Articles | Volume 15, issue 2
https://doi.org/10.5194/bg-15-471-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Special issue:
https://doi.org/10.5194/bg-15-471-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
25 Jan 2018
Research article |
| 25 Jan 2018
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment
Volker Brüchert
CORRESPONDING AUTHOR
Department of Geological Sciences, Stockholm University, Stockholm,
Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm,
Sweden
Lisa Bröder
Department of Environmental Sciences and Analytical Chemistry,
Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm,
Sweden
Joanna E. Sawicka
Department of Geological Sciences, Stockholm University, Stockholm,
Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm,
Sweden
Tommaso Tesi
Department of Environmental Sciences and Analytical Chemistry,
Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm,
Sweden
Institute of Marine Sciences, National Research Council, Bologna,
Italy
Samantha P. Joye
Department of Marine Sciences, University of Georgia, Athens, USA
Xiaole Sun
Baltic Sea Centre, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm,
Sweden
Igor P. Semiletov
International Arctic Research Center, University Alaska Fairbanks,
Fairbanks, USA
Pacific Oceanological Institute, Russian Academy of Sciences,
Vladivostok, Russia
Tomsk National Research Polytechnical University, Tomsk, Russia
Vladimir A. Samarkin
Department of Marine Sciences, University of Georgia, Athens, USA
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Recent Arctic studies suggest that sea-ice decline and permafrost thawing will affect the phytoplankton in the Arctic Ocean. However, in what way the plankton composition will change as the warming proceeds remains elusive. Here we show that the carbon composition of plankton might change as a function of the enhanced terrestrial organic carbon supply and progressive sea-ice thawing.
Thomas M. Cronin, Matt O'Regan, Christof Pearce, Laura Gemery, Michael Toomey, Igor Semiletov, and Martin Jakobsson
Clim. Past, 13, 1097–1110, https://doi.org/10.5194/cp-13-1097-2017, https://doi.org/10.5194/cp-13-1097-2017, 2017
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Jorien E. Vonk, Tommaso Tesi, Lisa Bröder, Henry Holmstrand, Gustaf Hugelius, August Andersson, Oleg Dudarev, Igor Semiletov, and Örjan Gustafsson
The Cryosphere, 11, 1879–1895, https://doi.org/10.5194/tc-11-1879-2017, https://doi.org/10.5194/tc-11-1879-2017, 2017
Martin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Göran Björk, Helen Coxall, Agatha de Boer, Larry A. Mayer, Carl-Magnus Mörth, Johan Nilsson, Jayne E. Rattray, Christian Stranne, Igor Semiletov, and Matt O'Regan
Clim. Past, 13, 991–1005, https://doi.org/10.5194/cp-13-991-2017, https://doi.org/10.5194/cp-13-991-2017, 2017
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The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.
Ira Leifer, Denis Chernykh, Natalia Shakhova, and Igor Semiletov
The Cryosphere, 11, 1333–1350, https://doi.org/10.5194/tc-11-1333-2017, https://doi.org/10.5194/tc-11-1333-2017, 2017
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Célia J. Sapart, Natalia Shakhova, Igor Semiletov, Joachim Jansen, Sönke Szidat, Denis Kosmach, Oleg Dudarev, Carina van der Veen, Matthias Egger, Valentine Sergienko, Anatoly Salyuk, Vladimir Tumskoy, Jean-Louis Tison, and Thomas Röckmann
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Leif G. Anderson, Göran Björk, Ola Holby, Sara Jutterström, Carl Magnus Mörth, Matt O'Regan, Christof Pearce, Igor Semiletov, Christian Stranne, Tim Stöven, Toste Tanhua, Adam Ulfsbo, and Martin Jakobsson
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We use data collected in 2014 to show that the outflow of nutrient-rich water occurs much further to the west than has been reported in the past. We suggest that this is due to much less summer sea-ice coverage in the northwestern East Siberian Sea than in the past decades. Further, our data support a more complicated flow pattern in the region where the Mendeleev Ridge reaches the shelf compared to the general cyclonic circulation within the individual basins as suggested historically.
Christof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, and Martin Jakobsson
Clim. Past, 13, 303–316, https://doi.org/10.5194/cp-13-303-2017, https://doi.org/10.5194/cp-13-303-2017, 2017
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The eruption of the Alaskan Aniakchak volcano of 3.6 thousand years ago was one of the largest Holocene eruptions worldwide. The resulting ash is found in several Alaskan sites and as far as Newfoundland and Greenland. In this study, we found ash from the Aniakchak eruption in a marine sediment core from the western Chukchi Sea in the Arctic Ocean. Combined with radiocarbon dates on mollusks, the volcanic age marker is used to calculate the marine radiocarbon reservoir age at that time.
Leif G. Anderson, Jörgen Ek, Ylva Ericson, Christoph Humborg, Igor Semiletov, Marcus Sundbom, and Adam Ulfsbo
Biogeosciences, 14, 1811–1823, https://doi.org/10.5194/bg-14-1811-2017, https://doi.org/10.5194/bg-14-1811-2017, 2017
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Waters with very high pCO2, nutrients and low oxygen concentrations were observed along the continental margin of the East Siberian Sea and well out into the deep Makarov and Canada basins during the SWERUS-C3 expedition in 2014. This water had a low saturation state with respect to calcium carbonate, down to less than 0.8 for calcite and 0.5 for aragonite, and is traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean in the western Fram Strait.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
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In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
Joanna E. Sawicka and Volker Brüchert
Biogeosciences, 14, 325–339, https://doi.org/10.5194/bg-14-325-2017, https://doi.org/10.5194/bg-14-325-2017, 2017
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The biogeochemistry of methane was studied in high-latitude fjord-type estuarine sediment in the Baltic Sea from April 2012 to April 2013. A large variability in methane-producing and methane-oxidizing processes was observed over the year. Oxygen was the most important regulator for the methane flux. In addition to eutrophication effects, free gas movement is suggested as a factor controlling methane concentrations.
Stefano Bonaglia, Astrid Hylén, Jayne E. Rattray, Mikhail Y. Kononets, Nils Ekeroth, Per Roos, Bo Thamdrup, Volker Brüchert, and Per O. J. Hall
Biogeosciences, 14, 285–300, https://doi.org/10.5194/bg-14-285-2017, https://doi.org/10.5194/bg-14-285-2017, 2017
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Understanding nitrogen (N) cycling mechanisms in the ocean is crucial for improving ecosystem management. Here we study N processes by in situ lander and isotope tracer techniques in – so far overlooked – sediments with low organic loads. Denitrification and anammox are the main N transformation processes. However, we demonstrate high contribution of dissimilatory nitrate reduction to ammonium, which recycles a major portion of fixed N to the water column and sustains primary production.
