Learning from the past is not enough to survive present and future bleaching threshold temperatures.

In the past decade, the frequency of mass coral bleaching events has increased due to seawater temperature anomalies persisting for longer periods. Coral survival from temperature anomalies has been based on how each species in each location responds to stress, which is unique to individual species and may be due to the way stressful experiences accumulate through time in the form of ecological and physiological memory. A deeper understanding of ecological and physiological memory in corals is necessary to understand their survival strategies into the future. Laboratory experiments can help us simulate seawater temperatures experienced by corals in the past and compare their responses to those of the present and future. In this study, we sampled corals with different life history traits from one location perturbed by seawater temperature incursions (variable site) and from a second, relatively undisturbed location (stable site). We sampled across two seasons to observe the responses to bleaching threshold temperatures in the past (1998-29 °C), present (2018-31 °C), and future (2050-33 °C). Corals were healthy at 29 °C and 31 °C, but a fast-growing, temperature-susceptible coral species experienced high mortality at 33 °C compared to a slow-growing, temperature-resistant coral species. Moreover, corals from the variable site and during the spring season fared better under temperature stress. The results of this study provide insight into the possible role of life-history traits on coral's response to seasons and locations in terms of memory to long-term and short-term thermal anomalies and climate change.

Population genetics and demography of the coral-killing cyanobacteriosponge, Terpios hoshinota, in the Indo-West Pacific.

The first occurrence of the cyanobacteriosponge Terpios hoshinota was reported from coral reefs in Guam in 1973, but was only formally described in 1993. Since then, the invasive behavior of this encrusting, coral-killing sponge has been observed in many coral reefs in the West Pacific. From 2015, its occurrence has expanded westward to the Indian Ocean. Although many studies have investigated the morphology, ecology, and symbiotic cyanobacteria of this sponge, little is known of its population genetics and demography. In this study, a mitochondrial cytochrome oxidase I (COI) fragment and nuclear ribosomal internal transcribed spacer 2 (ITS2) were sequenced to reveal the genetic variation of T. hoshinota collected from 11 marine ecoregions throughout the Indo-West Pacific. Both of the statistical parsimony networks based on the COI and nuclear ITS2 were dominated by a common haplotype. Pairwise F ST and Isolation-by-distance by Mantel test of ITS2 showed moderate gene flow existed among most populations in the marine ecoregions of West Pacific, Coral Triangle, and Eastern Indian Ocean, but with a restricted gene flow between these regions and Maldives in the Central Indian Ocean. Demographic analyses of most T. hoshinota populations were consistent with the mutation-drift equilibrium, except for the Sulawesi Sea and Maldives, which showed bottlenecks following recent expansion. Our results suggest that while long-range dispersal might explain the capability of T. hoshinota to spread in the IWP, stable population demography might account for the long-term persistence of T. hoshinota outbreaks on local reefs.

Comparison of the bleaching susceptibility of coral species by using minimal samples of live corals.

In massive bleaching events (losing symbiotic algae from corals), more sensitive corals are bleached earlier than other corals. To perform a comparison of bleaching susceptibility within and across coral species, a simple quantitative method is required. Accordingly, we present a laboratory-based method for comparing the bleaching susceptibility of various coral species by using a standardized image analysis protocol. Coral fragments were sampled from the colonies of five species selected from Kenting, southern Taiwan, and maintained in the same aquarium tank with circulating seawater; 2 seawater temperature regimes were used (i.e., fast-heating program (FHP), with a heating rate of 1 °C per day; and slow-heating program (SHP), with a heating rate of 1 °C per 3 days). Each coral fragment was photographed periodically, and the colored images were subsequently converted to grayscale images and then digitally analyzed to determine the standardized grayscale values (G0) by comparing with that of standard color strip. The G0 of a sample at each time of photographing during bleaching was divided by the difference of G0 between the acclimating and the same but completely bleached fragment to derive the relative grayscale (RG%) at a particular stage of bleaching; this is done for each coral fragment of a colony. The smaller the RG% of a coral fragment the closer it is approaching completely bleached condition. The level of decrease in RG% within a time series of images in each heating regime was used to establish a bleaching time index (BTI). The lower the BTI, the sooner to reach a defined bleaching level (e.g., 30%), this indicates the coral is more sensitive to thermal bleaching. In the experiment, we compared the bleaching susceptibility of the five species. Based on the proposed BTI, the five species were ranked in terms of bleaching susceptibility, and the rankings were identical between the two temperature regimes; three species in Pocilloporidae had lower BTI, whereas the hydrocoral Millepora species had the highest BTI. Within each heating regime, the BTI of different species were ranked and used to indicate susceptibility. In the FHP, the three Pocilloporidae species could be divided into two groups in terms of bleaching susceptibility. FHP not only displayed a higher differentiating capability on coal bleaching susceptibility than SHP, but also had a faster completion time, thus reducing the likelihood of unforeseen complications during the tank experiments. Our color-based method is easier and less effort-intensive than methods involving the assessment of zooxanthellae densities. Moreover, it requires much fewer replicates and all samples in one large tank (e.g., 300 L) for the studies considering multiple species comparisons. This method opens opportunities for studying the effects of species types, acclimatization (e.g., seasons), and environmental factors other than temperature on coral bleaching.

