Tolerance of Brazilian brain coral Mussismilia braziliensis to sediment and organic matter inputs

In Brazil, where reefs occur in markedly turbid environments, the relationship between sedimentation/ organic matter and corals is poorly known. Thus, the ex situ effects of sediment with and without organic matter over the Delta F/Fm and physical state of Mussismilia braziliensis were analyzed. The Delta F/Fm and coral physical state, evaluated through the susceptibility index to sedimentation (SI), were measured in seven colonies exposed to sedimentation (0-450 mg cm(-2) day(-1)) free of organic matter after 45 days of exposure, and in 12 colonies exposed to sedimentation (0-500 mg cm(-2) day(-1)) with organic matter content (10%), in which case Delta F/Fm was measured after 72 h and SI after 120 h. In both cases there were effects of increasing sedimentation on the SI with no effect on Delta F/Fm. Despite the tolerance to high sedimentation rates shown by this coral, we noted that the presence of organic matter might reduce its tolerance to sedimentation stress. (C) 2013 Elsevier Ltd. All rights reserved.