercury (Hg) in fish, but long-term impacts of disturbances on Hg trophodynamics are poorly understood. Elemental analyses of archived museum ichthyology specimens could be used to study historical, pre-disturbance fish food webs, but there is uncertainty about effects of chemical preservatives on the results of such analyses. In this thesis, long-term preservation effects were studied, and archived fish were used to reconstruct historical food webs and Hg trophodynamic patterns in three large North American lakes, Nipigon, Simcoe and Champlain. After 24 months of formalin/ethanol preservation, fish muscle delta-15N and delta-13C had average changes of +0.4 [per mille] and -0.9 [per mille], respectively. Shifts in mean Hg concentration was +5 % after 12 months. A suite of 26 other elements analyzed over 24 months showed consistent responses to preservation, usually involving an increase in concentration immediately following preservation. In the second phase of the thesis, stable isotope and Hg analyses were performed on archived and modern fish from the study lakes, dating to the 1920s-60s and 2006-7, respectively. Trophic relationships were often relatively stable over time, but stable isotope metrics revealed a decrease in Lake Nipigon delta-15N range and less pelagic feeding among Lake Simcoe pumpkinseed and yellow perch. In Lake Champlain, the re-introduction of lake trout in recent decades did not have a major effect on overall food web dimensions. Significant Hg biomagnification factors were found in 1920s and 2006-7 Lake Nipigon (which were not statistically distinguishable from each other) and 2006 Lake Champlain. These biomagnification factors ranged from 0.09 to 0.17, which is within the range found in other studies globally. Archived fish and government monitoring records indicated that fish Hg concentrations decreased in Lakes Simcoe and Champlain since historical periods, but remained similar or increased in Lake Nipigon. This thesis confirms the utility of archived fish for elemental analyses. It highlights the risks of Hg contamination and food web change that may be faced by remote lakes, and it provides evidence for relatively stable Hg biomagnification rates in large lakes.
Download or read book Legacy Contaminants in Brook Trout from Remote New Brunswick Lakes written by Meghan P. Fraser and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dichlorodiphenyltrichloroethane (DDT) and mercury are legacy contaminants that are persistent in the environment for decades or longer. They may impact food webs through bioaccumulation, biomagnification, and chronic toxic effects in exposed biota. DDT was applied aerially on large scales to the conifer forests in north-central New Brunswick between 1952 and 1968 for pest control. I sampled seven lakes in the summers of 2020 and 2021 to investigate the impact of historical DDTs on the present day aquatic environment. I sampled brook trout, aquatic invertebrates, zooplankton, and lake surface sediments. I found DDTs were up to ~14 times higher in brook trout muscle tissues from lakes where DDTs were applied to the watershed compared to reference lakes. DDTs in brook trout exceeded CCME guidelines by up to ~22 times. Mercury is a common contaminant of concern and delivered to lakes by atmospheric transport. Most mercury originates from anthropogenic activities, including burning fossil fuels, and mining or smelting metals rather than natural geogenic sources. I sampled brook trout from seven New Brunswick lakes in 2020, and found mercury levels comparable to similar studies in eastern North America. Mercury in brook trout exceeded CCME guidelines for methylmercury by up to ~12 times. Using DDT and mercury measures, we can further our understanding of legacy contaminants in lakes of New Brunswick, Canada.
Download or read book Mercury Bioaccumulation and Biomagnification in the Warmwater Fish Communities of Two Connecticut Lakes with an Examination of Seasonal Variations in Mercury Concentrations written by Scott M. Ward and published by . This book was released on 1997 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury in the Environment and the Implications for Brook Trout Salvelinus Fontinalis written by Jill Marie Ryan and published by . This book was released on 1991 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mercury Cycling in a Remote Boreal Drainage Basin written by Gretchen Lynne Lescord and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The consumption of freshwater fish and seafood is the main source of mercury (Hg), a widespread neurotoxic pollutant, in humans, a fact which has sparked decades of research on Hg cycling in aquatic systems. More specifically, the formation and bioaccumulation of methylmercury (MeHg) is of particular importance because it biomagnifies through aquatic food webs, resulting in relatively high levels in predatory fish despite typically low concentrations in the surrounding water. The main goal of this thesis was to assess how various watershed-level processes affect Hg bioaccumulation and biomagnification through freshwater food webs across the relatively pristine Attawapiskat Drainage Basin (ADB) in the remote Far North of Ontario. This watershed overlaps with the mineral-rich region known as the "Ring of Fire" which is expected to be heavily developed in the coming decades, likely altering the physico-chemical environments of surrounding lakes and rivers. In total, 58 lakes and river sites across the ADB were sampled for surface water quality, aquatic macroinvertebrates, and fish from 2014 to 2016. Water samples were analyzed for 39 chemical parameters including total Hg (THg; the sum of all Hg species) and MeHg concentrations ([MeHg]). Biotic samples were analyzed for [THg] and/or [MeHg], as well as carbon and nitrogen stable isotope ratios, which are indicative of an animal's food web position. In Chapter 1 of this thesis, I provide an overview of our current knowledge on Hg cycling in aquatic systems of the boreal region. In Chapter 2, I present an extensive assessment of the chemical, physical, and ecological gradients across the ADB, and an analysis of the relationships between Hg and these environmental gradients. I determined that less productive systems with higher concentrations of dissolved organic matter (DOM) had higher aqueous and biotic [Hg]. In Chapter 3, I examined how changes in the quality of DOM across the ADB relate to [Hg] in water and biota. Findings from this study suggest that more labile DOM complexes enhance MeHg bioaccumulation into food webs, while systems with more humic and aromatic DOM had higher aqueous total [Hg]. The fourth chapter critically examined the speciation of Hg in fish from across the ADB and showed substantially lower percentages of MeHg (relative to total Hg) in muscle of smaller-sized fish, particularly those which feed on littoral-based food webs and had higher lipid content in their tissue. These novel findings challenge the general assumption, used in many biomagnification studies and consumption guidelines, that all fish muscle tissue has > 95% MeHg. Finally, in Chapter 5, I discuss the implications of my research for subsistence fishers, specifically those from remote communities, where freshwater fish are important for both culture and sustenance. Here I developed some preliminary approaches to better communicating the risks and benefits of consuming fish when presenting fish tissue contaminant results in remote northern communities, including those in and around the ADB. Understanding the major influences on MeHg cycling is vital to properly monitoring the effects of industrial development (e.g., the Ring of Fire development) and climate change, which can greatly alter the physico-chemical environment of surrounding lakes and rivers. The results from my thesis indicate significant physical and chemical differences between waters in the two ecozones (i.e., the Boreal Shield and Hudson Bay Lowlands) across the ADB, presumably due to changes in bedrock geology and riparian characteristics. No other study, to my knowledge, has explored the effects of landscape position and the associated changes in physico-chemical characteristics on Hg bioaccumulation, speciation, and biomagnification on such a large scale. My findings demonstrate that monitoring programs will need to effectively track changing nutrient concentrations, DOM characteristics, and Hg bioaccumulation patterns that vary across large spatial gradients.
Download or read book The Effects of Watershed Acidification on Mercury Uptake in Brook Trout SALVELINUS FONTINALIS written by Cathryn C. Abbott and published by . This book was released on 1994 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
