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Biogeochemistry

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https://www.readbyqxmd.com/read/27918615/top-down-control-of-methane-emission-and-nitrogen-cycling-by-waterfowl
#1
R Scott Winton, Curtis J Richardson
Aquatic herbivores impose top-down control on the structure of wetland ecosystems, but the biogeochemical consequences of herbivory on methane (CH4 ) and nitrogen (N) are poorly known. To investigate the top-down effects of waterfowl on wetland biogeochemistry, we implemented exclosure experiments in a major waterfowl overwintering wetland in the southeastern United States over two growing seasons. We found that herbivory inhibited the oxidation of CH4 , leading to a mean increase in emission by 230% over control plots, and prevented nitrification, as indicated by low nitrate availability and undetectable emissions of nitrous oxide...
November 4, 2016: Ecology
https://www.readbyqxmd.com/read/27916135/integrating-chemical-imaging-of-cationic-trace-metal-solutes-and-ph-into-a-single-hydrogel-layer
#2
Christoph Hoefer, Jakob Santner, Sergey M Borisov, Walter W Wenzel, Markus Puschenreiter
Gel-based, two-dimensional (2D) chemical imaging techniques are versatile methods for investigating biogeochemically active environments at high spatial resolution (sub-mm). State-of-the-art solute imaging techniques, such as diffusive gradients in thin films (DGT) and planar optodes (PO), employ passive solute sampling or sensing. Combining these methods will provide powerful tools for studying the biogeochemistry of biological niches in soils and sediments. In this study we aimed at developing a combined single-layer gel for direct pH imaging using PO and sampling of anionic and cationic solutes by DGT, with subsequent analysis of the bound solutes by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)...
January 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27913016/biogenic-silica-composition-and-%C3%AE-13-c-abundance-in-the-changjiang-yangtze-and-huanghe-yellow-rivers-with-implications-for-the-silicon-cycle
#3
Xiangbin Ran, Bochao Xu, Jun Liu, Chenying Zhao, Sen Liu, Jiaye Zang
The study was carried out to address a method for separation of terrestrial and marine biogenic silica (BSi) in estuaries based on BSi compositions and δ(13)C values in BSi associated organic matter (δ(13)CBSi). We used two world-class major rivers - the Changjiang (Yangtze) and Huanghe (Yellow) Rivers as examples to illustrate our approach. Our results for these rivers indicate that riverine BSi is comprised mainly of phytoliths and diatoms. River BSi concentrations vary with terrestrial inputs and in-stream primary production...
November 29, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27905613/unambiguous-identification-and-discovery-of-bacterial-siderophores-by-direct-injection-21-tesla-fourier-transform-ion-cyclotron-resonance-mass-spectrometry
#4
Lawrence R Walker, Malak M Tfaily, Jared B Shaw, Nancy J Hess, Ljiljana Paša-Tolić, David W Koppenaal
Under iron-limiting conditions, bacteria produce low molecular mass Fe(iii) binding molecules known as siderophores to sequester the Fe(iii), along with other elements, increasing their bioavailability. Siderophores are thought to influence iron cycling and biogeochemistry in both marine and terrestrial ecosystems and hence the need for rapid, confident characterization of these compounds has increased. In this study, the type of siderophores produced by two marine bacterial species, Synechococcus sp. PCC 7002 and Vibrio cyclitrophicus 1F53, were characterized by use of a newly developed 21 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR MS) with direct injection electrospray ionization...
December 1, 2016: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/27905445/biogeochemistry-projections-of-the-soil-carbon-deficit
#5
Eric A Davidson
No abstract text is available yet for this article.
November 30, 2016: Nature
https://www.readbyqxmd.com/read/27902405/microbial-nanowires-an-electrifying-tale
#6
Sandeep K Sure, Leigh M Ackland, Angel A Torriero, Alok Adholeya, Mandira Kochar
Electromicrobiology has gained momentum in the last ten years with advances in microbial fuel cells and the discovery of microbial nanowires (MNWs). The list of MNWs producing microorganisms is growing and providing intriguing insights into the presence of such microorganisms in diverse environments and the potential roles MNWs can perform. This review discusses the MNWs produced by different microorganisms, including their structure, composition and role in electron transfer through MNWs. Two hypotheses, metallic-like conductivity and an electron hopping model, have been proposed for electron transfer and we present a current understanding of both these hypotheses...
