<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Porubsky, William P.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Moore, Willard S.</style></author><author><style face="normal" font="default" size="100%">Tuncay, Kagan</style></author><author><style face="normal" font="default" size="100%">Meile, Christof</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Field measurements and modeling of groundwater flow and biogeochemistry at Moses Hammock, a backbarrier island on the Georgia coast</style></title><secondary-title><style face="normal" font="default" size="100%">Biogeochemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/content/t18x02358tt6x123/</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">104</style></volume><pages><style face="normal" font="default" size="100%">69-90</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A combination of field measurements, laboratory experiments and model simulations were used to characterize the groundwater biogeochemical dynamics along a shallow monitoring well transect on a coastal hammock. A switch in the redox status of the dissolved inorganic nitrogen (DIN) pool in the well at the upland/saltmarsh interface occurred over the spring-neap tidal transition: the DIN pool was dominated by nitrate during spring tide and by ammonium during neap tide. A density-dependent reaction-transport model was used to investigate the relative importance of individual processes to the observed N redox-switch. The observed N redox-switch was evaluated with regard to the roles of nitrification, denitrification, dissimilatory nitrate reduction to ammonium (DNRA), ammonium adsorption, and variations in inflowing water geochemistry between spring and neap tides.Transport was driven by measured pressure heads and process parameterizations were derived from field observations, targeted laboratory experiments, and the literature. Modeling results suggest that the variation in inflow water chemistry was the dominant driver of DIN dynamics and highlight the importance of spring-neap tide variations in the high marsh, which influences groundwater biogeochemistry at the marsh-upland transition.</style></abstract><accession-num><style face="normal" font="default" size="100%">LTER.2011-93253</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Porubsky, William P.</style></author><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Benthic metabolism and the fate of dissolved inorganic nitrogen in intertidal sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Estuarine Coastal and Shelf Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1016/j.ecss.2009.04.012</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">83</style></volume><pages><style face="normal" font="default" size="100%">392-402</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We determined patterns of benthic metabolism and examined the relative importance of denitrification (DNF) and dissimilatory nitrate reduction to ammonium (DNRA) as sinks for nitrate (NO3&amp;#8722;) in intertidal sediments in the presence and absence of benthic microalgal (BMA) activity. By influencing the activity of BMA, light regulated the metabolic status of the sediments, and, in turn, exerted strong control on sediment nitrogen dynamics and the fate of inorganic nitrogen. A pulsed addition of 15N-labeled NO3&amp;#8722; tracked the effect and fate of dissolved inorganic nitrogen (DIN) in the system. Under illuminated conditions, BMA communities influenced benthic fluxes directly, via DIN uptake, and indirectly, by altering the oxygen penetration depth. Under dark hypoxic and anoxic conditions, the fate of water column NO3&amp;#8722; was determined largely by three competing dissimilatory reductive processes; DNF, DNRA, and, on one occasion, anaerobic ammonium oxidation (anammox). Mass balance of the added 15N tracer illustrated that DNF accounted for a maximum of 48.2% of the 15NO3&amp;#8722; reduced while DNRA (a minimum of 11.4%) and anammox (a minimum of 2.2%) accounted for much less. A slurry experiment was employed to further examine the partitioning between DNF and DNRA. High sulfide concentrations negatively impacted rates of both processes, while high DOC:NO3&amp;#8722; ratios favored DNRA over DNF.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2009-93322</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Cook, P.</style></author><author><style face="normal" font="default" size="100%">de Beer, D.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Brinson, Mark</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Biogeochemical dynamics of coastal tidal flats</style></title><secondary-title><style face="normal" font="default" size="100%">Coastal Wetlands: An Integrated Ecosystem Approach</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.elsevier.com/wps/find/bookdescription.cws_home/716674/description</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Elsevier</style></publisher><pub-location><style face="normal" font="default" size="100%">Amsterdam, The Netherlands</style></pub-location><pages><style face="normal" font="default" size="100%">345-374</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2009-93312</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lasher, Chris</style></author><author><style face="normal" font="default" size="100%">Dyszynski, Glen</style></author><author><style face="normal" font="default" size="100%">Everett, Karen</style></author><author><style face="normal" font="default" size="100%">Ye, Wendy</style></author><author><style face="normal" font="default" size="100%">Sheldon, Wade M.