Articles | Volume 16, issue 2
https://doi.org/10.5194/bg-16-437-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/bg-16-437-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
25 Jan 2019
Research article |
| 25 Jan 2019
| 25 Jan 2019
Sedimentary alkalinity generation and long-term alkalinity development in the Baltic Sea
Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
Department of Earth Sciences, Geochemistry, Utrecht University, P.O. Box 80.021, 3508 TA Utrecht, the Netherlands
now at: Soil Chemistry and Chemical Soil Quality, Wageningen University, P.O. Box 47, 6700 AA Wageningen, the Netherlands
Xiaole Sun
Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
Daniel C. Reed
Fisheries & Oceans Canada, Bedford Institute of Oceanography, Dartmouth, NS, Canada
Christoph Humborg
Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
Department of Environmental Science and Analytical Chemistry, Stockholm University, 10691, Stockholm, Sweden
Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland
Caroline P. Slomp
Department of Earth Sciences, Geochemistry, Utrecht University, P.O. Box 80.021, 3508 TA Utrecht, the Netherlands
Bo G. Gustafsson
Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, 10900 Hanko, Finland
Related authors
Erik Gustafsson, Bo G. Gustafsson, Martijn Hermans, Christoph Humborg, and Christian Stranne
Geosci. Model Dev., 17, 7157–7179, https://doi.org/10.5194/gmd-17-7157-2024, https://doi.org/10.5194/gmd-17-7157-2024, 2024
Short summary
Short summary
Methane (CH4) cycling in the Baltic Proper is studied through model simulations, enabling a first estimate of key CH4 fluxes. A preliminary budget identifies benthic CH4 release as the dominant source and two main sinks: CH4 oxidation in the water (92 % of sinks) and outgassing to the atmosphere (8 % of sinks). This study addresses CH4 emissions from coastal seas and is a first step toward understanding the relative importance of open-water outgassing compared with local coastal hotspots.
Filippa Fransner, Agneta Fransson, Christoph Humborg, Erik Gustafsson, Letizia Tedesco, Robinson Hordoir, and Jonas Nycander
Biogeosciences, 16, 863–879, https://doi.org/10.5194/bg-16-863-2019, https://doi.org/10.5194/bg-16-863-2019, 2019
Short summary
Short summary
Although rivers carry large amounts of organic material to the oceans, little is known about what fate it meets when it reaches the sea. In this study we are investigating the fate of the carbon in this organic matter by the use of a numerical model in combination with ship measurements from the northern Baltic Sea. Our results suggests that there is substantial remineralization taking place, transforming the organic carbon into CO2, which is released to the atmosphere.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
Short summary
Short summary
In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
Jelle Bijma, Mathilde Hagens, Jens Hammes, Noah Planavsky, Philip A. E. Pogge von Strandmann, Tom Reershemius, Christopher T. Reinhard, Phil Renforth, Tim Jesper Suhrhoff, Sara Vicca, Arthur Vienne, and Dieter A. Wolf-Gladrow
EGUsphere, https://doi.org/10.5194/egusphere-2025-2740, https://doi.org/10.5194/egusphere-2025-2740, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
Enhanced rock weathering is a nature based negative emission technology, that permanently stores CO2. It requires rock-flour to be added to arable land with the help of farmers. To be eligible for carbon credits calls for a simple but scientifically solid, so called, Monitoring, Reporting & Verification” (MRV). We demonstrate that the commonly used carbon-based accounting is ill-suited to close the balance in open systems such as arable land, and argue for cation-based accounting strategy.
Astrid Hylen, Nils Ekeroth, Hannah Berk, Andy W. Dale, Mikhail Kononets, Wytze K. Lenstra, Aada Palo, Anders Tengberg, Sebastiaan J. van de Velde, Stefan Sommer, Caroline P. Slomp, and Per O. J. Hall
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-146, https://doi.org/10.5194/essd-2025-146, 2025
Preprint under review for ESSD
Short summary
Short summary
Phosphorus is an essential element for life and its cycling strongly impact primary production. Here, we present a dataset of sediment-water fluxes of dissolved inorganic phosphorus from the Baltic Sea, an area with a long history of eutrophication. The fluxes were measured in situ with three types of benthic chamber landers at 59 stations over 20 years. The data show clear spatial patterns and will be important for marine management and studies on mechanisms in benthic phosphorus cycling.
Caroline P. Slomp, Martijn Hermans, Niels A. G. M. van Helmond, Silke Severmann, James McManus, Marit R. van Erk, and Sairah Malkin
EGUsphere, https://doi.org/10.5194/egusphere-2025-817, https://doi.org/10.5194/egusphere-2025-817, 2025
Short summary
Short summary
Cable bacteria couple oxidation of sulfide at depth in sediments with reduction of oxygen, nitrate or nitrite near the sediment surface, thereby preventing release of toxic hydrogen sulfide to the overlying water. We show evidence for a diversity of cable bacteria in sediments from hypoxic and anoxic basins along the continental margin of California and Mexico. Cable bacteria activity in this setting is likely periodic and dependent on the supply of organic matter and/or oxygen.
Robin Klomp, Olga M. Żygadłowska, Mike S. M. Jetten, Véronique E. Oldham, Niels A. G. M. van Helmond, Caroline P. Slomp, and Wytze K. Lenstra
Biogeosciences, 22, 751–765, https://doi.org/10.5194/bg-22-751-2025, https://doi.org/10.5194/bg-22-751-2025, 2025
Short summary
Short summary
In marine sediments, dissolved Mn is present as either Mn(III) or Mn(II). We apply a reactive transport model to geochemical data for a seasonally anoxic and sulfidic coastal basin to determine the pathways of formation and removal of dissolved Mn(III) in the sediment. We demonstrate a critical role for reactions with Fe(II) and show evidence for substantial benthic release of dissolved Mn(III). Given the mobility of Mn(III), these findings have important implications for marine Mn cycling.
Abigail E. Robinson, Anna Scaini, Francisco J. Peña, Peter A. Hambäck, Christoph Humborg, and Fernando Jaramillo
EGUsphere, https://doi.org/10.5194/egusphere-2024-3248, https://doi.org/10.5194/egusphere-2024-3248, 2024
Short summary
Short summary
Wetlands are vital for flood control and drought resistance. These benefits are hard to pinpoint because they depend on water storage and movement, which are extremely variable. To address this, we study seasonal patterns of wetland water area using satellite imagery and AI. Out of 43 Swedish wetlands, we identify 6 groups with similar patterns, linking some to flood buffering and others to flood risk. This method can improve wetland management by identifying specific benefits.
Erik Gustafsson, Bo G. Gustafsson, Martijn Hermans, Christoph Humborg, and Christian Stranne
Geosci. Model Dev., 17, 7157–7179, https://doi.org/10.5194/gmd-17-7157-2024, https://doi.org/10.5194/gmd-17-7157-2024, 2024
Short summary
Short summary
Methane (CH4) cycling in the Baltic Proper is studied through model simulations, enabling a first estimate of key CH4 fluxes. A preliminary budget identifies benthic CH4 release as the dominant source and two main sinks: CH4 oxidation in the water (92 % of sinks) and outgassing to the atmosphere (8 % of sinks). This study addresses CH4 emissions from coastal seas and is a first step toward understanding the relative importance of open-water outgassing compared with local coastal hotspots.
Julia Muchowski, Martin Jakobsson, Lars Umlauf, Lars Arneborg, Bo Gustafsson, Peter Holtermann, Christoph Humborg, and Christian Stranne
Ocean Sci., 19, 1809–1825, https://doi.org/10.5194/os-19-1809-2023, https://doi.org/10.5194/os-19-1809-2023, 2023
Short summary
Short summary
We show observational data of highly increased mixing and vertical salt flux rates in a sparsely sampled region of the northern Baltic Sea. Co-located acoustic observations complement our in situ measurements and visualize turbulent mixing with high spatial resolution. The observed mixing is generally not resolved in numerical models of the area but likely impacts the exchange of water between the adjacent basins as well as nutrient and oxygen conditions in the Bothnian Sea.
Wout Krijgsman, Iuliana Vasiliev, Anouk Beniest, Timothy Lyons, Johanna Lofi, Gabor Tari, Caroline P. Slomp, Namik Cagatay, Maria Triantaphyllou, Rachel Flecker, Dan Palcu, Cecilia McHugh, Helge Arz, Pierre Henry, Karen Lloyd, Gunay Cifci, Özgür Sipahioglu, Dimitris Sakellariou, and the BlackGate workshop participants
Sci. Dril., 31, 93–110, https://doi.org/10.5194/sd-31-93-2022, https://doi.org/10.5194/sd-31-93-2022, 2022
Short summary
Short summary
BlackGate seeks to MSP drill a transect to study the impact of dramatic hydrologic change in Mediterranean–Black Sea connectivity by recovering the Messinian to Holocene (~ 7 Myr) sedimentary sequence in the North Aegean, Marmara, and Black seas. These archives will reveal hydrographic, biotic, and climatic transitions studied by a broad scientific community spanning the stratigraphic, tectonic, biogeochemical, and microbiological evolution of Earth’s most recent saline and anoxic giant.
