Articles | Volume 17, issue 10
https://doi.org/10.5194/bg-17-2875-2020
© Author(s) 2020. 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-17-2875-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
29 May 2020
Research article |
| 29 May 2020
| 29 May 2020
Wind-driven stratification patterns and dissolved oxygen depletion off the Changjiang (Yangtze) Estuary
Taavi Liblik
State Key Laboratory of Marine Geology, Tongji University, Shanghai,
200092, China
Department of Marine Systems, Tallinn University of Technology,
Tallinn, 12618, Estonia
Yijing Wu
State Key Laboratory of Marine Geology, Tongji University, Shanghai,
200092, China
Daidu Fan
CORRESPONDING AUTHOR
State Key Laboratory of Marine Geology, Tongji University, Shanghai,
200092, China
Laboratory of Marine Geology, Qingdao National Laboratory for Marine
Science and Technology, 387P+WW Shinan, Qingdao, Shandong, China
Dinghui Shang
State Key Laboratory of Marine Geology, Tongji University, Shanghai,
200092, China
Related authors
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Taavi Liblik, Germo Väli, Inga Lips, Madis-Jaak Lilover, Villu Kikas, and Jaan Laanemets
Ocean Sci., 16, 1475–1490, https://doi.org/10.5194/os-16-1475-2020, https://doi.org/10.5194/os-16-1475-2020, 2020
Short summary
Short summary
The upper mixed layer, shallower than the depth of the euphotic zone, is one of the preconditions for enhanced primary production in the ocean. In the Baltic Sea, the general understanding is that the upper mixed layer is much deeper in winter. In this study, we demonstrate that wintertime shallow stratification and an elevated phytoplankton biomass proxy, chlorophyll, are common in the Gulf of Finland. Stratification is invoked by the westward flow of riverine water forced by an easterly wind.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Taavi Liblik, Germo Väli, Inga Lips, Madis-Jaak Lilover, Villu Kikas, and Jaan Laanemets
Ocean Sci., 16, 1475–1490, https://doi.org/10.5194/os-16-1475-2020, https://doi.org/10.5194/os-16-1475-2020, 2020
Short summary
Short summary
The upper mixed layer, shallower than the depth of the euphotic zone, is one of the preconditions for enhanced primary production in the ocean. In the Baltic Sea, the general understanding is that the upper mixed layer is much deeper in winter. In this study, we demonstrate that wintertime shallow stratification and an elevated phytoplankton biomass proxy, chlorophyll, are common in the Gulf of Finland. Stratification is invoked by the westward flow of riverine water forced by an easterly wind.
Related subject area
Biogeochemistry: Coastal Ocean
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)
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Variability and drivers of carbonate chemistry at shellfish aquaculture sites in the Salish Sea, British Columbia
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters
Variable contribution of wastewater treatment plant effluents to nitrous oxide emission
Technical note: Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP)
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
The Northeast Greenland shelf as a late-summer CO2 source to the atmosphere
A comprehensive assessment of electrochemical ocean alkalinity enhancement in seawater: kinetics, efficiency, and precipitation thresholds
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
Dissolved Nitric Oxide in the Lower Elbe Estuary and the Hamburg Port Area
Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords
Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
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
The estimates of carbon sequestration potential in an expanding Arctic fjord affected by dark plumes of glacial meltwater (Hornsund, Svalbard)
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
Production and accumulation of reef framework by calcifying corals and macroalgae on a remote Indian Ocean cay
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
Significant nutrient consumption in the dark subsurface layer during a diatom bloom: a case study on Funka Bay, Hokkaido, Japan
Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
Sediment quality assessment in an industrialized Greek coastal marine area (western Saronikos Gulf)
Limits and CO2 equilibration of near-coast alkalinity enhancement
Role of phosphorus in the seasonal deoxygenation of the East China Sea shelf
Interannual variability of the initiation of the phytoplankton growing period in two French coastal ecosystems
Spatio-temporal distribution, photoreactivity and environmental control of dissolved organic matter in the sea-surface microlayer of the eastern marginal seas of China
Metabolic alkalinity release from large port facilities (Hamburg, Germany) and impact on coastal carbon storage
A Numerical reassessment of the Gulf of Mexico carbon system in connection with the Mississippi River and global ocean
