Journal article
Groundwater‐Derived Carbon Promotes Hypoxia and Acidification in a Large Tropical Estuary
Journal of geophysical research. Biogeosciences, Vol.131(3), pp.1-20
03/2026
Metrics
1 Record Views
Abstract
Submarine groundwater discharge (SGD) derived nutrient inputs have been extensively documented. However, SGD-derived carbon fluxes remain largely unconstrained, representing a critical gap in most coastal carbon budgets. Here, we resolve SGD and dissolved carbon budgets in the Pearl River Estuary (PRE), the largest estuary in Southern China surrounded by the world's largest urban conglomerate. Broadly-defined SGD contributes 89%–96% of the dissolved inorganic carbon (DIC) pool (2–4 times riverine inputs) and 20%–70% of the dissolved organic carbon (DOC) fluxes of the PRE. SGD transports DIC exceeding total alkalinity (TAlk) by 2.7–7 times, potentially driving pH decline and acidification of nearshore waters. Groundwater pCO2 values are 10–36 times higher than estuarine waters. SGD-derived DOC mineralization can decrease estuary water pH by 0.04–0.16 units and increase CO2 by 6.0–90.0 μmol L−1, affecting local coral populations and benthic organisms. SGD also reduces seawater dissolved oxygen (DO) by 12–150 μmol L−1 and fuels the development of hypoxic zones. Overall, SGD regionally intensifies seawater hypoxia and acidification, creating challenging conditions for coral reef survival in an already stressed ecosystem. Our findings demonstrate that SGD should be integrated into carbon budgets and ecological assessments of the land-ocean continuum.
Details
- Title
- Groundwater‐Derived Carbon Promotes Hypoxia and Acidification in a Large Tropical Estuary
- Creators
- Zhenyan Wang - China University of Geosciences (Beijing)Yan Zhang - China University of Geosciences (Beijing)Isaac R. Santos - University of GothenburgClare E. Robinson - Western UniversityXuejing Wang - Tianjin UniversityKai Xiao - Yantai Institute of Coastal Zone ResearchXiaolang Zhang - Florida Atlantic UniversityWei Wang - Southern University of Science and TechnologyZhaoxi Liu - Southern University of Science and TechnologyHailong Li - Southern University of Science and Technology
- Publication Details
- Journal of geophysical research. Biogeosciences, Vol.131(3), pp.1-20
- Publisher
- Wiley-Blackwell Publishing, Inc.
- Grant note
- National Natural Science Foundation of China. Grant Numbers: 42130703, 42377065, 42321004 Guangdong-Hong Kong Joint Laboratory for Soil and Groundwater Pollution Control. Grant Number: 2023B1212120001 Guangdong Provincial Key Laboratory for Soil and Groundwater Pollution Control. Grant Number: 2023B1212120002 High Level of Special Funds. Grant Number: G03050K001
- Identifiers
- 991013370454302368
- Copyright
- © 2026. American Geophysical Union. All Rights Reserved.
- Academic Unit
- National Marine Science Centre; National Centre for Naturopathic Medicine
- Language
- English
- Resource Type
- Journal article