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Moran, Mary Ann</style></author><author><style face="normal" font="default" size="100%">Whitman, William B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The diverse bacterial community in intertidal, anaerobic sediments at Sapelo Island, Georgia</style></title><secondary-title><style face="normal" font="default" size="100%">Microbial Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/content/6743370258u06313/</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">58</style></volume><pages><style face="normal" font="default" size="100%">244-261</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The phylogenetic diversity and composition of the bacterial community in anaerobic sediments from Sapelo Island, GA, USA were examined using 16S rRNA gene libraries. The diversity of this community was comparable to that of soil, and 1,186 clones formed 817 OTUs at 99% sequence similarity. Chao1 estimators for the total richness were also high, at 3,290 OTUs at 99% sequence similarity. The program RDPquery was developed to assign clones to taxonomic groups based upon comparisons to the RDP database. While most clones could be assigned to describe phyla, fewer than 30% of the clones could be assigned to a described order. Similarly, nearly 25% of the clones were only distantly related (&lt;90% sequence similarity) to other environmental clones, illustrating the unique composition of this community. One quarter of the clones were related to one or more undescribed orders within the &amp;#947;-Proteobacteria. Other abundant groups included the &amp;#948;-Proteobacteria, Bacteroidetes, and Cyanobacteria. While these phyla were abundant in other estuarine sediments, the specific members at Sapelo Island appeared to be different from those previously described in other locations, suggesting that great diversity exists between as well as within estuarine intertidal sediments. In spite of the large differences in pore water chemistry with season and depth, differences in the bacterial community were modest over the temporal and spatial scales examined and generally restricted to only certain taxa.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2009-93315</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Craft, Christopher B.</style></author><author><style face="normal" font="default" size="100%">Clough, J.</style></author><author><style face="normal" font="default" size="100%">Ehman, J.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Park, R.</style></author><author><style face="normal" font="default" size="100%">Pennings, Steven C.</style></author><author><style face="normal" font="default" size="100%">Guo, Hongyu</style></author><author><style face="normal" font="default" size="100%">Machmuller, Megan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Forecasting the effects of accelerated sea level rise on tidal marsh ecosystem services</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Ecology and the Environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.esajournals.org/doi/abs/10.1890/070219</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">7</style></volume><pages><style face="normal" font="default" size="100%">73-78</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We used field and laboratory measurements, geographic information systems, and simulation modeling to investigate the potential effects of accelerated sea-level rise on tidal marsh area and delivery of ecosystem services along the Georgia coast. Model simulations using the Intergovernmental Panel on Climate Change (IPCC) mean and maximum estimates of sea-level rise for the year 2100 suggest that salt marshes will decline in area by 20% and 45%, respectively. The area of tidal freshwater marshes will increase by 2% under the IPCC mean scenario, but will decline by 39% under the maximum scenario. Delivery of ecosystem services associated with productivity (macrophyte biomass) and waste treatment (nitrogen accumulation in soil, potential denitrification) will also decline. Our findings suggest that tidal marshes at the lower and upper salinity ranges, and their attendant delivery of ecosystem services, will be most affected by accelerated sealevel rise, unless geomorphic conditions (ie gradual increase in elevation) enable tidal freshwater marshes to migrate inland, or vertical accretion of salt marshes to increase, to compensate for accelerated sea-level rise.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2009-93301</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Edmonds, Jennifer W.</style></author><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Mou, Xiaozhen</style></author><author><style face="normal" font="default" size="100%">Moran, Mary Ann</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial Community Response to Seawater Amendment in Low-Salinity Tidal Sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Microbial Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/content/44411m5237863955/</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">58</style></volume><pages><style face="normal" font="default" size="100%">558-568</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Rising sea levels and excessive water withdrawals upstream are making previously freshwater coastal ecosystems saline. Plant and animal responses to variation in the freshwater-saline interface have been well studied in the coastal