Articles | Volume 17, issue 10
https://doi.org/10.5194/bg-17-2701-2020
© 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-17-2701-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 May 2020
Research article |
| 19 May 2020
| 19 May 2020
Quantifying the contributions of riverine vs. oceanic nitrogen to hypoxia in the East China Sea
Department of Oceanography, Dalhousie University, Halifax, NS, Canada
Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
Katja Fennel
Department of Oceanography, Dalhousie University, Halifax, NS, Canada
Haiyan Zhang
Department of Oceanography, Dalhousie University, Halifax, NS, Canada
School of Marine Science and Technology, Tianjin University, Tianjin, China
Arnaud Laurent
Department of Oceanography, Dalhousie University, Halifax, NS, Canada
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We used the ECOHAM5 model to provide a consistent picture of the physical and biological drivers of oxygen deficiency in the North Sea. Regions susceptible to oxygen deficiency are characterised by low tidal mixing and moderate water depth (~ 40 m). Variations in upper layer productivity drive the year-to-year variability of bottom oxygen conditions. The model-based analysis reveals that benthic and pelagic remineralisation account for 90 % of bottom oxygen consumption observed at North Dogger.
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Fabian Große, Naomi Greenwood, Markus Kreus, Hermann-Josef Lenhart, Detlev Machoczek, Johannes Pätsch, Lesley Salt, and Helmuth Thomas
Biogeosciences, 13, 2511–2535, https://doi.org/10.5194/bg-13-2511-2016, https://doi.org/10.5194/bg-13-2511-2016, 2016
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A. Laurent, K. Fennel, R. Wilson, J. Lehrter, and R. Devereux
Biogeosciences, 13, 77–94, https://doi.org/10.5194/bg-13-77-2016, https://doi.org/10.5194/bg-13-77-2016, 2016
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In low oxygen environments, the lack of oxygen influences sediment biogeochemistry and in turn sediment-water fluxes. These nonlinear interactions are often missing from biogeochemical circulation models because sediment models are computationally expensive. A method for parameterizing realistic sediment-water fluxes is presented and applied to the Mississippi River Dead Zone where high primary production, stimulated by excess nutrient loads, promotes low bottom water conditions in summer.
L. Yu, K. Fennel, A. Laurent, M. C. Murrell, and J. C. Lehrter
Biogeosciences, 12, 2063–2076, https://doi.org/10.5194/bg-12-2063-2015, https://doi.org/10.5194/bg-12-2063-2015, 2015
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Our study suggests that a combination of physical processes and sediment oxygen consumption determine the spatial extent and temporal dynamics of hypoxia on the Louisiana shelf. In summer, stratification isolates oxygen-rich surface waters from hypoxic bottom waters; oxygen outgasses to the atmosphere at this time. A large fraction of primary production occurs below the pycnocline in summer, but this primary production does not strongly affect the spatial extent of hypoxic bottom waters.
K.-K. Liu, C.-K. Kang, T. Kobari, H. Liu, C. Rabouille, and K. Fennel
Biogeosciences, 11, 7061–7075, https://doi.org/10.5194/bg-11-7061-2014, https://doi.org/10.5194/bg-11-7061-2014, 2014
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Z. Xue, R. He, K. Fennel, W.-J. Cai, S. Lohrenz, and C. Hopkinson
Biogeosciences, 10, 7219–7234, https://doi.org/10.5194/bg-10-7219-2013, https://doi.org/10.5194/bg-10-7219-2013, 2013
W. J. Burt, H. Thomas, K. Fennel, and E. Horne
Biogeosciences, 10, 53–66, https://doi.org/10.5194/bg-10-53-2013, https://doi.org/10.5194/bg-10-53-2013, 2013
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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
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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.
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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.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha A. Siedlecki, and Dana J. Greeley
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-181, https://doi.org/10.5194/bg-2023-181, 2023
Revised manuscript accepted for BG
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We provide a new multi-stressor data product allowed us to characterize the seasonality of temperature, oxygen, and carbon dioxide in the southern Salish Sea and provided insight into impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also described the present-day frequencies of temperature, oxygen, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy, Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-153, https://doi.org/10.5194/bg-2023-153, 2023
Revised manuscript accepted for BG
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The coastal ocean in northeastern USA provides many services, including fisheries and habitat for threatened species. In summer 2019, a bloom occurred of an unusual large 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 maybe become more prevalent as the ocean warms due to climate change.
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.
