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Estimation Of The Contribution Of Biological Nitrogen Fixation To The Nitrogen Budget In A Freshwater Lake
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Book Synopsis Estimation of the Contribution of Biological Nitrogen Fixation to the Nitrogen Budget in a Freshwater Lake by : Riley Ann Baxter
Download or read book Estimation of the Contribution of Biological Nitrogen Fixation to the Nitrogen Budget in a Freshwater Lake written by Riley Ann Baxter and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen (N) is an essential nutrient for all organisms. A lack of N can limit primary production, but an excess of N can cause harmful algal blooms and consequences to freshwater quality. Freshwater environments contain N fixing organisms whose contribution to the N cycle through organic inputs remains unclear because their N fixation rates and controls are understudied. Without knowing how much N comes into the freshwater ecosystem from fixation, it is difficult to fully understand food webs, N cycling and difficult to manage nutrient pollution. This research addressed the question of how much N fixation contributes to the N budget of a freshwater lake in northeast Washington State. We measured N fixation rates in cyanobacteria and sediment bacteria using a 15N2 tracer method during an in-lab incubation. No correlation was found between N fixation rates and the environment's temperature, dissolved oxygen (mg/L), percent dissolved oxygen, pH, conductivity, nor total N and total phosphorus (P) water concentrations. However, a slight positive relationship between N:P rates in the water's surface and N fixation was observed. Although the rates we measured were low, we still found that the contribution of N from lake diazotrophs was similar to that of N inputs coming from allochthonous sources during autumn, suggesting that N fixation is seasonally important.
Book Synopsis Fluxes and Controls of the Contribution of Nitrogen-fixation to the Nitrogen Budget in Streams by : Lisa A. Kunza
Download or read book Fluxes and Controls of the Contribution of Nitrogen-fixation to the Nitrogen Budget in Streams written by Lisa A. Kunza and published by . This book was released on 2012 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: N2 -fixing bacteria convert N2 gas from the atmosphere into biologically available forms via the nitrogenase enzyme. N2-fixation is a natural flux of N to an ecosystem. The flux of N into some terrestrial and aquatic ecosystems via N2-fixation can be substantial and account for up to 97% of new N inputs. Yet, little is known about the importance of N2-fixation in streams. My objectives were to examine the controls on N2-fixation, evaluate current methods for measuring N2-fixation, and estimate the contribution of N2-fixation to N cycling in Wyoming streams. I examined how nutrients may partially control N2-fixation using 4-hour and 6-week nutrient incubations. During 4-hour incubations, the N2-fixation flux of intact stream biofilm was resistant to ammonium (NH4+ ), nitrate (NO3−), and phosphate (PO43−) additions at varying concentrations and the N2-fixation fluxes remained unaltered. On the other hand, the 6-week additions of NO3− and PO43−- altered chlorophyll a, algal assemblage structure, and N2-fixation fluxes. N2-fixation was inhibited by NO3− and stimulated by PO43− , and the inhibitory effect of NO3− was stronger than the stimulating effect of PO43−. When measuring N2-fixation via the acetylene reduction method a conversion ratio of ethylene produced to N2-fixed (C2 H4 :N2) must be assumed or calibrated. The C2 H4 :N2 ratio for benthic biofilms in streams remained unclear. Using both the acetylene reduction method and 15 N2 uptake methods, I examined the C2 H4 :N2 ratio, estimated controls on the ratio, and measured the immediate release of N2-fixed. Our average estimate of the C2 H4 :N2 ratio was 5.4 (n=85). Immediate release of N2-fixed as dissolved N was less than 1% of N2-fixation. Ethylene production increased 10 times faster than N2-fixation as stream temperature increased. Thus, stream temperature drove the variability observed in the ratios of ethylene produced to N2-fixed. To estimate the contribution of N2-fixation to stream N cycling processes, I compared N2-fixation with dissolved inorganic N (DIN) uptake fluxes. N2-fixation exceeded NO3− uptake in 2 of 9 streams and NH4+ uptake in one stream. Throughout the summer season in one stream, Ditch Creek, N2 -fixation exceeded DIN uptake up to 8-fold. Ditch Creek N2 -fixation fluxes surpassed denitrification rates for many streams. N2-fixation can be a dominant flux in stream N cycling, but as DIN concentrations increase in streams this flux may diminish.
