Articles | Volume 18, issue 14
https://doi.org/10.5194/bg-18-4243-2021
© Author(s) 2021. 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-18-4243-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
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20 Jul 2021
Research article | Highlight paper |
| 20 Jul 2021
| 20 Jul 2021
Retracing hypoxia in Eckernförde Bight (Baltic Sea)
Heiner Dietze
Institut für Geowissenschaften, CAU Kiel, Ludewig-Meyn-Str. 10, 24118 Kiel, Germany
Ulrike Löptien
CORRESPONDING AUTHOR
Institut für Geowissenschaften, CAU Kiel, Ludewig-Meyn-Str. 10, 24118 Kiel, Germany
Related authors
Heiner Dietze and Ulrike Löptien
EGUsphere, https://doi.org/10.5194/egusphere-2024-918, https://doi.org/10.5194/egusphere-2024-918, 2024
Short summary
Short summary
We introduce argon saturation as a prognostic variable in a suite of coupled general ocean circulation biogeochemical models off Mauretania. Our results indicate that the effect of increasing the spatial horizontal model resolutions from 12 km to 1.5 km leads to changes comparable to other infamous spurious effects of state-of-the-art numerical advection numerics.
Ulrike Löptien and Heiner Dietze
Biogeosciences, 16, 1865–1881, https://doi.org/10.5194/bg-16-1865-2019, https://doi.org/10.5194/bg-16-1865-2019, 2019
Short summary
Short summary
Anthropogenic greenhouse gas emissions trigger complex climate feedbacks. Output form Earth system models provides a basis for related political decision-making. One challenge is to arrive at reliable model parameter estimates for the ocean biogeochemistry module. We illustrate pitfalls through which flaws in the ocean module are masked by wrongly tuning the biogeochemistry and discuss ensuing uncertainties in climate projections.
Karin F. Kvale, Samar Khatiwala, Heiner Dietze, Iris Kriest, and Andreas Oschlies
Geosci. Model Dev., 10, 2425–2445, https://doi.org/10.5194/gmd-10-2425-2017, https://doi.org/10.5194/gmd-10-2425-2017, 2017
Short summary
Short summary
Computer models of ocean biology and chemistry are becoming increasingly complex, and thus more expensive, to run. One solution is to approximate the behaviour of the ocean physics and store that information outside of the model. That
offlineinformation can then be used to calculate a steady-state solution from the model's biology and chemistry, without waiting for a traditional
onlineintegration to complete. We show this offline method reproduces online results and is 100 times faster.
Heiner Dietze, Julia Getzlaff, and Ulrike Löptien
Biogeosciences, 14, 1561–1576, https://doi.org/10.5194/bg-14-1561-2017, https://doi.org/10.5194/bg-14-1561-2017, 2017
Short summary
Short summary
The Southern Ocean is a sink for anthropogenic carbon. Projections of how this sink will evolve in an ever-warming climate are based on coupled ocean-circulation–biogeochemical models. This study compares uncertainties of simulated oceanic carbon uptake associated to physical (eddy) parameterizations with those associated wtih (unconstrained) supply of bioavailable iron supply to the surface ocean.
Yonss Saranga José, Heiner Dietze, and Andreas Oschlies
Biogeosciences, 14, 1349–1364, https://doi.org/10.5194/bg-14-1349-2017, https://doi.org/10.5194/bg-14-1349-2017, 2017
Short summary
Short summary
This study aims to investigate the diverse subsurface nutrient patterns observed within anticyclonic eddies in the upwelling system off Peru. Two simulated anticyclonic eddies with opposing subsurface nitrate concentrations were analysed. The results show that diverse nutrient patterns within anticyclonic eddies are related to the presence of water mass from different origins at different depths, responding to variations in depth of the circulation strength at the edge of the eddy.
Heiner Dietze and Ulrike Löptien
Ocean Sci., 12, 977–986, https://doi.org/10.5194/os-12-977-2016, https://doi.org/10.5194/os-12-977-2016, 2016
Short summary
Short summary
Winds blowing over the ocean drive ocean currents. The oceanic response to winds is, in turn, influenced by ocean currents. Theoretical considerations suggest that the latter effect is especially pronounced in the Baltic Sea. The study presented here puts theses theoretical considerations in a high-resolution ocean circulation model of the Baltic Sea to the test.
U. Löptien and H. Dietze
Ocean Sci., 11, 573–590, https://doi.org/10.5194/os-11-573-2015, https://doi.org/10.5194/os-11-573-2015, 2015
Short summary
Short summary
Marine biogeochemical ocean models are embedded into earth system models - which are, to an increasing degree, applied to project the fate of our warming world. These biogeochemical models generally depend on poorly constrained model parameters. In this study we investigate the the demands on observations for an objective estimation of such parameters. A major result is that even modest noise (10%) inherent to observations can hinder the assignment of reasonable parameters.
