The carbon reduction through huge and complex burrow system of thalassinidean mud shrimp Laomedia nov. sp. (Crustacea: Laomediidae) from Korean intertidal

Abstract

Thalassinidean mud shrimp Laomedia nov. sp. is one of the most abundant species in the upper tidal flats of the west coast of Korea. The genus Laomedia is represented by four species; L. astacina, L. paucispinosa, L. healyi and L. barronensis. The burrows inhabited by Laomedia nov. sp. are huge and structurally complex and their size, structure, and morphology are distinctly different from those reported for other Laomedia species, so this species is presumed to be a new Laomedia species. Laomedia nov. sp. burrows have the structural characteristics of being divided into three parts. The upper part consists of a horizontal gallery and a vertical shaft connected to the surface and the lower parts of several horizontal passages are connected to the main gallery to form the middle part of the burrow. The main gallery is inclined, spirally twisted, and extended downwards, and the direction of the twist is periodically reversed in the middle part. In the lower part, the main gallery is extended almost vertically and connected to a horizontally extended chamber at a certain interval of depth. The sediment-water interface by the burrow of Laomedia nov. sp. was increased by up to 1,511%, which is believed to highest value among marine invertebrates. However, little is known of the ecological characteristics and functions of this unique burrow system. The carbon dynamics in the intertidal sediments are influenced by an array of biotic and abiotic factors among which thalassinidean mud shrimps play an important role. We introduce the carbon reduction through unique burrow system of Laomedia nov. sp. by quantifying carbon inflow and outflow via irrigation and sediment reworking of this species.