Seriatopora Caliendrum Research Articles

Evidence that high pCO2 affects protein metabolism in tropical reef corals.

Early life stages of the coral Seriatopora caliendrum were used to test the hypothesis that the depression of dark respiration in coral recruits by high pCO2 is caused by perturbed protein metabolism. First, the contribution of protein anabolism to respiratory costs under high pCO2 was evaluated by measuring the aerobic respiration of S. caliendrum recruits with and without the protein synthesis inhibitor emetine following 1 to 4 days at 45 Pa versus 77 Pa pCO2. Second, protein catabolism under high pCO2 was evaluated by measuring the flux of ammonium (NH4 (+)) from juvenile colonies of S. caliendrum incubated in darkness at 47 Pa and 90 Pa pCO2. Two days after settlement, respiration of recruits was affected by an interaction between emetine and pCO2, with emetine reducing respiration 63% at 45 Pa pCO2 and 27% at 77 Pa pCO2. The interaction disappeared 5 days after settlement, when respiration was reduced 27% by emetine under both pCO2 conditions. These findings suggest that protein anabolism accounted for a large proportion of metabolic costs in coral recruits and was affected by high pCO2, with consequences detected in aerobic respiration. Juvenile S. caliendrum showed net uptake of NH4 (+) at 45 Pa pCO2 but net release of NH4 (+) at 90 Pa pCO2, indicating that protein catabolism, NH4 (+) recycling, or both were affected by high pCO2. Together, these results are consistent with the hypothesis that high pCO2 affects protein metabolism in corals.

Cellular membrane accommodation of copper-induced oxidative conditions in the coral Seriatopora caliendrum

Oxidative stress has been associated with copper-induced toxicity in scleractinian corals. To gain insight into the accommodation of the cellular membrane to oxidative conditions, a pocilloporid coral, Seriatopora caliendrum, was exposed to copper at distinct, environmentally relevant dose for various lengths of time. Glycerophosphocholine profiling of the response of the coral to copper exposure was characterized using a validated method. The results indicate that coral lipid metabolism is programmed to induce membrane alterations in response to the cellular deterioration that occurs during the copper exposure period. Decreasing lyso-phosphatidylcholines and exchanging polyunsaturated phosphatidylcholines for polyunsaturated plasmanylcholines were the initial actions taken to prevent membrane permeabilization. To relax/resist the resulting membrane strain caused by cell/organelle swelling, the coral cells inversely exchanged polyunsaturated plasmanylcholines for polyunsaturated phosphatidylcholines and further increased the levels of monounsaturated glycerophosphocholines. At the same time, the levels of saturated phosphatidylcholines were also increased to increase membrane rigidity and protect against oxidative attack. Interestingly, such alterations in lipid metabolism were also required for membrane fusion to repair the deteriorated membranes by repopulating them with proximal lipid reservoirs, similar to symbiosome membranes. Additionally, increasing saturated and monounsaturated plasmanylcholines and inhibiting the suppression of saturated lyso-phosphatidylcholines were shown to facilitate membrane fusion. Based on the biochemical and biophysical properties of these lipids, the chronic effects of copper, such as coral resistance and growth, can be logically interpreted to result from long-term perturbations in cellular membrane-related functions. In conclusion, the cells of S. caliendrum alter their lipid metabolism and sacrifice fitness to allow the membrane to accommodate copper-induced oxidative situations.

Ocean acidification has no effect on thermal bleaching in the coral Seriatopora caliendrum

The objective of this study was to test whether elevated pCO2 predicted for the year 2100 (85.1 Pa) affects bleaching in the coral Seriatopora caliendrum (Ehrenberg 1834) either independently or interactively with high temperature (30.5 °C). Response variables detected the sequence of events associated with the onset of bleaching: reduction in the photosynthetic performance of symbionts as measured by maximum photochemical efficiency (Fv/Fm) and effective photochemical efficiency (ΔF/Fm′) of PSII, declines in net photosynthesis (Pnet) and photosynthetic efficiency (alpha, α), and finally, reduced chlorophyll a and symbiont concentrations. S. caliendrum was collected from Nanwan Bay, Taiwan, and subjected to combinations of temperature (27.7 vs. 30.5 °C) and pCO2 (45.1 vs. 85.1 Pa) for 14 days. High temperature reduced values of all dependent variables (i.e., bleaching occurred), but high pCO2 did not affect Symbiodinium photophysiology or productivity, and did not cause bleaching. These results suggest that short-term exposure to 81.5 Pa pCO2, alone and in combination with elevated temperature, does not cause or affect coral bleaching.