October 21, 2016: Microbiology
https://www.readbyqxmd.com/read/27898193/modeling-long-term-changes-in-tundra-carbon-balance-following-wildfire-climate-change-and-potential-nutrient-addition
#7
Yueyang Jiang, Edward B Rastetter, Gaius R Shaver, Adrian V Rocha, Qianlai Zhuang, Bonnie L Kwiatkowski
To investigate the underlying mechanisms that control long-term recovery of tundra carbon (C) and nutrients after fire, we employed the Multiple Element Limitation (MEL) model to simulate 200-yr post-fire changes in the biogeochemistry of three sites along a burn severity gradient in response to increases in air temperature, CO2 concentration, nitrogen (N) deposition, and phosphorus (P) weathering rates. The simulations were conducted for severely burned, moderately burned, and unburned arctic tundra. Our simulations indicated that recovery of C balance after fire was mainly determined by the internal redistribution of nutrients among ecosystem components (controlled by air temperature), rather than the supply of nutrients from external sources (e...
August 4, 2016: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/27871750/biogeochemical-and-hydrological-drivers-of-the-dynamics-of-vibrio-species-in-two-patagonian-estuaries
#8
Germán A Kopprio, M Eugenia Streitenberger, Kentaro Okuno, Mónica Baldini, Florencia Biancalana, Anna Fricke, Ana Martínez, Sucharit B Neogi, Boris P Koch, Shinji Yamasaki, Rubén J Lara
The ecology of the most relevant Vibrio species for human health and their relation to water quality and biogeochemistry were studied in two estuaries in Argentinian Patagonia. Vibrio cholerae and Vibrio parahaemolyticus were reported in >29% of cases at the Río Colorado and Río Negro estuaries. Neither the pandemic serogroups of Vibrio cholerae O1, Vibrio cholerae O139 nor the cholera toxin gene were detected in this study. However, several strains of V. cholerae (not O1 or O139) are able to cause human disease or acquire pathogenic genes by horizontal transfer...
November 18, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27867233/influence-of-anthropogenic-aerosol-deposition-on-the-relationship-between-oceanic-productivity-and-warming
#9
Rong Wang, Yves Balkanski, Laurent Bopp, Olivier Aumont, Olivier Boucher, Philippe Ciais, Marion Gehlen, Josep Peñuelas, Christian Ethé, Didier Hauglustaine, Bengang Li, Junfeng Liu, Feng Zhou, Shu Tao
Satellite data and models suggest that oceanic productivity is reduced in response to less nutrient supply under warming. In contrast, anthropogenic aerosols provide nutrients and exert a fertilizing effect, but its contribution to evolution of oceanic productivity is unknown. We simulate the response of oceanic biogeochemistry to anthropogenic aerosols deposition under varying climate from 1850 to 2010. We find a positive response of observed chlorophyll to deposition of anthropogenic aerosols. Our results suggest that anthropogenic aerosols reduce the sensitivity of oceanic productivity to warming from -15...
December 28, 2015: Geophysical Research Letters
https://www.readbyqxmd.com/read/27859966/effects-of-three-global-change-drivers-on-terrestrial-c-n-p-stoichiometry-a-global-synthesis
#10
Kai Yue, Dario A Fornara, Wanqin Yang, Yan Peng, Zhijie Li, Fuzhong Wu, Changhui Peng
Over the last few decades there has been an increasing number of controlled-manipulative experiments to investigate how plants and soils might respond to global change. These experiments typically examined the effects of each of three global change drivers (i.e. nitrogen (N) deposition, warming, and elevated CO2 ) on primary productivity and on the biogeochemistry of carbon (C), N and phosphorus (P) across different terrestrial ecosystems. Here we capitalize on this large amount of information by performing a comprehensive meta-analysis (>2000 case studies worldwide) to address how C:N:P stoichiometry of plants, soils and soil microbial biomass might respond to individual vs...
