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Effects of algal turf canopy height and microscale substratum topography on profiles of flow speed in a coral forereef environment
Author(s) -
Carpenter Robert C.,
Williams Susan L.
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.3.0687
Subject(s) - microscale chemistry , canopy , coral , environmental science , oceanography , flow (mathematics) , atmospheric sciences , geology , hydrology (agriculture) , ecology , biology , physics , mechanics , geotechnical engineering , mathematics , mathematics education
Water motion can be an important variable affecting the recruitment, metabolism, growth rates, feeding efficiency, and distribution of aquatic organisms. Recent studies suggest that flow speed may be an important factor regulating primary productivity of reef algal turf communities. We measured profiles of flow speed over algal turfs with different canopy heights and over algal turfs growing on substrata that varied in microtopography. Profiles over sea urchin‐grazed algal turfs with low canopy heights and algal turfs growing on topographical high points indicate that the boundary layer is dominated by turbulent eddies. In contrast, flow over algal turfs with higher canopy heights and those growing within depressions in the substratum is influenced more by viscous forces that may lead to diffusion‐limited metabolism of these algal communities. These data demonstrate that flow speeds over coral reef algal turfs exhibit spatial variation over small spatial scales and temporal variation that is dependent on ambient flow speeds. Our results predict microscale variation in algal turf metabolism and suggest that photosynthetic rates of this component are likely to be below maximum capacity for a significant portion of the time.