Plenary Speakers
Prof Chris Perry
Professor in Tropical Coastal Geoscience at the University of Exeter
Chris' research focuses on addressing questions about the response of tropical coastal and shallow marine ecosystems (specifically coral reefs and coral reef islands) to the impacts of environmental and climatic change. Increasingly this work has been focussed on the consequences of these impacts, and on resultant reef species transitions and biodiversity shifts, for the geo-ecological functions that reefs sustain. These functions include the maintenance of reef structures and reef structural complexity, reef accretion potential and reef-derived sediment supply. Central to addressing these challengers has been the development of two reef status and monitoring tools, ReefBudget and the more recent SedBudget methodologies. Both are census-based and have potential to be integrated within wider reef monitoring programmes.
Changing geo-ecological functionality of western Atlantic reefs: status, trajectories and future options
The ecology of coral reefs across the tropical western Atlantic (TWA) has been changing rapidly. Coral cover, which commonly averaged 50-60% in the 1970’s, now rarely exceeds 15% and is often lower. Key reef-building species including Acropora palmata and A. cervicornis have largely disappeared, and recent disease outbreaks and periods of extreme thermal stress are diminishing remaining coral populations. These transitions are fundamentally changing the capacity of the regions reefs to sustain the key geo-ecological functions of reef framework construction, vertical reef-building and sediment generation. Rates and processes associated with each have changed markedly, with cumulative negative consequences for reef-derived ecosystem services. Our work over the past ~15 years has shown that the carbonate budgets of most TWA reefs have generally collapsed, and that contemporary vertical reef growth rates are well below long-term historical rates. Sources of reef-derived sediment are also changing – with potentially negative consequences for shoreline sediment supply. Future projections of reef growth potential, factoring for climate change impacts on coral cover and calcification, and substrate erosion rates are grim. Existing low coral cover levels will see many reefs becoming net erosional by mid-Century, but if warming reaches 2°C above pre-industrial all reefs are projected to be net eroding by 2100. Water depths above reefs would increase 0.7–1.2 m, elevating coastal flooding risks and modifying nearshore hydrodynamics and ecosystems. Limiting the impacts from these changes will be challenging. Restoration is one option for enhancing reef growth but would need to be highly targeted geographically and (without significant thermal acclimation) realistic in its use of species. This will require a revised view of what successful restoration in the TWA looks like and what it can deliver ecologically and functionally. The need for accompanying urgent actions on carbon emissions and regional marine environmental conditions are a given.
Dr Melita Samoilys
- Director at Coastal Oceans Research and Development in the Indian Ocean, Kenya
Melita was born in Tanzania, educated in Uganda, UK and Australia and is a permanent resident of Kenya. Her MSc and PhD were from Queensland University and James Cook University in Australia. She is an Adjunct Academic Staff at Pwani University, Kilifi, Kenya.
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