November 17, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27847183/management-effects-on-greenhouse-gas-dynamics-in-fen-ditches
#11
Mike Peacock, Luke M Ridley, Chris D Evans, Vincent Gauci
Globally, large areas of peatland have been drained through the digging of ditches, generally to increase agricultural production. By lowering the water table it is often assumed that drainage reduces landscape-scale emissions of methane (CH4) into the atmosphere to negligible levels. However, drainage ditches themselves are known to be sources of CH4 and other greenhouse gases (GHGs), but emissions data are scarce, particularly for carbon dioxide (CO2) and nitrous oxide (N2O), and show high spatial and temporal variability...
November 12, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27822545/proteome-remodeling-in-response-to-sulfur-limitation-in-candidatus-pelagibacter-ubique
#12
Daniel P Smith, Carrie D Nicora, Paul Carini, Mary S Lipton, Angela D Norbeck, Richard D Smith, Stephen J Giovannoni
The alphaproteobacterium "Candidatus Pelagibacter ubique" strain HTCC1062 and most other members of the SAR11 clade lack genes for assimilatory sulfate reduction, making them dependent on organosulfur compounds that occur naturally in seawater. To investigate how these cells adapt to sulfur limitation, batch cultures were grown in defined medium containing either limiting or nonlimiting amounts of dimethylsulfoniopropionate (DMSP) as the sole sulfur source. Protein and mRNA expression were measured before, during, and after the transition from exponential growth to stationary phase...
July 2016: MSystems
https://www.readbyqxmd.com/read/27822538/diversity-and-activity-of-communities-inhabiting-plastic-debris-in-the-north-pacific-gyre
#13
Jessica A Bryant, Tara M Clemente, Donn A Viviani, Allison A Fong, Kimberley A Thomas, Paul Kemp, David M Karl, Angelicque E White, Edward F DeLong
Marine plastic debris has become a significant concern in ocean ecosystems worldwide. Little is known, however, about its influence on microbial community structure and function. In 2008, we surveyed microbial communities and metabolic activities in seawater and on plastic on an oceanographic expedition through the "great Pacific garbage patch." The concentration of plastic particles in surface seawater within different size classes (2 to 5 mm and >5 mm) ranged from 0.35 to 3.7 particles m(-3) across sampling stations...
May 2016: MSystems
https://www.readbyqxmd.com/read/27808458/a-longer-vernal-window-the-role-of-winter-coldness-and-snowpack-in-driving-spring-transitions-and-lags
#14
Alexandra R Contosta, Alden Adolph, Denise Burchsted, Elizabeth Burakowski, Mark Green, David Guerra, Mary Albert, Jack Dibb, Mary Martin, William H McDowell, Michael Routhier, Cameron Wake, Rachel Whitaker, Wilfred Wollheim
Climate change is altering the timing and duration of the vernal window, a period that marks the end of winter and the start of the growing season when rapid transitions in ecosystem energy, water, nutrient, and carbon dynamics take place. Research on this period typically captures only a portion of the ecosystem in transition and focuses largely on the dates by which the system wakes up. Previous work has not addressed lags between transitions that represent delays in energy, water, nutrient, and carbon flows...
November 3, 2016: Global Change Biology
https://www.readbyqxmd.com/read/27808101/the-formation-of-the-ocean-s-anthropogenic-carbon-reservoir
#15
Daniele Iudicone, Keith B Rodgers, Yves Plancherel, Olivier Aumont, Takamitsu Ito, Robert M Key, Gurvan Madec, Masao Ishii
The shallow overturning circulation of the oceans transports heat from the tropics to the mid-latitudes. This overturning also influences the uptake and storage of anthropogenic carbon (Cant). We demonstrate this by quantifying the relative importance of ocean thermodynamics, circulation and biogeochemistry in a global biochemistry and circulation model. Almost 2/3 of the Cant ocean uptake enters via gas exchange in waters that are lighter than the base of the ventilated thermocline. However, almost 2/3 of the excess Cant is stored below the thermocline...
