Coral reef growth and geomorphology. y. Understanding past rates and patterns of coral reef growth is essential in order to contexturalise current reef change dynamics. Our research in this area focused explicitly on improving understanding of the timing and rates of coral reef growth through the Holocene and, especially, on patterns of reef development under marginal marine environmental conditions. This has included a substantial body of research dealing with Holocene reef development under conditions of naturally high turbidity and high terrigenous sediment input. Major projects have included studies funded by the Royal Society and Nuffield Foundation on contemporary reef geomorphology and reef growth in high terrigenous sediment-influenced settings in southern Mozambique (Perry, 2003; 2005), and an extensive body of research since 2004 (funded by NERC and the Leverhulme Trust) on turbid-zone, nearshore reef development along the central Great Barrier Reef coastline in Australia. This has included work developing palaeoecological coral assemblage baseline records (Perry et al., 2008, 2009) and assessments of the timescales of reef initiation and demise (Perry & Smithers, 2010). Most recently this work has been expanded to encompass regional scale assessments of mid-late Holocene reef turn-on and turn-off events (Perry & Smithers, 2011) – work that has important implications for understanding modern reef ecological states and near-future trajectories. NERC Urgency grant funding has also supported assessments of the effects of Cyclone Yasi (Feb 2011) on these nearshore reefs (Perry et al. 2014). On-going work, through NERC funding, is undertaking high resolution mapping of nearshore reef communities and developing combined geo-ecological models of inner-shelf reef evolution and change.
Reef island geomorphology and change. Coral reef islands are low-lying accumulations of biogenically-derived sediments. They are highly significant for a range of socio-economic and ecological reasons, but also regarded as being highly vulnerable to sea level and environmental change. Research within our group is focused on developing an enhanced understanding of the timing and modes of reef island development, with a specific current focus on island development within the Maldives. Through recent work undertaken under the auspices of an International Association of Geomorphologist’s Working Group REEForm, and part-funded by NERC, we have developed a new conceptual framework within which to consider the evolutionary stages of reef platform development and a means for assessing the thresholds at which islands may establish and form in the Maldives (Perry et al. 2012). On-going work is now expanding these ideas, to include novel assessments of the age and structure of atoll rim islands in the southern part of the Maldives chain, and work at these and other sites examining the nature of the sediment supply links between islands and their surrounding coral reefs.
Tropical marine carbonate production. Coral reefs are experiencing an unprecedented decline in their abundance, diversity, and habitat structures. On these degrading reefs there is a pressing need to better understand the impacts on budgets of carbonate production and erosion, since these control reef growth potential and reef structural integrity. There is also a paucity of data on many key aspects of tropical marine carbonate sediment production. Research within our group is helping to address some of these knowledge gaps. In particular, we have led on a recent Leverhulme Trust International Research Network that has developed field-based methodologies (ReefBudget) to support assessments of carbonate production states on coral reefs (Perry et al. 2012). Novel regional scale assessments across the Caribbean, as part of this work, suggest significantly reduced rates of carbonate production compared to historical and geological averages, and point to major changes in reef geomorphic functionality (Perry et al. 2013). Through current ESPA funding this approach and methodology is now being extended to the Indian Ocean. We have also led on highly novel research funded through two recent NERC grants which have examined the production of fish-derived carbonate precipitates within both shallow tropical marine and open ocean environments (Perry et al. 2011), and now being extended through new NERC funding to include assessments of carbonate production across latitudinal gradients in Eastern Australia. Previous work in this general area of study has also included Leverhulme Trust funded work on Indian Ocean carbonate platform development (O’Leary and Perry, 2010) and platform sediment facies development (O’Leary et al. 2009; Perry & Berkeley, 2009), and Royal Society funded work on rates and patterns of carbonate production in high latitude seagrass environments (Perry & Beavington-Penney, 2005).