24 results match your criteria Biogeochemistry[Journal]

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Spatially Variable Bioturbation and Physical Mixing Drive the Sedimentary Biogeochemical Seascape in the Louisiana Continental Shelf Hypoxic Zone.

Biogeochemistry 2019 ;143(2):151-169

United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, 1 Sabine Island Drive, Gulf Breeze FL 32561.

Seasonal hypoxia on the Louisiana continental shelf (LCS) has grown to over 22,000 km with limited information available on how low oxygen effects the benthos. Benthic macrofaunal colonization and sediment biogeochemical parameters were characterized at twelve stations in waters 10 - 50 m deep along four transects spanning 320 km across the LCS hypoxic zone in the early fall of 2010 when bottom waters typically return to oxic conditions. Chemical data and sediment profile imaging (SPI) support three primary mechanistic pathways of organic matter degradation on the LCS: (i) metal oxide cycling in depositional muds, (ii) infauna-driven bioturbation delivering oxygen below the sediment-water interface, and (iii) sulfate reduction in sediments where iron oxide availability is limited. Read More

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http://dx.doi.org/10.1007/s10533-019-00539-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541407PMC
January 2019
2 Reads

Spatial variability of organic matter properties determines methane fluxes in a tropical forested peatland.

Biogeochemistry 2019 26;142(2):231-245. Epub 2018 Nov 26.

1School of Biosciences, University of Nottingham, Nottingham, NG7 2RD UK.

Tropical peatland ecosystems are a significant component of the global carbon cycle and feature a range of distinct vegetation types, but the extent of links between contrasting plant species, peat biogeochemistry and greenhouse gas fluxes remains unclear. Here we assessed how vegetation affects small scale variation of tropical peatland carbon dynamics by quantifying in situ greenhouse gas emissions over 1 month using the closed chamber technique, and peat organic matter properties using Rock-Eval 6 pyrolysis within the rooting zones of canopy palms and broadleaved evergreen trees. Mean methane fluxes ranged from 0. Read More

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http://dx.doi.org/10.1007/s10533-018-0531-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383829PMC
November 2018
1 Read

Differential effects of chronic and acute simulated seawater intrusion on tidal freshwater marsh carbon cycling.

Biogeochemistry 2018 ;138(2):137-154

School of Public and Environmental Affairs, Indiana University, Bloomington, USA.

Tidal freshwater ecosystems experience acute seawater intrusion associated with periodic droughts, but are expected to become chronically salinized as sea level rises. Here we report the results from an experimental manipulation in a tidal freshwater marsh on the Altamaha River, GA where diluted seawater was added to replicate marsh plots on either a press (constant) or pulse (2 months per year) basis. We measured changes in porewater chemistry (SO, Cl, organic C, inorganic nitrogen and phosphorus), ecosystem CO and CH exchange, and microbial extracellular enzyme activity. Read More

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http://dx.doi.org/10.1007/s10533-018-0436-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750722PMC
January 2018

Watershed 'Chemical Cocktails': Forming Novel Elemental Combinations in Anthropocene Fresh Waters.

Biogeochemistry 2018 ;141(3):281-305

US Forest Service, Northern Research Station, Baltimore Field Station, Baltimore, Maryland 21228, USA.

In the Anthropocene, watershed chemical transport is increasingly dominated by novel combinations elements, which are hydrologically linked together as 'chemical cocktails.' Chemical cocktails are novel because human activities greatly enhance elemental concentrations and their probability for biogeochemical interactions and shared transport along hydrologic flowpaths. A new chemical cocktail approach advances our ability to: trace contaminant mixtures in watersheds, develop chemical proxies with high-resolution sensor data, and manage multiple water quality problems. Read More

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http://dx.doi.org/10.1007/s10533-018-0502-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699637PMC
January 2018
1 Read

Arsenic and high affinity phosphate uptake gene distribution in shallow submarine hydrothermal sediments.

Biogeochemistry 2018 20;141(1):41-62. Epub 2018 Sep 20.

5Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimiopolis Zographou, 157 84 Athens, Greece.

The toxicity of arsenic (As) towards life on Earth is apparent in the dense distribution of genes associated with As detoxification across the tree of life. The ability to defend against As is particularly vital for survival in As-rich shallow submarine hydrothermal ecosystems along the Hellenic Volcanic Arc (HVA), where life is exposed to hydrothermal fluids containing up to 3000 times more As than present in seawater. We propose that the removal of dissolved As and phosphorus (P) by sulfide and Fe(III)(oxyhydr)oxide minerals during sediment-seawater interaction, produces nutrient-deficient porewaters containing < 2. Read More

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http://link.springer.com/10.1007/s10533-018-0500-8
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http://dx.doi.org/10.1007/s10533-018-0500-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6413627PMC
September 2018
13 Reads

The impact of flooding on aquatic ecosystem services.

