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 both countries have a zero or even negative growth rate, while some of best reefs show some the highest accretion rates measured in the Indian Ocean…
Meanwhile, rates of sea-level rise are increasing – and the results suggest the most reefs will be unable to keep up. As a result, water depths above most reefs are projected to increase rapidly through this century. This figure from the paper shows expected deepening of water over the reefs under more moderate (RCP4.5) and more severe (RCP4.5) scenarios of climate change.
Like most sites in the dataset, the SPACES sites mostly show a deepening, with only a few reefs in each country projected to be able to keep up with sea-level rise even under modest projections. The poorest reefs under the higher climate change scenarios are projected to become up to 80cm deeper.
This is of critical concern because reefs play a key role as natural sea defences by limiting coastal wave energy exposure. The study concludes that efforts to tackle climate change must be coupled with careful management of fishing and water quality protection to prevent widespread submergence through this century.
the full paper is here:
Perry et al. (2018) Loss of coral reef growth capacity to track sea-level rise under climate change. Nature.
…and a more popular summary here:
New publication drawing on SPACES data shows East African reefs particularly susceptible to coral bleaching
SPACES team members, Tim McClanahan and Nyawira Muthiga have used SPACES coral reef survey data in an analysis of the factors affecting coral’s susceptibility to coral bleaching in the face of warmer climates. The analysis based on surveys from E. Africa to Fiji during the 2016 El Nino event showed that bleaching is caused by […]
Artisanal fisheries in Cabo Delgado, Mozambique: rural vs urban fishing centers
This working paper investigates the relationship between gear, catch and income generated by the fishers in different seasons. SPACES researchers collected data using fish catch surveys at landing sites in Pemba town, Vamizi and Lalane. A standard questionnaire was used to collect the effort and location of the fishery. The fishery shows a wide range […]
Nereus Report: Predicting Future Oceans — Climate Change, Oceans & Fisheries
A report entitled “Predicting Future Oceans: Climate Change, Oceans & Fisheries” newly released by the Nereus program, an international interdisciplinary research program aimed at predicting future oceans, suggests that future seafood supply in the world will be substantially altered by climate change, overfishing and habitat destruction if we do not take actions.
Application of IPCC guidelines in monitoring, reporting and verification (MRV) of blue carbon in WIO countries – Lilian Mwihaki et al.(8.8 MB)
WIOMSA presentation on the concept on the evolution of climate change science and the limitations of the Intergovernmental Panel on Climate Change (IPCC). The Blue Carbon initiative created an internationally applicable standard for quantifying and measuring coastal carbon. The presentation finishes with recommendations for the way forward.
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.
Linking reef ecology to island building: Parrotfish identified as major producers of island-building sediment in the Maldives. Geology 2015
Reef islands are unique landforms composed entirely of sediment produced on the surrounding coral reefs. Despite the fundamental importance of these ecological-sedimentary links for island development and future maintenance, reef island sediment production regimes remain poorly quantified. Using census and sedimentary data from Vakkaru island (Maldives), a sand-dominated atoll interior island, we quantify the major […]
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 […]
Similar impacts of fishing and environmental stress on calcifying organisms in Indian Ocean coral reefs. Marine Ecology Press Series 2016
Calcification and reef growth processes dominated by corals and calcifying algae are threatened by climate and fishing disturbances. Twenty-seven environmental, habitat, and species interaction variables were tested for their influence on coral and calcifier cover in 201 western Indian Ocean coral reefs distributed across ~20° of latitude and longitude and up to 20 m deep. […]
Environmental variability indicates a climate-adaptive center under threat in northern Mozambique coral reefs. Ecosphere 2017
A priority for modern conservation is finding and managing regions with environmental and biodiversity portfolio characteristics that will promote adaptation and the persistence of species during times of rapid climate change. The latitudinal edges of high-diversity biomes are likely to provide a mixture of environmental gradients and biological diversity that meet the portfolio criteria needed […]
Drivers and predictions of coral reef budget trajectories. Proceedings Of The Royal Society B-biological Sciences 2017
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 […]
Ecological Underwater Surveys
All information including publications, conference presentations and news items related to underwater ecological surveys is tagged below.
New paper from SPACES team members shows the positive correlation between the orange-lined triggerfish and calcifier cover
SPACES Co-investigators, Tim McClanahan and Nyawira Muthiga, have recently published the paper, Similar impacts of fishing and environmental stress on calcifying organisms in Indian Ocean coral reefs (Open Access– free to read) in the Marine Ecology Progress Series. They investigated coral and calcifier cover in 201 western Indian Ocean reefs. McClanahan and Muthiga found that coral and calcifier cover […]
Aligning Global Indicators for Coral Reef Fisheries Monitoring in the Western Indian Ocean Workshop
Recently, a member of the SPACES team attended a regional workshop in Nosy Be, Madagascar from 27 to 28 April, 2015. The workshop was convened by the Wildlife Conservation Society (WCS) and Dr Emily Darling with the aim to bring together various researchers working on coral reef fisheries in the Western Indian Ocean (WIO). The workshop […]
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. […]