Eleanor Simpson, Debby Ianson, Karen Elizabeth Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
EGUsphere, https://doi.org/10.5194/egusphere-2023-1553, https://doi.org/10.5194/egusphere-2023-1553, 2023
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Shellfish aquaculture operates in nearshore areas where data on key ocean acidification (OA) parameters is limited. We show daily and seasonal variability in chemical properties at nearshore aquaculture sites in Canada and define drivers of these changes. Nearshore locations have greater variability than open waters and uptake of carbon by phytoplankton is the major driver of variability. Areas with high primary productivity are recommended for aquaculture as they will be less vulnerable to OA.
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.
Claudine Hauri, Brita Irving, Sam Dupont, Remi Pages, Donna Hauser, and Seth Danielson
EGUsphere, https://doi.org/10.5194/egusphere-2023-1386, https://doi.org/10.5194/egusphere-2023-1386, 2023
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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.
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.
Charlotte Williams, Tom Hull, Matthew Palmer, Claire Mahaffey, Naomi Greenwood, Jan Kaiser, and Matthew Toberman
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-100, https://doi.org/10.5194/bg-2023-100, 2023
Revised manuscript accepted for BG
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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 reach ecologically low levels.
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.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Y. Chen, and Daniel Obrist
EGUsphere, https://doi.org/10.5194/egusphere-2023-720, https://doi.org/10.5194/egusphere-2023-720, 2023
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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. While belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
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.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio 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
EGUsphere, https://doi.org/10.5194/egusphere-2023-706, https://doi.org/10.5194/egusphere-2023-706, 2023
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The Patagonian fjord is one world region where low-oxygen water and hypoxia conditions is observed. An in-situ data set was used to quantify the mechanism involved in the presence of low-oxygen water and hypoxic 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.
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.
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
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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
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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
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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
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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.
Michael M. Whitney
Biogeosciences, 19, 4479–4497, https://doi.org/10.5194/bg-19-4479-2022, https://doi.org/10.5194/bg-19-4479-2022, 2022
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Coastal hypoxia is a major environmental problem of increasing severity. The 21st-century projections analyzed indicate global coastal waters will warm and experience rapid declines in oxygen. The forecasted median coastal trends for increasing sea surface temperature and decreasing oxygen capacity are 48 % and 18 % faster than the rates observed over the last 4 decades. Existing hypoxic areas are expected to worsen, and new hypoxic areas likely will emerge under these warming-related pressures.
Bryce Van Dam, Nele Lehmann, Mary A. Zeller, Andreas Neumann, Daniel Pröfrock, Marko Lipka, Helmuth Thomas, and Michael Ernst Böttcher
Biogeosciences, 19, 3775–3789, https://doi.org/10.5194/bg-19-3775-2022, https://doi.org/10.5194/bg-19-3775-2022, 2022
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We quantified sediment–water exchange at shallow sites in the North and Baltic seas. We found that porewater irrigation rates in the former were approximately twice as high as previously estimated, likely driven by relatively high bioirrigative activity. In contrast, we found small net fluxes of alkalinity, ranging from −35 µmol m−2 h−1 (uptake) to 53 µmol m−2 h−1 (release). We attribute this to low net denitrification, carbonate mineral (re-)precipitation, and sulfide (re-)oxidation.
Jiaying Abby Guo, Robert Strzepek, Anusuya Willis, Aaron Ferderer, and Lennart Thomas Bach
Biogeosciences, 19, 3683–3697, https://doi.org/10.5194/bg-19-3683-2022, https://doi.org/10.5194/bg-19-3683-2022, 2022
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Ocean alkalinity enhancement is a CO2 removal method with significant potential, but it can lead to a perturbation of the ocean with trace metals such as nickel. This study tested the effect of increasing nickel concentrations on phytoplankton growth and photosynthesis. We found that the response to nickel varied across the 11 phytoplankton species tested here, but the majority were rather insensitive. We note, however, that responses may be different under other experimental conditions.
Malcolm E. Scully, W. Rockwell Geyer, David Borkman, Tracy L. Pugh, Amy Costa, and Owen C. Nichols
Biogeosciences, 19, 3523–3536, https://doi.org/10.5194/bg-19-3523-2022, https://doi.org/10.5194/bg-19-3523-2022, 2022
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For two consecutive summers, the bottom waters in southern Cape Cod Bay became severely depleted of dissolved oxygen. Low oxygen levels in bottom waters have never been reported in this area before, and this unprecedented occurrence is likely the result of a new algae species that recently began blooming during the late-summer months. We present data suggesting that blooms of this new species are the result of regional climate change including warmer waters and changes in summer winds.
