BG - recent papers

Point-scale organic-matter decomposition in streambeds is weakly associated with reach-scale respiration

2026-06-17T18:28:51+02:00

Point-scale organic-matter decomposition in streambeds is weakly associated with reach-scale respiration
James C. Stegen, Morgan Barnes, Dillman Delgado, Brieanne Forbes, Vanessa A. Garayburu-Caruso, Amy E. Goldman, Maggi Laan, Sophia McKever, Peter Regier, Lupita Renteria, and Scott D. Tiegs
Biogeosciences, 23, 3981–3993, https://doi.org/10.5194/bg-23-3981-2026, 2026
Streams move and break down organic material, but it is unclear how small-scale decomposition relates to larger scale respiration. We used cotton strips at 48 sites in the Yakima River Basin, Washington, to measure decomposition and different components of river respiration. Decomposition tracked whole-river respiration more than local sediment activity, showing that spatial variation in decomposition results from integrated watershed features.

Surface area and Ω-aragonite oversaturation as controls of the runaway precipitation process in ocean alkalinity enhancement

2026-06-16T18:28:51+02:00

Surface area and Ω-aragonite oversaturation as controls of the runaway precipitation process in ocean alkalinity enhancement
Niels Suitner, Jens Hartmann, Selene Varliero, Giulia Faucher, Philipp Suessle, and Charly A. Moras
Biogeosciences, 23, 3965–3980, https://doi.org/10.5194/bg-23-3965-2026, 2026
Alkalinity leakage limits the efficiency of ocean alkalinity enhancement. Drivers of this process remain unquantified, restricting accurate assessments. The induced runaway process can be modeled using surface area and aragonite oversaturation as key factors. This study proposes a framework for improving predictability of alkalinity loss due to runaway precipitation, emphasizing the need for field experiments to validate theoretical models concerning dilution and particle sinking processes.

In situ production of hybrid N2O in dust-rich Antarctic ice

2026-06-15T18:28:51+02:00

In situ production of hybrid N2O in dust-rich Antarctic ice
Lison Soussaintjean, Jochen Schmitt, Joël Savarino, J. Andy Menking, Edward J. Brook, Barbara Seth, Vladimir Lipenkov, Thomas Röckmann, and Hubertus Fischer
Biogeosciences, 23, 3939–3963, https://doi.org/10.5194/bg-23-3939-2026, 2026
Nitrous oxide (N2O) produced in dust-rich Antarctic ice complicates the reconstruction of past atmospheric levels from ice core records. Using isotope analysis, we show that N2O forms from two nitrogen precursors, one being nitrate. For the first time, we demonstrate that the site preference (SP) of N2O reflects the isotopic difference between these precursors, not the production pathway, which challenges the common interpretation of SP.

Rapid soil degradation following deforestation in Eastern Africa

2026-06-15T18:28:51+02:00

Rapid soil degradation following deforestation in Eastern Africa
Laura Summerauer, Fernando Bamba, Bendicto Akoraebirungi, Ahurra Wobusobozi, Marijn Bauters, Travis William Drake, Negar Haghipour, Clovis Kabaseke, Daniel Muhindo, Landry Cizungu Ntaboba, Leonardo Ramirez-Lopez, Johan Six, Daniel Wasner, and Sebastian Doetterl
Biogeosciences, 23, 3907–3938, https://doi.org/10.5194/bg-23-3907-2026, 2026
Deforestation for croplands on tropical hillslopes causes severe soil degradation and loss of fertile topsoil. We found that this leads to a steep decline in soil fertility, including organic carbon, nitrogen, and phosphorus. This makes the land unproductive, often leading farmers to abandon it. Replanting with Eucalyptus trees doesn't restore fertility. This degradation leads to cropland lifespans of only 145±56 years and poses a serious threat to future food production.

Denitrification as the dominant process in nitrous oxide production in the water column of two eutrophic reservoirs

2026-06-12T18:28:51+02:00

Denitrification as the dominant process in nitrous oxide production in the water column of two eutrophic reservoirs
Elizabeth Leon-Palmero, Claudia Frey, Bess B. Ward, Rafael Morales-Baquero, and Isabel Reche
Biogeosciences, 23, 3887–3905, https://doi.org/10.5194/bg-23-3887-2026, 2026
Reservoirs act as nitrogen sinks and emit nitrous oxide, a potent greenhouse gas and major ozone-depleting substance. We studied two reservoirs and found that nitrification and denitrification produce nitrous oxide in the water column, but denitrification is the main source, fueled by fresh organic matter from phytoplankton. Our results also suggest that nitrous oxide is actively consumed. This study highlights the need to include reservoirs in global nitrous oxide budgets.

