Articles | Volume 10, issue 3
https://doi.org/10.5194/bg-10-1243-2013
© Author(s) 2013. 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-10-1243-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
01 Mar 2013
Research article |
| 01 Mar 2013
Occurrence of benthic microbial nitrogen fixation coupled to sulfate reduction in the seasonally hypoxic Eckernförde Bay, Baltic Sea
V. J. Bertics
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1–3, 24148 Kiel, Germany
present address: Harvard University, Biological Laboratories, Room 3085, 16 Divinity Avenue, Cambridge, MA 02138, USA
C. R. Löscher
Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany
I. Salonen
Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany
A. W. Dale
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1–3, 24148 Kiel, Germany
J. Gier
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1–3, 24148 Kiel, Germany
R. A. Schmitz
Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany
T. Treude
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1–3, 24148 Kiel, Germany
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Alexandra N. Loginova, Andrew W. Dale, Frédéric A. C. Le Moigne, Sören Thomsen, Stefan Sommer, David Clemens, Klaus Wallmann, and Anja Engel
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We measured dissolved organic carbon (DOC), nitrogen (DON) and matter (DOM) optical properties in pore waters and near-bottom waters of the eastern tropical South Pacific off Peru. The difference between diffusion-driven and net fluxes of DOC and DON and qualitative changes in DOM optical properties suggested active microbial utilisation of the released DOM at the sediment–water interface. Our results suggest that the sediment release of DOM contributes to microbial processes in the area.
Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
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Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
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Carolin R. Löscher, Wiebke Mohr, Hermann W. Bange, and Donald E. Canfield
Biogeosciences, 17, 851–864, https://doi.org/10.5194/bg-17-851-2020, https://doi.org/10.5194/bg-17-851-2020, 2020
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Tronje P. Kemena, Angela Landolfi, Andreas Oschlies, Klaus Wallmann, and Andrew W. Dale
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Konstantin Stolpovsky, Andrew W. Dale, and Klaus Wallmann
Biogeosciences, 15, 3391–3407, https://doi.org/10.5194/bg-15-3391-2018, https://doi.org/10.5194/bg-15-3391-2018, 2018
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Johanna Maltby, Lea Steinle, Carolin R. Löscher, Hermann W. Bange, Martin A. Fischer, Mark Schmidt, and Tina Treude
Biogeosciences, 15, 137–157, https://doi.org/10.5194/bg-15-137-2018, https://doi.org/10.5194/bg-15-137-2018, 2018
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Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, https://doi.org/10.5194/bg-14-2167-2017, 2017
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High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Lea Steinle, Johanna Maltby, Tina Treude, Annette Kock, Hermann W. Bange, Nadine Engbersen, Jakob Zopfi, Moritz F. Lehmann, and Helge Niemann
Biogeosciences, 14, 1631–1645, https://doi.org/10.5194/bg-14-1631-2017, https://doi.org/10.5194/bg-14-1631-2017, 2017
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Large amounts of methane are produced in anoxic, coastal sediments, from which it can seep into the overlying water column. Aerobic oxidation of methane (MOx) mediated by methanotrophic bacteria is an important sink for methane before its evasion to the atmosphere. In a 2-year seasonal study, we investigated the spatio-temporal variability of MOx in a seasonally hypoxic coastal inlet using radiotracer-based methods. In experiments, we assessed the effect of variable oxygen concentrations on MOx.
Björn Fiedler, Damian S. Grundle, Florian Schütte, Johannes Karstensen, Carolin R. Löscher, Helena Hauss, Hannes Wagner, Alexandra Loginova, Rainer Kiko, Péricles Silva, Toste Tanhua, and Arne Körtzinger
Biogeosciences, 13, 5633–5647, https://doi.org/10.5194/bg-13-5633-2016, https://doi.org/10.5194/bg-13-5633-2016, 2016
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Oxygen-depleted mesoscale features in the open eastern tropical North Atlantic, which are formed in the Mauritanian upwelling region, were discovered recently. This study examines biogeochemical structure and magnitudes of related processes within these isolated water masses. We found very low oxygen concentrations and strongly enhanced acidity at near-surface depth. Oxygen utilization and downward carbon export were found to exceed known values for this ocean region.
Jessica Gier, Stefan Sommer, Carolin R. Löscher, Andrew W. Dale, Ruth A. Schmitz, and Tina Treude
Biogeosciences, 13, 4065–4080, https://doi.org/10.5194/bg-13-4065-2016, https://doi.org/10.5194/bg-13-4065-2016, 2016
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Benthic nitrogen fixation and sulfate reduction were investigated in the Peruvian oxygen minimum zone. The data suggest a coupling of both activities to a large extent, but that also sulfide and organic matter availability are controlling the benthic diazotrophy in this area. The molecular analysis confirms the presence of heterotrophic diazotrophs. This work improves our understanding of N cycling in OMZ sediments and the understanding of N sources in the marine environment.
