Articles | Volume 13, issue 12
https://doi.org/10.5194/bg-13-3833-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-13-3833-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
01 Jul 2016
Research article |
| 01 Jul 2016
Identification and analysis of low-molecular-weight dissolved organic carbon in subglacial basal ice ecosystems by ion chromatography
Emily C. O'Donnell
CORRESPONDING AUTHOR
School of Geography, University of Nottingham, University Park,
Nottingham, NG7 2RD, UK
Bristol Glaciology Centre, School of Geographical Sciences, University
Road, Bristol, BS8 1SS, UK
Jemma L. Wadham
Bristol Glaciology Centre, School of Geographical Sciences, University
Road, Bristol, BS8 1SS, UK
Grzegorz P. Lis
Bristol Glaciology Centre, School of Geographical Sciences, University
Road, Bristol, BS8 1SS, UK
Martyn Tranter
Bristol Glaciology Centre, School of Geographical Sciences, University
Road, Bristol, BS8 1SS, UK
Amy E. Pickard
School of Geosciences, University of Edinburgh, Kings Buildings, West
Mains Rd, Edinburgh, EH9 3JN, UK
Marek Stibal
Department of Ecology, Charles University in Prague, Vinicna 7, 128 44
Prague 2, Czech Republic
Paul Dewsbury
Thermo Fisher Scientific, Stafford House, 1 Boundary Park, Hemel
Hempstead, Hertfordshire HP27 GE4, UK
Sean Fitzsimons
Department of Geography, University of Otago, P.O. Box 56, Dunedin, Otago
9056, New Zealand
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Jemma Louise Wadham, Jonathan Hawkings, Jon Telling, Dave Chandler, Jon Alcock, Emily O'Donnell, Preeti Kaur, Elizabeth Bagshaw, Martyn Tranter, Andre Tedstone, and Peter Nienow
Biogeosciences, 13, 6339–6352, https://doi.org/10.5194/bg-13-6339-2016, https://doi.org/10.5194/bg-13-6339-2016, 2016
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Fjord and continental shelf environments in the polar regions are host to some of the planet's most productive ecosystems and support economically important fisheries. A key limiting nutrient for many of these marine phytoplankton is nitrogen. Here we evaluate the potential for a melting Greenland Ice Sheet to supply nitrogen to Arctic coastal ecosystems. We show nitrogen fluxes of a similar order of magnitude to one large Arctic river but yields that are double those typical of Arctic rivers.
E. C. Lawson, J. L. Wadham, M. Tranter, M. Stibal, G. P. Lis, C. E. H. Butler, J. Laybourn-Parry, P. Nienow, D. Chandler, and P. Dewsbury
Biogeosciences, 11, 4015–4028, https://doi.org/10.5194/bg-11-4015-2014, https://doi.org/10.5194/bg-11-4015-2014, 2014
Lou-Anne Chevrollier, Adrien Wehrlé, Joseph M. Cook, Norbert Pirk, Liane G. Benning, Alexandre M. Anesio, and Martyn Tranter
EGUsphere, https://doi.org/10.5194/egusphere-2024-2583, https://doi.org/10.5194/egusphere-2024-2583, 2024
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Light absorbing particles (LAPs) are often present as a mixture on snow surfaces, and are important to disentangle because their darkening effect varies, but also because the processes governing their presence and accumulation on snow surfaces are different. This study presents a novel method to retrieve the concentration and albedo reducing effect of different LAPs present at the snow surface from surface spectral albedo. The method is then successfully applied to observations on seasonal snow.
Guillaume Lamarche-Gagnon, Marek Stibal, Alexandre M. Anesio, Jemma L. Wadham, Jon Hawkings, Lukáš Falteisek, Kristýna Vrbická, Petra Klímová, Jakub D. Žárský, Tyler J. Kohler, Elizabeth A. Bagshaw, Jade E. Hatton, Alex D. Beaton, and Jon Telling
EGUsphere, https://doi.org/10.5194/egusphere-2024-817, https://doi.org/10.5194/egusphere-2024-817, 2024
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To better understand the microbial ecosystems that underlay Earth’s glaciers, studies often rely on indirect sampling of the subglacial environment via proglacial meltwater runoff. Our research in Greenland reveals that fluctuations in glacier melt can affect microbial composition in runoff, highlighting important biases often overlooked in studies of glacial runoff that might skew interpretations as to the subglacial origin of microbial communities exported within meltwaters.
Eva L. Doting, Ian T. Stevens, Anne M. Kellerman, Pamela E. Rossel, Runa Antony, Amy M. McKenna, Martyn Tranter, Liane G. Benning, Robert G. M. Spencer, Jon R. Hawkings, and Alexandre M. Anesio
EGUsphere, https://doi.org/10.5194/egusphere-2024-492, https://doi.org/10.5194/egusphere-2024-492, 2024
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This study provides new insights into the transformation of dissolved organic matter (DOM) that takes place as meltwater flows through the porous crust of weathering ice that covers glacier ice surfaces during the melt season. Movement of water through the weathering crust is slow, allowing microorganisms and sunlight to alter the DOM in glacial meltwater. This is important as supraglacial meltwaters deliver DOM and nutrients to microorganisms living in downstream receiving aquatic environments.
Beatriz Gill-Olivas, Jon Telling, Mark Skidmore, and Martyn Tranter
Biogeosciences, 20, 929–943, https://doi.org/10.5194/bg-20-929-2023, https://doi.org/10.5194/bg-20-929-2023, 2023
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Microbial ecosystems have been found in all subglacial environments sampled to date. Yet, little is known of the sources of energy and nutrients that sustain these microbial populations. This study shows that crushing of sedimentary rocks, which contain organic carbon, carbonate and sulfide minerals, along with previously weathered silicate minerals, produces a range of compounds and nutrients which can be utilised by the diverse suite of microbes that inhabit glacier beds.
Miranda J. Nicholes, Christopher Williamson, Martyn Tranter, Alexandra Holland, Marian Yallop, and Alexandre Anesio
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-227, https://doi.org/10.5194/bg-2020-227, 2020
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This incubation experiment assessed the role of solar radiation and heterotrophic bacteria in the degradation of organic carbon in surface ice of the Greenland Ice Sheet. Although ultraviolet radiation was found to alter carbon composition, heterotrophic degradation caused the greatest changes to both carbon composition and quantity. Both processes are likely interlinked within the surface ice and are fundamental to controlling the composition of carbon exported to downstream environments.