Book Synopsis Biological Nitrogen Fixation in Lake Mendota by : Marguerite Lois Sherman Torrey
Download or read book Biological Nitrogen Fixation in Lake Mendota written by Marguerite Lois Sherman Torrey and published by . This book was released on 1972 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rates, Importance, and Controls of Nitrogen Fixation in Oligotrophic Arctic Lakes, Toolik, Alaska by : Gretchen Maria Gettel
Download or read book Rates, Importance, and Controls of Nitrogen Fixation in Oligotrophic Arctic Lakes, Toolik, Alaska written by Gretchen Maria Gettel and published by . This book was released on 2006 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological nitrogen (N) fixation of atmospheric N2 by free-living cyanobacteria in aquatic environments is common, and in many ecosystems, it can account for a significant portion of the biologically available N inputs. Although N fixation can compensate for N limitation, N limitation is maintained over relatively long time scales in many oligotrophic lake ecosystems. This dissertation examines the importance of benthic and pelagic N fixation in the N economies of oligotrophic lakes in arctic Alaska (Chapter 1) and examines nutrient, light, and grazer controls on benthic N fixation (Chapters 2 and 3). Both benthic and pelagic N fixation are prevalent in many lakes across the Alaskan arctic landscape, ranging from 0.12 - 1.5 mg N m-2 day-1 and 0 - 2.56 mg N m-2 day-1 respectively. Pelagic N fixation is much higher than has been reported elsewhere for oligotrophic lakes, and is more important than previously thought, comprising ~ 75% of N inputs to one lake. Benthic N fixation is lower than has been reported for other oligotrophic systems, and is roughly equivalent to N inputs from atmospheric deposition on an areal basis (~25 mg N m-2 year-1). On the landscape scale, N fixation in lakes roughly equal that in terrestrial ecosystems in this Arctic region. Benthic N fixation generally appears to have a saturating response to light availability within individual lakes, but light does not explain variation in benthic N fixation across lakes or years. Whole-lake fertilization and laboratory experiments indicate that P input stimulates benthic N fixation while N input suppresses N fixation when N is added either alone or in conjunction with P in Redfield proportion. Snails at ambient density cause a small decline in benthic N fixation (0.85 - 1.8% reduction over the summer). These patterns are corroborated in the landscape: lakes on younger surfaces have higher P, more snails, and higher rates of N-fixation than lakes on older surfaces. (Abstract).
Book Synopsis Nitrogen Fixation: Sediment Contribution to Nitrogen Budgets of Lake Mendota and Lake Wingra by : A. N. Macgregor
Download or read book Nitrogen Fixation: Sediment Contribution to Nitrogen Budgets of Lake Mendota and Lake Wingra written by A. N. Macgregor and published by . This book was released on 1972 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Estimating Nutrient Loadings of Lakes from Non-point Sources by : Paul D. Uttormark
Download or read book Estimating Nutrient Loadings of Lakes from Non-point Sources written by Paul D. Uttormark and published by . This book was released on 1974 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Nitrogen Cycle at Regional to Global Scales by : Elizabeth W. Boyer
Download or read book The Nitrogen Cycle at Regional to Global Scales written by Elizabeth W. Boyer and published by Springer Science & Business Media. This book was released on 2002-07-31 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boyer (State U. of New York at Syracuse) and Howarth (Marine Biological Lab, Woods Hole, Massachusetts) present the final report of the International Scientific Committee on the Problems of the Environment project that was devoted to the study of human impact on global and regional nitrogen recycling. The report consists of 15 papers that look at control processes of nitrogen transport and transformations and their importance in the global nitrogen budget; quantify inputs of nitrogen from natural and anthropogenic sources in the northeastern USA; and estimate regional and landscape- scale nitrogen budgets. Annotation (c)2003 Book News, Inc., Portland, OR (booknews.com).
Book Synopsis Marine Nitrogen Fixation by : Jonathan P. Zehr
Download or read book Marine Nitrogen Fixation written by Jonathan P. Zehr and published by Springer Nature. This book was released on 2021-04-02 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to serve as a centralized reference document for students and researchers interested in aspects of marine nitrogen fixation. Although nitrogen is a critical element in both terrestrial and aquatic productivity, and nitrogen fixation is a key process that balances losses due to denitrification in both environments, most resources on the subject focuses on the biochemistry and microbiology of such processes and the organisms involved in the terrestrial environment on symbiosis in terrestrial systems, or on largely ecological aspects in the marine environment. This book is intended to provide an overview of N2 fixation research for marine researchers, while providing a reference on marine research for researchers in other fields, including terrestrial N2 fixation. This book bridges this knowledge gap for both specialists and non-experts, and provides an in-depth overview of the important aspects of nitrogen fixation as it relates to the marine environment. This resource will be useful for researchers in the specialized field, but also useful for scientists in other disciplines who are interested in the topic. It would provide a possible text for upper division classes or graduate seminars.