Zheng Chen, Bin Wang, Chuang Xu, Zhongren Zhang, Shiyu Li, and Jiatang Hu
Biogeosciences, 19, 3469–3490, https://doi.org/10.5194/bg-19-3469-2022, https://doi.org/10.5194/bg-19-3469-2022, 2022
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Deterioration of low-oxygen conditions in the coastal waters off Hong Kong was revealed by monitoring data over two decades. The declining wind forcing and the increasing nutrient input contributed significantly to the areal expansion and intense deterioration of low-oxygen conditions. Also, the exacerbated eutrophication drove a shift in the dominant source of organic matter from terrestrial inputs to in situ primary production, which has probably led to an earlier onset of hypoxia in summer.
Stella-Theresa Stoicescu, Jaan Laanemets, Taavi Liblik, Māris Skudra, Oliver Samlas, Inga Lips, and Urmas Lips
Biogeosciences, 19, 2903–2920, https://doi.org/10.5194/bg-19-2903-2022, https://doi.org/10.5194/bg-19-2903-2022, 2022
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Coastal basins with high input of nutrients often suffer from oxygen deficiency. In summer 2018, the extent of oxygen depletion was exceptional in the Gulf of Riga. We analyzed observational data and found that extensive oxygen deficiency appeared since the water layer close to the seabed, where oxygen is consumed, was separated from the surface layer. The problem worsens if similar conditions restricting vertical transport of oxygen occur more frequently in the future.
Justin C. Tiano, Jochen Depestele, Gert Van Hoey, João Fernandes, Pieter van Rijswijk, and Karline Soetaert
Biogeosciences, 19, 2583–2598, https://doi.org/10.5194/bg-19-2583-2022, https://doi.org/10.5194/bg-19-2583-2022, 2022
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This study gives an assessment of bottom trawling on physical, chemical, and biological characteristics in a location known for its strong currents and variable habitats. Although trawl gears only removed the top 1 cm of the seabed surface, impacts on reef-building tubeworms significantly decreased carbon and nutrient cycling. Lighter trawls slightly reduced the impact on fauna and nutrients. Tubeworms were strongly linked to biogeochemical and faunal aspects before but not after trawling.
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022, https://doi.org/10.5194/bg-19-2523-2022, 2022
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The concentration of the trace metal barium (Ba) in coastal seawater is a function of continental input, such as riverine discharge. Our geochemical records of the severely hot and dry year 2018, and following wet year 2019, reveal that prolonged drought imprints with exceptionally low Ba concentrations in benthic foraminiferal calcium carbonates of coastal sediments. This highlights the potential of benthic Ba / Ca to trace past climate extremes and variability in coastal marine records.
Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
Biogeosciences, 19, 2397–2415, https://doi.org/10.5194/bg-19-2397-2022, https://doi.org/10.5194/bg-19-2397-2022, 2022
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We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
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Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
Wiley Evans, Geoffrey T. Lebon, Christen D. Harrington, Yuichiro Takeshita, and Allison Bidlack
Biogeosciences, 19, 1277–1301, https://doi.org/10.5194/bg-19-1277-2022, https://doi.org/10.5194/bg-19-1277-2022, 2022
Short summary
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Information on the marine carbon dioxide system along the northeast Pacific Inside Passage has been limited. To address this gap, we instrumented an Alaskan ferry in order to characterize the marine carbon dioxide system in this region. Data over a 2-year period were used to assess drivers of the observed variability, identify the timing of severe conditions, and assess the extent of contemporary ocean acidification as well as future levels consistent with a 1.5 °C warmer climate.
Melissa Ward, Tye L. Kindinger, Heidi K. Hirsh, Tessa M. Hill, Brittany M. Jellison, Sarah Lummis, Emily B. Rivest, George G. Waldbusser, Brian Gaylord, and Kristy J. Kroeker
Biogeosciences, 19, 689–699, https://doi.org/10.5194/bg-19-689-2022, https://doi.org/10.5194/bg-19-689-2022, 2022
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Here, we synthesize the results from 62 studies reporting in situ rates of seagrass metabolism to highlight spatial and temporal variability in oxygen fluxes and inform efforts to use seagrass to mitigate ocean acidification. Our analyses suggest seagrass meadows are generally autotrophic and variable in space and time, and the effects on seawater oxygen are relatively small in magnitude.
