Articles | Volume 19, issue 14
https://doi.org/10.5194/bg-19-3469-2022
© Author(s) 2022. 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-19-3469-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
27 Jul 2022
Research article |
| 27 Jul 2022
| 27 Jul 2022
Interannual variabilities, long-term trends, and regulating factors of low-oxygen conditions in the coastal waters off Hong Kong
Zheng Chen
School of Environmental Science and Engineering, Sun Yat-sen
University, Guangzhou, 510275, China
Department of Oceanography, Dalhousie University, Halifax, Nova
Scotia, B3H 4R2, Canada
Chuang Xu
Center for Water Resources and Environment, Sun Yat-sen University,
Guangzhou, 510275, China
Zhongren Zhang
School of Environmental Science and Engineering, Sun Yat-sen
University, Guangzhou, 510275, China
Guangdong Zhihuan Innovative Environmental Technology Co., Ltd.,
Guangzhou, 510030, China
Shiyu Li
School of Environmental Science and Engineering, Sun Yat-sen
University, Guangzhou, 510275, China
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
Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai),
Zhuhai, 519000, China
Related authors
No articles found.
Jiatang Hu, Zhongren Zhang, Bin Wang, and Jia Huang
Biogeosciences, 18, 5247–5264, https://doi.org/10.5194/bg-18-5247-2021, https://doi.org/10.5194/bg-18-5247-2021, 2021
Short summary
Short summary
In situ observations over 42 years were used to explore the long-term changes to low-oxygen conditions in the Pearl River estuary. Apparent expansion of the low-oxygen conditions in summer was identified, primarily due to the combined effects of increased anthropogenic inputs and decreased sediment load. Large areas of severe low-oxygen events were also observed in early autumn and were formed by distinct mechanisms. The estuary seems to be growing into a seasonal, estuary-wide hypoxic zone.
Bin Wang, Katja Fennel, and Liuqian Yu
Ocean Sci., 17, 1141–1156, https://doi.org/10.5194/os-17-1141-2021, https://doi.org/10.5194/os-17-1141-2021, 2021
Short summary
Short summary
We demonstrate that even sparse BGC-Argo profiles can substantially improve biogeochemical prediction via a priori model tuning. By assimilating satellite surface chlorophyll and physical observations, subsurface distributions of physical properties and nutrients were improved immediately. The improvement of subsurface chlorophyll was modest initially but was greatly enhanced after adjusting the parameterization for light attenuation through further a priori tuning.
Bin Wang, Katja Fennel, Liuqian Yu, and Christopher Gordon
Biogeosciences, 17, 4059–4074, https://doi.org/10.5194/bg-17-4059-2020, https://doi.org/10.5194/bg-17-4059-2020, 2020
Short summary
Short summary
We assess trade-offs between different types of biological observations, specifically satellite ocean color and BGC-Argo profiles and the benefits of combining both for optimizing a biogeochemical model of the Gulf of Mexico. Using all available observations leads to significant improvements in observed and unobserved variables (including primary production and C export). Our results highlight the significant benefits of BGC-Argo measurements for biogeochemical model optimization and validation.
Bin Wang, Jiatang Hu, Shiyu Li, Liuqian Yu, and Jia Huang
Biogeosciences, 15, 6105–6125, https://doi.org/10.5194/bg-15-6105-2018, https://doi.org/10.5194/bg-15-6105-2018, 2018
Short summary
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.
Bin Wang, Jiatang Hu, Shiyu Li, and Dehong Liu
Biogeosciences, 14, 2979–2999, https://doi.org/10.5194/bg-14-2979-2017, https://doi.org/10.5194/bg-14-2979-2017, 2017
Short summary
Short summary
We proposed a novel method named the physical modulation method to quantify the contributions of boundary conditions, the source and sink processes occurring in local and adjacent waters to DO conditions. A mass balance analysis of DO based on the physical modulation method indicated that the DO conditions were mainly controlled by source and sink processes, among which the sediment oxygen demand and re-aeration were two main processes controlling the spatial extent and the duration of hypoxia.
Related subject area
Biogeochemistry: Coastal Ocean
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
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
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
Observed and projected 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
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
Observed and projected global warming pressure on coastal hypoxia
Benthic alkalinity fluxes from coastal sediments of the Baltic and North seas: comparing approaches and identifying knowledge gaps
Investigating the effect of nickel concentration on phytoplankton growth to assess potential side-effects of ocean alkalinity enhancement
Unprecedented summer hypoxia in southern Cape Cod Bay: an ecological response to regional climate change?
