HEALTH AND TAPHONOMY OF TELEPHONE POLE REEF (SAN SALVADOR ISLAND, BAHAMAS) IN 2008: A MODEL FOR RECOGNIZING RAPID REEF TRANSITIONS PRESERVED IN THE FOSSIL RECORD

Telephone Pole Reef, a patch reef on the leeward side of San Salvador Island, Bahamas, has undergone rapid species turnover in the past two decades, and the health of the current dominant coral species continues to decline. In June of 2008, Porites porites coral colony surfaces at Telephone Pole Reef were systemically observed, photographed and sampled. Following the techniques used in 1993, 1998, and 2000 surveys of the same reef (Curran et al., 2000), the percentage of living P. porites was both visually estimated on-site and calculated from photographic area analysis of each of 12 mapped colonies. Although Ristau (1998) categorized each of these colonies as Fair (50-75% living) to Excellent (>95% living) just ten years prior, analysis of the reef corals in 2008 placed all of these colonies in either the Poor (<50% living) or Dead (<5% living) categories. Although the upper surfaces of these colonies are mostly dead, surviving polyps are concentrated on the undersides of branches (hidden from area analysis) and in low, marginal portions of the upper colony surface. Branches in the high central portion of each domal colony are generally coated with 1.4-9.7 mm-thick encrustations of coralline algae, foraminifera and calcified microbial filaments, which thicken upward along the coral branches. The remaining dead upper portions of the colonies are covered with numerous species of branching and leafy macroalgae, and a few young recruits of Montastrea annularis and Porites astreoides corals. A few healthy young P. porites recruits were found in the lowest crevasses between older colonies and in a few shallow overhangs below M. annularis heads. Comparative examination of in situ fossil P. porites present in the Sangamonian reef deposits at Sue Point (San Salvador Island) reveal similarities in several taphonomic features (minor abrasion and boring, and fairly thick coralline algal/foram/microbial coatings).

In addition to previously suggested causes (loss of herbivores and nutrification), living-dead distributions suggest that UV radiation could also contribute to P. porites demise at Telephone Pole Reef. Regardless of the specific cause(s) of death, comparison of modern and ancient P. porites indicates similar species transitions and taphonomic features, like those recognized in other Late Pleistocene reef deposits.