Joan A. Salvadó, Tommaso Tesi, Marcus Sundbom, Emma Karlsson, Martin Kruså, Igor P. Semiletov, Elena Panova, and Örjan Gustafsson
Biogeosciences, 13, 6121–6138, https://doi.org/10.5194/bg-13-6121-2016, https://doi.org/10.5194/bg-13-6121-2016, 2016
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Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. We assessed its fate and composition in different marine pools with a suite of biomarkers. The dissolved organic carbon is transporting off-shelf “young” and fresh vascular plant material, while sedimentary and near-bottom particulate organic carbon preferentially carries old organic carbon released from thawing permafrost.
Robert B. Sparkes, Ayça Doğrul Selver, Örjan Gustafsson, Igor P. Semiletov, Negar Haghipour, Lukas Wacker, Timothy I. Eglinton, Helen M. Talbot, and Bart E. van Dongen
The Cryosphere, 10, 2485–2500, https://doi.org/10.5194/tc-10-2485-2016, https://doi.org/10.5194/tc-10-2485-2016, 2016
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The permafrost in eastern Siberia contains large amounts of carbon frozen in soils and sediments. Continuing global warming is thawing the permafrost and releasing carbon to the Arctic Ocean. We used pyrolysis-GCMS, a chemical fingerprinting technique, to study the types of carbon being deposited on the continental shelf. We found large amounts of permafrost-sourced carbon being deposited up to 200 km offshore.
Lisa Bröder, Tommaso Tesi, Joan A. Salvadó, Igor P. Semiletov, Oleg V. Dudarev, and Örjan Gustafsson
Biogeosciences, 13, 5003–5019, https://doi.org/10.5194/bg-13-5003-2016, https://doi.org/10.5194/bg-13-5003-2016, 2016
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Thawing permafrost may release large amounts of terrestrial organic carbon (TerrOC) to the Arctic Ocean. We assessed its fate in the marine environment with a suite of biomarkers. Across the Laptev Sea their concentrations in surface sediments decreased significantly and showed a trend to qualitatively more degraded TerrOC with increasing water depth. We infer that the degree of degradation of TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport.
Juliane Bischoff, Robert B. Sparkes, Ayça Doğrul Selver, Robert G. M. Spencer, Örjan Gustafsson, Igor P. Semiletov, Oleg V. Dudarev, Dirk Wagner, Elizaveta Rivkina, Bart E. van Dongen, and Helen M. Talbot
Biogeosciences, 13, 4899–4914, https://doi.org/10.5194/bg-13-4899-2016, https://doi.org/10.5194/bg-13-4899-2016, 2016
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The Arctic contains a large pool of carbon that is vulnerable to warming and can be released by rivers and coastal erosion. We study microbial lipids (BHPs) in permafrost and shelf sediments to trace the source, transport and fate of this carbon. BHPs in permafrost deposits are released to the shelf by rivers and coastal erosion, in contrast to other microbial lipids (GDGTs) that are transported by rivers. Several further analyses are needed to understand the complex East Siberian Shelf system.
X. Feng, Ö. Gustafsson, R. M. Holmes, J. E. Vonk, B. E. van Dongen, I. P. Semiletov, O. V. Dudarev, M. B. Yunker, R. W. Macdonald, D. B. Montluçon, and T. I. Eglinton
Biogeosciences, 12, 4841–4860, https://doi.org/10.5194/bg-12-4841-2015, https://doi.org/10.5194/bg-12-4841-2015, 2015
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Currently very few studies have examined the distribution and fate of hydrolyzable organic carbon (OC) in Arctic sediments, whose fate remains unclear in the context of climate change. Our study focuses on the source, distribution and fate of hydrolyzable OC as compared with plant wax lipids and lignin phenols in the sedimentary particles of nine Arctic and sub-Arctic rivers. This multi-molecular approach allows for a comprehensive investigation of terrestrial OC transfer via Arctic rivers.
R. B. Sparkes, A. Doğrul Selver, J. Bischoff, H. M. Talbot, Ö. Gustafsson, I. P. Semiletov, O. V. Dudarev, and B. E. van Dongen
Biogeosciences, 12, 3753–3768, https://doi.org/10.5194/bg-12-3753-2015, https://doi.org/10.5194/bg-12-3753-2015, 2015
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Siberian permafrost contains large amounts of organic carbon that may be released by climate warming. We collected and analysed samples from the East Siberian Sea, using GDGT biomarkers to trace the sourcing and deposition of organic carbon across the shelf. We show that branched GDGTs may be used to trace river erosion. Results from modelling show that organic carbon on the shelf is a complex process involving river-derived and coastal-derived material as well as marine carbon production.
I. P. Semiletov, N. E. Shakhova, I. I. Pipko, S. P. Pugach, A. N. Charkin, O. V. Dudarev, D. A. Kosmach, and S. Nishino
Biogeosciences, 10, 5977–5996, https://doi.org/10.5194/bg-10-5977-2013, https://doi.org/10.5194/bg-10-5977-2013, 2013
Related subject area
Biogeochemistry: Sediment
Reviews and syntheses: Tufa microbialites on rocky coasts – towards an integrated terminology
Seafloor sediment characterization improves estimates of organic carbon standing stocks: an example from the Eastern Shore Islands, Nova Scotia, Canada
How is particulate organic carbon transported through the river-fed submarine Congo Canyon to the deep sea?
