Temporal dynamics and environmental drivers of health condition of the coral Siderastrea stellata...
Channel: Encontro Recifal Brasileiro
Date: 2020-07-01

Temporal dynamics and environmental drivers of health condition of the coral Siderastrea stellata in tidal pools of Rio Grande do Norte, Brazil

Wildna Fernandes do Nascimento; Edson Aparecido Vieira Filho; Guilherme Ortigara Longo

Increasing ocean temperatures can be very harmful to coral health, causing bleaching and ultimately death of coral colonies. Coastal reefs are under the influence of continental areas and closer to anthropogenic activities, such as inputs of nutrients, pollution, tourism and fishing that combined negatively affect reef health. The coral Siderastrea stellata (Verrill, 1868) is among the main bioconstructors of shallow reefs in Northeastern Brazil, being common in several types of reefs, including coastal tide pools. We assessed the health of S. stellata in a tide pool to understand the temporal dynamic to which these corals are subjected and how it affects their health. We have monitored eleven S. stellata colonies for three years since February 2017, majorly on a twice-a-month basis, in a tide pool in Natal-RN. The colonies were evaluated for the occurrence and proportion of bleaching, paleness, mortality, and burying. We also collected temperature, wind and wave data, to evaluate potential temporal patterns associated to coral health. Most colonies remained healthy over time, except after stress events caused by high temperature and high level of burying, which resulted in up to a 100% of bleached colonies sometimes. Such burying events seem to be related to the directional change of winds and waves, which can lead to a greater deposition (orthogonal to coastline) or removal of sediments (tangential to coastline). Despite the stress caused by environmental variations, the colonies recovered within 30 days into a healthy state, indicating a high resilience. Our results show that burying and high temperature occurring simultaneously can cause serious damage to S. stellata, but the fast recovery of these colonies highlight the resilience of this important shallow reef constructor when facing both global and local impacts.