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Coral colonies regularly suffer tissue damage from natural and anthropogenic sources. The resultant wounds can decrease colony fitness and act as sources of infection or algal overgrowth. By systematically breaking branches on 54 Pocillopora meandrina colonies and following in situ tissue regeneration (April-August 2017), variation in the wound recovery process was investigated within colonies, among colonies, and across four sites on O'ahu, Hawai'i. Ninety-five percent of all wounds healed, with an average healing time of 42 days. Average healing time was not different between initial and subsequent wounds. The relative importance of intrinsic factors, extrinsic factors, and disturbance history for the wound repair process was examined. Previous colony stressors, i.e., percent live coral tissue and bleaching history, were not correlated with wound healing time. These results indicate that wound repair is a priority for P. meandrina. Colony size and depth were significantly correlated with wound healing time: larger colonies healed 14 days faster than smaller colonies, and deeper colonies healed 25 days slower than shallower colonies. These findings support the hypothesis that larger colonies have more energy available for tissue regeneration. The observation of longer healing times for deeper colonies is likely driven by extrinsic factors that vary with depth, including temperature, wave energy, and irradiance. Overall, we show that wound healing in P. meandrina is physiologically resilient to previous stressors, but is affected by both colony size and depth. Understanding drivers of variation in regenerative processes for corals is critical for predicting coral population recovery after disturbances., Author(s): Chelsie W. W. Counsell [sup.1], Erika C. Johnston [sup.1], Tayler L. Sale [sup.2] Author Affiliations: (1) 0000 0001 2188 0957, grid.410445.0, School of Ocean and Earth Science Technology, Hawai'i [...]

Significant warming and acidification of the oceans is projected to occur by the end of the century. C[O.sub.2] vents, areas of upwelling and downwelling, and potential leaks from carbon capture and storage facilities may also cause localised environmental changes, enhancing or depressing the effect of global climate change. Coldwater coral ecosystems are threatened by future changes in carbonate chemistry, yet our knowledge of the response of these corals to high temperature and high C[O.sub.2] conditions is limited. Dimethylsulphoniopropionate (DMSP), and its breakdown product dimethylsulphide (DMS), are putative antioxidants that may be accumulated by invertebrates via their food or symbionts, although recent research suggests that some invertebrates may also be able to synthesise DMSP. This study provides the first information on the impact of high temperature (12°C) and high C[O.sub.2] (817 ppm) on intracellular DMSP in the cold-water coral Lophelia pertusa from the Mingulay reef Complex, Scotland (56° 49'N, 07° 23'W), where in situ environmental conditions are meditated by tidally induced downwellings. An increase in intracellular DMSP under high C[O.sub.2] conditions was observed, whilst water column particulate DMS + DMSP was reduced. In both high temperature treatments, intracellular DMSP was similar to the control treatment, whilst dissolved DMSP + DMS was not significantly different between any of the treatments. These results suggest that L. pertusa accumulates DMSP from the surrounding water column; uptake may be up-regulated under high C[O.sub.2] conditions, but mediated by high temperature. These results provide new insight into the biotic control of deep-sea biogeochemistry and may impact our understanding of the global sulphur cycle, and the survival of cold-water corals under projected global change., Introduction Since the industrial revolution, atmospheric C[O.sub.2] emissions have continued to rise as a direct result of industrial and agricultural growth, from pre-industrial levels of 280 parts per million (IPCC [...]

Population outbreaks of corallivorous Drupella gastropods have caused mass coral mortality, but there is insufficient information on their feeding behaviour to develop useful reef management strategies. This study examined the feeding rates of two Drupella species, D. rugosa (Born 1778) and D. margariticola (Broderip 1833), and investigated whether the presence of the coral guard crab, Trapezia cymodoce (Herbst 1801), could help to reduce corallivory on Pocillopora acuta (Lamarck 1816). Our mesocosm study showed that the feeding rate of D. rugosa (1.81 ± 0.95 cm.sup.2 coral tissue/day) was significantly higher than that of D. margariticola (0.51 ± 0.75 cm.sup.2 coral tissue/day). The presence of T. cymodoce reduced the feeding rate of D. rugosa by 22.9%; this was lower than that by other Trapezia congenerics. Trapezia cymodoce also did not display much aggressive behaviour towards D. rugosa. This study has highlighted that D. rugosa can cause considerable damage to corals and defence by T. cymodoce alone is unlikely to be effective against Drupella corallivory. Early detection of Drupella outbreaks and the subsequent development of mitigation measures remain of paramount importance in reducing the impact of corallivory on coral reefs., Author(s): Astri Noorbaini Samsuri [sup.1] , Yuichi Preslie Kikuzawa [sup.2] , Daisuke Taira [sup.2] , Shu Qin Sam [sup.2] , Wan Ting Sim [sup.2] , Chin Soon Lionel Ng [sup.2] [...]

The temporal dynamics of the invertebrate immune response often determines an organism's success in responding to physiological stress, physical damage, and pathogens. To date, most immune challenge studies have been conducted under highly controlled laboratory conditions, with few attempts to study immune function in the wild. In this study, we characterized the temporal dynamics of the Caribbean sea fan, Gorgonia ventalina, cellular immune response [granular amoebocyte aggregation and prophenoloxidase (PPO) activation] to allogenic grafts in the laboratory and field using a clonally replicated design. Amoebocyte reaction time differed markedly between the lab (% amoebocyte surface area in tissue sections peaked at 2 days) and field (peak at 6 days). PPO activity decreased between 0 and 6 days after grafting in both ungrafted and grafted tissue, suggesting PPO is decoupled from other cellular components. The reaction norms of the fold induction in % amoebocyte area between disease-grafted and healthy-grafted tissue of each colony across time indicate high intercolony plasticity in cellular immune response. The plasticity between colonies was also evident in the magnitude of cellular immune response, ranging from a 0.88- to 1.60-fold increase in amoebocyte area between initial and 6 days for the disease-grafted tissue. With the demonstration of highly dynamic cnidarian cellular immune responses, our study expands understanding of the evolutionary ecology of metazoan immune defense mechanisms., Introduction The invertebrate immune system is distinct from that of vertebrates in lacking adaptive immunity and relying solely on a diverse repertoire of innate immune defenses to recognize foreign materials, [...]