The fate of fixed nitrogen in Santa Barbara Basin sediments during seasonal anoxia
Unexpected scarcity of ANME Archaea in hydrocarbon seeps within Monterey Bay
Distinct oxygenation modes of the Gulf of Oman over the past 43 000 years – a multi-proxy approach
Potential impacts of cable bacteria activity on hard-shelled benthic foraminifera: implications for their interpretation as bioindicators or paleoproxies
Evidence of cryptic methane cycling and non-methanogenic methylamine consumption in the sulfate-reducing zone of sediment in the Santa Barbara Basin, California
Assessing global-scale organic matter reactivity patterns in marine sediments using a lognormal reactive continuum model
Deposit-feeding of Nonionellina labradorica (foraminifera) from an Arctic methane seep site and possible association with a methanotroph
Benthic silicon cycling in the Arctic Barents Sea: a reaction–transport model study
Long-term incubations provide insight into the mechanisms of anaerobic oxidation of methane in methanogenic lake sediments
Ideas and perspectives: Sea-level change, anaerobic methane oxidation, and the glacial–interglacial phosphorus cycle
Estimation of the natural background of phosphate in a lowland river using tidal marsh sediment cores
Geochemical consequences of oxygen diffusion from the oceanic crust into overlying sediments and its significance for biogeochemical cycles based on sediments of the northeast Pacific
Carbon sources of benthic fauna in temperate lakes across multiple trophic states
Deep-water inflow event increases sedimentary phosphorus release on a multi-year scale
Bioturbation has a limited effect on phosphorus burial in salt marsh sediments
Biogeochemical impact of cable bacteria on coastal Black Sea sediment
Organic carbon characteristics in ice-rich permafrost in alas and Yedoma deposits, central Yakutia, Siberia
The control of hydrogen sulfide on benthic iron and cadmium fluxes in the oxygen minimum zone off Peru
Quantity and distribution of methane entrapped in sediments of calcareous, Alpine glacier forefields
Assessing the potential for non-turbulent methane escape from the East Siberian Arctic Shelf
Vertical transport of sediment-associated metals and cyanobacteria by ebullition in a stratified lake
Evidence of changes in sedimentation rate and sediment fabric in a low-oxygen setting: Santa Monica Basin, CA
Authigenic formation of Ca–Mg carbonates in the shallow alkaline Lake Neusiedl, Austria
Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia
Impact of ambient conditions on the Si isotope fractionation in marine pore fluids during early diagenesis
Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion–Clipperton Zone, Pacific Ocean
Acetate turnover and methanogenic pathways in Amazonian lake sediments
Benthic alkalinity and dissolved inorganic carbon fluxes in the Rhône River prodelta generated by decoupled aerobic and anaerobic processes
Small-scale heterogeneity of trace metals including rare earth elements and yttrium in deep-sea sediments and porewaters of the Peru Basin, southeastern equatorial Pacific
Organic matter contents and degradation in a highly trawled area during fresh particle inputs (Gulf of Castellammare, southwestern Mediterranean)
Identifying the core bacterial microbiome of hydrocarbon degradation and a shift of dominant methanogenesis pathways in the oil and aqueous phases of petroleum reservoirs of different temperatures from China
Effects of eutrophication on sedimentary organic carbon cycling in five temperate lakes
Evidence for microbial iron reduction in the methanic sediments of the oligotrophic southeastern Mediterranean continental shelf
Fracture-controlled fluid transport supports microbial methane-oxidizing communities at Vestnesa Ridge
Hydrothermal alteration of aragonitic biocarbonates: assessment of micro- and nanostructural dissolution–reprecipitation and constraints of diagenetic overprint from quantitative statistical grain-area analysis
Large variations in iron input to an oligotrophic Baltic Sea estuary: impact on sedimentary phosphorus burial
Vivianite formation in methane-rich deep-sea sediments from the South China Sea
Benthic archaea as potential sources of tetraether membrane lipids in sediments across an oxygen minimum zone
Carbon amendment stimulates benthic nitrogen cycling during the bioremediation of particulate aquaculture waste
Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes
Reviews and syntheses: to the bottom of carbon processing at the seafloor
Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks
Does denitrification occur within porous carbonate sand grains?
Sediment phosphorus speciation and mobility under dynamic redox conditions
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations
Experimental diagenesis: insights into aragonite to calcite transformation of Arctica islandica shells by hydrothermal treatment
Manganese and iron reduction dominate organic carbon oxidation in surface sediments of the deep Ulleung Basin, East Sea
Thomas W. Garner, J. Andrew G. Cooper, Alan M. Smith, Gavin M. Rishworth, and Matt Forbes
Biogeosciences, 21, 4785–4807, https://doi.org/10.5194/bg-21-4785-2024, https://doi.org/10.5194/bg-21-4785-2024, 2024
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There is a diverse and often conflicting suite of terminologies, classifications, and nomenclature applicable to the study of terrestrial carbonate deposits and microbialites (deposits that wholly or primarily accrete as a result of microbial activity). We review existing schemes, identify duplication and redundancy, and present a new integrated approach applicable to tufa microbialites on rock coasts.
Catherine Brenan, Markus Kienast, Vittorio Maselli, Christopher K. Algar, Benjamin Misiuk, and Craig J. Brown
Biogeosciences, 21, 4569–4586, https://doi.org/10.5194/bg-21-4569-2024, https://doi.org/10.5194/bg-21-4569-2024, 2024
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Quantifying how much organic carbon is stored in seafloor sediments is key to assessing how human activities can accelerate the process of carbon storage at the seabed, an important consideration for climate change. This study uses seafloor sediment maps to model organic carbon content. Carbon estimates were 12 times higher when assuming the absence of detailed sediment maps, demonstrating that high-resolution seafloor mapping is critically important for improved estimates of organic carbon.
Sophie Hage, Megan L. Baker, Nathalie Babonneau, Guillaume Soulet, Bernard Dennielou, Ricardo Silva Jacinto, Robert G. Hilton, Valier Galy, François Baudin, Christophe Rabouille, Clément Vic, Sefa Sahin, Sanem Açikalin, and Peter J. Talling
Biogeosciences, 21, 4251–4272, https://doi.org/10.5194/bg-21-4251-2024, https://doi.org/10.5194/bg-21-4251-2024, 2024
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The land-to-ocean flux of particulate organic carbon (POC) is difficult to measure, inhibiting accurate modeling of the global carbon cycle. Here, we quantify the POC flux between one of the largest rivers on Earth (Congo) and the ocean. POC in the form of vegetation and soil is transported by episodic submarine avalanches in a 1000 km long canyon at up to 5 km water depth. The POC flux induced by avalanches is at least 3 times greater than that induced by the background flow related to tides.
Xuefeng Peng, David J. Yousavich, Annie Bourbonnais, Frank Wenzhöfer, Felix Janssen, Tina Treude, and David L. Valentine
Biogeosciences, 21, 3041–3052, https://doi.org/10.5194/bg-21-3041-2024, https://doi.org/10.5194/bg-21-3041-2024, 2024
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Biologically available (fixed) nitrogen (N) is a limiting nutrient for life in the ocean. Under low-oxygen conditions, fixed N is either removed via denitrification or retained via dissimilatory nitrate reduction to ammonia (DNRA). Using in situ incubations in the Santa Barbara Basin, which undergoes seasonal anoxia, we found that benthic denitrification was the dominant nitrate reduction process, while nitrate availability and organic carbon content control the relative importance of DNRA.
Amanda Clare Semler and Anne Elizabeth Dekas
EGUsphere, https://doi.org/10.5194/egusphere-2024-1377, https://doi.org/10.5194/egusphere-2024-1377, 2024
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Marine hydrocarbon seeps typically host subsurface microorganisms capable of degrading methane before it is emitted to the water column. Here we describe a seep in Monterey Bay which virtually lacks known methanotrophs and where biological consumption of methane at depth is undetected. Our findings suggest that some seeps are missing this critical biofilter and that seeps may be a more significant source of methane to the water column than previously realized.