U. Löptien and H. Dietze
Earth Syst. Sci. Data, 6, 367–374, https://doi.org/10.5194/essd-6-367-2014, https://doi.org/10.5194/essd-6-367-2014, 2014
H. Dietze, U. Löptien, and K. Getzlaff
Geosci. Model Dev., 7, 1713–1731, https://doi.org/10.5194/gmd-7-1713-2014, https://doi.org/10.5194/gmd-7-1713-2014, 2014
A. Landolfi, H. Dietze, W. Koeve, and A. Oschlies
Biogeosciences, 10, 1351–1363, https://doi.org/10.5194/bg-10-1351-2013, https://doi.org/10.5194/bg-10-1351-2013, 2013
Heiner Dietze and Ulrike Löptien
EGUsphere, https://doi.org/10.5194/egusphere-2024-918, https://doi.org/10.5194/egusphere-2024-918, 2024
Short summary
Short summary
We introduce argon saturation as a prognostic variable in a suite of coupled general ocean circulation biogeochemical models off Mauretania. Our results indicate that the effect of increasing the spatial horizontal model resolutions from 12 km to 1.5 km leads to changes comparable to other infamous spurious effects of state-of-the-art numerical advection numerics.
Ulrike Löptien and Heiner Dietze
Biogeosciences, 16, 1865–1881, https://doi.org/10.5194/bg-16-1865-2019, https://doi.org/10.5194/bg-16-1865-2019, 2019
Short summary
Short summary
Anthropogenic greenhouse gas emissions trigger complex climate feedbacks. Output form Earth system models provides a basis for related political decision-making. One challenge is to arrive at reliable model parameter estimates for the ocean biogeochemistry module. We illustrate pitfalls through which flaws in the ocean module are masked by wrongly tuning the biogeochemistry and discuss ensuing uncertainties in climate projections.
Karin F. Kvale, Samar Khatiwala, Heiner Dietze, Iris Kriest, and Andreas Oschlies
Geosci. Model Dev., 10, 2425–2445, https://doi.org/10.5194/gmd-10-2425-2017, https://doi.org/10.5194/gmd-10-2425-2017, 2017
Short summary
Short summary
Computer models of ocean biology and chemistry are becoming increasingly complex, and thus more expensive, to run. One solution is to approximate the behaviour of the ocean physics and store that information outside of the model. That
offlineinformation can then be used to calculate a steady-state solution from the model's biology and chemistry, without waiting for a traditional
onlineintegration to complete. We show this offline method reproduces online results and is 100 times faster.
Heiner Dietze, Julia Getzlaff, and Ulrike Löptien
Biogeosciences, 14, 1561–1576, https://doi.org/10.5194/bg-14-1561-2017, https://doi.org/10.5194/bg-14-1561-2017, 2017
Short summary
Short summary
The Southern Ocean is a sink for anthropogenic carbon. Projections of how this sink will evolve in an ever-warming climate are based on coupled ocean-circulation–biogeochemical models. This study compares uncertainties of simulated oceanic carbon uptake associated to physical (eddy) parameterizations with those associated wtih (unconstrained) supply of bioavailable iron supply to the surface ocean.
Yonss Saranga José, Heiner Dietze, and Andreas Oschlies
Biogeosciences, 14, 1349–1364, https://doi.org/10.5194/bg-14-1349-2017, https://doi.org/10.5194/bg-14-1349-2017, 2017
Short summary
Short summary
This study aims to investigate the diverse subsurface nutrient patterns observed within anticyclonic eddies in the upwelling system off Peru. Two simulated anticyclonic eddies with opposing subsurface nitrate concentrations were analysed. The results show that diverse nutrient patterns within anticyclonic eddies are related to the presence of water mass from different origins at different depths, responding to variations in depth of the circulation strength at the edge of the eddy.
Heiner Dietze and Ulrike Löptien
Ocean Sci., 12, 977–986, https://doi.org/10.5194/os-12-977-2016, https://doi.org/10.5194/os-12-977-2016, 2016
Short summary
Short summary
Winds blowing over the ocean drive ocean currents. The oceanic response to winds is, in turn, influenced by ocean currents. Theoretical considerations suggest that the latter effect is especially pronounced in the Baltic Sea. The study presented here puts theses theoretical considerations in a high-resolution ocean circulation model of the Baltic Sea to the test.
U. Löptien and H. Dietze
Ocean Sci., 11, 573–590, https://doi.org/10.5194/os-11-573-2015, https://doi.org/10.5194/os-11-573-2015, 2015
Short summary
Short summary
Marine biogeochemical ocean models are embedded into earth system models - which are, to an increasing degree, applied to project the fate of our warming world. These biogeochemical models generally depend on poorly constrained model parameters. In this study we investigate the the demands on observations for an objective estimation of such parameters. A major result is that even modest noise (10%) inherent to observations can hinder the assignment of reasonable parameters.
