Additive negative effects of anthropogenic sedimentation and warming on the survival of coral recruits

Corals worldwide are facing population declines due to global climate change and local anthropogenic impacts. Global climate change effects are hard to tackle but recent studies show that some coral species can better handle climate change stress when provided with additional energy resources. The local stressor that most undermines energy acquisition is sedimentation because it impedes coral heterotrophic feeding and their ability to photosynthesize. To investigate if reducing local sedimentation will enable corals to better endure ocean warming, we quantitatively assessed the combined effects of increased temperature and sedimentation (concentration and turbidity) on the survival of coral recruits of the species, Porites astreoides. We used sediment from a reef and a boat basin to mimic natural sediment (coarse) and anthropogenic (fine) sediment (common in dredging), respectively. Natural sediment did not negatively impact coral survival, but anthropogenic sediment did. We found that ...