Carolin R. Löscher, Hermann W. Bange, Ruth A. Schmitz, Cameron M. Callbeck, Anja Engel, Helena Hauss, Torsten Kanzow, Rainer Kiko, Gaute Lavik, Alexandra Loginova, Frank Melzner, Judith Meyer, Sven C. Neulinger, Markus Pahlow, Ulf Riebesell, Harald Schunck, Sören Thomsen, and Hannes Wagner
Biogeosciences, 13, 3585–3606, https://doi.org/10.5194/bg-13-3585-2016, https://doi.org/10.5194/bg-13-3585-2016, 2016
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The ocean loses oxygen due to climate change. Addressing this issue in tropical ocean regions (off Peru and Mauritania), we aimed to understand the effects of oxygen depletion on various aspects of marine biogeochemistry, including primary production and export production, the nitrogen cycle, greenhouse gas production, organic matter fluxes and remineralization, and the role of zooplankton and viruses.
Pei-Chuan Chuang, Megan B. Young, Andrew W. Dale, Laurence G. Miller, Jorge A. Herrera-Silveira, and Adina Paytan
Biogeosciences, 13, 2981–3001, https://doi.org/10.5194/bg-13-2981-2016, https://doi.org/10.5194/bg-13-2981-2016, 2016
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A transport-reaction model was used to simulate porewater methane and sulfate concentrations. Model results and sediment slurry incubation experiments show high methane production rates supported by non-competitive substrates and ample dissolved and labile organic matter as well as methane from deeper sediment through bubbles dissolution and diffusion. The shallow methane production and accumulation depths in these sediments promote high methane fluxes to the water column and atmosphere.
Carolin R. Löscher, Annie Bourbonnais, Julien Dekaezemacker, Chawalit N. Charoenpong, Mark A. Altabet, Hermann W. Bange, Rena Czeschel, Chris Hoffmann, and Ruth Schmitz
Biogeosciences, 13, 2889–2899, https://doi.org/10.5194/bg-13-2889-2016, https://doi.org/10.5194/bg-13-2889-2016, 2016
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The ocean is full of eddies and they play a key role for ocean biogeochemistry. In order to understand dinitrogen (N2) fixation, one major control of oceanic primary production, we investigated three eddies in the eastern tropical South Pacific off Peru. We conducted the first detailed survey and found increased N2 fixation in the oxygen-depleted cores of anticyclonic mode water eddies. Taken together, we could – for the first time – show that eddies play an important role in N2 fixation off Peru.
Helena Hauss, Svenja Christiansen, Florian Schütte, Rainer Kiko, Miryam Edvam Lima, Elizandro Rodrigues, Johannes Karstensen, Carolin R. Löscher, Arne Körtzinger, and Björn Fiedler
Biogeosciences, 13, 1977–1989, https://doi.org/10.5194/bg-13-1977-2016, https://doi.org/10.5194/bg-13-1977-2016, 2016
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In a low-oxygen eddy in the tropical Atlantic, total zooplankton biomass was increased. Larger plankton avoided the oxygen minimum zone (OMZ, < 20 µmol O2 kg−1). We identified four strategies by different plankton groups: (i) shallow OMZ avoidance and compression at surface, (ii) migration to shallow OMZ core during daytime, migration to surface at nighttime, (iii) residing in shallow OMZ day and night and (iv) migration through the shallow OMZ from oxygenated depths to surface and back.
Ulrike Lomnitz, Stefan Sommer, Andrew W. Dale, Carolin R. Löscher, Anna Noffke, Klaus Wallmann, and Christian Hensen
Biogeosciences, 13, 1367–1386, https://doi.org/10.5194/bg-13-1367-2016, https://doi.org/10.5194/bg-13-1367-2016, 2016
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The study presents a P budget including the P input from the water column, the P burial in the sediments, as well as the P release from the sediments. We found that the P input could not maintain the P release rates. Consideration of other P sources, e.g., terrigenous P and P released from the dissolution of Fe oxyhydroxides, showed that none of these can account for the missing P. Thus, it is likely that abundant sulfide-oxidizing bacteria release the missing P during our measurement period.