Biogeochemistry 2018 11;141(3):439-461. Epub 2018 May 11.

11Department of Biology, Trent University, Peterborough, ON Canada.

Flooding is a major disturbance that impacts aquatic ecosystems and the ecosystem services that they provide. Predicted increases in global flood risk due to land use change and water cycle intensification will likely only increase the frequency and severity of these impacts. Extreme flooding events can cause loss of life and significant destruction to property and infrastructure, effects that are easily recognized and frequently reported in the media. Read More

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http://dx.doi.org/10.1007/s10533-018-0449-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404734PMC
May 2018
15 Reads

Rapid warming and salinity changes in the Gulf of Maine alter surface ocean carbonate parameters and hide ocean acidification.

Biogeochemistry 2018 12;141(3):401-418. Epub 2018 Oct 12.

Ocean Process Analysis Laboratory, University of New Hampshire, Durham, NH 03824 USA.

A profound warming event in the Gulf of Maine during the last decade has caused sea surface temperatures to rise to levels exceeding any earlier observations recorded in the region over the last 150 years. This event dramatically affected CO solubility and, in turn, the status of the sea surface carbonate system. When combined with the concomitant increase in sea surface salinity and assumed rapid equilibration of carbon dioxide across the air sea interface, thermodynamic forcing partially mitigated the effects of ocean acidification for pH, while raising the saturation index of aragonite ( ) by an average of 0. Read More

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http://dx.doi.org/10.1007/s10533-018-0505-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404729PMC
October 2018
17 Reads

Alternative futures of dissolved inorganic nitrogen export from the Mississippi River Basin: influence of crop management, atmospheric deposition, and population growth.

Biogeochemistry 2017 May;133(3):263-277

Office of Research and Development, National Health and Environmental Effects Research Laboratory, Western Ecology Division, U. S. Environmental Protection Agency, Corvallis, OR, USA.

Nitrogen (N) export from the Mississippi River Basin contributes to seasonal hypoxia in the Gulf of Mexico (GOM). We explored monthly dissolved inorganic N (DIN) export to the GOM for a historical year (2002) and two future scenarios (year 2022) by linking macroeonomic energy, agriculture market, air quality, and agriculture land management models to a DIN export model. Future scenarios considered policies aimed at encouraging bioenergy crop production and reducing atmospheric N-emissions, as well as the effect of population growth and the states' infrastructure plans on sewage fluxes. Read More

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http://dx.doi.org/10.1007/s10533-017-0331-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6260936PMC
May 2017
2 Reads

Nitrogen dynamics and phytoplankton community structure: the role of organic nutrients.

Biogeochemistry 2017 15;134(1):125-145. Epub 2017 Jun 15.

1Scottish Association for Marine Science, Argyll, Oban, PA37 1QA Scotland, UK.

Dissolved organic nitrogen (DON) is recognised as an important N source for phytoplankton. However, its relative importance for phytoplankton nutrition and community composition has not been studied comprehensively. This study, conducted in a typical Scottish fjord, representative of near-pristine coastal environments, evaluates the utilisation of DON and dissolved inorganic nitrogen (DIN) by different microbial size fractions and the relationship of phytoplankton community composition with DON and other parameters. Read More

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http://dx.doi.org/10.1007/s10533-017-0351-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6979524PMC

Predicting the standing stock of organic carbon in surface sediments of the North-West European continental shelf.

Biogeochemistry 2017 15;135(1):183-200. Epub 2017 Feb 15.

1Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, Suffolk, NR33 0HT UK.

Shelf seas and their associated benthic habitats represent key systems in the global carbon cycle. However, the quantification of the related stocks and flows of carbon are often poorly constrained. To address benthic carbon storage in the North-West European continental shelf, we have spatially predicted the mass of particulate organic carbon (POC) stored in the top 10 cm of shelf sediments in parts of the North Sea, English Channel and Celtic Sea using a Random Forest model, POC measurements on surface sediments from those seas and relevant predictor variables. Read More

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http://dx.doi.org/10.1007/s10533-017-0310-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961524PMC
February 2017

Comparing benthic biogeochemistry at a sandy and a muddy site in the Celtic Sea using a model and observations.

Biogeochemistry 2017 7;135(1):155-182. Epub 2017 Sep 7.

1Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, NR33 0HT UK.