U. Löptien and H. Dietze
Earth Syst. Sci. Data, 6, 367–374, https://doi.org/10.5194/essd-6-367-2014, https://doi.org/10.5194/essd-6-367-2014, 2014
H. Dietze, U. Löptien, and K. Getzlaff
Geosci. Model Dev., 7, 1713–1731, https://doi.org/10.5194/gmd-7-1713-2014, https://doi.org/10.5194/gmd-7-1713-2014, 2014
A. Landolfi, H. Dietze, W. Koeve, and A. Oschlies
Biogeosciences, 10, 1351–1363, https://doi.org/10.5194/bg-10-1351-2013, https://doi.org/10.5194/bg-10-1351-2013, 2013
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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
The Northeast Greenland Shelf as a potential late-summer CO2 source to the atmosphere
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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
Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait
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)
The influence of zooplankton and oxygen on the particulate organic carbon flux in the Benguela Upwelling System
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Reviews and syntheses: Biological Indicators of Oxygen Stress in Water Breathing Animals
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
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Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
Assessing impacts of coastal warming, acidification, and deoxygenation on Pacific oyster (Crassostrea gigas) farming: a case study in the Hinase area, Okayama Prefecture, and Shizugawa Bay, Miyagi Prefecture, Japan
Multiple nitrogen sources for primary production inferred from δ13C and δ15N in the southern Sea of Japan
Influence of manganese cycling on alkalinity in the redox stratified water column of Chesapeake Bay
Estuarine flocculation dynamics of organic carbon and metals from boreal acid sulfate soils
Drivers of particle sinking velocities in the Peruvian upwelling system
Impacts and uncertainties of climate-induced changes in watershed inputs on estuarine hypoxia
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed
High metabolism and periodic hypoxia associated with drifting macrophyte detritus in the shallow subtidal Baltic Sea
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Zooplankton community succession and trophic links during a mesocosm experiment in the coastal upwelling off Callao Bay (Peru)
Temporal and spatial evolution of bottom-water hypoxia in the St Lawrence estuarine system
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Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
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Limits and CO2 equilibration of near-coast alkalinity enhancement
Role of phosphorus in the seasonal deoxygenation of the East China Sea shelf
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
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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
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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.
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
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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.
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
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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
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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
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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
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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
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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.
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
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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.
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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
Luisa Chiara Meiritz, Tim Rixen, Anja K. van der Plas, Tarron Lamont, and Niko Lahajnar
EGUsphere, https://doi.org/10.5194/egusphere-2024-700, https://doi.org/10.5194/egusphere-2024-700, 2024
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The transport of particles through the water column and their subsequent burial on the seafloor is an important process for carbon storage and the mediation of carbon dioxide in the oceans. Our results from the Benguela Upwelling System distinguish between the northern and southern parts of the study area and between passive (gravitational) and active (zooplankton) transport processes. The decomposition of organic matter is doubtlessly an important factor for the size of oxygen minimum zones.
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
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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
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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.
Michael R. Roman, Andrew H. Altieri, Denise Breitburg, Erica Ferrer, Natalya D. Gallo, Shin-ichi Ito, Karin Limburg, Kenneth Rose, Moriaki Yasuhara, and Lisa A. Levin
EGUsphere, https://doi.org/10.5194/egusphere-2024-616, https://doi.org/10.5194/egusphere-2024-616, 2024
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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 oxygen stress for marine animals including their use, research needs and application to confront the challenges of ocean oxygen loss.
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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
Biogeosciences, 20, 4875–4891, https://doi.org/10.5194/bg-20-4875-2023, https://doi.org/10.5194/bg-20-4875-2023, 2023
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Benthic foraminifera are single-cell marine organisms which can move in the sediment column. They were previously reported to horizontally and vertically transport sediment particles, yet the impact of their motion on the dissolved fluxes remains unknown. Using microprofiling, we show here that foraminiferal burrow formation increases the oxygen penetration depth in the sediment, leading to a change in the structure of the prokaryotic community.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences, 20, 4527–4549, https://doi.org/10.5194/bg-20-4527-2023, https://doi.org/10.5194/bg-20-4527-2023, 2023
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This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae as a result of longer exposure to lower-pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.
Taketoshi Kodama, Atsushi Nishimoto, Ken-ichi Nakamura, Misato Nakae, Naoki Iguchi, Yosuke Igeta, and Yoichi Kogure
Biogeosciences, 20, 3667–3682, https://doi.org/10.5194/bg-20-3667-2023, https://doi.org/10.5194/bg-20-3667-2023, 2023
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Carbon and nitrogen are essential elements for organisms; their stable isotope ratios (13C : 12C, 15N : 14N) are useful tools for understanding turnover and movement in the ocean. In the Sea of Japan, the environment is rapidly being altered by human activities. The 13C : 12C of small organic particles is increased by active carbon fixation, and phytoplankton growth increases the values. The 15N : 14N variations suggest that nitrates from many sources contribute to organic production.
Aubin Thibault de Chanvalon, George W. Luther, Emily R. Estes, Jennifer Necker, Bradley M. Tebo, Jianzhong Su, and Wei-Jun Cai
Biogeosciences, 20, 3053–3071, https://doi.org/10.5194/bg-20-3053-2023, https://doi.org/10.5194/bg-20-3053-2023, 2023
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The intensity of the oceanic trap of CO2 released by anthropogenic activities depends on the alkalinity brought by continental weathering. Between ocean and continent, coastal water and estuaries can limit or favour the alkalinity transfer. This study investigate new interactions between dissolved metals and alkalinity in the oxygen-depleted zone of estuaries.
Joonas J. Virtasalo, Peter Österholm, and Eero Asmala
Biogeosciences, 20, 2883–2901, https://doi.org/10.5194/bg-20-2883-2023, https://doi.org/10.5194/bg-20-2883-2023, 2023
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We mixed acidic metal-rich river water from acid sulfate soils and seawater in the laboratory to study the flocculation of dissolved metals and organic matter in estuaries. Al and Fe flocculated already at a salinity of 0–2 to large organic flocs (>80 µm size). Precipitation of Al and Fe hydroxide flocculi (median size 11 µm) began when pH exceeded ca. 5.5. Mn transferred weakly to Mn hydroxides and Co to the flocs. Up to 50 % of Cu was associated with the flocs, irrespective of seawater mixing.