Tianfei Xue, Ivy Frenger, A. E. Friederike Prowe, Yonss Saranga José, and Andreas Oschlies
Biogeosciences, 19, 455–475, https://doi.org/10.5194/bg-19-455-2022, https://doi.org/10.5194/bg-19-455-2022, 2022
Short summary
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The Peruvian system supports 10 % of the world's fishing yield. In the Peruvian system, wind and earth’s rotation bring cold, nutrient-rich water to the surface and allow phytoplankton to grow. But observations show that it grows worse at high upwelling. Using a model, we find that high upwelling happens when air mixes the water the most. Then phytoplankton is diluted and grows slowly due to low light and cool upwelled water. This study helps to estimate how it might change in a warming climate.
Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
Biogeosciences, 19, 295–312, https://doi.org/10.5194/bg-19-295-2022, https://doi.org/10.5194/bg-19-295-2022, 2022
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Oxygen minimum zones in the ocean are characterized by enhanced carbon dioxide (CO2) levels and are being further acidified by increasing anthropogenic atmospheric CO2. Here we report CO2 system measurements in a mesocosm study offshore Peru during a rare coastal El Niño event to investigate how CO2 dynamics may respond to ongoing ocean deoxygenation. Our observations show that nitrogen limitation, productivity, and plankton community shift play an important role in driving the CO2 dynamics.
Cited articles
Bian, C., Jiang, W., and Greatbatch, R. J.: An exploratory model study of
sediment transport sources and deposits in the Bohai Sea, Yellow Sea, and
East China Sea, J. Geophys. Res.-Oceans, 118, 5908–5923,
https://doi.org/10.1002/2013JC009116, 2013. a, b, c
Bopp, L., Resplandy, L., Untersee, A., Le Mezo, P., and Kageyama, M.: Ocean
(de)oxygenation from the Last Glacial Maximum to the twenty-first century:
insights from Earth System models, Philos. T. R. Soc. A, 375, 20160323,
https://doi.org/10.1098/rsta.2016.0323, 2017. a, b, c, d
Carton, J. A. and Giese, B. S.: A Reanalysis of Ocean Climate Using Simple
Ocean Data Assimilation (SODA), Mon. Weather Rev., 136, 2999–3017,
https://doi.org/10.1175/2007MWR1978.1, 2008. a
Chen, C.-T. A., Hsing, L.-Y., Liu, C.-L., and Wang, S.-L.: Degree of nutrient
consumption of upwelled water in the Taiwan Strait based on dissolved organic
phosphorus or nitrogen, Mar. Chem., 87, 73–86,
https://doi.org/10.1016/j.marchem.2004.01.006, 2004. a
Chi, L., Song, X., Yuan, Y., Wang, W., Zhou, P., Fan, X., Cao, X., and Yu, Z.:
Distribution and key influential factors of dissolved oxygen off the
Changjiang River Estuary (CRE) and its adjacent waters in China, Mar.
Pollut. Bull., 125, 440–450, https://doi.org/10.1016/j.marpolbul.2017.09.063, 2017. a, b
Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi,
S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P.,
Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C.,
Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B.,
Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler,
M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J.,
Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N.,
and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of
the data assimilation system, Q. J. Roy. Meteor. Soc., 137, 553–597,
https://doi.org/10.1002/qj.828, 2011. a
Egbert, G. D. and Erofeeva, S. Y.: Efficient Inverse Modeling of Barotropic
Ocean Tides, J. Atmos. Ocean. Tech., 19, 183–204,
https://doi.org/10.1175/1520-0426(2002)019<0183:EIMOBO>2.0.CO;2, 2002. a
Fan, W. and Song, J.: A numerical study of the seasonal variations of
nutrients in the Changjiang River estuary and its adjacent sea area, Ecol.
