MEPS 312:123-139 (2006)  -  doi:10.3354/meps312123

Northern Florida reef tract benthic metabolism scaled by remote sensing

John C. Brock1,*, Kimberly K. Yates1, Robert B. Halley1, Ilsa B. Kuffner1, C. Wayne Wright2, Bruce G. Hatcher3

1U.S. Geological Survey, Center for Coastal and Watershed Studies, 600 4th Street South, St. Petersburg, Florida 33701, USA
2NASA Goddard Space Flight Center, Wallops Flight Facility, Wallops Island, Virginia 23337, USA
3University College of Cape Breton, 1250 Grand Lake Road, Sydney, Nova Scotia B1P 6L2, Canada
*Corresponding author. Email:

ABSTRACT: Holistic rates of excess organic carbon production (E) and calcification for a 0.5 km2 segment of the backreef platform of the northern Florida reef tract (NFRT) were estimated by combining biotope mapping using remote sensing with community metabolic rates determined with a benthic incubation system. The use of ASTER multispectral satellite imaging for the spatial scaling of benthic metabolic processes resulted in errors in E and net calcification (G) of 48 and 431% respectively, relative to estimates obtained using AISA hyperspectral airborne scanning. At 19 and 125%, the E and G errors relative to the AISA-based estimates were less pronounced for an analysis that used IKONOS multispectral satellite imagery to spatially extrapolate the chamber process measurements. Our scaling analysis indicates that the holistic calcification rate of the backreef platform of the northern Florida reef tract is negligible at 0.07 g CaCO3 m-2 d-1. All of the mapped biotopes in this reef zone are net heterotrophic, resulting in an estimated holistic excess production rate of -0.56 g C m-2 d-1, and an overall gross primary production to respiration ratio of 0.85. Based on our finding of ubiquitous heterotrophy, we infer that the backreef platform of the NFRT is a sink for external inputs of suspended particulate organic matter. Further, our results suggest that the inward advection of inorganic nutrients is not a dominant forcing mechanism for benthic biogeochemical function in the NFRT. We suggest that the degradation of the northern Florida reef tract may parallel the community phase shifts documented within other reef systems polluted by organic detritus.

KEY WORDS: Coral reefs · Benthic metabolism · Remote sensing · Lidar · Northern Florida reef tract

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