Coral mortality and recovery in response to increasing temperature in the southern Arabian Gulf

Abstract

Analysis of a new data set for sea surface temperature shows that the seawater temperature rise in 1998 in the southern Arabian Gulf was the largest since 1870; it also showed that there is an underlying rising trend of sea surface temperature across the whole of the measured area spanning 5 degrees longitude and 3 degrees latitude. Over the last 50 years, sea surface temperature rise was about 0.2 ± C per decade, though this has accelerated to about 0.45 ± C per decade in the last 20 years. The pattern in temperature values in each 1 degree 'cell' are used to show that, at any one time, temperature rises towards the east of this area, which supports the concept of a general anti-clockwise circulation in the southeastern half of the Arabian Gulf. Spatial and temporal patterns in sea surface temperature rises also show that the mean temperature eld at any location is similar to that which existed in the one degree cell immediately to its east approximately 30 years earlier.Coral cover in shallow water (<3 m depth) was <1 percent immediately following the 1998 event, due to near total mortality of vast areas of shallow Acropora (stagshorn) corals. Deeper than 3 m there was increasing survival of the large Porites ( boulder) corals, survival increasing with depth. Coral survival improved towards the east, though overall, less than twenty coral species were found altogether. Juvenile recruitment also increased towards the east, and at any one site, recruitment increased with increasing depth. The identity of new juveniles was mainly faviid corals, not the Acropora or Porites which dominated these reefs before the 1998 event. This suggests that there may be a phase shift to a different stable state in terms of coral communities. We also speculate that, because the Arabian Gulf contains an extreme warm-tolerant subset of the Indian Ocean coral fauna, the changes seen in the Gulf may re ect future patterns across a greater part of the Indian Ocean.

A Century of Ocean Warming on Florida Keys Coral Reefs: Historic In Situ Observations

“…The closest fixed site, long-term dataset we know of to our sites is that of Winter et al (1998) at La Parguera, Puerto Rico; the warming trend observed there in the summer maximum SST, from 1966 to 1995, was 0.7°C. Additionally, Sheppard and Loughland (2002) found a remarkably similar 0.9°C warming in the subtropical Arabian Gulf from 1980 to 2000.…”

Spatial and temporal dynamics of Arabian Gulf coral assemblages quantified from remote-sensing and in situ monitoring data

“…Resale or republication not permitted without written consent of the publisher the Arabian Gulf has been intensely studied in this respect and several ancillary studies documenting the biological and geological dynamics of reef building exist for the Arabian Gulf (Shinn 1976, Sheppard et al 1992, Sheppard & Loughland 2002, George & John 1999 and the present study area, Jebel Ali (Riegl 1999(Riegl , 2001(Riegl , 2002.…”

“…In the Arabian Gulf, corals have been persisting in probably the most stressful environment for reef-building corals (Kinsman 1964, Downing 1985, Sheppard et al 1992, Riegl 2001, Sheppard & Loughland 2002. Additional to annual temperature excursions of up to 20°C, marine biota in the Arabian Gulf have been affected by several strong sea-surface temperature (SST) anomalies and associated coral bleaching events (1996,1998,2002).…”

Settlement Patterns of Corals and other Benthos on Reefs with Divergent Environments and Disturbances Histories around the Northeastern Arabian Peninsula

“…In addition, these reefs have experienced numerous large-scale bleaching events over the past two decades (Riegl and Purkis, 2015), resulting in widespread shifts in benthic community structure from which there has been only limited recovery (George and John, 2000;Sheppard and Loughland, 2002;Burt et al, 2008Burt et al, , 2011. In the wake of earlier mass bleaching events, coralline algae dramatically increased in abundance on southern Gulf reefs John, 2000, 2002).…”