Moritz Baumann, Allanah Joy Paul, Jan Taucher, Lennart Thomas Bach, Silvan Goldenberg, Paul Stange, Fabrizio Minutolo, and Ulf Riebesell
Biogeosciences, 20, 2595–2612, https://doi.org/10.5194/bg-20-2595-2023, https://doi.org/10.5194/bg-20-2595-2023, 2023
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The sinking velocity of marine particles affects how much atmospheric CO2 is stored inside our oceans. We measured particle sinking velocities in the Peruvian upwelling system and assessed their physical and biochemical drivers. We found that sinking velocity was mainly influenced by particle size and porosity, while ballasting minerals played only a minor role. Our findings help us to better understand the particle sinking dynamics in this highly productive marine system.
Kyle E. Hinson, Marjorie A. M. Friedrichs, Raymond G. Najjar, Maria Herrmann, Zihao Bian, Gopal Bhatt, Pierre St-Laurent, Hanqin Tian, and Gary Shenk
Biogeosciences, 20, 1937–1961, https://doi.org/10.5194/bg-20-1937-2023, https://doi.org/10.5194/bg-20-1937-2023, 2023
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Climate impacts are essential for environmental managers to consider when implementing nutrient reduction plans designed to reduce hypoxia. This work highlights relative sources of uncertainty in modeling regional climate impacts on the Chesapeake Bay watershed and consequent declines in bay oxygen levels. The results demonstrate that planned water quality improvement goals are capable of reducing hypoxia levels by half, offsetting climate-driven impacts on terrestrial runoff.
Linquan Mu, Jaime B. Palter, and Hongjie Wang
Biogeosciences, 20, 1963–1977, https://doi.org/10.5194/bg-20-1963-2023, https://doi.org/10.5194/bg-20-1963-2023, 2023
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Enhancing ocean alkalinity accelerates carbon dioxide removal from the atmosphere. We hypothetically added alkalinity to the Amazon River and examined the increment of the carbon uptake by the Amazon plume. We also investigated the minimum alkalinity addition in which this perturbation at the river mouth could be detected above the natural variability.
Karl M. Attard, Anna Lyssenko, and Iván F. Rodil
Biogeosciences, 20, 1713–1724, https://doi.org/10.5194/bg-20-1713-2023, https://doi.org/10.5194/bg-20-1713-2023, 2023
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Aquatic plants produce a large amount of organic matter through photosynthesis that, following erosion, is deposited on the seafloor. In this study, we show that plant detritus can trigger low-oxygen conditions (hypoxia) in shallow coastal waters, making conditions challenging for most marine animals. We propose that the occurrence of hypoxia may be underestimated because measurements typically do not consider the region closest to the seafloor, where detritus accumulates.
M. James McLaughlin, Cindy Bessey, Gary A. Kendrick, John Keesing, and Ylva S. Olsen
Biogeosciences, 20, 1011–1026, https://doi.org/10.5194/bg-20-1011-2023, https://doi.org/10.5194/bg-20-1011-2023, 2023
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Coral reefs face increasing pressures from environmental change at present. The coral reef framework is produced by corals and calcifying algae. The Kimberley region of Western Australia has escaped land-based anthropogenic impacts. Specimens of the dominant coral and algae were collected from Browse Island's reef platform and incubated in mesocosms to measure calcification and production patterns of oxygen. This study provides important data on reef building and climate-driven effects.
Patricia Ayón Dejo, Elda Luz Pinedo Arteaga, Anna Schukat, Jan Taucher, Rainer Kiko, Helena Hauss, Sabrina Dorschner, Wilhelm Hagen, Mariona Segura-Noguera, and Silke Lischka
Biogeosciences, 20, 945–969, https://doi.org/10.5194/bg-20-945-2023, https://doi.org/10.5194/bg-20-945-2023, 2023
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Ocean upwelling regions are highly productive. With ocean warming, severe changes in upwelling frequency and/or intensity and expansion of accompanying oxygen minimum zones are projected. In a field experiment off Peru, we investigated how different upwelling intensities affect the pelagic food web and found failed reproduction of dominant zooplankton. The changes projected could severely impact the reproductive success of zooplankton communities and the pelagic food web in upwelling regions.
Mathilde Jutras, Alfonso Mucci, Gwenaëlle Chaillou, William A. Nesbitt, and Douglas W. R. Wallace
Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, https://doi.org/10.5194/bg-20-839-2023, 2023
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The deep waters of the lower St Lawrence Estuary and gulf have, in the last decades, experienced a strong decline in their oxygen concentration. Below 65 µmol L-1, the waters are said to be hypoxic, with dire consequences for marine life. We show that the extent of the hypoxic zone shows a seven-fold increase in the last 20 years, reaching 9400 km2 in 2021. After a stable period at ~ 65 µmol L⁻¹ from 1984 to 2019, the oxygen level also suddenly decreased to ~ 35 µmol L-1 in 2020.
Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, and Atsushi Ooki
Biogeosciences, 20, 421–438, https://doi.org/10.5194/bg-20-421-2023, https://doi.org/10.5194/bg-20-421-2023, 2023
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We conducted repetitive observations in Funka Bay, Japan, during the spring bloom 2019. We found nutrient concentration decreases in the dark subsurface layer during the bloom. Incubation experiments confirmed that diatoms could consume nutrients at a substantial rate, even in darkness. We concluded that the nutrient reduction was mainly caused by nutrient consumption by diatoms in the dark.
Dirk Jong, Lisa Bröder, Tommaso Tesi, Kirsi H. Keskitalo, Nikita Zimov, Anna Davydova, Philip Pika, Negar Haghipour, Timothy I. Eglinton, and Jorien E. Vonk
Biogeosciences, 20, 271–294, https://doi.org/10.5194/bg-20-271-2023, https://doi.org/10.5194/bg-20-271-2023, 2023
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With this study, we want to highlight the importance of studying both land and ocean together, and water and sediment together, as these systems function as a continuum, and determine how organic carbon derived from permafrost is broken down and its effect on global warming. Although on the one hand it appears that organic carbon is removed from sediments along the pathway of transport from river to ocean, it also appears to remain relatively ‘fresh’, despite this removal and its very old age.
Georgia Filippi, Manos Dassenakis, Vasiliki Paraskevopoulou, and Konstantinos Lazogiannis
Biogeosciences, 20, 163–189, https://doi.org/10.5194/bg-20-163-2023, https://doi.org/10.5194/bg-20-163-2023, 2023
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The pollution of the western Saronikos Gulf from heavy metals has been examined through the study of marine sediment cores. It is a deep gulf (maximum depth 440 m) near Athens affected by industrial and volcanic activity. Eight cores were received from various stations and depths and analysed for their heavy metal content and geochemical characteristics. The results were evaluated by using statistical methods, environmental indicators and comparisons with old data.
Jing He and Michael D. Tyka
Biogeosciences, 20, 27–43, https://doi.org/10.5194/bg-20-27-2023, https://doi.org/10.5194/bg-20-27-2023, 2023
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Recently, ocean alkalinity enhancement (OAE) has gained interest as a scalable way to address the urgent need for negative CO2 emissions. In this paper we examine the capacity of different coastlines to tolerate alkalinity enhancement and the time scale of CO2 uptake following the addition of a given quantity of alkalinity. The results suggest that OAE has significant potential and identify specific favorable and unfavorable coastlines for its deployment.
Arnaud Laurent, Haiyan Zhang, and Katja Fennel
Biogeosciences, 19, 5893–5910, https://doi.org/10.5194/bg-19-5893-2022, https://doi.org/10.5194/bg-19-5893-2022, 2022
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The Changjiang is the main terrestrial source of nutrients to the East China Sea (ECS). Nutrient delivery to the ECS has been increasing since the 1960s, resulting in low oxygen (hypoxia) during phytoplankton decomposition in summer. River phosphorus (P) has increased less than nitrogen, and therefore, despite the large nutrient delivery, phytoplankton growth can be limited by the lack of P. Here, we investigate this link between P limitation, phytoplankton production/decomposition, and hypoxia.
Cited articles
Ærtebjerg, N. G., Jacobsen, T. S., Gargas, E., and Buche, E: The Belt project. Evaluation of the physical, chemical and biological measurements, National Agency for Environmental Protection, Denmark, 1981. a
Arakawa, A. and Lamb, V. R.: Computational design of the basic dynamical processes of the UCLA general circulation model, Methods in Computational Physics: Advances in Research and Applications, 17, Academic Press, 173–265, https://doi.org/10.1016/B978-0-12-460817-7.50009-4, 1977. a, b, c
Arteaga, L. A., Boss, E., Behrenfeld, M. J., Westberry, T. K., and Sarmiento, J. L.: Seasonal modulation of phytoplankton biomass in the Southern Ocean, Nat. Commun., 22, 5364, https://doi.org/10.1038/s41467-020-19157-2, 2020. a
Bange, H. and Frank, M.: Hydrochemistry from time series station Boknis Eck from 1957 to 2014, Zenodo [Dataset], https://doi.org/10.1594/PANGAEA.855693 (last access: 15 July 2021), 2015.
