School of Natural and Environmental Sciences

Event items

Back to the future: analyses of coral reef island evolution and vulnerabilities under environmental change, Huvadhoo Atoll, Maldives

Earth, Ocean and Planetary Sciences Seminar Series - Dr Holly East, Northumbria University

Date/Time: Thursday 10 January, 13:00 - 14:00

Venue: Ridley Building 2, Room 1.48

Abstract

Coral reef islands are regarded among the world’s most vulnerable environments to climate change because they are low-lying (typically <3 m above mean sea level) and formed entirely of sediment produced by organisms in adjacent coral reef communities. 

There is thus major concern over the future existence and habitability of atoll nations, within which reef islands provide the only habitable land. However, despite this concern, existing datasets are currently insufficient to allow confident projections of future reef island trajectories.

Here, we present a holistic study of reef island vulnerability on Huvadhoo Atoll rim, southern Maldives. 

Specifically, we:

  • reconstruct reef island formation and evolution in relation to past changes in sea level
  • analyse contemporary connectivity between reef ecology and reef island building processes
  • model future reefal sediment transport under different sea level rise scenarios

Results demonstrate that reef island building actually occurred under higher than present sea levels, during the mid-Holocene sea level highstand. 

In addition, excavator parrotfish were identified as the dominant sediment producers, accounting for 79.4% of the total annual production.

Hence, any shifts in excavator parrotfish abundance and spatial distribution could thus have a critical impact upon reef island resilience in the face of future environmental change.

Furthermore, modelling results indicate reef islands may undergo lagoonward migration, as opposed to inundation, under sea level rise scenarios. 

Collectively, results indicate that reef islands may be more resilient to environmental change than has previously been assumed.