The Growth of Seriatopora hystrix (Dana, 1846) Transplant with Differences of Fragments Size and Planting Position

Transplantation of coral reefs requires sufficient fragments but must still ensure the sustainability of coral donors. This research aimed to know the survival rate and growth rate of transplant corals with different fragment sizes and planting positions and to determine the most effective and efficient transplantation methods of the Seriatopora hystrix. The research was conducted from January to April 2016 in Serangan Island waters Denpasar Bali (1-2 m depth). The method used was a field experiment with variations of planting position (vertical, horizontal) and fragment sizes (3, 5, 7 cm). The results showed a high survival rate (98.3%) of the transplanted S. hystrix with planting position and fragment sizes variation. The variation of planting position and fragment sizes were significantly affected the length growth rate of the S. hystrix (p <0.05). The vertical planting position showed better growth compared to the horizontal planting position. The transplantation of coral with initial fragment sizes of 5 and 7 cm showed a higher growth rate than the fragment size of 3 cm. However, statistical analysis revealed no significant difference between initial fragment sizes of 5 and 7 cm. Therefore, this study demonstrated the most effective and efficient for S. hystrix transplantation showed in the vertical position with the initial fragment size of 5 cm.Key words: coral bleaching, initial fragment, tropical, zooxanthellae

Assessment of the Biological Response of the Scleractinian Coral Seriatopora Hystrix to Sunscreen Products

Every second, 0.8 litres of sunscreen enters ocean waters, which corresponds to the release of 25.000 tons per year. UV filters may present substantial threats to marine fauna and flora and have an impact similar to that of other contaminants. Coral reefs play a major role in marine biodiversity, and some publications suggest that they are threatened by the release of sunscreen into the environment, which should cause bleaching. The aim of this study was to evaluate the potential impact of sunscreen products on hard corals. Laboratory experiments in which Seriatopora hystrix coral fragments were exposed to 9 sunscreens at concentrations up to 100 mg/L for 96 hours were conducted, and the biological responses of the fragments were assessed. The examined parameters were coral bleaching and polyp retraction. The results obtained revealed that the 9 tested sunscreens had no effects on S. hystrix, with a recorded NOEC (No Observed Effect Concentration) of 100 mg/L for both tested parameters. This concentration is much higher than those of chemicals in the natural environment, which are on the order of µg/L or ng/L. Under the conditions in this experiment, the absence of toxic effects from the tested sunscreens allows us to argue the absence of potential danger on corals.

Differences in genetic diversity and divergence between brooding and broadcast spawning corals across two spatial scales in the Coral Triangle region

The Coral Triangle region contains the world’s highest marine biodiversity, however, these reefs are also the most threatened by global and local threats. A main limitation that prevents the implementation of adequate conservation measures is that connectivity and genetic structure of populations is poorly known. The aim of this study was to investigate the genetic diversity, population structure and connectivity patterns of tropical corals in Indonesia on two different spatial scales, as well as by comparing two different reproduction strategies. Genotyping was based on microsatellite markers for 316 individual Seriatopora hystrix colonies and 142 Acropora millepora colonies sampled in Pulau Seribu and Spermonde Archipelago in 2012 and 2013. Differences in allelic diversity and a strong signature of divergence associated with historical land barriers at the Sunda Shelf were found for the brooding coral Seriatopora hystrix. However, differences in diversity and divergence were not pronounced in the broadcast spawning coral Acropora millepora. Within Spermonde Archipelago, two groups were identified: (1) sites of the sheltered inner-shelf and mid-shelf, which were found to be highly interconnected and (2) mid-shelf and outer-shelf sites characterised by higher differentiation. These patterns of contemporary dispersal barriers and genetic diversity can be explained by the differences in life history of the corals, as well as by oceanographic conditions facilitating larval dispersal. The contemporary dispersal barriers found within the Spermonde Archipelago emphasise the need for incorporating connectivity data in future conservation efforts.