Nicole Burdanowitz, Gerhard Schmiedl, Birgit Gaye, Philipp M. Munz, and Hartmut Schulz
Biogeosciences, 21, 1477–1499, https://doi.org/10.5194/bg-21-1477-2024, https://doi.org/10.5194/bg-21-1477-2024, 2024
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We analyse benthic foraminifera, nitrogen isotopes and lipids in a sediment core from the Gulf of Oman to investigate how the oxygen minimum zone (OMZ) and bottom water (BW) oxygenation have reacted to climatic changes since 43 ka. The OMZ and BW deoxygenation was strong during the Holocene, but the OMZ was well ventilated during the LGM period. We found an unstable mode of oscillating oxygenation states, from moderately oxygenated in cold stadials to deoxygenated in warm interstadials in MIS 3.
Maxime Daviray, Emmanuelle Geslin, Nils Risgaard-Petersen, Vincent V. Scholz, Marie Fouet, and Edouard Metzger
Biogeosciences, 21, 911–928, https://doi.org/10.5194/bg-21-911-2024, https://doi.org/10.5194/bg-21-911-2024, 2024
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Coastal marine sediments are subject to major acidification processes because of climate change and human activities, but these processes can also result from biotic activity. We studied the sediment acidifcation effect on benthic calcareous foraminifera in intertidal mudflats. The strong pH decrease in sediments probably caused by cable bacteria led to calcareous test dissolution of living and dead foraminifera, threatening the test preservation and their robustness as environmental proxies.
Sebastian J. E. Krause, Jiarui Liu, David J. Yousavich, DeMarcus Robinson, David W. Hoyt, Qianhui Qin, Frank Wenzhöfer, Felix Janssen, David L. Valentine, and Tina Treude
Biogeosciences, 20, 4377–4390, https://doi.org/10.5194/bg-20-4377-2023, https://doi.org/10.5194/bg-20-4377-2023, 2023
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Methane is a potent greenhouse gas, and hence it is important to understand its sources and sinks in the environment. Here we present new data from organic-rich surface sediments below an oxygen minimum zone off the coast of California (Santa Barbara Basin) demonstrating the simultaneous microbial production and consumption of methane, which appears to be an important process preventing the build-up of methane in these sediments and the emission into the water column and atmosphere.
Sinan Xu, Bo Liu, Sandra Arndt, Sabine Kasten, and Zijun Wu
Biogeosciences, 20, 2251–2263, https://doi.org/10.5194/bg-20-2251-2023, https://doi.org/10.5194/bg-20-2251-2023, 2023
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We use a reactive continuum model based on a lognormal distribution (l-RCM) to inversely determine model parameters μ and σ at 123 sites across the global ocean. Our results show organic matter (OM) reactivity is more than 3 orders of magnitude higher in shelf than in abyssal regions. In addition, OM reactivity is higher than predicted in some specific regions, yet the l-RCM can still capture OM reactivity features in these regions.
Christiane Schmidt, Emmanuelle Geslin, Joan M. Bernhard, Charlotte LeKieffre, Mette Marianne Svenning, Helene Roberge, Magali Schweizer, and Giuliana Panieri
Biogeosciences, 19, 3897–3909, https://doi.org/10.5194/bg-19-3897-2022, https://doi.org/10.5194/bg-19-3897-2022, 2022
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This study is the first to show non-selective deposit feeding in the foraminifera Nonionella labradorica and the possible uptake of methanotrophic bacteria. We carried out a feeding experiment with a marine methanotroph to examine the ultrastructure of the cell and degradation vacuoles using transmission electron microscopy (TEM). The results revealed three putative methanotrophs at the outside of the cell/test, which could be taken up via non-targeted grazing in seeps or our experiment.
James P. J. Ward, Katharine R. Hendry, Sandra Arndt, Johan C. Faust, Felipe S. Freitas, Sian F. Henley, Jeffrey W. Krause, Christian März, Allyson C. Tessin, and Ruth L. Airs
Biogeosciences, 19, 3445–3467, https://doi.org/10.5194/bg-19-3445-2022, https://doi.org/10.5194/bg-19-3445-2022, 2022
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The seafloor plays an important role in the cycling of silicon (Si), a key nutrient that promotes marine primary productivity. In our model study, we disentangle major controls on the seafloor Si cycle to better anticipate the impacts of continued warming and sea ice melt in the Barents Sea. We uncover a coupling of the iron redox and Si cycles, dissolution of lithogenic silicates, and authigenic clay formation, comprising a Si sink that could have implications for the Arctic Ocean Si budget.
Hanni Vigderovich, Werner Eckert, Michal Elul, Maxim Rubin-Blum, Marcus Elvert, and Orit Sivan
Biogeosciences, 19, 2313–2331, https://doi.org/10.5194/bg-19-2313-2022, https://doi.org/10.5194/bg-19-2313-2022, 2022
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Anaerobic oxidation of methane (AOM) is one of the major processes limiting the release of the greenhouse gas methane from natural environments. Here we show that significant AOM exists in the methane zone of lake sediments in natural conditions and even after long-term (ca. 18 months) anaerobic slurry incubations with two stages. Methanogens were most likely responsible for oxidizing the methane, and humic substances and iron oxides are likely electron acceptors to support this oxidation.
Bjorn Sundby, Pierre Anschutz, Pascal Lecroart, and Alfonso Mucci
Biogeosciences, 19, 1421–1434, https://doi.org/10.5194/bg-19-1421-2022, https://doi.org/10.5194/bg-19-1421-2022, 2022
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A glacial–interglacial methane-fuelled redistribution of reactive phosphorus between the oceanic and sedimentary phosphorus reservoirs can occur in the ocean when falling sea level lowers the pressure on the seafloor, destabilizes methane hydrates, and triggers the dissolution of P-bearing iron oxides. The mass of phosphate potentially mobilizable from the sediment is similar to the size of the current oceanic reservoir. Hence, this process may play a major role in the marine phosphorus cycle.
Florian Lauryssen, Philippe Crombé, Tom Maris, Elliot Van Maldegem, Marijn Van de Broek, Stijn Temmerman, and Erik Smolders
Biogeosciences, 19, 763–776, https://doi.org/10.5194/bg-19-763-2022, https://doi.org/10.5194/bg-19-763-2022, 2022
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Surface waters in lowland regions have a poor surface water quality, mainly due to excess nutrients like phosphate. Therefore, we wanted to know the phosphate levels without humans, also called the pre-industrial background. Phosphate binds strongly to sediment particles, suspended in the river water. In this research we used sediments deposited by a river as an archive for surface water phosphate back to 1800 CE. Pre-industrial phosphate levels were estimated at one-third of the modern levels.
