Physiological responses to short-term sediment exposure in adults of the Caribbean coral Montastraea cavernosa and adults and recruits of Porites astreoides

Sedimentation is a common anthropogenic stressor known to reduce coral growth, reproduction, and the photosynthetic capacity of their endosymbiotic algae. This study assessed the short-term effects of sedimentation on the condition and survivorship of Porites astreoides recruits, as well as the photophysiology, oxidative stress, survivorship and recovery potential of adult Montastraea cavernosa and P. astreoides. Porites astreoides recruits were subjected to either fine-grained (grains sizes 250 mu m and smaller) or coarse-grained (grain sizes 1.44 mm and larger) sediments for 48 h. Only coarse-grained sediments significantly reduced the survivorship and condition of recruits. Adult colony survivorship was significantly lower in exposed P. astreoides compared to M. cavernosa colonies. Regardless of sediment treatment, the maximum quantum yield of endosymbionts within adult P. astreoides colonies declined significantly following sediment exposure and did not show any signs of recovery. This response failed to yield any clear changes in oxidative stress activity. In comparison, adult M. cavernosa colonies exposed to high sediment levels showed significant recovery in maximum quantum yield, without any significant changes in oxidative stress, following sediment removal. The results of this study highlight the importance of considering the differential inter- and intra-specific susceptibilities that are encountered in corals as a function of life history stage and gross morphology when exposed to varying sediment grain types.

Automated summary

The study found that sediment of different grain sizes had varying impacts on the survival and condition of Porites astreoides recruits, as well as on adult corals, highlighting the differential susceptibilities within and between species. While coarse-grained sediments significantly reduced survivorship and condition of recruits, adult Montastraea cavernosa showed significant recovery in maximum quantum yield after exposure to high sediment levels.