Download or read book Effects of Inter tributary Dissolved Organic Carbon Variability on Heterotrophic Microbial Communities in Upper Winyah Bay SC written by Emma K. Wear and published by . This book was released on 2009 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatio temporal Variation and Dissolved Organic Carbon Processing of Streambed Microbial Community written by Philips Olugbemiga Akinwole and published by . This book was released on 2013 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sedimentary microbial communities play a critical ecological role in lotic ecosystems and are responsible for numerous biogeochemical transformations, including dissolved organic matter (DOM) uptake, degradation, and mineralization. The goals of this study were to elucidate the benthic microbes responsible for utilization of humic DOM in streams and to assess overall variability in microbial biomass and community structure over time and across multiple spatial scales in stream networks, as DOM quality and quantity will likely change with stream order. In Chapter 2, multiple spatial patterns of microbial biomass and community structure were examined in stream sediments from two watersheds; the Neversink River watershed (NY; 1st, 3rd and 5th order streams sampled) and the White Clay Creek watershed (PA; 1st through 3rd order streams sampled). Microbial biomass and community structure were estimated by phospholipid phosphate and phospholipid fatty acids (PLFA) analyses. Multivariate analysis showed that sedimentary C:N ratios, percent carbon, sediment surface area and percent water content explained 68% of the variations in total microbial biomass. Overall, the magnitude of within stream variation in microbial biomass was small compared to the variability noted among streams and between watersheds. Principal component analysis (PCA) of PLFA profiles showed that microbial community structure displayed a distinct watershed-level biogeography, as well as variation along a stream order gradient. Chapter 3 demonstrated that benthic microbial biomass was seasonally dynamic and significantly correlated to a combination of high and low flood pulse counts, variability in daily flow and DOC concentration in the White Clay Creek. Additionally, the seasonal pattern of variation observed in microbial community structure was as a result of shift between the ratios of prokaryotic to eukaryotic component of the community. This shift was significantly correlated with seasonal changes in median daily flow, high and low flood pulse counts, DOC concentrations and water temperature. Compound-specific 13C analysis of PLFA showed that both bacterial and microeukaryotic stable carbon isotope ratios were heaviest in the spring and lightest in autumn or winter. Bacterial lipids were isotopically depleted on average by 2 - 5 / relative to δ13C of total organic carbon suggesting bacterial consumption of allochthonous organic matter, and enriched relative to δ13C algae-derived carbon source. In Chapter 4, heterotrophic microbes that metabolize humic DOM in a third-order stream were identified through trace-additions of 13C-labeled tree tissue leachate (13C-DOC) into stream sediment mesocosms. Microbial community structure was assessed using PLFA biomarkers, and metabolically active members were identified through 13C-PLFA analysis (PLFA-SIP). Comparison by PCA of the microbial communities in stream sediments and stream sediments incubated in both the presence and absence of 13C-DOC showed our mesocosm-based experimental design as sufficiently robust to investigate the utilization of 13C-DOC by sediment microbial communities. After 48 hours of incubation, PLFA-SIP identified heterotrophic α, β, and γ- proteobacteria and facultative anaerobic bacteria as the organisms primarily responsible for humic DOC consumption in streams and heterotrophic microeucaryotes as their predators. The evidence presented in this study shows a complex relationship between microbial community structure, environmental heterogeneity and utilization of humic DOC, indicating that humic DOC quality and quantity along with other hydro-ecological variables should be considered among the important factors that structure benthic microbial communities in lotic ecosystems.

Download or read book Microbial Metabolism of Dissolved Organic Carbon in Stream Hyporheic Zones written by William V. Sobczak and published by . This book was released on 1999 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bacterially mediated Carbon Dynamics in a Highly Impacted River Network written by Kelly J. Rodibaugh and published by . This book was released on 2012 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inland freshwater ecosystems, though comprising a small portion of the earth's surface, are thought to be important in the global carbon (C) cycle. Carbon processing by heterotrophic microbes (bacteria) is a critical process, contributing considerably to overall ecosystem production and processing of dissolved organic carbon (DOC). This study assesses spatial variation in C processing by heterotrophic bacterioplankton in a semi-arid river network: the Rio Grande/Rio Bravo del Norte in Texas, USA. I examined how bacterial metabolism and C processing varied with spatial differences in physicochemical conditions and patterns in DOC lability in this highly impacted riverine network. Physicochemical and biological data were collected at 14 sites from March - December of 2010. I additionally analyzed phytoplankton biomass, bacterial density, bacterial community metabolic rates [bacterial respiration (BR), bacterial productivity (BP), and bacterial growth efficiency (BGE)], and C quality parameters at a subset of nine sites within this drainage. Across the drainage, hydrology and landscape position (i.e., biogeoclimatic conditions, presence of reservoirs, and groundwater contribution to flow) substantially influenced in-stream physicochemical conditions, leading to spatial patterns in bacterial density, phytoplankton biomass, and bacterial metabolism. Bacterial C metabolism was influenced by both physicochemical and C quality - quantity gradients present within the drainage. Bacterial production and BR responded to different environmental gradients, with BP being driven by C quality and inorganic nutrients. This resulted in a negative correlation between BGE and the bacterial respiration of refractory C. Results from this study indicate that natural variation and anthropogenic impacts influence the physicochemical and biotic conditions across the Rio Grande/Rio Bravo del Norte drainage and these effects have implications for C sequestration, transformation, and transport, as well as for organic matter (OM) delivery to the Gulf of Mexico.

