Monitoring Coral Reefs in the Indian Ocean
Project Overview
Context
The degree to which a coral reef is considered to be ‘functioning’ is determined by a combination of measures such as coral cover, biomass, diversity, calcification rate and growth.
A key metric in determining reef status and resilience to future stressors is the balance between calcification and erosion which indicates if a reef is growing or eroding.
Monitoring BIOT’s benthic community is essential to the prognosis of the condition of its reef in the near future. It is believed that the back-to-back bleaching events in 2015 and 2016 have greatly altered the reefs’ trajectory.
Funded by
Specifically, our research is extending the existing long-term assessments of coral reef growth, cover, recruitment and functionally extinct corals that have been monitored since 1978 and are of crucial importance to the ecological health of the reefs.
A video archive has been established to assess long term changes in the benthic community resulting from a warming ocean. The increase in ocean temperature results in more frequent disease and bleaching events which impair the health and reproductive capacity of corals and often leads to death of coral. These events cause significant changes in coral community structure and reduces the reefs’ ability to prevent shoreline erosion. Impacts of increased sea temperature can also be observed in species of connected ecosystems. To understand coral resilience to climate change, we are investigating the innate immune response of corals, and integrating long-term sea surface temperature trends into coral reef resilience models. Additionally, the coral reefs of BIOT vary considerably in their aspect, topography and hydrography due to the structure of the different atolls, banks, sea mounts and islands. These factors impact the benthic community and reef resilience and so we are also studying how internal wave-driven upwelling affects the shallow reefs’ resilience to bleaching. These studies will enable us to better understand why some corals are more resilient to bleaching than others.
Coral condition is one of the leading guides to the future condition and trajectory of the BIOT marine environment in our warming world. The British Indian Ocean Territory is an important ocean observatory due to its remote location which shelters it from direct human impact. The Territory acts as a benchmark against which other reefs can be assessed and demonstrates how undisturbed reefs function and respond to climate change, pollution and over-exploitation. This helps to demonstrate the value of BIOT’s MPA and can inform effective improvements in the management of degraded coral reefs in the Indian Ocean and beyond.
The resilience of coral reefs in the Chagos Archipelago to rising sea temperatures has been remarkable. But as the warming events become more severe and more frequent will they keep recovering?
Key Facts
Publications
Quantifying Reef-Derived Sediment Generation: Introducing the SedBudget Methodology to Support Tropical Coastline and Island Vulnerability Studies
Perry, C., Lange, I.D., Stuhr, M. (2023). Quantifying reef-derived sediment generation: Introducing the SedBudget methodology to support tropical coastline and island vulnerability studies. Cambridge Prisms: Coastal Futures.
Mushroom to Manoeuvre? Using Photogrammetry to Track the Movement and Survival of Free-Living Corals
Bayley, D.T.I., Mogg, A.O.M. (2022). Mushroom to manoeuvre? Using photogrammetry to track the movement and survival of free-living corals. Coral Reefs.
Conclusions of Low Extinction Risk for Most Species of Reef-Building Corals are Premature
Muir, P.R., Obura, D.O., Hoeksema, B.W., Sheppard, C., Pichon, M., Richards, Z.T. (2022). Conclusions of low extinction risk for most species of reef-building corals are premature. Nature Ecology & Evolution.
Atoll-Dependent Zonation in Benthic Communities on Remote Reefs
Sannassy Pilly, S., Richardson, L.E., Turner, J.T., Roche, R.C. (2022). Atoll-dependent zonation in benthic communities on remote reefs. Marine Environmental Research.
Vulnerable to Collapse of Coral Reef Ecosystems in the Western Indian Ocean
Obura, D., Gudka, M., Samoilys, M., Osuka, K., Mbugua, J., Keith, D. A., Porter, S., Roche, R., van Hooidonk, R., Ahamada, S., Araman, A., Karisa, J., Komakoma, J., Madi, M., Ravinia, I., Razafindrainibe, H., Yahya, S., Zivane, F. (2022). Vulnerable to collapse of coral reef ecosystems in the Western Indian Ocean. Nature Sustainability.
