Download or read book Influence of Dissolved Organic Carbon DOC on Fish Production in North temperate Lakes written by Pierre-Olivier Benoit and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Terrestrial inputs of dissolved organic carbon (DOC) can have strong effects on the physical, chemical and biological characteristics of lake ecosystems which can in turn be reflected by changes in production of aquatic organisms. The first chapter of this thesis described the interconnections between aquatic and terrestrial ecosystems and reviewed the different mechanisms through which variable inputs of terrestrial organic carbon could influence fish community dynamics in freshwater environments, and how these effects could be related to changes in fish production. The second chapter evaluated if growth and relative abundance/biomass of three common North American fish species: yellow perch (Perca flavescens), walleye (Sander vitreus), and lake trout (Salvelinus namaycush) are negatively, positively or not correlated with variable DOC concentration and how this relation varies between species. In general, our results provide only limited support of a possible relation between fish production and DOC concentration. Walleye growth rates declined by 50 % across a DOC range from 4.6 to 16.0 mg·l-1 but no relation were observed for yellow perch across a DOC range from 4.1 to 15.7 mg·l-1. Variable reductions in walleye growth and yellow perch relative abundance/biomass were observed along with increases of DOC concentration. Increases in lake trout production were not related to DOC (ranging from 2.6 to 8.8 mg·l -1), but strongly related to higher total phosphorus (TP) concentration and to some extent, lower latitude. Hence, the importance of the DOC-growth relation was not consistent between each fish species included in our analysis, suggesting that a species-specific approach should be prioritized over a more general approach when evaluating the possible effect of changes in DOC concentration on freshwater fish production." --

Download or read book Impacts of Dissolved Organic Carbon on Productivity of Fish and Benthic Macroinvertebrates in North Temperate Lakes written by Nicola Craig and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Over the past several decades, increases in concentrations of dissolved organic carbon (DOC) have been observed in many north temperate aquatic ecosystems, a phenomenon known as aquatic 'browning', however the ecological consequences of this increase are not well understood. DOC from terrestrial sources stains lake water a dark brown color, and can have strong effects on the physical and biological structure of lake ecosystems. This occurs through its associated light and heat attenuating properties, which reduce thermocline depths, and thus the area of light, warm, and well-oxygenated habitat in DOC-rich lakes. Recent spatial surveys, where consumers were sampled from various lakes spanning a DOC gradient, have shown that fish productivity decreases along a gradient of increasing DOC, however the mechanisms behind this have not been fully explored. This thesis demonstrates potential mechanisms for this loss in productivity by determining how DOC affects zoobenthos, a primary prey item for many fish, as well as how DOC affects fish feeding efficiency and life history strategies.I begin by demonstrating, through the use of a spatial lake survey, that zoobenthos production declines over an increasing DOC gradient, and that this decline is due to limitations in oxygen-rich habitat availability, rather than the previously assumed mechanism of primary resource limitation. As many fish are visual predators, and high levels of DOC may reduce visibility, I then examined how DOC may affect fish feeding efficiency using mesocosm experiments and another gradient-based diet survey. I showed that bluegill (Lepomis macrochirus) feeding efficiency is not affected by DOC concentration, suggesting that these benthivores use cues other than vision to detect prey in darker, DOC-rich lakes. The reduction of fish productivity with increasing DOC is likely manifested through shifts in life history characteristics that are important to understand if we are to better manage fisheries with increasing browning. Again using bluegill as a model organism, I show that in low-DOC lakes, fish are able to attain enough energetic resources to reproduce as well as continue to grow after maturity. However, in high-DOC lakes, growth slows after maturity is reached, and so overall reproductive output and maximum size is reduced in these populations.Currently, the majority of studies focusing on the effects of DOC on consumer productivity are based on spatial gradient surveys, models, and mesocosm experiments. However, browning is a temporal process, and these studies may not accurately reflect how consumers may react to increases of DOC over time. In my final chapter, I describe a whole-ecosystem experiment were we divided a lake in two and increased DOC in one basin, comparing the effects on zoobenthos biomass and productivity to a reference basin, as well as the spatial survey from the first chapter. I show that, contrary to the results of the spatial survey, zoobenthos productivity actually increased with increasing DOC concentrations in this temporal experiment. This result suggests that there may be transitional effects of DOC increases on zoobenthos communities, and that the relationship between DOC and ecosystem productivity may be non-linear. This thesis highlights the need for multiple approaches in order to untangle the complex effects of DOC in lake ecosystems. The observations within will help us better predict how consumers in lake ecosystems may react in the face of future increases in DOC, and how to manage them accordingly. " --