Results from a 1D setup of the European Regional Seas Ecosystem Model (ERSEM) biogeochemical model were compared with new observations collected under the UK Shelf Seas Biogeochemistry (SSB) programme to assess model performance and clarify elements of shelf-sea benthic biogeochemistry and carbon cycling. Observations from two contrasting sites (muddy and sandy) in the Celtic Sea in otherwise comparable hydrographic conditions were considered, with the focus on the benthic system. A standard model parameterisation with site-specific light and nutrient adjustments was used, along with modifications to the within-seabed diffusivity to accommodate the modelling of permeable (sandy) sediments. Read More

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http://dx.doi.org/10.1007/s10533-017-0367-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961523PMC
September 2017

Mediation of nitrogen by post-disturbance shelf communities experiencing organic matter enrichment.

Biogeochemistry 2017 29;135(1):135-153. Epub 2017 Aug 29.

3Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH UK.

Microbes and benthic macro-invertebrates interact in sediments to play a major role in the biogeochemical cycling of organic matter, but the extent to which their contributions are modified following natural and anthropogenic changes has received little attention. Here, we investigate how nitrogen transformations, ascertained from changes in archaeal and bacterial N-cycling microbes and water macronutrient concentrations ([NH-N], [NO-N], [NO-N]), in sand and sandy mud sediments differ when macrofaunal communities that have previously experienced contrasting levels of chronic fishing disturbance are exposed to organic matter enrichment. We find that differences in macrofaunal community structure related to differences in fishing activity affect the capacity of the macrofauna to mediate microbial nitrogen cycling in sand, but not in sandy mud environments. Read More

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http://dx.doi.org/10.1007/s10533-017-0370-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961516PMC

Mediation of macronutrients and carbon by post-disturbance shelf sea sediment communities.

Biogeochemistry 2017 12;135(1):121-133. Epub 2017 Jun 12.

1School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH UK.

Benthic communities play a major role in organic matter remineralisation and the mediation of many aspects of shelf sea biogeochemistry. Few studies have considered how changes in community structure associated with different levels of physical disturbance affect sediment macronutrients and carbon following the cessation of disturbance. Here, we investigate how faunal activity (sediment particle reworking and bioirrigation) in communities that have survived contrasting levels of bottom fishing affect sediment organic carbon content and macronutrient concentrations ([NH-N], [NO-N], [NO-N], [PO-P], [SiO-Si]). Read More

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http://dx.doi.org/10.1007/s10533-017-0350-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961522PMC

Vulnerability of macronutrients to the concurrent effects of enhanced temperature and atmospheric pCO in representative shelf sea sediment habitats.

Biogeochemistry 2017 9;135(1):89-102. Epub 2017 Jun 9.

1Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton, SO14 3ZH UK.

Fundamental changes in seawater carbonate chemistry and sea surface temperatures associated with the ocean uptake of anthropogenic CO are accelerating, but investigations of the susceptibility of biogeochemical processes to the simultaneous occurrence of multiple components of climate change are uncommon. Here, we quantify how concurrent changes in enhanced temperature and atmospheric pCO, coupled with an associated shift in macrofaunal community structure and behavior (sediment particle reworking and bioirrigation), modify net carbon and nutrient concentrations (NH-N, NO-N, PO-P) in representative shelf sea sediment habitats (mud, sandy-mud, muddy-sand and sand) of the Celtic Sea. We show that net concentrations of organic carbon, nitrogen and phosphate are, irrespective of sediment type, largely unaffected by a simultaneous increase in temperature and atmospheric pCO. Read More

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http://dx.doi.org/10.1007/s10533-017-0340-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961501PMC

Benthic pH gradients across a range of shelf sea sediment types linked to sediment characteristics and seasonal variability.

Biogeochemistry 2017 31;135(1):69-88. Epub 2017 Mar 31.

1Centre for Environment Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT UK.

This study used microelectrodes to record pH profiles in fresh shelf sea sediment cores collected across a range of different sediment types within the Celtic Sea. Spatial and temporal variability was captured during repeated measurements in 2014 and 2015. Concurrently recorded oxygen microelectrode profiles and other sedimentary parameters provide a detailed context for interpretation of the pH data. Read More

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http://dx.doi.org/10.1007/s10533-017-0323-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961502PMC

Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column.

Biogeochemistry 2017 27;135(1):49-67. Epub 2017 Feb 27.

1Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton, SO14 3ZH UK.

Shelf sediments underlying temperate and oxic waters of the Celtic Sea (NW European Shelf) were found to have shallow oxygen penetrations depths from late spring to late summer (2.2-5.8 mm below seafloor) with the shallowest during/after the spring-bloom (mid-April to mid-May) when the organic carbon content was highest. Read More

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http://dx.doi.org/10.1007/s10533-017-0309-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961528PMC
February 2017

Oxygen dynamics in shelf seas sediments incorporating seasonal variability.

Biogeochemistry 2017 29;135(1):35-47. Epub 2017 Mar 29.

Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, PA37 1QA UK.