Gerard J. M. Versteegh, Andrea Koschinsky, Thomas Kuhn, Inken Preuss, and Sabine Kasten
Biogeosciences, 18, 4965–4984, https://doi.org/10.5194/bg-18-4965-2021, https://doi.org/10.5194/bg-18-4965-2021, 2021
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Oxygen penetrates sediments not only from the ocean bottom waters but also from the basement. The impact of the latter is poorly understood. We show that this basement oxygen has a clear impact on the nitrogen cycle, the redox state, and the distribution of manganese, nickel cobalt and organic matter in the sediments. This is important for (1) global biogeochemical cycles, (2) understanding sedimentary life and (3) the interpretation of the sediment record to reconstruct the past.
Annika Fiskal, Eva Anthamatten, Longhui Deng, Xingguo Han, Lorenzo Lagostina, Anja Michel, Rong Zhu, Nathalie Dubois, Carsten J. Schubert, Stefano M. Bernasconi, and Mark A. Lever
Biogeosciences, 18, 4369–4388, https://doi.org/10.5194/bg-18-4369-2021, https://doi.org/10.5194/bg-18-4369-2021, 2021
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Microbially produced methane can serve as a carbon source for freshwater macrofauna most likely through grazing on methane-oxidizing bacteria. This study investigates the contributions of different carbon sources to macrofaunal biomass. Our data suggest that the average contribution of methane-derived carbon is similar between different fauna but overall remains low. This is further supported by the low abundance of methane-cycling microorganisms.
Astrid Hylén, Sebastiaan J. van de Velde, Mikhail Kononets, Mingyue Luo, Elin Almroth-Rosell, and Per O. J. Hall
Biogeosciences, 18, 2981–3004, https://doi.org/10.5194/bg-18-2981-2021, https://doi.org/10.5194/bg-18-2981-2021, 2021
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Sediments in oxygen-depleted ocean areas release high amounts of phosphorus, feeding algae that consume oxygen upon degradation, leading to further phosphorus release. Oxygenation is thought to trap phosphorus in the sediment and break this feedback. We studied the sediment phosphorus cycle in a previously anoxic area after an inflow of oxic water. Surprisingly, the sediment phosphorus release increased, showing that feedbacks between phosphorus release and oxygen depletion can be hard to break.
Sebastiaan J. van de Velde, Rebecca K. James, Ine Callebaut, Silvia Hidalgo-Martinez, and Filip J. R. Meysman
Biogeosciences, 18, 1451–1461, https://doi.org/10.5194/bg-18-1451-2021, https://doi.org/10.5194/bg-18-1451-2021, 2021
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Some 540 Myr ago, animal life evolved in the ocean. Previous research suggested that when these early animals started inhabiting the seafloor, they retained phosphorus in the seafloor, thereby limiting photosynthesis in the ocean. We studied salt marsh sediments with and without animals and found that their impact on phosphorus retention is limited, which implies that their impact on the global environment might have been less drastic than previously assumed.
Martijn Hermans, Nils Risgaard-Petersen, Filip J. R. Meysman, and Caroline P. Slomp
Biogeosciences, 17, 5919–5938, https://doi.org/10.5194/bg-17-5919-2020, https://doi.org/10.5194/bg-17-5919-2020, 2020
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This paper demonstrates that the recently discovered cable bacteria are capable of using a mineral, known as siderite, as a source for the formation of iron oxides. This work also demonstrates that the activity of cable bacteria can lead to a distinct subsurface layer in the sediment that can be used as a marker for their activity.
Torben Windirsch, Guido Grosse, Mathias Ulrich, Lutz Schirrmeister, Alexander N. Fedorov, Pavel Y. Konstantinov, Matthias Fuchs, Loeka L. Jongejans, Juliane Wolter, Thomas Opel, and Jens Strauss
Biogeosciences, 17, 3797–3814, https://doi.org/10.5194/bg-17-3797-2020, https://doi.org/10.5194/bg-17-3797-2020, 2020
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To extend the knowledge on circumpolar deep permafrost carbon storage, we examined two deep permafrost deposit types (Yedoma and alas) in central Yakutia. We found little but partially undecomposed organic carbon as a result of largely changing sedimentation processes. The carbon stock of the examined Yedoma deposits is about 50 % lower than the general Yedoma domain mean, implying a very hetererogeneous Yedoma composition, while the alas is approximately 80 % below the thermokarst deposit mean.
Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
Biogeosciences, 17, 3685–3704, https://doi.org/10.5194/bg-17-3685-2020, https://doi.org/10.5194/bg-17-3685-2020, 2020
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We compare the cycling of Fe and Cd in sulfidic sediments of the Peruvian oxygen minimum zone. Due to the contrasting solubility of their sulfide minerals, the sedimentary Fe release and Cd burial fluxes covary with spatial and temporal distributions of H2S. Depending on the solubility of their sulfide minerals, sedimentary trace metal fluxes will respond differently to ocean deoxygenation/expansion of H2S concentrations, which may change trace metal stoichiometry of upwelling water masses.
Biqing Zhu, Manuel Kübler, Melanie Ridoli, Daniel Breitenstein, and Martin H. Schroth
Biogeosciences, 17, 3613–3630, https://doi.org/10.5194/bg-17-3613-2020, https://doi.org/10.5194/bg-17-3613-2020, 2020
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We provide evidence that the greenhouse gas methane (CH4) is enclosed in calcareous glacier-forefield sediments across Switzerland. Geochemical analyses confirmed that this ancient CH4 has its origin in the calcareous parent bedrock. Our estimate of the total quantity of CH4 enclosed in sediments across Switzerland indicates a large CH4 mass (~105 t CH4). We produced evidence that CH4 is stable in its enclosed state, but additional experiments are needed to elucidate its long-term fate.
Matteo Puglini, Victor Brovkin, Pierre Regnier, and Sandra Arndt
Biogeosciences, 17, 3247–3275, https://doi.org/10.5194/bg-17-3247-2020, https://doi.org/10.5194/bg-17-3247-2020, 2020
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A reaction-transport model to assess the potential non-turbulent methane flux from the East Siberian Arctic sediments to water columns is applied here. We show that anaerobic oxidation of methane (AOM) is an efficient filter except for high values of sedimentation rate and advective flow, which enable considerable non-turbulent steady-state methane fluxes. Significant transient methane fluxes can also occur during the building-up phase of the AOM-performing biomass microbial community.
Kyle Delwiche, Junyao Gu, Harold Hemond, and Sarah P. Preheim
Biogeosciences, 17, 3135–3147, https://doi.org/10.5194/bg-17-3135-2020, https://doi.org/10.5194/bg-17-3135-2020, 2020
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In this study, we investigate whether bubbles transport sediments containing arsenic and cyanobacteria from the bottom to the top of a polluted lake. We measured arsenic and cyanobacteria from bubble traps in the lake and from an experimental bubble column in the laboratory. We found that bubble transport was not an important source of arsenic in the surface waters but that bubbles could transport enough cyanobacteria to the surface to exacerbate harmful algal blooms.
