We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Role of Particle Resuspension in Maintaining Hypoxic Level in the Pearl River Estuary.
- Authors
Cui, Yongsheng; Wu, Jiaxue; Tan, Ehui; Kao, Shuh‐Ji
- Abstract
Eutrophication‐induced seasonal hypoxia in the coastal ocean has widely been attributed to the excessive oxygen consumption induced by settling and deposition of organic particles on sea floor. However, the role of particle resuspension in maintaining the hypoxic level has seldom been investigated based on field observations. Here, we carefully examined particle resuspension and its contribution to oxygen consumption in the Pearl River Estuary in July 2020. The bottom hypoxia was found to appear over the organic‐rich mudbelt off the estuary. Concentrated particles in suspension near the bottom, which were induced by particle resuspension rather than by particle settling, occurred near the front created by shelf salinity intrusions where bottom hypoxia appeared in the summer. The total dissolved oxygen (DO) depletion responsible for bottom hypoxia can be exclusively estimated from the DO budget during the tidal cycle. The water DO depletion dominated by particle resuspension is larger than or at least comparable to sediment oxygen demand. This highlights that the DO budget in the absence of particle resuspension overestimates the DO level in coastal hypoxia. Overall, our results suggest that particle resuspension play a vital role in maintaining the DO level of bottom hypoxia. This finding will be helpful to understand the impact of particle resuspension on coastal hypoxia, as well as other marine environmental problems in estuary and coastal ocean. Plain Language Summary: Coastal hypoxia has become an environmental and ecological hazard over the world. However, its extent and degree is still challenging because the oxygen processes and budget have not yet been straightforward to quantify in complex estuary and coastal waters. Field observations in the Pearl River Estuary in the 2020 summer showed that the core of seasonal hypoxia existed at the front created by shelf salinity intrusion. We further evaluated the contribution of particle resuspension to oxygen consumption based on the dissolved oxygen budget. It was found that particle resuspension can effectively promote water oxygen consumption, and enhance the degree of coastal hypoxia. This finding will be helpful to understand the impact of particle resuspension on coastal hypoxia, as well as other marine environmental problems in estuary and coastal ocean. Key Points: Particle resuspension occurs near the front created by shelf salinity intrusion where bottom hypoxia appears in the summerOxygen consumption induced by particle resuspension is at least comparable to sediment oxygen demand in generating bottom hypoxiaThe dissolved oxygen (DO) budget in the absence of particle resuspension overestimates the DO level in coastal hypoxia
- Subjects
HYPOXIA (Water); TERRITORIAL waters; ESTUARIES; OCEAN bottom; OXYGEN consumption; OXYGEN in water
- Publication
Journal of Geophysical Research. Oceans, 2022, Vol 127, Issue 8, p1
- ISSN
2169-9275
- Publication type
Article
- DOI
10.1029/2021JC018166