Causes of the extensive hypoxia in the Gulf of Riga in 2018
Trawling effects on biogeochemical processes are mediated by fauna in high-energy biogenic-reef-inhabited coastal sediments
Drought recorded by Ba∕Ca in coastal benthic foraminifera
A nitrate budget of the Bohai Sea based on an isotope mass balance model
Suspended particulate matter drives the spatial segregation of nitrogen turnover along the hyper-turbid Ems estuary
Marine CO2 system variability along the northeast Pacific Inside Passage determined from an Alaskan ferry
Reviews and syntheses: Spatial and temporal patterns in seagrass metabolic fluxes
Mixed layer depth dominates over upwelling in regulating the seasonality of ecosystem functioning in the Peruvian upwelling system
Temporal dynamics of surface ocean carbonate chemistry in response to natural and simulated upwelling events during the 2017 coastal El Niño near Callao, Peru
Pelagic primary production in the coastal Mediterranean Sea: variability, trends, and contribution to basin-scale budgets
Contrasting patterns of carbon cycling and dissolved organic matter processing in two phytoplankton–bacteria communities
Biophysical controls on seasonal changes in the structure, growth, and grazing of the size-fractionated phytoplankton community in the northern South China Sea
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton
Modeling cyanobacteria life cycle dynamics and historical nitrogen fixation in the Baltic Proper
Simultaneous assessment of oxygen- and nitrate-based net community production in a temperate shelf sea from a single ocean glider
Reviews and syntheses: Physical and biogeochemical processes associated with upwelling in the Indian Ocean
Particulate organic carbon dynamics in the Gulf of Lion shelf (NW Mediterranean) using a coupled hydrodynamic–biogeochemical model
Technical note: Novel triple O2 sensor aquatic eddy covariance instrument with improved time shift correction reveals central role of microphytobenthos for carbon cycling in coral reef sands
Long-term spatiotemporal variations in and expansion of low-oxygen conditions in the Pearl River estuary: a study synthesizing observations during 1976–2017
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula
Temporal variability and driving factors of the carbonate system in the Aransas Ship Channel, TX, USA: a time series study
Nitrogen loss processes in response to upwelling in a Peruvian coastal setting dominated by denitrification – a mesocosm approach
Retracing hypoxia in Eckernförde Bight (Baltic Sea)
The impact of the freeze–melt cycle of land-fast ice on the distribution of dissolved organic matter in the Laptev and East Siberian seas (Siberian Arctic)
The fate of upwelled nitrate off Peru shaped by submesoscale filaments and fronts
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.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
EGUsphere, https://doi.org/10.5194/egusphere-2023-705, https://doi.org/10.5194/egusphere-2023-705, 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 here show that foraminiferal burrow formation increase the oxygen penetration depth in the sediment. Leading to a change in the structure of the prokaryotic community.
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.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-223, https://doi.org/10.5194/bg-2022-223, 2022
Revised manuscript accepted for BG
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.
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
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
Short summary
Short summary
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
Short summary
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
Short summary
Short summary
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.
Paula Maria Salgado-Hernanz, Aurore Regaudie-de-Gioux, David Antoine, and Gotzon Basterretxea
Biogeosciences, 19, 47–69, https://doi.org/10.5194/bg-19-47-2022, https://doi.org/10.5194/bg-19-47-2022, 2022
Short summary
Short summary
For the first time, this study presents the characteristics of primary production in coastal regions of the Mediterranean Sea based on satellite-borne observations for the period 2002–2016. The study concludes that there are significant spatial and temporal variations among different regions. Quantifying primary production is of special importance in the marine food web and in the sequestration of carbon dioxide from the atmosphere to the deep waters.
Samu Elovaara, Eeva Eronen-Rasimus, Eero Asmala, Tobias Tamelander, and Hermanni Kaartokallio
Biogeosciences, 18, 6589–6616, https://doi.org/10.5194/bg-18-6589-2021, https://doi.org/10.5194/bg-18-6589-2021, 2021
Short summary
Short summary
Dissolved organic matter (DOM) is a significant carbon pool in the marine environment. The composition of the DOM pool, as well as its interaction with microbes, is complex, yet understanding it is important for understanding global carbon cycling. This study shows that two phytoplankton species have different effects on the composition of the DOM pool and, through the DOM they produce, on the ensuing microbial community. These communities in turn have different effects on DOM composition.