Eva Ehrnsten, Oleg Pavlovitch Savchuk, and Bo Gustav Gustafsson
Biogeosciences, 19, 3337–3367, https://doi.org/10.5194/bg-19-3337-2022, https://doi.org/10.5194/bg-19-3337-2022, 2022
Short summary
Short summary
We studied the effects of benthic fauna, animals living on or in the seafloor, on the biogeochemical cycles of carbon, nitrogen and phosphorus using a model of the Baltic Sea ecosystem. By eating and excreting, the animals transform a large part of organic matter sinking to the seafloor into inorganic forms, which fuel plankton blooms. Simultaneously, when they move around (bioturbate), phosphorus is bound in the sediments. This reduces nitrogen-fixing plankton blooms and oxygen depletion.
Karol Kuliński, Gregor Rehder, Eero Asmala, Alena Bartosova, Jacob Carstensen, Bo Gustafsson, Per O. J. Hall, Christoph Humborg, Tom Jilbert, Klaus Jürgens, H. E. Markus Meier, Bärbel Müller-Karulis, Michael Naumann, Jørgen E. Olesen, Oleg Savchuk, Andreas Schramm, Caroline P. Slomp, Mikhail Sofiev, Anna Sobek, Beata Szymczycha, and Emma Undeman
Earth Syst. Dynam., 13, 633–685, https://doi.org/10.5194/esd-13-633-2022, https://doi.org/10.5194/esd-13-633-2022, 2022
Short summary
Short summary
The paper covers the aspects related to changes in carbon, nitrogen, and phosphorus (C, N, P) external loads; their transformations in the coastal zone; changes in organic matter production (eutrophication) and remineralization (oxygen availability); and the role of sediments in burial and turnover of C, N, and P. Furthermore, this paper also focuses on changes in the marine CO2 system, the structure of the microbial community, and the role of contaminants for biogeochemical processes.
Tanya J. R. Lippmann, Michiel H. in 't Zandt, Nathalie N. L. Van der Putten, Freek S. Busschers, Marc P. Hijma, Pieter van der Velden, Tim de Groot, Zicarlo van Aalderen, Ove H. Meisel, Caroline P. Slomp, Helge Niemann, Mike S. M. Jetten, Han A. J. Dolman, and Cornelia U. Welte
Biogeosciences, 18, 5491–5511, https://doi.org/10.5194/bg-18-5491-2021, https://doi.org/10.5194/bg-18-5491-2021, 2021
Short summary
Short summary
This paper is a step towards understanding the basal peat ecosystem beneath the North Sea. Plant remains followed parallel sequences. Methane concentrations were low with local exceptions, with the source likely being trapped pockets of millennia-old methane. Microbial community structure indicated the absence of a biofilter and was diverse across sites. Large carbon stores in the presence of methanogens and in the absence of methanotrophs have the potential to be metabolized into methane.
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
Short summary
Short summary
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.
Olivier Sulpis, Siv K. Lauvset, and Mathilde Hagens
Ocean Sci., 16, 847–862, https://doi.org/10.5194/os-16-847-2020, https://doi.org/10.5194/os-16-847-2020, 2020
Short summary
Short summary
As direct measurements of seawater carbonate system variables, such as pH, are difficult to obtain, scientists use equilibrium constants to compute them from known variables. Using a compilation of in situ data, we show that the set of equilibrium constants preferred by the community is not consistent with measurements in cold, polar waters, where human-made ocean acidification is spreading rapidly. Closing knowledge gaps regarding seawater carbon chemistry in polar regions should be a priority.
Niels A. G. M. van Helmond, Elizabeth K. Robertson, Daniel J. Conley, Martijn Hermans, Christoph Humborg, L. Joëlle Kubeneck, Wytze K. Lenstra, and Caroline P. Slomp
Biogeosciences, 17, 2745–2766, https://doi.org/10.5194/bg-17-2745-2020, https://doi.org/10.5194/bg-17-2745-2020, 2020
Short summary
Short summary
We studied the removal of phosphorus (P) and nitrogen (N) in the eutrophic Stockholm archipelago (SA). High sedimentation rates and sediment P contents lead to high P burial. Benthic denitrification is the primary nitrate-reducing pathway. Together, these mechanisms limit P and N transport to the open Baltic Sea. We expect that further nutrient load reduction will contribute to recovery of the SA from low-oxygen conditions and that the sediments will continue to remove part of the P and N loads.
Julien Richirt, Bettina Riedel, Aurélia Mouret, Magali Schweizer, Dewi Langlet, Dorina Seitaj, Filip J. R. Meysman, Caroline P. Slomp, and Frans J. Jorissen
Biogeosciences, 17, 1415–1435, https://doi.org/10.5194/bg-17-1415-2020, https://doi.org/10.5194/bg-17-1415-2020, 2020
Short summary
Short summary
The paper presents the response of benthic foraminiferal communities to seasonal absence of oxygen coupled with the presence of hydrogen sulfide, considered very harmful for several living organisms.
Our results suggest that the foraminiferal community mainly responds as a function of the duration of the adverse conditions.
This knowledge is especially useful to better understand the ecology of benthic foraminifera but also in the context of palaeoceanographic interpretations.
Martin Jakobsson, Christian Stranne, Matt O'Regan, Sarah L. Greenwood, Bo Gustafsson, Christoph Humborg, and Elizabeth Weidner
Ocean Sci., 15, 905–924, https://doi.org/10.5194/os-15-905-2019, https://doi.org/10.5194/os-15-905-2019, 2019
Short summary
Short summary
The bottom topography of the Baltic Sea is analysed using the digital depth model from the European Marine Observation and Data Network (EMODnet) published in 2018. Analyses include depth distribution vs. area and seafloor depth variation on a kilometre scale. The limits for the Baltic Sea and analysed sub-basins are from HELCOM. EMODnet is compared with the previously most widely used depth model and the area of deep water exchange between the Bothnian Sea and the Northern Baltic Proper.
Filippa Fransner, Agneta Fransson, Christoph Humborg, Erik Gustafsson, Letizia Tedesco, Robinson Hordoir, and Jonas Nycander
Biogeosciences, 16, 863–879, https://doi.org/10.5194/bg-16-863-2019, https://doi.org/10.5194/bg-16-863-2019, 2019
Short summary
Short summary
Although rivers carry large amounts of organic material to the oceans, little is known about what fate it meets when it reaches the sea. In this study we are investigating the fate of the carbon in this organic matter by the use of a numerical model in combination with ship measurements from the northern Baltic Sea. Our results suggests that there is substantial remineralization taking place, transforming the organic carbon into CO2, which is released to the atmosphere.
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
Short summary
Short summary
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.
Nikki Dijkstra, Mathilde Hagens, Matthias Egger, and Caroline P. Slomp
Biogeosciences, 15, 861–883, https://doi.org/10.5194/bg-15-861-2018, https://doi.org/10.5194/bg-15-861-2018, 2018
Short summary
Short summary
We show that post-depositional formation of iron(II) phosphate as vivianite strongly alters the phosphorus record in sediments of the Bornholm Basin (Baltic Sea). These minerals began to precipitate in the lake sediments just after the last lake–marine transition ~ 7.5 kyr BP, migrated downwards and are now a stable feature. Formation of vivianite may affect sedimentary phosphorus records in other systems as well. This should be considered when using such records to reconstruct past environments.
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
Short summary
Short summary
We determined the aerobic and anaerobic degradation rates of land- and marine-derived organic material in East Siberian shelf sediment. Marine plankton-derived organic carbon was the main source for the oxic dissolved carbon dioxide production, whereas terrestrial organic material significantly contributed to the production of carbon dioxide under anoxic conditions. Our direct degradation rate measurements provide new constraints for the present-day Arctic marine carbon budget.
Jassin Petersen, Christine Barras, Antoine Bézos, Carole La, Lennart J. de Nooijer, Filip J. R. Meysman, Aurélia Mouret, Caroline P. Slomp, and Frans J. Jorissen
Biogeosciences, 15, 331–348, https://doi.org/10.5194/bg-15-331-2018, https://doi.org/10.5194/bg-15-331-2018, 2018
Short summary
Short summary
In Lake Grevelingen, a coastal ecosystem, foraminifera experience important temporal variations in oxygen concentration and in pore water manganese. The high resolution of LA-ICP-MS allows us to analyse the chambers of foraminiferal shells separately and to obtain signals from a series of calcification events. We estimate the variability in Mn/Ca observed within single shells due to biomineralization and show that a substantial part of the signal is related to environmental variability.