Extra high superoxide dismutase in host tissue is associated with improving bleaching resistance in "thermal adapted" and Durusdinium trenchii-associating coral.

Global warming threatens reef-building corals with large-scale bleaching events; therefore, it is important to discover potential adaptive capabilities for increasing their temperature resistance before it is too late. This study presents two coral species (Platygyra verweyi and Isopora palifera) surviving on a reef having regular hot water influxes via a nearby nuclear power plant that exhibited completely different bleaching susceptibilities to thermal stress, even though both species shared several so-called "winner" characteristics (e.g., containing Durusdinium trenchii, thick tissue, etc.). During acute heating treatment, algal density did not decline in P. verweyi corals within three days of being directly transferred from 25 to 31 °C; however, the same treatment caused I. palifera to lose < 70% of its algal symbionts within 24 h. The most distinctive feature between the two coral species was an overwhelmingly higher constitutive superoxide dismutase (ca. 10-fold) and catalase (ca. 3-fold) in P. verweyi over I. palifera. Moreover, P. verweyi also contained significantly higher saturated and lower mono-unsaturated fatty acids, especially a long-chain saturated fatty acid (C22:0), than I. palifera, and was consistently associated with the symbiotic bacteria Endozoicomonas, which was not found in I. palifera. However, antibiotic treatment and inoculation tests did not support Endozoicomonas having a direct contribution to thermal resistance. This study highlights that, besides its association with a thermally tolerable algal symbiont, a high level of constitutive antioxidant enzymes in the coral host is crucial for coral survivorship in the more fluctuating and higher temperature environments.

Specificity trumps flexibility-location-based stable associations between Symbiodiniaceae genera and Platygyra verweyi (Scleractinia; Merulinidae).

This study monitored symbiont communities bi-monthly in native coral cores used in a reciprocal transplantation of the coral Platygyra verweyi over two years (2014-2016) and samples of mother colonies from three locations with variable thermal regimes; our results show that associating with multiple Symbiodiniaceae genera (Cladocopium spp. and Durusdinium spp.) is not a prerequisite for symbiont shuffling. Platygyra verweyi associates with certain Symbiodiniaceae genera based on location. Results of quantitative real-time PCR indicated small-scale temporal changes in Symbiodiniaceae genera compositions from 2014 to 2016; however, these changes were not enough to invoke shuffling or switching, despite degree heating weeks exceeding 6 °C-weeks in 2014 and 4 °C-weeks in 2015, which usually resulted in substantial coral bleaching. Microsatellite analysis of the P. verweyi host showed no genetic differences among the study locations. Our results suggest that P. verweyi undergoes long-term acclimatization and/or adaptation based on microgeographic and local environmental conditionsby altering its combinations of associated Symbiodiniaceae. Results also suggest that shuffling might not be as common a phenomenon as it has been given credit for; corals thrive through specific associations, and many corals could still be vulnerable to climate change-induced stress, despite being promiscuous or able to associate with rare and background Symbiodiniaceae genera.

The coral Platygyra verweyi exhibits local adaptation to long-term thermal stress through host-specific physiological and enzymatic response.

