Articles | Volume 21, issue 20
https://doi.org/10.5194/bg-21-4495-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-21-4495-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
15 Oct 2024
Research article |
| 15 Oct 2024
| 15 Oct 2024
Seasonal dynamics and regional distribution patterns of CO2 and CH4 in the north-eastern Baltic Sea
Silvie Lainela
CORRESPONDING AUTHOR
Department of Marine Systems, Tallinn University of Technology, Tallinn, 12618, Estonia
Erik Jacobs
Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, 18119, Germany
Stella-Theresa Luik
Department of Marine Systems, Tallinn University of Technology, Tallinn, 12618, Estonia
previously published under the name Stella-Theresa Stoicescu
Gregor Rehder
Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, 18119, Germany
Urmas Lips
Department of Marine Systems, Tallinn University of Technology, Tallinn, 12618, Estonia
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Florian Börgel, Itzel Ruvalcaba Baroni, Leonie Barghorn, Leonard Borchert, Bronwyn Cahill, Cyril Dutheil, Leonie Esters, Malgorzata Falarz, Helena L. Filipsson, Matthias Gröger, Jari Hänninen, Magnus Hieronymus, Erko Jakobsen, Mehdi Pasha Karami, Karol Kulinski, Taavi Liblik, H. E. Markus Meier, Gabriele Messori, Lev Naumov, Thomas Neumann, Piia Post, Gregor Rehder, Anna Rutgersson, and Georg Sebastian Voelker
EGUsphere, https://doi.org/10.5194/egusphere-2025-5496, https://doi.org/10.5194/egusphere-2025-5496, 2025
This preprint is open for discussion and under review for Earth System Dynamics (ESD).
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This review explains how weather patterns, guided by the polar jet stream, influence the Baltic Sea’s climate and ecosystem. It covers the NAO, blocking events and other processes and discusses how they affect temperature, rainfall, and storms from days to decades. These shifts then impact oxygen levels, productivity, and acidification in the Baltic Sea. Physical links are fairly well known, but biogeochemical pathways remain uncertain.
Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Dorothee C. E. Bakker, Judith Hauck, Peter Landschützer, Corinne Le Quéré, Hongmei Li, Ingrid T. Luijkx, Glen P. Peters, Wouter Peters, Julia Pongratz, Clemens Schwingshackl, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Kjetil Aas, Simone R. Alin, Peter Anthoni, Leticia Barbero, Nicholas R. Bates, Nicolas Bellouin, Alice Benoit-Cattin, Carla F. Berghoff, Raffaele Bernardello, Laurent Bopp, Ida B. M. Brasika, Matthew A. Chamberlain, Naveen Chandra, Frédéric Chevallier, Louise P. Chini, Nathan O. Collier, Thomas H. Colligan, Margot Cronin, Laique Djeutchouang, Xinyu Dou, Matt P. Enright, Kazutaka Enyo, Michael Erb, Wiley Evans, Richard A. Feely, Liang Feng, Daniel J. Ford, Adrianna Foster, Filippa Fransner, Thomas Gasser, Marion Gehlen, Thanos Gkritzalis, Jefferson Goncalves De Souza, Giacomo Grassi, Luke Gregor, Nicolas Gruber, Bertrand Guenet, Özgür Gürses, Kirsty Harrington, Ian Harris, Jens Heinke, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Akihiko Ito, Andrew R. Jacobson, Atul K. Jain, Tereza Jarníková, Annika Jersild, Fei Jiang, Steve D. Jones, Etsushi Kato, Ralph F. Keeling, Kees Klein Goldewijk, Jürgen Knauer, Yawen Kong, Jan Ivar Korsbakken, Charles Koven, Taro Kunimitsu, Xin Lan, Junjie Liu, Zhiqiang Liu, Zhu Liu, Claire Lo Monaco, Lei Ma, Gregg Marland, Patrick C. McGuire, Galen A. McKinley, Joe Melton, Natalie Monacci, Erwan Monier, Eric J. Morgan, David R. Munro, Jens D. Müller, Shin-Ichiro Nakaoka, Lorna R. Nayagam, Yosuke Niwa, Tobias Nutzel, Are Olsen, Abdirahman M. Omar, Naiqing Pan, Sudhanshu Pandey, Denis Pierrot, Zhangcai Qin, Pierre A. G. Regnier, Gregor Rehder, Laure Resplandy, Alizée Roobaert, Thais M. Rosan, Christian Rödenbeck, Jörg Schwinger, Ingunn Skjelvan, T. Luke Smallman, Victoria Spada, Mohanan G. Sreeush, Qing Sun, Adrienne J. Sutton, Colm Sweeney, Didier Swingedouw, Roland Séférian, Shintaro Takao, Hiroaki Tatebe, Hanqin Tian, Xiangjun Tian, Bronte Tilbrook, Hiroyuki Tsujino, Francesco Tubiello, Erik van Ooijen, Guido van der Werf, Sebastiaan J. van de Velde, Anthony Walker, Rik Wanninkhof, Xiaojuan Yang, Wenping Yuan, Xu Yue, and Jiye Zeng
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-659, https://doi.org/10.5194/essd-2025-659, 2025
Preprint under review for ESSD
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The Global Carbon Budget 2025 describes the methodology, main results, and datasets used to quantify the anthropogenic emissions of carbon dioxide (CO2) and their partitioning among the atmosphere, land ecosystems, and the ocean over the historical period (1750–2025). These living datasets are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Kai Salm, Germo Väli, Taavi Liblik, and Urmas Lips
Ocean Sci., 21, 2555–2577, https://doi.org/10.5194/os-21-2555-2025, https://doi.org/10.5194/os-21-2555-2025, 2025
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We show that the presence of submesoscale processes depends on atmospheric forcing and is evident in both glider observations and high-resolution numerical simulations. Peak submesoscale variability was found near the base of the upper mixed layer in spring and within the thermocline in summer. Coastal upwelling and topographically induced frontal instabilities likely drove subduction and the downward transport of surface waters and tracers.