Damian L. Arévalo-Martínez, Annette Kock, Carolin R. Löscher, Ruth A. Schmitz, Lothar Stramma, and Hermann W. Bange
Biogeosciences, 13, 1105–1118, https://doi.org/10.5194/bg-13-1105-2016, https://doi.org/10.5194/bg-13-1105-2016, 2016
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We present the first measurements of N2O across three mesoscale eddies in the eastern tropical South Pacific. Eddie's vertical structure, offshore transport, properties during its formation and near-surface primary production determined the N2O distribution. Substantial depletion of N2O within the core of anticyclonic eddies suggests that although these are transient features, N-loss processes within their centres can lead to an enhanced N2O sink which is not accounted for in marine N2O budgets.
A. Kock, D. L. Arévalo-Martínez, C. R. Löscher, and H. W. Bange
Biogeosciences, 13, 827–840, https://doi.org/10.5194/bg-13-827-2016, https://doi.org/10.5194/bg-13-827-2016, 2016
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We measured the nitrous oxide (N2O) distribution in the water column in the oxygen minimum zone off Peru, an area with extremely high N2O emissions. Our data show very variable and often very high N2O concentrations in the water column at the coast, which lead to high N2O emissions when these waters are brought to the surface. The very high N2O production off Peru may be caused by high nutrient turnover rates together with rapid changes in the oxygen concentrations.
J. Meyer, C. R. Löscher, S. C. Neulinger, A. F. Reichel, A. Loginova, C. Borchard, R. A. Schmitz, H. Hauss, R. Kiko, and U. Riebesell
Biogeosciences, 13, 781–794, https://doi.org/10.5194/bg-13-781-2016, https://doi.org/10.5194/bg-13-781-2016, 2016
J. Maltby, S. Sommer, A. W. Dale, and T. Treude
Biogeosciences, 13, 283–299, https://doi.org/10.5194/bg-13-283-2016, https://doi.org/10.5194/bg-13-283-2016, 2016
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The concurrence of methanogenesis and sulfate reduction was investigated in surface sediments (0–25cm b.s.f.) traversing the Peruvian margin. Surface methanogenesis was mainly based on non-competitive substrates to avoid competition with sulfate reducers. Accordingly, surface methanogenesis was mainly controlled by the availability of labile organic matter. The high relevance of surface methanogenesis especially on the shelf indicates its underestimated role within benthic methane budgeting.
C. R. Löscher, M. A. Fischer, S. C. Neulinger, B. Fiedler, M. Philippi, F. Schütte, A. Singh, H. Hauss, J. Karstensen, A. Körtzinger, S. Künzel, and R. A. Schmitz
Biogeosciences, 12, 7467–7482, https://doi.org/10.5194/bg-12-7467-2015, https://doi.org/10.5194/bg-12-7467-2015, 2015
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The waters of the tropical Atlantic Open Ocean usually contain comparably high concentrations of oxygen. Now, it became clear that there are watermasses related to eddies that are nearly anoxic. We surveyed one of those eddies and found a biosphere that largely differed from the usual biosphere present in this area with a specific community responsible for primary production and for degradation processes. Further, we found the very first indication for active nitrogen loss in the open Atlantic.
P. Steeb, S. Krause, P. Linke, C. Hensen, A. W. Dale, M. Nuzzo, and T. Treude
Biogeosciences, 12, 6687–6706, https://doi.org/10.5194/bg-12-6687-2015, https://doi.org/10.5194/bg-12-6687-2015, 2015
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We combined field, laboratory (sediment-flow-through system) and numerical modeling work to investigate cold seep sediments at Quespos Slide, offshore of Costa Rica. The results demonstrated the efficiency of the benthic methane filter and provided an estimate for its response time (ca. 170 days) to changes in fluid fluxes.
A. W. Dale, S. Sommer, U. Lomnitz, I. Montes, T. Treude, V. Liebetrau, J. Gier, C. Hensen, M. Dengler, K. Stolpovsky, L. D. Bryant, and K. Wallmann
Biogeosciences, 12, 1537–1559, https://doi.org/10.5194/bg-12-1537-2015, https://doi.org/10.5194/bg-12-1537-2015, 2015
J. Friedrich, F. Janssen, D. Aleynik, H. W. Bange, N. Boltacheva, M. N. Çagatay, A. W. Dale, G. Etiope, Z. Erdem, M. Geraga, A. Gilli, M. T. Gomoiu, P. O. J. Hall, D. Hansson, Y. He, M. Holtappels, M. K. Kirf, M. Kononets, S. Konovalov, A. Lichtschlag, D. M. Livingstone, G. Marinaro, S. Mazlumyan, S. Naeher, R. P. North, G. Papatheodorou, O. Pfannkuche, R. Prien, G. Rehder, C. J. Schubert, T. Soltwedel, S. Sommer, H. Stahl, E. V. Stanev, A. Teaca, A. Tengberg, C. Waldmann, B. Wehrli, and F. Wenzhöfer
Biogeosciences, 11, 1215–1259, https://doi.org/10.5194/bg-11-1215-2014, https://doi.org/10.5194/bg-11-1215-2014, 2014
S. Krause, P. Steeb, C. Hensen, V. Liebetrau, A. W. Dale, M. Nuzzo, and T. Treude
Biogeosciences, 11, 507–523, https://doi.org/10.5194/bg-11-507-2014, https://doi.org/10.5194/bg-11-507-2014, 2014
A. W. Dale, V. J. Bertics, T. Treude, S. Sommer, and K. Wallmann
Biogeosciences, 10, 629–651, https://doi.org/10.5194/bg-10-629-2013, https://doi.org/10.5194/bg-10-629-2013, 2013
Related subject area
Biogeochemistry: Sediment
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
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment
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
Carbonate chemistry in sediment porewaters of the Rhône River delta driven by early diagenesis (northwestern Mediterranean)
Anaerobic oxidation of methane alters sediment records of sulfur, iron and phosphorus in the Black Sea
Moderate topsoil erosion rates constrain the magnitude of the erosion-induced carbon sink and agricultural productivity losses on the Chinese Loess Plateau
Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico
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.