Exploring the effect of salinity changes on the levels of Hsp60 in the tropical coral Seriatopora caliendrum

Osmotic stress represents a limiting physical parameter for marine organisms and especially for sessile scleractinian corals which are known to be basically stenohaline and osmoconformers. The salinity changes may cause important cellular damage since corals lack any developed physiological regulatory system. One mechanism of reaction to deleterious conditions is the rapid increase of the induction of heat shock proteins. This study highlights the modulation of the expression of a mitochondrial heat shock protein, such as the chaperonin Hsp60, in the animal tissues of the scleractinian coral Seriatopora caliendrum under three salinity scenarios (hypersalinity of 45 ppt, hyposalinity of 25 ppt and extreme hyposalinity of 15 ppt). The study was performed during the time course of a 2-day period and accompanied also by the assessment of the coral health condition. For each salinity stress S. caliendrum responds differently at the morphological and cellular levels, since the Hsp60 exhibited specific patterns of expression and the coral showed different tissue appearance. Furthermore, the response reflects the severity and exposure length of the disturbance. However, the results indicate that S. caliendrum seems able to tolerates high salinity better than low salinity. In particular, in extreme hyposalinity conditions, a considerable gradual down-regulation of Hsp60 was detected accompanied by necrosis and degradation of the coral tissues. The study suggests that Hsp60 may be involved in the mechanisms of cellular response to stress caused by exposure to adverse salinity.

Metabolic costs of larval settlement and metamorphosis in the coral Seriatopora caliendrum under ambient and elevated pCO2

We tested the effects of pCO2 on Seriatopora caliendrum recruits over the first 5.3d of post-settlement existence. In March 2011, 11–20 larvae were settled in glass vials (3.2mL) and incubated at 24.0°C and ~250μmolquantam−2s−1 while supplied with seawater (at 1.4mLs−1) equilibrated with 51.6Pa pCO2 (ambient) or 86.4Pa pCO2. At 51.6Pa pCO2, mean respiration 7h post-settlement was 0.056±0.007nmolO2recruit−1min−1, but rose quickly to 0.095±0.007nmolO2recruit−1min−1 at 3.3d post-settlement, and thereafter declined to 0.075±0.002nmolO2recruit−1min−1 at 5.3d post-settlement (all±SE). Elevated pCO2 depressed respiration of recruits by 19% after 3.3d and 12% overall (i.e., integrated over 5.3d), and while it had no effect on corallite area, elevated pCO2 was associated with weaker adhesion to the glass settlement surface and lower protein biomass. The unique costs of settlement and metamorphosis for S. caliendrum over 5.3d are estimated to be 257mJrecruit−1 at 51.6Pa pCO2, which is less than the energy content of the larvae and recruits.

Physiological development of brooded larvae from two pocilloporid corals in Taiwan

In southern Taiwan, brooded larvae of Pocillopora damicornis and Seriatopora caliendrum are released year-round in synchrony with new moons, and each larval release occurs over multiple days. Using P. damicornis and S. caliendrum as a model system, we describe within-brood variation in larval phenotypes and test for release-day effects that influence larval performance in the pelagic phase. Research was conducted in 2010 using larvae from corals collected in June and July from Nanwan Bay (21°56.179′N, 120°44.85′E). In June, larval phenotypes of both species were characterized immediately following release, and their competency to settle assessed. In July, larvae of P. damicornis were collected on 3 days over the peak release period and incubated for 7–11 days at 28.0 °C and 320 μmol quanta m−2 s−1; their phenotypes and settlement competency were measured every 2 days. P. damicornis larvae released close to peak release were 1.6 times larger in size, contained twice the number of Symbiodinium larva−1, and were 44 % more likely to settle in the first 24 h than larvae released early in the brood. In addition, peak-release larvae respired at a lower rate than larvae released late in the brood. Similarly, S. caliendrum larvae released close to peak release were 1.4 times larger in size and were 33 % more likely to settle in the first 5 h than larvae released early in the brood. In July, P. damicornis larvae differed between early (2 days prior to peak), peak, and late (2 days after peak) release. Protein content of early-release larvae was lower than peak- and late-release larvae, and this difference persisted throughout the development. Further, release day affected the way larval respiration varied throughout development. By showing that brooded coral larvae differ between release days and display maternal effects influencing performance in the swimming phase, our results suggest that pocilloporid corals utilize bet-hedging to increase reproductive success.