Daniel L. Pönisch, Henry C. Bittig, Martin Kolbe, Ingo Schuffenhauer, Stefan Otto, Peter Holtermann, Kusala Premaratne, and Gregor Rehder
Biogeosciences, 22, 3583–3614, https://doi.org/10.5194/bg-22-3583-2025, https://doi.org/10.5194/bg-22-3583-2025, 2025
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Rewetted peatlands exhibit natural spatiotemporal biogeochemical heterogeneity, influenced by water level and vegetation. This study investigated the variability of greenhouse gas distribution in a peatland rewetted with brackish water. Two innovative sensor-equipped platforms were used to measure a wide range of marine physicochemical variables at high temporal resolution. The measurements revealed strong fluctuations in CO2 and CH4, expressed as multi-day, diurnal, and event-based variability.
Pratirupa Bardhan, Claudia Frey, Gregor Rehder, and Hermann W. Bange
EGUsphere, https://doi.org/10.5194/egusphere-2025-2518, https://doi.org/10.5194/egusphere-2025-2518, 2025
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Nitrous oxide (N2O), a potent greenhouse gas, is released from coastal seas & estuaries, yet we don't fully understand how it is formed and consumed. In this study we collected water from several sites in the central Baltic Sea. N2O came from ammonia in oxic waters. Deep waters with low to no oxygen noted more active N2O cycling. The seafloor was a source in some areas. Typically N2O is produced by bacteria, but our results indicate possibility of other players like fungi or chemical reactions.
Taavi Liblik, Daniel Rak, Enriko Siht, Germo Väli, Johannes Karstensen, Laura Tuomi, Louise C. Biddle, Madis-Jaak Lilover, Māris Skudra, Michael Naumann, Urmas Lips, and Volker Mohrholz
EGUsphere, https://doi.org/10.5194/egusphere-2024-2272, https://doi.org/10.5194/egusphere-2024-2272, 2024
Preprint archived
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Eight current meters were deployed to the seafloor across the Baltic to enhance knowledge about circulation and currents. The experiment was complemented by autonomous vehicles. Stable circulation patterns were observed at the sea when weather was steady. Strong and quite persistent currents were observed at the key passage for the deep-water renewal of the Northern Baltic Sea. Deep water renewal mostly occurs during spring and summer periods in the northern Baltic Sea.
Henry C. Bittig, Erik Jacobs, Thomas Neumann, and Gregor Rehder
Earth Syst. Sci. Data, 16, 753–773, https://doi.org/10.5194/essd-16-753-2024, https://doi.org/10.5194/essd-16-753-2024, 2024
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We present a pCO2 climatology of the Baltic Sea using a new approach to extrapolate from individual observations to the entire Baltic Sea. The extrapolation approach uses (a) a model to inform on how data at one location are connected to data at other locations, together with (b) very accurate pCO2 observations from 2003 to 2021 as the base data. The climatology can be used e.g. to assess uptake and release of CO2 or to identify extreme events.
Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Dorothee C. E. Bakker, Judith Hauck, Peter Landschützer, Corinne Le Quéré, Ingrid T. Luijkx, Glen P. Peters, Wouter Peters, Julia Pongratz, Clemens Schwingshackl, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Robert B. Jackson, Simone R. Alin, Peter Anthoni, Leticia Barbero, Nicholas R. Bates, Meike Becker, Nicolas Bellouin, Bertrand Decharme, Laurent Bopp, Ida Bagus Mandhara Brasika, Patricia Cadule, Matthew A. Chamberlain, Naveen Chandra, Thi-Tuyet-Trang Chau, Frédéric Chevallier, Louise P. Chini, Margot Cronin, Xinyu Dou, Kazutaka Enyo, Wiley Evans, Stefanie Falk, Richard A. Feely, Liang Feng, Daniel J. Ford, Thomas Gasser, Josefine Ghattas, Thanos Gkritzalis, Giacomo Grassi, Luke Gregor, Nicolas Gruber, Özgür Gürses, Ian Harris, Matthew Hefner, Jens Heinke, Richard A. Houghton, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Andrew R. Jacobson, Atul Jain, Tereza Jarníková, Annika Jersild, Fei Jiang, Zhe Jin, Fortunat Joos, Etsushi Kato, Ralph F. Keeling, Daniel Kennedy, Kees Klein Goldewijk, Jürgen Knauer, Jan Ivar Korsbakken, Arne Körtzinger, Xin Lan, Nathalie Lefèvre, Hongmei Li, Junjie Liu, Zhiqiang Liu, Lei Ma, Greg Marland, Nicolas Mayot, Patrick C. McGuire, Galen A. McKinley, Gesa Meyer, Eric J. Morgan, David R. Munro, Shin-Ichiro Nakaoka, Yosuke Niwa, Kevin M. O'Brien, Are Olsen, Abdirahman M. Omar, Tsuneo Ono, Melf Paulsen, Denis Pierrot, Katie Pocock, Benjamin Poulter, Carter M. Powis, Gregor Rehder, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Thais M. Rosan, Jörg Schwinger, Roland Séférian, T. Luke Smallman, Stephen M. Smith, Reinel Sospedra-Alfonso, Qing Sun, Adrienne J. Sutton, Colm Sweeney, Shintaro Takao, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Hiroyuki Tsujino, Francesco Tubiello, Guido R. van der Werf, Erik van Ooijen, Rik Wanninkhof, Michio Watanabe, Cathy Wimart-Rousseau, Dongxu Yang, Xiaojuan Yang, Wenping Yuan, Xu Yue, Sönke Zaehle, Jiye Zeng, and Bo Zheng
Earth Syst. Sci. Data, 15, 5301–5369, https://doi.org/10.5194/essd-15-5301-2023, https://doi.org/10.5194/essd-15-5301-2023, 2023
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The Global Carbon Budget 2023 describes the methodology, main results, and data sets used to quantify the anthropogenic emissions of carbon dioxide (CO2) and their partitioning among the atmosphere, land ecosystems, and the ocean over the historical period (1750–2023). These living datasets are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Daniel L. Pönisch, Anne Breznikar, Cordula N. Gutekunst, Gerald Jurasinski, Maren Voss, and Gregor Rehder
Biogeosciences, 20, 295–323, https://doi.org/10.5194/bg-20-295-2023, https://doi.org/10.5194/bg-20-295-2023, 2023
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Peatland rewetting is known to reduce dissolved nutrients and greenhouse gases; however, short-term nutrient leaching and high CH4 emissions shortly after rewetting are likely to occur. We investigated the rewetting of a coastal peatland with brackish water and its effects on nutrient release and greenhouse gas fluxes. Nutrient concentrations were higher in the peatland than in the adjacent bay, leading to an export. CH4 emissions did not increase, which is in contrast to freshwater rewetting.
