δ13C and δ15N stable isotopes demonstrate seasonal changes in the food web of coral reefs at the Wuzhizhou Island of the South China sea

Abstract

With a high species diversity of coral reefs, Wuzhizhou (WZZ) is a tropical marine ranch built by China. In the present study, we investigated the structure and function of coral reef food webs on WZZ in Sanya to understand how climate change and human activities affected coral reef ecosystems. Using carbon and nitrogen stable isotopes and the Bayesian mixture models, we assessed the major organic matter pathways and causes of seasonal variation in coral reef fauna and isotope values to delineate ecosystem function. Macroalgae and benthic microalgae were the primary food sources feeding this food web, while there were also some notable seasonal variations. Nutrient changes caused by temperature, upwelling, and tropical cyclones might be the primary reasons for the changes in consumer community composition and carbon or nitrogen isotopes. Seasonal environmental changes did not affect the stability of the nutrient structure of the coral reef food web on WZZ.