Cavity-dwelling suspension feeders in coral reefs - a new link in reef trophodynamics
1999; Inter-Research; Volume: 188; Linguagem: Inglês
10.3354/meps188105
ISSN1616-1599
Autores Tópico(s)Marine Bivalve and Aquaculture Studies
ResumoMEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 188:105-116 (1999) - doi:10.3354/meps188105 Cavity-dwelling suspension feeders in coral reefs--a new link in reef trophodynamics Claudio Richter*, Mark Wunsch Zentrum für Marine Tropenökologie, Fahrenheitstr. 1, 28359 Bremen, Germany *E-mail: crichter@uni-bremen.de ABSTRACT: The small-scale distributions of chlorophyll a (chl a), pheopigments, oxygen and currents were determined in horizontal sections between coral reef cavities and benthic boundary layer waters (BBL) to estimate rates of grazing and respiration by cryptic cavity-dwelling (coelobite) suspension feeders. We investigated 0.5 to 5 m long and 0.1 to 1 m wide cavities in fringing reefs on the western coast of the Gulf of Aqaba (Red Sea), between 2 and 16 m depth. Within cavities net currents averaged 0.9 cm s-1, or 22% of the current speed measured in BBL ~2 m away from the reef. In spite of rapid flushing of cavity waters within a few minutes, we encountered significant chl a and oxygen depletions relative to BBL, particularly under oligotrophic conditions. Chl a depletions amounted, on average, to 0.10 ± 0.03 mg m-3 (median ± median absolute deviation [MAD]) or 54% (max. 86%) of BBL values and showed a positive relation to coelobite suspension feeder densities. Pheopigments, by contrast, remained remarkably constant, indicating selective grazing of the mainly picoplankton-sized food. Oxygen depletions were weak and mainly related to flushing. In sack-shaped cavities they amounted to 13.6 ± 6.1 mmol m-3 or 3 to 9% of BBL concentrations. Analyses of water flow and chl a distributions show that under oligotrophic summer conditions 0.7 g C m-2 d-1 of phytoplankton disappears within the upper 1 m of cavernous reef framework. This conservative estimate is about 1 order of magnitude higher than grazing rates of coral-dominated communities on the exposed reef, rendering cryptofauna suspension feeding an important and new pathway of extrinsic organic matter into coral reefs. KEY WORDS: Cavities · Crevices · Cryptofauna · Coelobites · Phytoplankton · Grazing · Respiration · Coral reefs Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 188. Publication date: November 03, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.
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