Shelf sediments play a vital role in global biogeochemical cycling and are particularly important areas of oxygen consumption and carbon mineralisation. Total benthic oxygen uptake, the sum of diffusive and faunal mediated uptake, is a robust proxy to quantify carbon mineralisation. However, oxygen uptake rates are dynamic, due to the diagenetic processes within the sediment, and can be spatially and temporally variable. Read More

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http://dx.doi.org/10.1007/s10533-017-0326-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961513PMC

An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments.

Biogeochemistry 2017 1;135(1):1-34. Epub 2017 Aug 1.

Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH UK.

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. Read More

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http://dx.doi.org/10.1007/s10533-017-0366-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961521PMC

Biogeochemistry of "pristine" freshwater stream and lake systems in the western Canadian Arctic.

Biogeochemistry 2016 11;130(3):191-213. Epub 2016 Oct 11.

6Environmental Sciences, School of Life Sciences, Heriot-Watt University, Edinburgh, EH14 4AS UK.

Climate change poses a substantial threat to the stability of the Arctic terrestrial carbon (C) pool as warmer air temperatures thaw permafrost and deepen the seasonally-thawed active layer of soils and sediments. Enhanced water flow through this layer may accelerate the transport of C and major cations and anions to streams and lakes. These act as important conduits and reactors for dissolved C within the terrestrial C cycle. Read More

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http://dx.doi.org/10.1007/s10533-016-0252-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175648PMC
October 2016

The C:N:P:S stoichiometry of soil organic matter.

Biogeochemistry 2016 23;130(1):117-131. Epub 2016 Sep 23.

3Swiss Federal Research Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland.

The formation and turnover of soil organic matter (SOM) includes the biogeochemical processing of the macronutrient elements nitrogen (N), phosphorus (P) and sulphur (S), which alters their stoichiometric relationships to carbon (C) and to each other. We sought patterns among soil organic C, N, P and S in data for c. 2000 globally distributed soil samples, covering all soil horizons. Read More

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http://dx.doi.org/10.1007/s10533-016-0247-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175710PMC
September 2016

Forest soil CO efflux models improved by incorporating topographic controls on carbon content and sorption capacity of soils.

Biogeochemistry 2016 19;129(3):307-323. Epub 2016 Aug 19.

Department of Biology, Western University, 1151 Richmond Street, London, ON N6A 5B7 Canada.

Improved models are needed to predict the fate of carbon in forest soils under changing environmental conditions. Within a temperate sugar maple forest, soil CO efflux averaged 3.58 µmol m s but ranged from 0. Read More

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http://dx.doi.org/10.1007/s10533-016-0233-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175660PMC

Contribution of carbonate weathering to the CO efflux from temperate forest soils.

Biogeochemistry 2015;124(1-3):273-290. Epub 2015 Apr 14.

Department of Microbiology and Ecosystem Science, Faculty of Life Sciences, University of Vienna, Vienna, Austria.

Temperate forests provide favorable conditions for carbonate bedrock weathering as the soil CO partial pressure is high and soil water is regularly available. As a result of weathering, abiotic CO can be released and contribute to the soil CO efflux. We used the distinct isotopic signature of the abiotic CO to estimate its contribution to the total soil CO efflux. Read More

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http://dx.doi.org/10.1007/s10533-015-0097-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4512732PMC
April 2015
3 Reads

Spatial extent and historical context of North Sea oxygen depletion in August 2010.

Biogeochemistry 2013 22;113(1):53-68. Epub 2012 Apr 22.

1School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ UK.

Prompted by recent observations of seasonal low dissolved oxygen from two moorings in the North Sea, a hydrographic survey in August 2010 mapped the spatial extent of summer oxygen depletion. Typical near-bed dissolved oxygen saturations in the stratified regions of the North Sea were 75-80 % while the well-mixed regions of the southern North Sea reached 90 %. Two regions of strong thermal stratification, the area between the Dooley and Central North Sea Currents and the area known as the Oyster Grounds, had oxygen saturations as low as 65 and 70 % (200 and 180 μmol dm) respectively. Read More

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http://dx.doi.org/10.1007/s10533-012-9729-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175662PMC

Recovery of ecosystem carbon fluxes and storage from herbivory.

Biogeochemistry 2011;106(3):357-370. Epub 2011 Jan 7.

School of Biological Sciences, University of Aberdeen, Cruickshank Building, St. Machar Drive, Aberdeen, AB24 3UU UK.

The carbon (C) sink strength of arctic tundra is under pressure from increasing populations of arctic breeding geese. In this study we examined how CO and CH fluxes, plant biomass and soil C responded to the removal of vertebrate herbivores in a high arctic wet moss meadow that has been intensively used by barnacle geese () for ca. 20 years. Read More

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http://dx.doi.org/10.1007/s10533-010-9516-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4459552PMC
January 2011
26 Reads
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