Nathaniel Kemnitz, William M. Berelson, Douglas E. Hammond, Laura Morine, Maria Figueroa, Timothy W. Lyons, Simon Scharf, Nick Rollins, Elizabeth Petsios, Sydnie Lemieux, and Tina Treude
Biogeosciences, 17, 2381–2396, https://doi.org/10.5194/bg-17-2381-2020, https://doi.org/10.5194/bg-17-2381-2020, 2020
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Our paper shows how sedimentation in a very low oxygen setting provides a unique record of environmental change. We look at the past 250 years through the filter of sediment accumulation via radioisotope dating and other physical and chemical analyses of these sediments. We conclude, remarkably, that there has been very little change in net sediment mass accumulation through the past 100–150 years, yet just prior to 1900 CE, sediments were accumulating at 50 %–70 % of today's rate.
Dario Fussmann, Avril Jean Elisabeth von Hoyningen-Huene, Andreas Reimer, Dominik Schneider, Hana Babková, Robert Peticzka, Andreas Maier, Gernot Arp, Rolf Daniel, and Patrick Meister
Biogeosciences, 17, 2085–2106, https://doi.org/10.5194/bg-17-2085-2020, https://doi.org/10.5194/bg-17-2085-2020, 2020
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Dolomite (CaMg(CO3)2) is supersaturated in many aquatic settings (e.g., seawater) on modern Earth but does not precipitate directly from the fluid, a fact known as the dolomite problem. The widely acknowledged concept of dolomite precipitation involves microbial extracellular polymeric substances (EPSs) and anoxic conditions as important drivers. In contrast, results from Lake Neusiedl support an alternative concept of Ca–Mg carbonate precipitation under aerobic and alkaline conditions.
Aurèle Vuillemin, André Friese, Richard Wirth, Jan A. Schuessler, Anja M. Schleicher, Helga Kemnitz, Andreas Lücke, Kohen W. Bauer, Sulung Nomosatryo, Friedhelm von Blanckenburg, Rachel Simister, Luis G. Ordoñez, Daniel Ariztegui, Cynthia Henny, James M. Russell, Satria Bijaksana, Hendrik Vogel, Sean A. Crowe, Jens Kallmeyer, and the Towuti Drilling Project
Science team
Biogeosciences, 17, 1955–1973, https://doi.org/10.5194/bg-17-1955-2020, https://doi.org/10.5194/bg-17-1955-2020, 2020
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Ferruginous lakes experience restricted primary production due to phosphorus trapping by ferric iron oxides under oxic conditions. We report the presence of large crystals of vivianite, a ferrous iron phosphate, in sediments from Lake Towuti, Indonesia. We address processes of P retention linked to diagenesis of iron phases. Vivianite crystals had light Fe2+ isotope signatures and contained mineral inclusions consistent with antecedent processes of microbial sulfate and iron reduction.
Sonja Geilert, Patricia Grasse, Kristin Doering, Klaus Wallmann, Claudia Ehlert, Florian Scholz, Martin Frank, Mark Schmidt, and Christian Hensen
Biogeosciences, 17, 1745–1763, https://doi.org/10.5194/bg-17-1745-2020, https://doi.org/10.5194/bg-17-1745-2020, 2020
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Marine silicate weathering is a key process of the marine silica cycle; however, its controlling processes are not well understood. In the Guaymas Basin, silicate weathering has been studied under markedly differing ambient conditions. Environmental settings like redox conditions or terrigenous input of reactive silicates appear to be major factors controlling marine silicate weathering. These factors need to be taken into account in future oceanic mass balances of Si and in modeling studies.
Jessica B. Volz, Laura Haffert, Matthias Haeckel, Andrea Koschinsky, and Sabine Kasten
Biogeosciences, 17, 1113–1131, https://doi.org/10.5194/bg-17-1113-2020, https://doi.org/10.5194/bg-17-1113-2020, 2020
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Potential future deep-sea mining of polymetallic nodules at the seafloor is expected to severely harm the marine environment. However, the consequences on deep-sea ecosystems are still poorly understood. This study on surface sediments from man-made disturbance tracks in the Pacific Ocean shows that due to the removal of the uppermost sediment layer and thereby the loss of organic matter, the geochemical system in the sediments is disturbed for millennia before reaching a new equilibrium.
Ralf Conrad, Melanie Klose, and Alex Enrich-Prast
Biogeosciences, 17, 1063–1069, https://doi.org/10.5194/bg-17-1063-2020, https://doi.org/10.5194/bg-17-1063-2020, 2020
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Lake sediments release the greenhouse gas CH4. Acetate is an important precursor. Although Amazonian lake sediments all contained acetate-consuming methanogens, measurement of the turnover of labeled acetate showed that some sediments converted acetate not to CH4 plus CO2, as expected, but only to CO2. Our results indicate the operation of acetate-oxidizing microorganisms couples the oxidation process to syntrophic methanogenic partners and/or to the reduction of organic compounds.
Jens Rassmann, Eryn M. Eitel, Bruno Lansard, Cécile Cathalot, Christophe Brandily, Martial Taillefert, and Christophe Rabouille
Biogeosciences, 17, 13–33, https://doi.org/10.5194/bg-17-13-2020, https://doi.org/10.5194/bg-17-13-2020, 2020
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In this paper, we use a large set of measurements made using in situ and lab techniques to elucidate the cause of dissolved inorganic carbon fluxes in sediments from the Rhône delta and its companion compound alkalinity, which carries the absorption capacity of coastal waters with respect to atmospheric CO2. We show that sediment processes (sulfate reduction, FeS precipitation and accumulation) are crucial in generating the alkalinity fluxes observed in this study by in situ incubation chambers.
Sophie A. L. Paul, Matthias Haeckel, Michael Bau, Rajina Bajracharya, and Andrea Koschinsky
Biogeosciences, 16, 4829–4849, https://doi.org/10.5194/bg-16-4829-2019, https://doi.org/10.5194/bg-16-4829-2019, 2019
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We studied the upper 10 m of deep-sea sediments, including pore water, in the Peru Basin to understand small-scale variability of trace metals. Our results show high spatial variability related to topographical variations, which in turn impact organic matter contents, degradation processes, and trace metal cycling. Another interesting finding was the influence of dissolving buried nodules on the surrounding sediment and trace metal cycling.