Moya L. Macdonald, Jemma L. Wadham, Dickon Young, Chris R. Lunder, Ove Hermansen, Guillaume Lamarche-Gagnon, and Simon O'Doherty
Atmos. Chem. Phys., 20, 7243–7258, https://doi.org/10.5194/acp-20-7243-2020, https://doi.org/10.5194/acp-20-7243-2020, 2020
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Climate change has caused glaciers in the Arctic to shrink, uncovering new soils. We used field measurements to study the exchange of a group of gases involved in ozone destruction, called halocarbons, between these new soils and the atmosphere. We found that mats of cyanobacteria, early colonisers of soils, are linked to a larger-than-expected exchange of halocarbons with the atmosphere. We also found that gases which are commonly thought to be marine in origin were released from these soils.
Andrew J. Tedstone, Joseph M. Cook, Christopher J. Williamson, Stefan Hofer, Jenine McCutcheon, Tristram Irvine-Fynn, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 521–538, https://doi.org/10.5194/tc-14-521-2020, https://doi.org/10.5194/tc-14-521-2020, 2020
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Albedo describes how much light that hits a surface is reflected without being absorbed. Low-albedo ice surfaces melt more quickly. There are large differences in the albedo of bare-ice areas of the Greenland Ice Sheet. They are caused both by dark glacier algae and by the condition of the underlying ice. Changes occur over centimetres to metres, so satellites do not always detect real albedo changes. Estimates of melt made using satellite measurements therefore tend to be underestimates.
Joseph M. Cook, Andrew J. Tedstone, Christopher Williamson, Jenine McCutcheon, Andrew J. Hodson, Archana Dayal, McKenzie Skiles, Stefan Hofer, Robert Bryant, Owen McAree, Andrew McGonigle, Jonathan Ryan, Alexandre M. Anesio, Tristram D. L. Irvine-Fynn, Alun Hubbard, Edward Hanna, Mark Flanner, Sathish Mayanna, Liane G. Benning, Dirk van As, Marian Yallop, James B. McQuaid, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 309–330, https://doi.org/10.5194/tc-14-309-2020, https://doi.org/10.5194/tc-14-309-2020, 2020
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Melting of the Greenland Ice Sheet (GrIS) is a major source of uncertainty for sea level rise projections. Ice-darkening due to the growth of algae has been recognized as a potential accelerator of melting. This paper measures and models the algae-driven ice melting and maps the algae over the ice sheet for the first time. We estimate that as much as 13 % total runoff from the south-western GrIS can be attributed to these algae, showing that they must be included in future mass balance models.
Alexandra T. Holland, Christopher J. Williamson, Fotis Sgouridis, Andrew J. Tedstone, Jenine McCutcheon, Joseph M. Cook, Ewa Poniecka, Marian L. Yallop, Martyn Tranter, Alexandre M. Anesio, and The Black & Bloom Group
Biogeosciences, 16, 3283–3296, https://doi.org/10.5194/bg-16-3283-2019, https://doi.org/10.5194/bg-16-3283-2019, 2019
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This paper provides a preliminary data set for dissolved nutrient abundance in the Dark Zone of the Greenland Ice Sheet. This 15-year marked darkening has since been attributed to glacier algae blooms, yet has not been accounted for in current melt rate models. We conclude that the dissolved organic phase dominates surface ice environments and that factors other than macronutrient limitation control the extent and magnitude of the glacier algae blooms.
Joseph M. Cook, Andrew J. Hodson, Alex S. Gardner, Mark Flanner, Andrew J. Tedstone, Christopher Williamson, Tristram D. L. Irvine-Fynn, Johan Nilsson, Robert Bryant, and Martyn Tranter
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Biological growth darkens snow and ice, causing it to melt faster. This is often referred to as
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Andrew J. Tedstone, Jonathan L. Bamber, Joseph M. Cook, Christopher J. Williamson, Xavier Fettweis, Andrew J. Hodson, and Martyn Tranter
The Cryosphere, 11, 2491–2506, https://doi.org/10.5194/tc-11-2491-2017, https://doi.org/10.5194/tc-11-2491-2017, 2017
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The bare ice albedo of the south-west Greenland ice sheet varies dramatically between years. The reasons are unclear but likely involve darkening by inorganic particulates, cryoconite and ice algae. We use satellite imagery to examine dark ice dynamics and climate model outputs to find likely climatological controls. Outcropping particulates can explain the spatial extent of dark ice, but the darkening itself is likely due to ice algae growth controlled by meltwater and light availability.
Amy E. Pickard, Kate V. Heal, Andrew R. McLeod, and Kerry J. Dinsmore
Biogeosciences, 14, 1793–1809, https://doi.org/10.5194/bg-14-1793-2017, https://doi.org/10.5194/bg-14-1793-2017, 2017
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Peatland catchments export significant volumes of photoreactive carbon to aquatic systems, particularly headwater streams. Delivery of photoreactive material is subject to seasonal variation, and is also influenced by the timing and magnitude of rainfall events. We suggest that photoprocessing of peatland derived carbon may contribute to carbon dioxide emissions from aquatic systems, although considerable uncertainty remains as to how much material is processed
in situwithin these systems.
Sophie L. Nixon, Jon P. Telling, Jemma L. Wadham, and Charles S. Cockell
Biogeosciences, 14, 1445–1455, https://doi.org/10.5194/bg-14-1445-2017, https://doi.org/10.5194/bg-14-1445-2017, 2017
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Despite their permanently cold and dark characteristics, subglacial environments (glacier ice–sediment interface) are known to harbour active microbial communities. However, the role of microbial iron cycling in these environments is poorly understood. Here we show that subglacial sediments harbour active iron-reducing microorganisms, and they appear to be cold-adapted. These results may have important implications for global biogeochemical iron cycling and export to marine ecosystems.
Jemma Louise Wadham, Jonathan Hawkings, Jon Telling, Dave Chandler, Jon Alcock, Emily O'Donnell, Preeti Kaur, Elizabeth Bagshaw, Martyn Tranter, Andre Tedstone, and Peter Nienow
Biogeosciences, 13, 6339–6352, https://doi.org/10.5194/bg-13-6339-2016, https://doi.org/10.5194/bg-13-6339-2016, 2016
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Fjord and continental shelf environments in the polar regions are host to some of the planet's most productive ecosystems and support economically important fisheries. A key limiting nutrient for many of these marine phytoplankton is nitrogen. Here we evaluate the potential for a melting Greenland Ice Sheet to supply nitrogen to Arctic coastal ecosystems. We show nitrogen fluxes of a similar order of magnitude to one large Arctic river but yields that are double those typical of Arctic rivers.
