Presenter: Ana Carolina Grillo
Session: 11C - Shift in scleractinian dominated reefs - are we facing new winners - octocorals, sponges and macroalgae? / Sponges on coral reefs: how can we reconcile contradictory reports on controls, population and community dynamics, and functional roles?
Format: Oral presentation (pre-recorded video)
Non-moving organisms, like corals and algae, commonly compete for space to survive in reef environments using different mechanisms to succeed, including chemical warfare. These organisms can use chemical compounds to compete, with some of them affecting corals only when contacting them physically, while others can reach the competitors without needing physical contact. We conducted an experiment to investigate the responses of two hard coral species to both competition mechanisms, direct contact and proximity to competitors, using a macroalgae and a zoanthid that are commonly observed in the tropical Southwestern Atlantic reefs in Brazil (~5°S). Our experiment showed that macroalgae and zoanthid were only effective competitors upon direct contact, with the zoanthid being a stronger competitor in comparison to the macroalgae. However, the hard corals differed in their responses to the zoanthid and macroalgae regarding their damage and recovery. Given the higher thermal tolerance and growth rates of these competitors, they can be highly detrimental to corals. This is especially relevant in reefs with relatively low coral cover where zoanthids and macroalgae are dominant groups, which is the case of shallow tropical Brazilian reefs.
Contact Ana:
@acmgrillo
@MarineEcoBr