Climate change threatens coral survival by causing coral bleaching, which occurs when the coral's symbiotic relationship with algal symbionts (Symbiodiniaceae) breaks down. Studies on thermal adaptation focus on symbionts because they are accessible both in vitro and in hospite. However, there is little known about the physiological and biochemical response of adult corals (without Symbiodiniaceae) to thermal stress. Here we show acclimatization and/or adaptation potential of menthol-bleached aposymbiotic coral Platygyra verweyi in terms of respiration breakdown temperature (RBT) and malate dehydrogenase (MDH) enzyme activity in samples collected from two reef sites with contrasting temperature regimes: a site near a nuclear power plant outlet (NPP-OL, with long-term temperature perturbation) and Wanlitong (WLT) in southern Taiwan. Aposymbiotic P. verweyi from the NPP-OL site had a 3.1 °C higher threshold RBT than those from WLT. In addition, MDH activity in P. verweyi from NPP-OL showed higher thermal resistance than those from WLT by higher optimum temperatures and the activation energy required for inactivating the enzyme by heat. The MDH from NPP-OL also had two times higher residual activity than that from WLT after incubation at 50 °C for 1 h. The results of RBT and thermal properties of MDH in P. verweyi demonstrate potential physiological and enzymatic response to a long-term and regular thermal stress, independent of their Symbiodiniaceae partner.

Repeated and Prolonged Temperature Anomalies Negate Symbiodiniaceae Genera Shuffling in the Coral Platygyra verweyi (Scleractinia; Merulinidae).

Kuo-Wei Kao, Shashank Keshavmurthy, Cing-Hsin Tsao, Jih-Terng Wang, and Chaolun Allen Chen (2018) With climate change, global average sea surface temperatures are expected to increase by 1.0-3.7°C by the end of this century. Even a 1.0°C increase in seawater temperature from local long-term summer maxima lasting for weeks to months results in bleaching and/or mortality in reef-building corals. Studies on coral resistance mechanisms have proposed a correlation between shuffling of different Symbiodiniaceae genera (changing the dominant Symbiodiniaceae genera) and putative thermal tolerance in corals. Although it was suggested that some corals can increase their tolerance by 1.0-1.5°C through shuffling to thermally tolerant Durusdinium trenchii (formerly D1a), the effects of accumulated thermal stress due to prolonged high temperatures on the survival of corals that have shuffled have not been investigated. We show herein that prolonged exposure to high temperature (> 10.43-degree heating weeks) can drastically reduce coral survival rate even after it has shuffled to stress-tolerant Symbiodiniaceae genera. Our study suggests that there is a limit to the capacity of for shuffling, and hence is likely to lose its efficacy in the future as repeated and prolonged thermal stress events become more frequent and pronounced.

Diverse responses of Symbiodinium types to menthol and DCMU treatment.

To understand the mechanism of photosynthetic inhibition and generation of reactive oxygen species (ROS) in Symbiodinium types under stress, chemicals such as dichlorophenyl dimethylurea (DCMU) are widely used. Moreover, DCMU and recently menthol were used to generate aposymbiotic cnidarian hosts. While the effects of DCMU on Symbiodinium cells have been extensively studied, no studies have shown the mechanism behind menthol-induced coral bleaching. Moreover, no study has compared the effects of DCMU and menthol treatments on photosystem II (PSII) activity and generation of ROS in different Symbiodinium types. In this study, we utilized five freshly isolated Symbiodinium types (S. minutum (B1), S. goreaui (C1), C3, C15, and S. trenchii (D1a)) to compare the effects of DCMU and menthol treatments. Symbiodinium cells were exposed to DCMU and menthol at different concentrations for 4 h. Results showed that values of the 50% inhibitory concentration (IC50) for PSII inhibition were 0.72∼1.96 mM for menthol-treated cells compared to 29∼74 pM for DCMU-treated cells. Diverse responses of Symbiodinium types were displayed in terms of PSII tolerance to menthol (S. minutum > S. trenchii = C15 > C3 = S. goreaui), and also in the response curves. In contrast, responses were not so diverse when the different types were treated with DCMU. Three of five menthol-treated Symbiodinium types showed instant and significant ROS generation when PSII activity was inhibited, compared to no ROS being generated in DCMU-treated Symbiodinium types. Both results indicated that menthol inhibited Symbiodinium PSII activity through Symbiodinium type-dependent mechanisms, which were also distinct from those with DCMU treatment. This study further confirmed that photosynthetic functions Symbiodinium have diverse responses to stress even within the same clade.