Amanda Y. L. Cheong, Kogila Vani Annammala, Ee Ling Yong, Yongli Zhou, Robert S. Nichols, and Patrick Martin
Biogeosciences, 21, 2955–2971, https://doi.org/10.5194/bg-21-2955-2024, https://doi.org/10.5194/bg-21-2955-2024, 2024
Short summary
Short summary
We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
Short summary
Short summary
In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
Short summary
Short summary
Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
Short summary
Short summary
This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
Short summary
Short summary
Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
Short summary
Short summary
Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
Short summary
Short summary
Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
Short summary
Short summary
We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
Short summary
Short summary
The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
Short summary
Short summary
The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
Short summary
Short summary
Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
Short summary
Short summary
The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
EGUsphere, https://doi.org/10.5194/egusphere-2024-638, https://doi.org/10.5194/egusphere-2024-638, 2024
Short summary
Short summary
Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to treating nitrogen in WWTPs.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
EGUsphere, https://doi.org/10.5194/egusphere-2024-692, https://doi.org/10.5194/egusphere-2024-692, 2024
Short summary
Short summary
Ocean Alkalinity Enhancement (OAE) is an emerging marine CO2 removal method but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual on the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
Short summary
Short summary
Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
Short summary
Short summary
Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
Short summary
Short summary
The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
Short summary
Short summary
Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Esdoorn Willcox, Marcos Lemes, Thomas Juul-Pedersen, Mikael Kristian Sejr, Johnna Michelle Holding, and Søren Rysgaard
EGUsphere, https://doi.org/10.5194/egusphere-2024-6, https://doi.org/10.5194/egusphere-2024-6, 2024
Short summary
Short summary
For this work we measured the chemistry of seawater from bottles obtained from different depths, lon- and latitudes 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 and discuss what variables may be related to such changes.
Mallory Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan Carter, and Matthew Eisaman
EGUsphere, https://doi.org/10.5194/egusphere-2024-108, https://doi.org/10.5194/egusphere-2024-108, 2024
Short summary
Short summary
Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Preliminary results show CO2 equilibration occurred on 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.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
Short summary
Short summary
We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Tsuneo Ono, Daisuke Muraoka, Masahiro Hayashi, Makiko Yorifuji, Akihiro Dazai, Shigeyuki Omoto, Takehiro Tanaka, Tomohiro Okamura, Goh Onitsuka, Kenji Sudo, Masahiko Fujii, Ryuji Hamanoue, and Masahide Wakita
Biogeosciences, 21, 177–199, https://doi.org/10.5194/bg-21-177-2024, https://doi.org/10.5194/bg-21-177-2024, 2024
Short summary
Short summary
We carried out parallel year-round observations of pH and related parameters in five stations around the Japan coast. It was found that short-term acidified situations with Omega_ar less than 1.5 occurred at four of five stations. Most of such short-term acidified events were related to the short-term low salinity event, and the extent of short-term pH drawdown at high freshwater input was positively correlated with the nutrient concentration of the main rivers that flow into the coastal area.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
EGUsphere, https://doi.org/10.5194/egusphere-2023-3009, https://doi.org/10.5194/egusphere-2023-3009, 2023
Short summary
Short summary
Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. We found that the lower Elbe Estuary and the Hamburg Port area were a source of atmospheric NO. Our results suggest that NO in the lower Elbe Estuary was produced during nitrification, whereas NO in the Hamburg Port area was produced during nitrifier-denitrification.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
Short summary
Short summary
Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Hannah Sharpe, Michel Gosselin, Catherine Lalande, Alexandre Normandeau, Jean-Carlos Montero-Serrano, Khouloud Baccara, Daniel Bourgault, Owen Sherwood, and Audrey Limoges
Biogeosciences, 20, 4981–5001, https://doi.org/10.5194/bg-20-4981-2023, https://doi.org/10.5194/bg-20-4981-2023, 2023
Short summary
Short summary
We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.