Understanding the resilient carbon cycle response to the 2014–2015 Blob event in the Gulf of Alaska using a regional ocean biogeochemical model

2026-06-12T18:28:51+02:00

Understanding the resilient carbon cycle response to the 2014–2015 Blob event in the Gulf of Alaska using a regional ocean biogeochemical model
Yumi Abe, Takamitsu Ito, Amanda H. V. Timmerman, Christopher T. Reinhard, and Joseph P. Montoya
Biogeosciences, 23, 3871–3885, https://doi.org/10.5194/bg-23-3871-2026, 2026
Marine heatwaves are defined by periods of unusually high sea temperature. Although warmer seawater usually reduces the ocean’s ability to absorb carbon dioxide, observations in the Gulf of Alaska showed a surprising drop in carbon dioxide during the 2014–2015 “Blob” heatwave. Using an ocean biogeochemical model, we found that this decline resulted from reduced dissolved inorganic carbon caused by weakened physical supply in winter 2013, just before the Blob began.

Global quantification of the eco-hydrological co-benefits of soil carbon sequestration

2026-06-11T18:28:51+02:00

Global quantification of the eco-hydrological co-benefits of soil carbon sequestration
Inne Vanderkelen, Marie-Estelle Demory, Sean Swenson, David M. Lawrence, Benjamin D. Stocker, Myke Koopmans, and Édouard L. Davin
Biogeosciences, 23, 3829–3854, https://doi.org/10.5194/bg-23-3829-2026, 2026
Soil carbon sequestration supports climate mitigation and may enhance water availability. Using a global land model, we show that increased soil organic carbon improves water retention in the root zone and reduces runoff, particularly in dry, sandy regions. Although hydrological changes are modest, they are systematic and suggest co-benefits for vegetation productivity and ecosystem resilience in water-limited areas.

Bomb-radiocarbon signal suggests that soil carbon contributes to chlorophyll a in archival oak leaves

2026-06-11T18:28:51+02:00

Bomb-radiocarbon signal suggests that soil carbon contributes to chlorophyll a in archival oak leaves
Naoto F. Ishikawa, Hisami Suga, Tessa S. van der Voort, Reto Nyffeler, Nanako O. Ogawa, Negar Haghipour, Lukas Wacker, Timothy I. Eglinton, and Naohiko Ohkouchi
Biogeosciences, 23, 3855–3869, https://doi.org/10.5194/bg-23-3855-2026, 2026
The main finding of this work is that chlorophyll a in plant leaves is made from atmospheric CO2 (83 ± 2 %) as well as soil carbon (17 ± 2 %), the latter of which is older than 1000 years. The results suggest that radiocarbon age and provenance within a single tree are more diverse than previously thought.

Diatom–environment relationships and limnological variability: an updated quantitative tool for palaeoclimatology on sub-Antarctic Macquarie Island

2026-06-11T18:28:51+02:00

Diatom–environment relationships and limnological variability: an updated quantitative tool for palaeoclimatology on sub-Antarctic Macquarie Island
Caitlin A. Selfe, Karina Meredith, Liza McDonough, Justine Shaw, Stephen J. Roberts, and Krystyna M. Saunders
Biogeosciences, 23, 3807–3827, https://doi.org/10.5194/bg-23-3807-2026, 2026
This study presents an updated diatom–conductivity model to reconstruct past Southern Hemisphere westerly wind strength from lake sediments on sub-Antarctic Macquarie Island. We analysed diatom–environment relationships using seasonal and multi-year water chemistry and isotope data. Diatoms respond strongly to changes in lake water conductivity driven by wind-blown sea spray. The model provides a reliable tool for tracking long-term wind patterns and understanding past and future climate change.

Addition of brackish water to tundra soils does not inhibit methane production: implications for Arctic coastal methane production

2026-06-10T18:28:51+02:00

Addition of brackish water to tundra soils does not inhibit methane production: implications for Arctic coastal methane production
Alexie Roy-Lafontaine, Rebecca Lee, Peter M. J. Douglas, Dustin Whalen, and André Pellerin
Biogeosciences, 23, 3777–3792, https://doi.org/10.5194/bg-23-3777-2026, 2026
Arctic coastlines are eroding and flooding as the climate warms, but their role in releasing methane, a potent greenhouse gas, is not well understood. We collected soil and sediment samples near Tuktoyaktuk, Canada, and tested methane production when exposed to seawater in laboratory incubations. We expected seawater to suppress methane production, but coastal soils instead produced more methane than inland sites. Arctic coasts may therefore be an overlooked source of methane to the atmosphere.