Thalassotalea montiporae sp. nov., isolated from the encrusting pore coral Montipora aequituberculata.

A bacterial strain, designated CL-22T, was isolated from an encrusting pore coral, Montipora aequituberculata, collected off the coast of Southern Taiwan. Its taxonomic position was investigated using a polyphasic approach. Cells of strain CL-22T were Gram-stain-negative, aerobic, motile by means of a single polar flagellum, rod-shaped and formed yellow colonies. Optimal growth occurred at 30 °C, pH 6.5-7 and in 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree, based on 16S rRNA gene sequences, showed that strain CL-22T fell into the clade comprising the type strains of species of the genus Thalassotalea. Strain CL-22T exhibited 16S rRNA gene sequence similarity values of 94.7-97.1 % to the type strains of species of the genus Thalassotalea. The major fatty acids (>10 %) of strain CL-22T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The predominant isoprenoid quinone was Q-8. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA G+C content of strain CL-22T was 41.2 mol%. The differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain CL-22T should be classified as a novel species of the genus Thalassotalea; the name Thalassotalea montiporae sp. nov. is proposed. The type strain is CL-22T (=LMG 24827T=BCRC 17940T).

Physiological outperformance at the morphologically-transformed edge of the cyanobacteriosponge Terpios hoshinota (Suberitidae: Hadromerida) when confronting opponent corals.

Terpios hoshinota, an encrusting cyanosponge, is known as a strong substrate competitor of reef-building corals that kills encountered coral by overgrowth. Terpios outbreaks cause significant declines in living coral cover in Indo-Pacific coral reefs, with the damage usually lasting for decades. Recent studies show that there are morphological transformations at a sponge's growth front when confronting corals. Whether these morphological transformations at coral contacts are involved with physiological outperformance (e.g., higher metabolic activity or nutritional status) over other portions of Terpios remains equivocal. In this study, we compared the indicators of photosynthetic capability and nitrogen status of a sponge-cyanobacteria association at proximal, middle, and distal portions of opponent corals. Terpios tissues in contact with corals displayed significant increases in photosynthetic oxygen production (ca. 61%), the δ13C value (ca. 4%), free proteinogenic amino acid content (ca. 85%), and Gln/Glu ratio (ca. 115%) compared to middle and distal parts of the sponge. In contrast, the maximum quantum yield (Fv/Fm), which is the indicator usually used to represent the integrity of photosystem II, of cyanobacteria photosynthesis was low (0.256~0.319) and showed an inverse trend of higher values in the distal portion of the sponge that might be due to high and variable levels of cyanobacterial phycocyanin. The inconsistent results between photosynthetic oxygen production and Fv/Fm values indicated that maximum quantum yields might not be a suitable indicator to represent the photosynthetic function of the Terpios-cyanobacteria association. Our data conclusively suggest that Terpios hoshinota competes with opponent corals not only by the morphological transformation of the sponge-cyanobacteria association but also by physiological outperformance in accumulating resources for the battle.

Can resistant coral-Symbiodinium associations enable coral communities to survive climate change? A study of a site exposed to long-term hot water input.

Climate change has led to a decline in the health of corals and coral reefs around the world. Studies have shown that, while some corals can cope with natural and anthropogenic stressors either through resistance mechanisms of coral hosts or through sustainable relationships with Symbiodinium clades or types, many coral species cannot. Here, we show that the corals present in a reef in southern Taiwan, and exposed to long-term elevated seawater temperatures due to the presence of a nuclear power plant outlet (NPP OL), are unique in terms of species and associated Symbiodinium types. At shallow depths (<3 m), eleven coral genera elsewhere in Kenting predominantly found with Symbiodinium types C1 and C3 (stress sensitive) were instead hosting Symbiodinium type D1a (stress tolerant) or a mixture of Symbiodinium type C1/C3/C21a/C15 and Symbiodinium type D1a. Of the 16 coral genera that dominate the local reefs, two that are apparently unable to associate with Symbiodinium type D1a are not present at NPP OL at depths of <3 m. Two other genera present at NPP OL and other locations host a specific type of Symbiodinium type C15. These data imply that coral assemblages may have the capacity to maintain their presence at the generic level against long-term disturbances such as elevated seawater temperatures by acclimatization through successful association with a stress-tolerant Symbiodinium over time. However, at the community level it comes at the cost of some coral genera being lost, suggesting that species unable to associate with a stress-tolerant Symbiodinium are likely to become extinct locally and unfavorable shifts in coral communities are likely to occur under the impact of climate change.