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
Short summary
Short summary
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
Short summary
Short summary
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.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-162, https://doi.org/10.5194/bg-2023-162, 2023
Revised manuscript accepted for BG
Short summary
Short summary
European Arctic experiences rapid regional warming resulting in the retreat of glaciers terminating in the sea onto land. Due to this process, area of one of the well-studied fjords, Hornsund, increased by 100 km2 and 38 %. Using improved mathematical model, we estimated that despite some negative consequences of glacial meltwater release such newly ice-free area markedly contribute to atmospheric carbon uptake and become efficient carbon sinks.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Coline Poppeschi, Guillaume Charria, Anne Daniel, Romaric Verney, Peggy Rimmelin-Maury, Michaël Retho, Eric Goberville, Emilie Grossteffan, and Martin Plus
Biogeosciences, 19, 5667–5687, https://doi.org/10.5194/bg-19-5667-2022, https://doi.org/10.5194/bg-19-5667-2022, 2022
Short summary
Short summary
This paper aims to understand interannual changes in the initiation of the phytoplankton growing period (IPGP) in the current context of global climate changes over the last 20 years. An important variability in the timing of the IPGP is observed with a trend towards a later IPGP during this last decade. The role and the impact of extreme events (cold spells, floods, and wind burst) on the IPGP is also detailed.
Lin Yang, Jing Zhang, Anja Engel, and Gui-Peng Yang
Biogeosciences, 19, 5251–5268, https://doi.org/10.5194/bg-19-5251-2022, https://doi.org/10.5194/bg-19-5251-2022, 2022
Short summary
Short summary
Enrichment factors of dissolved organic matter (DOM) in the eastern marginal seas of China exhibited a significant spatio-temporal variation. Photochemical and enrichment processes co-regulated DOM enrichment in the sea-surface microlayer (SML). Autochthonous DOM was more frequently enriched in the SML than terrestrial DOM. DOM in the sub-surface water exhibited higher aromaticity than that in the SML.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
Short summary
Short summary
Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Le Zhang and Z. George Xue
Biogeosciences, 19, 4589–4618, https://doi.org/10.5194/bg-19-4589-2022, https://doi.org/10.5194/bg-19-4589-2022, 2022
Short summary
Short summary
We adopt a high-resolution carbon model for the Gulf of Mexico (GoM) and calculate the decadal trends of important carbon system variables in the GoM from 2001 to 2019. The GoM surface CO2 values experienced a steady increase over the past 2 decades, and the ocean surface pH is declining. Although carbonate saturation rates remain supersaturated with aragonite, they show a slightly decreasing trend. The northern GoM is a stronger carbon sink than we thought.
Cited articles
Altieri, A. H. and Gedan, K. B.: Climate change and dead zones, Glob. Change
Biol., 21, 1395–1406, https://doi.org/10.1111/gcb.12754, 2015.
Association for the Physical Sciences of the Sea: 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.
Bailey, K., Steinberg, C., Davies, C., Galibert, G., Hidas, M., McManus, M.
A., Murphy, T., Newton, J., Roughan, M., and Schaeffer, A.: Coastal Mooring
Observing Networks and Their Data Products: Recommendations for the Next
Decade, Front. Mar. Sci., 6, 180, https://doi.org/10.3389/fmars.2019.00180, 2019.
Beardsley, R. C., Limeburner, R., Yu, H., and Cannon, G. A.: Discharge of the
Changjiang (Yangtze River) into the East China Sea, Cont. Shelf Res.,
4, 57–76, https://doi.org/10.1016/0278-4343(85)90022-6, 1985.
Chang, D., Zhang, F., and Edwards, C. R.: Real-time guidance of underwater
gliders assisted by predictive ocean models, J. Atmos. Ocean. Tech.,
32, 562–578, https://doi.org/10.1175/JTECH-D-14-00098.1, 2015.
Chen, J., Pan, D., Liu, M., Mao, Z., Zhu, Q., Chen, N., Zhang, X., and Tao,
B.: Relationships Between Long-Term Trend of Satellite-Derived Chlorophyll-a
and Hypoxia Off the Changjiang Estuary, Estuar. Coast., 40,
1055–1065, https://doi.org/10.1007/s12237-016-0203-0, 2017.