Model., 291, 69–81, https://doi.org/10.1016/j.ecolmodel.2014.07.026, 2014. a, b
Feng, Y., Fennel, K., Jackson, G. A., DiMarco, S. F., and Hetland, R. D.: A
model study of the response of hypoxia to upwelling-favorable wind on the
northern Gulf of Mexico shelf, J. Marine Syst., 131, 63–73,
https://doi.org/10.1016/j.jmarsys.2013.11.009, 2014. a
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
Fennel, K., Wilkin, J., Levin, J., Moisan, J., O'Reilly, J., and Haidvogel, D.:
Nitrogen cycling in the Middle Atlantic Bight: Results from a
three-dimensional model and implications for the North Atlantic nitrogen
budget, Global Biogeochem. Cy., 20, 1–14, https://doi.org/10.1029/2005GB002456, 2006. a, b, c, d, e
Fennel, K., Hetland, R., Feng, Y., and DiMarco, S.: A coupled physical-biological model of the Northern Gulf of Mexico shelf: model description, validation and analysis of phytoplankton variability, Biogeosciences, 8, 1881–1899, https://doi.org/10.5194/bg-8-1881-2011, 2011. a, b
Fennel, K., Hu, J., Laurent, A., Marta-Almeida, M., and Hetland, R.:
Sensitivity of hypoxia predictions for the northern Gulf of Mexico to
sediment oxygen consumption and model nesting, J. Geophys. Res.-Oceans, 118,
990–1002, https://doi.org/10.1002/jgrc.20077, 2013. a, b
Gao, L., Li, D., Ishizaka, J., Zhang, Y., Zong, H., and Guo, L.: Nutrient
dynamics across the river-sea interface in the Changjiang (Yangtze River)
estuary–East China Sea region, Limnol. Oceanogr., 60, 2207–2221,
https://doi.org/10.1002/lno.10196, 2015. a
Garcia, H. E., Boyer, T. P., Locarnini, R. A., Antonov, J. I., Mishonov, A. V.,
Baranova, O. K., Zweng, M. M., Reagan, J. R., Johnson, D. R., and Levitus,
S.: World Ocean Atlas 2013. Volume 3: Dissolved oxygen, apparent oxygen
utilization, and oxygen saturation, Tech. rep., National Oceanic and
Atmospheric Administration (NOAA), Silver Spring, MD, https://doi.org/10.7289/V5XG9P2W,
2013a. a
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Baranova, O. K.,
Zweng, M. M., Reagan, J. R., Johnson, D. R., Mishonov, A. V., and Levitus,
S.: World Ocean Atlas 2013. Volume 4: Dissolved inorganic nutrients
(phosphate, nitrate, silicate), Tech. rep., National Oceanic and Atmospheric
Administration (NOAA), Silver Spring, MD, https://doi.org/10.7289/V5J67DWD, 2013b. a
Große, F.:
Regional Ocean Modeling System (ROMS), version 3.7, with added capability to produce output for the ETRAC software,
available at: https://github.com/FabianGrosse/ROMS_3.7_for_ETRAC,
(last access: 20 August 2019), 2018a. a
Große, F.:
Element TRACing software for numerical models (ETRAC), available at: https://github.com/FabianGrosse/ETRAC (last access: 20 August 2019), 2018b. a
Große, F., Kreus, M., Lenhart, H.-J., Pätsch, J., and Pohlmann, T.:
A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on
the Oxygen Dynamics of the North Sea, Front. Mar. Sci., 4, 383,
https://doi.org/10.3389/fmars.2017.00383, 2017. a, b, c
Große, F., Fennel, K., and Laurent, A.: Quantifying the Relative
Importance of Riverine and Open-Ocean Nitrogen Sources for Hypoxia Formation
in the Northern Gulf of Mexico, J. Geophys. Res.-Oceans, 124, 5451–5467,
https://doi.org/10.1029/2019JC015230, 2019. a, b, c, d
Guo, X., Miyazawa, Y., and Yamagata, T.: The Kuroshio onshore intrusion along
the shelf break of the East China Sea: The origin of the Tsushima Warm
Current, J. Phys. Oceanogr., 36, 2205–2231, https://doi.org/10.1175/JPO2976.1, 2006. a, b, c
Haidvogel, D. B., Arango, H., Budgell, W. P., Cornuelle, B. D., Curchitser, E.,
Di Lorenzo, E., Fennel, K., Geyer, W. R., Hermann, A. J., Lanerolle, L.,
Levin, J., McWilliams, J. C., Miller, A. J., Moore, A. M., Powell, T. M.,
Shchepetkin, A. F., Sherwood, C. R., Signell, R. P., Warner, J. C., and
Wilkin, J.: Ocean forecasting in terrain-following coordinates: Formulation
and skill assessment of the Regional Ocean Modeling System, J. Comput.