Yuan Dong, Qian P. Li, Zhengchao Wu, Yiping Shuai, Zijia Liu, Zaiming Ge, Weiwen Zhou, and Yinchao Chen
Biogeosciences, 18, 6423–6434, https://doi.org/10.5194/bg-18-6423-2021, https://doi.org/10.5194/bg-18-6423-2021, 2021
Short summary
Short summary
Temporal change of plankton growth and grazing are less known in the coastal ocean, not to mention the relevant controlling mechanisms. Here, we performed monthly size-specific dilution experiments outside a eutrophic estuary over a 1-year cycle. Phytoplankton growth was correlated to nutrients and grazing mortality to total chlorophyll a. A selective grazing on small cells may be important for maintaining high abundance of large-chain-forming diatoms in this eutrophic system.
Kiefer O. Forsch, Lisa Hahn-Woernle, Robert M. Sherrell, Vincent J. Roccanova, Kaixuan Bu, David Burdige, Maria Vernet, and Katherine A. Barbeau
Biogeosciences, 18, 6349–6375, https://doi.org/10.5194/bg-18-6349-2021, https://doi.org/10.5194/bg-18-6349-2021, 2021
Short summary
Short summary
We show that for an unperturbed cold western Antarctic Peninsula fjord, the seasonality of iron and manganese is linked to the dispersal of metal-rich meltwater sources. Geochemical measurements of trace metals in meltwaters, porewaters, and seawater, collected during two expeditions, showed a seasonal cycle of distinct sources. Finally, model results revealed that the dispersal of surface meltwater and meltwater plumes originating from under the glacier is sensitive to katabatic wind events.
Jenny Hieronymus, Kari Eilola, Malin Olofsson, Inga Hense, H. E. Markus Meier, and Elin Almroth-Rosell
Biogeosciences, 18, 6213–6227, https://doi.org/10.5194/bg-18-6213-2021, https://doi.org/10.5194/bg-18-6213-2021, 2021
Short summary
Short summary
Dense blooms of cyanobacteria occur every summer in the Baltic Proper and can add to eutrophication by their ability to turn nitrogen gas into dissolved inorganic nitrogen. Being able to correctly estimate the size of this nitrogen fixation is important for management purposes. In this work, we find that the life cycle of cyanobacteria plays an important role in capturing the seasonality of the blooms as well as the size of nitrogen fixation in our ocean model.
Tom Hull, Naomi Greenwood, Antony Birchill, Alexander Beaton, Matthew Palmer, and Jan Kaiser
Biogeosciences, 18, 6167–6180, https://doi.org/10.5194/bg-18-6167-2021, https://doi.org/10.5194/bg-18-6167-2021, 2021
Short summary
Short summary
The shallow shelf seas play a large role in the global cycling of CO2 and also support large fisheries. We use an autonomous underwater vehicle in the central North Sea to measure the rates of change in oxygen and nutrients.
Using these data we determine the amount of carbon dioxide taken out of the atmosphere by the sea and measure how productive the region is.
These observations will be useful for improving our predictive models and help us predict and adapt to a changing ocean.
Puthenveettil Narayana Menon Vinayachandran, Yukio Masumoto, Michael J. Roberts, Jenny A. Huggett, Issufo Halo, Abhisek Chatterjee, Prakash Amol, Garuda V. M. Gupta, Arvind Singh, Arnab Mukherjee, Satya Prakash, Lynnath E. Beckley, Eric Jorden Raes, and Raleigh Hood
Biogeosciences, 18, 5967–6029, https://doi.org/10.5194/bg-18-5967-2021, https://doi.org/10.5194/bg-18-5967-2021, 2021
Short summary
Short summary
Upwelling in the coastal ocean triggers biological productivity and thus enhances fisheries. Therefore, understanding the phenomenon of upwelling and the underlying mechanisms is important. In this paper, the present understanding of the upwelling along the coastline of the Indian Ocean from the coast of Africa all the way up to the coast of Australia is reviewed. The review provides a synthesis of the physical processes associated with upwelling and its impact on the marine ecosystem.