Thomas Neumann, Hagen Radtke, Bronwyn Cahill, Martin Schmidt, and Gregor Rehder
Geosci. Model Dev., 15, 8473–8540, https://doi.org/10.5194/gmd-15-8473-2022, https://doi.org/10.5194/gmd-15-8473-2022, 2022
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Marine ecosystem models are usually constrained by the elements nitrogen and phosphorus and consider carbon in organic matter in a fixed ratio. Recent observations show a substantial deviation from the simulated carbon cycle variables. In this study, we present a marine ecosystem model for the Baltic Sea which allows for a flexible uptake ratio for carbon, nitrogen, and phosphorus. With this extension, the model reflects much more reasonable variables of the marine carbon cycle.
Stella-Theresa Stoicescu, Jaan Laanemets, Taavi Liblik, Māris Skudra, Oliver Samlas, Inga Lips, and Urmas Lips
Biogeosciences, 19, 2903–2920, https://doi.org/10.5194/bg-19-2903-2022, https://doi.org/10.5194/bg-19-2903-2022, 2022
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Coastal basins with high input of nutrients often suffer from oxygen deficiency. In summer 2018, the extent of oxygen depletion was exceptional in the Gulf of Riga. We analyzed observational data and found that extensive oxygen deficiency appeared since the water layer close to the seabed, where oxygen is consumed, was separated from the surface layer. The problem worsens if similar conditions restricting vertical transport of oxygen occur more frequently in the future.
Taavi Liblik, Germo Väli, Kai Salm, Jaan Laanemets, Madis-Jaak Lilover, and Urmas Lips
Ocean Sci., 18, 857–879, https://doi.org/10.5194/os-18-857-2022, https://doi.org/10.5194/os-18-857-2022, 2022
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An extensive measurement campaign and numerical simulations were conducted in the central Baltic Sea. The persistent circulation patterns were detected in steady weather conditions. The patterns included various circulation features. A coastal boundary current was observed along the eastern coast. The deep layer current towards the north was detected as well. This current is an important deeper limb of the overturning circulation of the Baltic Sea. The circulation regime has an annual cycle.
Pierre Friedlingstein, Matthew W. Jones, Michael O'Sullivan, Robbie M. Andrew, Dorothee C. E. Bakker, Judith Hauck, Corinne Le Quéré, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Rob B. Jackson, Simone R. Alin, Peter Anthoni, Nicholas R. Bates, Meike Becker, Nicolas Bellouin, Laurent Bopp, Thi Tuyet Trang Chau, Frédéric Chevallier, Louise P. Chini, Margot Cronin, Kim I. Currie, Bertrand Decharme, Laique M. Djeutchouang, Xinyu Dou, Wiley Evans, Richard A. Feely, Liang Feng, Thomas Gasser, Dennis Gilfillan, Thanos Gkritzalis, Giacomo Grassi, Luke Gregor, Nicolas Gruber, Özgür Gürses, Ian Harris, Richard A. Houghton, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Ingrid T. Luijkx, Atul Jain, Steve D. Jones, Etsushi Kato, Daniel Kennedy, Kees Klein Goldewijk, Jürgen Knauer, Jan Ivar Korsbakken, Arne Körtzinger, Peter Landschützer, Siv K. Lauvset, Nathalie Lefèvre, Sebastian Lienert, Junjie Liu, Gregg Marland, Patrick C. McGuire, Joe R. Melton, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Tsuneo Ono, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Thais M. Rosan, Jörg Schwinger, Clemens Schwingshackl, Roland Séférian, Adrienne J. Sutton, Colm Sweeney, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Francesco Tubiello, Guido R. van der Werf, Nicolas Vuichard, Chisato Wada, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Chao Yue, Xu Yue, Sönke Zaehle, and Jiye Zeng
Earth Syst. Sci. Data, 14, 1917–2005, https://doi.org/10.5194/essd-14-1917-2022, https://doi.org/10.5194/essd-14-1917-2022, 2022
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The Global Carbon Budget 2021 describes the data sets and methodology used to quantify the emissions of carbon dioxide and their partitioning among the atmosphere, land, and ocean. These living data are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
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
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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.
Andreas Lehmann, Kai Myrberg, Piia Post, Irina Chubarenko, Inga Dailidiene, Hans-Harald Hinrichsen, Karin Hüssy, Taavi Liblik, H. E. Markus Meier, Urmas Lips, and Tatiana Bukanova
Earth Syst. Dynam., 13, 373–392, https://doi.org/10.5194/esd-13-373-2022, https://doi.org/10.5194/esd-13-373-2022, 2022
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The salinity in the Baltic Sea is not only an important topic for physical oceanography as such, but it also integrates the complete water and energy cycle. It is a primary external driver controlling ecosystem dynamics of the Baltic Sea. The long-term dynamics are controlled by river runoff, net precipitation, and the water mass exchange between the North Sea and Baltic Sea. On shorter timescales, the ephemeral atmospheric conditions drive a very complex and highly variable salinity regime.
Martti Honkanen, Jens Daniel Müller, Jukka Seppälä, Gregor Rehder, Sami Kielosto, Pasi Ylöstalo, Timo Mäkelä, Juha Hatakka, and Lauri Laakso
Ocean Sci., 17, 1657–1675, https://doi.org/10.5194/os-17-1657-2021, https://doi.org/10.5194/os-17-1657-2021, 2021
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The exchange of carbon dioxide (CO2) between the sea and the atmosphere is regulated by the gradient of CO2 partial pressure (pCO2) between the sea and the air. The daily variation of the seawater pCO2 recorded at the fixed station Utö in the Baltic Sea was found to be mainly biologically driven. Calculation of the annual net exchange of CO2 between the sea and atmosphere based on daily measurements of pCO2 carried out using the same sampling time every day could introduce a bias of up to 12 %.