zone; however, microbial community structure and functional response to seawater intrusion remains relatively unexplored. Here, we used molecular approaches to evaluate the response of the prokaryotic community to controlled changes in porewater salinity levels in freshwater sediments from the Altamaha River, Georgia, USA. This work is a companion to a previously published study describing results from an experiment using laboratory flow-through sediment core bioreactors to document biogeochemical changes as porewater salinity was increased from 0 to 10 over 35 days. As reported in Weston et al. (Biogeochemistry, 77:375-408, 62), porewater chemistry was monitored, and cores were sacrificed at 0, 9, 15, and 35 days, at which time we completed terminal restriction fragment length polymorphism and 16S rRNA clone library analyses of sediment microbial communities. The biogeochemical study documented changes in mineralization pathways in response to artificial seawater additions, with a decline in methanogenesis, a transient increase in iron reduction, and finally a dominance of sulfate reduction. Here, we report that, despite these dramatic and significant changes in microbial activity at the biogeochemical level, no significant differences were found between microbial community composition of control vs. seawater-amended treatments for either Bacterial or Archaeal members. Further, taxa in the seawater-amended treatment community did not become more &quot;marine-like&quot; through time. Our experiment suggests that, as seawater intrudes into freshwater sediments, observed changes in metabolic activity and carbon mineralization on the time scale of weeks are driven more by shifts in gene expression and regulation than by changes in the composition of the microbial community.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2009-93304</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Hollibaugh, James T.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Population growth away from the coastal zone: Thirty years of land use change and nutrient export from the Altamaha River, GA</style></title><secondary-title><style face="normal" font="default" size="100%">Science of the Total Environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1016/j.scitotenv.2008.12.066</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">407</style></volume><pages><style face="normal" font="default" size="100%">3347-3356</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We used more than thirty years of water quality monitoring data collected by the United States Geological Survey at several stations in the Altamaha River and its tributaries to examine the relationship between population density, agricultural land use, and nutrient export from the watershed. Population densities in the Altamaha River watershed increased during the study period, most notably in the upper watershed near metropolitan Atlanta, while agricultural land use declined throughout the watershed. NOx, TN and P in rivers were related to human population densities, while OC and NH+4 concentrations in rivers were apparently related to agricultural land use. A general pattern of increasing NOx and TN and decreasing NH4+, P and OC over time throughout the watershed reflected changing population and land use. The overall average load from the Altamaha River to the coastal zone during the study period was 1.1, 5.6,16.9,0.9 and 262 kmol km-2 yr-1, delivering 40,197, 596, 30, and 9213 106 mol yr-1 of NH4+, NOx, TN, P and OC, respectively, to the coastal zone. The nutrient export patterns suggest that N and P loading to rivers in the Altamaha River watershed was greatest in the upper watershed where high population densities were found, and in-stream processing, dilution, and only moderate inputs during transit through the lower watershed resulted in relatively low export from the watershed to coastal waters.</style></abstract><accession-num><style face="normal" font="default" size="100%">LTER.2009-93333</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Craft, Christopher B.</style></author><author><style face="normal" font="default" size="100%">Clough, J.</style></author><author><style face="normal" font="default" size="100%">Ehman, J.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Park, R.</style></author><author><style face="normal" font="default" size="100%">Pennings, Steven C.</style></author><author><style face="normal" font="default" size="100%">Guo, Hongyu</style></author><author><style face="normal" font="default" size="100%">Machmuller, Megan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">SLR and ecosystem services: a response to Kirwan and 	Guntenspergen.</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Ecology and the Environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://gce-lter.marsci.uga.edu/public/uploads/Craft_et_al_2009_Writeback_20120221T135811.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">7</style></volume><pages><style face="normal" font="default" size="100%">127-128</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2009-93302</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Iris  Anderson,</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Carpenter, Edward J.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Nitrogen Cycling in Estuarine and Nearshore Sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Nitrogen in the Marine Environment, Second Edition</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1016/B978-0-12-372522-6.00019-0</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Elsevier Inc.