Philip Hosegood Ph.D.

It is becoming increasingly clear that marine flora and fauna respond to, and even exploit, changes in water properties and currents. In the Indian Ocean Region, sharks aggregate over seamounts to exploit increased prey abundance resulting from energetic tidal currents. Additionally, the severity of coral bleaching varies over short distances and with depth, reflecting the influence of upwelling events that cool the coral community in key places throughout the archipelago.

Effective conservation strategies need to incorporate our evolving understanding of how marine organisms respond to these changes in oceanographic conditions as their behaviour often creates hotspots of biodiversity and abundance that are critically important to protect. In the Chagos Archipelago, I am using a variety of observational techniques including heavily instrumented oceanographic moorings, vessel-based acoustic surveys, numerical modelling and satellite-based measurements. I aim to assess the extent to which hotspots of animal abundance, especially for apex predators and manta rays, are driven by energetic ocean currents.

Of particular interest are internal waves which also appear to create pockets of resilience in the coral community by flushing the surface corals with cool water, relieving the thermal stress responsible for bleaching. We will assess whether locations where this flushing happens represent potential ‘coral sanctuaries’ that can sustain the wider coral community in future years as ocean warming increases.