Jens Daniel Müller, Bernd Schneider, Ulf Gräwe, Peer Fietzek, Marcus Bo Wallin, Anna Rutgersson, Norbert Wasmund, Siegfried Krüger, and Gregor Rehder
Biogeosciences, 18, 4889–4917, https://doi.org/10.5194/bg-18-4889-2021, https://doi.org/10.5194/bg-18-4889-2021, 2021
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Based on profiling pCO2 measurements from a field campaign, we quantify the biomass production of a cyanobacteria bloom in the Baltic Sea, the export of which would foster deep water deoxygenation. We further demonstrate how this biomass production can be accurately reconstructed from long-term surface measurements made on cargo vessels in combination with modelled temperature profiles. This approach enables a better understanding of a severe concern for the Baltic’s good environmental status.
Erik Jacobs, Henry C. Bittig, Ulf Gräwe, Carolyn A. Graves, Michael Glockzin, Jens D. Müller, Bernd Schneider, and Gregor Rehder
Biogeosciences, 18, 2679–2709, https://doi.org/10.5194/bg-18-2679-2021, https://doi.org/10.5194/bg-18-2679-2021, 2021
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We use a unique data set of 8 years of continuous carbon dioxide (CO2) and methane (CH4) surface water measurements from a commercial ferry to study upwelling in the Baltic Sea. Its seasonality and regional and interannual variability are examined. Strong upwelling events drastically increase local surface CO2 and CH4 levels and are mostly detected in late summer after long periods of impaired mixing. We introduce an extrapolation method to estimate regional upwelling-induced trace gas fluxes.
Trystan Sanders, Jörn Thomsen, Jens Daniel Müller, Gregor Rehder, and Frank Melzner
Biogeosciences, 18, 2573–2590, https://doi.org/10.5194/bg-18-2573-2021, https://doi.org/10.5194/bg-18-2573-2021, 2021
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The Baltic Sea is expected to experience a rapid drop in salinity and increases in acidity and warming in the next century. Calcifying mussels dominate Baltic Sea seafloor ecosystems yet are sensitive to changes in seawater chemistry. We combine laboratory experiments and a field study and show that a lack of calcium causes extremely slow growth rates in mussels at low salinities. Subsequently, climate change in the Baltic may have drastic ramifications for Baltic seafloor ecosystems.
Anna Rose Canning, Peer Fietzek, Gregor Rehder, and Arne Körtzinger
Biogeosciences, 18, 1351–1373, https://doi.org/10.5194/bg-18-1351-2021, https://doi.org/10.5194/bg-18-1351-2021, 2021
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The paper describes a novel, fully autonomous, multi-gas flow-through set-up for multiple gases that combines established, high-quality oceanographic sensors in a small and robust system designed for use across all salinities and all types of platforms. We describe the system and its performance in all relevant detail, including the corrections which improve the accuracy of these sensors, and illustrate how simultaneous multi-gas set-ups can provide an extremely high spatiotemporal resolution.
Meike Becker, Are Olsen, Peter Landschützer, Abdirhaman Omar, Gregor Rehder, Christian Rödenbeck, and Ingunn Skjelvan
Biogeosciences, 18, 1127–1147, https://doi.org/10.5194/bg-18-1127-2021, https://doi.org/10.5194/bg-18-1127-2021, 2021
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We developed a simple method to refine existing open-ocean maps towards different coastal seas. Using a multi-linear regression, we produced monthly maps of surface ocean fCO2 in the northern European coastal seas (the North Sea, the Baltic Sea, the Norwegian Coast and the Barents Sea) covering a time period from 1998 to 2016. Based on this fCO2 map, we calculate trends in surface ocean fCO2, pH and the air–sea gas exchange.
Cited articles
Alenius, P., Myrberg, K., and Nekrasov, A.: The physical oceanography of the Gulf of Finland: a review, Boreal Environ. Res., 3, 97–125, 1998.
Alenius, P., Nekrasov, A., and Myrberg, K.: Variability of the baroclinic Rossby radius in the Gulf of Finland, Cont. Shelf Res., 23, 563–573, https://doi.org/10.1016/S0278-4343(03)00004-9, 2003.
Andrejev, O., Myrberg, K., Alenius, P., and Lundberg, P.A.: Mean circulation and water exchange in the Gulf of Finland e a study based on three-dimensional modelling, Boreal. Environ. Res., 9, 1–16, 2004.
Astok, V., Otsmann, M., and Suursaar, Ü.: Water exchange as the main physical process in semi-enclosed marine systems: the Gulf of Riga case, Hydrobiologia, 393, 11–18, https://doi.org/10.1023/A:1003517110726, 1999.
Bange, H. W., Bartell, U. H., Rapsomanikis, S., and Andreae, M. O.: Methane in the Baltic and North Seas and a reassessment of the marine emissions of methane, Global Biogeochem. Cy., 8, 465–480, https://doi.org/10.1029/94GB02181, 1994.
Borges, A. V., Champenois, W., Gypens, N., Delille, B., and Harlay, J.: Massive marine methane emissions from near-shore shallow coastal areas, Sci. Rep.-UK, 6, 27908, https://doi.org/10.1038/srep27908, 2016.
Borges, A. V., Speeckaert, G., Champenois, W., Scranton, M. I., and Gypens, N.: Productivity and Temperature as Drivers of Seasonal and Spatial Variations of Dissolved Methane in the Southern Bight of the North Sea, Ecosystems, 21, 583–599, https://doi.org/10.1007/s10021-017-0171-7, 2018.
Canadell, J. G., Monteiro, P. M. S., Costa, M. H., Cotrim da Cunha, L., Cox, P. M., Eliseev, A. V., Henson, S., Ishii, M., Jaccard, S., Koven, C., Lohila, A., Patra, P. K., Piao, S., Rogelj, J., Syampungani, S., Zaehle, S., and Zickfeld, K.: Global Carbon and other Biogeochemical Cycles and Feedbacks, in: Climate Change 2021 – The Physical Science Basis, Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., Cambridge University Press, 673–816, https://doi.org/10.1017/9781009157896.007, 2023.
Dai, M., Su, J., Zhao, Y., Hofmann, E.E., Cao, Z., Cai, W.-J., Gan, J., Lacroix, F., Laruelle, G. G., Meng, F., Müller, J. D., Regnier, P. A. G., Wang, G., and Wang, Z.: Carbon Fluxes in the Coastal Ocean: Synthesis, Boundary Processes, and Future Trends, Annu. Rev. Earth Pl. Sc., 50, 593–626, https://doi.org/10.1146/annurev-earth-032320-090746, 2022.