Download or read book Microbial and Geochemical Investigations of Dissolved Organic Carbon and Microbial Ecology of Native Waters from the Biscayne and Upper Floridan Aquifers written by John Thomas Lisle and published by . This book was released on 1957 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Bacterial Alteration and Removal of Dissolved Organic Matter in the Surface Ocean written by Byron Pedler Sherwood and published by . This book was released on 2014 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean contains one of the largest reservoirs of reduced carbon on Earth in the form of dissolved organic matter (DOM). Heterotrophic bacteria serve as the primary force regulating the degradation of this material, recycling the majority of dissolved organic carbon (DOC) produced in the surface ocean by phytoplankton back to carbon dioxide. While it is known that microbial community structure plays a role in determining the rate and magnitude of DOM turnover, the quantitative contribution of individuals to this process remains unknown. The objective of this dissertation was to investigate the constraints on DOM turnover by bacterial communities by focusing on how a single bacterial strain makes a living in the sea. I found that a single bacterial strain, Alteromonas sp. AltSIO, has the capacity to consume an equivalent magnitude of DOC as diverse bacterial communities, suggesting that bacterial diversity may not be required for the complete removal of labile DOC in the surface ocean. In long-term microcosms, however, bacterial diversity was required for continued degradation of semi-labile DOC. To test the generality of this capacity among individual bacteria, a culture-based study was conducted where >100 phylogenetically diverse bacterial strains were isolated to screen for growth in unamended seawater. No other bacterial strain tested exhibited the capacity to consume a measureable quantity of DOC when grown in isolation, suggesting that this phenomenon may not be common among readily culturable marine bacteria. Physiological investigations of this isolate reveal a broad capacity for processing carbohydrates, yet an apparent preference for disaccharides and inability to metabolize glucose. Genomic analysis confirmed that this strain lacks a glucose-specific permease required for the exogenous uptake of glucose, but is endowed with additional carbohydrate-specific transporters not found in genomes of closely related bacterial strains. Genomic insights also show the potential to reduce nitrate, a high capacity to scavenge iron, and a complete chemotaxis apparatus potentially used for disaccharide acquisition. DOM characterization by ultrahigh resolution mass spectrometry revealed that AltSIO and diverse seawater communities significantly alter the composition of ambient DOM.

Download or read book Influence of Geological Variation on Dissolved Organic Matter Quality and Microbial Community Structure in Forested Stream Sediments written by Jennifer June Mosher and published by . This book was released on 2008 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Utilization of Dissolved Organic Carbon by Heterotrophic Bacteria and Protozoa written by James M. Graham and published by . This book was released on 1979 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Dissolved Organic Carbon as a Bacterial Growth Substrate and as an Ultraviolet B Radiation Sunscreen for Aquatic Microbial Foodwebs in Mackenzie Delta Lakes Northwest Territories microform written by Christopher J. (Christopher John) Teichreb and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1999 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Inundation and Vegetation on Microbial Metabolism of Dissolved Organic Carbon written by Jennifer Denise Aiosa and published by . This book was released on 1996 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heterotrophic Response to Dissolved Organic Carbon in Aquatic Environments written by Gary S. Sayler and published by . This book was released on 1974 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved Organic Carbon Dynamics in Tallgrass Prairie Streams written by Sophie Alexandra Higgs and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Contrary to the previous notion that a stream acts primarily as the transporter of materials from land to oceans, research has shown that in-stream processing of organic matter and nutrients is significant and relevant at a global scale. Dissolved organic carbon (DOC) is the most abundant form of organic carbon in streams and has been demonstrated as an important source of energy supporting stream food webs. Understanding the dynamics of DOC in streams is, therefore, important in determining the contribution of flowing waters to global carbon storage and release. However, DOC exists as many different compounds, varying in source, composition, and quality. The composition of DOC that ends up in streams is partly controlled by the surrounding watershed, and landscape effects on DOC quality and quantity in streams have been observed. In the North American Tallgrass prairie, woody encroachment has led to changes in riparian vegetation, potentially altering the DOC received by the stream, and making it important to understand rates of DOC transformation as landscape alterations continue. The heterogeneity of the DOC pool makes it difficult to fully describe its components and to measure transformation rates. DOC uptake, or biological use, has been estimated through several methods including in-stream additions of various DOC sources and bottle incubations of stream water and sediments. One problem with addition methods for calculating uptake is that the DOC pool is difficult to replicate and additions of simple compounds or organic leachates do not represent total dissolved organic carbon (TDOC) dynamics. Another potential issue is that additions of a labile compound could potentially alter microbial activity through a priming effect and therefore distort ambient DOC uptake estimates. Finally, uptake parameters are mostly calculated assuming benthic uptake while recent studies have shown that planktonic uptake of DOC can also be significant. We conducted this study with these three considerations in mind. In the first chapter, we describe our use of in situ additions of glucose and bur oak leaf leachate in prairie stream reaches and concentrations of specific components to determine uptake dynamics of various specific DOC components, from a simple sugar to more complex plant compounds. We calculated uptake parameters of glucose and two different oak leaf components. We found that using glucose concentrations rather than TDOC concentrations, as has been done in previous studies, to measure uptake parameters resulted in higher uptake rates, indicating the importance of measuring the specific component added. Through leaf leachate additions, we found that an amino acid like component was consistently taken up faster than a humic-like component. The second chapter addresses the questions of uptake location and priming through a series of recirculating chamber incubations. We found that benthic uptake of leaf leachate was more important than that in the water column. Finally, elevated uptake of one leaf leachate component in the presence of glucose indicated a priming effect on microbial DOC uptake.