A continuous, real-time water quality monitoring system for the coral reef ecosystems of Nanwan Bay, Southern Taiwan.

The coral reef ecosystems of Nanwan Bay, Southern Taiwan are undergoing degradation due to anthropogenic impacts, and as such have resulted in a decline in coral cover. As a first step in preventing the continual degradation of these coral reef environments, it is important to understand how changes in water quality affect these ecosystems on a fine-tuned timescale. To this end, a real-time water quality monitoring system was implemented in Nanwan Bay in 2010. We found that natural events, such as cold water intrusion due to upwelling, tended to elicit temporal shifts in coral spawning between 2010 and 2011. In addition, Degree Heating Weeks (DHWs), a commonly utilized predictor of coral bleaching, were 0.92 and 0.59 in summer 2010 and 2011, respectively. Though this quantity of DHW was below the presumed stress-inducing value for these reefs, a rise in DHWs in the future may stress the resident corals.

Corallomonas stylophorae gen. nov., sp. nov., a halophilic bacterium isolated from the reef-building coral Stylophora pistillata.

A heterotrophic marine bacterium, designated strain KTSW-6(T), was isolated from the reef-building coral Stylophora pistillata in Kenting, Taiwan. Cells of strain KTSW-6(T) were Gram-stain-negative, facultatively anaerobic, halophilic, non-motile rods surrounded by a thick glycocalyx-like coat and forming creamy white colonies. Growth occurred at 15-37 °C (optimum, 25-30 °C), at pH 7.0-9.0 (optimum, pH 7.5-8.0) and with 0.5-7 % NaCl (optimum, 3-4 %). Polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an uncharacterized aminophospholipid and three uncharacterized phospholipids (PL1-PL3). The respiratory quinones of strain KTSW-6(T) were Q-8 (62 %) and Q-7 (38 %). Major cellular fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c, 29.6 %), C18 : 1ω7c (27.6 %) and C16 : 0 (19.5 %). The major cellular hydroxy fatty acid was C10 : 0 3-OH. The DNA G+C content of strain KTSW-6(T) was 48.6 mol%. 16S rRNA gene sequence analysis indicated that strain KTSW-6(T) belongs to the family Oceanospirillaceae of the order Oceanospirillales, class Gammaproteobacteria. Strain KTSW-6(T) shared 92.7 % 16S rRNA gene sequence similarity with Neptuniibacter caesariensis MED92(T) and 92.0 % with Neptunomonas naphthovorans NAG-2N-126(T). On the basis of the genotypic and phenotypic data, strain KTSW-6(T) represents a novel species of a new genus of the Oceanospirillaceae, for which the name Corallomonas stylophorae gen. nov., sp. nov. is proposed. The type strain of Corallomonas stylophorae is KTSW-6(T) ( = BCRC 80176(T) = LMG 25553(T)).

Physiological and biochemical performances of menthol-induced aposymbiotic corals.

The unique mutualism between corals and their photosynthetic zooxanthellae (Symbiodinium spp.) is the driving force behind functional assemblages of coral reefs. However, the respective roles of hosts and Symbiodinium in this endosymbiotic association, particularly in response to environmental challenges (e.g., high sea surface temperatures), remain unsettled. One of the key obstacles is to produce and maintain aposymbiotic coral hosts for experimental purposes. In this study, a simple and gentle protocol to generate aposymbiotic coral hosts (Isopora palifera and Stylophora pistillata) was developed using repeated incubation in menthol/artificial seawater (ASW) medium under light and in ASW in darkness, which depleted more than 99% of Symbiodinium from the host within 4∼8 days. As indicated by the respiration rate, energy metabolism (by malate dehydrogenase activity), and nitrogen metabolism (by glutamate dehydrogenase activity and profiles of free amino acids), the physiological and biochemical performances of the menthol-induced aposymbiotic corals were comparable to their symbiotic counterparts without nutrient supplementation (e.g., for Stylophora) or with a nutrient supplement containing glycerol, vitamins, and a host mimic of free amino acid mixture (e.g., for Isopora). Differences in biochemical responses to menthol-induced bleaching between Stylophora and Isopora were attributed to the former digesting Symbiodinium rather than expelling the algae live as found in the latter species. Our studies showed that menthol could successfully bleach corals and provided aposymbiotic corals for further exploration of coral-alga symbioses.