November 3, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27790189/photosynthetic-versatility-in-the-genome-of-geitlerinema-sp-pcc-9228-formerly-oscillatoria-limnetica-solar-lake-a-model-anoxygenic-photosynthetic-cyanobacterium
#16
Sharon L Grim, Gregory J Dick
Anoxygenic cyanobacteria that use sulfide as the electron donor for photosynthesis are a potentially influential but poorly constrained force on Earth's biogeochemistry. Their versatile metabolism may have boosted primary production and nitrogen cycling in euxinic coastal margins in the Proterozoic. In addition, they represent a biological mechanism for limiting the accumulation of atmospheric oxygen, especially before the Great Oxidation Event and in the low-oxygen conditions of the Proterozoic. In this study, we describe the draft genome sequence of Geitlerinema sp...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27789839/dissolved-organic-sulfur-in-the-ocean-biogeochemistry-of-a-petagram-inventory
#17
Kerstin B Ksionzek, Oliver J Lechtenfeld, S Leigh McCallister, Philippe Schmitt-Kopplin, Jana K Geuer, Walter Geibert, Boris P Koch
Although sulfur is an essential element for marine primary production and critical for climate processes, little is known about the oceanic pool of nonvolatile dissolved organic sulfur (DOS). We present a basin-scale distribution of solid-phase extractable DOS in the East Atlantic Ocean and the Atlantic sector of the Southern Ocean. Although molar DOS versus dissolved organic nitrogen (DON) ratios of 0.11 ± 0.024 in Atlantic surface water resembled phytoplankton stoichiometry (sulfur/nitrogen ~ 0.08), increasing dissolved organic carbon (DOC) versus DOS ratios and decreasing methionine-S yield demonstrated selective DOS removal and active involvement in marine biogeochemical cycles...
October 28, 2016: Science
https://www.readbyqxmd.com/read/27753237/variable-depth-distribution-of-trichodesmium-clades-in-the-north-pacific-ocean
#18
Mónica Rouco, Sheean T Haley, Harriet Alexander, Samuel T Wilson, David M Karl, Sonya T Dyhrman
Populations of nitrogen-fixing cyanobacteria in the genus Trichodesmium are critical to ocean ecosystems, yet predicting patterns of Trichodesmium distribution and their role in ocean biogeochemistry is an ongoing challenge. This may, in part, be due to differences in the physiological ecology of Trichodesmium species, which are not typically considered independently in field studies. In this study, the abundance of the two dominant Trichodesmium clades (Clade I and Clade III) was investigated during a survey at Station ALOHA in the North Pacific Subtropical Gyre (NPSG) using a clade-specific qPCR approach...
October 18, 2016: Environmental Microbiology Reports
https://www.readbyqxmd.com/read/27742439/spatial-variation-in-the-accumulation-of-pops-and-mercury-in-bottlenose-dolphins-of-the-lower-florida-keys-and-the-coastal-everglades-south-florida
#19
France Damseaux, Jeremy J Kiszka, Michael R Heithaus, George Scholl, Gauthier Eppe, Jean-Pierre Thomé, Jennifer Lewis, Wensi Hao, Michaël C Fontaine, Krishna Das
The bottlenose dolphin (Tursiops truncatus) is an upper trophic level predator and the most common cetacean species found in nearshore waters of southern Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDXs, HCHs, HCB, Σ PCDD/Fs and Σ DL-PCBs) in blubber samples of bottlenose dolphins from LFK (n = 27) and FCE (n = 24)...
January 2017: Environmental Pollution
https://www.readbyqxmd.com/read/27730713/how-lichens-impact-on-terrestrial-community-and-ecosystem-properties
#20
Johan Asplund, David A Wardle
Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes...
October 11, 2016: Biological Reviews of the Cambridge Philosophical Society
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