De Angelis, M. A. and Lilley, M. D.: Methane in surface waters of Oregon estuaries and rivers, Limnol. Oceanogr., 32, 716–722, https://doi.org/10.4319/lo.1987.32.3.0716, 1987.
Dlugokencky, E. J., Steele, L. P., Lang, P. M., and Masarie, K. A.: The growth rate and distribution of atmospheric methane, J. Geophys. Res., 99, 17021–17043, https://doi.org/10.1029/94JD01245, 1994.
EMODnet Geology: https://emodnet.ec.europa.eu/geoviewer/?layers=12494:1:1&basemap=ebwbl&active=12494&bounds=1889347.1962289177,7790646.9624039605,3305342.315828531,8401847.980824888&filters=&projection=EPSG:3857, last access: 25 August 2023.
Gustafsson, E., Carstensen, J., Fleming, V., Gustafsson, B. G., Hoikkala, L., and Rehder, G.: Causes and consequences of acidification in the Baltic Sea: implications for monitoring and management, Sci. Rep.-UK, 13, 16322, https://doi.org/10.1038/s41598-023-43596-8, 2023.
Gutiérrez-Loza, L., Wallin, M. B., Sahlée, E., Holding, T., Shutler, J. D., Rehder, G., and Rutgersson, A.: Air–sea CO2 exchange in the Baltic Sea–A sensitivity analysis of the gas transfer velocity, J. Marine Syst., 222, 103603, https://doi.org/10.1016/j.jmarsys.2021.103603, 2021.
Gülzow, W., Rehder, G., Schneider, B., Schneider von Deimling, J., and Sadkowiak, B.: A new method for continuous measurement of methane and carbon dioxide in surface waters using off-axis integrated cavity output spectroscopy (ICOS): An example from the Baltic Sea, Limnol. Oceanogr.-Meth., 9, 176–184, https://doi.org/10.4319/lom.2011.9.176, 2011.
Gülzow, W., Rehder, G., Schneider v. Deimling, J., Seifert, T., and Tóth, Z.: One year of continuous measurements constraining methane emissions from the Baltic Sea to the atmosphere using a ship of opportunity, Biogeosciences, 10, 81–99, https://doi.org/10.5194/bg-10-81-2013, 2013.
Gülzow, W., Gräwe, U., Kedzior, S., Schmale, O., and Rehder, G.: Seasonal variation of methane in the water column of Arkona and Bornholm Basin, western Baltic Sea, J. Marine Syst., 139, 332–347, https://doi.org/10.1016/j.jmarsys.2014.07.013, 2014.
HELCOM: Manual for the Marine Monitoring in the COMBINE Programme of HELCOM, https://helcom.fi/action-areas/monitoring-and-assessment/monitoring-guidelines/combine-manual/ (last access: 16 June 2023), 2017.
HELCOM: HELCOM Thematic assessment of eutrophication 2011–2016. Baltic Sea Environment Proceedings No. 156, Baltic Marine Environment Protection Commission, ISSN 0357-2994, 2018.
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., and Thépaut, J.-N.: ERA5 monthly averaged data on single levels from 1979 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.f17050d7, 2019.
Heyer, J. and Berger, U.: Methane emission from the coastal area in the southern Baltic Sea, Estuar. Coast. Shelf S., 51, 13–30, https://doi.org/10.1006/ecss.2000.0616, 2000.
Holding, T., Ashton, I. G., Shutler, J. D., Land, P. E., Nightingale, P. D., Rees, A. P., Brown, I., Piolle, J.-F., Kock, A., Bange, H. W., Woolf, D. K., Goddijn-Murphy, L., Pereira, R., Paul, F., Girard-Ardhuin, F., Chapron, B., Rehder, G., Ardhuin, F., and Donlon, C. J.: The FluxEngine air–sea gas flux toolbox: simplified interface and extensions for in situ analyses and multiple sparingly soluble gases, Ocean Sci., 15, 1707–1728, https://doi.org/10.5194/os-15-1707-2019, 2019.
Honkanen, M., Müller, J. D., Seppälä, J., Rehder, G., Kielosto, S., Ylöstalo, P., Mäkelä, T., Hatakka, J., and Laakso, L.: The diurnal cycle of pCO2 in the coastal region of the Baltic Sea, Ocean Sci., 17, 1657–1675, https://doi.org/10.5194/os-17-1657-2021, 2021.
Hoy, A., Hänsel, S., and Maugeri, M.: An endless summer: 2018 heat episodes in Europe in the context of secular temperature variability and change, Int. J. Climatol., 40, 6315–6336, https://doi.org/10.1002/joc.6582, 2020.
Humborg, C., Geibel, M. C., Sun, X., McCrackin, M., Mörth, C.-M., Stranne, C., Jakobsson, M., Gustafsson, B., Sokolov, A., Norkko, A., and Norkko, J.: High Emissions of Carbon Dioxide and Methane From the Coastal Baltic Sea at the End of a Summer Heat Wave, Front. Mar. Sci., 6, 493, https://doi.org/10.3389/fmars.2019.00493, 2019.
IOC, SCOR and IAPSO: The International Thermodynamic Equation of Seawater – 2010: Calculation and Use of Thermodynamic Properties, Intergovernmental Oceanographic Commission, Manuals and Guides No. 56, UNESCO, 196 pp., 2010.
Jacobs, E., Bittig, H. C., Gräwe, U., Graves, C. A., Glockzin, M., Müller, J. D., Schneider, B., and Rehder, G.: Upwelling-induced trace gas dynamics in the Baltic Sea inferred from 8 years of autonomous measurements on a ship of opportunity, Biogeosciences, 18, 2679–2709, https://doi.org/10.5194/bg-18-2679-2021, 2021.
Jakobs, G., Rehder, G., Jost, G., Kießlich, K., Labrenz, M., and Schmale, O.: Comparative studies of pelagic microbial methane oxidation within the redox zones of the Gotland Deep and Landsort Deep (central Baltic Sea), Biogeosciences, 10, 7863–7875, https://doi.org/10.5194/bg-10-7863-2013, 2013.