Gaël Many, Caroline Ulses, Claude Estournel, and Patrick Marsaleix
Biogeosciences, 18, 5513–5538, https://doi.org/10.5194/bg-18-5513-2021, https://doi.org/10.5194/bg-18-5513-2021, 2021
Short summary
Short summary
The Gulf of Lion shelf is one of the most productive areas in the Mediterranean. A model is used to study the mechanisms that drive the particulate organic carbon (POC). The model reproduces the annual cycle of primary production well. The shelf appears as an autotrophic ecosystem with a high production and as a source of POC for the adjacent basin. The increase in temperature induced by climate change could impact the trophic status of the shelf.
Alireza Merikhi, Peter Berg, and Markus Huettel
Biogeosciences, 18, 5381–5395, https://doi.org/10.5194/bg-18-5381-2021, https://doi.org/10.5194/bg-18-5381-2021, 2021
Short summary
Short summary
The aquatic eddy covariance technique is a powerful method for measurements of solute fluxes across the sediment–water interface. Data measured by conventional eddy covariance instruments require a time shift correction that can result in substantial flux errors. We introduce a triple O2 sensor eddy covariance instrument that by design eliminates these errors. Deployments next to a conventional instrument in the Florida Keys demonstrate the improvements achieved through the new design.
Jiatang Hu, Zhongren Zhang, Bin Wang, and Jia Huang
Biogeosciences, 18, 5247–5264, https://doi.org/10.5194/bg-18-5247-2021, https://doi.org/10.5194/bg-18-5247-2021, 2021
Short summary
Short summary
In situ observations over 42 years were used to explore the long-term changes to low-oxygen conditions in the Pearl River estuary. Apparent expansion of the low-oxygen conditions in summer was identified, primarily due to the combined effects of increased anthropogenic inputs and decreased sediment load. Large areas of severe low-oxygen events were also observed in early autumn and were formed by distinct mechanisms. The estuary seems to be growing into a seasonal, estuary-wide hypoxic zone.
Indah Ardiningsih, Kyyas Seyitmuhammedov, Sylvia G. Sander, Claudine H. Stirling, Gert-Jan Reichart, Kevin R. Arrigo, Loes J. A. Gerringa, and Rob Middag
Biogeosciences, 18, 4587–4601, https://doi.org/10.5194/bg-18-4587-2021, https://doi.org/10.5194/bg-18-4587-2021, 2021
Short summary
Short summary
Organic Fe speciation is investigated along a natural gradient of the western Antarctic Peninsula from an ice-covered shelf to the open ocean. The two major fronts in the region affect the distribution of ligands. The excess ligands not bound to dissolved Fe (DFe) comprised up to 80 % of the total ligand concentrations, implying the potential to solubilize additional Fe input. The ligands on the shelf can increase the DFe residence time and fuel local primary production upon ice melt.
Melissa R. McCutcheon, Hongming Yao, Cory J. Staryk, and Xinping Hu
Biogeosciences, 18, 4571–4586, https://doi.org/10.5194/bg-18-4571-2021, https://doi.org/10.5194/bg-18-4571-2021, 2021
Short summary
Short summary
We used 5+ years of discrete samples and 10 months of hourly sensor measurements to explore temporal variability and environmental controls on pH and pCO2 at the Aransas Ship Channel. Seasonal and diel variability were both present but small compared to other regions in the literature. Despite the small tidal range, tidal control often surpassed biological control. In comparison with sensor data, discrete samples were generally representative of mean annual and seasonal carbonate chemistry.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
Short summary
Short summary
Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Heiner Dietze and Ulrike Löptien
Biogeosciences, 18, 4243–4264, https://doi.org/10.5194/bg-18-4243-2021, https://doi.org/10.5194/bg-18-4243-2021, 2021
Short summary
Short summary
In recent years fish-kill events caused by oxygen deficit have been reported in Eckernförde Bight (Baltic Sea). This study sets out to understand the processes causing respective oxygen deficits by combining high-resolution coupled ocean circulation biogeochemical modeling, monitoring data, and artificial intelligence.