</style></publisher><pages><style face="normal" font="default" size="100%">867-915</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2008-93350</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Porubsky, William P.</style></author><author><style face="normal" font="default" size="100%">Velasquez, Liliana E.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nutrient replete benthic microalgae as a source of labile dissolved organic carbon to coastal waters</style></title><secondary-title><style face="normal" font="default" size="100%">Estuaries and Coasts</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/content/j6531n2472m364u4/?p=4887a9488d8a46098b68a028eafc3b71&amp;pi=0</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">31</style></volume><pages><style face="normal" font="default" size="100%">860-876</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Dissolved organic carbon (DOC) flux dynamics were examined in the context of other biogeochemical cycles in intertidal sediments inhabited by benthic microalgae. In August 2003, gross oxygenic photosynthetic (GOP) rates, oxygen penetration depths, and benthic flux rates were quantified at seven sites along the Duplin River, GA, USA. Sediments contained abundant benthic microalgal (BMA) biomass with a maximum chlorophyll a concentration of 201 mg chl a m-2. Oxygen microelectrodes were used to determine GOP rates and O2 penetration depth, which were tightly correlated with light intensity. Baseline and 15N-nitrate amended benthic flux core incubations were employed to quantify benthic fluxes and to investigate the impact of BMA on sediment water exchange under nitrogen (N)-limited and N-replete conditions. Unamended sediments exhibited tight coupling between GOP and respiration and served as a sink for water column dissolved inorganic nitrogen (DIN) and a source of silicate and dissolved inorganic carbon (DIC). The BMA response to the N addition indicated sequential nutrient limitation, with N limitation followed by silicate limitation. In diel (light</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2008-93359</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Edmonds, Jennifer W.</style></author><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Moran, Mary Ann</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Variation in Prokaryotic Community Composition as a Function of Resource Availability in Tidal Creek Sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Applied and Environmental Microbiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://aem.asm.org/cgi/content/abstract/74/6/1836</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">74</style></volume><pages><style face="normal" font="default" size="100%">1836-1844</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">n anaerobic coastal sediments, hydrolytic and/or fermentative bacteria degrade polymeric material and produce labile intermediates, which are used by terminal metabolizers to complete the conversion of organic material to CO2. We used molecular approaches to evaluate the response of two bacterial terminal metabolizer groups from a coastal tidal creek sediments, sulfate reducers and methanogens, to controlled changes in carbon resource supply. Tidal creek sediment bioreactors were established in April and August 2004. For each date, intact sediment sections were continuously supplied with flowthrough seawater that was either unamended or amended with the high-molecular-weight polysaccharide dextran. Biogeochemical data indicate that the activity of fermenting bacteria and the terminal metabolizers was limited by organic carbon supply during both experiments, with a significant increase in net volatile fatty acid (VFA) production and rates of sulfate reduction and methanogenesis following dextran addition. Community composition (measured by using terminal restriction fragment length polymorphism analysis, and functional gene [dsrA, mcrA] clone libraries) changed from April to August. However, community composition was not different between amended and unamended cores within each month, despite the change in resource level. Moreover, there was no relationship between community richness and evenness with resource level. This lack of variation in community composition with C addition could be attributed to the dynamic environment these sediment communities experience in situ. Fluctuations in VFA concentrations are most likely very high, so that the dominant bacterial species must be able to outcompete other species at both high and low resource levels.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2008-93341</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Moore, Willard S.</style></author><author><style face="normal" font="default" size="100%">Blanton, Jackson O.