Chen, Y.-L. L., Chen, H.-Y., Gong, G.-C., Lin, Y.-H., Jan, S., and Takahashi,
M.: Phytoplankton production during a summer coastal upwelling in the East
China Sea, Cont. Shelf Res., 24, 1321–1338, https://doi.org/10.1016/j.csr.2004.04.002,
2004.
Chu, P., Yuchun, C., and Kuninaka, A.: Seasonal variability of the Yellow
Sea/East China Sea surface fluxes and thermohaline structure, Adv. Atmos.
Sci., 22, 1–20, https://doi.org/10.1007/BF02930865, 2005.
Conley, D. J., Björck, S., Bonsdorff, E., Carstensen, J.,
Destouni, G., Gustafsson, B. G., Hietanen, S., Kortekaas, M., Kuosa, H.,
Markus Meier, H. E., Müller-Karulis, B., Nordberg, K.,
Norkko, A., Nürnberg, G., Pitkänen,
H., Rabalais, N. N., Rosenberg, R., Savchuk, O. P., Slomp, C. P., Voss, M.,
Wulff, F., and Zillén, L.: Hypoxia-Related Processes in the Baltic Sea,
Environ. Sci. Technol., 43, 3412–3420, https://doi.org/10.1021/es802762a, 2009.
Csanady, G. T.: Circulation in the Coastal Ocean, Adv. Geophys., 23,
101–183, https://doi.org/10.1016/S0065-2687(08)60331-3, 1981.
Cui, Y., Wu, J., Ren, J., and Xu, J.: Physical dynamics structures and oxygen
budget of summer hypoxia in the Pearl River Estuary, Limnol. Oceanogr.,
64, 131–148, https://doi.org/10.1002/lno.11025, 2019.
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.
Fofonoff, N. P. and Millard Jr., R. C.: Algorithms for the computation of
fundamental properties of seawater, UNESCO, available at: https://www.oceanbestpractices.net/handle/11329/109 (last access: 30 August 2019), 1983.
Fong, D. A. and Geyer, W. R.: The Alongshore Transport of Freshwater in a
Surface-Trapped River Plume*, J. Phys. Oceanogr., 32, 957–972,
https://doi.org/10.1175/1520-0485(2002)032<0957:TATOFI>2.0.CO;2,
2002.
Große, F., Fennel, K., Zhang, H., and Laurent, A.: Quantifying the contributions of riverine vs. oceanic nitrogen to hypoxia in the East China Sea, Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-342, in review, 2019.
Guo, Y., Rong, Z., Li, B., Xu, Z., Li, P., and Li, X.: Physical processes
causing the formation of hypoxia off the Changjiang estuary after Typhoon
Chan-hom, 2015, J. Oceanol. Limnol., 37, 1–17,
https://doi.org/10.1007/s00343-019-7336-5, 2019.
Horner-Devine, A. R.: The bulge circulation in the Columbia River plume,
Cont. Shelf Res., 29, 234–251, https://doi.org/10.1016/j.csr.2007.12.012, 2009.
Hu, J. and Wang, X. H.: Progress on upwelling studies in the China seas,
Rev. Geophys., 54, 653–673, https://doi.org/10.1002/2015RG000505, 2016.
Hung, C.-C., Chung, C.-C., Gong, G.-C., Jan, S., Tsai, Y., Chen, K.-S.,
Chou, W. C., Lee, M.-A., Chang, Y., Chen, M.-H., Yang, W.-R., Tseng, C.-J.,
and Gawarkiewicz, G.: Nutrient supply in the Southern East China Sea after
Typhoon Morakot, J. Mar. Res., 71, 133–149,
https://doi.org/10.1357/002224013807343425, 2013.
Kang, Y., Pan, D., Bai, Y., He, X., Chen, X., Chen, C.-T. A., and Wang, D.:
Areas of the global major river plumes, Acta Oceanol. Sin., 32, 79–88,
https://doi.org/10.1007/s13131-013-0269-5, 2013.