James A. Bradley, Sandra Arndt, Marie Šabacká, Liane G. Benning, Gary L. Barker, Joshua J. Blacker, Marian L. Yallop, Katherine E. Wright, Christopher M. Bellas, Jonathan Telling, Martyn Tranter, and Alexandre M. Anesio
Biogeosciences, 13, 5677–5696, https://doi.org/10.5194/bg-13-5677-2016, https://doi.org/10.5194/bg-13-5677-2016, 2016
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Soil development following glacier retreat was characterized using a novel integrated field, laboratory and modelling approach in Svalbard. We found community shifts in bacteria, which were responsible for driving cycles in carbon and nutrients. Allochthonous inputs were also important in sustaining bacterial production. This study shows how an integrated model–data approach can improve understanding and obtain a more holistic picture of soil development in an increasingly ice-free future world.
Robert Raiswell, Jon R. Hawkings, Liane G. Benning, Alex R. Baker, Ros Death, Samuel Albani, Natalie Mahowald, Michael D. Krom, Simon W. Poulton, Jemma Wadham, and Martyn Tranter
Biogeosciences, 13, 3887–3900, https://doi.org/10.5194/bg-13-3887-2016, https://doi.org/10.5194/bg-13-3887-2016, 2016
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Iron is an essential nutrient for plankton growth. One important source of iron is wind-blown dust. The polar oceans are remote from dust sources but melting icebergs supply sediment that contains iron which is potentially available to plankton. We show that iceberg sediments contain more potentially bioavailable iron than wind-blown dust. Iceberg sources will become increasingly important with climate change and increased plankton growth can remove more carbon dioxide from the atmosphere.
D. M. Chandler, J. D. Alcock, J. L. Wadham, S. L. Mackie, and J. Telling
The Cryosphere, 9, 487–504, https://doi.org/10.5194/tc-9-487-2015, https://doi.org/10.5194/tc-9-487-2015, 2015
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The Greenland Ice Sheet surface shows a diverse range of characteristics, and hosts active microbial communities in debris-rich ''cryoconite holes'' (CHs). Field and satellite data for a complete melt season revealed significant links between surface albedo, CH coverage and biological activity. This suggests satellites may be able to monitor CH biological processes. Nevertheless, caution is needed when extrapolating point measurements of biological processes to larger space and time scales.
E. C. Lawson, J. L. Wadham, M. Tranter, M. Stibal, G. P. Lis, C. E. H. Butler, J. Laybourn-Parry, P. Nienow, D. Chandler, and P. Dewsbury
Biogeosciences, 11, 4015–4028, https://doi.org/10.5194/bg-11-4015-2014, https://doi.org/10.5194/bg-11-4015-2014, 2014
R. Death, J. L. Wadham, F. Monteiro, A. M. Le Brocq, M. Tranter, A. Ridgwell, S. Dutkiewicz, and R. Raiswell
Biogeosciences, 11, 2635–2643, https://doi.org/10.5194/bg-11-2635-2014, https://doi.org/10.5194/bg-11-2635-2014, 2014
N. J. Cullen, P. Sirguey, T. Mölg, G. Kaser, M. Winkler, and S. J. Fitzsimons
The Cryosphere, 7, 419–431, https://doi.org/10.5194/tc-7-419-2013, https://doi.org/10.5194/tc-7-419-2013, 2013
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Devika Varma, Laura Villanueva, Nicole J. Bale, Pierre Offre, Gert-Jan Reichart, and Stefan Schouten
Biogeosciences, 21, 4875–4888, https://doi.org/10.5194/bg-21-4875-2024, https://doi.org/10.5194/bg-21-4875-2024, 2024
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Archaeal hydroxylated tetraether lipids are increasingly used as temperature indicators in marine settings, but the factors influencing their distribution are still unclear. Analyzing membrane lipids of two thaumarchaeotal strains showed that the growth phase of the cultures does not affect the lipid distribution, but growth temperature profoundly affects the degree of cyclization of these lipids. Also, the abundance of these lipids is species-specific and is not influenced by temperature.
William Kew, Allison Myers-Pigg, Christine H. Chang, Sean M. Colby, Josie Eder, Malak M. Tfaily, Jeffrey Hawkes, Rosalie K. Chu, and James C. Stegen
Biogeosciences, 21, 4665–4679, https://doi.org/10.5194/bg-21-4665-2024, https://doi.org/10.5194/bg-21-4665-2024, 2024
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Natural organic matter (NOM) is often studied via Fourier transform mass spectrometry (FTMS), which identifies organic molecules as mass spectra peaks. The intensity of peaks is data that is often discarded due to technical concerns. We review the theory behind these concerns and show they are supported empirically. However, simulations show that ecological analyses of NOM data that include FTMS peak intensities are often valid. This opens a path for robust use of FTMS peak intensities for NOM.
Adam J. Fagan, Tatsuro Tanioka, Alyse A. Larkin, Jenna A. Lee, Nathan S. Garcia, and Adam C. Martiny
Biogeosciences, 21, 4239–4250, https://doi.org/10.5194/bg-21-4239-2024, https://doi.org/10.5194/bg-21-4239-2024, 2024
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Climate change is anticipated to influence the biological pump by altering phytoplankton nutrient distribution. In our research, we collected measurements of particulate matter concentrations during two oceanographic field studies. We observed systematic variations in organic matter concentrations and ratios across the Atlantic Ocean. From statistical modeling, we determined that these variations are associated with differences in the availability of essential nutrients for phytoplankton growth.
Sebastian I. Cantarero, Edgart Flores, Harry Allbrook, Paulina Aguayo, Cristian A. Vargas, John E. Tamanaha, J. Bentley C. Scholz, Lennart T. Bach, Carolin R. Löscher, Ulf Riebesell, Balaji Rajagopalan, Nadia Dildar, and Julio Sepúlveda
Biogeosciences, 21, 3927–3958, https://doi.org/10.5194/bg-21-3927-2024, https://doi.org/10.5194/bg-21-3927-2024, 2024
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Our study explores lipid remodeling in response to environmental stress, specifically how cell membrane chemistry changes. We focus on intact polar lipids in a phytoplankton community exposed to diverse stressors in a mesocosm experiment. The observed remodeling indicates acyl chain recycling for energy storage in intact polar lipids during stress, reallocating resources based on varying growth conditions. This understanding is essential to grasp the system's impact on cellular pools.