Phys., 227, 3595–3624, https://doi.org/10.1016/j.jcp.2007.06.016, 2008. a, b
Hetland, R. D. and Zhang, X.: Interannual Variation in Stratification over the
Texas–Louisiana Continental Shelf and Effects on Seasonal Hypoxia, in:
Modeling Coastal Hypoxia, edited by: Dubravko, J., Rose, K. A., Hetland,
R. D., and Fennel, K., 49–60, Springer, Cham, Switzerland,
https://doi.org/10.1007/978-3-319-54571-4_3, 2017. a
Laurent, A., Fennel, K., Hu, J., and Hetland, R.: Simulating the effects of phosphorus limitation in the Mississippi and Atchafalaya River plumes, Biogeosciences, 9, 4707–4723, https://doi.org/10.5194/bg-9-4707-2012, 2012. a
Laurent, A., Fennel, K., Cai, W.-J., Huang, W.-J., Barbero, L., and Wanninkhof,
R.: Eutrophication-induced acidification of coastal waters in the northern
Gulf of Mexico: Insights into origin and processes from a coupled
physical-biogeochemical model, Geophys. Res. Lett., 44, 946–956,
https://doi.org/10.1002/2016GL071881, 2017. a
Laurent, A., Fennel, K., Ko, D. S., and Lehrter, J.: Climate Change Projected
to Exacerbate Impacts of Coastal Eutrophication in the Northern Gulf of
Mexico, J. Geophys. Res.-Oceans, 123, 3408–3426, https://doi.org/10.1002/2017JC013583,
2018. a
Li, X., Bianchi, T., Yang, Z., Osterman, L. E., Allison, M. E., DiMarco,
S. F., and Yang, H.: Historical trends of hypoxia in Changjiang River
estuary: Applications of chemical biomarkers and microfossils, J. Marine
Syst., 86, 57–68, https://doi.org/10.1016/j.jmarsys.2011.02.003, 2011. a
Liu, S. M., Zhang, J., Chen, H. T., Wu, Y., Xiong, H., and Zhang, Z. F.:
Nutrients in the Changjiang and its tributaries, Biogeochemistry, 62,
1–18, https://doi.org/10.1023/A:1021162214304, 2003. a
Liu, S. M., Hong, G.-H., Zhang, J., Ye, X. W., and Jiang, X. L.: Nutrient budgets for large Chinese estuaries, Biogeosciences, 6, 2245–2263, https://doi.org/10.5194/bg-6-2245-2009, 2009. a
Liu, S. M., Qi, X. H., Li, X., Ye, H. R., Wu, Y., Ren, J. L., Zhang, J., and
Xu, W. Y.: Nutrient dynamics from the Changjiang (Yangtze River) estuary to
the East China Sea, J. Marine Syst., 154, 15–27,
https://doi.org/10.1016/j.jmarsys.2015.05.010, 2016. a
Locarnini, R. A., Mishonov, A. V., Antonov, J. I., Boyer, T. P., Garcia, H. E.,
Baranova, O. K., Zweng, M. M., Paver, C. R., Reagan, J. R., Johnson, D. R.,
Hamilton, M., Seidov, D., and Levitus, S.: World Ocean Atlas 2013. Volume 1:
Temperature, Tech. rep., National Oceanic and Atmospheric Administration
(NOAA), Silver Spring, MD, https://doi.org/10.7289/V55X26VD, 2013. a
McDougall, T. J. and Barker, P. M.: Getting started with TEOS-10 and the Gibbs
Seawater (GSW) oceanographic toolbox, Tech. rep., SCOR/IAPSO, available at:
http://www.teos-10.org/pubs/gsw/v3_04/pdf/Getting_Started.pdf (last access: 20 August 2019),
2011. a
Ménesguen, A., Cugier, P., and Leblond, I.: A new numerical technique
for tracking chemical species in a multi-source, coastal ecosystem, applied
to nitrogen causing Ulva blooms in the Bay of Brest (France), Limnol.
Oceanogr., 51, 591–601, https://doi.org/10.4319/lo.2006.51.1_part_2.0591, 2006. a, b
Qian, W., Dai, M., Xu, M., Kao, S.-J., 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. a
Rabalais, N. N., Turner, R. E., and Wiseman Jr., W. J.: Gulf of Mexico
Hypoxia, A.K.A. “The Dead Zone”, Annu. Rev. Ecol. Syst., 33, 235–263,
https://doi.org/10.1146/annurev.ecolsys.33.010802.150513, 2002. a
Radtke, H., Neumann, T., Voss, M., and Fennel, W.: Modeling pathways of
riverine nitrogen and phosphorus in the Baltic Sea, J. Geophys.
Res.-Oceans, 117, 1–15, https://doi.org/10.1029/2012JC008119, 2012. a
Rutherford, K. and Fennel, K.: Diagnosing transit times on the northwestern North Atlantic continental shelf, Ocean Sci., 14, 1207–1221, https://doi.org/10.5194/os-14-1207-2018, 2018. a
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic oxygen
content during the past five decades, Nature, 542, 335,
https://doi.org/10.1038/nature21399, 2017. a
Seitzinger, S. P., Harrison, J. A., Dumont, E., Beusen, A. H. W., and Bouwman,
A. F.: Sources and delivery of carbon, nitrogen, and phosphorus to the
coastal zone: An overview of Global Nutrient Export from Watersheds (NEWS)
models and their application, Global Biogeochem. Cy., 19, GB4S01,
https://doi.org/10.1029/2005GB002606, 2005. a
Shi, W., Wang, M., and Jiang, L.: Spring-neap tidal effects on satellite ocean
color observations in the Bohai Sea, Yellow Sea, and East China Sea, J.