Download or read book Dissolved Organic Carbon in Lakes written by Jeffrey Neil Houser and published by . This book was released on 2001 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating the Effects of Dissolved Organic Carbon DOC on Zoobenthos and Fish Productivity Through a Whole lake Experiment written by Shuntaro Koizumi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Lakes across the northern hemisphere have been increasing in dissolved organic carbon (DOC) concentrations over the last few decades. This increase in DOC has a wide-range of effects on the overall productivity of lakes. In this thesis, we used a whole-lake experiment to test the effects of increased DOC on the productivity of lake food-webs, specifically on the fish and macroinvertebrate community. The first chapter of this thesis focuses on looking at the effects of an increase in DOC on the productivity of a Largemouth Bass population. Using a before-after control-impact (BACI) design, we assessed the effects of a DOC increase on the bass productivity over a five-year span. We found that the DOC-induced shading reduced the preferred habitat space of the bass, resulting in an increase in their density within the epilimnion. We found changes in their diet composition and a decreased probability of an empty stomach. Overall, there was no net change in their productivity, but we found evidence for possible future effects through changes in their recruitment success. The second chapter of this thesis focuses on observing the effects of a DOC increase on the productivity of Chironomus midge larvae, a dominant species in the benthic macroinvertebrate community within our experimental lake. We used both a literature-derived bioenergetics model and field observations to study the DOC-related mechanisms that drive changes in their productivity. We found that the DOC increase lead to overall biomass increase, and a consequent increase in their productivity. However, individual fitness, in terms of growth and maturation duration, was reduced with an increase in DOC. Both chapters of this thesis demonstrate that a stronger understanding of the mechanistic responses in the food-web are required to fully understand the effects of DOC on lake systems. Without a more holistic understanding of the effects of an increase in DOC, the effective management of lakes to this global phenomenon will be difficult. " --

Download or read book Dissolved Organic Matter in Lacustrine Ecosystems written by K. Salonen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concentrations of dissolved organic matter (DOM) in lakes are often an order of magnitude greater than concentrations of particulate organic matter; nevertheless, the biogeochemical analysis of DOM is described in only a few textbooks on limnology (most thoroughly by Wetzel). The orgins of dissolved organic substances are largely photosynthetic; DOM is either autochthonously synthesized by littoral and pelagic flora through secretions and autolysis of cellular contents, or allochthonously generated in terrestrial systems of the drainage basin, composing largely of humic substances refractory to rapid microbial degradation. The role of DOM in lacustrine ecosystems, as energy source and system regulator, however, is still poorly known. The aim of this book is: (1) to present state-of-the-art reviews of the role of dissolved autochthonous and allochthonous organic matter in pelagial and littoral zones; and (2) to focus attention on poorly understood but critical topics and hence to provide direction for future research activity.

Download or read book Riparian Management in Forests of the Continental Eastern United States written by Ellen S. Verry and published by CRC Press. This book was released on 1999-12-06 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: The timing could not be better for addressing riparian area management and the resulting impacts of surface water. The Forest Service leadership team has identified water and watershed management as the issue of the upcoming decade. These factors and more have moved riparian forests to the forefront of environmental management. Riparian Management in Forests of the Continental Eastern United States gives you the tools you need to take on this task. Each day, thousands of natural resource professionals face the problems involved in managing riparian forests. The challenge: fragmented ownership, fragmented ecosystems, and diverse interest groups. The solution requires a multidisciplinary approach, drawing on a complex mix of government agencies, private interests, and local communities as exemplified in the following initiatives: Chesapeake Bay Program "Save the Bay" Inland West Water Strategy New York City Watershed Project The Pacific Habitat Strategy The Anadromous Fish Habitat Riparian Management in Forests of the Continental Eastern United States summarizes the state-of-the-art in the management of forested riparian areas. It serves as a desktop reference for natural resource administrators, educators, and on-the-ground managers from industry, consulting firms, and municipal, state, and federal agencies who routinely face the complex problems of protecting riparian areas. Features

