Callianassa trilobata (Crustacea: Thalassinidea) influences abundance of meiofauna and biomass, composition, and physiologic state of microbial communities within its burrow

Abstract

Biochemical and traditional methods were used to determine the influence of Caflianassa trilobata on microbiological and meiofaunal communities within its large, hghly consolidated burrow. Sediment was collected from the lining of the shrimp's burrow, the burrow matrix, and ambient, subsurface sediment. The lining and matrix were composed of poorly sorted, fine-grained material compared to sandy ambient sediment. Meiofauna, predominantly nematodes, were most abundant in ambient sediment, not in the burrow as has been found for other species of macrofauna. Concentrations of chlorophyll a were very high in the lining, consistent with the suggestion that C. trilobata lines its burrow walls with seagrass. Analyses of lipids indicated that relative to the matrix and ambient sediment, the lining abounds with pro-and eukaryotic biomass. Thirty-four phospholipid, ester-linked fatty acids (PLFA) were identified and quantified. Fatty acids were assigned to functional groups of microorganisms to assess spatial variations in the absolute abundance and relative proportions of microbial populations. Dominance of prokaryotes was pronounced in all 3 areas, especially the matrix. The lining was the most aerobic location, but anaerobic microhabitats simultaneously allowed proliferation of sulfate-reducing bacteria, e. g. Desulfobacter. A radial trend was detected in the ratio of bacteria with terminally branched PLFA, typical of Gram-positive organisms, to those with unsaturated PLFA common to Gram-negative bacteria. The ratio increased from lining to matrix to ambient sediment. The ratios of tram to cls isomers of 16:lw7 indicated that prokaryotes in the matrix were starved. Through construction and maintenance of its burrow, C. trilobata determines not only the absolute and relative abundances of microbes in its sedimentary environment, but their physiologic state as well.

Community structure and bioturbation potential of macrofauna at four North Sea stations with contrasting food supply

“…One individual of Amphiura filiformis can oxidize a surface of 35 cm2 to a depth of 3 cm in the sediment by extending its arms through the sediment to th.e sediment-water interface and by regular flushing of the feeding void with oxygen-rich water (Ockelmann & Muus 1978). The subsurfacedeposit feeding Callianassa subterranea is known for its extraordinary strong bioturbation capacity (Branch & Pringle 1987, Witbaard & Duineveld 1989) and ability to oxygenate the sediment (Koike & Mukai 1983, Dobbs & Guckert 1988, Forster & Graf 1995. The branched burrow systems of C. subterranea are continuously rebuilt and reach down to 80 cm into the sediment (Nickel & Atlunson 1995), resulting in sediment turnover rates of up to 12 kg m-2 d-'.…”

The Function of Marine Critical Transition Zones and the Importance of Sediment Biodiversity

“…When it is present, the burrowing, respiratory, and feeding activities of this species reduce sulfide and contaminant levels and promote the establishment of a diverse infaunal community (Stull and others 1986). Interactions between burrower diversity and decomposition functions may be complex, as burrowers produce geochemical gradients and microenvironments in sediments that diversify the microbial assemblage (Dobbs and Guckert 1988).…”

Relative importance of macrofaunal burrows for the microbial mineralization of pyrene in marine sediments: impact of macrofaunal species and organic matter quality

“…Macrofaunal burrows in both aquatic and terrestrial systems appear to harbor distinct microbial communities, often greater in terms of biomass, diversity or activity, as compared to non-burrow soil and sediment (Dobbs & Guckert 1988, Tiunov & Scheu 1999, Bird et al 2000. Microbial communities collected in marine macrofaunal burrows have also been reported to be highly species-specific (Steward et al 1996).…”