Jens A. Hölemann, Bennet Juhls, Dorothea Bauch, Markus Janout, Boris P. Koch, and Birgit Heim
Biogeosciences, 18, 3637–3655, https://doi.org/10.5194/bg-18-3637-2021, https://doi.org/10.5194/bg-18-3637-2021, 2021
Short summary
Short summary
The Arctic Ocean receives large amounts of river water rich in terrestrial dissolved organic matter (tDOM), which is an important component of the Arctic carbon cycle. Our analysis shows that mixing of three major freshwater sources is the main factor that regulates the distribution of tDOM concentrations in the Siberian shelf seas. In this context, the formation and melting of the land-fast ice in the Laptev Sea and the peak spring discharge of the Lena River are of particular importance.
Jaard Hauschildt, Soeren Thomsen, Vincent Echevin, Andreas Oschlies, Yonss Saranga José, Gerd Krahmann, Laura A. Bristow, and Gaute Lavik
Biogeosciences, 18, 3605–3629, https://doi.org/10.5194/bg-18-3605-2021, https://doi.org/10.5194/bg-18-3605-2021, 2021
Short summary
Short summary
In this paper we quantify the subduction of upwelled nitrate due to physical processes on the order of several kilometers in the coastal upwelling off Peru and its effect on primary production. We also compare the prepresentation of these processes in a high-resolution simulation (~2.5 km) with a more coarsely resolved simulation (~12 km). To do this, we combine high-resolution shipboard observations of physical and biogeochemical parameters with a complex biogeochemical model configuration.
Cited articles
Bordovskiy, O. K.: Sources of organic matter in marine basins, Mar.
Geol., 3, 5–31, https://doi.org/10.1016/0025-3227(65)90003-4,
1965.
Breitburg, D., Levin, L., Oschlies, A., Grégoire, M., Chavez, F.,
Conley, D., Garcon, V., Gilbert, D., Gutiérrez, D., Isensee, K.,
Jacinto, G., Limburg, K., Montes, I., Naqvi, S. W. A., Pitcher, G.,
Rabalais, N., Roman, M., Rose, K., Seibel, B., and Zhang, J.: Declining
oxygen in the global ocean and coastal waters, Science,
359, 1–13, https://doi.org/10.1126/science.aam7240, 2018.
Jolliffe, I. T. and Cadima, J.: Principal component analysis: a review and recent developments, Philos. T. R. Soc. Math. Phys. Eng. Sci., 374, 20150202, https://doi.org/10.1098/rsta.2015.0202, 2016.
Chen, J., Wang, Z., Tam, C.-Y., Lau, N.-C., Lau, D.-S. D., and Mok, H.-Y.:
Impacts of climate change on tropical cyclones and induced storm surges in
the Pearl River Delta region using pseudo-global-warming method, Scientific
Reports, 10, 1965, https://doi.org/10.1038/s41598-020-58824-8, 2020.
Chen, Z.: The long-term monthly discharge data of hydrological stations in the Pearl River during 1994–2018, Zenodo [data set], https://doi.org/10.5281/zenodo.6859871, 2022.
Chi, L., Song, X., Yuan, Y., Wang, W., Cao, X., Wu, Z., and Yu, Z.: Main
factors dominating the development, formation and dissipation of hypoxia off
the Changjiang Estuary (CE) and its adjacent waters, China, Environ.
Pollut., 265, 115066, https://doi.org/10.1016/j.envpol.2020.115066, 2020.
Conley, D., Carstensen, J., Aigars, J., Axe, P., Bonsdorff, E., Eremina, T.,
Haahti, B.-M., Humborg, C., Jonsson, P., Kotta, J., Lännegren, C.,
Larsson, U., Maximov, A., Medina, M., Lysiak-Pastuszak, E.,
Remeikaitė-Nikienė, N., Walve, J., Wilhelms, S., and Zillén, L.:
Hypoxia is increasing in the coastal zone of the Baltic Sea, Environ.
Sci. Technol., 45, 6777–6783, https://doi.org/10.1021/es201212r, 2011.
Cui, Y., Wu, J. X., Ren, J., and Xu, J.: Physical dynamics structures and
oxygen budget of summer hypoxia in the Pearl River Estuary: Dynamical
structures and oxygen budget of hypoxia, Limnol. Oceanogr., 64,
131–148, https://doi.org/10.1002/lno.11025, 2018.
