Drivers of organic carbon stocks in eutrophic lake sediments after reestablishment of submerged aquatic vegetation

Organic C stocks in lacustrine sediments can be an important C sink. We therefore addressed the drivers of the sediment organic carbon (SOC) and labile organic carbon (LOC) concentrations after submerged aquatic vegetation (SAV) reestablishment by sowing in a eutrophic lake.

We conducted a field experiment in Lake Datong, a eutrophic lake in the Dongting Lake basin. There are two distinct areas in the lake: the DX area, where the reestablished SAV persisted for three years; the MN area, where SAV persisted for 1.5 years. Our investigation focused on assessing SOC and LOC concentrations within the 0–20 cm sediment layers, and examining their correlations with sediment physicochemical properties and potential enzyme activities.

SOC and LOC concentrations were higher in the DX than MN area. Sediment total nitrogen (TN) concentrations, porosity, and potential BG and NAG enzyme activities were higher in the DX than MN area. While dry bulk density (DBD) and sediment pH were lower in the DX than MN area. Those sediment physicochemical properties and potential enzyme activities in different reestablished areas explained variations in SOC and LOC concentrations to varying extents.

Our findings indicate that SAV reestablishment time holds great potential for accumulating SOC and LOC concentrations by altering the stability of SOC and enhancing sediment nutrient levels.