Large, W. G. and Pond, S.: Open Ocean Momentum Flux Measurements in Moderate
to Strong Winds, J. Phys. Oceanogr., 11, 324–336,
https://doi.org/10.1175/1520-0485(1981)011<0324:OOMFMI>2.0.CO;2,
1981.
Lentz, S. J. and Helfrich, K. R.: Buoyant gravity currents along a sloping
bottom in a rotating fluid, J. Fluid Mech, 464, 251–278,
https://doi.org/10.1017/S0022112002008868, 2002.
Li, D., Jing, Z., Daji, H., Ying, W., and Jun, L.: Oxygen depletion off the
Changjiang (Yangtze River) Estuary, Sci. China Ser. D, 45, 1137–1146, https://doi.org/10.1360/02yd9110, 2002.
Li, L., He, Z., Xia, Y., and Dou, X.: Dynamics of sediment transport and
stratification in Changjiang River Estuary, China, Estuar. Coast. Shelf
S., 213, 1–17, https://doi.org/10.1016/J.ECSS.2018.08.002, 2018.
Li, M. and Chen, Z.: An Assessment of Saltwater Intrusion in the Changjiang
(Yangtze) River Estuary, China, Coasts and Estuaries, 31–43,
https://doi.org/10.1016/B978-0-12-814003-1.00002-2, 2019.
Li, M. and Rong, Z.: Effects of tides on freshwater and volume transports in
the Changjiang River plume, J. Geophys. Res., 117, 6027,
https://doi.org/10.1029/2011JC007716, 2012.
Li, Y. L.: Seasonal Hypoxia and its Affecting Factors in the Yangtze River
Estuary, Ocean University of China, Qingdao, 2015 (in Chinese).
Li, Z., Song, S., Li, C., and Yu, Z.: The sinking of the phytoplankton
community and its contribution to seasonal hypoxia in the Changjiang
(Yangtze River) estuary and its adjacent waters, Estuar. Coast. Shelf S.,
208, 170–179, https://doi.org/10.1016/J.ECSS.2018.05.007, 2018.
Liblik, T., Karstensen, J., Testor, P., Alenius, P., Hayes, D., Ruiz, S.,
Heywood, K. J., Pouliquen, S., Mortier, L., and Mauri, E.: Potential for an
underwater glider component as part of the Global Ocean Observing System,
Methods Oceanogr., 17, 50–82, https://doi.org/10.1016/j.mio.2016.05.001, 2016.
Lie, H.-J. and Cho, C.-H.: Recent advances in understanding the circulation
and hydrography of the East China Sea, Fish. Oceanogr., 11, 318–328,
https://doi.org/10.1046/j.1365-2419.2002.00215.x, 2002.
Lie, H.-J. and Cho, C.-H.: Seasonal circulation patterns of the Yellow and
East China Seas derived from satellite-tracked drifter trajectories and
hydrographic observations, Prog. Oceanogr., 146, 121–141,
https://doi.org/10.1016/J.POCEAN.2016.06.004, 2016.
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, 2016.
Liu, W., Song, J., Huamao, Y., Li, N., Xuegang, L. I., and Liqin, D.:
Dissolved barium as a tracer of Kuroshio incursion in the Kuroshio region
east of Taiwan Island and the adjacent East China Sea, Sci. China Earth
Sci., 60, 1356–1367, https://doi.org/10.1007/s11430-016-9039-7, 2017.
Meissner, T., Wentz, F. J., and Manaster, A.: Remote Sensing Systems SMAP
Ocean Surface Salinities [Level 2C, Level 3 Running 8-day, Level 3 Monthly],
Version 3.0 validated release, Remote Sensing Systems, Santa Rosa, CA, USA, https://doi.org/10.5067/SMP3A-3SPCS, 2018.
Moon, J.-H., Kim, T., Son, Y. B., Hong, J.-S., Lee, J.-H., Chang, P.-H., and
Kim, S.-K.: Contribution of low-salinity water to sea surface warming of the
East China Sea in the summer of 2016, Prog. Oceanogr., 175, 68–80,
https://doi.org/10.1016/j.pocean.2019.03.012, 2019.