Dai, M., Zhai, W., Cai, W.-J., Callahan, J., Huang, B., Shang, S., Huang,
T., Li, X., Lu, Z., Chen, W., and Chen, Z.: Effects of an estuarine
plume-associated bloom on the carbonate system in the lower reaches of the
Pearl River estuary and the coastal zone of the northern South China Sea,
Cont. Shelf Res., 28, 1416–1423, https://doi.org/10.1016/j.csr.2007.04.018, 2008.
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.
Feng, Y., DiMarco, S. F., and Jackson, G. A.: Relative role of wind forcing
and riverine nutrient input on the extent of hypoxia in the northern Gulf of
Mexico, Geophys. Res. Lett., 39, L09601, https://doi.org/10.1029/2012GL051192, 2012.
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.
Fennel, K. and Testa, J.: Biogeochemical Controls on Coastal Hypoxia, Annu. Rev. Mar. Sci., 11, 105–130, https://doi.org/10.1146/annurev-marine-010318-095138, 2018.
Forrest, D., Hetland, R., and Dimarco, S.: Multivariable statistical
regression models of the areal extent of hypoxia over the Texas-Louisiana
Shelf, Environ. Res. Lett., 6, 045002,
https://doi.org/10.1088/1748-9326/6/4/045002, 2011.
Gao, N., Ma, Y., Zhao, M., Zhang, L., Zhan, H., and He, Q.: Quantile
Analysis of Long-Term Trends of Near-Surface Chlorophyll-a in the Pearl
River Plume, Water, 12, 1662, https://doi.org/10.3390/w12061662, 2020.
Hu, J., Zhang, Z., Wang, B., and Huang, J.: Long-term spatiotemporal variations in and expansion of low-oxygen conditions in the Pearl River estuary: a study synthesizing observations during 1976–2017, Biogeosciences, 18, 5247–5264, https://doi.org/10.5194/bg-18-5247-2021, 2021.
Justić, D., Rabalais, N., and Turner, R.: Simulated Responses of the
Gulf of Mexico Hypoxia to Variations in Climate and Anthropogenic Nutrient
Loading, J. Marine Syst., 42, 115–126,
https://doi.org/10.1016/S0924-7963(03)00070-8, 2003.
Laurent, A. and Fennel, K.: Time-evolving, spatially explicit forecasts of
the Northern Gulf of Mexico hypoxic zone, Environ. Sci.
Technol., 53, 14449–14458, https://doi.org/10.1021/acs.est.9b05790, 2019.
Li, D., Gan, J., Hui, C., Yu, L., Liu, Z., Lu, Z., Kao, S.-J., and Dai, M.:
Spatiotemporal development and dissipation of hypoxia induced by variable
wind-driven shelf circulation off the Pearl River Estuary: Observational and
modeling studies, J. Geophys. Res.-Oceans, 126,
e2020JC016700, https://doi.org/10.1029/2020JC016700, 2021.
Li, G., Liu, J., Diao, Z., Jiang, X., Li, J., Ke, Z., Shen, P., Ren, L.,
Huang, L., and Tan, Y.: Subsurface low dissolved oxygen occurred at fresh-
and saline-water intersection of the Pearl River estuary during the summer
period, Mar. Pollut. Bull., 126, 585–591, https://doi.org/10.1016/j.marpolbul.2017.09.061, 2018.
Li, M., Lee, Y. J., Testa, J. M., Li, Y., Ni, W., Kemp, W. M., and Di Toro,
D. M.: What drives interannual variability of hypoxia in Chesapeake Bay:
Climate forcing versus nutrient loading?, Geophys. Res. Lett., 43,
2127–2134, https://doi.org/10.1002/2015GL067334, 2016.
Li, X., Lu, C., Zhang, Y., Zhao, H., Wang, J., Liu, H., and Yin, K.: Low
dissolved oxygen in the Pearl River estuary in summer: Long-term
spatio-temporal patterns, trends, and regulating factors, Mar. Pollut. Bull., 151, 110814, https://doi.org/10.1016/j.marpolbul.2019.110814, 2020.
Ludsin, S. A., Zhang, X., Brandt, S. B., Roman, M. R., Boicourt, W. C.,
Mason, D. M., and Costantini, M.: Hypoxia-avoidance by planktivorous fish in
Chesapeake Bay: Implications for food web interactions and fish recruitment,
J. Exp. Mar. Biol. Ecol., 381, S121–S131,
https://doi.org/10.1016/j.jembe.2009.07.016, 2009.
