Volcanic impacts on coral reefs

Abstract

Considering the current coral reef crisis and given the conservation priority of tropical reefs, better understanding of the drivers shaping ecological coral reef resilience is required to direct contemporary management strategies. Despite the relevance of volcanic impacts in shaping coral development throughout evolution, they have received little scientific attention. Here, selected case studies are presented to identify and describe unifying patterns of volcanic implications on coral reef communities. An important volcanic hazard affecting coral reefs is material deposition from tephra fallout, pyroclastic currents, and lava flows. Volcanic activities can directly impact coral reefs by material deposition during eruptive periods, and subsequently alter habitat conditions from local to global scales. Related changes affect water quality and substrate characteristics. Coral reefs cannot form on loose volcanic substrates, whereas stable volcanic bedrock provides important shallow-water habitats to corals and other reef organisms. Volcanically-induced habitat changes may persist for months to millennia depending on hazard intensities, ecological reef state, species composition, and environmental conditions. However, coral communities are able to recover from volcanic impacts and in some instances, can even enhance local reef biodiversity and stimulate species turnover. In this study, critical hazard thresholds of coral reef responses to volcanic impacts from tephra deposition are defined. Integrating those references into probabilistic tephra fall modelling in the Coral Triangle (CT) allowed for hazard quantification in space and time. The CT is a global hotspot of marine biodiversity alongside active volcanism hosts some of the most diverse coral reef communities. In this region, over 42% of coral reefs are likely to be affected by light volcanic impacts within 1,000 years. However, the probabilities for most severe events with tephra deposition of 30 cm and the potential to eliminate entire coral reef communities are low only with 6% of coral reefs potentially affected within a millennia.

Date of Award	23 Mar 2023
Original language	English
Awarding Institution	University of Bristol
Sponsors	European Commission
Supervisor	Erica Hendy (Supervisor), Elena Couce (Supervisor), Susanna Jenkins (Supervisor) & Dan Lunt (Supervisor)