Volker Brüchert, Lisa Bröder, Joanna E. Sawicka, Tommaso Tesi, Samantha P. Joye, Xiaole Sun, Igor P. Semiletov, and Vladimir A. Samarkin
Biogeosciences, 15, 471–490, https://doi.org/10.5194/bg-15-471-2018, https://doi.org/10.5194/bg-15-471-2018, 2018
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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.
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.
Jens Rassmann, Bruno Lansard, Lara Pozzato, and Christophe Rabouille
Biogeosciences, 13, 5379–5394, https://doi.org/10.5194/bg-13-5379-2016, https://doi.org/10.5194/bg-13-5379-2016, 2016
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In situ O2 and pH measurements as well as determination of porewater concentrations of dissolved inorganic carbon, total alkalinity, sulfate and calcium have been measured in the sediments of the Rhône prodelta. Biogeochemical activity decreased with distance from the river mouth. Oxic processes decreased the carbonate saturation state (Ω) by lowering pH, whereas anaerobic organic matter degradation, dominated by sulfate reduction, was accompanied by increasing Ω and carbonate precipitation.
Matthias Egger, Peter Kraal, Tom Jilbert, Fatimah Sulu-Gambari, Célia J. Sapart, Thomas Röckmann, and Caroline P. Slomp
Biogeosciences, 13, 5333–5355, https://doi.org/10.5194/bg-13-5333-2016, https://doi.org/10.5194/bg-13-5333-2016, 2016
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By combining detailed geochemical analyses with diagenetic modeling, we provide new insights into how methane dynamics may strongly overprint burial records of iron, sulfur and phosphorus in marine systems subject to changes in organic matter loading or water column salinity. A better understanding of these processes will improve our ability to read ancient sediment records and thus to predict the potential consequences of global warming and human-enhanced inputs of nutrients to the ocean.
Jianlin Zhao, Kristof Van Oost, Longqian Chen, and Gerard Govers
Biogeosciences, 13, 4735–4750, https://doi.org/10.5194/bg-13-4735-2016, https://doi.org/10.5194/bg-13-4735-2016, 2016
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We used a novel approach to reassess erosion rates on the CLP. We found that both current average topsoil erosion rates and the maximum magnitude of the erosion-induced carbon sink are overestimated on the CLP. Although average topsoil losses on the CLP are still high, a major increase in agricultural productivity occurred since 1980. Hence, erosion is currently not a direct threat to agricultural productivity on the CLP but the long-term effects of erosion on soil quality remain important.
Heiko Sahling, Christian Borowski, Elva Escobar-Briones, Adriana Gaytán-Caballero, Chieh-Wei Hsu, Markus Loher, Ian MacDonald, Yann Marcon, Thomas Pape, Miriam Römer, Maxim Rubin-Blum, Florence Schubotz, Daniel Smrzka, Gunter Wegener, and Gerhard Bohrmann
Biogeosciences, 13, 4491–4512, https://doi.org/10.5194/bg-13-4491-2016, https://doi.org/10.5194/bg-13-4491-2016, 2016
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We were excited about nature’s diversity when we discovered spectacular flows of heavy oil at the seafloor with the remotely operated vehicle QUEST 4000 m in Campeche Bay, southern Gulf of Mexico. Vigorous methane gas bubble emissions lead to massive gas hydrate deposits at water depth as deep as 3420 m. The hydrates formed metre-sized mounds at the seafloor that were densely overgrown by vestimentiferan tubeworms and other seep-typical organisms.
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