Luo, L., Li, S., and Wang, D.: Hypoxia in the Pearl River Estuary, the South
China Sea, in July 1999, Aquat. Ecosyst. Health, 12,
418–428, https://doi.org/10.1080/14634980903352407, 2009.
Lu, Z., Gan, J., Dai, M., Liu, H., and Zhao, X.: Joint effects of extrinsic
biophysical fluxes and intrinsic hydrodynamics on the formation of hypoxia
west off the Pearl River Estuary, J. Geophys. Res.-Oceans,
123, 6241–6259, 2018.
Meier, H. E. M., Eilola, K., Almroth-Rosell, E., Schimanke, S., Kniebusch,
M., Höglund, A., Pemberton, P., Liu, Y., Väli, G., and Saraiva, S.:
Disentangling the impact of nutrient load and climate changes on Baltic Sea
hypoxia and eutrophication since 1850, Clim. Dynam., 53, 1145–1166,
https://doi.org/10.1007/s00382-018-4296-y, 2019.
Meyers, P. A. and Ishiwatari, R.: Lacustrine organic geochemistry – an
overview of indicators of organic matter sources and diagenesis in lake
sediments, Org. Geochem., 20, 867–900, https://doi.org/10.1016/0146-6380(93)90100-P, 1993.
Murphy, R., Kemp, W., and Ball, W.: Long-Term Trends in Chesapeake Bay
Seasonal Hypoxia, Stratification, and Nutrient Loading, Estuar.
Coast., 34, 1293–1309, https://doi.org/10.1007/s12237-011-9413-7, 2011.
Ni, W., Li, M., Ross, A. C., and Najjar, R. G.: Large Projected Decline in
Dissolved Oxygen in a Eutrophic Estuary Due to Climate Change, J. Geophys. Res.-Oceans, 124, 8271–8289, https://doi.org/10.1029/2019JC015274, 2019.
Ni, W., Li, M., and Testa, J. M.: Discerning effects of warming, sea level
rise and nutrient management on long-term hypoxia trends in Chesapeake Bay,
Sci. Total Environ., 737, 139717, https://doi.org/10.1016/j.scitotenv.2020.139717, 2020.
Obenour, D., Scavia, D., Rabalais, N., Turner, R., and Michalak, A.:
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.
Qian, W., Gan, J., Liu, J., He, B., Lu, Z., Guo, X., Wang, D., Guo, L.,
Huang, T., and Dai, M.: Current status of emerging hypoxia in a eutrophic
estuary: The lower reach of the Pearl River Estuary, China, Estuar. Coast. Shelf S., 205, 58–67, https://doi.org/10.1016/j.ecss.2018.03.004, 2018.
Rabalais, N., Turner, R., and Boesch, D.: A brief summary of hypoxia on the
northern Gulf of Mexico continental shelf: 1985–1988, Geo. Soc. S. P., 58, 35–47, https://doi.org/10.1144/GSL.SP.1991.058.01.03,
1991.
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.
Raymond, P. and Bauer, J.: Use of 14C and 13C natural abundances for
evaluating riverine, estuarine, and coastal DOC and POC sources and cycling:
A review and synthesis, Org. Geochem., 32, 469–485,
https://doi.org/10.1016/S0146-6380(00)00190-X, 2001.
Shi, Z., Liu, K., Zhang, S., Xu, H., and Liu, H.: Spatial distributions of
mesozooplankton biomass, community composition and grazing impact in
association with hypoxia in the Pearl River Estuary, Estuar. Coast.
Shelf Sci., 225, 106237, https://doi.org/10.1016/j.ecss.2019.05.019, 2019.
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.
Sun, J., Lin, B., Li, K., and Jiang, G.: A modelling study of residence time
and exposure time in the Pearl River Estuary, China, J.
Hydro-Environ. Res., 8, 281–291, https://doi.org/10.1016/j.jher.2013.06.003, 2014.
Testa, J., Murphy, R., Brady, D., and Kemp, W.: Nutrient- and
Climate-Induced Shifts in the Phenology of Linked Biogeochemical Cycles in a
Temperate Estuary, Front. Mar. Sci., 5, 114,
https://doi.org/10.3389/fmars.2018.00114, 2018.