Ni, X., Huang, D., Zeng, D., Zhang, T., Li, H., and Chen, J.: The impact of
wind mixing on the variation of bottom dissolved oxygen off the Changjiang
Estuary during summer, J. Marine Syst., 154, 122–130,
https://doi.org/10.1016/j.jmarsys.2014.11.010, 2016.
Ning, X., Lin, C., Su, J., Liu, C., Hao, Q., and Le, F.: Long-term changes of
dissolved oxygen, hypoxia, and the responses of the ecosystems in the East
China Sea from 1975 to 1995, J. Oceanogr., 67, 59–75,
https://doi.org/10.1007/s10872-011-0006-7, 2011.
Obenour, D. R., Scavia, D., Rabalais, N. N., Turner, R. E., and Michalak, A.
M.: Retrospective Analysis of Midsummer Hypoxic Area and Volume in the
Northern Gulf of Mexico, 1985–2011, Environ. Sci. Technol., 47,
9808–9815, https://doi.org/10.1021/es400983g, 2013.
Peng, L., Benwei, S., Yaping, W., Weihua, Q., Yangang, L., and Jian, C.:
Analysis of the characteristics of offshore currents in the Changjiang
(Yangtze River) estuarine waters based on buoy observations, Acta Oceanol.
Sin., 36, 13–20, https://doi.org/10.1007/s13131-017-0973-7, 2017.
Qian, W., Dai, M., Xu, M., Kao, S. ji, Du, C., Liu, J., Wang, H., Guo, L.,
and Wang, L.: Non-local drivers of the summer hypoxia in the East China Sea
off the Changjiang Estuary, Estuar. Coast. Shelf S., 198, 393–399,
https://doi.org/10.1016/j.ecss.2016.08.032, 2017.
Ren, F., Fan, D., Wu, Y., and Zhao, Q.: The evolution of hypoxia off the
Changjiang Estuary in the last 3000 years: Evidence from benthic
foraminifera and elemental geochemistry, Mar. Geol., 417, 106039,
https://doi.org/10.1016/J.MARGEO.2019.106039, 2019.
Rudnick, D. L.: Ocean Research Enabled by Underwater Gliders, Annu. Rev. Mar.
Sci., 8, 519–541, https://doi.org/10.1146/annurev-marine-122414-033913, 2016.
Sun, H., Yang, Q., Zhao, W., Liang, X., and Tian, J.: Temporal variability of
diapycnal mixing in the northern South China Sea, J. Geophys. Res.-Ocean.,
121, 8840–8848, https://doi.org/10.1002/2016JC012044, 2016.
Testa, J. M. and Kemp, W. M.: Spatial and Temporal Patterns of
Winter–Spring Oxygen Depletion in Chesapeake Bay Bottom Water, Estuaries
and Coasts, 37, 1432–1448, https://doi.org/10.1007/s12237-014-9775-8, 2014.
Tseng, Y.-F., Lin, J., Dai, M., and Kao, S.-J.: Joint effect of freshwater plume and coastal upwelling on phytoplankton growth off the Changjiang River, Biogeosciences, 11, 409–423, https://doi.org/10.5194/bg-11-409-2014, 2014.
Vaquer-Sunyer, R. and Duarte, C. M.: Thresholds of hypoxia for marine
biodiversity, P. Natl. Acad. Sci. USA, 105, 15452–15457,
https://doi.org/10.1073/pnas.0803833105, 2008.
Venkatesan, R., Lix, J. K., Phanindra Reddy, A., Arul Muthiah, M., and
Atmanand, M. A.: Two decades of operating the Indian moored buoy network:
significance and impact, J. Oper. Oceanogr., 9, 45–54,
https://doi.org/10.1080/1755876X.2016.1182792, 2016.
Wang, B. and Wang, X.: Chemical hydrography of coastal upwelling in the East
China Sea, Chin. J. Oceanol. Limn., 25, 16–26,
https://doi.org/10.1007/s00343-007-0016-x, 2007.
