Download or read book The Importance of Photochemical Processes in the Utilization of Dissolved Organic Matter by Bacteria in Two Freshwater and Two Marine Aquatic Ecosystems written by Karen Louise Bushaw and published by . This book was released on 1998 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Role of Dissolved Organic Matter in Aquatic Photochemical Oxidation Processes written by Jannis Henrik Wenk and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aquatic Ecosystems Interactivity of Dissolved Organic Matter written by Stuart Findlay and published by Academic Press. This book was released on 2003 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overviews of the source, supply and variability of DOM, surveys of the processes that mediate inputs to microbial food webs, and syntheses consolidating research findings provide a comprehensive review of what is known of DOM in freshwater. This book will be important to anyone interested in understanding the fundamental factors associated with DOM that control aquatic ecosystems."--BOOK JACKET.

Download or read book Photochemical Transformations of Dissolved Organic Matter and Its Subsequent Utilization by Marine Bacterioplankton written by Ingrid Barbara Obernosterer and published by . This book was released on 2000 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct and Indirect Photoreactions of Chromophoric Dissolved Organic Matter written by Jared Verrill Goldstone and published by . This book was released on 2002 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochemical transformations of chromophoric dissolved organic matter (CDOM) are one of the principal processes controlling its fate in coastal waters. The photochemical decomposition of CDOM leads to the formation of a variety of biologically available carbon substrates. Photomineralization of CDOM to dissolved inorganic carbon may constitute a significant flux in the global carbon cycle. Photoreactions ultimately lead to the destruction of the chromophores and hence to the loss of absorption and fluorescence (bleaching), thus acting as a sink for CDOM. Photodecomposition may proceed both via direct photochemical reactions, following absorption of photons by CDOM, or via indirect processes, involving DOM reactions with photochemically generated intermediates such as reactive oxygen species (ROS). The reactions of CDOM with two important ROS, superoxide (02- ) and hydroxyl radical (OH), have different consequences. Superoxide reactions with CDOM did not appear to degrade the CDOM. Instead, CDOM catalysed the dismutation of 02- to 02 and HOOH. This reactivity has the effect of limiting the steady-state concentration of 02- in most coastal waters. In contrast, reactions of CDOM with radiolytically produced OH formed CO2 and several low molecular weight carboxylic acids, as well as bleached both the absorption and fluorescence at slow rates. These reactions did not increase the bioavailability of this material to a microbial consortium. Both direct and indirect photochemical processes are expected to be accelerated by the presence of iron.

Download or read book Microbial and photochemical degradation of dissolved organic matter in aquatic ecosystems written by Rainer Maria Wolfgang Amon and published by . This book was released on 1995 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aquatic Organic Matter Fluorescence written by Paula G. Coble and published by Cambridge University Press. This book was released on 2014-07-14 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: A core text on principles, laboratory/field methodologies, and data interpretation for fluorescence applications in aquatic science, for advanced students and researchers.

Download or read book Photochemical Transormations of Dissolved Organic Matter and Its Subsequent Utilization by Marine Bacterioplankton written by Ingrid Barbara Obernosterer and published by . This book was released on 2000 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photochemical Reactivity of Dissolved Organic Matter in the Delaware Estuary written by Emily M White and published by . This book was released on 2007 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interaction of photochemical and microbial processes in the degradation of refractory dissolved organic matter from a coastal marine environment written by W.L. MILLER and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Characterization of Dissolved Organic Matter and Its Influence on the Photochemical Fate of Antibiotics Used in Aquaculture written by Jennifer Julia Guerard and published by . This book was released on 2009 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of source on dissolved organic matter composition were studied, and an intensive investigation was performed to characterize the photoreactivity of a fulvic acid isolated from Pony Lake on Cape Royds, Ross Island, Antarctica, a completely microbially-derived DOM end-member.