Behrenfeld, M. J.: Abandoning Sverdrup's Critical Depth Hypothesis on phytoplankton blooms, Ecology, 91, 977–989, https://doi.org/10.1890/09-1207.1, 2010. a
Bendtsen, J. and Hansen, J. L. S.: Effects of global warming on hypoxia in the Baltic Sea-North Sea transition zone, Ecol. Model., 264, 17–26, https://doi.org/10.1016/j.ecolmodel.2012.06.018, 2013. a, b, c
Blayo, E. and Debreu, L.: Revisiting open boundary conditions from the point of view of characteristic variables, Ocean Model., 9, 3, 231–252, https://doi.org/10.1016/j.ocemod.2004.07.001, 2005. a, b
Brunton, S. L., Noack, B. R., and Koumoutsakos, P.: Machine Learning for Fluid Mechanics, Annual Review of Fluid Dynamics, 52, 477–508, https://doi.org/10.1146/annurev-fluid-010719-060214, 2020a. a
Brunton, S. L., Hemati, M. S., and Kunihiko, T.: Special issue on machine
learning and data-driven methods in fluid dynamics, Theor. Comp. Fluid Dyn.,
34, 333–337, https://doi.org/10.1007/s00162-020-00542-y, 2020b. a
Burchard, H., Craig, P. D., Gemmrich, J. R., van Haren, H., Mathieu, P. P., Meier, H. M., Nimmo Smith, W. A. M., Prandke, H., Rippeth, T. P., Skyllingstad, E. D., Smyth, W. D., Welsh, D. J. K., and Wijesekera, W.: Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing, Prog. Oceanogr., 76, 399–442, https://doi.org/10.1016/j.pocean.2007.09.005, 2008. a
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, 15, 5628–5633, https://doi.org/10.1073/pnas.1323156111, 2014. a
Carton, J. A. and Chao, Y.: Caribbean Sea eddies inferred from TOPEX/POSEIDON
altimetry and a 1/6∘ Atlantic Ocean model simulation,
J. Geophys. Res., 104, 7743–7752, https://doi.org/10.1029/1998JC900081, 1999. a
Castruccio, S., McInerney, D. J., Stein, M. L., Crouch, F. L., Jacob, R. L., and Moyer, E. J.: Statistical Emulation of Climate Model Projections Based on Precomputed GCM Runs, J. Climate, 27, 1829–1844, https://doi.org/10.1175/JCLI-D-13-00099.1, 2014. a
Cocco, V., Joos, F., Steinacher, M., Frölicher, T. L., Bopp, L., Dunne, J., Gehlen, M., Heinze, C., Orr, J., Oschlies, A., Schneider, B., Segschneider, J., and Tjiputra, J.: Oxygen and indicators of stress for marine life in multi-model global warming projections, Biogeosciences, 10, 1849–1868, https://doi.org/10.5194/bg-10-1849-2013, 2013. a
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. a
Dietterich, T. G.: Machine Learning for Sequential Data: A Review, in: Structural, Syntactic, and Statistical Pattern Recognition, edited by: Caelli, T., Amin, A., Duin, R. P. W., de Ridder, D., and Kamel, M., Springer, Berlin, Heidelberg, 15–30, https://doi.org/10.1007/3-540-70659-3_2, 2002. a
Dietze, H. and Kriest, I.: 137Cs off Fukushima Dai-ichi, Japan – model based estimates of dilution and fate, Ocean Sci., 8, 319–332, https://doi.org/10.5194/os-8-319-2012, 2012. a
Dietze, H. and Löptien, U.: Revisiting “nutrient trapping” in global
biogeochemical ocean circulation models, Global Biogeochem. Cy., 27, 265–284,
https://doi.org/10.1002/gbc.20029, 2013. a
Dietze, H. and Löptien, U.: Frühwarnsystem Upwelling (FRAM), Zenodo [Dataset], https://doi.org/10.5281/zenodo.4271941 (last access: 15 July 2021), 2020.
Dietze, H., Matear, R., and Moore, T.: Nutrient supply to anticyclonic meso-scale eddies off western Australia estimated with artificial tracers released in a circulation model, Deep-Sea Res. Pt. I, 56, 1440–1448, https://doi.org/10.1016/j.dsr.2009.04.012, 2009. a
Dietze, H., Getzlaff, J., and Löptien, U.: Simulating natural carbon sequestration in the Southern Ocean: on uncertainties associated with eddy parameterizations and iron deposition, Biogeosciences, 14, 1561–1576, https://doi.org/10.5194/bg-14-1561-2017, 2017. a
Dietze, H., Löptien, U., and Getzlaff, J.: MOMSO 1.0 – an eddying Southern Ocean model configuration with fairly equilibrated natural carbon, Geosci. Model Dev., 13, 71–97, https://doi.org/10.5194/gmd-13-71-2020, 2020. a, b, c, d
Fennel, K. and Testa, J. M.: Biogeochemical Controls on Coastal Hypoxia,
Annu. Rev. Mar. Sci., 11, 105–130, https://doi.org/10.1146/annurev-marine-010318-095138, 2019. a, b
Fer, I., Kelly, R., Moorcroft, P. R., Richardson, A. D., Cowdery, E. M., and Dietze, M. C.: Linking big models to big data: efficient ecosystem model calibration through Bayesian model emulation, Biogeosciences, 15, 5801–5830, https://doi.org/10.5194/bg-15-5801-2018, 2018. a
Flynn, K. J.: Castles built on sand: dysfunctionality in plankton models and the inadequacy of dialogue between biologists and modellers, J. Plankton Res., 27, 1205–1210, https://doi.org/10.1093/plankt/fbi099, 2005. a
