Ocean warming increases the incidence of coral bleaching, which reduces or eliminates the nutrition corals receive from their algal symbionts, often resulting in widespread mortality. In contrast to extensive knowledge on the thermal tolerance of coral-associated symbionts, the role of the coral host in bleaching patterns across species is poorly understood. Here, we applied a Bayesian analysis of carbon and nitrogen stable isotope data to determine the trophic niche overlap between corals and their symbionts and propose benchmark values that define autotrophy, heterotrophy, and mixotrophy. The amount of overlap between coral and symbiont niche was negatively correlated with polyp size and bleaching resistance. Our results indicated that as oceans warm, autotrophic corals lose their competitive advantage and thus are the first to disappear from coral reefs.

A new syndrome in sea fans Gorgonia ventalina consisting of multifocal purple spots (MFPS) has been observed in the Caribbean Sea. Surveys of MFPS on sea fans were conducted from 2006 to 2010 at a shallow and deep site in La Parguera, Puerto Rico (PR). At the shallow site, MFPS increased between 2006 and 2010 (site average ranged from 8 to 23%), with differences found at depths over time using an analysis of covariance (ANCOVA, p < 0.0001). As a potential causative agent we examined a Labyrinthulomycota-like ovoid parasite that was observed to be abundant in MFPS lesions in light micrographs. Labyrinhylomycetes were successfully isolated, cultured and characterized in sea fans from Florida and PR. Sequence information obtained from the small subunit (SSU) rRNA gene indicated that Labyrinthulomycetes in most sea fans (healthy and MFPS sea fans from Florida; MFPS from PR) and the cultured microorganism are in the genus Aplanochytrium, although some healthy sea fans from PR contained members of the genus Thraustochytrium. Both genera fall within the family Thraustochytriidae. Histology confirmed ob servations of thraustochytrids within apparently healthy and MFPS sea fans from PR, and specific staining indicated a host melanization response only in colonies containing Labyrinthulomycetes or fungal infections. Growth trials indicate that the temperature-growth optima for the cultured microorganism is ~30°C. In inoculation experiments, the cultured Aplanochytrium did not induce purple spots, and histology revealed that many of the apparently healthy recipients contained Labyrinthulomycetes prior to inoculation. Taken together, these results indicate that the Labyrinthulomycetes associated with sea fans is likely an opportunistic pathogen. Further studies are needed to understand the pathogenesis of this microorganism in sea fans and its relationship with MFPS.KEY WORDS: Labyrinthulomycota · Caribbean sea fan · Gorgonia ventalina · Multi-focal purple spots · MFPS Resale or republication not permitted without written consent of the publisherDis Aquat Org 101: [1][2][3][4][5][6][7][8][9][10][11][12] 2012 increase in the number of purple sclerites and is a generalized response to invading pathogens or other biotic agents (Petes et al. 2003, Alker et al. 2004, Smith & Weil 2004. Necrotic lesions, surrounded by purple halos in G. ventalina, have been described as aspergillosis (Smith et al. 1996, Nagelkerken et al. 1997, Kim & Harvell 2001. The terrestrial fungus Aspergillus sy dowii was isolated from fans with these signs and Koch's postulates fulfilled in controlled laboratory experiments (Smith et al. 1996, Geiser et al. 1998). More recently, culture-dependent sampling showed that fungal species other than A. sydowii can be associated with lesions (ToledoHernández et al. 2008). During field surveys in Mexico, Florida, and Puerto Rico, a new type of lesion was identified (Weil & Hooten 2009, Weil & Rogers 2011 our Fig. 1) that is characterized by small (1 to 3 mm in diameter), circular to oblong multi-focal...

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We describe a novel alcyoniid species of stoloniferous octocoral found off the coast of North Carolina, USA. Colonies have an encrusting morphology with pale to bright blue monomorphic polyps connected by spongy, sclerite-dense stolons that often form mats. Sclerites are colourless and sparsely tubercled. Sclerites of the stolons are predominantly spindles and rods with rare irregular fused forms, butterflies, and crosses. Polyps have a crown and points formation that consists of rods and spindles that can be curved or irregularly branched. Tentacles contain short flattened rods and rare crosses. Both the mitochondria-encoded COI-5P and mtMutS were sequenced and BLAST searches revealed no close homology with any previously sequenced species. Phylogenetic analyses of the sequence data suggested a closest relationship with species of Alcyonium Linnaeus, 1758 (Alcyoniidae) and Gersemia Marenzeller, 1877 (Nephtheidae) and supported the recognition of a new genus. This species was not previously reported in the Carolinas region despite extensive historical sampling and a recently published key to octocorals of the South Atlantic Bight. Reports and photographs from local divers suggest that this species may have been introduced in North Carolina waters ~2002–04, where it has been found on both shipwrecks and hard bottom ledges, at 13–34m depth.

Phestilla subodiosussp. nov. (Nudibranchia: Trinchesiidae) is a novel species that feeds on corals in the genus Montipora (Scleractinia: Acroporidae) which are economically important in the aquarium industry. Nuclear-encoded H3, 28SC1-C2, and mitochondrial-encoded COI and 16S markers were sequenced. Phylogenetic analysis, Automatic Barcode Gap Discovery (ABGD), morphological data, and feeding specialization all support the designation of Phestilla subodiosussp. nov. as a distinct species. Although new to science, Phestilla subodiosussp. nov. had been extensively reported by aquarium hobbyists as a prolific pest over the past two decades. The species fell into a well-studied genus, which could facilitate research into its control in reef aquaria. Our phylogenetic analysis also revealed Tenellia chaetopterana formed a well-supported clade with Phestilla. Based upon a literature review, its original morphological description, and our phylogenetic hypothesis, we reclassified this species as Phestilla chaetopteranacomb. nov.

Recently, we published a novel method used to assess the trophic niches of different coral species and demonstrated that their nutrition varied considerably, with some species highly dependent on their photosynthetic algal symbionts and others able to feed on plankton to meet energetic requirements. Adjustments to the use of this tool are necessary when it is applied to other scientific questions and symbiotic organisms. We respond to a comment highlighting a risk of bias in the methods, discuss suggested adjustments, and propose further refinements to improve method robustness.