Geophys. Res.-Oceans, 116, 1–13, https://doi.org/10.1029/2011JC007234, 2011. a
Simpson, J. H.: The shelf-sea fronts: implications of their existence and
behaviour, Philos. T. R. Soc. A, 302, 531–546,
https://doi.org/10.1098/rsta.1981.0181, 1981. a
Siswanto, E., Nakata, H., Matsuoka, Y., Tanaka, K., Kiyomoto, Y., Okamura, K.,
Zhu, J., and Ishizaka, J.: The long-term freshening and nutrient increases
in summer surface water in the northern East China Sea in relation to
Changjiang discharge variation, J. Geophys. Res.-Oceans, 113, C10030,
https://doi.org/10.1029/2008JC004812, 2008. a
Song, G., Liu, S., Zhu, Z., Zhai, W., Zhu, C., and Zhang, J.: Sediment oxygen
consumption and benthic organic carbon mineralization on the continental
shelves of the East China Sea and the Yellow Sea, Deep-Sea Res. Pt. II, 124,
53–63, https://doi.org/10.1016/j.dsr2.2015.04.012, 2016. a, b
Thyng, K. M., Greene, C. A., Hetland, R. D., Zimmerle, H. M., and DiMarco,
S. F.: True Colors of Oceanography: Guidelines for Effective and Accurate
Colormap Selection, Oceanography, 29, 9–13, https://doi.org/10.5670/oceanog.2016.66, 2016. a
Tong, Y., Zhao, Y., Zhen, G., Chi, J., Liu, X., Lu, Y., Wang, X., Yao, R.,
Chen, J., and Zhang, W.: Nutrient loads flowing into coastal waters from the
main rivers of China (2006–2012), Sci. Rep.-UK, 5, 16678,
https://doi.org/10.1038/srep16678, 2015. a
Wang, B.: Hydromorphological mechanisms leading to hypoxia off the Changjiang
estuary, Mar. Environ. Res., 67, 53–58,
https://doi.org/10.1016/j.marenvres.2008.11.001, 2009. a
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. a
Wang, H., Yang, Z., Wang, Y., Saito, Y., and Liu, J. P.: Reconstruction of
sediment flux from the Changjiang (Yangtze River) to the sea since the
1860s, J. Hydrol., 349, 318–332, https://doi.org/10.1016/j.jhydrol.2007.11.005, 2008. a
Wang, J., Yan, W., Chen, N., Li, X., and Liu, L.: Modeled long-term changes of
DIN : DIP ratio in the Changjiang River in relation to Chl-α and DO
concentrations in adjacent estuary, Estuar. Coast. Shelf S., 166, 153–160,
https://doi.org/10.1016/j.ecss.2014.11.028, 2015. a
Wang, W., Yu, Z., Song, X., Yuan, Y., Wu, Z., Zhou, P., and Cao, X.: Intrusion
Pattern of the Offshore Kuroshio Branch Current and Its Effects on Nutrient
Contributions in the East China Sea, J. Geophys. Res.-Oceans, 123,
2116–2128, https://doi.org/10.1002/2017JC013538, 2018. a, b
Wu, G., Cao, W., Wang, F., Su, X., Yan, Y., and Guan, Q.: Riverine nutrient
fluxes and environmental effects on China's estuaries, Sci. Total Environ.,
661, 130–137, https://doi.org/10.1016/j.scitotenv.2019.01.120, 2019. a
Yan, W., Zhang, S., Sun, P., and Seitzinger, S. P.: How do nitrogen inputs to
the Changjiang basin impact the Changjiang River nitrate: A temporal analysis
for 1968–1997, Global Biogeochem. Cy., 17, 1091,
https://doi.org/10.1029/2002GB002029, 2003. a, b
Yang, D., Yin, B., Liu, Z., and Feng, X.: Numerical study of the ocean
circulation on the East China Sea shelf and a Kuroshio bottom branch
northeast of Taiwan in summer, J. Geophys. Res.-Oceans, 116, 1–20,
https://doi.org/10.1029/2010JC006777, 2011. a
Yang, D., Yin, B., Liu, Z., Bai, T., Qi, J., and Chen, H.: Numerical study on
the pattern and origins of Kuroshio branches in the bottom water of southern
East China Sea in summer, J. Geophys. Res.-Oceans, 117, 1–16,
https://doi.org/10.1029/2011JC007528, 2012. a, b
Yu, L., Fennel, K., Laurent, A., Murrell, M. C., and Lehrter, J. C.: Numerical analysis of the primary processes controlling oxygen dynamics on the Louisiana shelf, Biogeosciences, 12, 2063–2076, https://doi.org/10.5194/bg-12-2063-2015, 2015. a, b
Zhang, H., Zhao, L., Sun, Y., Wang, J., and Wei, H.: Contribution of sediment
oxygen demand to hypoxia development off the Changjiang Estuary, Estuar.