Ulrich Kotthoff, Jeroen Groeneveld, Jeanine L. Ash, Anne-Sophie Fanget, Nadine Quintana Krupinski, Odile Peyron, Anna Stepanova, Jonathan Warnock, Niels A. G. M. Van Helmond, Benjamin H. Passey, Ole Rønø Clausen, Ole Bennike, Elinor Andrén, Wojciech Granoszewski, Thomas Andrén, Helena L. Filipsson, Marit-Solveig Seidenkrantz, Caroline P. Slomp, and Thorsten Bauersachs
Biogeosciences, 14, 5607–5632, https://doi.org/10.5194/bg-14-5607-2017, https://doi.org/10.5194/bg-14-5607-2017, 2017
Short summary
Short summary
We present reconstructions of paleotemperature, paleosalinity, and paleoecology from the Little Belt (Site M0059) over the past ~ 8000 years and evaluate the applicability of numerous proxies. Conditions were lacustrine until ~ 7400 cal yr BP. A transition to brackish–marine conditions then occurred within ~ 200 years. Salinity proxies rarely allowed quantitative estimates but revealed congruent results, while quantitative temperature reconstructions differed depending on the proxies used.
Tommaso Tesi, Marc C. Geibel, Christof Pearce, Elena Panova, Jorien E. Vonk, Emma Karlsson, Joan A. Salvado, Martin Kruså, Lisa Bröder, Christoph Humborg, Igor Semiletov, and Örjan Gustafsson
Ocean Sci., 13, 735–748, https://doi.org/10.5194/os-13-735-2017, https://doi.org/10.5194/os-13-735-2017, 2017
Short summary
Short summary
Recent Arctic studies suggest that sea-ice decline and permafrost thawing will affect the phytoplankton in the Arctic Ocean. However, in what way the plankton composition will change as the warming proceeds remains elusive. Here we show that the carbon composition of plankton might change as a function of the enhanced terrestrial organic carbon supply and progressive sea-ice thawing.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
Short summary
Short summary
In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
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
Short summary
Short summary
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.
C. Lenz, T. Jilbert, D.J. Conley, M. Wolthers, and C.P. Slomp
Biogeosciences, 12, 4875–4894, https://doi.org/10.5194/bg-12-4875-2015, https://doi.org/10.5194/bg-12-4875-2015, 2015
M. Hagens, C. P. Slomp, F. J. R. Meysman, D. Seitaj, J. Harlay, A. V. Borges, and J. J. Middelburg
Biogeosciences, 12, 1561–1583, https://doi.org/10.5194/bg-12-1561-2015, https://doi.org/10.5194/bg-12-1561-2015, 2015
Short summary
Short summary
This study looks at the combined impacts of hypoxia and acidification, two major environmental stressors affecting coastal systems, in a seasonally stratified basin. Here, the surface water experiences less seasonality in pH than the bottom water despite higher process rates. This is due to a substantial reduction in the acid-base buffering capacity of the bottom water as it turns hypoxic in summer. This highlights the crucial role of the buffering capacity as a modulating factor in pH dynamics.
A. Sluijs, L. van Roij, G. J. Harrington, S. Schouten, J. A. Sessa, L. J. LeVay, G.-J. Reichart, and C. P. Slomp
Clim. Past, 10, 1421–1439, https://doi.org/10.5194/cp-10-1421-2014, https://doi.org/10.5194/cp-10-1421-2014, 2014
I. Ruvalcaba Baroni, R. P. M. Topper, N. A. G. M. van Helmond, H. Brinkhuis, and C. P. Slomp
Biogeosciences, 11, 977–993, https://doi.org/10.5194/bg-11-977-2014, https://doi.org/10.5194/bg-11-977-2014, 2014
A. F. Bouwman, M. F. P. Bierkens, J. Griffioen, M. M. Hefting, J. J. Middelburg, H. Middelkoop, and C. P. Slomp
Biogeosciences, 10, 1–22, https://doi.org/10.5194/bg-10-1-2013, https://doi.org/10.5194/bg-10-1-2013, 2013
Related subject area
Biogeochemistry: Coastal Ocean
Depositional controls and budget of organic carbon burial in fine-grained sediments of the North Sea – the Helgoland Mud Area as a natural laboratory
Effects of submarine groundwater on nutrient concentration and primary production in a deep bay of the Japan Sea
The bacteria–protist link as a main route of dissolved organic matter across contrasting productivity areas on the Patagonian Shelf
Ocean alkalinity enhancement (OAE) does not cause cellular stress in a phytoplankton community of the subtropical Atlantic Ocean
Reviews and syntheses: On increasing hypoxia in eastern boundary upwelling systems – zooplankton under metabolic stress
Technical note: Testing a new approach for the determination of N2 fixation rates by coupling a membrane equilibrator to a mass spectrometer for long-term observations
Phytoplankton community succession and biogeochemistry in a bloom simulation experiment at an estuary-ocean interface
Long-term variations in pH in coastal waters along the Korean Peninsula
The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes
Evaluating ocean alkalinity enhancement as a carbon dioxide removal strategy in the North Sea
Assessing the impacts of simulated ocean alkalinity enhancement on viability and growth of nearshore species of phytoplankton
Responses of microbial metabolic rates to non-equilibrated silicate- versus calcium-based ocean alkalinity enhancement
High metabolic zinc demand within native Amundsen and Ross sea phytoplankton communities determined by stable isotope uptake rate measurements
The influence of zooplankton and oxygen on the particulate organic carbon flux in the Benguela Upwelling System
Reviews and syntheses: Biological indicators of low-oxygen stress in marine water-breathing animals
Temperature-enhanced effects of iron on Southern Ocean phytoplankton
Riverine nutrient impact on global ocean nitrogen cycle feedbacks and marine primary production in an Earth system model
Spatio-temporal variations in surface Marine Carbonate System properties across the Western Mediterranean Sea using Volunteer Observing Ship data
The Northeast Greenland Shelf as a potential late-summer CO2 source to the atmosphere
Spring-neap tidal cycles modulate the strength of the carbon source at the estuary-coast interface
Technical note: Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP)
Estimates of carbon sequestration potential in an expanding Arctic fjord (Hornsund, Svalbard) affected by dark plumes of glacial meltwater
An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds
Dissolved nitric oxide in the lower Elbe Estuary and the Port of Hamburg area
Variable contribution of wastewater treatment plant effluents to downstream nitrous oxide concentrations and emissions
Improved understanding of eutrophication trends, indicators and problem areas using machine learning
Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait
Amplified bottom water acidification rates on the Bering Sea shelf from 1970–2022
Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification
Ocean alkalinity enhancement using sodium carbonate salts does not lead to measurable changes in Fe dynamics in a mesocosm experiment
Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea
Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania
Multi-model comparison of trends and controls of near-bed oxygen concentration on the northwest European continental shelf under climate change
Picoplanktonic methane production in eutrophic surface waters
Vertical mixing alleviates autumnal oxygen deficiency in the central North Sea
Hypoxia also occurs in small highly turbid estuaries: the example of the Charente (Bay of Biscay)
Seasonality and response of ocean acidification and hypoxia to major environmental anomalies in the southern Salish Sea, North America (2014–2018)
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Variability and drivers of carbonate chemistry at shellfish aquaculture sites in the Salish Sea, British Columbia
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters
Insights into carbonate environmental conditions in the Chukchi Sea
UAV approaches for improved mapping of vegetation cover and estimation of carbon storage of small saltmarshes: examples from Loch Fleet, northeast Scotland
Iron “ore” nothing: benthic iron fluxes from the oxygen-deficient Santa Barbara Basin enhance phytoplankton productivity in surface waters
Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling in the Santa Barbara Basin, California Borderland
Uncertainty in the evolution of northwestern North Atlantic circulation leads to diverging biogeochemical projections
The additionality problem of ocean alkalinity enhancement
Short-term variation in pH in seawaters around coastal areas of Japan: characteristics and forcings
Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords
Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
Daniel Müller, Bo Liu, Walter Geibert, Moritz Holtappels, Lasse Sander, Elda Miramontes, Heidi Taubner, Susann Henkel, Kai-Uwe Hinrichs, Denise Bethke, Ingrid Dohrmann, and Sabine Kasten
Biogeosciences, 22, 2541–2567, https://doi.org/10.5194/bg-22-2541-2025, https://doi.org/10.5194/bg-22-2541-2025, 2025
Short summary
Short summary
Coastal and shelf sediments are the most important sinks for organic carbon (OC) on Earth. We produced a new high-resolution sediment and porewater data set from the Helgoland Mud Area (HMA), North Sea, to determine which depositional factors control the preservation of OC. The burial efficiency is highest in an area of high sedimentation and terrigenous OC. The HMA covers 0.09 % of the North Sea but accounts for 0.76 % of its OC accumulation, highlighting the importance of the depocentre.