Recurrent disturbances and the degradation of hard coral communities in Taiwan.

Recurrent disturbances can have a critical effect on the structure and function of coral reef communities. In this study, long-term changes were examined in the hard coral community at Wanlitung, in southern Taiwan, between 1985 and 2010. In this 26 year interval, the reef has experienced repeated disturbances that include six typhoons and two coral-bleaching events. The frequency of disturbance has meant that species susceptible to disturbance, such as those in the genus Acropora and Montipora have almost disappeared from the reef. Indeed, almost all hard coral species have declined in abundance, with the result that total hard coral cover in 2010 (17.7%) was less than half what it was in 1985 (47.5%). In addition, macro-algal cover has increased from 11.3% in 2003 to 28.5% in 2010. The frequency of disturbance combined with possible chronic influence of a growing human population mean that a diverse reef assemblage is unlikely to persist on this reef into the future.

Symbiont communities and host genetic structure of the brain coral Platygyra verweyi, at the outlet of a nuclear power plant and adjacent areas.

In the context of rising seawater temperatures associated with climate change, the issue of whether coral holobionts deal with this challenge by shuffling their associations with stress- and/or heat-tolerant Symbiodinium, by generating heat-resistant host genotypes, or both is important for coral survival. In this study, the composition of communities of the endosymbiont Symbiodinium and the population genetics of the coral host Platygyra verweyi were examined in a reef impacted by hot-water discharged from the outlet of a nuclear power plant in operation in Kenting, Southern Taiwan since 1984. The water at this site is 2.0-3.0 °C warmer than adjacent reefs in summer, which have an average seawater temperature of 29.0 °C. The data were compared with those for the same species at other sites within 12 km of the outlet site. Platygyra verwyei was associated with one or both of Symbiodinium types C3 (heat sensitive) and D1a (heat tolerant) at all sites with the latter being the dominant at the nuclear power plant outlet. The proportion of C3 in populations increased gradually with increasing distance from the hot-water discharge. Genetic analysis of the Platygyra verweyi host using mitochondrial and nuclear markers showed no genetic differentiation among sites. Changes in the composition of Symbiodinium types associated with P. verweyi among closely located sites in Kenting suggested that this coral might have acclimatized to the constant thermal stress by selective association with heat-tolerant Symbiodinium types, whereas the role of the host in adaptation was inconclusive.

Impacts of human activities on coral reef ecosystems of southern Taiwan: a long-term study.

In July 2001, the National Museum of Marine Biology and Aquarium, co-sponsored by the Kenting National Park Headquarters and Taiwan's National Science Council, launched a Long-Term Ecological Research (LTER) program to monitor anthropogenic impacts on the ecosystems of southern Taiwan, specifically the coral reefs of Kenting National Park (KNP), which are facing an increasing amount of anthropogenic pressure. We found that the seawater of the reef flats along Nanwan Bay, Taiwan's southernmost embayment, was polluted by sewage discharge at certain monitoring stations. Furthermore, the consequently higher nutrient and suspended sediment levels had led to algal blooms and sediment smothering of shallow water corals at some sampling sites. Finally, our results show that, in addition to this influx of anthropogenically-derived sewage, increasing tourist numbers are correlated with decreasing shallow water coral cover, highlighting the urgency of a more proactive management plan for KNP's coral reefs.

Idiomarina aquimaris sp. nov., isolated from the reef-building coral Isopora palifera.

