Effects of monsoon-driven wave action on coral reefs of Guam and implications for coral recruitment

7 páginas, 3 figuras, 1 tablaBenthic cyanobacteria can respond rapidly to favorable environmental conditions, overgrow a variety of reef organisms, and dominate benthic marine communities; however, little is known about the dynamics and consequences of such cyanobacterial blooms in coral reef ecosystems. In this study, the benthic community was quantified at the time of coral spawnings in Guam to assess the substrate that coral larvae would encounter when attempting settlement. Transects at 9, 18, and 25-m depths were surveyed at two reef sites before and after heavy wave action driven by westerly monsoon winds. Communities differed significantly between sites and depths, but major changes in benthic community structure were associated with wave action driven by monsoon winds. A shift from cyanobacteria to crustose coralline algae (CCA) accounted for 44% of this change. Coral recruitment on Guam may be limited by substrate availability if cyanobacteria cover large areas of the reef at the time of settlement, and consequently recruitment may in part depend upon wave action from annual monsoon winds and tropical storms which remove cyanobacteria, thereby exposing underlying CCA and other substrate suitable for coral settlement.This is contribution number 134 of the US ECOHAB program, 576 of the University of Guam Marine Laboratory, and 617 of the Smithsonian Marine Station at Fort Pierce. This work was partially supported by the US Environmental Protection Agency grant R82- 6620 through the ECOHAB program, but it does not necessarily reflect the views of the Agency.Peer reviewe