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Estimates of flushing times, submarine groundwater discharge, and nutrient fluxes to Okatee Estuary, South Carolina</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">111</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A physical model based on determining the fraction of the tidal prism that returns to the estuary on the next high tide is used to estimate the flushing time of the Okatee River estuary. The return flow factor (b) of 0.81 yields a flushing time of 2 days. A mass balance model of 228Ra and salinity is also used to estimate b. This model yields an average b = 0.79, virtually the same as the physical model. A third model based on the decay of 224Ra relative to 228Ra is used to determine the apparent age of water in the estuary. These ages range from 1.6 to 5 days, with an average of 3.4 days. These three independent estimates are in remarkably close agreement, certainly within the error of each estimate. We use these residence times to develop a mass balance model for the radium isotopes in the Okatee estuary. We consider decay, mixing, sedimentary input, river input, and submarine groundwater discharge (SGD). The major loss term for each isotope is mixing with water in Port Royal Sound; the major input for each isotope is SGD. At steady state these terms must balance. Knowing the water age and the radium isotope composition of groundwater entering the Okatee allows us to estimate an average SGD flux of 1 m3/s. The SGD flux is a factor of 3</style></abstract><issue><style face="normal" font="default" size="100%">C09006</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2006-93387</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Dixon, Ray E.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial and geochemical ramifications of salinity intrusion into tidal freshwater sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">111</style></volume><pages><style face="normal" font="default" size="100%">G01009</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The effects of salinity intrusion on the anaerobic microbial and geochemical dynamics of tidal freshwater sediments were investigated using flow-through sediment reactors. In freshwater control sediments, organic matter mineralization was dominated by methanogenesis (62%), followed by sulfate reduction (18%), denitrification (10%), and iron reduction (10%). Upon salinity intrusion, nutrient (ammonium, silicate, phosphate) concentrations increased and rates of methanogenesis declined. Iron-oxide bioavailability increased and microbial iron reduction appeared to account for &gt;60% of organic matter oxidation for several days after salinity intrusion. However, sulfate reduction was the dominant pathway (&gt;50%) of organic matter oxidation within 2 weeks of salinity intrusion, and accounted for &gt;95% of total organic matter mineralization after 4 weeks. Total in situ sediment organic matter mineralization doubled following salinity intrusion. Increased nutrient release, decreased methanogenesis and a rapid shift to sulfate reduction, with a coincident increase overall organic matter mineralization, accompanied salinity intrusion into previously freshwater riverine sediments.</style></abstract><accession-num><style face="normal" font="default" size="100%">LTER.2006-93397</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Porubsky, William P.</style></author><author><style face="normal" font="default" size="100%">Samarkin, Vladimir</style></author><author><style face="normal" font="default" size="100%">MacAvoy, Steven E.</style></author><author><style face="normal" font="default" size="100%">Erickson, Matthew</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Pore water stoichiometry of terminal metabolic products, sulfate, and dissolved organic carbon and nitrogen in intertidal creek-bank sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Biogeochemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">77</style></volume><pages><style face="normal" font="default" size="100%">375-408</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Porewater equilibration samplers were used to obtain porewater inventories of inorganic nutrients (NH4 +, NOx, PO4 3-), dissolved organic carbon (DOC) and nitrogen (DON), sulfate (SO4 2-), dissolved inorganic carbon (DIC), hydrogen sulfide (H2S), chloride (Cl-), methane (CH4) and reduced iron (Fe2+) in intertidal creek-bank sediments at eight sites in three estuarine systems over a range of salinities and seasons. Sulfate reduction (SR) rates and sediment particulate organic carbon (POC) and nitrogen (PON) were also determined at several of the sites. Four sites in the Okatee River estuary in South Carolina, two sites on Sapelo Island, Georgia and one site in White Oak Creek, Georgia appeared to be relatively pristine. The eighth site in Umbrella Creek, Georgia was directly adjacent to a small residential development employing septic systems to handle household waste. The large data set (&gt;700 porewater profiles) offers an opportunity to assess system-scale patterns of porewater biogeochemical dynamics with an emphasis on DOC and DON distributions. SO4 2- depletion (SO4 2-)Dep was used as a proxy for SR, and (SO4 2-)Dep patterns agreed with measured (35S) patterns of SR. There were significant system-scale correlations between the inorganic products of terminal metabolism (DIC, NH4 + and PO4 3-) and (SO4 2-)Dep, and SR appeared to be the dominant terminal carbon oxidation pathway in these sediments. Porewater inventories of DIC and (SO4 2-)Dep indicate a 2:1 stoichiometry across sites, and the C:N ratio of the organic matter undergoing mineralization was between 7.5 and 10. The data suggest that septic-derived dissolved organic matter with a C:N ratio below 6 fueled microbial metabolism and SR at a site with development in the upland. Seasonality was observed in the porewater inventories, but temperature alone did not adequately describe the patterns of (SO4 2-)Dep, terminal metabolic products (DIC, NH4 +, PO4 3-), DOC and DON, and SR observed in this study. It appears that production and consumption of labile DOC are tightly coupled in these sediments, and that bulk DOC is likely a recalcitrant pool. Preferential hydrolysis of PON relative to POC when overall organic matter mineralization rates were high appears to drive the observed patterns in POC:PON, DOC:DON and DIC:DIN ratios. These data, along with the weak seasonal patterns of SR and organic and inorganic porewater inventories, suggest that the rate of hydrolysis limits organic matter mineralization in these intertidal creek-bank sediments.