Menghong Dong, Xinyu Guo, Takuya Matsuura, Taichi Tebakari, and Jing Zhang
Biogeosciences, 22, 2383–2402, https://doi.org/10.5194/bg-22-2383-2025, https://doi.org/10.5194/bg-22-2383-2025, 2025
Short summary
Short summary
Submarine groundwater discharge (SGD), a common coastal hydrological process that involves submarine inflow of groundwater into the sea, is associated with a large nutrient load. To clarify the distribution of SGD-derived nutrients after release at the bottom of the sea and their contribution to phytoplankton growth in the marine ecosystem, we modeled the SGD process in Toyama Bay using a specialized computer code that can distinguish SGD-derived nutrients from nutrients from other sources.
M. Celeste López-Abbate, John E. Garzón-Cardona, Ricardo Silva, Juan-Carlos Molinero, Laura A. Ruiz-Etcheverry, Ana M. Martínez, Azul S. Gilabert, and Rubén J. Lara
Biogeosciences, 22, 2309–2325, https://doi.org/10.5194/bg-22-2309-2025, https://doi.org/10.5194/bg-22-2309-2025, 2025
Short summary
Short summary
This study explores how microbial dynamics influence the dissolved organic matter (DOM) pool in the Patagonian Shelf. Despite high phytoplankton biomass, selective grazing on fast-growing bacteria led to DOM accumulation, likely due to reduced DOM-consuming bacteria and added egestion compounds. Experiments showed that bacteria not only acted as a carbon sink through mineralization but also transferred assimilated carbon dioxide (CO2) to higher trophic levels.
Librada Ramírez, Leonardo J. Pozzo-Pirotta, Aja Trebec, Víctor Manzanares-Vázquez, José L. Díez, Javier Arístegui, Ulf Riebesell, Stephen D. Archer, and María Segovia
Biogeosciences, 22, 1865–1886, https://doi.org/10.5194/bg-22-1865-2025, https://doi.org/10.5194/bg-22-1865-2025, 2025
Short summary
Short summary
We studied the potential effects of increasing ocean alkalinity on a natural plankton community in subtropical waters of the Atlantic near Gran Canaria, Spain. Alkalinity is the capacity of water to resist acidification, and plankton are usually microscopic plants (phytoplankton) and animals (zooplankton), often less than 2.5 cm in length. This study suggests that increasing ocean alkalinity did not have a significant negative impact on the plankton community studied.
Leissing Frederick, Mauricio A. Urbina, and Ruben Escribano
Biogeosciences, 22, 1839–1852, https://doi.org/10.5194/bg-22-1839-2025, https://doi.org/10.5194/bg-22-1839-2025, 2025
Short summary
Short summary
Evidence shows that due to global warming, zooplankton inhabiting the coastal upwelling zone are exposed to increasing hypoxia affecting their physiology, metabolism, and population dynamics. The adaptive responses of zooplankton to cope with mild/severe hypoxia may depend on trade-offs with other metabolic/energy demands, implying less energy for growth, feeding, and reproduction, with ecological consequences for the zooplankton population and the marine food web.
Sören Iwe, Oliver Schmale, and Bernd Schneider
Biogeosciences, 22, 1767–1779, https://doi.org/10.5194/bg-22-1767-2025, https://doi.org/10.5194/bg-22-1767-2025, 2025
Short summary
Short summary
We present a novel method for quantifying N2 fixation by cyanobacteria, which is crucial in Baltic Sea eutrophication. Our Gas Equilibrium – Membrane-Inlet Mass Spectrometer (GE-MIMS), designed for operation on voluntary observing ships (VOSs), enables large-scale monitoring of surface water N2 depletion caused by N2 fixation. Laboratory tests confirm the device’s accuracy and precision, ensuring that it can complement current methods and contribute valuable data for better understanding N2 fixation in the Baltic Sea.
Jenna Alyson Lee, Joseph H. Vineis, Mathieu A. Poupon, Laure Resplandy, and Bess B. Ward
EGUsphere, https://doi.org/10.5194/egusphere-2025-871, https://doi.org/10.5194/egusphere-2025-871, 2025
Short summary
Short summary
Concurrent sampling of environmental parameters, productivity rates, photopigments, and DNA were used to analyze a 24–L estuarine diatom bloom microcosm. Biogeochemical data and an ecological model indicated that the bloom was terminated by grazing. Comparisons to previous studies revealed (1) additional community and diversity complexity using 18S amplicon vs. traditional pigment–based analyses, and (2) a potential global productivity–diversity relationship using 18S and carbon transport rates.
Yong-Woo Lee, Mi-Ok Park, Seong-Gil Kim, Tae-Hoon Kim, Yong Hwa Oh, Sang Heon Lee, and DongJoo Joung
Biogeosciences, 22, 675–690, https://doi.org/10.5194/bg-22-675-2025, https://doi.org/10.5194/bg-22-675-2025, 2025
Short summary
Short summary
Long-term pH variation in coastal waters along the Korean Peninsula was assessed for the first time, and it exhibited no significant pH change over an 11-year period. This contrasts with the ongoing pH decline in open oceans and other coastal areas. Analysis of environmental data showed that pH is mainly controlled by dissolved oxygen in bottom waters. This suggests that ocean warming could cause a pH decline in Korean coastal waters, affecting many fish and seaweed aquaculture operations.
Kadir Biçe, Tristen Myers Stewart, George G. Waldbusser, and Christof Meile
Biogeosciences, 22, 641–657, https://doi.org/10.5194/bg-22-641-2025, https://doi.org/10.5194/bg-22-641-2025, 2025
Short summary
Short summary
We studied the effect of addition of carbonate minerals on coastal sediments. We carried out laboratory experiments to quantify the dissolution kinetics and integrated these observations into a numerical model that describes biogeochemical cycling in surficial sediments. Using the model, we demonstrate the buffering effect of the mineral additions and their duration. We quantify the effect under different environmental conditions and assess the potential for increased atmospheric CO2 uptake.
Feifei Liu, Ute Daewel, Jan Kossack, Kubilay Timur Demir, Helmuth Thomas, and Corinna Schrum
EGUsphere, https://doi.org/10.5194/egusphere-2025-81, https://doi.org/10.5194/egusphere-2025-81, 2025
Short summary
Short summary
Ocean Alkalinity Enhancement boosts oceanic CO₂ absorption, offering a climate solution. Using a regional model, we examined OAE in the North Sea, revealing that shallow coastal areas achieve higher CO₂ uptake than offshore, where alkalinity is more susceptible to deep-ocean loss. Long-term carbon storage is limited, and pH shifts vary by location. Our findings guide OAE deployment to optimize carbon removal while minimizing ecological effects, supporting global climate mitigation efforts.
Jessica L. Oberlander, Mackenzie E. Burke, Cat A. London, and Hugh L. MacIntyre
Biogeosciences, 22, 499–512, https://doi.org/10.5194/bg-22-499-2025, https://doi.org/10.5194/bg-22-499-2025, 2025
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a promising negative emission technology that results in the net sequestration of atmospheric carbon. In this paper, we assess the potential impact of OAE on phytoplankton through an analysis of prior studies and the effects of simulated OAE on photosynthetic competence. Our findings suggest that there may be little if any significant impact on most phytoplankton studied to date if OAE is conducted in well-flushed, nearshore environments.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, and Ulf Riebesell
Biogeosciences, 21, 5707–5724, https://doi.org/10.5194/bg-21-5707-2024, https://doi.org/10.5194/bg-21-5707-2024, 2024
Short summary
Short summary
This study exposed a natural community to two non-CO2-equilibrated ocean alkalinity enhancement (OAE) deployments using different minerals. Adding alkalinity in this manner decreases dissolved CO2, essential for photosynthesis. While photosynthesis was not suppressed, bloom formation was mildly delayed, potentially impacting marine food webs. The study emphasizes the need for further research on OAE without prior equilibration and on its ecological implications.
Riss M. Kell, Rebecca J. Chmiel, Deepa Rao, Dawn M. Moran, Matthew R. McIlvin, Tristan J. Horner, Nicole L. Schanke, Ichiko Sugiyama, Robert B. Dunbar, Giacomo R. DiTullio, and Mak A. Saito
Biogeosciences, 21, 5685–5706, https://doi.org/10.5194/bg-21-5685-2024, https://doi.org/10.5194/bg-21-5685-2024, 2024
Short summary
Short summary
Despite interest in modeling the biogeochemical uptake and cycling of the trace metal zinc (Zn), measurements of Zn uptake in natural marine phytoplankton communities have not been conducted previously. To fill this gap, we employed a stable isotope uptake rate measurement method to quantify Zn uptake into natural phytoplankton assemblages within the Southern Ocean. Zn demand was high and rapid enough to depress the inventory of Zn available to phytoplankton on seasonal timescales.
