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Settlement success of Favia fragum planulae exposed to different sediment types and concentrations from southern Puerto Rico
Citation:
McGill, C., C. Randall, AND M. Barron. Settlement success of Favia fragum planulae exposed to different sediment types and concentrations from southern Puerto Rico. Presented at ASLO 2013 Aquatic Sciences Meeting, February 17 - 22, 2013.
Impact/Purpose:
Poster depicting sediment effects on coral settlement.
Description:
Sedimentation has been reported to adversely affect coral ecosystems, but the precise effects of sediment on coral larval settlement and metamorphosis are not well understood. Planulae from laboratory-cultured Favia fragum colonies were collected and exposed to sediment collected from shallow marine habitats of Guánica and Peñuelas, Puerto Rico to determine how sediment source, concentration, and grain size affect larval settlement. Newly collected planulae were exposed to whole Guánica and Peñuelas sediment (<500 µm grain size) at six concentrations ranging from 20 to 640 mg/cm2, and to a single concentration (20 mg/cm2) of Peñuelas sediment fractioned into five grain-size categories (<32 µm, 33-63 µm, 64-125 µm, 126-250 µm, and 251-500 µm). Positive controls with no sediment consistently showed 80-100% settlement within 48 hours. Guánica sediment caused a decline in settlement with increasing sediment dose, resulting in a median effective concentration (EC50) of 31.80 mg/cm2. Settlement of planulae exposed to Peñuelas sediment had a more dramatic decline in settlement, exhibiting an EC50 of 1.25 mg/cm2. Planulae exposed to different grain-size classes of 20 mg/cm2 of Peñuelas sediment showed no significant differences in settlement success among fractions. The results of this study indicate that sediment effects on F. fragum settlement can be dependent on both concentration and sediment source but, at least for Peñuelas sediment, not grain size.