Jakobs, G., Holtermann, P., Berndmeyer, C., Rehder, G., Blumenberg, M., Jost, G., Nausch, G., and Schmale, O.: Seasonal and spatial methane dynamics in the water column of the central Baltic Sea (Gotland Sea), Cont. Shelf Res., 91, 12–25, https://doi.org/10.1016/j.csr.2014.07.005, 2014.
Kahru, M., Elken, J., Kotta, I., Simm, M., and Vilbaste, K.: Plankton distributions and processes across a front in the open Baltic sea, Mar. Ecol. Prog. Ser., 20, 101–111, 1984.
Keeling, R. F., Piper, S. C., Bollenbacher, A. F., and Walker, J. S.: Atmospheric Carbon Dioxide Record from Mauna Loa, CDIAC, ESS-DIVE repository [data set], https://doi.org/10.3334/CDIAC/ATG.035, 2009.
Kikas, V. and Lips, U.: Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007–2013, Ocean Sci., 12, 843–859, https://doi.org/10.5194/os-12-843-2016, 2016.
Knittel, K. and Boetius, A.: Anaerobic oxidation of methane: progress with an unknown process, Annu. Rev. Microbiol., 63, 311–334, https://doi.org/10.1146/annurev.micro.61.080706.093130, 2009.
Kock, A., Gebhardt, S., and Bange, H. W.: Methane emissions from the upwelling area off Mauritania (NW Africa), Biogeosciences, 5, 1119–1125, https://doi.org/10.5194/bg-5-1119-2008, 2008.
Kownacka, J., Busch, S., Göbel, J., Gromisz, S., Hällfors, H., Höglander, H., Huseby, S., Jaanus, A., Jakobsen, H. H., Johansen, M., Johansson, M., Jurgensone, I., Liebeke, N., Kobos, J., Kraśniewski, W., Kremp, A., Lehtinen, S., Olenina, I., v. Weber, M., and Wasmund, N.: Cyanobacteria biomass, 1990–2019, HELCOM Balt, Sea Environ. Fact Sheets, Online, Helsinki Commission, https://helcom.fi/wp-content/uploads/2022/04/BSEFS-Cyanobacteria-biomass-1990-2020.pdf (last access: 16 June 2023), 2022.
Kuliński, K. and Pempkowiak, J.: The carbon budget of the Baltic Sea, Biogeosciences, 8, 3219–3230, https://doi.org/10.5194/bg-8-3219-2011, 2011.
Kuliński, K., Schneider, B., Szymczycha, B., and Stokowski, M.: Structure and functioning of the acid–base system in the Baltic Sea, Earth Syst. Dynam., 8, 1107–1120, https://doi.org/10.5194/esd-8-1107-2017, 2017.
Kuss, J., Roeder, W., Wlost, K.-P., and DeGrandpre, M.D.: Time-series of surface water CO2 and oxygen measurements on a platform in the central Arkona Sea (Baltic Sea): Seasonality of uptake and release, Mar. Chem., 101, 220–232, https://doi.org/10.1016/j.marchem.2006.03.004, 2006.
Laanearu, J. and Lips, U.: Observed thermohaline fields and low-frequency currents in the Narva Bay, Proceedings of the Estonian Academy of Sciences Engineering, 9, 91–106, 2003.
Lainela, S., Jacobs, E., Luik, S.-T., Rehder, G., and Lips, U.: Seasonal dynamics and regional distribution patterns of CO2 and CH4 in the north-eastern Baltic Sea, TalTech Data Repository [data set], https://doi.org/10.48726/t22h5-jkx78, 2024.
Lehtoranta, J., Savchuk, O. P., Elken, J., Kim, D., Kuosa, H., Raateoja, M., Kauppila, P., Räike, A., and Pitkänen, H.: Atmospheric forcing controlling inter-annual nutrient dynamics in the open Gulf of Finland, J. Marine Syst., 171, 4–20, 2017.
Leppäranta, M. and Myrberg, K.: Physical Oceanography of the Baltic Sea, Springer Science & Business Media, 378 pp., ISBN 3540797033, 2009.
Liblik, T. and Lips, U.: Variability of synoptic-scale quasi-stationary thermohaline stratification patterns in the Gulf of Finland in summer 2009, Ocean Sci., 8, 603–614, https://doi.org/10.5194/os-8-603-2012, 2012.
Liblik, T., Laanemets, J., Raudsepp, U., Elken, J., and Suhhova, I.: Estuarine circulation reversals and related rapid changes in winter near-bottom oxygen conditions in the Gulf of Finland, Baltic Sea, Ocean Sci., 9, 917–930, https://doi.org/10.5194/os-9-917-2013, 2013.
Liblik, T., Väli, G., Salm, K., Laanemets, J., Lilover, M.-J., and Lips, U.: Quasi-steady circulation regimes in the Baltic Sea, Ocean Sci., 18, 857–879, https://doi.org/10.5194/os-18-857-2022, 2022.
Lilover, M. J., Lips, U., Laanearu, J., and Liljebladh, B.: Flow regime in the Irbe Strait, Aquat. Sci., 60, 253–265, 1998.
Lips, I. and Lips, U.: Abiotic factors influencing cyanobacterial bloom development in the Gulf of Finland (Baltic Sea), Hydrobiologia, 614, 133–140, https://doi.org/10.1007/s10750-008-9449-2, 2008.
Lips, I., Lips, U., and Liblik, T.: Consequences of coastal upwelling events on physical and chemical patterns in the central Gulf of Finland (Baltic Sea), Cont. Shelf Res., 29, 1836–1847, https://doi.org/10.1016/j.csr.2009.06.010, 2009.
Lips, I., Rünk, N., Kikas, V., Meerits, A., and Lips, U.: High-resolution dynamics of the spring bloom in the Gulf of Finland of the Baltic Sea, J. Marine Syst., 129, 135–149, https://doi.org/10.1016/j.jmarsys.2013.06.002, 2014.
Lips, U., Kikas, V., Liblik, T., and Lips, I.: Multi-sensor in situ observations to resolve the sub-mesoscale features in the stratified Gulf of Finland, Baltic Sea, Ocean Sci., 12, 715–732, https://doi.org/10.5194/os-12-715-2016, 2016a.
Lips, U., Zhurbas, V., Skudra, M., and Väli, G.: A numerical study of circulation in the Gulf of Riga, Baltic Sea. Part I: Whole-basin gyres and mean currents, Cont. Shelf Res., 112, 1–13, https://doi.org/10.1016/j.csr.2015.11.008, 2016b.
