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Living colonies of the cold-water scleractinian coral Lophelia pertusa and other typically deep-water organisms were discovered in unusually shallow depths (180-250 m) off northeastern Florida. Observations of L. pertusa on rocky substrata and coral-built mounds represent the shallowest records of large colonies of this coral in the western Atlantic Ocean. Bioherms up to 30 m tall, extensive areas of eroded L. pertusa rubble, and a well-developed cold-water community indicated that these sites are long-term features, rather than short-term opportunistic responses to temporary shifts in environmental conditions. Species that are commonly observed on deeper reefs off the southeastern USA were abundant at the shallow sites. The most abundant fishes on reef habitats were Helicolenus dactylopterus, Laemonema barbatulum, Dysommina rugosa, and Anthias spp. In addition to L. pertusa, the most common macroinvertebrates on hard substrata were Eumunida picta, Chaceon fenneri, octocorals, cup corals, and glass sponges. Bottom and near-bottom temperatures (7-10 °C) and nutrient concentrations at the shallow sites were similar to those normally encountered at 500-600 m in this region. The shallow reef sites occur in an area known for frequent Gulf Stream-driven upwelling of deep, nutrient-rich water. However, the upwelling must be persistent or permanent in order to maintain deep-sea communities at such shallow depths. Based on these data, this area is under final review by the US Department of Commerce for inclusion in one of the regional Coral Habitat Areas of Particular Concern. [ABSTRACT FROM AUTHOR]

The red crab, Gecarcoidea natalis, is endemic to Christmas Island in the Indian Ocean and largely responsible for shaping the unique ecosystem found throughout the island's rainforests. However, the introduction and establishment of supercolonies of the highly invasive yellow crazy ant, Anoplolepis gracilipes, has decimated red crab numbers over the last several decades. This poses a significant risk to the future conservation of G. natalis and consequently threatens the integrity of the unique island ecosystem. Here we undertook a population genetic analysis of G. natalis using a combination of 11 microsatellite markers and sequencing of the mitochondrial cytochrome oxidase subunit I gene from samples collected on Christmas Island as well as a single location from North Keeling Island (located approximately 900 km west of Christmas Island). The genetic results indicate that G. natalis is a single panmictic population on Christmas Island, with no spatial genetic structure or restricted gene flow apparent between sampled locations. Further, G. natalis from North Keeling Island are not genetically distinct and are recent immigrants from Christmas Island. The effective population size of G. natalis has likely remained large and stable on Christmas Island throughout its evolutionary history with relatively moderate to high levels of genetic diversity in microsatellite loci and mitochondrial haplotypes assessed in this study. For management purposes G. natalis can be considered a single panmictic population, which should simplify conservation efforts for the genetic management of this iconic island species. [ABSTRACT FROM AUTHOR]