https://bg.copernicus.org/articles/ Combined list of the recent articles of the journal Biogeosciences and the recent discussion forum Biogeosciences Discussions en https://doi.org/10.5194/bg-23-3981-2026 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. Wed, 17 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3965-2026 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. Tue, 16 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3939-2026 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. Mon, 15 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3907-2026 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. Mon, 15 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3887-2026 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. Fri, 12 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3871-2026 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. Fri, 12 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3829-2026 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. Thu, 11 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3855-2026 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. Thu, 11 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3807-2026 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. Thu, 11 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3777-2026 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. Wed, 10 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3793-2026 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. Wed, 10 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3755-2026 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. Mon, 08 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3735-2026 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. Fri, 05 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3723-2026 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. Thu, 04 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3675-2026 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. Wed, 03 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3697-2026 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. Wed, 03 Jun 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3655-2026 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. Fri, 29 May 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3637-2026 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. Thu, 28 May 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3605-2026 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. Wed, 27 May 2026 18:28:50 +0200 https://doi.org/10.5194/bg-23-3615-2026 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. Wed, 27 May 2026 18:28:50 +0200