Sarah Paradis, Antonio Pusceddu, Pere Masqué, Pere Puig, Davide Moccia, Tommaso Russo, and Claudio Lo Iacono
Biogeosciences, 16, 4307–4320, https://doi.org/10.5194/bg-16-4307-2019, https://doi.org/10.5194/bg-16-4307-2019, 2019
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Chronic deep bottom trawling in the Gulf of Castellammare (SW Mediterranean) erodes large volumes of sediment, exposing over-century-old sediment depleted in organic matter. Nevertheless, the arrival of fresh and nutritious sediment recovers superficial organic matter in trawling grounds and leads to high turnover rates, partially and temporarily mitigating the impacts of bottom trawling. However, this deposition is ephemeral and it will be swiftly eroded by the passage of the next trawler.
Zhichao Zhou, Bo Liang, Li-Ying Wang, Jin-Feng Liu, Bo-Zhong Mu, Hojae Shim, and Ji-Dong Gu
Biogeosciences, 16, 4229–4241, https://doi.org/10.5194/bg-16-4229-2019, https://doi.org/10.5194/bg-16-4229-2019, 2019
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This study shows a core bacterial microbiome with a small proportion of shared operational taxonomic units of common sequences among all oil reservoirs. Dominant methanogenesis shifts from the hydrogenotrophic pathway in water phase to the acetoclastic pathway in the oil phase at high temperatures, but the opposite is true at low temperatures. There are also major functional metabolism differences between the two phases for amino acids, hydrocarbons, and carbohydrates.
Annika Fiskal, Longhui Deng, Anja Michel, Philip Eickenbusch, Xingguo Han, Lorenzo Lagostina, Rong Zhu, Michael Sander, Martin H. Schroth, Stefano M. Bernasconi, Nathalie Dubois, and Mark A. Lever
Biogeosciences, 16, 3725–3746, https://doi.org/10.5194/bg-16-3725-2019, https://doi.org/10.5194/bg-16-3725-2019, 2019
Hanni Vigderovich, Lewen Liang, Barak Herut, Fengping Wang, Eyal Wurgaft, Maxim Rubin-Blum, and Orit Sivan
Biogeosciences, 16, 3165–3181, https://doi.org/10.5194/bg-16-3165-2019, https://doi.org/10.5194/bg-16-3165-2019, 2019
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Microbial iron reduction participates in important biogeochemical cycles. In the last decade iron reduction has been observed in many aquatic sediments below its classical zone, in the methane production zone, suggesting a link between the two cycles. Here we present evidence for microbial iron reduction in the methanogenic depth of the oligotrophic SE Mediterranean continental shelf using mainly geochemical and microbial sedimentary profiles and suggest possible mechanisms for this process.
Haoyi Yao, Wei-Li Hong, Giuliana Panieri, Simone Sauer, Marta E. Torres, Moritz F. Lehmann, Friederike Gründger, and Helge Niemann
Biogeosciences, 16, 2221–2232, https://doi.org/10.5194/bg-16-2221-2019, https://doi.org/10.5194/bg-16-2221-2019, 2019
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How methane is transported in the sediment is important for the microbial community living on methane. Here we report an observation of a mini-fracture that facilitates the advective gas transport of methane in the sediment, compared to the diffusive fluid transport without a fracture. We found contrasting bio-geochemical signals in these different transport modes. This finding can help to fill the gap in the fracture network system in modulating methane dynamics in surface sediments.
Laura A. Casella, Sixin He, Erika Griesshaber, Lourdes Fernández-Díaz, Martina Greiner, Elizabeth M. Harper, Daniel J. Jackson, Andreas Ziegler, Vasileios Mavromatis, Martin Dietzel, Anton Eisenhauer, Sabino Veintemillas-Verdaguer, Uwe Brand, and Wolfgang W. Schmahl
Biogeosciences, 15, 7451–7484, https://doi.org/10.5194/bg-15-7451-2018, https://doi.org/10.5194/bg-15-7451-2018, 2018
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Biogenic carbonates record past environmental conditions. Fossil shell chemistry and microstructure change as metastable biogenic carbonates are replaced by inorganic calcite. Simulated diagenetic alteration at 175 °C of different shell microstructures showed that (nacreous) shell aragonite and calcite were partially replaced by coarse inorganic calcite crystals due to dissolution–reprecipitation reactions. EBSD maps allowed for qualitative assessment of the degree of diagenetic overprint.
Wytze K. Lenstra, Matthias Egger, Niels A. G. M. van Helmond, Emma Kritzberg, Daniel J. Conley, and Caroline P. Slomp
Biogeosciences, 15, 6979–6996, https://doi.org/10.5194/bg-15-6979-2018, https://doi.org/10.5194/bg-15-6979-2018, 2018
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We show that burial rates of phosphorus (P) in an estuary in the northern Baltic Sea are very high. We demonstrate that at high sedimentation rates, P retention in the sediment is related to the formation of vivianite. With a reactive transport model, we assess the sensitivity of sedimentary vivianite formation. We suggest that enrichments of iron and P in the sediment are linked to periods of enhanced riverine input of Fe, which subsequently strongly enhances P burial in coastal sediments.
Jiarui Liu, Gareth Izon, Jiasheng Wang, Gilad Antler, Zhou Wang, Jie Zhao, and Matthias Egger
Biogeosciences, 15, 6329–6348, https://doi.org/10.5194/bg-15-6329-2018, https://doi.org/10.5194/bg-15-6329-2018, 2018
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Our work provides new insights into the biogeochemical cycling of iron, methane and phosphorus. We found that vivianite, an iron-phosphate mineral, is pervasive in methane-rich sediments, suggesting that iron reduction at depth is coupled to phosphorus and methane cycling on a much greater spatial scale than previously assumed. Acting as an important burial mechanism for iron and phosphorus, vivianite authigenesis may be an under-considered process in both modern and ancient settings alike.
Marc A. Besseling, Ellen C. Hopmans, R. Christine Boschman, Jaap S. Sinninghe Damsté, and Laura Villanueva
Biogeosciences, 15, 4047–4064, https://doi.org/10.5194/bg-15-4047-2018, https://doi.org/10.5194/bg-15-4047-2018, 2018
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Benthic archaea comprise a significant part of the total prokaryotic biomass in marine sediments. Here, we compared the archaeal diversity and intact polar lipid (IPL) composition in both surface and subsurface sediments with different oxygen regimes in the Arabian Sea oxygen minimum zone. The oxygenated sediments were dominated by Thaumarchaeota and IPL-GDGT-0. The anoxic sediment contained highly diverse archaeal communities and high relative abundances of IPL-GDGT-1 to -4.