Wang, B., Wei, Q., Chen, J., and Xie, L.: Annual cycle of hypoxia off the
Changjiang (Yangtze River) Estuary, Mar. Environ. Res., 77, 1–5,
https://doi.org/10.1016/j.marenvres.2011.12.007, 2012.
Wang, B., Chen, J., Jin, H., Li, H., Huang, D., and Cai, W.-J.: Diatom
bloom-derived bottom water hypoxia off the Changjiang estuary, with and
without typhoon influence, Limnol. Oceanogr., 62, 1552–1569,
https://doi.org/10.1002/lno.10517, 2017.
Wang, H., Dai, M., Liu, J., Kao, S.-J., Zhang, C., Cai, W.-J., Wang, G.,
Qian, W., Zhao, M., and Sun, Z.: Eutrophication-Driven Hypoxia in the East
China Sea off the Changjiang Estuary, Environ. Sci. Technol., 50,
2255–2263, https://doi.org/10.1021/acs.est.5b06211, 2016.
Wei, Q., Wang, B., Yu, Z., Chen, J., and Xue, L.: Mechanisms leading to the
frequent occurrences of hypoxia and a preliminary analysis of the associated
acidification off the Changjiang estuary in summer, Sci. China Earth Sci.,
60, 360–381, https://doi.org/10.1007/s11430-015-5542-8, 2017a.
Wei, Q., Yu, Z., Wang, B., Wu, H., Sun, J., Zhang, X., Fu, M., Xia, C., and
Wang, H.: Offshore detachment of the Changjiang River plume and its
ecological impacts in summer, J. Oceanogr., 73, 277–294,
https://doi.org/10.1007/s10872-016-0402-0, 2017b.
Weiss, R. F.: The solubility of nitrogen, oxygen and argon in water and
seawater, Deep-Sea Res. Oceanogr. Abstr., 17, 721–735,
https://doi.org/10.1016/0011-7471(70)90037-9, 1970.
Wu, H., Deng, B., Yuan, R., Hu, J., Gu, J., Shen, F., Zhu, J., and Zhang, J.:
Detiding Measurement on Transport of the Changjiang-Derived Buoyant Coastal
Current, J. Phys. Oceanogr., 43, 2388–2399,
https://doi.org/10.1175/JPO-D-12-0158.1, 2013.
Wu, Y., Fan, D., Wang, D., and Yin, P.: Increasing hypoxia in the Changjiang
Estuary during the last three decades deciphered from sedimentary
redox-sensitive elements, Mar. Geol., 419, 106044,
https://doi.org/10.1016/J.MARGEO.2019.106044, 2019.
Xu, Q., Zhang, S., Cheng, Y., and Zuo, J.: Interannual Feature of Summer
Upwelling around the Zhoushan Islands in the East China Sea, J. Coastal Res.,
331, 125–134, https://doi.org/10.2112/JCOASTRES-D-15-00197.1, 2017.
Xu, Z., Ma, J., Wang, H., Hu, Y., Yang, G., Deng, W., Xu, Z., Ma, J., Wang,
H., Hu, Y., Yang, G., and Deng, W.: River Discharge and Saltwater Intrusion
Level Study of Yangtze River Estuary, China, Water, 10, 683,
https://doi.org/10.3390/w10060683, 2018.
Xuan, J.-L., Huang, D., Zhou, F., Zhu, X.-H., and Fan, X.: The role of wind
on the detachment of low salinity water in the Changjiang Estuary in summer,
J. Geophys. Res.-Oceans, 117, C10004, https://doi.org/10.1029/2012JC008121, 2012.
Yang, L., Chen, Z., Sun, Z., and Hu, J.: Sectional characteristics of
temperature, salinity and density off the central Zhejiang coast in the
spring of 2016, Acta Oceanol. Sin., 38, 175–182,
https://doi.org/10.1007/s13131-019-1421-7, 2019.
Ye, W., Zhang, G., Zhu, Z., Han, Y., Wang, L., and Sun, M.: Methane
distribution and sea-to-air flux in the East China Sea during the summer of
2013: Impact of hypoxia, Deep-Sea Res. Pt. II, 124,
74–83, https://doi.org/10.1016/J.DSR2.2015.01.008, 2016.
