Carbon Reduction Associated with Sediment Reworking through Burrows of the Thalassinid Mud Shrimp Laomedia sp. (Crustacea: Laomediidae) from Korean Intertidal Sediments

Abstract

This study evaluated the biotic and abiotic factors influencing the sediment reworking rate (SRR) of Laomedia sp. through in situ measurements and assessed the organic carbon reduction by comparing carbon concentrations between particles collected from the water column and reworked sediments. The SRR was significantly correlated with the duration of submergence at high elevation, whereas it showed a stronger correlation with mound height than with the duration of submergence at low elevation. The organic carbon content of suspended particles was reduced by 68% by the sediment reworking of Laomedia sp., with a mean organic carbon reduction of 0.01 gC ind.−1 d−1. This reduction resulted from particle selection by the inhabitant and by accumulation along the burrow walls. The estimated annual organic carbon reduction associated with the sediment reworking was 12.8 gC m−2 yr−1. The transport of organic carbon from the burrows into the water column was comparatively high relative to other species. These findings suggest that Laomedia sp. plays a significant role in enhancing the carbon cycle as an important bioturbator, with its burrows acting as carbon sinks by trapping organic carbon in intertidal sediments. Therefore, bioturbation by macroinvertebrates should be considered when evaluating carbon sequestration in intertidal sediments.