The Sediment Reworking of the Mud Shrimp Laomedia sp. (Crustacea: Laomediidae) with Tidal Conditions in the Intertidal Sediments of Gomso Bay, Korea

Abstract

Although the thalassinidean mud shrimp Laomedia sp. is one of the most abundant species in the upper tidal flats along the west coast of Korea, little is known of its ecological characteristics and bioturbation effects on intertidal sediments. This study estimated the sediment reworking rate (SRR) of Laomedia sp. by quantifying in situ sediments ejected from the burrows via direct entrapment and evaluated the effects of tidal conditions on the SRR. The amount of expelled sediments from individual burrows was significantly related to the duration of submergence, whereas SRR showed an increasing trend as elevation increased. The SRR of Laomedia sp. was estimated to be 40 g ind.−1 d−1 and the annual SRR of this species was 72.2 kg m−2 yr−1 based on the density in the study area, which is very high compared to other thalassinidean shrimp. These findings suggest that Laomedia sp. is an important bioturbator in intertidal sediments, and tidal conditions should be considered when evaluating the SRR of this species.