Articles | Volume 15, issue 20
https://doi.org/10.5194/bg-15-6105-2018
© Author(s) 2018. 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-15-6105-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Oct 2018
Research article |
| 18 Oct 2018
| 18 Oct 2018
Impacts of anthropogenic inputs on hypoxia and oxygen dynamics in the Pearl River estuary
Bin Wang
School of Environmental Science and Engineering, Sun Yat-Sen
University, Guangzhou, 510275, China
Department of Oceanography, Dalhousie University, Halifax, Nova
Scotia, Canada
Jiatang Hu
CORRESPONDING AUTHOR
School of Environmental Science and Engineering, Sun Yat-Sen
University, Guangzhou, 510275, China
Guangdong Provincial Key Laboratory of Environmental Pollution
Control and Remediation Technology, Guangzhou 510275, China
Shiyu Li
CORRESPONDING AUTHOR
School of Environmental Science and Engineering, Sun Yat-Sen
University, Guangzhou, 510275, China
Guangdong Provincial Key Laboratory of Environmental Pollution
Control and Remediation Technology, Guangzhou 510275, China
Liuqian Yu
Department of Oceanography, Dalhousie University, Halifax, Nova
Scotia, Canada
Jia Huang
School of Environmental Science and Engineering, Sun Yat-Sen
University, Guangzhou, 510275, China
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In this work, we measured the chemistry of seawater from samples obtained from different depths and locations off the east coast of the Northeast Greenland National Park to determine what is influencing concentrations of dissolved CO2. Historically, the region has always been thought to take up CO2 from the atmosphere, but we show that it is possible for the region to become a source in late summer. We discuss the variables that may be related to such changes.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
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Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences, 21, 3617–3639, https://doi.org/10.5194/bg-21-3617-2024, https://doi.org/10.5194/bg-21-3617-2024, 2024
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The European Arctic is experiencing rapid regional warming, causing glaciers that terminate in the sea to retreat onto land. Due to this process, the area of a well-studied fjord, Hornsund, has increased by around 100 km2 (40%) since 1976. Combining satellite and in situ data with a mathematical model, we estimated that, despite some negative consequences of glacial meltwater release, such emerging coastal waters could mitigate climate change by increasing carbon uptake and storage by sediments.
Mallory C. Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan R. Carter, and Matthew D. Eisaman
Biogeosciences, 21, 3551–3570, https://doi.org/10.5194/bg-21-3551-2024, https://doi.org/10.5194/bg-21-3551-2024, 2024
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Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Results show that CO2 equilibration occurred on the order of weeks to months, was consistent with values expected from equilibration calculations, and was limited by mineral precipitation at high pH and CaCO3 saturation.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
Biogeosciences, 21, 3425–3440, https://doi.org/10.5194/bg-21-3425-2024, https://doi.org/10.5194/bg-21-3425-2024, 2024
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Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. Dissolved NO was supersaturated in the Elbe Estuary, indicating that it is a source of atmospheric NO. The observed distribution of dissolved NO most likely resulted from nitrification.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
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Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Deep S. Banerjee and Jozef Skakala
EGUsphere, https://doi.org/10.22541/essoar.171405637.76928549/v1, https://doi.org/10.22541/essoar.171405637.76928549/v1, 2024
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Nitrate is a crucial nutrient in oceans. Excess nutrients can trigger uncontrolled algae growth (eutrophication), damaging marine ecosystems. We used a machine learning tool to generate a skilled, gap-free, bi-decadal surface nitrate dataset from sparse observations. This dataset reveals areas on the North West European Shelf at risk of eutrophication, bi-decadal trends in coastal nitrate, and an impact of winter nitrate on spring phytoplankton blooms.
Amanda Y. L. Cheong, Kogila Vani Annammala, Ee Ling Yong, Yongli Zhou, Robert S. Nichols, and Patrick Martin
Biogeosciences, 21, 2955–2971, https://doi.org/10.5194/bg-21-2955-2024, https://doi.org/10.5194/bg-21-2955-2024, 2024
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We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
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In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
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Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
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Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
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This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
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Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
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Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
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Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
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We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
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The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
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The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
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Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
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The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
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Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
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Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
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The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
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Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
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We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Cited articles
Chung, J., Gary, C., and Heinke, W.: Pearl River Estuary Pollution Project
(PREPP), Cont. Shelf Res., 24, 1739–1744, 2004.
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.