</style></abstract><accession-num><style face="normal" font="default" size="100%">LTER.2006-93398</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Bronk, Deborah A.</style></author><author><style face="normal" font="default" size="100%">Koopmans, Dirk</style></author><author><style face="normal" font="default" size="100%">Moore, Willard S.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Rawson, Mac V.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Potential for groundwater-derived carbon, nitrogen and phosphorus inputs to coastal ecosystems in South Carolina and Georgia</style></title><secondary-title><style face="normal" font="default" size="100%">Implications of Land Use Change to Coastal Ecosystems</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><publisher><style face="normal" font="default" size="100%">Springer-Verlag</style></publisher><pub-location><style face="normal" font="default" size="100%">New York</style></pub-location><pages><style face="normal" font="default" size="100%">139-167</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2006-93384</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Magalh</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Moreira, R. M.</style></author><author><style face="normal" font="default" size="100%">Wiebe, William J.</style></author><author><style face="normal" font="default" size="100%">Bordalo, A. A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Effect of salinity and inorganic nitrogen concentrations on nitrification and denitri.cation rates in intertidal sediments and rocky bio.lms of the Douro River estuary, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Water Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><volume><style face="normal" font="default" size="100%">39</style></volume><pages><style face="normal" font="default" size="100%">1783</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The regulatory effects of salinity and inorganic nitrogen compounds on nitriflcation and denitrification were studied in intertidal sandy sediments and rocky biofilms in the Douro River estuary, Portugal, over a 12-month period. Nitrification and denitrification rates were measured in slurries of field samples and enrichment experiments using the difiuoromethane and the acetylene inhibition techniques, respectively. Salinity did not regulate denitrification in either environment, suggesting that halotolerant bacteria dominated the denitrifier communities. However, nitrification rates were stimulated when salinity increased from 0 to 15 practical salinity units. NO3- addition experiments revealed that NO3- availability stimulates denitrification rates in sandy sediments, but not in rocky biofilms; however, in rocky biofilms a positive and linear relationship was observed between denitrification rates and water column NO3- concentrations (r = 0.92) during the monthly surveys. The N2O:N2 ratios increased rapidly when NO3- increased from 63 to 363 uM; however, results from monthly surveys showed that environmental parameters other than NO3- availability may be important in controlling the variation in N2O production via denitrification. Ammonium additions to sandy sediments stimulated nitrification rates by 35% for the 20 uM NH4+ addition, but NH4+ appeared to inhibit nitrification at high concentration addition (200 uM NH4+). In contrast, rocky biofilm nitrification was stimulated by 65% when 200 uM NH4+ was added.</style></abstract><accession-num><style face="normal" font="default" size="100%">LTER.2005-93406</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Magalh</style></author><author><style face="normal" font="default" size="100%">Wiebe, William J.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Bordalo, A. A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Inorganic Nitrogen Dynamics in Intertidal Rocky Biofilms and Sediments of the Douro River Estuary (Portugal)</style></title><secondary-title><style face="normal" font="default" size="100%">Estuaries</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">592-607</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this study rates of oxygen, ammonium (NH4+), nitrate (NO3-), nitrite (NO2-), and nitrous oxide (N2O) fluxes, nitrogen (N) fixation, nitrification, and denitrification were compared between two intertidal sites for which there is an abundant global literature, muddy and sandy sediments, and two sites representing the rocky intertidal zone where biogeochemical processes have scarcely been investigated. In almost all sites oxygen production rates greatly exceeded oxygen consumption rates. During daylight, NH4+ and NO3- uptake rates together with ammonification could supply the different N requirements of the primary producer communities at all four sites; N assimilation by benthic or epilithic primary producers was the major process of dissolved inorganic nitrogen (DIN) removal; N fixation, nitrification, and denitrification were minor processes in the overall light DIN cycle. At night, distinct DIN cycling processes took place in the four