A bacterial strain designated SW15(T) was isolated from a sample of the reef-building coral Isopora palifera, collected in southern Taiwan. The novel strain was characterized using a polyphasic taxonomic approach. Cells of strain SW15(T) were Gram-negative, aerobic, light yellow, rod-shaped and motile by means of a single polar flagellum. In phylogenetic analyses based on 16S rRNA gene sequences, strain SW15(T) appeared to belong to the genus Idiomarina in the class Gammaproteobacteria and to be most closely related to Idiomarina homiensis PO-M2(T) (97.6% sequence similarity). Strain SW15(T) exhibited optimal growth between 20 and 30 °C, with NaCl between 3% and 4% (w/v) and at a pH value between 7 and 8. Predominant cellular fatty acids were iso-C(15:0) (31.1%), iso-C(17:0) (15.4%), iso-C(17:1)ω9c (10.0%) and C(16:0) (8.8%). The major respiratory quinone was ubiquinone Q-8. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylserine, an uncharacterized aminolipid and several uncharacterized phospholipids. The DNA G+C content was 51.1 mol%. The level of DNA-DNA relatedness between strain SW15(T) and Idiomarina homiensis PO-M2(T) was 42.6-56.5%. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of the novel strain from established species of the genus Idiomarina. Based on the genotypic, phenotypic and chemotaxonomic data, strain SW15(T) represents a novel species in the genus Idiomarina, for which the name Idiomarina aquimaris sp. nov. is proposed, with SW15(T) (=LMG 25374(T)=BCRC 80083(T)) as the type strain.

Oceanicaulis stylophorae sp. nov., isolated from the reef-building coral Stylophora pistillata.

A bacterial strain designated GISW-4(T) was isolated from the reef-building coral Stylophora pistillata, collected from seawater off the coast of southern Taiwan, and was characterized in this taxonomic study using a polyphasic approach. Strain GISW-4(T) was Gram-stain-negative, aerobic, beige, rod-shaped, and dimorphic, either non-motile with stalks (or prosthecae), or non-stalked and motile by means of a single polar flagellum. 16S rRNA gene sequence studies showed that the novel strain clustered with Oceanicaulis alexandrii C116-18(T) (98.9 % 16S rRNA gene sequence similarity). Strain GISW-4(T) exhibited optimal growth at 35-40 °C, 1-2 % (w/v) NaCl and at pH 7-9. The predominant cellular fatty acids (>10 %) were C(18 : 0), C(18 : 1)ω7c and C(18 : 1)ω7c 11-methyl. The predominant polar lipids were phosphatidylglycerol, sulfoquinovosyl diacylglycerol and two unknown phospholipids (PL1-2). The major respiratory quinones were ubiquinone Q-10 and Q-9, and the DNA G+C content was 61.6 mol%. The results of physiological and biochemical tests allowed clear phenotypic differentiation of strain GISW-4(T) from the type strain of O. alexandrii. It is evident from the genotypic, phenotypic and chemotaxonomic data that the isolate should be classified as a novel species of the genus Oceanicaulis. The name proposed for this taxon is Oceanicaulis stylophorae sp. nov., with the type strain GISW-4(T) (= LMG 25723(T) = BCRC 80207(T)).

Roseivivax isoporae sp. nov., isolated from a reef-building coral, and emended description of the genus Roseivivax.

A bacterial strain, isolated from a sample of reef-building coral (Isopora palifera) collected off the coast of southern Taiwan, was characterized using a polyphasic taxonomic approach. The strain, designated sw-2(T), was Gram-staining-negative, aerobic, rod-shaped and motile, with subpolar flagella, and formed greyish pink colonies. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain sw-2(T) was most closely related to Roseivivax halodurans Och 239(T) (97.4 % sequence similarity) and Roseivivax halotolerans Och 210(T) (96.4 %). The novel strain did not require NaCl for growth and exhibited optimal growth at 35-40 °C, at pH 7.5-8.0 and with 3-7 % (w/v) NaCl. It produced bacteriochlorophyll a under aerobic conditions. Summed feature 8 (C(18:1)ω7c and/or C(18:1)ω6c; 63.7 %) predominated in the cellular fatty acid profile. The novel strain's major respiratory quinone was ubiquinone Q-10 and its genomic DNA G+C content was 68.8 mol%. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, phosphatidyldimethylethanolamine, sulfo-quinovosyl diacylglycerol and three uncharacterized phospholipids. The level of DNA-DNA relatedness between strain sw-2(T) and Roseivivax halodurans Och 239(T) was only 15.0 %. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of the novel strain from all established species of the genus Roseivivax. Based on the genotypic, phenotypic and chemotaxonomic data, strain sw-2(T) represents a novel species in the genus Roseivivax, for which the name Roseivivax isoporae sp. nov. is proposed. The type strain is sw-2(T) ( = LMG 25204(T) = BCRC 17966(T)).