Du, J. and Shen, J.: Decoupling the influence of biological and physical
processes on the dissolved oxygen in the Chesapeake Bay, J. Geophys. Res.-Ocean., 120, 78–93, https://doi.org/10.1002/2014JC010422, 2015.
Fontugne, M. R. and Jouanneau, J.-M.: Modulation of the particulate organic
carbon flux to the ocean by a macrotidal estuary: Evidence from measurements
of carbon isotopes in organic matter from the Gironde system, Estuar. Coast.
Shelf Sci., 24, 377–387, https://doi.org/10.1016/0272-7714(87)90057-6, 1987.
Forrest, D. R., Hetland, R. D., and Dimarco, S. F.: Multivariable statistical
regression models of the areal extent of hypoxia over the Texas-Louisiana
continental shelf, Environ. Res. Lett., 6, 1–10,
https://doi.org/10.1088/1748-9326/6/4/045002, 2011.
Grantham, B. A., Chan, F., Nielsen, K. J., Fox, D. S., Barth, J. A., Huyer,
A., Lubchenco, J., and Menge, B. A.: Upwelling-driven nearshore hypoxia
signals ecosystem and oceanographic changes in the northeast Pacific,
Nature, 429, 749–754, https://doi.org/10.1038/nature02605, 2004.
Green, R. E., Bianchi, T. S., Dagg, M. J., Walker, N. D., and Breed, G. A.:
An organic carbon budget for the Mississippi River turbidity plume and plume
contributions to air-sea CO2 fluxes and bottom water hypoxia, Estuar.
Coast., 29, 579–597, https://doi.org/10.1007/BF02784284, 2006.
Guo, W., Ye, F., Xu, S., and Jia, G.: Seasonal variation in sources and
processing of particulate organic carbon in the Pearl River estuary, South
China, Estuar. Coast. Shelf Sci., 167, 540–548,
https://doi.org/10.1016/j.ecss.2015.11.004, 2015.
Hagy, J. D., Boynton, W. R., Keefe, C. W., and Wood, K. V.: Hypoxia in
Chesapeake Bay, 1950–2001: Long-term change in relation to nutrient loading
and river flow, Estuaries, 27, 634–658, https://doi.org/10.1007/BF02907650, 2004.
He, B., Dai, M., Zhai, W., Guo, X., and Wang, L.: Hypoxia in the upper
reaches of the Pearl River Estuary and its maintenance mechanisms: A
synthesis based on multiple year observations during 2000–2008, Mar. Chem., 167, 13–24,
https://doi.org/10.1016/j.marchem.2014.07.003, 2014.
Hong, B. and Shen, J.: Linking dynamics of transport timescale and
variations of hypoxia in the Chesapeake Bay, J. Geophys. Res.-Ocean.,
118, 6017–6029, https://doi.org/10.1002/2013JC008859, 2013.
Hu, J. and Li, S.: Modeling the mass fluxes and transformations of nutrients
in the Pearl River Delta, China, J. Mar. Syst., 78, 146–167,
https://doi.org/10.1016/j.jmarsys.2009.05.001, 2009.
Hu, J., Peng, P., Jia, G., Mai, B., and Zhang, G.: Distribution and sources
of organic carbon, nitrogen and their isotopes in sediments of the
subtropical Pearl River estuary and adjacent shelf, Southern China, Mar.
Chem., 98, 274–285, https://doi.org/10.1016/j.marchem.2005.03.008, 2006.
Hu, J., Li, S., and Geng, B.: Modeling the mass flux budgets of water and
suspended sediments for the river network and estuary in the Pearl River
Delta, China, J. Mar. Syst., 88, 252–266,
https://doi.org/10.1016/j.jmarsys.2011.05.002, 2011.
HydroQual, Inc.: A Primer for ECOMSED Version 1.3, HydroQual, Inc., Mahwah,
NJ, 2002.
HydroQual, Inc.: User's Guide for RCA (Release 3.0), HydroQual, Inc.,
Mahwah, NJ, 2004.
Jia, G.-D. and Peng, P.-A.: Temporal and spatial variations in signatures of
sedimented organic matter in Lingding Bay (Pearl estuary), southern China,
Mar. Chem., 82, 47–54, https://doi.org/10.1016/S0304-4203(03)00050-1, 2003.
