Project description:Outbreaks of the coral-killing sponge Terpios hoshinota Rützler and Muzik, 1993 have become a threat to corals and result in coral reef deterioration. This species has an increasing distribution in the Indo-Pacific Ocean and thrives in patches on some reefs in Okinawa, Japan. However, the dispersal process and mechanisms involved remain unknown. We observed the self and non-self recognition capabilities of T. hoshinota by performing contact assays in aquarium and in the field. In the contact assays (indirect and direct contact), allogeneic sets did not fuse and showed a rejection reaction as they formed boundaries (approx. 0.2 mm width) between their tissues. Although the initial reaction between individuals involved adhesion in allogeneic sets, the two individuals remained distant from each other. Histological observations showed that soft tissues (such as collagen) were not present in the boundary zones. These boundaries were maintained for more than 2 weeks. Boundary formations were also confirmed at three field sites in Okinawa, Japan. Our results suggest that T. hoshinota can distinguish self and non-self individuals. Contact assays are a useful method for evaluating the spatial distribution and local population structures of T. hoshinota in coral reefs.
Project description:Terpios hoshinota is a thin encrusting sponge that overgrows live scleractinian corals and it is linked to coral loss in many reefs. However, our knowledge of the species associated with this sponge species is poor. During a periodical survey of T. hoshinota in 2020, we found tiny snails crawling on the sponge in the subtropical waters around Okinawa Island, Japan. We observed egg capsules inside the sponge tissue and veliger larvae released from the egg capsules. Molecular analyses of both the snails and veliger larvae (cytochrome oxidase I, COI) showed that they were identical and belonged to Joculator sp. (family Cerithiopsidae). There was no direct observation of predation on the sponge by this snail; however, to the best of our knowledge, this is the first report on a close association between a snail and the sponge T. hoshinota.
Project description:The cyanobacteriosponge Terpios hoshinota occurs on tropical reefs throughout the Indo-Pacific. The species encrusts live coral, and other benthos, and is considered a pest species that can threaten the health and productivity of locally native benthic communities on coral reefs. Here we assemble a complete mitochondrial genome to aid further research into the range expansion of this species. The circular genome was 20,504 bp in length and encoded 14 protein-coding genes, two ribosomal RNA (rRNA) genes, and 25 transfer RNA (tRNA) genes. A phylogenetic analysis based on the concatenated sequences of 14 protein-coding genes of 12 members of the subclass Heteroscleromorpha including the newly sequenced T. hoshinota, suggests further taxonomic revisions within the order Suberitida may be warranted.
Project description:The coral-killing sponge, Terpios hoshinota is a global invasive species that has conquered coral patches within a short span of time, which has led to a significant decline in living coral cover at various geographical locations. In this study, we surveyed the linear progression and impact of the Terpios invasion on live coral patches along Palk Bay, Indian Ocean, from August 2013 to August 2015. The field inventory revealed an extensive fatality rate of 76% as a result of Terpios outbreak. Experimental findings showed that symbiotic cyanobacteria act as a nutritional factory for the aggressive growth of Terpios. Shading hypothetically impairs the nutritional symbiont of the invasive species: the effect of sunlight on cyanobacterial biomass and its influence on Terpios progression over live coral patches was tested through in situ shading experiments. This study showed that artificial shading with cotton fabric could effectively mitigate sponge growth on live coral without affecting coral homeostasis.
Project description:Masashi Yomogida, Masaru Mizuyama, Toshiki Kubomura, and James Davis Reimer (2017) Terpios hoshinota is cyanobacteriosponge that can cause serious damage to coral reef ecosystems by undergoing rapid breakouts in which it smothers and encrusts hard substrates, killing living sessile benthic organisms and reducing biodiversity of the a ected area. The reasons for these outbreaks are still unclear, as are long-term prognoses of affected reefs. Some reports have suggested outbreaks may not be permanent, but very little long-term monitoring information exists. In this study, we report on a T. hoshinota outbreak (~24% coverage) at Yakomo, Okinoerabu-jima Island, Kagoshima, Japan between 2010 to 2014. In this period, the existing outbreak was seen to almost completely disappear (~0%) after unusually severe Typhoon Songda passed by in early June 2011. After this, macroalgae and a cyanobacterial bloom became the dominant benthos, but by September 2014, T. hoshinota coverage had recovered to approximately half of its pre-typhoon coverage, suggesting the conditions that had caused the outbreak still persisted at Yakomo. While the conditions promoting T. hoshinota growth at this site remain uncertain, it appears that subtropical typhoons could play an important role in the dynamics of T. hoshinota outbreaks and disappearances.