Download or read book Investigations on the Role of Dissolved Organic Matter in Determining Ecosystem Structure and Function written by Kelton Ray McKinley and published by . This book was released on 1975 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Uptake of Dissolved Organic Matter and Phosphate by Phototrophic and Heterotrophic Bacteria written by Vanessa K. Michelou and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bacterioplankton communities play a crucial role in marine biogeochemical cycles because they mediate the flux of dissolved organic matter (DOM), which is equal to about half of primary production in the ocean. These bacterial communities are also known to be very diverse and are comprised of bacteria from several different phylogenetic groups. Most biogeochemical studies of marine environments use the dichotomy of grouping microorganisms into two boxes, photoautotrophs and heterotrophs. My dissertation is about organisms and processes not described by these two boxes. An important component of my research work was the identification and quantification of organic matter uptake by marine cyanobacteria Prochlorococcus and Synechococcus. The goal of the first part of my dissertation was to identify the microbial groups responsible for light-dependent leucine incorporation and to examine the effect of light on the uptake of amino acids added at tracer levels. My hypothesis was that stimulation of bacterial production by light was due to photoheterotrophy by Prochlorococcus. My results indicated that this was in fact the case, but other groups of photoheterotrophic bacteria contributed to the light effect as well. The uptake of essential elements in reduced organic forms could provide an additional source of macronutrients to be used in protein synthesis, and help explain the success of Prochlorococcus and Synechococcus in oligorophic environments. These marine cyanobacteria are capable of accessing a wide variety of organic compounds. These results allowed me to hypothesize that these marine cyanobacteria take up dissolved organic matter for limiting elements like nitrogen and phosphorus. To determine if these cyanobacteria were also capable of assimilating non-limiting organic compounds without nitrogen or phosphorus, uptake rates of amino acids and glucose by Prochlorococcus, Synechococcus and heterotrophic bacteria were determined in the Sargasso Sea in May and September of 2008 using flow cytometry. This study revealed that glucose uptake by Synechococcus was significantly higher than uptake by both Prochlorococcus and heterotrophic bacteria in all samples, while uptake by Prochlorococcus and heterotrophic bacteria was similar. These results suggested that coccoid cyanobacteria are competitive at assimilating dissolved organic compounds without nitrogen or phosphorus, though these microbes accounted for a small fraction of total uptake. Phosphorus potentially limits the growth and productivity of microbial communities in many oligotrophic oceans. Both dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) could be an important resource in these regimes. Assimilation rates of inorganic and organic phosphorus by marine cyanobacteria and heterotrophic bacteria in the oligotrophic ocean are not well quantified. For the last chapter of my dissertation, I used radioisotope tracers of orthophosphate and ATP combined with flow cytometry sorting to quantify assimilation by heterotrophic bacteria, Prochlorococcus and Synechococcus during the fall of 2007 and 2008 and the spring of 2009 in the western Sargasso Sea. Phosphate and ATP uptake rates were 50-fold and 80-fold higher for Synechococcus compared to the other two groups. However, there was no significant difference between ATP and phosphate uptake by Prochlorococcus and heterotrophic bacteria. Total uptake of phosphate and ATP was dominated by heterotrophic bacteria, while uptake by Prochlorococcus and Synechococcus was a smaller fraction of the total. This coincided with the lower abundance of these cyanobacteria (25% and 2.5% of total prokaryotes respectively) compared to heterotrophic bacteria during my study. Phosphate and ATP turnover was surprisingly similar for the three groups analyzed, suggesting P uptake by marine cyanobacteria is not that different from uptake by heterotrophic bacteria. Collectively, these data suggest that inorganic and organic P play an important role in the ecological success of marine cyanobacteria in the Sargasso Sea. The current study added to the growing information regarding the role of specific bacterial groups, such as cyanobacteria, in DOM assimilation. In particular, this study was the first to unfold the contribution of photoheterotrophic microbes to leucine assimilation in the North Atlantic Ocean. My results not only provided new evidence of carbon uptake by phototrophic picoplankton, they lay the foundation for a number of new interesting questions regarding these extremely successful microorganisms.

Download or read book Photochemical transformations of surface and deep marine dissolved organic matter written by R. BENNER and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Treatise on Estuarine and Coastal Science written by and published by Academic Press. This book was released on 2012-03-06 with total page 4604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of estuaries and coasts has seen enormous growth in recent years, since changes in these areas have a large effect on the food chain, as well as on the physics and chemistry of the ocean. As the coasts and river banks around the world become more densely populated, the pressure on these ecosystems intensifies, putting a new focus on environmental, socio-economic and policy issues. Written by a team of international expert scientists, under the guidance of Chief Editors Eric Wolanski and Donald McClusky, the Treatise on Estuarine and Coastal Science, Ten Volume Set examines topics in depth, and aims to provide a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Most up-to-date reference for system-based coastal and estuarine science and management, from the inland watershed to the ocean shelf Chief editors have assembled a world-class team of volume editors and contributing authors Approach focuses on the physical, biological, chemistry, ecosystem, human, ecological and economics processes, to show how to best use multidisciplinary science to ensure earth's sustainability Provides a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Features up-to-date chapters covering a full range of topics

Download or read book The Role of Dissolved Organic Matter in Structuring Microbial Community Composition written by Rachel Elizabeth Sipler and published by . This book was released on 2009 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) is an important source of nutrients in aquatic systems contributing to the growth of phytoplankton and bacteria. The overall response appears to be driven by the phytoplankton and bacteria species present as well as the composition of DOM provided. This dissertation explores the bioavailability of allochthonous and autochthonous DOM sources to, and its affect on, the growth of marine phytoplankton and bacterial community abundance and composition. This research utilizes advanced chemical (electrospray ionization mass spectrometry (ESI-MS)) and molecular (terminal restriction fragment length polymorphism (TRFLP)) techniques to characterize the DOM and microbial community. To investigate the role of allochthonous DOM in phytoplankton growth, DOM from two different riverine sources from watersheds with different land use practices, was supplied to a natural cyanobacteria population. The bioavailability of autochthonous DOM was investigated by supplying DOM produced by a single culture of cyanobacteria to a natural dinoflagellate bloom community. The potential negative effect of an individual autochthonous DOM compound was investigated through the addition of marine toxin, brevetoxin, to three different natural bacterial communities. This dissertation resulted in the first ESI-MS characterization spectra of the DOM associated with three different natural phytoplankton blooms, a culture of cyanobacteria, and two different South Florida rivers. It was also the first study to identify previously uncharacterized allochthonous and autochthonous DOM masses bioavailable to natural marine phytoplankton communities. Bulk level analyses within these experiments quantified lower limits for the bioavailability of allochthonous and autochthonous DOM sources and the relative community response to each of these sources. This dissertation also represents the first molecular evaluation of the bacteria associated with a bloom and the first investigation of the allelopathic properties of brevetoxin. It has discussed and applied the use of ESI-MS to investigate the bioavailability of complex DOM, identified and quantified potential nutrient sources and linked marine toxin production to changes in bacterial community composition.