Justić, D., Rabalais, N. N., and Turner, R. E.: Simulated responses of
the Gulf of Mexico hypoxia to variations in climate and anthropogenic
nutrient loading, J. Mar. Syst., 42, 115–126,
https://doi.org/10.1016/S0924-7963(03)00070-8, 2003.
Laurent, A., Fennel, K., Ko, D., and Lehrter, J.: Climate Change Projected to
Exacerbate Impacts of Coastal Eutrophication in the Northern Gulf of Mexico,
J. Geophys. Res.-Ocean., 123, 3408–3426, https://doi.org/10.1002/2017JC013583, 2018.
Li, X., Bianchi, T. S., Yang, Z., Osterman, L. E., Allison, M. A., DiMarco,
S. F., and Yang, G.: Historical trends of hypoxia in Changjiang River
estuary: Applications of chemical biomarkers and microfossils, J. Mar.
Syst., 86, 57–68, https://doi.org/10.1016/j.jmarsys.2011.02.003, 2011.
Lin, H. Y., Liu, S., and Han, W. Y.: Potential Trigger CTB, from Seasonal
Bottom Water Hypoxia in the Pearl River Estuary, J. Zhanjiang Ocean Univ.,
21, 25–29, 2001.
Liu, D., Hu, J., Li, S., and Huang, J.: Validation and application of a
three-dimensional coupled water quality and sediment model of the Pearl
River Estuary, Huanjing Kexue Xuebao/Acta Sci. Circumstantiae, 36,
4025–4036, https://doi.org/10.13671/j.hjkxxb.2016.0145, 2016.
Luo, L., Li, S. Y., and Wang, D. X.: Modelling of hypoxia in the Pearl River
estuary in summer, Adv. Water Sci., 19, 729–735, 2008.
Mellor, G. L. and Yamada, T.: Development of a turbulence closure model for
geophysical fluid problems, Rev. Geophys., 20, 851–875,
https://doi.org/10.1029/RG020i004p00851, 1982.
Middelburg, J. J. and Herman, P. M. J.: Organic matter processing in tidal
estuaries, Mar. Chem., 106, 127–147,
https://doi.org/10.1016/J.MARCHEM.2006.02.007, 2007.
Montes, I., Dewitte, B., Gutknecht, E., Paulmier, A., Dadou, I., Oschlies,
A., and Garçon, V.: High-resolution modeling of the Eastern Tropical
Pacific oxygen minimum zone: Sensitivity to the tropical oceanic
circulation, J. Geophys. Res.-Ocean., 119, 5515–5532,
https://doi.org/10.1002/2014JC009858, 2014.
Murrell, M. C. and Lehrter, J. C.: Sediment and Lower Water Column Oxygen
Consumption in the Seasonally Hypoxic Region of the Louisiana Continental
Shelf, Estuar. Coast., 34, 912–924, https://doi.org/10.1007/s12237-010-9351-9,
2011.
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.
Ou, S., Zhang, H., and Wang, D. X.: Dynamics of the buoyant plume off the
Pearl River Estuary in summer, Environ. Fluid Mech., 9, 471–492,
https://doi.org/10.1007/s10652-009-9146-3, 2009.
Quigg, A., Sylvan, J. B., Gustafson, A. B., Fisher, T. R., Oliver, R. L.,
Tozzi, S., and Ammerman, J. W.: Going West: Nutrient Limitation of Primary
Production in the Northern Gulf of Mexico and the Importance of the
Atchafalaya River, Aquat. Geochemistry, 17, 519–544,
https://doi.org/10.1007/s10498-011-9134-3, 2011.
Rabalais, N. N., Díaz, R. J., Levin, L. A., Turner, R. E., Gilbert, D., and Zhang, J.:
Dynamics and distribution of natural and human-caused hypoxia, Biogeosciences, 7, 585–619, https://doi.org/10.5194/bg-7-585-2010, 2010.
Rabouille, C., Conley, D. J., Dai, M. H., Cai, W. J., Chen, C. T. A.,
Lansard, B., Green, R., Yin, K., Harrison, P. J., Dagg, M., and McKee, B.:
Comparison of hypoxia among four river-dominated ocean margins: The
Changjiang (Yangtze), Mississippi, Pearl, and Rhône rivers, Cont. Shelf
Res., 28, 1527–1537, https://doi.org/10.1016/j.csr.2008.01.020, 2008.
Scavia, D., Kelly, E. L. A., and Hagy, J. D.: A simple model for forecasting
the effects of nitrogen loads on Chesapeake Bay hypoxia, Estuar.