Mengke Wang, Peng Zhang, Huishan Li, Guisen Deng, Deliang Kong, Sifang Kong, and Junjian Wang
Biogeosciences, 21, 2691–2704, https://doi.org/10.5194/bg-21-2691-2024, https://doi.org/10.5194/bg-21-2691-2024, 2024
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We developed and applied complementary analyses to characterize molecular-level carbon traits for water-grown and soil-grown fine roots. The adaptive strategy of developing more labile carbon in water-grown roots accelerated root decomposition and counteracted the decelerated effects of anoxia on decomposition, highlighting an indirect effect of environmental change on belowground carbon cycling.
Maria G. Digernes, Yasemin V. Bodur, Martí Amargant-Arumí, Oliver Müller, Jeffrey A. Hawkes, Stephen G. Kohler, Ulrike Dietrich, Marit Reigstad, and Maria Lund Paulsen
EGUsphere, https://doi.org/10.5194/egusphere-2024-1314, https://doi.org/10.5194/egusphere-2024-1314, 2024
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Dissolved (DOM) and particulate organic matter (POM) are in constant exchange, but usually studied as distinct entities. We investigated the dynamics between POM and DOM in a sub-Arctic fjord across different seasons by conducting bi-monthly aggregation-dissolution experiments. During the productive period, POM concentrations increased in the experiment while DOM molecules became more recalcitrant. During the winter period, POM concentrations decreased whereas DOM molecules became more labile.
Zhe-Xuan Zhang, Edith Parlanti, Christelle Anquetil, Jérôme Morelle, Anniet M. Laverman, Alexandre Thibault, Elisa Bou, and Arnaud Huguet
Biogeosciences, 21, 2227–2252, https://doi.org/10.5194/bg-21-2227-2024, https://doi.org/10.5194/bg-21-2227-2024, 2024
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Bacterial tetraethers have important implications for palaeoclimate reconstruction. However, fundamental understanding of how these lipids are transformed from land to sea and which environmental factors influence their distributions is lacking. Here, we investigate the sources of brGDGTs and brGMGTs and the factors controlling their distributions in a large dataset (n=237). We propose a novel proxy (RIX) to trace riverine runoff, which is applicable in modern systems and in paleorecord.
Youcheng Bai, Marie-Alexandrine Sicre, Jian Ren, Vincent Klein, Haiyan Jin, and Jianfang Chen
Biogeosciences, 21, 689–709, https://doi.org/10.5194/bg-21-689-2024, https://doi.org/10.5194/bg-21-689-2024, 2024
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Algal biomarkers were used to assess sea ice and pelagic algal production across the western Arctic Ocean with changing sea-ice conditions. They show three distinct areas along with a marked latitudinal gradient of sea ice over pelagic algal production in surface sediments that are reflected by the H-Print index. Our data also show that efficient grazing consumption accounted for the dramatic decrease of diatom-derived biomarkers in sediments compared to that of particulate matter.
Hanxiao Wang, Zhifei Liu, Jiaying Li, Baozhi Lin, Yulong Zhao, Xiaodong Zhang, Junyuan Cao, Jingwen Zhang, Hongzhe Song, and Wenzhuo Wang
Biogeosciences, 20, 5109–5123, https://doi.org/10.5194/bg-20-5109-2023, https://doi.org/10.5194/bg-20-5109-2023, 2023
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The sinking of zooplankton fecal pellets is a key process in the marine biological carbon pump. This study presents carbon export of four shapes of fecal pellets from two time-series sediment traps in the South China Sea. The results show that the sinking fate of fecal pellets is regulated by marine primary productivity, deep-dwelling zooplankton community, and deep-sea currents in the tropical marginal sea, thus providing a new perspective for exploring the carbon cycle in the world ocean.
Rebecca J. Chmiel, Riss M. Kell, Deepa Rao, Dawn M. Moran, Giacomo R. DiTullio, and Mak A. Saito
Biogeosciences, 20, 3997–4027, https://doi.org/10.5194/bg-20-3997-2023, https://doi.org/10.5194/bg-20-3997-2023, 2023
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Cobalt is an important micronutrient for plankton, yet it is often scarce throughout the oceans. A 2017/2018 expedition to coastal Antarctica, including regions of the Amundsen Sea and the Ross Sea, discovered lower concentrations of cobalt compared to two past expeditions in 2005 and 2006, particularly for the type of cobalt preferred as a nutrient by phytoplankton. This loss may be due to changing inputs of other nutrients, causing higher uptake of cobalt by plankton over the last decade.
Alessio Leins, Danaé Bregnard, Andrea Vieth-Hillebrand, Stefanie Poetz, Florian Eichinger, Guillaume Cailleau, Pilar Junier, and Simona Regenspurg
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-159, https://doi.org/10.5194/bg-2023-159, 2023
Revised manuscript accepted for BG
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Organic matter and microbial fluid analyses are rarely taken into account in the geothermal industry and research. However, they can have a significant effect on the efficiency of geothermal power production. We discovered a high variety in organic compound composition in our samples and were able to differentiate it with regard to various sources (e.g. artificial and biogenic). Furthermore, the microbial diversity undergoes significant changes within the flow path of a geothermal power plant.
Emily B. Graham, Hyun-Seob Song, Samantha Grieger, Vanessa A. Garayburu-Caruso, James C. Stegen, Kevin D. Bladon, and Allison N. Myers-Pigg
Biogeosciences, 20, 3449–3457, https://doi.org/10.5194/bg-20-3449-2023, https://doi.org/10.5194/bg-20-3449-2023, 2023
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Intensifying wildfires are increasing pyrogenic organic matter (PyOM) production and its impact on water quality. Recent work indicates that PyOM may have a greater impact on aquatic biogeochemistry than previously assumed, driven by higher bioavailability. We provide a full assessment of the potential bioavailability of PyOM across its chemical spectrum. We indicate that PyOM can be actively transformed within the river corridor and, therefore, may be a growing source of riverine C emissions.
