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Genotypic characterization of Symbiodinium symbionts in hard corals has routinely involved coring, or the removal of branches or a piece of the coral colony. These methods can potentially underestimate the complexity of the Symbiodinium community structure and may produce lesions. This study demonstrates that microscale sampling of individual coral polyps provided suYcient DNA for identifying zooxanthellae clades by RFLP analyses, and subclades through the use of PCR amplification of the ITS-2 region of rDNA and denaturing-gradient gel electrophoresis. Using this technique it was possible to detect distinct ITS-2 types of Symbiodinium from two or three adjacent coral polyps. These methods can be used to intensely sample coral-symbiont population/communities while causing minimal damage. The effectiveness and fine scale capabilities of these methods were demonstrated by sampling and identifying phylotypes of Symbiodinium clades A, B, and C that co-reside within a single Montastraea faveolata colony. [ABSTRACT FROM AUTHOR]

Effects of ambient ultraviolet light on the survivorship of eggs and planulae larvae was investigated for three species of broadcast-spawning reef corals, Acropora palmata, Montastraea annularis, and M. franksi. Eggs and larvae from these corals contain high concentrations of lipids (60–70% by weight) and float in surface waters for 3–4 days following spawning. Larvae originating from colonies living at deeper sites on the reef exhibited significantly lower survivorship than conspecifics originating from parents in shallow water when experimentally exposed for up to 4 days to ambient surface levels of ultraviolet radiation (UVR). Concentrations of the UVR-protective compounds correlated positively with survival and matched concentrations found in parent colonies, implying that higher concentrations of ultraviolet B protective compounds are responsible for greater survival of eggs and larvae from shallow compared to deeper-dwelling parents. Ultraviolet B appears to be responsible for most of the observed differences in larval survivorship with ultraviolet A playing a minor or insignificant role. Data presented here indicate that coral recruits on Caribbean reefs and elsewhere may originate primarily from adult colonies dwelling in shallow water. [ABSTRACT FROM AUTHOR]

The gastropod genus Conus is shown to be among many marine taxa thatattain maximal known diversity along the northeast coast of Papua New Guinea. Thirty-six species co-occurred on the reef platform fringing Laing Island in Hansa Bay, 33% more than previously documented on any single reef. Near Madang, 32 species occurred on four small reefs.Maximal density at both sites was 3/m2, with overall density 0.1-0.2/m2. Species richness, diversity, and general patterns of microhabitat use were similar at both, but composition differed markedly. Only 23 species were found at both sites, and proportional similarity was 44%. The most common species at each site were uncommon at the other. The diets of 34 species were determined; 26, including the most abundant, preyed exclusively on polychaetes. As on other Indo-Pacific reefs, species partitioned prey types more finely than substrate types. Among vermivores, a different polychaete dominated the diet of each predator. Other species specialized on an enteropneust, other gastropods, and fishes. Most prey were herbivores or deposit feeders, indicating that the major trophic role of Conus speciesin the reef community is as primary carnivores. The results suggest that species are not more specialized than where fewer congeners co-occur, but rather overlap somewhat more in resource use. [ABSTRACT FROM AUTHOR]