Luisa Chiara Meiritz, Tim Rixen, Anja Karin van der Plas, Tarron Lamont, and Niko Lahajnar
Biogeosciences, 21, 5261–5276, https://doi.org/10.5194/bg-21-5261-2024, https://doi.org/10.5194/bg-21-5261-2024, 2024
Short summary
Short summary
Moored and drifting sediment trap experiments in the northern (nBUS) and southern (sBUS) Benguela Upwelling System showed that active carbon fluxes by vertically migrating zooplankton were about 3 times higher in the sBUS than in the nBUS. Despite these large variabilities, the mean passive particulate organic carbon (POC) fluxes were almost equal in the two subsystems. The more intense near-bottom oxygen minimum layer seems to lead to higher POC fluxes and accumulation rates in the nBUS.
Michael R. Roman, Andrew H. Altieri, Denise Breitburg, Erica M. Ferrer, Natalya D. Gallo, Shin-ichi Ito, Karin Limburg, Kenneth Rose, Moriaki Yasuhara, and Lisa A. Levin
Biogeosciences, 21, 4975–5004, https://doi.org/10.5194/bg-21-4975-2024, https://doi.org/10.5194/bg-21-4975-2024, 2024
Short summary
Short summary
Oxygen-depleted ocean waters have increased worldwide. In order to improve our understanding of the impacts of this oxygen loss on marine life it is essential that we develop reliable indicators that track the negative impacts of low oxygen. We review various indicators of low-oxygen stress for marine animals including their use, research needs, and application to confront the challenges of ocean oxygen loss.
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag
Biogeosciences, 21, 4637–4663, https://doi.org/10.5194/bg-21-4637-2024, https://doi.org/10.5194/bg-21-4637-2024, 2024
Short summary
Short summary
Phytoplankton growth in the Southern Ocean (SO) is often limited by low iron (Fe) concentrations. Sea surface warming impacts Fe availability and can affect phytoplankton growth. We used shipboard Fe clean incubations to test how changes in Fe and temperature affect SO phytoplankton. Their abundances usually increased with Fe addition and temperature increase, with Fe being the major factor. These findings imply potential shifts in ecosystem structure, impacting food webs and elemental cycling.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 21, 4469–4493, https://doi.org/10.5194/bg-21-4469-2024, https://doi.org/10.5194/bg-21-4469-2024, 2024
Short summary
Short summary
Marine biological production is highly dependent on the availability of nitrogen and phosphorus. Rivers are the main source of phosphorus to the oceans but poorly represented in global model oceans. We include dissolved nitrogen and phosphorus from river export in a global model ocean and find that the addition of riverine phosphorus affects marine biology on millennial timescales more than riverine nitrogen alone. Globally, riverine phosphorus input increases primary production rates.
David Curbelo-Hernández, David González-Santana, Aridane González-González, J. Magdalena Santana-Casiano, and Melchor González-Dávila
EGUsphere, https://doi.org/10.5194/egusphere-2024-2709, https://doi.org/10.5194/egusphere-2024-2709, 2024
Short summary
Short summary
This study offers a unique high-resolution dataset (2019–2024) on surface physicochemical properties in the western Mediterranean Sea. It reveals accelerated surface warming, significantly altering CO2 levels and pH. Currently a net CO2 sink, the region may become a CO2 source by 2030 due to weakening ingassing. The research highlights the value of VOS lines for monitoring climate impacts and stresses the need for ongoing observation to enhance long-term trend accuracy and future projections.
Esdoorn Willcox, Marcos Lemes, Thomas Juul-Pedersen, Mikael Kristian Sejr, Johnna Marchiano Holding, and Søren Rysgaard
Biogeosciences, 21, 4037–4050, https://doi.org/10.5194/bg-21-4037-2024, https://doi.org/10.5194/bg-21-4037-2024, 2024
Short summary
Short summary
In this work, we measured the chemistry of seawater from samples obtained from different depths and locations off the east coast of the Northeast Greenland National Park to determine what is influencing concentrations of dissolved CO2. Historically, the region has always been thought to take up CO2 from the atmosphere, but we show that it is possible for the region to become a source in late summer. We discuss the variables that may be related to such changes.
Vlad A. Macovei, Louise C. V. Rewrie, Rüdiger Röttgers, and Yoana G. Voynova
EGUsphere, https://doi.org/10.5194/egusphere-2024-2643, https://doi.org/10.5194/egusphere-2024-2643, 2024
Short summary
Short summary
A commercial vessel equipped with scientific instruments regularly travelled between two large macro-tidal estuaries. We found that biogeochemical variability in the outer estuaries is driven by the 14-day spring-neap tidal cycle, with strong effects on dissolved inorganic and organic carbon concentrations and distribution. Since this land-sea interface effect increases the strength of the carbon source to the atmosphere by 74 % during spring tide, it should be accounted for in regional models.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences, 21, 3617–3639, https://doi.org/10.5194/bg-21-3617-2024, https://doi.org/10.5194/bg-21-3617-2024, 2024
Short summary
Short summary
The European Arctic is experiencing rapid regional warming, causing glaciers that terminate in the sea to retreat onto land. Due to this process, the area of a well-studied fjord, Hornsund, has increased by around 100 km2 (40%) since 1976. Combining satellite and in situ data with a mathematical model, we estimated that, despite some negative consequences of glacial meltwater release, such emerging coastal waters could mitigate climate change by increasing carbon uptake and storage by sediments.
Mallory C. Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan R. Carter, and Matthew D. Eisaman
Biogeosciences, 21, 3551–3570, https://doi.org/10.5194/bg-21-3551-2024, https://doi.org/10.5194/bg-21-3551-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Results show that CO2 equilibration occurred on the order of weeks to months, was consistent with values expected from equilibration calculations, and was limited by mineral precipitation at high pH and CaCO3 saturation.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
Biogeosciences, 21, 3425–3440, https://doi.org/10.5194/bg-21-3425-2024, https://doi.org/10.5194/bg-21-3425-2024, 2024
Short summary
Short summary
Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. Dissolved NO was supersaturated in the Elbe Estuary, indicating that it is a source of atmospheric NO. The observed distribution of dissolved NO most likely resulted from nitrification.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
Short summary
Short summary
Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Deep S. Banerjee and Jozef Skakala
EGUsphere, https://doi.org/10.22541/essoar.171405637.76928549/v1, https://doi.org/10.22541/essoar.171405637.76928549/v1, 2024
Short summary
Short summary
Nitrate is a crucial nutrient in oceans. Excess nutrients can trigger uncontrolled algae growth (eutrophication), damaging marine ecosystems. We used a machine learning tool to generate a skilled, gap-free, bi-decadal surface nitrate dataset from sparse observations. This dataset reveals areas on the North West European Shelf at risk of eutrophication, bi-decadal trends in coastal nitrate, and an impact of winter nitrate on spring phytoplankton blooms.
Amanda Y. L. Cheong, Kogila Vani Annammala, Ee Ling Yong, Yongli Zhou, Robert S. Nichols, and Patrick Martin
Biogeosciences, 21, 2955–2971, https://doi.org/10.5194/bg-21-2955-2024, https://doi.org/10.5194/bg-21-2955-2024, 2024
Short summary
Short summary
We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
Darren Pilcher, Jessica Cross, Natalie Monacci, Linquan Mu, Kelly Kearney, Albert Hermann, and Wei Cheng
EGUsphere, https://doi.org/10.5194/egusphere-2024-1096, https://doi.org/10.5194/egusphere-2024-1096, 2024
Short summary
Short summary
The Bering Sea shelf is a highly productive marine ecosystem that is vulnerable to ocean acidification. We use a computational model to simulate the carbon cycle and acidification rates from 1970–2022. The results suggest that bottom water acidification rates are more than twice as great as surface rates. Bottom waters are also naturally more acidic, thus these waters will pass key thresholds known to negatively impact marine organisms, such as red king crab, much sooner than surface waters.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
Short summary
Short summary
In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
Short summary
Short summary
Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
Short summary
Short summary
This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
Short summary
Short summary
Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
Short summary
Short summary
Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
Short summary
Short summary
Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
Short summary
Short summary
We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
Short summary
Short summary
The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
Short summary
Short summary
The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
Short summary
Short summary
Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
Short summary
Short summary
The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
Short summary
Short summary
Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
Short summary
Short summary
Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
Short summary
Short summary
The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
Short summary
Short summary
Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
Short summary
Short summary
We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Tsuneo Ono, Daisuke Muraoka, Masahiro Hayashi, Makiko Yorifuji, Akihiro Dazai, Shigeyuki Omoto, Takehiro Tanaka, Tomohiro Okamura, Goh Onitsuka, Kenji Sudo, Masahiko Fujii, Ryuji Hamanoue, and Masahide Wakita
Biogeosciences, 21, 177–199, https://doi.org/10.5194/bg-21-177-2024, https://doi.org/10.5194/bg-21-177-2024, 2024
Short summary
Short summary
We carried out parallel year-round observations of pH and related parameters in five stations around the Japan coast. It was found that short-term acidified situations with Omega_ar less than 1.5 occurred at four of five stations. Most of such short-term acidified events were related to the short-term low salinity event, and the extent of short-term pH drawdown at high freshwater input was positively correlated with the nutrient concentration of the main rivers that flow into the coastal area.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
Short summary
Short summary
Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Hannah Sharpe, Michel Gosselin, Catherine Lalande, Alexandre Normandeau, Jean-Carlos Montero-Serrano, Khouloud Baccara, Daniel Bourgault, Owen Sherwood, and Audrey Limoges
Biogeosciences, 20, 4981–5001, https://doi.org/10.5194/bg-20-4981-2023, https://doi.org/10.5194/bg-20-4981-2023, 2023
Short summary
Short summary
We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.