Nora Richter, Ellen C. Hopmans, Danica Mitrović, Pedro M. Raposeiro, Vítor Gonçalves, Ana C. Costa, Linda A. Amaral-Zettler, Laura Villanueva, and Darci Rush
Biogeosciences, 20, 2065–2098, https://doi.org/10.5194/bg-20-2065-2023, https://doi.org/10.5194/bg-20-2065-2023, 2023
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Bacteriohopanepolyols (BHPs) are a diverse class of lipids produced by bacteria across a wide range of environments. This study characterizes the diversity of BHPs in lakes and coastal lagoons in the Azores Archipelago, as well as a co-culture enriched for methanotrophs. We highlight the potential of BHPs as taxonomic markers for bacteria associated with certain ecological niches, which can be preserved in sedimentary records.
Andrea Scheibe, Carlos A. Sierra, and Marie Spohn
Biogeosciences, 20, 827–838, https://doi.org/10.5194/bg-20-827-2023, https://doi.org/10.5194/bg-20-827-2023, 2023
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We explored carbon cycling in soils in three climate zones in Chile down to a depth of 6 m, using carbon isotopes. Our results show that microbial activity several meters below the soil surface is mostly fueled by recently fixed carbon and that strong decomposition of soil organic matter only occurs in the upper decimeters of the soils. The study shows that different layers of the critical zone are tightly connected and that processes in the deep soil depend on recently fixed carbon.
Melissa Sophia Schwab, Hannah Gies, Chantal Valérie Freymond, Maarten Lupker, Negar Haghipour, and Timothy Ian Eglinton
Biogeosciences, 19, 5591–5616, https://doi.org/10.5194/bg-19-5591-2022, https://doi.org/10.5194/bg-19-5591-2022, 2022
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The majority of river studies focus on headwater or floodplain systems, while often neglecting intermediate river segments. Our study on the subalpine Sihl River bridges the gap between streams and lowlands and demonstrates that moderately steep river segments are areas of significant instream alterations, modulating the export of organic carbon over short distances.
Lisa Noll, Shasha Zhang, Qing Zheng, Yuntao Hu, Florian Hofhansl, and Wolfgang Wanek
Biogeosciences, 19, 5419–5433, https://doi.org/10.5194/bg-19-5419-2022, https://doi.org/10.5194/bg-19-5419-2022, 2022
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Cleavage of proteins to smaller nitrogen compounds allows microorganisms and plants to exploit the largest nitrogen reservoir in soils and is considered the bottleneck in soil organic nitrogen cycling. Results from soils covering a European transect show that protein turnover is constrained by soil geochemistry, shifts in climate and associated alterations in soil weathering and should be considered as a driver of soil nitrogen availability with repercussions on carbon cycle processes.
Muhammed Fatih Sert, Helge Niemann, Eoghan P. Reeves, Mats A. Granskog, Kevin P. Hand, Timo Kekäläinen, Janne Jänis, Pamela E. Rossel, Bénédicte Ferré, Anna Silyakova, and Friederike Gründger
Biogeosciences, 19, 2101–2120, https://doi.org/10.5194/bg-19-2101-2022, https://doi.org/10.5194/bg-19-2101-2022, 2022
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We investigate organic matter composition in the Arctic Ocean water column. We collected seawater samples from sea ice to deep waters at six vertical profiles near an active hydrothermal vent and its plume. In comparison to seawater, we found that the organic matter in waters directly affected by the hydrothermal plume had different chemical composition. We suggest that hydrothermal processes may influence the organic matter distribution in the deep ocean.
Charlotte Haugk, Loeka L. Jongejans, Kai Mangelsdorf, Matthias Fuchs, Olga Ogneva, Juri Palmtag, Gesine Mollenhauer, Paul J. Mann, P. Paul Overduin, Guido Grosse, Tina Sanders, Robyn E. Tuerena, Lutz Schirrmeister, Sebastian Wetterich, Alexander Kizyakov, Cornelia Karger, and Jens Strauss
Biogeosciences, 19, 2079–2094, https://doi.org/10.5194/bg-19-2079-2022, https://doi.org/10.5194/bg-19-2079-2022, 2022
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Buried animal and plant remains (carbon) from the last ice age were freeze-locked in permafrost. At an extremely fast eroding permafrost cliff in the Lena Delta (Siberia), we found this formerly frozen carbon well preserved. Our results show that ongoing degradation releases substantial amounts of this carbon, making it available for future carbon emissions. This mobilisation at the studied cliff and also similarly eroding sites bear the potential to affect rivers and oceans negatively.
Aleksandar I. Goranov, Andrew S. Wozniak, Kyle W. Bostick, Andrew R. Zimmerman, Siddhartha Mitra, and Patrick G. Hatcher
Biogeosciences, 19, 1491–1514, https://doi.org/10.5194/bg-19-1491-2022, https://doi.org/10.5194/bg-19-1491-2022, 2022
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Wildfire-derived molecules are ubiquitous in the aquatic environment, but their biological fate remains understudied. We have evaluated the compositional changes that occur to wildfire-derived molecules after incubation with soil microbes. We observe a significant degradation but also a production of numerous new labile molecules. Our results indicate that wildfire-derived molecules can be broken down and the carbon and nitrogen therein can be incorporated into microbial food webs.
Edgart Flores, Sebastian I. Cantarero, Paula Ruiz-Fernández, Nadia Dildar, Matthias Zabel, Osvaldo Ulloa, and Julio Sepúlveda
Biogeosciences, 19, 1395–1420, https://doi.org/10.5194/bg-19-1395-2022, https://doi.org/10.5194/bg-19-1395-2022, 2022
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In this study, we investigate the chemical diversity and abundance of microbial lipids as markers of organic matter sources in the deepest points of the Atacama Trench sediments and compare them to similar lipid stocks in shallower surface sediments and in the overlying water column. We evaluate possible organic matter provenance and some potential chemical adaptations of the in situ microbial community to the extreme conditions of high hydrostatic pressure in hadal realm.
Birgit Gaye, Niko Lahajnar, Natalie Harms, Sophie Anna Luise Paul, Tim Rixen, and Kay-Christian Emeis
Biogeosciences, 19, 807–830, https://doi.org/10.5194/bg-19-807-2022, https://doi.org/10.5194/bg-19-807-2022, 2022
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Amino acids were analyzed in a large number of samples of particulate and dissolved organic matter from coastal regions and the open ocean. A statistical analysis produced two new biogeochemical indicators. An indicator of sinking particle and sediment degradation (SDI) traces the degradation of organic matter from the surface waters into the sediments. A second indicator shows the residence time of suspended matter in the ocean (RTI).
