Biosciences Seminar Series - Winter 2018
22 March 2018 - 1pm - Zoology Museum
Ecological drivers and predictors of coral reef carbonate budgets
Dr Fraser Januchowski-Hartley
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| Photo by http://cola.zoom.nl/ |
Our Biosciences Seminar Series continues with a talk by Dr Fraser Januchowski-Hartley, from the Department of Marine Biodiversity, Exploitation and Conservation (MARBEC) at the University of Montepellier (France). Fraser is a marine biologist interested in the effects of traditional fishing and marine management on fish behaviour, and how changes in behaviour impinge on fishery and conservation goals, and more broadly in how local communities interact with coral reefs and on developing ways of co-management of marine protected areas. Fraser grew up in the UK and Malawi and his research has taken him to Fiji, Papua New Guinea, the Philippines, Vanuatu and the Seychelles. His project on investigating carbonate production and bioerosion on Kenyan coral reefs is part of the NERC funded Sustainable Poverty Alleviation from Coastal Ecosystem Services (SPACES) project - a transdisciplinary project aiming to fill critical knowledge gaps regarding how ecosystems contribute to wellbeing and poverty alleviation.
Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. In particular, over the past 50 years there has been global decline in coral cover with associated shifts in the relative abundance of corals with different carbonate production potential. The geomorphic impacts of coral mass mortality and community change have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential.
To address this issue, my research focuses on how coral reef carbonate budgets can be estimated using underwater visual census of both carbonate producing (corals, crustose coralline algae) and eroding (parrotfishes, urchins, clionaid sponges etc.) guilds on coral reefs. First, I will present on how this method has been used to identify the different carbonate production potential of reefs in East Africa across a gradient of human influence, identify which aspects are of primary importance, and what this means for future vertical reef growth in the context of rising sea-levels. Second, I will demonstrate how these methods can be calibrated with widely used census methods at a local scale to estimate historical trends in carbonate budgets where this data exists, with examples from the Seychelles.
We used data covering 20 years and at least one major bleaching event and the ReefBudget census method to identify that relatively high massive coral cover, and low macroalgal cover and abundance of excavating parrotfishes were essential in maintaining positive reef carbonate budgets. Further, we showed that reefs in the Seychelles were trapped into either positive or negative budget trajectories within a decade of bleaching, and that this was likely to persist after the 2016 bleaching event.
To address this issue, my research focuses on how coral reef carbonate budgets can be estimated using underwater visual census of both carbonate producing (corals, crustose coralline algae) and eroding (parrotfishes, urchins, clionaid sponges etc.) guilds on coral reefs. First, I will present on how this method has been used to identify the different carbonate production potential of reefs in East Africa across a gradient of human influence, identify which aspects are of primary importance, and what this means for future vertical reef growth in the context of rising sea-levels. Second, I will demonstrate how these methods can be calibrated with widely used census methods at a local scale to estimate historical trends in carbonate budgets where this data exists, with examples from the Seychelles.
We used data covering 20 years and at least one major bleaching event and the ReefBudget census method to identify that relatively high massive coral cover, and low macroalgal cover and abundance of excavating parrotfishes were essential in maintaining positive reef carbonate budgets. Further, we showed that reefs in the Seychelles were trapped into either positive or negative budget trajectories within a decade of bleaching, and that this was likely to persist after the 2016 bleaching event.
Hope to see many of you - everyone most welcome to attend!
For the list of forthcoming seminars see here
For the list of forthcoming seminars see here
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