Cited articles
Al-Hamdani, Z. and Reker, J.: Towards marine landscapes in the Baltic Sea,
BALANCE Interim Report No. 10, available at: http://balance-eu.org/
(last access: 28 April 2017), 2007.
Andersson, A. J., Mackenzie, F. T., and Lerman, A.: Coastal ocean CO2
– carbonic acid-carbonate sediment system of the Anthropocene, Global
Biogeochem. Cy., 20, GB1S92, https://doi.org/10.1029/2005GB002506, 2006.
Bauer, J. E., Cai, W.-J., Raymond, P. A., Bianchi, T. S., Hopkinson, C. S.,
and Regnier, P. A. G.: The changing carbon cycle of the coastal ocean,
Nature, 504, 61–70, https://doi.org/10.1038/nature12857, 2013.
Beldowski, J., Löffler, A., Schneider, B., and Joensuu, L.: Distribution
and biogeochemical control of total CO2 and total alkalinity in the
Baltic Sea, J. Marine Syst., 81, 252–259, https://doi.org/10.1016/j.jmarsys.2009.12.020,
2010.
Berner, R. A.: Sedimentary pyrite formation: An update, Geochim. Cosmochim.
Ac., 48, 605–615, https://doi.org/10.1016/0016-7037(84)90089-9, 1984.
Boesen, C. and Postma, D.: Pyrite formation in anoxic environments of the
Baltic, Am. J. Sci., 288, 575–603, https://doi.org/10.2475/ajs.288.6.575, 1988.
Boudreau, B. P.: Diagenetic Models and Their Implementation, Springer Berlin
Heidelberg, Berlin, Heidelberg, 1997.
Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P.,
Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K.,
Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W. A., Pitcher, G. C.,
Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M.,
Yasuhara, M., and Zhang, J.: Declining oxygen in the global ocean and coastal
waters, Science, 359, eaam7240, https://doi.org/10.1126/science.aam7240, 2018.
Brenner, H., Braeckman, U., Le Guitton, M., and Meysman, F. J. R.: The impact
of sedimentary alkalinity release on the water column CO2 system in
the North Sea, Biogeosciences, 13, 841–863,
https://doi.org/10.5194/bg-13-841-2016, 2016.
Buch, K.: Kolsyrejämvikten i Baltiska Havet, Fennia, 68, 29–81, 1945.
Cai, W.-J., Hu, X., Huang, W.-J., Murrell, M. C., Lehrter, J. C., Lohrenz, S.
E., Chou, W.-C., Zhai, W., Hollibaugh, J. T., Wang, Y., Zhao, P., Guo, X.,
Gundersen, K., Dai, M., and Gong, G.-C.: Acidification of subsurface coastal
waters enhanced by eutrophication, Nat. Geosci., 4, 766–770,
https://doi.org/10.1038/ngeo1297, 2011.
Cai, W.-J., Huang, W.-J., Luther, G. W., Pierrot, D., Li, M., Testa, J., Xue,
M., Joesoef, A., Mann, R., Brodeur, J., Xu, Y.-Y., Chen, B., Hussain, N.,
Waldbusser, G. G., Cornwell, J., and Kemp, W. M.: Redox reactions and weak
buffering capacity lead to acidification in the Chesapeake Bay, Nat. Commun.,
8, 369, https://doi.org/10.1038/s41467-017-00417-7, 2017.
Carstensen, J., Andersen, J. H., Gustafsson, B. G., and Conley, D. J.:
Deoxygenation of the Baltic Sea during the last century, P. Natl. Acad. Sci.
USA, 111, 5628–5633, https://doi.org/10.1073/pnas.1323156111, 2014.
Chen, C.-T. A.: Shelf-vs. dissolution-generated alkalinity above the chemical
lysocline, Deep-Sea Res. Pt. II, 49, 5365–5375,
https://doi.org/10.1016/S0967-0645(02)00196-0, 2002.
Chen, C.-T. A. and Wang, S.-L.: Carbon, alkalinity and nutrient budgets on
the East China Sea continental shelf, J. Geophys. Res.-Oceans, 104,
20675–20686, https://doi.org/10.1029/1999JC900055, 1999.
Claremar, B., Wällstedt, T., Rutgersson, A., and Omstedt, A.: Deposition
of acidifying and neutralising compounds over the Baltic Sea drainage basin
between 1960 and 2006, Boreal Environ. Res., 18, 425–445, 2013.
Diaz, R. J. and Rosenberg, R.: Spreading Dead Zones and Consequences for
Marine Ecosystems, Science, 321, 926–929, https://doi.org/10.1126/science.1156401, 2008.
Dickson, A. G.: An exact definition of total alkalinity and a procedure for
the estimation of alkalinity and total inorganic carbon from titration data,
Deep-Sea Res. Pt. A, 28, 609–623, https://doi.org/10.1016/0198-0149(81)90121-7, 1981.
Dijkstra, N., Hagens, M., Egger, M., and Slomp, C. P.: Post-depositional
formation of vivianite-type minerals alters sediment phosphorus records,
Biogeosciences, 15, 861–883, https://doi.org/10.5194/bg-15-861-2018, 2018.
Dyrssen, D.: The Baltic-Kattegat-Skagerrak Estuarine System, Estuaries, 16,
446, https://doi.org/10.2307/1352592, 1993.
Egger, M., Jilbert, T., Behrends, T., Rivard, C., and Slomp, C. P.: Vivianite
is a major sink for phosphorus in methanogenic coastal surface sediments,
Geochim. Cosmochim. Ac., 169, 217–235, https://doi.org/10.1016/j.gca.2015.09.012, 2015a.
Egger, M., Rasigraf, O., Sapart, C. J., Jilbert, T., Jetten, M. S. M.,
Röckmann, T., van der Veen, C., Bândă, N., Kartal, B., Ettwig, K.
F., and Slomp, C. P.: Iron-Mediated Anaerobic Oxidation of Methane in
Brackish Coastal Sediments, Environ. Sci. Technol., 49, 277–283,
https://doi.org/10.1021/es503663z, 2015b.
Egger, M., Kraal, P., Jilbert, T., Sulu-Gambari, F., Sapart, C. J.,
Röckmann, T., and Slomp, C. P.: Anaerobic oxidation of methane alters
sediment records of sulfur, iron and phosphorus in the Black Sea,
Biogeosciences, 13, 5333–5355, https://doi.org/10.5194/bg-13-5333-2016,
2016.
Egger, M., Hagens, M., Sapart, C. J., Dijkstra, N., van Helmond, N. A. G. M.,
Mogollón, J. M., Risgaard-Petersen, N., van der Veen, C., Kasten, S.,
Riedinger, N., Böttcher, M. E., Röckmann, T., Jørgensen, B. B.,
and Slomp, C. P.: Iron oxide reduction in methane-rich deep Baltic Sea
sediments, Geochim. Cosmochim. Ac., 207, 256–276,
https://doi.org/10.1016/j.gca.2017.03.019, 2017.
Gattuso, J. P., Frankignoulle, M., and Wollast, R.: Carbon and carbonate
metabolism in coastal and aquatic ecosystems, Annu. Rev. Ecol. Syst., 29,
405–434, 1998.
Gripenberg, S.: On the alkalinity of Baltic waters, Journal du Conseil
International pour l'Exploration de la Mer, 26, 5–20, 1960.
Gustafsson, B. G.: Time-dependent modeling of the Baltic entrance area. 1.
Quantification of circulation and residence times in the Kattegat and the
Straits of the Baltic sill, Estuaries, 23, 231–252, https://doi.org/10.2307/1352830,
2000.