Zoë R. van Kemenade, Laura Villanueva, Ellen C. Hopmans, Peter Kraal, Harry J. Witte, Jaap S. Sinninghe Damsté, and Darci Rush
Biogeosciences, 19, 201–221, https://doi.org/10.5194/bg-19-201-2022, https://doi.org/10.5194/bg-19-201-2022, 2022
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Anaerobic ammonium oxidation (anammox) is an important nitrogen-removal process in the ocean. We assess the distribution of bacteriohopanetetrol-x (BHT-x), used to trace past anammox, along a redox gradient in the water column of the Benguela upwelling system. BHT-x / BHT ratios of >0.18 correspond to the presence of living anammox bacteria and oxygen levels <50 μmol L−1. This allows for a more robust application of BHT-x to trace past marine anammox and deoxygenation in dynamic marine systems.
Jia-Jang Hung, Ching-Han Tung, Zong-Ying Lin, Yuh-ling Lee Chen, Shao-Hung Peng, Yen-Huei Lin, and Li-Shan Tsai
Biogeosciences, 18, 5141–5162, https://doi.org/10.5194/bg-18-5141-2021, https://doi.org/10.5194/bg-18-5141-2021, 2021
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We report measured active and passive fluxes and their controlling mechanisms in the northern South China Sea (NSCS). The total fluxes were higher than most reports in open oceans, indicating the significance of NSCS in atmospheric CO2 uptake and in storing that CO2 in the ocean’s interior. Winter cooling and extreme events enhanced nutrient availability and elevated fluxes. Global warming may have profound impacts on reducing ocean’s uptake and storage of CO2 in subtropical–tropical oceans.
Jens Daniel Müller, Bernd Schneider, Ulf Gräwe, Peer Fietzek, Marcus Bo Wallin, Anna Rutgersson, Norbert Wasmund, Siegfried Krüger, and Gregor Rehder
Biogeosciences, 18, 4889–4917, https://doi.org/10.5194/bg-18-4889-2021, https://doi.org/10.5194/bg-18-4889-2021, 2021
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Based on profiling pCO2 measurements from a field campaign, we quantify the biomass production of a cyanobacteria bloom in the Baltic Sea, the export of which would foster deep water deoxygenation. We further demonstrate how this biomass production can be accurately reconstructed from long-term surface measurements made on cargo vessels in combination with modelled temperature profiles. This approach enables a better understanding of a severe concern for the Baltic’s good environmental status.
Alexander Braun, Marina Spona-Friedl, Maria Avramov, Martin Elsner, Federico Baltar, Thomas Reinthaler, Gerhard J. Herndl, and Christian Griebler
Biogeosciences, 18, 3689–3700, https://doi.org/10.5194/bg-18-3689-2021, https://doi.org/10.5194/bg-18-3689-2021, 2021
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It is known that CO2 fixation by photoautotrophic organisms is the major sink from the atmosphere. While biologists are aware that CO2 fixation also occurs in heterotrophic organisms, this route of inorganic carbon, and its quantitative role, is hardly recognized in biogeochemistry. We demonstrate that a considerable amount of CO2 is fixed annually through anaplerotic reactions in heterotrophic organisms, and a significant quantity of inorganic carbon is temporally sequestered in biomass.
Jonathan H. Raberg, David J. Harning, Sarah E. Crump, Greg de Wet, Aria Blumm, Sebastian Kopf, Áslaug Geirsdóttir, Gifford H. Miller, and Julio Sepúlveda
Biogeosciences, 18, 3579–3603, https://doi.org/10.5194/bg-18-3579-2021, https://doi.org/10.5194/bg-18-3579-2021, 2021
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BrGDGT lipids are a proxy for temperature in lake sediments, but other parameters like pH can influence them, and seasonality can affect the temperatures they record. We find a warm-season bias at 43 new high-latitude sites. We also present a new method that deconvolves the effects of temperature, pH, and conductivity and generate global calibrations for these variables. Our study provides new paleoclimate tools, insight into brGDGTs at the biochemical level, and a new method for future study.
Charlotte L. Spencer-Jones, Erin L. McClymont, Nicole J. Bale, Ellen C. Hopmans, Stefan Schouten, Juliane Müller, E. Povl Abrahamsen, Claire Allen, Torsten Bickert, Claus-Dieter Hillenbrand, Elaine Mawbey, Victoria Peck, Aleksandra Svalova, and James A. Smith
Biogeosciences, 18, 3485–3504, https://doi.org/10.5194/bg-18-3485-2021, https://doi.org/10.5194/bg-18-3485-2021, 2021
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Long-term ocean temperature records are needed to fully understand the impact of West Antarctic Ice Sheet collapse. Glycerol dialkyl glycerol tetraethers (GDGTs) are powerful tools for reconstructing ocean temperature but can be difficult to apply to the Southern Ocean. Our results show active GDGT synthesis in relatively warm depths of the ocean. This research improves the application of GDGT palaeoceanographic proxies in the Southern Ocean.
Alec W. Armstrong, Leanne Powers, and Michael Gonsior
Biogeosciences, 18, 3367–3390, https://doi.org/10.5194/bg-18-3367-2021, https://doi.org/10.5194/bg-18-3367-2021, 2021
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Living things decay into organic matter, which can dissolve into water (like tea brewing). Tea receives its color by absorbing light. Similarly, this material absorbs light, which can then cause chemical reactions that change it. By measuring changes in these optical properties, we found that materials from some places are more sensitive to light than others. Comparing sensitivity to light helps us understand where these materials come from and what happens as they move through water.
Ben J. Fisher, Johan C. Faust, Oliver W. Moore, Caroline L. Peacock, and Christian März
Biogeosciences, 18, 3409–3419, https://doi.org/10.5194/bg-18-3409-2021, https://doi.org/10.5194/bg-18-3409-2021, 2021
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Organic carbon can be protected from microbial degradation in marine sediments through association with iron minerals on 1000-year timescales. Despite the importance of this carbon sink, our spatial and temporal understanding of iron-bound organic carbon interactions globally is poor. Here we show that caution must be applied when comparing quantification of iron-bound organic carbon extracted by different methods as the extraction strength and method specificity can be highly variable.