Download or read book Microbial Utilization and Transformation of Dissolved Organic Matter in Aquatic Environments from Streams to the Deep Ocean written by Johanna Sjöstedt and published by Frontiers Media SA. This book was released on 2021-07-28 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Does Dissolved Organic Matter Impact Primary Production A Study on the Effects of Terrestrially Derived Dissolved Organic Matter on Primary Production in Nutrient poor Boreal Lakes written by Bryanna Sherbo and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few decades, spatial and temporal variation in concentrations of allochthonous dissolved organic carbon (DOC) has been increasing in surface waters of boreal lakes around the world with climate change. Terrestrial landscapes export large amounts of organic matter into lakes, primarily as DOC. It is understood that DOC impacts primary production through its combined effects on light and nutrient availability. However, there remains uncertainty as to the mechanisms that cause DOC to have positive or negative effects on algal productivity. In a survey of 6-7 lakes spanning a DOC gradient (3.5-9.4 mg L-1) at International Institute of Sustainable Development-Experimental Lakes Area (IISD-ELA) in northwestern Ontario, we determined the effects of DOC on whole-lake metabolism (gross primary production (GPP), respiration, and net ecosystem production (NEP)) and depth integrated net primary production (NPP). Using in situ diel free-water oxygen method and in vitro partial pressure of CO2 incubations, we found that primary production was significantly impacted by DOC. In general, the effects of DOC on algal productivity was negative, although there was some evidence for the stimulation of whole ecosystem production by nutrients at low DOC concentrations. Epilimnetic chlorophyll, GPP, and community respiration increased significantly with DOC, and total depth integrated and sub-epilimnetic NPP decreased significantly with DOC. Lakes with the highest proportion of sub-epilimnetic production had well developed deep chlorophyll maxima (DCM). DCM were negatively correlated with DOC and are viewed as ecological hotspots for higher trophic levels. DCM and sub-epilimnetic productivity were eliminated in lakes with DOC values > 7.1 mg L-1. These results substantiate the influence of allochthonous DOC on aquatic food webs and highlight the combined effects of DOC on light and nutrient availability. The association of DOC with epilimnetic nutrients caused an increase in epilimnetic GPP (chapter 2) and decreasing light availability caused a decrease in total and sub-epilimnetic NPP (chapter 3). These contrasting effects of DOC on primary production provide further insight into the balance between nutrients and light with increasing concentrations of DOC.

Download or read book Dissolved Organic Carbon Dynamics in Lakes and Streams in Northern Wisconsin written by Vanessa Czeszynski and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic carbon (DOC) is naturally occurring; however, various aspects of global climate change are increasing anthropogenic DOC in freshwater systems. Here we focus on lakes and streams in the Northern Lakes and Forests region of Wisconsin. This study aimed to 1) determine DOC concentration and composition in these systems, 2) compare DOC dynamics between system types and each month sampled, and 3) determine if relationships exist between DOC and nutrient quantities and microbial community production. This study found that DOC ranged from 2.62 - 61.35 mg/L, with no differences in DOC concentrations between the system types or months sampled. However, DOC composition differed greatly between system type and months, with lakes having more autochthonous carbon and streams having more allochthonous carbon (p

Download or read book The Effects of Dissolved Organic Carbon on Pathways of Energy Flow Resource Availability and Consumer Biomass in Nutrient poor Boreal Lakes written by Joseph Tonin and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few decades, terrestrially derived dissolved organic carbon (DOC) has been recognized as a fundamental driver of food web productivity in nutrient poor lakes. The mechanisms that underlie these effects remain poorly understood, particularly for higher trophic levels including zooplankton, benthic invertebrates, and fish. In a survey of eight lakes in northwestern Ontario, I determined consumer biomass and used stable isotopes of carbon, nitrogen, and hydrogen to investigate relationships between DOC and pathways of energy flow, resource and habitat availability, and consumer biomass. Using Bayesian stable isotope mixing models, I found that hypolimnetic phytoplankton were an important resource for zooplankton in low-DOC lakes. With increased DOC concentrations, light attenuation increased and chlorophyll a concentrations below the thermocline were reduced relative to epilimnetic concentrations. At higher DOC concentrations, zooplankton acquired proportionately more energy from low quality terrestrial sources. Zooplankton biomass also declined with increasing utilization of terrestrial sources (allochthony), suggesting that terrestrial organic matter suppresses zooplankton productivity through simultaneous limitations on habitat and resource availability and quality. Based on biomass, the dominant fish species across my study lakes was White Sucker (Catostomus commersonnii). Bayesian mixing models indicated that allochthony by White Suckers increased with DOC and that greater allochthony was related to lower White Sucker biomass measured as catch-per-unit-effort (bCPUE). Both White Sucker bCPUE and chironomid biomass were positively related to mean light irradiance, with the highest biomasses of fish and chironomids occurring in lakes with a higher proportion of their volume in the photic zone. White Sucker bCPUE was strongly and positively correlated with chironomid biomass, suggesting that DOC-mediated resource limitation may influence fish productivity via reduced prey availability.

