Meeting Abstract
Coral bleaching, the breakdown of the obligate symbiosis between the coral host and its single-celled dinoflagellates, is one of the most evident responses to climate change seen across coral reefs. Different types of Symbiodinium, however, are associated with coral hosts that differ in their responses to stress. The reef-building coral, Montipora capitata, associates with symbionts in clade C (bleaching susceptible) and clade D (bleaching tolerant) or both (at the species and colony level), and neighboring colonies exhibited very different responses during a bleaching event in 2015. Presently, it is common practice to collect a single sample fragment to identify the types and densities of Symbiodinium. This method assumes all Symbiodinium exist in equal ratios across the colony, and leaves little room for examining the micro-landscape in regard to host skeletal architecture, flow, and irradiance. This practice impedes our understanding of coral stress response. The dynamic and diverse structural formations of M. capitata may provide specialized microenvironments better suited to particular clades, and therefore we hypothesize that there is significant symbiont variability among and within individual colonies. Here, we examine the landscape of symbionts using two approaches: 1) ITS2 sequence diversity at the community level (3 samples/colony, 3 colonies/site) will be assessed from ten locations around Oahu and 2) ITS2 sequence diversity at individual level assessed in ~50 samples per colony distributed evenly across the five colonies from Kaneohe Bay. Sampling points will be selected using meshes created through structure-from-motion photogrammetry. Assessing the landscape variability of Symbiodinium is a necessary step in examining the ecological advantages that symbionts contribute to the holobiont’s ability to acclimatize and adapt to future climate conditions.