Mark A. Stevenson, Suzanne McGowan, Emma J. Pearson, George E. A. Swann, Melanie J. Leng, Vivienne J. Jones, Joseph J. Bailey, Xianyu Huang, and Erika Whiteford
Biogeosciences, 18, 2465–2485, https://doi.org/10.5194/bg-18-2465-2021, https://doi.org/10.5194/bg-18-2465-2021, 2021
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We link detailed stable isotope and biomarker analyses from the catchments of three Arctic upland lakes on Disko Island (West Greenland) to a recent dated sediment core to understand how carbon cycling has changed over the past ~500 years. We find that the carbon deposited in sediments in these upland lakes is predominately sourced from in-lake production due to the catchment's limited terrestrial vegetation and elevation and that recent increases in algal production link with climate change.
Nadine T. Smit, Laura Villanueva, Darci Rush, Fausto Grassa, Caitlyn R. Witkowski, Mira Holzheimer, Adriaan J. Minnaard, Jaap S. Sinninghe Damsté, and Stefan Schouten
Biogeosciences, 18, 1463–1479, https://doi.org/10.5194/bg-18-1463-2021, https://doi.org/10.5194/bg-18-1463-2021, 2021
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Soils from an everlasting fire (gas seep) in Sicily, Italy, reveal high relative abundances of novel uncultivated mycobacteria and unique 13C-depleted mycocerosic acids (multi-methyl branched fatty acids) close to the main gas seep. Our results imply that mycocerosic acids in combination with their depleted δ13C values offer a new biomarker tool to study the role of soil mycobacteria as hydrocarbon consumers in the modern and past global carbon cycle.
Marcus P. S. Badger
Biogeosciences, 18, 1149–1160, https://doi.org/10.5194/bg-18-1149-2021, https://doi.org/10.5194/bg-18-1149-2021, 2021
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Reconstructing ancient atmospheric CO2 is an important aim of palaeoclimate science in order to understand the Earth's climate system. One method, the alkenone proxy based on molecular fossils of coccolithophores, has been recently shown to be ineffective at low-to-moderate CO2 levels. In this paper I show that this is likely due to changes in the biogeochemistry of the coccolithophores when there is low carbon availability, but for much of the Cenozoic the alkenone proxy should have utility.
Loes G. J. van Bree, Francien Peterse, Allix J. Baxter, Wannes De Crop, Sigrid van Grinsven, Laura Villanueva, Dirk Verschuren, and Jaap S. Sinninghe Damsté
Biogeosciences, 17, 5443–5463, https://doi.org/10.5194/bg-17-5443-2020, https://doi.org/10.5194/bg-17-5443-2020, 2020
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Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are used as a paleothermometer based on their temperature dependence in global soils, but aquatic production complicates their use in lakes. BrGDGTs in the water column of Lake Chala, East Africa, respond to oxygen conditions and mixing. Changes in their signal can be linked to bacterial community composition rather than membrane adaptation to changing conditions. Their integrated signal in the sediment reflects mean air temperature.
Alexandra N. Loginova, Andrew W. Dale, Frédéric A. C. Le Moigne, Sören Thomsen, Stefan Sommer, David Clemens, Klaus Wallmann, and Anja Engel
Biogeosciences, 17, 4663–4679, https://doi.org/10.5194/bg-17-4663-2020, https://doi.org/10.5194/bg-17-4663-2020, 2020
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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.
Gerard J. M. Versteegh, Alexander J. P. Houben, and Karin A. F. Zonneveld
Biogeosciences, 17, 3545–3561, https://doi.org/10.5194/bg-17-3545-2020, https://doi.org/10.5194/bg-17-3545-2020, 2020
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Anoxic sediments mostly contain much more organic matter than oxic ones, and therefore organic matter in anoxic settings is often considered to be preserved better than in oxic settings. However, through the analysis of the same fossil dinoflagellate cyst species from both oxic and anoxic settings, we show that at a molecular level the preservation in the oxic sediments may be better since in the anoxic setting the cyst macromolecule has been altered by postdepositional modification.
Jingjing Guo, Miriam Glendell, Jeroen Meersmans, Frédérique Kirkels, Jack J. Middelburg, and Francien Peterse
Biogeosciences, 17, 3183–3201, https://doi.org/10.5194/bg-17-3183-2020, https://doi.org/10.5194/bg-17-3183-2020, 2020
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The fluxes of soil organic carbon (OC) transport from land to sea are poorly constrained, mostly due to the lack of a specific tracer for soil OC. Here we evaluate the use of specific molecules derived from soil bacteria as a tracer for soil OC in a small river catchment. We find that the initial soil signal is lost upon entering the aquatic environment. However, the local environmental history of the catchment is reflected by these molecules in the lake sediments that act as their sink.
Zhuo-Yi Zhu, Joanne Oakes, Bradley Eyre, Youyou Hao, Edwin Sien Aun Sia, Shan Jiang, Moritz Müller, and Jing Zhang
Biogeosciences, 17, 2473–2485, https://doi.org/10.5194/bg-17-2473-2020, https://doi.org/10.5194/bg-17-2473-2020, 2020
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Samples were collected in August 2016 in the Rajang River and its estuary, with tropical forest in the river basin and peatland in the estuary. Organic matter composition was influenced by transportation in the river basin, whereas peatland added clear biodegraded parts to the fluvial organic matter, which implies modification of the initial lability and/or starting points in the subsequent degradation and alternation processes after the organic matter enters the sea.
Wenjie Xiao, Yasong Wang, Yongsheng Liu, Xi Zhang, Linlin Shi, and Yunping Xu
Biogeosciences, 17, 2135–2148, https://doi.org/10.5194/bg-17-2135-2020, https://doi.org/10.5194/bg-17-2135-2020, 2020
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The hadal zone (6–11 km depth) is the least explored habitat on Earth. We studied microbial branched glycerol dialkyl glycerol tetraethers (brGDGTs) in the Challenger Deep, Mariana Trench. One unique feature is the strong predominance of 6-methyl brGDGT, which likely reflects an adaption of brGDGT-producing bacteria to alkaline seawater and low temperature. BrGDGTs, with elemental and isotopic data, suggest an autochthonous product for brGDGT. A new approach is proposed for brGDGT sourcing.