Snowmelt timing constrains green-up but not peak productivity in alpine grasslands of the western Pyrenees

2026-06-10T18:28:51+02:00

Snowmelt timing constrains green-up but not peak productivity in alpine grasslands of the western Pyrenees
Pablo Domínguez-Aguilar, Jesús Revuelto, Simon Gascoin, and Juan I. López-Moreno
Biogeosciences, 23, 3793–3806, https://doi.org/10.5194/bg-23-3793-2026, 2026
We studied how the timing of snowmelt shapes the growth of mountain grasslands in the western Spanish Pyrenees. Using satellite images and weather data, we found that grasslands start growing as soon as the snow disappears. However their maximum growth, occurring during summer, depends more on temperature and rainfall than on snowmelt timing. Stable patterns of productive areas suggest a strong influence of local soil and microclimate in shaping the distribution of vegetation and its growth.

Ideas and perspectives: Max MACS – constraining the potential global scale of Marine Anoxic Carbon Storage for CO2 removal

2026-06-08T18:28:51+02:00

Ideas and perspectives: Max MACS – constraining the potential global scale of Marine Anoxic Carbon Storage for CO2 removal
Morgan Reed Raven, Nitai Amiel, Dror L. Angel, James P. Barry, Thomas M. Blattmann, Laura Boicenco, Antoine Crémière, Natalya Evans, Nora Gallarotti, Sebastian Haas, Jan-Hendrik Hehemann, Peter Krost, Pranay Lal, David Lordkipanidze, Tiia Luostarinen, Aaron M. Martinez, Allison J. Matzelle, Selma Menabit, Mihaela Muresan, Andreas Neumann, Jean-Daniel Paris, Christopher R. Pearce, Nick Reynard, Daniel L. Sanchez, Florence Schubotz, Violeta Slabakova, Adrian Stanica, Elena Stoica, Andrew K. Sweetman, Tina Treude, Yoana G. Voynova, and Nikolaos D. Zarokanellos
Biogeosciences, 23, 3755–3776, https://doi.org/10.5194/bg-23-3755-2026, 2026
In addition to reducing emissions, vast quantities of CO2 will need to be removed from the atmosphere to meet climate goals. One strategy known as Marine Anoxic Carbon Storage (MACS) would bury plant carbon for thousands of years in parts in the ocean that lack oxygen, where carbon preservation can be highly efficient. We evaluate the environmental and other impacts of hypothetical large-scale MACS deployment from an interdisciplinary, international perspective and present a research roadmap.

The impact of large-scale macroalgae cultivation and harvesting strategies on the marine carbon dioxide removal efficacy and marine biogeochemistry

2026-06-05T18:28:51+02:00

The impact of large-scale macroalgae cultivation and harvesting strategies on the marine carbon dioxide removal efficacy and marine biogeochemistry
Prima Anugerahanti, Julien Palmiéri, Chelsey A. Baker, Ekaterina Popova, and Andrew Yool
Biogeosciences, 23, 3735–3754, https://doi.org/10.5194/bg-23-3735-2026, 2026
We used an ocean biogeochemistry model to investigate carbon removal potential of large-scale seaweed cultivation with multiple operational strategies and how it impacts the natural ocean biogeochemistry. Our results show that cultivation can increase atmospheric CO2 uptake, but at the expense of decreasing nutrients, phytoplankton production, and deoxygenation. These trade-offs need to be assessed before considering large-scale seaweed cultivation for carbon dioxide removal.

Temperature dependence of the contribution of soil water content to soil respiration in a monsoon influenced temperate deciduous forest

2026-06-04T18:28:51+02:00

Temperature dependence of the contribution of soil water content to soil respiration in a monsoon influenced temperate deciduous forest
Dongmin Seo, Minyoung Lee, Jaeho Lee, and Jaeseok Lee
Biogeosciences, 23, 3723–3734, https://doi.org/10.5194/bg-23-3723-2026, 2026
Based on observations from a temperate deciduous forest, we show that the influence of soil water content on soil respiration depends on soil temperature conditions. The contribution of soil water content was limited below 15 °C but increased above 15 °C. A breakpoint of about 17 °C was identified near the temperature range where this contribution became more evident, suggesting that the relative importance of controlling factors may differ between cooler and warmer soil conditions.

Sedimentary insights into organic matter alteration in Arctic Alaska's saline permafrost

2026-06-03T18:28:51+02:00

Sedimentary insights into organic matter alteration in Arctic Alaska's saline permafrost
Fabian Seemann, Michael Zech, Maren Jenrich, Guido Grosse, Benjamin M. Jones, Claire Treat, Lutz Schirrmeister, Susanne Liebner, and Jens Strauss
Biogeosciences, 23, 3675–3695, https://doi.org/10.5194/bg-23-3675-2026, 2026
Arctic coastal landscapes, like those in northernmost Alaska, are often characterized by saline permafrost which is prone to thawing. We studied six sediment cores to understand how thawing and salinity affect organic matter breakdown and landscape change. Our results show that salinity accelerates organic matter degradation when permafrost thaws. This highlights the overlooked risk of salinity in shaping Arctic landscapes and carbon mineralization as the climate continues to warm.