Download or read book Metabolism in the Surface Waters of North Temperate Lakes written by Paul Conrad Hanson and published by . This book was released on 2003 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 2009-10 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Detecting trends of annual values of atmospheric pollutants by the Mann Kendall test and Sen s slope estimates the Excel template application MAKESENS written by Timo Salmi and published by . This book was released on 2002 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Environment Research and Application 2013 Edition written by and published by ScholarlyEditions. This book was released on 2013-06-21 with total page 1043 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Environment Research and Application: 2013 Edition is a ScholarlyEditions™ book that delivers timely, authoritative, and comprehensive information about Climate Change and Global Warming. The editors have built Advances in Environment Research and Application: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Climate Change and Global Warming in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Environment Research and Application: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Download or read book Lipids in Aquatic Ecosystems written by Michael T. Arts and published by Springer Science & Business Media. This book was released on 2009-06-12 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evidence now suggests that the roles of essential fatty acids as growth promoters and as indices of health and nutrition are fundamentally similar in freshwater and marine ecosystems. Lipids in Aquatic Ecosystems integrates this divergent literature into a coordinated, digestible form. Chapters are organized so as to discuss and synthesize the flow of lipids from lower to higher trophic levels, up to and including humans. Linkages between the production, distribution and pathways of these essential compounds within the various levels of the aquatic food webs, and their ultimate uptake by humans and other terrestrial organisms, are highlighted throughout the book. This book will be of interest to researchers and resource managers working with aquatic ecosystems.

Download or read book Sources and Cycling of Dissolved Organic Carbon Across a Landscape of Arctic Delta Lakes written by Suzanne E. Tank and published by . This book was released on 2009 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic carbon (DOC) is a key regulator of aquatic ecosystems, and the primary substrate for aquatic bacteria. However, variations in function between different DOC sources are rarely studied. Arctic Mackenzie Delta lakes exhibit striking differences in DOC composition, with DOC sources ranging from C produced as a byproduct of aquatic plant (macrophyte) photosynthesis, to C derived from permafrost melting (thermokarst), and C delivered to lakes via river-water. This study assessed how variations in DOC source regulate the composition of the within-lake pool, drive bacterial metabolism and the contribution of bacterial biomass to higher trophic levels, and affect CO2 flux from Delta lakes. DOC-specific tracers showed macrophyte-derived DOC to comprise less than 15% of the DOC pool in macrophyte-rich lakes, despite macrophyte C levels 7-12-fold greater than total DOC. However, bacterial 13C indicated that bacteria preferentially incorporate DOC generated by macrophytes, while surveys and incubation experiments showed that bacterial metabolism is rapid on macrophytic DOC, with high rates of bacterial biomass production relative to respiratory loss as CO2. Accordingly, 13C, 15N, and fatty acid biomarkers demonstrated that zooplankton from macrophyte-rich lakes receive a greater proportion of their biomass from bacterial organic matter than zooplankton from other lake types. At the same time, however, experiments indicated that the high pH resulting from rapid photosynthesis in macrophyte-rich lakes can decrease the rate of bacterial metabolism over the short-term, and increase CO2 respiration at the expense of bacterial biomass production. In contrast, DOC-specific tracers indicated that thermokarst-derived DOC accumulates in lakes. Incubation experiments and In situ surveys revealed thermokarst DOC to be a relatively poor bacterial substrate, which resulted in proportionately more CO2 respiration, relative to bacterial biomass production, than observed for other Delta DOC sources. Moreover, multi-year surveys demonstrated that thermokarst lakes exhibit high levels of CO2 emission, despite clear undersaturation in other lakes, presumably because permafrost-derived DOC was largely respired by bacteria. Understanding the divergent roles played by the contrasting sources of DOC to Delta lakes both adds insight to the functioning of other lake regions, globally, and helps clarify the effect of climate-induced changes in DOC on northern lakes.

Download or read book Aquatic Humic Substances written by Dag Hessen and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humic substances occur in all kinds of aquatic systems, but are particularly important in northern, coniferous areas. They strongly modify the aquatic ecosystems and also constitute a major problem in the drinking water supply. This volume covers all aspects of aquatic humic substances, from their origin and chemical properties, their effects on light and nutrient regimes and biogeochemical cycling, to their role regarding organisms, productivity and food web organization from bacteria to fish. Special emphasis is paid to carbon cycling and food web organization in humic lakes, but aspects of marine carbon cycling related to humus are treated as well.