Trophic Ecology of the Tropical Pacific Sponge Mycale grandis Inferred from Amino Acid Compound-Specific Isotopic Analyses.

Trophic Ecology of the Tropical Pacific Sponge Mycale grandis Inferred from Amino Acid Compound-Specific Isotopic Analyses. Microb Ecol. 2019 Jul 17;: Authors: Shih JL, Selph KE, Wall CB, Wallsgrove NJ, Lesser MP, Popp BN Abstract Many sponges host abundant and active microbial communities that may play a role in the uptake of dissolved organic matter (DOM) by the sponge holobiont, although the mechanism of DOM uptake and metabolism is uncertain. Bulk and compound-specific isotopic analysis of whole sponge, isolated sponge cells, and isolated symbiotic microbial cells of the shallow water tropical Pacific sponge Mycale grandis were used to elucidate the trophic relationships between the host sponge and its associated microbial community. δ15N and δ13C values of amino acids in M. grandis isolated sponge cells are not different from those of its bacterial symbionts. Consequently, there is no difference in trophic position of the sponge and its symbiotic microbes indicating that M. grandis sponge cell isolates do not display amino acid isotopic characteristics typical of metazoan feeding. Furthermore, both the isolated microbial and sponge cell fractions were characterized by a similarly high ΣV value-a measure of bacterial-re-synthesis of organic matter calculated from the sum of variance among individual δ15N values of trophic amino acids. These high ΣV values observed in the sponge suggest that M. grandis is not reliant on trans...
Source: Microbial Ecology - Category: Microbiology Authors: Tags: Microb Ecol Source Type: research