Lips, U., Laanemets, J., Lips, I., Liblik, T., Suhhova, I., and Suursaar, Ü.: Wind-driven residual circulation and related oxygen and nutrient dynamics in the Gulf of Finland (Baltic Sea) in winter, Estuar. Coast. Shelf S., 195, 4–15, https://doi.org/10.1016/j.ecss.2016.10.006, 2017.
Maljutenko, I. and Raudsepp, U.: Long-term mean, interannual and seasonal circulation in the Gulf of Finland – The wide salt wedge estuary or gulf type ROFI, J. Marine Syst., 195, 1–19, https://doi.org/10.1016/j.jmarsys.2019.03.004, 2019.
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.
Müller, J. D., Schneider, B., Gräwe, U., Fietzek, P., Wallin, M. B., Rutgersson, A., Wasmund, N., Krüger, S., and Rehder, G.: Cyanobacteria net community production in the Baltic Sea as inferred from profiling pCO2 measurements, Biogeosciences, 18, 4889–4917, https://doi.org/10.5194/bg-18-4889-2021, 2021.
Myllykangas, J. P., Hietanen, S., and Jilbert, T.: Legacy effects of eutrophication on modern methane dynamics in a boreal estuary, Estuar. Coasts, 43, 189–206, https://doi.org/10.1007/s12237-019-00677-0, 2020.
Myrberg, K. and Andrejev, O.: Main upwelling regions in the Baltic Sea – a statistical analysis based on three-dimensional modelling, Boreal Environ. Res., 8, 97–112, 2003.
Nightingale, P. D., Malin, G., Law, C. S., Watson, A. J., Liss, P. S., Liddicoat, M. I., Boutin, J., and Upstill-Goddard, R. C.: In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers, Global Biogeochem. Cy., 14, 373–387, https://doi.org/10.1029/1999GB900091, 2000.
Norman, M., Parampil, S. R., Rutgersson, A., and Sahlée, E.: Influence of coastal upwelling on the air–sea gas exchange of CO2 in a Baltic Sea Basin, Tellus B, 65, 21831, https://doi.org/10.3402/tellusb.v65i0.21831, 2013.
Ojaveer, E. (Ed.): Ecosystem of the Gulf of Riga between 1920 and 1990, Estonian Academy Publishers, Tallinn, 277 pp., ISBN 9985500652, 1995.
Otsmann, M., Suursaar, Ü., and Kullas, T.: The oscillatory nature of the flows in the system of straits and small semienclosed basins of the Baltic Sea, Cont. Shelf Res., 21, 1577–1603, https://doi.org/10.1016/S0278-4343(01)00002-4, 2001.
Parard, G., Rutgersson, A., Raj Parampil, S., and Charantonis, A. A.: The potential of using remote sensing data to estimate air–sea CO2 exchange in the Baltic Sea, Earth Syst. Dynam., 8, 1093–1106, https://doi.org/10.5194/esd-8-1093-2017, 2017.
Pavelson, J.: Mesoscale physical processes and the related impact on the summer nutrient fields and phytoplankton blooms in the western Gulf of Finland, PhD thesis, Department of Marine Systems, Tallinn University of Technology, Estonia, 38 pp., ISBN 9985595564, 2005.
Placke, M., Meier, H. E. M., Gräwe, U., Neumann, T., Frauen, C., and Liu, Y.: Long-Term Mean Circulation of the Baltic Sea as Represented by Various Ocean Circulation Models, Front. Mar. Sci., 5, 287, https://doi.org/10.3389/fmars.2018.00287, 2018.
Reeburgh, W. S.: Oceanic methane biogeochemistry, Chem. Rev., 107, 486–513, https://doi.org/10.1021/cr050362v, 2007.
Richey, J. E., Devol, A. H., Wofsy, S. C., Victoria, R., and Riberio, M. N.: Biogenic gases and the oxidation and reduction of carbon in Amazon River and floodplain waters, Limnol. Oceanogr., 33, 551–561, https://doi.org/10.4319/lo.1988.33.4.0551, 1988.
Roth, F., Sun, X., Geibel, M. C., Prytherch, J., Brüchert, V., Bonaglia, S., Broman, E., Nascimento, F., Norkko, A., and Humborg, C.: High spatiotemporal variability of methane concentrations challenges estimates of emissions across vegetated coastal ecosystems, Glob. Change Biol., 28, 4308–4322, https://doi.org/10.1111/gcb.16177, 2022.
Sabbaghzadeh, B., Arévalo-Martínez, D. L., Glockzin, M., Otto, S., and Rehder, G.: Meridional and Cross-Shelf Variability of N2O and CH4 in the Eastern-South Atlantic, J. Geophys. Res.-Oceans, 126, e2020JC016878, https://doi.org/10.1029/2020JC016878, 2021.
Schmale, O., Schneider v. Deimling, J., Gülzow, W., Nausch, G., Waniek, J. J., and Rehder, G.: Distribution of methane in the water column of the Baltic Sea, Geophys. Res. Lett., 37, L12604, https://doi.org/10.1029/2010GL043115, 2010.
Schmale, O., Wäge, J., Mohrholz, V., Wasmund, N., Gräwe, U., Rehder, G., Labrenz, M., and Loick-Wilde, N.: The contribution of zooplankton to methane supersaturation in the oxygenated upper waters of the central Baltic Sea, Limnol. Oceanogr., 63, 412–430, https://doi.org/10.1002/lno.10640, 2018.
Schneider, B. and Müller, J. D.: Biogeochemical Transformations in the Baltic Sea, Springer Oceanography, Springer International Publishing, Cham, Switzerland, https://doi.org/10.1007/978-3-319-61699-5, 2018.
Schneider, B., Gülzow, W., Sadkowiak, B., and Rehder, G.: Detecting sinks and sources of CO2 and CH4 by ferrybox-based measurements in the Baltic Sea: Three case studies, J. Marine Syst., 140, 13–25, https://doi.org/10.1016/j.jmarsys.2014.03.014, 2014.
Seppälä, J. and Balode, M.: Spatial distribution of phytoplankton in the Gulf of Riga during spring and summer stages, J. Marine Syst., 23, 51–67, https://doi.org/10.1016/S0924-7963(99)00050-0, 1999.