Book Synopsis Nitrogen and Phosphorus in Water by : United States. Division of Water Supply and Pollution Control
Download or read book Nitrogen and Phosphorus in Water written by United States. Division of Water Supply and Pollution Control and published by . This book was released on 1965 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Selected Water Resources Abstracts by :
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1990 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Estimating Nutrient Loadings of Lakes from Non-point Sources by : United States. Environmental Protection Agency
Download or read book Estimating Nutrient Loadings of Lakes from Non-point Sources written by United States. Environmental Protection Agency and published by . This book was released on 1974 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nitrogen in the Marine Environment by : Douglas G. Capone
Download or read book Nitrogen in the Marine Environment written by Douglas G. Capone and published by Elsevier. This book was released on 2008-08-15 with total page 1759 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the first edition of Nitrogen in the Environment published in 1983, it has been recognized as the standard in the field. In the time since the book first appeared, there has been tremendous growth in the field with unprecedented discoveries over the past decade that have fundamentally changed the view of the marine nitrogen cycle. As a result, this Second Edition contains twice the amount of information as contained in the first edition. This updated edition is now available online, offering searchability and instant, multi-user access to this important information. *The classic text, fully updated to reflect the rapid pace of discovery*Provides researchers and students in oceanography, chemistry, and marine ecology an understanding of the marine nitrogen cycle*Available online with easy access and search - the information you need, when you need it
Book Synopsis Nutrients in Natural Waters by : Herbert Ellis Allen
Download or read book Nutrients in Natural Waters written by Herbert Ellis Allen and published by Wiley-Interscience. This book was released on 1972 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest thinking and research on nutrients have been brought together by experts in the chemical and biological sciences and in engineering. The authors represent educational institutions, government, and industry. The book features a broad discussion of the topic. In addition to chapters on the three principal nutrients (nitrogen, phosphorus, and carbon), chapters on nutrient geochemistry and nutrient regeneration in hypolimnetic waters are included. Both chemical and bioassay analyses of nutrients are discussed by experts in their respective fields. Computer models of nutrient biochemical processes are described with the use of many illustrations, so that even those unfamiliar with computer techniques can appreciate their utility.
Book Synopsis Methods for Evaluation Biological Nitrogen Fixation by : F.J. Bergersen
Download or read book Methods for Evaluation Biological Nitrogen Fixation written by F.J. Bergersen and published by . This book was released on 1996 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Biological Nitrogen Fixation in the Great Lakes by : T. H. Mague
Download or read book Biological Nitrogen Fixation in the Great Lakes written by T. H. Mague and published by . This book was released on 1973 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of Nitrogen-fixation in Natural Fresh Waters by : John James Goering
Download or read book Studies of Nitrogen-fixation in Natural Fresh Waters written by John James Goering and published by . This book was released on 1962 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nitrogen Cycling in the North Atlantic Ocean and its Watersheds by : Robert W. Howarth
Download or read book Nitrogen Cycling in the North Atlantic Ocean and its Watersheds written by Robert W. Howarth and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Human activity has dramatically altered the global nitrogen cycle in recent decades. These changes are not evenly distributed around the world; rather, they are greatest in regions of significant industrial and agricultural activity, as the synthesis and use of inorganic fertilizers, cultivation of legumes, burning of fossil fuels, and the simple act of concentrating humans and animals in dense populations all lead to the release of excess, reactive forms of nitrogen into the environment. In part because reactive nitrogen is frequently a limiting nutrient in many terrestrial and aquatic systems, an excess can lead to a variety of adverse effects on both environmental and human health. The North Atlantic Ocean and its contributing watersheds constitute a region which has seen perhaps the greatest increase in anthropogenically-derived nitrogen. In May of 1994, the International Scope Nitrogen Project, with funding from the Andrew Mellon Foundation, the United Nations Environment Program, and the World Meteorological Organization, sponsored a workshop held on Block Island, RI, USA, entitled `Nitrogen Dynamics of the North Atlantic Basin'. More than 50 scientists from 12 different countries convened with a unique set of goals: an integrated and comprehensive estimate of the current nitrogen cycle of the ocean, coastal systems, and contributing watersheds of the North Atlantic region; an analysis of human-induced changes to those cycles; and an assessment of the current and future effects of human-induced changes to nitrogen cycling throughout the globe.