Coast., 29, 674–684, https://doi.org/10.1007/BF02784292, 2006.
Smagorinsky, J.: General circulation experiments with the primitive equations: I. The basic equations, Mon. Weather Rev., 91, 99–164, 1963.
Strokal, M., Kroeze, C., Li, L., Luan, S., Wang, H., Yang, S., and Zhang, Y.:
Increasing dissolved nitrogen and phosphorus export by the Pearl River
(Zhujiang): a modeling approach at the sub-basin scale to assess effective
nutrient management, Biogeochemistry, 125, 221–242,
https://doi.org/10.1007/s10533-015-0124-1, 2015.
Su, J., Dai, M., He, B., Wang, L., Gan, J., Guo, X., Zhao, H., and Yu, F.:
Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in
a large eutrophic estuary: the lower reach of the Pearl River Estuary,
China, Biogeosciences, 14, 4085–4099, https://doi.org/10.5194/bg-14-4085-2017, 2017.
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.
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., Hu, J., Li, S., and Liu, D.: A numerical analysis of biogeochemical
controls with physical modulation on hypoxia during summer in the Pearl
River estuary, Biogeosciences, 14, 2979–2999, https://doi.org/10.5194/bg-14-2979-2017, 2017.
Wang, X.-C., Chen, R. F., and Gardner, G. B.: Sources and transport of
dissolved and particulate organic carbon in the Mississippi River estuary
and adjacent coastal waters of the northern Gulf of Mexico, Mar. Chem.,
89, 241–256, 2004.
Ye, F., Guo, W., Shi, Z., Jia, G., and Wei, G.: Seasonal dynamics of
particulate organic matter and its response to flooding in the Pearl River
Estuary, China, revealed by stable isotope (δ13C and δ15N) analyses, J. Geophys. Res.-Ocean., 122, 1–22,
https://doi.org/10.1002/2017JC012931, 2017.
Ye, H., Chen, C., Sun, Z., Tang, S., Song, X., Yang, C., Tian, L., and Liu,
F.: Estimation of the Primary Productivity in Pearl River Estuary Using
MODIS Data, Estuar. Coast., 38, 506–518,
https://doi.org/10.1007/s12237-014-9830-5, 2014.
Yin, K., Lin, Z., and Ke, Z.: Temporal and spatial distribution of dissolved
oxygen in the Pearl River Estuary and adjacent coastal waters, Cont. Shelf
Res., 24, 1935–1948, https://doi.org/10.1016/j.csr.2004.06.017, 2004.
Yu, F., Zong, Y., Lloyd, J. M., Huang, G., Leng, M. J., Kendrick, C., Lamb,
A. L., and Yim, W. W. S.: Bulk organic δ13C and C/N as indicators for
sediment sources in the Pearl River delta and estuary, southern China,
Estuar. Coast. Shelf Sci., 87, 618–630, https://doi.org/10.1016/j.ecss.2010.02.018,
2010.
Yu, L., Fennel, K., and Laurent, A.: A modeling study of physical controls on
hypoxia generation in the northern Gulf of Mexico, J. Geophys. Res.-Ocean., 120, 5019–5039, https://doi.org/10.1002/2014JC010634, 2015a.
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, 2015b.
Zhang, H. and Li, S.: Effects of physical and biochemical processes on the
dissolved oxygen budget for the Pearl River Estuary during summer, J. Mar.
Syst., 79, 65–88, https://doi.org/10.1016/j.jmarsys.2009.07.002, 2010.
Zhang, L., Qin, X., Yang, H., Huang, Q., and Liu, P.: Transported Fluxes of
the Riverine Carbon and Seasonal Variation in Pearl River Basin, Environ.
Sci., 34, 3025–3034, https://doi.org/10.13227/j.hjkx.2013.08.043, 2013.
Short summary
A physical–biogeochemical model was applied to study the response of hypoxia and oxygen dynamics to different riverine inputs. Results showed that the hypoxia in the Pearl River estuary was most sensitive to riverine inputs of POC, followed by DO and nutrients. This study also highlighted the significance of re-aeration for its buffering effects; i.e. the re-aeration responded rapidly to the perturbations of riverine inputs and in turn moderated the DO changes impacted by these perturbations.
A physical–biogeochemical model was applied to study the response of hypoxia and oxygen...
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