Colored and fluorescent DOM in the sea-surface microlayer: response to a phytoplankton bloom and photodegradation in a mesocosm study

2026-06-03T18:28:51+02:00

Colored and fluorescent DOM in the sea-surface microlayer: response to a phytoplankton bloom and photodegradation in a mesocosm study
Claudia Thölen, Jochen Wollschläger, Michael G. Novak, Rüdiger Röttgers, and Oliver Zielinski
Biogeosciences, 23, 3697–3721, https://doi.org/10.5194/bg-23-3697-2026, 2026
In a mesocosm study, the investigation of colored and fluorescent dissolved organic matter provided information on its transformation, enrichment, and exchange processes within the sea-surface microlayer and the underlying water. Photodegradation was suggested as the main sink, exceeding microbial alteration, and indicating that light and biological processes, such as the induced phytoplankton bloom, jointly shaped organic matter composition under strong vertical mixing.

The impact of essential climate variables on respiration rates in subpolar and polar planktonic foraminifera

2026-05-29T18:28:51+02:00

The impact of essential climate variables on respiration rates in subpolar and polar planktonic foraminifera
Diane V. Armitage, Nicolaas Glock, Thomas L. Weiss, Mohamed M. Ezat, Adele Westgård, Freya E. Sykes, Julie Meilland, Elwyn de la Vega, Alessio Fabbrini, Tali L. Babila, and Audrey Morley
Biogeosciences, 23, 3655–3673, https://doi.org/10.5194/bg-23-3655-2026, 2026
Here we studied how tiny polar ocean plankton (foraminifera) breathe, using micro-sensors and 3D imaging to see if their respiration changes in responds to climate and environmental change. We found that the dominant polar species, Neogloboquadrina pachyderma, exhibits metabolic stability across large changes in temperature and ocean chemistry. This suggests its shell chemistry is not strongly affected by metabolism, supporting its use for reconstructing past polar ocean climates.

Shoreline exposure controls teal carbon accumulation in boreal lakes

2026-05-28T18:28:51+02:00

Shoreline exposure controls teal carbon accumulation in boreal lakes
Ana Lúcia Lindroth Dauner, Max O. A. Kankainen, Sakari Väkevä, Eero Asmala, Marko Järvinen, Karoliina Koho, and Tom Jilbert
Biogeosciences, 23, 3637–3653, https://doi.org/10.5194/bg-23-3637-2026, 2026
Aquatic vegetated ecosystems are important for global carbon storage, but freshwater shorelines remain understudied. We found that the sedimentary organic carbon (SOC) stocks ranged from 0 to 40.8 kg m−2, with a large spatial variability. Large SOC stocks were found in sheltered areas, with the predominance of fine-grained sediments. In exposed areas, vegetation might also impact SOC accumulation. Accounting for shoreline exposure is crucial for improving regional carbon budget estimates.

Limited iron isotope variation among tissues of a marine fish: a case study of wild chub mackerel (Scomber japonicus)

2026-05-27T18:28:51+02:00

Limited iron isotope variation among tissues of a marine fish: a case study of wild chub mackerel (Scomber japonicus)
Nanako Hasegawa, Yoshio Takahashi, and Takaaki Itai
Biogeosciences, 23, 3605–3614, https://doi.org/10.5194/bg-23-3605-2026, 2026
Iron stable isotope ratios provide a potential tracer of iron metabolism in fish. Here, we report tissue-specific isotope variations in mackerel and evaluate how storage iron as ferritin affects fractionation using speciation analysis. The results show small isotopic differences among tissues, indicating that isotope ratios are primarily controlled by dietary values and intestinal uptake, highlighting the potential of natural isotope patterns as physiological indicators in fish.

Thawing Siberian permafrost stabilizes organic carbon from recent plant litter inputs

2026-05-27T18:28:51+02:00

Thawing Siberian permafrost stabilizes organic carbon from recent plant litter inputs
Christian Knoblauch, Christian Beer, and Carolina Voigt
Biogeosciences, 23, 3615–3635, https://doi.org/10.5194/bg-23-3615-2026, 2026
Carbon release from thawing permafrost receives ample attention since it may cause rising greenhouse gas concentrations in the atmosphere. However, we demonstrate through a 9-year lasting incubation experiment that thawing permafrost stabilizes a substantial amount of fresh plant litter carbon from increasing plant productivity for decades. Although litter carbon is faster decomposed than the permafrost carbon it may contribute to the build-up of organic carbon in thawing permafrost soils.