Gray, J. S., Shiu-sun, R., and Or, Y. Y.: Effects of hypoxia and organic enrichment on the coastal marine environment, Mar. Ecol. Prog. Ser., 238, 249–279, https://doi.org/10.3354/meps238249, 2002. a
Grieffies, S. M.: Elements of MOM4p1, GFDL Ocean Group Technical Report No. 6, NOAA/Geophysical Fluid Dynamics Laboratory, Version prepared on 16 December 2009, 444 pp., 2009. a
Hagan, M. T. and Menhaj, M. B.: Training Feedforward Networks with the Marquardt Algorithm, IEEE T. Neuronal Network., 5, 989–993, https://doi.org/10.1109/72.329697, 1994. a
Hagan, M. T., Demuth, H. B., and Beale: Neural Network Design, PWS Publishing, Boston, MA, 1996. a
Herzfeld, M., Schmidt, M., Griffies, S. M., and Liang, Z.: Realistic test
cases for limited area ocean modelling, Ocean Model., 37, 1–34, https://doi.org/10.1016/j.ocemod.2010.12.008. a, b
Hofmann, A. F., Peltzer, E. T., Walz, P. M., and Brewer, P. G.: Hypoxia by
degrees: Establishing definitions for a changing ocean, Deep-Sea Res. Pt. I, 58, 1212–1226, https://doi.org/10.1016/j.dsr.2011.09.004, 2011. a
Holtermann, P. L., Umlauf, L., Tanhua, T., Schmale, O., Rehder, G., and Waniek, J. J.: The Baltic Sea Tracer Release Experiment: 1. Mixing rates, J. Geophys. Res., 117, C01021, https://doi.org/10.1029/2011JC007439, 2012. a, b, c
Hoppe, H.-G., Giesenhagen, H. C., Koppe, R., Hansen, H.-P., and Gocke, K.: Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea, Biogeosciences, 10, 4529–4546, https://doi.org/10.5194/bg-10-4529-2013, 2013. a, b, c
Hunke, E. C. and Dukowicz, J. K.: An Elastic-Viscous-Plastic Model for Sea Ice Dynamics, J. Phys. Oceanogr., 27, 1849–1867, https://doi.org/10.1175/1520-0485(1997)027<1849:AEVPMF>2.0.CO;2, 1997. a
Jensen, T. G.: Open boundary conditions in stratified ocean models, J. Marine Syst., 16, 297–322, https://doi.org/10.1016/S0924-7963(97)00023-7, 1998. a, b
Jonsson, P., Carman, R., and Wulff, F.: Laminated sediments in the Baltic: a tool for evaluating nutrient mass balances, Ambio, 19, 15–158, 1990. a
Karstensen, J., Liblik, T., Fischer, J., Bumke, K., and Krahmann, G.: Summer upwelling at the Boknis Eck time-series station (1982 to 2012) – a combined glider and wind data analysis, Biogeosciences, 11, 3603–3617, https://doi.org/10.5194/bg-11-3603-2014, 2014. a
Large, W. G., McWillimas, J. C., and Doney, S. C.: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization, Rev. Geophys., 363–403, https://doi.org/10.1029/94RG01872, 1994. a
Lehmann, A. and Myrberg, K.: Upwelling in the Baltic Sea – A review, J. Marine Syst., 74, S3–S12, https://doi.org/10.1016/j.jmarsys.2008.02.010, 2008. a, b
Lehmann, A., Hinrichsen, H.-H., Getzlaff, K., and Myrberg, K.: Quantifying the heterogeneity of hypoxic and anoxic areas in the Baltic Sea by a simplified coupled hydrodynamic-oxygen consumption model approach, J. Marine Syst., 134, 20–28, https://doi.org/10.1016/j.jmarsys.2014.02.012, 2014. a
Lennartz, S. T., Lehmann, A., Herrford, J., Malien, F., Hansen, H.-P., Biester, H., and Bange, H. W.: Long-term trends at the Boknis Eck time series station (Baltic Sea), 1957–2013: does climate change counteract the decline in eutrophication?, Biogeosciences, 11, 6323–6339, https://doi.org/10.5194/bg-11-6323-2014, 2014. a, b, c, d, e
Liu, S., Zhao, L., Xiao, C., Fan, W., Cai, Y., Pan, Y., and Chen, Y.: Review of Artificial Downwelling for Mitigating Hypoxia in Coastal Waters, Water, 12, 2846, https://doi.org/10.3390/w12102846. a, b, c
Löptien, U. and Dietze, H.: Effects of parameter indeterminacy in pelagic
biogeochemical modules of Earth System Models on projections into a warming
future: The scale of the problem, Global Biogeochem. Cy. 31, 1155–1172,
https://doi.org/10.1002/2017GB005690, 2017. a
Löptien, U. and Dietze, H.: Reciprocal bias compensation and ensuing uncertainties in model-based climate projections: pelagic biogeochemistry versus ocean mixing, Biogeosciences, 16, 1865–1881, https://doi.org/10.5194/bg-16-1865-2019, 2019. a
Makridakis, S., Spiliotis, E., and Assimakopoulos, V.: Statistical and Machine Learning forecasting methods: Concerns and ways forward, PLoS ONE, 13, 3, e0194889, https://doi.org/10.1371/journal.pone.0194889, 2018. a
Marlow, J.: Strömungsanalyse in einem ultra-hochaufgelösten Modell der
Eckernförder Bucht, Bachelor Thesis CAU, 1–51, 2020. a
Marquardt, D. W.: An Algorithm for Least-Squares Estimation of nonlinear Parameters, J. Soc. Ind. Appl. Math., 11, 431–441, https://doi.org/10.1137/0111030, 1963. a