Coast. Shelf S., 192, 149–157, https://doi.org/10.1016/j.ecss.2017.05.006, 2017. a, b, c
Zhang, J.: Nutrient elements in large Chinese estuaries, Cont. Shelf Res.,
16, 1023–1045, https://doi.org/10.1016/0278-4343(95)00055-0, 1996. a
Zhang, J., Guo, X., and Zhao, L.: Tracing external sources of nutrients in the
East China Sea and evaluating their contributions to primary production,
Prog. Oceanogr., 176, 102122, https://doi.org/10.1016/j.pocean.2019.102122,
2019. a, b, c, d
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. a, b
Zhang, W. G., Wilkin, J. L., and Schofield, O. M. E.: Simulation of Water Age
and Residence Time in New York Bight, J. Phys. Oceanogr., 40, 965–982,
https://doi.org/10.1175/2009JPO4249.1, 2010. a
Zhang, X., Hetland, R. D., Marta-Almeida, M., and DiMarco, S. F.: A
numerical investigation of the Mississippi and Atchafalaya freshwater
transport, filling and flushing times on the Texas-Louisiana Shelf, J.
Geophys. Res.-Oceans, 117, C11009, https://doi.org/10.1029/2012JC008108, 2012. a
Zhao, L. and Guo, X.: Influence of cross-shelf water transport on nutrients and phytoplankton in the East China Sea: a model study, Ocean Sci., 7, 27–43, https://doi.org/10.5194/os-7-27-2011, 2011. a, b
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. a
Zhou, F., Chai, F., Huang, D., Xue, H., Chen, J., Xiu, P., Xuan, J., Li, J.,
Zeng, D., Ni, X., and Wang, K.: Investigation of hypoxia off the Changjiang
Estuary using a coupled model of ROMS-CoSiNE, Prog. Oceanogr., 159,
237–254, https://doi.org/10.1016/j.pocean.2017.10.008, 2017. a, b
Zhou, P., Song, X., Yuan, Y., Wang, W., Cao, X., and Yu, Z.: Intrusion pattern
of the Kuroshio Subsurface Water onto the East China Sea continental shelf
traced by dissolved inorganic iodine species during the spring and autumn of
2014, Mar. Chem., 196, 24–34, https://doi.org/10.1016/j.marchem.2017.07.006, 2017.
a, b, c, d
Zhou, P., Song, X., Yuan, Y., Wang, W., Chi, L., Cao, X., and Yu, Z.:
Intrusion of the Kuroshio Subsurface Water in the southern East China Sea
and its variation in 2014 and 2015 traced by dissolved inorganic iodine
species, Prog. Oceanogr., 165, 287–298, https://doi.org/10.1016/j.pocean.2018.06.011,
2018. a, b, c
Zhu, Z.-Y., Wu, H., Liu, S.-M., Wu, Y., Huang, D.-J., Zhang, J., and Zhang,
G.-S.: 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. a, b, c
Zweng, M. M., Reagan, J. R., Antonov, J. I., Locarnini, R. A., Mishonov, A. V.,
Boyer, T. P., Garcia, H. E., Baranova, O. K., Johnson, D. R., Seidov, D.,
Biddle, M. M., and Levitus, S.: World Ocean Atlas 2013. Volume 2: Salinity,
Tech. rep., National Oceanic and Atmospheric Administration (NOAA), Silver
Spring, MD, https://doi.org/10.7289/V5251G4D, 2013. a
Short summary
In the East China Sea, hypoxia occurs frequently from spring to fall due to high primary production and subsequent decomposition of organic matter. Nitrogen inputs from the Changjiang and the open ocean have been suggested to contribute to hypoxia formation. We used a numerical modelling approach to quantify the relative contributions of these nitrogen sources. We found that the Changjiang dominates, which suggests that nitrogen management in the watershed would improve oxygen conditions.
In the East China Sea, hypoxia occurs frequently from spring to fall due to high primary...
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