Yuge Bai, Edisson Subdiaga, Stefan B. Haderlein, Heike Knicker, and Andreas Kappler
Biogeosciences, 17, 683–698, https://doi.org/10.5194/bg-17-683-2020, https://doi.org/10.5194/bg-17-683-2020, 2020
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Biogeochemical processes of SOM are key for greenhouse gas emission and water quality. We extracted SOM by water or by NaOH–HCl under oxic–anoxic conditions. Chemical and anoxic extractions lead to higher SOM electron exchange capacities, resulting in stimulation of microbial Fe(III) reduction. Therefore, aqueous pH-neutral SOM extracts should be used to reflect environmental SOM redox processes, and artifacts of chemical extractions need to be considered when evaluating SOM redox processes.
Yan Shen, Volker Thiel, Pablo Suarez-Gonzalez, Sebastiaan W. Rampen, and Joachim Reitner
Biogeosciences, 17, 649–666, https://doi.org/10.5194/bg-17-649-2020, https://doi.org/10.5194/bg-17-649-2020, 2020
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Today, sterols are widespread in plants, animals, and fungi but are almost absent in the oldest rocks. Microbial mats, representing the earliest complex ecosystems on Earth, were omnipresent in Precambrian marine environments and may have degraded the sterols at that time. Here we analyze the distribution of sterols through a microbial mat. This provides insight into how variations in biological and nonbiological factors affect the preservation of sterols in modern and ancient microbial mats.
Sarah Coffinet, Travis B. Meador, Lukas Mühlena, Kevin W. Becker, Jan Schröder, Qing-Zeng Zhu, Julius S. Lipp, Verena B. Heuer, Matthew P. Crump, and Kai-Uwe Hinrichs
Biogeosciences, 17, 317–330, https://doi.org/10.5194/bg-17-317-2020, https://doi.org/10.5194/bg-17-317-2020, 2020
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This study deals with two membrane lipids called BDGTs and PDGTs. Membrane lipids are molecules forming the cell envelope of all organisms. Different organisms produce different lipids thus they can be used to detect the presence of specific organisms in the environment. We analyzed the structure of these new lipids and looked for potential producers. We found that they are likely made by microbes emitting methane below the sediment surface and could be used to track these specific microbes.
Ying Wu, Kun Zhu, Jing Zhang, Moritz Müller, Shan Jiang, Aazani Mujahid, Mohd Fakharuddin Muhamad, and Edwin Sien Aun Sia
Biogeosciences, 16, 4517–4533, https://doi.org/10.5194/bg-16-4517-2019, https://doi.org/10.5194/bg-16-4517-2019, 2019
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Our understanding of terrestrial organic matter (TOM) in tropical peat-draining rivers remains limited, especially in Southeast Asia. We explored the characteristics of TOM via bulk parameters and lignin phenols of sediment in Malaysia. This showed that the most important plant source of the organic matter in these rivers is woody angiosperm C3 plants with limited diagenetic alteration. This slower degradation of TOM may be a link to higher total nitrogen content, especially for the small river.
Caitlyn R. Witkowski, Sylvain Agostini, Ben P. Harvey, Marcel T. J. van der Meer, Jaap S. Sinninghe Damsté, and Stefan Schouten
Biogeosciences, 16, 4451–4461, https://doi.org/10.5194/bg-16-4451-2019, https://doi.org/10.5194/bg-16-4451-2019, 2019
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Carbon dioxide concentrations (pCO2) in the atmosphere play an integral role in Earth system dynamics, especially climate. Past climates help us understand future ones, but reconstructing pCO2 over the geologic record remains a challenge. This research demonstrates new approaches for exploring past pCO2 via the carbon isotope fractionation in general algal lipids, which we test over a high CO2 gradient from a naturally occurring CO2 seep.
Yongli Zhou, Patrick Martin, and Moritz Müller
Biogeosciences, 16, 2733–2749, https://doi.org/10.5194/bg-16-2733-2019, https://doi.org/10.5194/bg-16-2733-2019, 2019
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We found that peatlands in coastal Sarawak, Borneo, export extremely humified organic matter, which dominates the riverine organic matter pool and conservatively mixes with seawater, while the freshly produced fraction is low and stable in concentration at all salinities. We estimated that terrigenous fractions, which showed high photolability, still account for 20 % of the coastal dissolved organic carbon pool, implying the importance of peat-derived organic matter in the coastal carbon cycle.
Kristin Doering, Claudia Ehlert, Philippe Martinez, Martin Frank, and Ralph Schneider
Biogeosciences, 16, 2163–2180, https://doi.org/10.5194/bg-16-2163-2019, https://doi.org/10.5194/bg-16-2163-2019, 2019
Alexandra N. Loginova, Sören Thomsen, Marcus Dengler, Jan Lüdke, and Anja Engel
Biogeosciences, 16, 2033–2047, https://doi.org/10.5194/bg-16-2033-2019, https://doi.org/10.5194/bg-16-2033-2019, 2019
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High primary production in the Peruvian upwelling system is followed by rapid heterotrophic utilization of organic matter and supports the formation of one of the most intense oxygen minimum zones (OMZs) in the world. Here, we estimated vertical fluxes of oxygen and dissolved organic matter (DOM) from the surface to the OMZ. Our results suggest that DOM remineralization substantially reduces oxygen concentration in the upper water column and controls the shape of the upper oxycline.
Carolina Cisternas-Novoa, Frédéric A. C. Le Moigne, and Anja Engel
Biogeosciences, 16, 927–947, https://doi.org/10.5194/bg-16-927-2019, https://doi.org/10.5194/bg-16-927-2019, 2019
Short summary
Short summary
We investigate the composition and vertical fluxes of POM in two deep basins of the Baltic Sea (GB: Gotland Basin and LD: Landsort Deep). The two basins showed different O2 regimes resulting from the intrusion of oxygen-rich water from the North Sea that ventilated the deep waters in GB, but not in LD.
In GB, O2 intrusions lead to a high abundance of manganese oxides that aggregate with POM, altering its composition and vertical flux and contributing to a higher POC transfer efficiency in GB.
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Short summary
We use a novel ion chromatographic analysis that provides the first identification and quantification of major low-molecular-weight dissolved organic carbon (LMW-DOC) compounds in basal ice. LMW-DOC concentrations were dependent on the bioavailability of the overridden organic carbon, which in turn was influenced by the type of overridden material. The overridden material may thus act as a direct (abiotic leaching) and indirect (microbial cycling) source of DOC to the subglacial environment.
We use a novel ion chromatographic analysis that provides the first identification and...
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