role of zooplankton on coral physiology and ecology

• Online Access: http://hdl.handle.net/2047/D20328158

Coral health is threatened by increasing water temperatures causing more frequent and higher intensity bleaching events. This dissertation investigates the role of zooplankton on coral health in Bocas del Toro, Panama. While previous studies have shown certain coral species are able to survive bleaching events through heterotrophic plasticity, little focus has been placed on the role of zooplankton themselves in the natural setting on coral reefs. The following dissertation describes spatial and temporal changes in zooplankton communities accessible to corals, and whether an increased abundance of the natural zooplankton community will provide faster recovery to Porites furcata after a heat-stress event. The highest zooplankton abundances and diversity of zooplankton taxa occurred on the offshore site in fall 2016. No differences in abundance were seen between sites during winter 2017. The enhanced feeding experiment showed that symbiont metrics, including symbiont density, chlorophyll concentrations, and photosynthetic efficiency were not significantly different across feeding treatments of heat-stressed corals. However, the ambient temperature enhanced fed treatment showed an increase in symbiont metrics compared to other treatments, except for photosynthesis rates, which decreased and were lower than all other treatments. This could be explained by P. furcata's ability to decouple its heterotrophic and autotrophic capabilities and capitalize on the enhanced zooplankton availability. No significant differences were found between treatments on the coral host physiology at the end of the five-week recovery. Therefore, the natural conditions of the nearshore coral reef, provide the necessary resources for corals to recover from heat-stress in five weeks.