Gustafsson, B. G.: A Time-dependent Coupled-basin Model of the Baltic Sea,
C47, Earth Sciences Centre, Göteborg University, Göteborg, 2003.
Gustafsson, B. G., Schenk, F., Blenckner, T., Eilola, K., Meier, H. E. M.,
Müller-Karulis, B., Neumann, T., Ruoho-Airola, T., Savchuk, O. P., and
Zorita, E.: Reconstructing the Development of Baltic Sea Eutrophication
1850–2006, AMBIO, 41, 534–548, https://doi.org/10.1007/s13280-012-0318-x, 2012.
Gustafsson, E., Deutsch, B., Gustafsson, B. G., Humborg, C., and Mörth,
C.-M.: Carbon cycling in the Baltic Sea – The fate of allochthonous organic
carbon and its impact on air–sea CO2 exchange, J. Marine Syst., 129,
289–302, https://doi.org/10.1016/j.jmarsys.2013.07.005, 2014a.
Gustafsson, E., Wällstedt, T., Humborg, C., Mörth, C.-M., and
Gustafsson, B. G.: External total alkalinity loads versus internal
generation: The influence of nonriverine alkalinity sources in the Baltic
Sea, Global Biogeochem. Cy., 28, 1358–1370, https://doi.org/10.1002/2014GB004888, 2014b.
Gustafsson, E., Omstedt, A., and Gustafsson, B. G.: The air-water CO2
exchange of a coastal sea – A sensitivity study on factors that influence
the absorption and outgassing of CO2 in the Baltic Sea, J. Geophys.
Res.-Oceans, 120, 5342–5357, https://doi.org/10.1002/2015JC010832, 2015.
Gustafsson, E., Savchuk, O. P., Gustafsson, B. G., and Müller-Karulis,
B.: Key processes in the coupled carbon, nitrogen, and phosphorus cycling of
the Baltic Sea, Biogeochemistry, 134, 301–317,
https://doi.org/10.1007/s10533-017-0361-6, 2017.
Hagens, M., Hunter, K. A., Liss, P. S., and Middelburg, J. J.: Biogeochemical
context impacts seawater pH changes resulting from atmospheric sulfur and
nitrogen deposition, Geophys. Res. Lett., 41, 935–941,
https://doi.org/10.1002/2013GL058796, 2014.
Hagens, M., Slomp, C. P., Meysman, F. J. R., Seitaj, D., Harlay, J., Borges,
A. V., and Middelburg, J. J.: Biogeochemical processes and buffering capacity
concurrently affect acidification in a seasonally hypoxic coastal marine
basin, Biogeosciences, 12, 1561–1583,
https://doi.org/10.5194/bg-12-1561-2015, 2015.
Hassellöv, I.-M., Turner, D. R., Lauer, A., and Corbett, J. J.: Shipping
contributes to ocean acidification, Geophys. Res. Lett., 40, 2731–2736,
https://doi.org/10.1002/grl.50521, 2013.
Hofmann, A. F., Meysman, F. J. R., Soetaert, K., and Middelburg, J. J.: A
step-by-step procedure for pH model construction in aquatic systems,
Biogeosciences, 5, 227–251, https://doi.org/10.5194/bg-5-227-2008, 2008.
Hu, X. and Cai, W.-J.: An assessment of ocean margin anaerobic processes on
oceanic alkalinity budget, Global Biogeochem. Cy., 25, GB3003,
https://doi.org/10.1029/2010GB003859, 2011a.
Hu, X. and Cai, W.-J.: The impact of denitrification on the atmospheric
CO2 uptake potential of seawater, Mar. Chem., 127, 192–198,
https://doi.org/10.1016/j.marchem.2011.09.008, 2011b.
Jilbert, T. and Slomp, C. P.: Iron and manganese shuttles control the
formation of authigenic phosphorus minerals in the euxinic basins of the
Baltic Sea, Geochim. Cosmochim. Ac., 107, 155–169,
https://doi.org/10.1016/j.gca.2013.01.005, 2013.
Jilbert, T., Slomp, C. P., Gustafsson, B. G., and Boer, W.: (Table B1)
Geochemistry of Baltic Sea sediments, PANGAEA, https://doi.org/10.1594/PANGAEA.775277,
2011.
Jilbert, T., Slomp, C. P., Gustafsson, B. G., and Boer, W.: (Table A1)
Geochemistry of Baltic Sea porewater samples and bottom water oxygen
concentrations, PANGAEA, https://doi.org/10.1594/PANGAEA.775278, 2012.
Jørgensen, B. B.: The Sulfur Cycle of a Coastal Marine Sediment
(Limfjorden, Denmark), Limnol. Oceanogr., 22, 814–832, 1977.
Krumins, V., Gehlen, M., Arndt, S., Van Cappellen, P., and Regnier, P.:
Dissolved inorganic carbon and alkalinity fluxes from coastal marine
sediments: model estimates for different shelf environments and sensitivity
to global change, Biogeosciences, 10, 371–398,
https://doi.org/10.5194/bg-10-371-2013, 2013.
Kuliński, K., Schneider, B., Hammer, K., Machulik, U., and Schulz-Bull,
D.: The influence of dissolved organic matter on the acid–base system of the
Baltic Sea, J. Marine Syst., 132, 106–115,
https://doi.org/10.1016/j.jmarsys.2014.01.011, 2014.
Laurent, A., Fennel, K., Ko, D. S., and Lehrter, J.: Climate Change Projected
to Exacerbate Impacts of Coastal Eutrophication in the Northern Gulf of
Mexico, J. Geophys. Res.-Oceans, 123, 3408–3426, https://doi.org/10.1002/2017JC013583,
2018.
Lenz, C., Jilbert, T., Conley, D. J., and Slomp, C. P.: Hypoxia-driven
variations in iron and manganese shuttling in the Baltic Sea over the past
8 kyr, Geochem. Geophy. Geosy., 16, 3754–3766, https://doi.org/10.1002/2015GC005960,
2015a.
Lenz, C., Jilbert, T., Conley, D. J., Wolthers, M., and Slomp, C. P.: Are
recent changes in sediment manganese sequestration in the euxinic basins of
the Baltic Sea linked to the expansion of hypoxia?, Biogeosciences, 12,
4875–4894, https://doi.org/10.5194/bg-12-4875-2015, 2015b.
Lenz, C., Jilbert, T., Conley, D. J., and Slomp, C. P.: Total organic carbon
and selecetd elements of sediment core F80-A, PANGAEA,
https://doi.org/10.1594/PANGAEA.854127, 2015c.
Lepland, A. and Stevens, R. L.: Manganese authigenesis in the Landsort Deep,
Baltic Sea, Mar. Geol., 151, 1–25, https://doi.org/10.1016/S0025-3227(98)00046-2, 1998.
Łukawska-Matuszewska, K.: Contribution of non-carbonate inorganic and
organic alkalinity to total measured alkalinity in pore waters in marine
sediments (Gulf of Gdansk, S-E Baltic Sea), Mar. Chem., 186, 211–220,
https://doi.org/10.1016/j.marchem.2016.10.002, 2016.
Łukawska-Matuszewska, K. and Graca, B.: Pore water alkalinity below the
permanent halocline in the Gdańsk Deep (Baltic Sea) – Concentration
variability and benthic fluxes, Mar. Chem., 204, 49–61,
https://doi.org/10.1016/j.marchem.2018.05.011, 2018.
Łukawska-Matuszewska, K., Grzybowski, W., Szewczun, A., and Tarasiewicz,
P.: Constituents of organic alkalinity in pore water of marine sediments,
Mar. Chem., 200, 22–32, https://doi.org/10.1016/j.marchem.2018.01.012, 2018.
Middelburg, J. J. and Levin, L. A.: Coastal hypoxia and sediment
biogeochemistry, Biogeosciences, 6, 1273–1293,
https://doi.org/10.5194/bg-6-1273-2009, 2009.
Millero, F. J., Sotolongo, S., and Izaguirre, M.: The oxidation kinetics of
Fe(II) in seawater, Geochim. Cosmochim. Ac., 51, 793–801,
https://doi.org/10.1016/0016-7037(87)90093-7, 1987.
Müller, J. D., Schneider, B., and Rehder, G.: Long-term alkalinity trends
in the Baltic Sea and their implications for CO2-induced
acidification, Limnol. Oceanogr., 61, 1984–2002, https://doi.org/10.1002/lno.10349,
2016.
Ohlson, M. and Anderson, L.: Recent investigation of total carbonate in the
Baltic Sea: changes from the past as a result of acid rain?, Mar. Chem., 30,
259–267, https://doi.org/10.1016/0304-4203(90)90075-N, 1990.