Georgina Robinson, Thomas MacTavish, Candida Savage, Gary S. Caldwell, Clifford L. W. Jones, Trevor Probyn, Bradley D. Eyre, and Selina M. Stead
Biogeosciences, 15, 1863–1878, https://doi.org/10.5194/bg-15-1863-2018, https://doi.org/10.5194/bg-15-1863-2018, 2018
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This study examined the effect of adding carbon to a sediment-based effluent treatment system to treat nitrogen-rich aquaculture waste. The research was conducted in incubation chambers to measure the exchange of gases and nutrients across the sediment–water interface and examine changes in the sediment microbial community. Adding carbon increased the amount of nitrogen retained in the treatment system, thereby reducing the levels of nitrogen needing to be discharged to the environment.
Daniele Brigolin, Christophe Rabouille, Bruno Bombled, Silvia Colla, Salvatrice Vizzini, Roberto Pastres, and Fabio Pranovi
Biogeosciences, 15, 1347–1366, https://doi.org/10.5194/bg-15-1347-2018, https://doi.org/10.5194/bg-15-1347-2018, 2018
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We present the result of a study carried out in the north-western Adriatic Sea by combining two different types of models with field sampling. A mussel farm was taken as a local source of perturbation to the natural flux of particulate organic carbon to the sediment. Differences in fluxes were primarily associated with mussel physiological conditions. Although restricted, these changes in particulate organic carbon fluxes induced visible effects on sediment biogeochemistry.
Jack J. Middelburg
Biogeosciences, 15, 413–427, https://doi.org/10.5194/bg-15-413-2018, https://doi.org/10.5194/bg-15-413-2018, 2018
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Organic carbon processing at the seafloor is studied by geologists to better understand the sedimentary record, by biogeochemists to quantify burial and respiration, by organic geochemists to elucidate compositional changes, and by ecologists to follow carbon transfers within food webs. These disciplinary approaches have their strengths and weaknesses. This award talk provides a synthesis, highlights the role of animals in sediment carbon processing and presents some new concepts.
Craig Smeaton, William E. N. Austin, Althea L. Davies, Agnes Baltzer, John A. Howe, and John M. Baxter
Biogeosciences, 14, 5663–5674, https://doi.org/10.5194/bg-14-5663-2017, https://doi.org/10.5194/bg-14-5663-2017, 2017
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Fjord sediments are recognised as hotspots for the burial and long-term storage of carbon. In this study, we use the Scottish fjords as a natural laboratory. Using geophysical and geochemical analysis in combination with upscaling techniques, we have generated the first full national sedimentary C inventory for a fjordic system. The results indicate that the Scottish fjords on a like-for-like basis are more effective as C stores than their terrestrial counterparts, including Scottish peatlands.
Perran Louis Miall Cook, Adam John Kessler, and Bradley David Eyre
Biogeosciences, 14, 4061–4069, https://doi.org/10.5194/bg-14-4061-2017, https://doi.org/10.5194/bg-14-4061-2017, 2017
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Nitrogen is the key nutrient that typically limits productivity in coastal waters. One of the key controls on the amount of bioavailable nitrogen is the process of denitrification, which converts nitrate (bioavailable) into nitrogen gas. Previous studies suggest high rates of denitrification may take place within carbonate sediments, and one explanation for this is that this process may take place within the sand grains. Here we show evidence to support this hypothesis.
Chris T. Parsons, Fereidoun Rezanezhad, David W. O'Connell, and Philippe Van Cappellen
Biogeosciences, 14, 3585–3602, https://doi.org/10.5194/bg-14-3585-2017, https://doi.org/10.5194/bg-14-3585-2017, 2017
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Phosphorus (P) has accumulated in sediments due to past human activities. The re-release of this P to water contributes to the growth of harmful algal blooms. Our research improves our mechanistic understanding of how P is partitioned between different chemical forms and between sediment and water under dynamic conditions. We demonstrate that P trapped within iron minerals may be less mobile during anoxic conditions than previously thought due to reversible changes to P forms within sediment.
Clint M. Miller, Gerald R. Dickens, Martin Jakobsson, Carina Johansson, Andrey Koshurnikov, Matt O'Regan, Francesco Muschitiello, Christian Stranne, and Carl-Magnus Mörth
Biogeosciences, 14, 2929–2953, https://doi.org/10.5194/bg-14-2929-2017, https://doi.org/10.5194/bg-14-2929-2017, 2017
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Continental slopes north of the East Siberian Sea are assumed to hold large amounts of methane. We present pore water chemistry from the 2014 SWERUS-C3 expedition. These are among the first results generated from this vast climatically sensitive region, and they imply that abundant methane, including gas hydrates, do not characterize the East Siberian Sea slope or rise. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based assumption.
Laura A. Casella, Erika Griesshaber, Xiaofei Yin, Andreas Ziegler, Vasileios Mavromatis, Dirk Müller, Ann-Christine Ritter, Dorothee Hippler, Elizabeth M. Harper, Martin Dietzel, Adrian Immenhauser, Bernd R. Schöne, Lucia Angiolini, and Wolfgang W. Schmahl
Biogeosciences, 14, 1461–1492, https://doi.org/10.5194/bg-14-1461-2017, https://doi.org/10.5194/bg-14-1461-2017, 2017
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Mollusc shells record past environments. Fossil shell chemistry and microstructure change as metastable biogenic aragonite transforms to stable geogenic calcite. We simulated this alteration of Arctica islandica shells by hydrothermal treatments. Below 175 °C the shell aragonite survived for weeks. At 175 °C the replacement of the original material starts after 4 days and yields submillimetre-sized calcites preserving the macroscopic morphology as well as the original internal micromorphology.
Jung-Ho Hyun, Sung-Han Kim, Jin-Sook Mok, Hyeyoun Cho, Tongsup Lee, Verona Vandieken, and Bo Thamdrup
Biogeosciences, 14, 941–958, https://doi.org/10.5194/bg-14-941-2017, https://doi.org/10.5194/bg-14-941-2017, 2017
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The surface sediments of the Ulleung Basin (UB) in the East Sea are characterized by high organic carbon contents (> 2.5 %, dry wt.) and very high concentrations of Mn oxides (> 200 μmol cm−3) and Fe oxides (up to 100 μmol cm−3). For the first time in deep offshore sediments on the Asian margin with water depth over 2000 m, we report that Mn reduction and Fe reduction were the dominant organic carbon (Corg) oxidation pathways, comprising 45 % and 20 % of total Corg oxidation, respectively.
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Short summary
We determined the aerobic and anaerobic degradation rates of land- and marine-derived organic material in East Siberian shelf sediment. Marine plankton-derived organic carbon was the main source for the oxic dissolved carbon dioxide production, whereas terrestrial organic material significantly contributed to the production of carbon dioxide under anoxic conditions. Our direct degradation rate measurements provide new constraints for the present-day Arctic marine carbon budget.
We determined the aerobic and anaerobic degradation rates of land- and marine-derived organic...
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