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Tracing 13C-enriched dissolved and particulate organic carbon in the bacteria-containing coral reef sponge Halisarca caerulea: evidence for DOM feeding

Goeij de, J.M. and Moodley, L. and Houtekamer, M.J. and Carballeira, N.M. and Duyl van, F.C. (2008) Tracing 13C-enriched dissolved and particulate organic carbon in the bacteria-containing coral reef sponge Halisarca caerulea: evidence for DOM feeding. Limnology and Oceanography, 53, 1376-1386. ISSN 0024-3590.

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Official URL: http://dx.doi.org/10.4319/lo.2008.53.4.1376

Abstract

Here we report on the trophodynamics of the bacteria-containing coral reef sponge Halisarca caerulea. The assimilation and respiration of the 13C-enriched substrates glucose, algal-derived dissolved and particulate organic matter (diatom-DOM and -POM), and bacteria were followed in 1- and 6-h incubations. Except for glucose, all substrates were readily processed by the sponge, with assimilation being the major fate. 13C-Enrichment patterns in fatty acid biomarkers revealed that sponge dissolved organic 13C assimilation was both direct and bacteria mediated as tracer carbon was recovered both in bacteria-specific and nonbacterial fatty acid. This is the first direct evidence of DOM incorporation by sponges. The present study demonstrates that the encrusting sponge H. caerulea feeds on both DOM and POM and given their dominant coverage of the largest coral reef habitat (coral cavities) it is proposed that organic matter assimilation by cryptic reef sponges may represent an important, largely overlooked ecological function. Quantitatively significant DOM processing may not be the exclusive function of the microbial world on coral reefs; sponges transform DOM to biomass, and thus retain and store organic matter in the reef system.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:4904
Deposited On:30 Sep 2009 02:00
Last Modified:15 Jan 2014 09:18

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