The complete mitochondrial genomes of needle corals, Seriatopora spp. (Scleractinia: Pocilloporidae): An idiosyncratic atp8, duplicated trnW gene, and hypervariable regions used to determine species phylogenies and recently diverged populations

Complete DNA sequences were determined for the mitochondrial (mt) genomes of the needle corals, Seriatopora caliendrum (17,011 bp) and S. hystrix (17,060 bp). Gene arrangement of the Seriatopora mt genomes is similar to the 14 currently published scleractinian mitogenomes with three unusual features, including an idiosyncratic atp8, a duplicated trnW ( tRNA TRP ), and a putative control region located between atp6 and nad4. A tp8, located between duplicate trnW genes, showed relatively low amino acid similarity (25.6–34.6%) with those of published scleractinian corals. A reverse-transcription polymerase chain reaction confirmed the transcription of this novel atp8 gene in Seriatopora. A duplicated trnW was detected in the region close to the cox1 gene and shares the highly conserved primary and secondary structure of its original counterpart. The intergenic spacer between atp6 and nad4, which contains several distinct repeated elements, is being designated as the putative control region in the Seriatopora mt genomes. Evaluation of the molecular evolution of several protein-coding genes and intergenic spacers showed 3- to 4-fold higher divergence rates among populations or between species than those published for scleractinian mt genomes. This study not only successfully revealed the phylogenies of S. hystrix and S. caliendrum from the West Pacific Ocean by mtDNA, but also highlighted the potential utilities of mt hypervariable regions in phylogenetic construction below the species level for Seriatopora.

Rhythmical changes in the division and degradation of symbiotic algae in hermatypic corals

Three types of rhythmical changes in division and degradation (digestion) have been found and described in the symbiotic zooxanthellae of the scleractinian coral Seriatopora caliendrum and in the colonial hydroid Myllepora intricata collected at the reef of Sesoko Island (Okinawa, Japan). The first type of changes reported for S. caliendrum is daily variation of the intensity of these two processes peaking at night. The second type of rhythm changes described in S. caliendrum and M. intricata is opposing variations of cell division and degradation levels with a period of three days. The rhythm is disturbed by sudden weather changes or by variations in light. Rhythmical alterations of zooxanthella proliferation and degradation of the third type found in S. caliendrum have a period of 5–6 days and are connected with oppositely directed changes as well as with alterations of the second type. The rhythm of such alterations is not disturbed by abrupt weather changes. All three types of rhythmical changes in zooxanthellae division and digestion observed in hermatypic coral are supposed to be directed to the regulation of the population density of zooxanthellae in organism tissues.

Effect of light intensity on the fatty acid composition of dinoflagellates symbiotic with hermatypic corals

We examined the effects of varying light intensity on fatty acid composition in symbiotic dinoflagellates (SD) isolated from hermatypic corals Millepora intricata , Pocillopora damicornis , Seriatopora caliendrum , Seriatopora hystrix and Stylophora pistillata . The corals were subjected to 95%, 30%, 8% and 2% of incident photosynthetic active radiation (PAR). Irradiance had a significant effect on fatty acid composition of polar lipids and triacylglycerols. SD showed substantial changes in the proportion of 16:0 as a response to variation in PAR. During adaptation to high light, the percentage of 16:0 increased in polar lipids and triacylglycerols. Additionally, the percentage of 14:0, 16:1(n-7) increased in triacylglycerols. Thus, high light conditions lead to an increase in storage products. Polar lipids of SD adapted to low levels of PAR had greater concentrations of 18:4(n-3), 20:5(n-3), 18:5(n-3) and 22:5(n-6) which are commonly involved in the formation of thylakoid membranes. Conversely, the amounts of 20:4(n-6) and 22:6(n-3) increased with increasing irradiance, suggesting an association with photosynthesis. The elevation in percentages of 18:4(n-3), 20:5(n-3) and 18:5(n-3) during exposure to low light was accompanied by an increase in chlorophyll a content in the SD cells. Light-dependent changes in fatty acid composition are probably due to the correlation of activity of photosystems with processes of production and desaturation of fatty acids.