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, B., Hu, J., Li, S., Yu, L., and Huang, J.: Impacts of anthropogenic inputs on hypoxia and oxygen dynamics in the Pearl River estuary, Biogeosciences, 15, 6105–6125, https://doi.org/10.5194/bg-15-6105-2018, 2018.
Wang, K., Cai, W.-J., Chen, J., Kirchman, D., Wang, B., Fan, W., and Huang,
D.: Climate and Human-Driven Variability of Summer Hypoxia on a Large
River-Dominated Shelf as Revealed by a Hypoxia Index, Front. Mar.
Sci., 8, 634184, https://doi.org/10.3389/fmars.2021.634184, 2021.
Wang, P., Wang, H., and Linker, L.: Relative Importance of Nutrient Load and
Wind on Regulating Interannual Summer Hypoxia in the Chesapeake Bay,
Estuaries Coasts, 38, 1048–1061, https://doi.org/10.1007/s12237-014-9867-5, 2015.
Wen, G., Liang, Z., Xu, X., Cao, R., Wan, Q., Ji, G., Lin, W., Wang, J.,
Yang, J., and Huang, T.: Inactivation of fungal spores in water using ozone:
Kinetics, influencing factors and mechanisms, Water Res., 185, 116218,
https://doi.org/10.1016/j.watres.2020.116218, 2020.
Xu, C., Gong, L., Tong, J., Chen, D., and Singh, V.: Analysis of spatial
distribution and temporal trend of reference ET in Changjiang catchments,
J. Hydrol., 327, 81–93, https://doi.org/10.1016/j.jhydrol.2005.11.029, 2006.
Xu, J., Yin, K. D., Liu, H., Lee, J., Anderson, D., Ho, A., and Harrison,
P.: A comparison of eutrophication impacts in two harbours in Hong Kong with
different hydrodynamics, J. Marine Syst., 83, 276–286, https://doi.org/10.1016/j.jmarsys.2010.04.002, 2010.
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, L., Fennel, K., and Laurent, A.: A modeling study of physical controls
on hypoxia generation in the northern Gulf of Mexico, J. Geophys. Res.-Oceans, 120, 5019–5039, https://doi.org/10.1002/2014JC010634, 2015.
Yu, L., Gan, J., Dai, M., Hui, C., Lu, X., and Li, D.: Modeling the role of
riverine organic matter in hypoxia formation within the coastal transition
zone off the Pearl River Estuary, Limnol. Oceanogr., 66, 452–468,
https://doi.org/10.1002/lno.11616, 2021.
Zhang, H. and Li, S.: Effects of physical and biochemical processes on the
dissolved oxygen budget for the Pearl River Estuary during summer, J. Marine Syst., 79, 65–88, https://doi.org/10.1016/j.jmarsys.2009.07.002, 2010.
Zhang, T., Chen, Y., and Paw, U. K. T.: Quantifying the impact of climate variables
on reference evapotranspiration in Pearl River Basin, China, Hydrolog.
Sci. J., 64, 1–13, https://doi.org/10.1080/02626667.2019.1662021, 2019.
Zhang, W., Moriarty, J. M., Wu, H., and Feng, Y.: Response of bottom hypoxia
off the Changjiang River Estuary to multiple factors: A numerical study,
Ocean Model., 159, 101751, https://doi.org/10.1016/j.ocemod.2021.101751, 2021.
Zhang, X., Ren, Y., Yin, J., Lin, Z., and Zheng, D.: Spatial and temporal
variation patterns of reference evapotranspiration across the
Qinghai-Tibetan Plateau during 1971–2004, J. Geophys. Res, 114, D15105, https://doi.org/10.1029/2009JD011753, 2009.
Zhou, Y., Scavia, D., and Michalak, A.: Nutrient loading and meteorological
conditions explain interannual variability of hypoxia in Chesapeake Bay,
Limnol. Oceanogr., 59, 373–384, https://doi.org/10.4319/lo.2014.59.2.0373, 2014.
Zhu, Z., Zhang, J., Wu, Y., Zhang, Y., Lin, J., and Liu, S.: 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.
Short summary
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.
Deterioration of low-oxygen conditions in the coastal waters off Hong Kong was revealed by...
Altmetrics
Final-revised paper
Preprint