Omstedt, A., Edman, M., Claremar, Bj., Frodin, P., Gustafsson, E., Humborg,
C., Hägg, H., Mörth, M., Rutgersson, A., Schurgers, G., Smith, B.,
Wällstedt, T., and Yurova, A.: Future changes in the Baltic Sea
acid–base (pH) and oxygen balances, Tellus B, 64, 19586,
https://doi.org/10.3402/tellusb.v64i0.19586, 2012.
Omstedt, A., Edman, M., Claremar, B., and Rutgersson, A.: Modelling the
contributions to marine acidification from deposited SOx,
NOx, and NHx in the Baltic Sea: Past and
present situations, Cont. Shelf Res., 111, 234–249,
https://doi.org/10.1016/j.csr.2015.08.024, 2015.
Perttilä, M., Terrihauta, S., Lemponen, P., Riikonen, J., Grau Garcia,
M., Hernández Abós, E., and Rodriquez Moles, J.:
Alkalinity–calcium–salinity relations in the Baltic Sea 1. Data description
and general considerations, Meri: Report Series of the Finnish Institute of
Marine Research, Finnish Institute of Marine Research, 2006.
Rabalais, N. N., Cai, W.-J., Carstensen, J., Conley, D. J., Fry, B., Hu, X.,
Quiñones-Rivera, Z., Rosenberg, R., Slomp, C. P., Turner, R. E., Voss,
M., Wissel, B., and Zhang, J.: Eutrophication-Driven Deoxygenation in the
Coastal Ocean, Oceanography, 27, 172–183, 2014.
Raiswell, R. and Canfield, D. E.: The Iron Biogeochemical Cycle Past and
Present, Geochem. Perspect., 1, 1–2, 2012.
Reed, D. C., Gustafsson, B. G., and Slomp, C. P.: Shelf-to-basin iron
shuttling enhances vivianite formation in deep Baltic Sea sediments, Earth
Planet. Sc. Lett., 434, 241–251, https://doi.org/10.1016/j.epsl.2015.11.033,
2016.
Regnier, P., Friedlingstein, P., Ciais, P., Mackenzie, F. T., Gruber, N.,
Janssens, I. A., Laruelle, G. G., Lauerwald, R., Luyssaert, S., Andersson, A.
J., Arndt, S., Arnosti, C., Borges, A. V., Dale, A. W., Gallego-Sala, A.,
Goddéris, Y., Goossens, N., Hartmann, J., Heinze, C., Ilyina, T., Joos,
F., LaRowe, D. E., Leifeld, J., Meysman, F. J. R., Munhoven, G., Raymond, P.
A., Spahni, R., Suntharalingam, P., and Thullner, M.: Anthropogenic
perturbation of the carbon fluxes from land to ocean, Nat. Geosci., 6,
597–607, https://doi.org/10.1038/ngeo1830, 2013.
Riedinger, N., Formolo, M. J., Lyons, T. W., Henkel, S., Beck, A., and
Kasten, S.: An inorganic geochemical argument for coupled anaerobic oxidation
of methane and iron reduction in marine sediments, Geobiology, 12, 172–181,
https://doi.org/10.1111/gbi.12077, 2014.
Ruppin, E.: Die Alkalinität des Meerwassers, Wissenschaftliche
Meeresuntersuchungen Abt. Kiel, 11, 277–302, 1909.
Sarmiento, J. L. and Gruber, N.: Ocean Biogeochemical Dynamics, Princeton
University Press, Princeton, NJ, 2006.
Savchuk, O. P., Gustafsson, B. G., and Müller-Karulis, B.: BALTSEM – a
marine model for the decision support within the Baltic Sea Region, Technical
Report No. 7, Baltic Nest Institute, Stockholm University, 2012.
Slomp, C. P., Mort, H. P., Jilbert, T., Reed, D. C., Gustafsson, B. G., and
Wolthers, M.: Coupled Dynamics of Iron and Phosphorus in Sediments of an
Oligotrophic Coastal Basin and the Impact of Anaerobic Oxidation of Methane,
PLOS ONE, 8, e62386, https://doi.org/10.1371/journal.pone.0062386, 2013.
Soetaert, K., Hofmann, A. F., Middelburg, J. J., Meysman, F. J. R., and
Greenwood, J.: The effect of biogeochemical processes on pH, Mar. Chem., 105,
30–51, https://doi.org/10.1016/j.marchem.2006.12.012, 2007.
Stigebrandt, A. and Gustafsson, B. G.: Improvement of Baltic Proper Water
Quality Using Large-scale Ecological Engineering, AMBIO, 36, 280–286,
https://doi.org/10.1579/0044-7447(2007)36[280:IOBPWQ]2.0.CO;2, 2007.
Sun, X., Mörth, C.-M., Humborg, C., and Gustafsson, B.: Temporal and
spatial variations of rock weathering and CO2 consumption in the
Baltic Sea catchment, Chem. Geol., 466, 57–69,
https://doi.org/10.1016/j.chemgeo.2017.04.028, 2017.
Szymczycha, B., Maciejewska, A., Winogradow, A., and Pempkowiak, J.: Could
submarine groundwater discharge be a significant carbon source to the
southern Baltic Sea?, Oceanologia, 56, 327–347, https://doi.org/10.5697/oc.56-2.327,
2014.
Thomas, H. and Schneider, B.: The seasonal cycle of carbon dioxide in Baltic
Sea surface waters, J. Marine Syst., 22, 53–67,
https://doi.org/10.1016/S0924-7963(99)00030-5, 1999.
Thomas, H., Schiettecatte, L.-S., Suykens, K., Koné, Y. J. M., Shadwick,
E. H., Prowe, A. E. F., Bozec, Y., de Baar, H. J. W., and Borges, A. V.:
Enhanced ocean carbon storage from anaerobic alkalinity generation in coastal
sediments, Biogeosciences, 6, 267–274,
https://doi.org/10.5194/bg-6-267-2009, 2009.
Tyrrell, T., Schneider, B., Charalampopoulou, A., and Riebesell, U.:
Coccolithophores and calcite saturation state in the Baltic and Black Seas,
Biogeosciences, 5, 485–494, https://doi.org/10.5194/bg-5-485-2008, 2008.
Ulfsbo, A., Hulth, S., and Anderson, L. G.: pH and biogeochemical processes
in the Gotland Basin of the Baltic Sea, Mar. Chem., 127, 20–30,
https://doi.org/10.1016/j.marchem.2011.07.004, 2011.
Ulfsbo, A., Kuliński, K., Anderson, L. G., and Turner, D. R.: Modelling
organic alkalinity in the Baltic Sea using a Humic-Pitzer approach, Mar.
Chem., 168, 18–26, https://doi.org/10.1016/j.marchem.2014.10.013, 2015.
van Heuven, S., Pierrot, D., Rae, J. W. B., Lewis, E., and Wallace, D. W. R.:
MATLAB Program Developed for CO2 System Calculations,
ORNL/CDIAC-105b, Carbon Dioxide Information Analysis Center, Oak Ridge
National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee,
https://doi.org/10.3334/CDIAC/otg.CO2SYS_MATLAB_v1.1, 2011.
Wallmann, K., Aloisi, G., Haeckel, M., Tishchenko, P., Pavlova, G., Greinert,
J., Kutterolf, S., and Eisenhauer, A.: Silicate weathering in anoxic marine
sediments, Geochim. Cosmochim. Ac., 72, 2895–2918,
https://doi.org/10.1016/j.gca.2008.03.026, 2008.
Wang, Y. and Van Cappellen, P.: A multicomponent reactive transport
model of
early diagenesis: Application to redox cycling in coastal marine sediments,
Geochim. Cosmochim. Ac., 60, 2993–3014, https://doi.org/10.1016/0016-7037(96)00140-8,
1996.
Wolf-Gladrow, D. A., Zeebe, R. E., Klaas, C., Körtzinger, A., and
Dickson, A. G.: Total alkalinity: The explicit conservative expression and
its application to biogeochemical processes, Mar. Chem., 106, 287–300,
https://doi.org/10.1016/j.marchem.2007.01.006, 2007.
Download
The requested paper has a corresponding corrigendum published. Please read the corrigendum first before downloading the article.
- Article
(3235 KB) - Full-text XML
- Corrigendum
-
Supplement
(888 KB) - BibTeX
- EndNote
Short summary
This work highlights that iron (Fe) dynamics plays a key role in the release of alkalinity from sediments, as exemplified for the Baltic Sea. It furthermore demonstrates that burial of Fe sulfides should be included in alkalinity budgets of low-oxygen basins. The sedimentary alkalinity generation may undergo large changes depending on both organic matter loads and oxygen conditions. Enhanced release of alkalinity from the seafloor can increase the CO2 storage capacity of seawater.
This work highlights that iron (Fe) dynamics plays a key role in the release of alkalinity from...
Altmetrics
Final-revised paper
Preprint