关键词: 滤食性双壳贝类养殖, 沉积有机碳, 生物沉积, 再矿化, 长期埋藏, 碳汇判定

Abstract: Filter-feeding bivalve aquaculture enhances the transport of particulate organic carbon (POC) to the seafloor through filtration, selective feeding, and biodeposition, thereby altering the sources, fluxes, and reactivity of sedimentary organic carbon (SOC). However, aquaculture-induced organic carbon inputs are characterized by “high input, high reactivity, and high uncertainty”. After entering the sediment, a fraction is returned to the water column through microbial remineralization, resuspension, and lateral transport, whereas another fraction is stabilized through rapid burial, mineral protection, and microbial reworking, which is ultimately retained through long-term burial. Whether enhanced POC sedimentation results in a net sedimentary carbon sink therefore depends on the partitioning of newly added organic carbon among remineralization, physical export, transient preservation, and long-term burial. The current debate centers on whether increased POC sedimentation or SOC accumulation in surface sediments can demonstrate a contribution of bivalve aquaculture to sedimentary carbon sequestration. Assessments based solely on sedimentation fluxes or SOC increments may overestimate the carbon-sink effect, whereas an exclusive emphasis on remineralization losses may underestimate the contribution of stabilization and long-term burial. Following the process sequence of “input-remineralization-stabilization and burial”, we synthesized the transformation processes and controlling mechanisms of SOC in filter-feeding bivalve aquaculture systems and clarified the conditions under which aquaculture-induced organic carbon inputs could generate a long-term positive increment in SOC burial and thereby constitute a net sedimentary carbon sink. Future studies should strengthen synchronous observations and coupled accounting of these processes across relevant timescales, quantify SOC burial efficiency and its influencing factors among different bivalve species, farming practices, and environmental conditions, and establish a framework for assessing sedimentary carbon sinks in bivalve aquaculture.

Key words: filter-feeding bivalve aquaculture, sedimentary organic carbon, biodeposition, remineralization, long-term burial, carbon-sink assessment