Shutler, J. D., Land, P. E., Piolle, J. F., Woolf, D. K., Goddijn-Murphy, L., Paul, F., Girard-Ardhuin, F., Chapron, B., and Donlon, C. J.: FluxEngine: a flexible processing system for calculating atmosphere-ocean carbon dioxide gas fluxes and climatologies, J. Atmos. Ocean. Tech., 33, 741–756, https://doi.org/10.1175/JTECH-D-14-00204.1, 2016.
Skudra, M. and Lips, U.: Characteristics and inter-annual changes in temperature, salinity and density distribution in the Gulf of Riga, Oceanologia, 59, 37–48, https://doi.org/10.1016/j.oceano.2016.07.001, 2017.
Soosaar, E., Maljutenko, I., Uiboupin, R., Skudra, M., and Raudsepp, U.: River bulge evolution and dynamics in a non-tidal sea – Daugava River plume in the Gulf of Riga, Baltic Sea, Ocean Sci., 12, 417–432, https://doi.org/10.5194/os-12-417-2016, 2016.
Stawiarski, B., Otto, S., Thiel, V., Gräwe, U., Loick-Wilde, N., Wittenborn, A. K., Schloemer, S., Wäge, J., Rehder, G., Labrenz, M., Wasmund, N., and Schmale, O.: Controls on zooplankton methane production in the central Baltic Sea, Biogeosciences, 16, 1–16, https://doi.org/10.5194/bg-16-1-2019, 2019.
Stålnacke, P., Grimvall, A., Sundblad, K., and Tonderski, A.: Estimation of riverine loads of nitrogen and phosphorus to the Baltic Sea, 1970–1993, Environ. Monit. Assess., 58, 173–200, https://doi.org/10.1023/A:1006073015871, 1999.
Stiebrins, O. and Väling, P.: Bottom sediments of the Gulf of Riga, Geol. Surv. Latv. Riga, 4 pp., ISBN 9984-9130-0-7, 1996.
Stoicescu, S.-T., Lips, U., and Liblik, T.: Assessment of Eutrophication Status Based on Sub-Surface Oxygen Conditions in the Gulf of Finland (Baltic Sea), Front. Mar. Sci., 6, 54, https://doi.org/10.3389/fmars.2019.00054, 2019.
Stoicescu, S.-T., Laanemets, J., Liblik, T., Skudra, M., Samlas, O., Lips, I., and Lips, U.: Causes of the extensive hypoxia in the Gulf of Riga in 2018, Biogeosciences, 19, 2903–2920, https://doi.org/10.5194/bg-19-2903-2022, 2022.
Suursaar, Ü., Kullas, T., and Otsmann, M.: The influence of currents and waves on ecological conditions of the Väinameri, Proceedings of the Estonian Academy of Sciences Biology Ecology, 50, 231–247, 2001.
Takahashi, T., Olafsson, J., Goddard, J. G., Chipman, D. W., and Sutherland, S. C.: Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: A comparative study, Global Biogeochem. Cy., 7, 843–878, https://doi.org/10.1029/93GB02263, 1993.
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.
Townsend, D. W., Cammen, L. M., Holligan, P. M., Campbell, D., and Pettigrew, N. R.: Causes and consequences of variability in the timing of spring phytoplankton blooms, Deep-Sea Res. Pt. I, 41, 747–765, https://doi.org/10.1016/0967-0637(94)90075-2, 1994.
Valentine, D. L.: Biogeochemistry and microbial ecology of methane oxidation in anoxic environments: a review, A. Van Leeuw. J. Mocrob., 81, 271–282, https://doi.org/10.1023/A:1020587206351, 2002.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean revisited, Limnol. Oceanogr.-Meth., 12, 351–362, https://doi.org/10.4319/lom.2014.12.351, 2014.
Weber, T., Wiseman, N. A., and Kock, A.: Global ocean methane emissions dominated by shallow coastal waters, Nat. Commun., 10, 4584, https://doi.org/10.1038/s41467-019-12541-7, 2019.
Weiss, R. F. and Price, B. A.: Nitrous oxide solubility in water and seawater, Mar. Chem., 8, 347–359, https://doi.org/10.1016/0304-4203(80)90024-9, 1980.
Wesslander, K., Omstedt, A., and Schneider, B.: Inter-annual and seasonal variations in the air–sea CO2 balance in the central Baltic Sea and the Kattegat, Cont. Shelf Res., 30, 1511–1521, https://doi.org/10.1016/j.csr.2010.05.014, 2010.
Wesslander, K., Hall, P., Hjalmarsson, S., Lefevre, D., Omstedt, A., Rutgersson, A., Sahlée, E., and Tengberg, A.: Observed carbon dioxide and oxygen dynamics in a Baltic Sea coastal region, J. Marine Syst., 86, 1–9, https://doi.org/10.1016/j.jmarsys.2011.01.001, 2011.
Wiesenburg, D. A. and Guinasso, N. L.: Equilibrium solubilities of methane, carbon monoxide, and hydrogen in water and sea water, J. Chem. Eng. Data, 24, 356–360, https://doi.org/10.1021/je60083a006, 1979.
Woolf, D. K., Land, P. E., Shutler, J. D., Goddijn-Murphy, L. M., and Donlon, C. J.: On the calculation of air-sea fluxes of CO2 in the presence of temperature and salinity gradients, J. Geophys. Res.-Oceans, 121, 1229–1248, https://doi.org/10.1002/2015JC011427, 2016.
Yurkovskis, A., Wulff, F., Rahm, L., Andruzaitis, A., and Rodriguez-Medina, M.: A Nutrient Budget of the Gulf of Riga; Baltic Sea, Estuar. Coast. Shelf S., 37, 113–127, https://doi.org/10.1006/ecss.1993.1046, 1993.
Short summary
We evaluate the variability of carbon dioxide and methane in the surface layer of the north-eastern basins of the Baltic Sea in 2018. We show that the shallower coastal areas have considerably higher spatial variability and seasonal amplitude of surface layer pCO2 and cCH4 than measured in the offshore areas of the Baltic Sea. Despite this high variability, caused mostly by coastal physical processes, the average annual air–sea CO2 fluxes differed only marginally between the sub-basins.
We evaluate the variability of carbon dioxide and methane in the surface layer of the...
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