Survivorship of coral juveniles in a fish farm environment

Intensive fish farming is an emerging coastal activity that can potentially enhance sedimentation and promote eutrophication in fringing coral reefs. Here, we investigate the effect of fish farm effluent on the juvenile survivorship of the reef-building coral Seriatopora caliendrum. One-month old juvenile corals (on terracotta tiles) were deployed in fish farm and reference (reef) sites in Bolinao, the Philippines at a depth of 2 m. After forty days, no survivor was recovered in the fish farm, while survivorship was low (11%) in the reference site, with the survivors’ growth rate at 3.3 polyps mo −1 or 1.3 mm 2 mo −1. The fish farm deployed tiles were covered with muddy sediment and were colonized by barnacles, whereas those in the reference site were overgrown by a short stand of filamentous macroalgae. Environmental monitoring revealed higher nutrient levels (ammonia and phosphate), sedimentation rate, and organic matter flux, as well as diminished water transparency and dissolved oxygen levels in the fish farm compared to the reference site. Hence, intensive fish farming offers a suite of physical, chemical and biological modifications of the coastal marine environment which have a detrimental effect on the survivorship of coral juveniles.

A Biochemical Approach for Assessment of the Diversity of Symbiotic Dinoflagellates

The fatty acid composition of polar lipids and triacetylglycerols was determined in different morphophysiological types of symbiotic dinoflagellates isolated from the hydrocoral Millepora intricata and the scleractinian corals Pocillopora damicornis, Seriatopora caliendrum, Seriatopora hystrix, and Stylophora pistillata. The distribution of fatty acids differed fairly markedly among the investigated morphophysiological types of symbiotic dinoflagellates. The differences were found both in polar lipids, which are the structural components of the cell membranes, and storage lipids—triacetylglycerols. It is shown that fatty acids are useful chemotaxonomic markers for symbiotic dinoflagellates. It is assumed that the biochemical differences among the morphophysiological types of symbiotic dinoflagellates can reflect the genetic diversity of these types.

Fatty acid variations in symbiotic dinoflagellates from Okinawan corals

The fatty acid composition of polar lipids and triacylglycerols was determined in different morphophysiological types of symbiotic dinoflagellates (SD) isolated from the hydrocoral Millepora intricata and the scleractinian corals Pocillopora damicornis, Seriatopora caliendrum, Seriatopora hystrix and Stylophora pistillata from a fringing reef of Sesoko Island, Okinawa, Japan. The distribution of the fatty acids among the morphophysiologically distinct types of SD reported in these corals makes it possible to readily distinguish one type of SD from the other. Moreover, differences were found both in polar lipids and triacylglycerols. The polar lipids of SD from M. intricata showed a very distinctive fatty acid profile. A combination of large proportions of 18:4 (n-3), 18:5 (n-3), 22:5 (n-6), and 22:6 (n-3) and negligible amounts of 20:4 (n-6), and 20:5 (n-3) in SD from M. intricata was particularly noteworthy. The fatty acid profiles of SD from P. damicornis and SD isolated from S. caliendrum and S. hystrix differed in the proportion of 18:4 (n-3) and 22:6 (n-3). It is suggested that fatty acids might provide useful information on possible taxonomic differences among symbiotic dinoflagellates. It is assumed that biochemical differences can reflect the genetic diversity of the morphophysiological types of SD associated with several species of hermatypic corals from this region.

Morphophysiological variations of symbiotic dinoflagellates in hermatypic corals from a fringing reef at Sesoko Island

Three types of symbiotic dinoflagellates L (large), B (brown) and G (green) found in hermatypic corals from a fringing reef of Sesoko Island (Okinawa, Japan) differed morphologically, physiologically and biochemically. Colonies of the hydrocoral Millepora intricata hosted symbionts of type L only; scleractinian corals containing type B only were Pocillopora damicornis, type G only were Seriatopora caliendrum and S. hystrix, and both types B and G were found living together in Stylophora pistillata and Echinopora lamellosa. The symbiotic dinoflagellates (SD) differed considerably in cell size, shape and structural elements in coccoid state in hospite. SD of these types also differed in photosynthetic capacities, primary production, pigment accumulation and maximum rates of cell division and degradation.Corals hosting various types of SD significantly differed in light-resistance. Scleractinian corals with symbionts of both types B and G, in the same colony, acclimated to bright light by increasing the relative number of symbionts of type G and acclimated to dim light by increasing the SD number of type B. It was shown that scleractinian corals can photo-acclimate through formation of optimal composition of SD types under various light intensities.