New Publication: Kenyan and Mozambican coral reef ‘carbonate budgets’ contribute to international picture of corals under sea-level rise.
SPACES coral reef surveys have contributed to an international picture of how reefs might be able to grow to keep up with sea-level rise, recently published in Nature.
The growth of coral reefs is strongly influenced by the amount and types of coral living on the reef surface, but across both regions this growth is now being hampered by combinations of coral disease, deteriorating water quality and fishing pressure, along with severe impacts from “coral bleaching” caused by climate change. By counting the organisms responsible for building up and eroding reefs, SPACES team members Chris Perry and Fraser Januchowski-Hartley have been able to calculate the ‘carbonate budget’ and estimate how quickly reefs can grow towards the surface (the ‘accretion rate’).
In the figure below, the Mozambican (17) and Kenyan (18) SPACES sites can be seen in comparison to reefs from around the Indian ocean and Western Atlantic. The poorest reefs in […]
Changing dynamics of reef framework production in the Western Indian Ocean – Fraser Januchowski-Hartley et al.(1.2 MB)
Fraser Januchowski-Hartley’s presentation at the 2015 WIOMSA symposium on carbonate budget and current coral condition at SPACES sites, Mombasa, Shimoni, Vamizi, and Pemba.
Remote coral reefs can sustain high growth potential and may match future sea-level trands. Nature Scientific Reports 2015
Climate-induced disturbances are contributing to rapid, global-scale changes in coral reef ecology. As a consequence, reef carbonate budgets are declining, threatening reef growth potential and thus capacity to track rising sea-levels. Whether disturbed reefs can recover their growth potential and how rapidly, are thus critical research questions. Here we address these questions by measuring the carbonate budgets of 28 reefs across the Chagos Archipelago (Indian Ocean) which, while geographically remote and largely isolated from compounding human impacts, experienced severe (>90%) coral mortality during the 1998 warming event. Coral communities on most reefs recovered rapidly and we show that carbonate budgets in 2015 average +3.7 G (G = kg CaCO3 m−2 yr−1). Most significantly the production rates on Acropora-dominated reefs, the corals most severely impacted in 1998, averaged +8.4 G by 2015, comparable with estimates under pre-human (Holocene) disturbance conditions. These positive budgets are reflected in high reef growth rates (4.2 mm yr−1) on Acropora-dominated reefs, demonstrating that carbonate budgets on these remote reefs have recovered rapidly from major climate-driven disturbances. Critically, these reefs retain the capacity to grow at rates exceeding measured regional mid-late Holocene and 20th century sea-level rise, and close to IPCC sea-level rise projections through to 2100.
How important are parrotfish for coral reef islands?
Parrotfishes are a beautiful, colourful and ubiquitous group of fishes that are present on coral reefs around the world. They’ve received a lot of attention due to their importance in both fisheries, and in how they can help to maintain coral reef health through preventing outbreaks of fleshy macroalgae, that can overgrow and out-compete corals. However, one role that parrotfish are particular important in playing on coral reefs has been somewhat overshadowed. A new study, published in Geology led by Prof Chris Perry, part of the SPACES team, has identified the pivotal role parrotfishes play to build and maintain coral reef islands.
Using survey and sedimentary data the study, coauthored by Paul Kench, Michael O’Leary, Kyle Morgan, and Fraser Januchowski-Hartley (who is also from the SPACES […]