Proteomic Signatures of Corals from Thermodynamic Reefs

Unlike most parts of the world, coral reefs of Taiwan’s deep south have generally been spared from climate change-induced degradation. This has been linked to the oceanographically unique nature of Nanwan Bay, where intense upwelling occurs. Specifically, large-amplitude internal waves cause shifts in temperature of 6–9 °C over the course of several hours, and the resident corals not only thrive under such conditions, but they have also been shown to withstand multi-month laboratory incubations at experimentally elevated temperatures. To gain insight into the sub-cellular basis of acclimation to upwelling, proteins isolated from reef corals (Seriatopora hystrix) featured in laboratory-based reciprocal transplant studies in which corals from upwelling and non-upwelling control reefs (<20 km away) were exposed to stable or variable temperature regimes were analyzed via label-based proteomics (iTRAQ). Corals exposed to their “native” temperature conditions for seven days (1) demonstrated highest growth rates and (2) were most distinct from one another with respect to their protein signatures. The latter observation was driven by the fact that two Symbiodiniaceae lipid trafficking proteins, sec1a and sec34, were marginally up-regulated in corals exposed to their native temperature conditions. Alongside the marked degree of proteomic “site fidelity” documented, this dataset sheds light on the molecular mechanisms underlying acclimatization to thermodynamically extreme conditions in situ.

Differential Occupation of Available Coral Hosts by Coral-Dwelling Damselfish (Pomacentridae) on Australia’s Great Barrier Reef

Associations between habitat-forming, branching scleractinian corals and damselfish have critical implications for the function and trophic dynamics of coral reef ecosystems. This study quantifies how different characteristics of reef habitat, and of coral morphology, determine whether fish occupy a coral colony. In situ surveys of aggregative damselfish–coral associations were conducted at 51 different sites distributed among 22 reefs spread along >1700 km of the Great Barrier Reef, to quantify interaction frequency over a large spatial scale. The prevalence of fish–coral associations between five damselfish (Chromis viridis, Dascyllus aruanus, Dascyllus reticulatus, Pomacentrus amboinensis and Pomacentrus moluccensis) and five coral species (Acropora spathulata, Acropora intermedia, Pocillopora damicornis, Seriatopora hystrix, and Stylophora pistillata) averaged ~30% across all corals, but ranged from <1% to 93% of small branching corals occupied at each site, depending on reef exposure levels and habitat. Surprisingly, coral cover was not correlated with coral occupancy, or total biomass of damselfish. Instead, the biomass of damselfish was two-fold greater on sheltered sites compared with exposed sites. Reef habitat type strongly governed these interactions with reef slope/base (25%) and shallow sand-patch habitats (38%) hosting a majority of aggregative damselfish-branching coral associations compared to reef flat (10%), crest (16%), and wall habitats (11%). Among the focal coral species, Seriatopora hystrix hosted the highest damselfish biomass (12.45 g per occupied colony) and Acropora intermedia the least (6.87 g per occupied colony). Analyses of local coral colony traits indicated that multiple factors governed colony usage, including spacing between colonies on the benthos, colony position, and colony branching patterns. Nevertheless, the morphological and habitat characteristics that determine whether or not a colony is occupied by fish varied among coral species. These findings illuminate the realized niche of one of the most important and abundant reef fish families and provide a context for understanding how fish–coral interactions influence coral population and community level processes.

Unexpected mixed-mode transmission and moderate genetic regulation of Symbiodinium communities in a brooding coral

Determining the extent to which Symbiodinium communities in corals are inherited versus environmentally-acquired is fundamental to understanding coral resilience and to predicting coral responses to stressors like warming oceans that disrupt this critical endosymbiosis. We examined the fidelity with which Symbiodinium communities in the brooding coral Seriatopora hystrix are vertically transmitted and the extent to which communities are genetically regulated, by genotyping 60 larvae and their parents (9 maternal and 45 paternal colonies) using high throughput sequencing of the ITS-2 locus. Unexpectedly, Symbiodinium communities associated with brooded larvae were distinct from those within parent colonies, including the presence of types not detected in adults. Bayesian heritability (h2) analysis revealed that 33% of variability in larval Symbiodinium communities was genetically controlled. Results highlight flexibility in the establishment of larval communities and overturn the paradigm that symbiont transmission is exclusively vertical in brooding corals. Instead, we show that Symbiodinium transmission in S. hystrix involves a mixed-mode strategy, similar to many terrestrial invertebrate symbioses. Also, variation in the abundances of common Symbiodinium types among adult communities suggests that microhabitat differences influence the structure of in hospite Symbiodinium communities. Partial genetic regulation coupled with flexibility in the environmentally-acquired component of larval Symbiodinium communities implies that corals with vertical transmission, like S. hystrix, may be more resilient to environmental change than previously thought.