Zhang, J., Liu, S. M., Ren, J. L., Wu, Y., and Zhang, G. L.: Nutrient
gradients from the eutrophic Changjiang (Yangtze River) Estuary to the
oligotrophic Kuroshio waters and re-evaluation of budgets for the East China
Sea Shelf, Prog. Oceanogr., 74, 449–478,
https://doi.org/10.1016/j.pocean.2007.04.019, 2007.
Zhang, L., Liu, Z., Zhang, J., Hong, G. H., Park, Y., and Zhang, H. F.:
Reevaluation of mixing among multiple water masses in the shelf: An example
from the East China Sea, Cont. Shelf Res., 27, 1969–1979,
https://doi.org/10.1016/J.CSR.2007.04.002, 2007.
Zhang, W., Wu, H., and Zhu, Z.: Transient Hypoxia Extent Off Changjiang River
Estuary due to Mobile Changjiang River Plume, J. Geophys. Res.-Oceans,
123, 9196–9211, https://doi.org/10.1029/2018JC014596, 2018.
Zhang, W., Wu, H., Hetland, R. D., and Zhu, Z.: On Mechanisms Controlling the
Seasonal Hypoxia Hot Spots off the Changjiang River Estuary, J. Geophys.
Res.-Oceans, 124, 8683–8700, https://doi.org/10.1029/2019JC015322, 2019.
Zheng, J., Gao, S., Liu, G., Wang, H., and Zhu, X.: Modeling the impact of river discharge and wind on the hypoxia off Yangtze Estuary, Nat. Hazards Earth Syst. Sci., 16, 2559–2576, https://doi.org/10.5194/nhess-16-2559-2016, 2016.
Zhou, Z., Yu, R., Sun, C., Feng, M., and Zhou, M.: Impacts of Changjiang
River Discharge and Kuroshio Intrusion on the Diatom and Dinoflagellate
Blooms in the East China Sea, J. Geophys. Res.-Oceans, 124, 5244–5257,
https://doi.org/10.1029/2019JC015158, 2019.
Zhu, J., Zhu, Z., Lin, J., Wu, H., and Zhang, J.: Distribution of hypoxia and
pycnocline off the Changjiang Estuary, China, J. Marine Syst., 154, 28–40,
https://doi.org/10.1016/j.jmarsys.2015.05.002, 2016.
Zhu, Z.-Y., Zhang, J., Wu, Y., Zhang, Y.-Y., Lin, J., and Liu, S.-M.: Hypoxia
off the Changjiang (Yangtze River) Estuary: Oxygen depletion and organic
matter decomposition, Mar. Chem., 125, 108–116,
https://doi.org/10.1016/J.MARCHEM.2011.03.005, 2011.
Zhu, Z. Y., Wu, H., Liu, S. M., Wu, Y., Huang, D. J., Zhang, J., and Zhang,
G. Sen: Hypoxia off the Changjiang (Yangtze River) estuary and in the
adjacent East China Sea: Quantitative approaches to estimating the tidal
impact and nutrient regeneration, Mar. Pollut. Bull., 125, 103–114,
https://doi.org/10.1016/j.marpolbul.2017.07.029, 2017.
Zuo, J., Song, J., Yuan, H., Li, X., Li, N., and Duan, L.: Impact of Kuroshio
on the dissolved oxygen in the East China Sea region, J. Oceanol. Limnol.,
37, 513–524, https://doi.org/10.1007/s00343-019-7389-5, 2019.
Short summary
Multiple factors have been accused of triggering coastal hypoxia off the Changjiang Estuary. In situ observations, remote sensing and numerical simulation data were used to study dissolved oxygen depletion in the area. Oxygen distributions can be explained by wind forcing and river discharge, as well as concurrent features in surface and deep layer circulation. If summer monsoon prevails, hypoxia more likely occurs in the north while hypoxia in the south appears if the summer monsoon is weaker.
Multiple factors have been accused of triggering coastal hypoxia off the Changjiang Estuary. In...
Altmetrics
Final-revised paper
Preprint