Download or read book Assessment of Microbial Carbon Processing and Its Implications to the Carbon Budget of Lake Superior written by Lindsey Michelle Koren and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few decades, there has been increased research focus on carbon cycling within aquatic systems, especially with the changing global climate. Inland waters play a major role in the global carbon cycle, but the fundamental features remain poorly understood, particularly the large lakes of the world. Our experimental approach assessing the carbon budget of Lake Superior, the largest freshwater lake by area, provides spatial and temporal variability that has been previously overlooked but may be critical to our understanding on the biogeochemical processes controlling the lake. Multiple stations were chosen across the lake, both nearshore and offshore, to evaluate the variability in physical mixing regimes and biogeochemical processing. Short and long-term carbon consumption measurements were coupled to assess the heterotrophic activity relative to the lability of dissolved organic carbon. Partial pressure of carbon dioxide (pCO2) was directly measured to determine the metabolic nature of the lake and the amount of carbon dioxide (CO2) that fluxes across the air-water interface. The pCO2 results were further coupled with an isotopic approach measuring oxygen-18 ([gamma]18O) to evaluate how the metabolism of Lake Superior has changed over a decadal scale. A range of environmental factors, including temperature, photodegradation and source/quality of organic carbon, influenced short and long-term carbon consumption. In-situ pCO2observations supported a temporal switch in metabolism from the lake being a source of CO2in the spring to being a sink in the summer driven by biological components of the system. When the pCO2 results were coupled with the isotopic measurements over the past decade (1999-2011), Lake Superior was dominated by respiration during isothermal conditions and production during stratification. In the past decade, Lake Superior has experienced increased surface water temperatures, shifting the metabolic state to a shorter net heterotrophic period in the spring and a longer net autotrophic period in the summer. This research highlights fundamental aspects of Lake Superior's metabolism that have been previously understudied, as well as providing key information about processes controlling its carbon budget, and giving a better understanding of how climate change will continue to impact Lake Superior.

Download or read book Effects of Inorganic Nutrients and Dissolved Organic Carbon on Oxygen Demand in Select Rivers in Northern Utah written by Joseph L Crawford and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Sewage, agricultural runoff, and atmospheric deposition have greatly increased the amount of nutrients (largely nitrogen (N) and phosphorus (P)) in surface water nationwide. Excess nutrients are associated with algal blooms and dissolved oxygen depletion in many water bodies, but linkages between nutrients and dissolved oxygen have been largely correlative. Biochemical oxygen demand (BOD) is a regulated water quality parameter that is aimed at describing the amount of oxygen consumed during the decomposition of organic matter. Despite the awareness that excess nutrients are linked to dissolved oxygen in rivers, few studies in the nutrient criteria literature discuss BOD measurements or how nutrients may impact BOD. Accordingly, I used factorial experiments to test the effect of inorganic nutrients (as N, P and N+P) and dissolved organic carbon on BOD measurements in Utah streams. The study was carried out from January through summer base flow in 2011, allowing me to evaluate the effects of spatial and temporal variation of ambient nutrient concentration on oxygen demand. The study design included measurements in streams above and below nutrient point-sources (publicly owned treatment works) and several reference sites. I used classification and regression trees to identify thresholds of TN and TP that separate BOD response to nutrients into statistically distinct groups. My results show that seasonal variation affected BOD levels. As temperatures rose and water levels increased during peak runoff, I observed the highest BOD response to nutrient additions. I also found a significant correlation between BOD and ambient nutrient concentrations during that time period. I identified potential nutrient-related thresholds that could be used to assign numeric criteria that would protect designated uses. The threshold values I found for TN and TP were 0.56 mg/L and 0.09 mg/L, respectively. My results suggest that BOD may be sensitive to nutrient inputs and my experimental approach could be used as one line of evidence to support nutrient criteria related to aquatic life uses.

Download or read book Effects of Dissolved Organic Carbon as a Bacterial Growth Substrate and as an Ultraviolet B Radiation Sunscreen for Aquatic Microbial Foodwebs in Mackenzie Delta Lakes Northwest Territories written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seasonal Dynamics and Temperature Effects on Microbial Utilizaion of Dissolved Organic Carbon in the Delaware Estuary written by Dawn M. Castle and published by . This book was released on 1997 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: