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Barnard Castle, United Kingdom

Dunne R.P.,West Briscoe
Coral Reefs | Year: 2010

Throughout the coral reef scientific literature, there are many examples where the words 'synergy' and 'synergism' are being misused, particularly in the area of study involving interactions between physical stressors. This Perspective discusses the concept of synergy and more generally, interactions; summarises the tools available for detecting and interpreting interactions, including the use of ANOVA, generalized linear models, classification and regression trees and isobolographic analysis; and critically examines specific areas of the scientific literature where synergy has been reported. The aim is to promote further discussion of this topic, avoid future misuse of the term, and assist future experimental design and research into this subject. © Springer-Verlag 2009.

Tanzil J.T.I.,National University of Singapore | Tanzil J.T.I.,University of Amsterdam | Tanzil J.T.I.,Singapore MIT Alliance in Research and Technology | Brown B.E.,Northumbria University | And 5 more authors.
Global Change Biology | Year: 2013

This study reports the first well-replicated analysis of continuous coral growth records from warmer water reefs (mean annual sea surface temperatures (SST) >28.5 °C) around the Thai-Malay Peninsula in Southeast Asia. Based on analyses of 70 colonies sampled from 15 reefs within six locations, region-wide declines in coral calcification rate (ca. 18.6%), linear extension rate (ca. 15.4%) and skeletal bulk density (ca. 3.9%) were observed over a 31-year period from 1980 to 2010. Decreases in calcification and linear extension rates were observed at five of the six locations and ranged from ca. 17.2-21.6% and ca. 11.4-19.6%, respectively, whereas decline in skeletal bulk density was a consequence of significant reductions at only two locations (ca. 6.9% and 10.7%). A significant link between region-wide growth rates and average annual SST was found, and Porites spp. demonstrated a high thermal threshold of ca. 29.4 °C before calcification rates declined. Responses at individual locations within the region were more variable with links between SST and calcification rates being significant at only four locations. Rates of sea temperature warming at locations in the Andaman Sea (Indian Ocean) (ca. 1.3 °C per decade) were almost twice those in the South China Sea (Pacific Ocean) (ca. 0.7 °C per decade), but this was not reflected in the magnitude of calcification declines at corresponding locations. Considering that massive Porites spp. are major reef builders around Southeast Asia, this region-wide growth decline is a cause for concern for future reef accretion rates and resilience. However, this study suggests that the future rates and patterns of change within the region are unlikely to be uniform or dependent solely on the rates of change in the thermal environment. © 2013 John Wiley & Sons Ltd.

Brown B.E.,Northumbria University | Brown B.E.,University of the Highlands and Islands | Dunne R.P.,West Briscoe | Phongsuwan N.,Phuket Marine Biological Center | And 2 more authors.
Coral Reefs | Year: 2014

The reef coral Goniastrea aspera is regarded as one of the most environmentally tolerant species on Indo-Pacific reefs. Its demise, following a severe bleaching event in the Andaman Sea in the north-eastern Indian Ocean in 2010, was surprising in view of the rapid recovery of co-existing species such as Porites lutea. Demographic studies of G. aspera at this site showed the population was mainly composed of large individuals, which recruited in the early 1990s. These results, and size-specific mortality observed in G. aspera, post-bleaching, suggest that factors, related to size and age, may have contributed to the coral's marked decline. © 2014 Springer-Verlag Berlin Heidelberg.

Dunne R.P.,West Briscoe | Barbosa S.M.,University of Lisbon | Woodworth P.L.,National Oceanography Center
Global and Planetary Change | Year: 2012

Long term mean sea level in the Chagos Archipelago has been relatively stable over the ~20year length of the available instrumental records. Tide-gauge data from Diego Garcia (1988-2000, and 2003-2011) show no statistically significant long-term rise, whilst the rates of rise obtained from the satellite altimeter record for 1993-2011 span the range of 0.16-4.56mmyr -1 in the surrounding sea areas (70-74°E and 4-9°S) and are also consistent with a zero rate except in the far south of the region. The dominant feature is one of considerable inter-annual variability in mean sea level of up to ~10cm, such that the very weak seasonal pattern of highest and lowest sea level in February and May respectively, is absent or reversed in some years. The Indian Ocean Dipole appears to exert an important influence on mean sea level in the area, with positive and negative dipole mode indices preceding periods of elevated or lowered sea levels respectively. The Chagos also lie outside the Indian Ocean cyclone belt and experience relatively low wind speeds, and there is no evidence of changes in the wind or wave environment in the past 20years. Although in an area of seismic activity, there is no record of island subsidence, indeed on Diego Garcia minor crustal uplift of 0.63±0.28SEmmyr -1 has occurred between 1996 and 2009. Collectively, these results suggest that this has been a relatively stable physical environment, and that these low-lying coral islands should continue to be able to support human habitation, as they have done for much of the last 200years. Nonetheless, future sea-level rise and its effect on the Chagos remains an important issue for further studies such as those of the Intergovernmental Panel on Climate Change. © 2011 Elsevier B.V.

In 2010, coral bleaching at Phuket, Thailand was accompanied by monthly mean sea temperatures that were elevated above a proposed bleaching threshold of 30.11°C for four months from March to June. This extended warm period was accurately identified in both HadSST2 and IGOSS sea surface temperature datasets, but not the HadISST1.1 data which consistently under-recorded the true temperature by up to 1.38°C. HadISST1.1 also failed to differentiate between the 2010 hiatus and the same period in 1998, when less severe butwidespread bleaching occurred. In both cases, had the HadISST1.1 data been relied upon to predict or explain the bleaching severity it would have produced an incorrect result. Although the error may only be a one-off event, nonetheless it highlights the caution that should be exercised when using remotely sensed, temperature datasets, even from seemingly reliable and trusted sources.

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