environments, denitrification rates ranged from 9 +/- 2 to 360 +/- 30 mmol N2 m^-2 h^-1, accounting for 10</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2005-93407</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Temperature-driven decoupling of key phases of organic matter degradation in marine sediments</style></title><secondary-title><style face="normal" font="default" size="100%">Proceedings of the National Academy of Sciences (USA)</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.pnas.org/cgi/content/full/102/47/17036?maxtoshow=&amp;HITS=10&amp;hits=10&amp;RESULTFORMAT=&amp;fulltext=weston+%2B+joye&amp;searchid=1136415104224_10182&amp;FIRSTINDEX=0&amp;journalcode=pnas</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">102</style></volume><pages><style face="normal" font="default" size="100%">17036-17040</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The long-term burial of organic carbon in sediments results in the net accumulation of oxygen in the atmosphere, thereby mediating the redox state of the Earth's biosphere and atmosphere. Sediment microbial activity plays a major role in determining whether particulate organic carbon is recycled or buried. A diverse consortium of microorganisms that hydrolyze, ferment, and terminally oxidize organic compounds mediates anaerobic organic matter mineralization in anoxic sediments. Variable temperature regulation of the sequential processes, leading from the breakdown of complex particulate organic carbon to the production and subsequent consumption of labile, low-molecular weight, dissolved intermediates, could play a key role in controlling rates of overall organic carbon mineralization. We examined sediment organic carbon cycling in a sediment slurry and in flow through bioreactor experiments. The data show a variable temperature response of the microbial functional groups mediating organic matter mineralization in anoxic marine sediments, resulting in the temperature-driven decoupling of the production and consumption of organic intermediates. This temperature-driven decoupling leads to the accumulation of labile, low-molecular weight, dissolved organic carbon at low temperatures and low-molecular weight dissolved organic carbon limitation of terminal metabolism at higher temperatures.</style></abstract><issue><style face="normal" font="default" size="100%">47</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2005-93424</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Porubsky, William P.</style></author><author><style face="normal" font="default" size="100%">Weston, Nathaniel B.</style></author><author><style face="normal" font="default" size="100%">Lee, Rosalynn Y.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Rullk</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Benthic microalgal production and nutrient dynamics in intertidal sediments</style></title><secondary-title><style face="normal" font="default" size="100%">BioGeoChemistry of Tidal Flats</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year></dates><publisher><style face="normal" font="default" size="100%">Forschungszentrum Terramare Berichte Nr. 12, Proceedings of a Workshop held at the Hanse Institute of Advanced Study</style></publisher><pub-location><style face="normal" font="default" size="100%">Delmenhorst, Germany</style></pub-location><pages><style face="normal" font="default" size="100%">67-70</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2003-93454</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Collins, G.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Denitrification in the Marine Environment</style></title><secondary-title><style face="normal" font="default" size="100%">Encyclopedia of Environmental Microbiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><publisher><style face="normal" font="default" size="100%">John Wiley &amp; Sons, Inc.</style></publisher><pub-location><style face="normal" font="default" size="100%">New York</style></pub-location><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER.2002-93469</style></accession-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Moore, Willard S.</style></author><author><style face="normal" font="default" size="100%">Krest, James</style></author><author><style face="normal" font="default" size="100%">Taylor, Glenn</style></author><author><style face="normal" font="default" size="100%">Roggenstein, Edward</style></author><author><style face="normal" font="default" size="100%">Joye, Samantha B.</style></author><author><style face="normal" font="default" size="100%">Lee, Rosalynn Y.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Thermal evidence of water exchange through a coastal aquifer: implications for nutrient fluxes</style></title><secondary-title><style face="normal" font="default" size="100%">Geophysical Research Letters</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">GCE</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">29</style></volume><pages><style face="normal" font="default" size="100%">1704</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We report the discovery of a semi-confined, high permeability zone (HPZ) 2 meters below the sea bed where exchanges between coastal aquifers and the ocean occur. A temperature probe placed in the HPZ recorded a 1</style></abstract><issue><style face="normal" font="default" size="100%">14</style></issue><accession-num><style face="normal" font="default" size="100%">LTER.2002-93470</style></accession-num></record></records></xml>