declining coral skeletal extension for forereef colonies of siderastrea siderea on the mesoamerican barrier reef system, southern belize下降的珊瑚骨骼forereef殖民地的扩展siderastrea siderea中美洲堡礁体系,伯利兹城南部.pdf

Declining Coral Skeletal Extension for Forereef Colonies of Siderastrea siderea on the Mesoamerican Barrier Reef System, Southern Belize 1 1 2 Karl D. Castillo *, Justin B. Ries , Jack M. Weiss 1 Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America, 2 Curriculum for the Environment and Ecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America Abstract Background: Natural and anthropogenic stressors are predicted to have increasingly negative impacts on coral reefs. Understanding how these environmental stressors have impacted coral skeletal growth should improve our ability to predict how they may affect coral reefs in the future. We investigated century-scale variations in skeletal extension for the slow-growing massive scleractinian coral Siderastrea siderea inhabiting the forereef, backreef, and nearshore reefs of the Mesoamerican Barrier Reef System (MBRS) in the western Caribbean Sea. Methodology/Principal Findings: Thirteen S. siderea cores were extracted, slabbed, and X-rayed. Annual skeletal extension was estimated from adjacent low- and high-density growth bands. Since the early 1900s, forereef S. siderea colonies have shifted from exhibiting the fastest to the slowest average annual skeletal extension, while values for backreef and nearshore colonies have remained relatively constant. The rates of change in annual skeletal extension were 20.020 60.005, 0.011 60.006, and 20.008 60.006 mm yr21 per year [mean6SE] for forereef, backreef, and nearshore colonies respectively. These values for forereef and nearshore S. siderea were significantly lower by 0.031 60.008 and by 0.019 60.009 mm yr21 per year, res