Matthäus, W.: The history of investigation of salt water inflows into the Baltic Sea – from the early beginning to recent results, Mar. Sci. Rep. 65, Baltic Sea Res. Inst., Rostock-Warnemünde, Germany, 2006. a
Meier, H. M., Andersson, H. C., Eilola, K., Gustafsson, B. G., Kuznetsov, I.,
Müller-Karulis, B., Neumann, T., and Savchuk, O. P.: Hypoxia in future
climates: A model ensemble study for the Baltic Sea, Geophys. Res. Lett., 38, L24608,
https://doi.org/10.1029/2011GL049929, 2011. a
Meier, H. E. M., Hordoir, R., Andersson, H. C., Dietrich, C., Eilola, K.,
Gustafsson, B. G., Höglund, A., and Schimanke, S.: Modeling the combined impact of changing climate and changing nutrient loads on the Baltic Sea environment in an ensemble of transient simulations for 1961–2099, Clim. Dynam., 39, 2421–2441, https://doi.org/10.1007/s00382-012-1339-7, 2012. a
Meier, M., Dieterich, C., and Gröger, M.: Natural variability is a large
source of uncertainty in future projections of hypoxia in the Baltic Sea,
Communications Earth and Environment, 2, 50, https://doi.org/10.1038/s43247-021-00115-9,
2021. a, b
Naqvi, S. W. A., Bange, H. W., Farías, L., Monteiro, P. M. S., Scranton, M. I., and Zhang, J.: Marine hypoxia/anoxia as a source of CH4 and N2O, Biogeosciences, 7, 2159–2190, https://doi.org/10.5194/bg-7-2159-2010, 2010. a, b
Noffke, A., Sommer, S., Dale, A. W., Hall, P. O. J., and Pfannkuche, O.: Benthic nutrient fluxes in the Eastern Gotland Basin (Baltic Sea) with particular focus on microbial mat ecosystems, J. Marine Syst., 158, 1–12, https://doi.org/10.1016/j.jmarsys.2016.01.007, 2016. a
Pers, C. and Rahm, L.: Changes in apparent oxygen removal in the Baltic proper deep water, J. Marine Syst., 25, 421–429, https://doi.org/10.1016/S0924-7963(00)00031-2, 2000. a
Petenati, T.: Sauerstoffmangel im bodennahen Wasser der westlichen Ostsee, Landesamt für Natur und Umwelt des Landes Schleswig-Holstein, Germany, 1–8, 2017. a
Rahm, L.: Oxygen consumption in the Baltic proper, Limnol. Oceanogr., 32, 973–978, 1987. a
Reichstein, M., Camps-Valls, G., Stevens, B., Jung, M., Denzler, J., Carvalhais, N., and Prabhat: Deep learning and process understanding for data-driven Earth system science, Nature, 566, 195–204, https://doi.org/10.1038/s41586-019-0912-1, 2019. a
Samuelsson, P., Gollvik S., Kupiainen M., Kourzeneva E., and van de Berg, W. J.: The surface processes of the Rossby Centre regional atmospheric climate model (RCA4), SMHI-Report Meteorology, 157, 1–58, 2015. a
Samuelsson, P., Jones, C. G., Willen, U., Ullerstig, A., Gollvik, S., Hansson, U., Jansson. E., Kjellström, E., Nikulin, G., and Wyser, K.: The Rossby Centre Regional Climate model RCA3; Model description and performance, Tellus A, 63, 4–23, https://doi.org/10.1111/j.1600-0870.2010.00478.x, 2016. a
Sbalzarini, I. F., Theriot, J., and Koumoutsakos, P.: Machine Learning for Biological Trajectory Classification Applications, in: Proceedings of the CTR summer program, Center for Turbulence Research, 2002. a
Shapiro, R.: Smoothing, filtering, and boundary effects, Rev. Geophys., 8, 359–387, https://doi.org/10.1029/RG008i002p00359, 1970. a
Smetacek, V.: The Annual Cycle of Kiel Plankton: A Long-term Analysis, Estuaries, 8, 145–157, https://doi.org/10.2307/1351864, 1985. a, b, c
Stigebrandt, A. and Kalen, O.: Improving oxygen conditions in the deeper
parts of Bornholm Sea by pumped injection of winter water, Ambio, 42, 587–595,
https://doi.org/10.1007/s13280-012-0356-4, 2013. a
Stigebrandt, A., Rosenberg, R., Råman Vinnå, L., and Ödalen, M.: Consequences of artificial deepwater ventilation in the Bornholm Basin for oxygen conditions, cod reproduction and benthic biomass – a model study, Ocean Sci., 11, 93–110, https://doi.org/10.5194/os-11-93-2015, 2015. a
Zillén, L, Conley, D. J., Andren, T., Andren, E., and Gjorck. S.: Past
occurrences of hypoxia in the Baltic Sea andthe role of climate variability,
environmental change and human impact, Earth Sci. Rev., 91, 77–92, 2008. a
Short summary
In recent years fish-kill events caused by oxygen deficit have been reported in Eckernförde Bight (Baltic Sea). This study sets out to understand the processes causing respective oxygen deficits by combining high-resolution coupled ocean circulation biogeochemical modeling, monitoring data, and artificial intelligence.
In recent years fish-kill events caused by oxygen deficit have been reported in Eckernförde...
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