Release of dissolved and particulate organic matter by the soft coral Lobophytum and subsequent microbial degradation

TitleRelease of dissolved and particulate organic matter by the soft coral Lobophytum and subsequent microbial degradation
Publication TypeJournal Article
Year of Publication2018
AuthorsNakajima R., Haas AF, Silveira C.B, Kelly E.LA, Smith JE, Sandin S., Kelly LW, Rohwer F, Nakatomi N., Kurihara H.
JournalJournal of Experimental Marine Biology and Ecology
Volume504
Pagination53-60
Date Published2018/07
Type of ArticleArticle
ISBN Number0022-0981
Accession NumberWOS:000432770300007
Keywordsacropora-formosa; bacteria; bacterioplankton; C:N ratio; carbon; Coral mucus; doc; Environmental Sciences & Ecology; Marine & Freshwater Biology; mucus; phase-shifts; phosphate-uptake; photosynthesis; POC; reef ecosystem; skeletal growth; Soft corals; stylophora-pistillata
Abstract

Understanding the release and remineralization of organic matter by benthic macroorganisms provides insight into nutrient cycling and microbial metabolism in coral reef environments. The release rate of particulate (POC) and dissolved organic carbon (DOC) by the soft coral Lobophytum crassum was quantified and subsequent bacterial growth rates determined in response to this resource, and compared with results from those of the common hard coral Acropora intermedia. The results of this study show that the soft coral released more DOC than POC into the surrounding seawater, similar to what was measured for the hard coral species. However, the soft coral-derived organic matter fostered a lower microbial growth rate with a lower growth efficiency compared to DOC and POC of hard corals, likely due to the lower C:N ratio of the organic matter derived from soft corals. These results suggest that soft coral exudates are relatively refractory compared to the mucus of hard corals. Possible phase shifts from hard to soft corals on degraded reefs may represent very different changes in microbial community dynamics and metabolism as compared to the widely studied coral-algal phase shifts.

DOI10.1016/j.jembe.2018.02.008
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