Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change, yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear. In this study, we conducted high-resolution profiling observations of CO2 dynamics and net community production (NCP) in a mussel farm located in the Changjiang (Yangtze) River estuary (CRE) during early autumn. Results indicate that the partial pressure of CO2 (pCO2) in the water column was consistently higher than the atmospheric level, averaging 74.75±2.44 Pa, signaling that the mussel farm acted as a CO2 source. The average air-water CO2 exchange flux (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$F_{\text{CO}_{2}}$</EquationSource> <EquationSource Format="MATHML"><math display="block"> <msub> <mi>F</mi> <mrow> <msub> <mtext>CO</mtext> <mrow> <mn>2</mn> </mrow> </msub> </mrow> </msub> </math></EquationSource> </InlineEquation>) averaged −1.91±1.16 mmol/(m2·h), and NCP in the water column (NCPCOL) averaged −6.66±12.81 mmol/(m2·h), revealing a heterotrophic condition. A significant inverse correlation was found between NCPCOL and sea surface pCO2 with a lag time of approximately 3.31 h, highlighting the influence of biological activity in modulating CO2 dynamics. Physical processes such as freshwater inputs, vertical mixing, and wind patterns, also played a crucial role in shaping pCO2 variations. The study emphasizes the complexity of CO2 dynamics in costal aquaculture areas and the need for long-term, high-resolution monitoring to better understand their contribution to climate change mitigation. The high-resolution profiling system provided novel insights into the dynamics of NCP and CO2 fluxes, showing its potential as an advanced tool for studying aquaculture systems. Future research should focus on expanding the geographic and temporal scope of studies, combining observational and modeling approaches to better predict the responses of aquaculture systems to environmental changes.

High-resolution profiling observation of carbon source dynamics in a mussel farm in the Changjiang River estuary during early autumn

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发表日期：

2025年8月26日

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Dawei Xu,
Di Wu,
Shouye Yang,
Yanping Hu,
Kui Wang

摘要

Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change, yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear. In this study, we conducted high-resolution profiling observations of CO₂ dynamics and net community production (NCP) in a mussel farm located in the Changjiang (Yangtze) River estuary (CRE) during early autumn. Results indicate that the partial pressure of CO₂ (pCO₂) in the water column was consistently higher than the atmospheric level, averaging 74.75±2.44 Pa, signaling that the mussel farm acted as a CO₂ source. The average air-water CO₂ exchange flux ( $F_{\text{CO}_{2}}$ $F_{{CO}_{2}}$ ) averaged −1.91±1.16 mmol/(m²·h), and NCP in the water column (NCP_COL) averaged −6.66±12.81 mmol/(m²·h), revealing a heterotrophic condition. A significant inverse correlation was found between NCP_COL and sea surface pCO₂ with a lag time of approximately 3.31 h, highlighting the influence of biological activity in modulating CO₂ dynamics. Physical processes such as freshwater inputs, vertical mixing, and wind patterns, also played a crucial role in shaping pCO₂ variations. The study emphasizes the complexity of CO₂ dynamics in costal aquaculture areas and the need for long-term, high-resolution monitoring to better understand their contribution to climate change mitigation. The high-resolution profiling system provided novel insights into the dynamics of NCP and CO₂ fluxes, showing its potential as an advanced tool for studying aquaculture systems. Future research should focus on expanding the geographic and temporal scope of studies, combining observational and modeling approaches to better predict the responses of aquaculture systems to environmental changes.