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The Impacts of Ex Situ Transplantation on the Physiology of the Taiwanese Reef-Building Coral Seriatopora hystrix  [PDF]
Anderson B. Mayfield,Tung-Yung Fan,Chii-Shiarng Chen
Journal of Marine Biology , 2013, DOI: 10.1155/2013/569361
Abstract: We sought to determine whether the Indo-Pacific reef-building coral Seriatopora hystrix performs in a similar manner in the laboratory as it does in situ by measuring Symbiodinium density, chlorophyll a (chl-a) concentration, and the maximum quantum yield of photosystem II ( ) at the time of field sampling (in situ), as well as after three weeks of acclimation and one week of experimentation (ex situ). Symbiodinium density was similar between corals of the two study sites, Houbihu (an upwelling reef) and Houwan (a nonupwelling reef), and also remained at similar levels ex situ as in situ. On the other hand, both areal and cell-specific chl-a concentrations approximately doubled ex situ relative to in situ, an increase that may be due to having employed a light regime that differed from that experienced by these corals on the reefs of southern Taiwan from which they were collected. As this change in Symbiodinium chl-a content was documented in corals of both sites, the experiment itself was not biased by this difference. Furthermore, increased by only 1% ex situ relative to in situ, indicating that the corals maintained a similar level of photosynthetic performance as displayed in situ even after one month in captivity. 1. Introduction Molecular biology promises to yield insight into the subcellular mechanisms underlying the stable mutualism between reef-building scleractinians and dinoflagellates of the genus Symbiodinium [1, 2], as well as their macromolecular responses to changes in their environment [3–5]. The latter topic is of particular interest given that global climate change (GCC)-driven temperature and pCO2 increases have been hypothesized to lead to more frequent coral bleaching events in the years to come [6]. Alongside other anthropogenic pressures, such GCC-derived threats have generated an urgent need to shift the monitoring of coral reef health from a retroactive process to a proactive one [7]. Assessment of reef health is currently conducted by visual surveys in which the number of dying or dead corals is quantified (e.g., [8]). However, such late-stage manifestations of health decline likely occurred well after the initial insult. An analysis of the expression or activity of subcellular biomarkers, such as stress genes and proteins, may allow for the determination of which corals are at risk from anthropogenic impacts on a proactive timescale. Such a monitoring approach could potentially allow for scientists and managers to work together to mitigate local-scale insults to reef stability, such as water pollution [9], prior to extensive
The small genetic world of Seriatopora hystrix  [PDF]
Stuart Kininmonth,Madeleine van Oppen,Sarah Castine, et al.
Network Biology , 2012,
Abstract: The exchange of genetic information among coral reefs, through the transport of larvae, is critical to the function of Australia's Great Barrier Reef because it influences recruitment rates and resilience to disturbance. For many species the genetic composition is not homogeneous and is determined, in part, by the character of the complex dispersal pathways that connect the populations situated on each coral reef. One method of measuring these genetic connections is to examine the microsatellite composition of individual corals and then statistically compare populations across the region. We use these connection strengths, derived from a population similarity measure, to create complex networks to describe and analyse the genetic exchange of the brooding coral, Seriatopora hystrix. The network, based on determining the putative parental origin of individual coral colonies, involved sampling 2163 colonies from 47 collection sites and examining 10 microsatellites. A dispersal network was created from the genetic distance DLR values that measure the genetic similarity of each population (defined by the local sampling effort) to every other sampled population based on the microsatellite composition. Graph theory methods show that this network exhibited infrequent long distance links and population clustering which is commonly referred to as small world topology. Comparison with a hydrodynamic based network indicates that the genetic population network topology is similar. This approach shows the genetic structure of the S. hystrix coral follows a small world pattern which supports the results derived from previous hydrodynamic modelling.
Adaptive divergence in a scleractinian coral: physiological adaptation of Seriatopora hystrix to shallow and deep reef habitats
Pim Bongaerts, Cynthia Riginos, Kyra B Hay, Madeleine JH van Oppen, Ove Hoegh-Guldberg, Sophie Dove
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-303
Abstract: The highest survival rates were observed for native transplants (measured 14 months after transplantation), indicating differential selective pressures between habitats. Host-symbiont assemblages remained stable during the experimental duration, demonstrating that the ability to "shuffle" or "switch" symbionts is restricted in S. hystrix. Photo-physiological differences were observed between transplants originating from the shallow and deep habitats, with indirect evidence of an increased heterotrophic capacity in native deep-water transplants (from the 'Deep Slope' habitat). Similar photo-acclimatisation potential was observed between transplants originating from the two shallow habitats ('Back Reef' and 'Upper Slope'), highlighting that their genetic segregation over depth may be due to other, non-photo-physiological traits under selection.This study confirms that the observed habitat partitioning of S. hystrix (and associated Symbiodinium) is reflective of adaptive divergence along a depth gradient. Gene flow appears to be reduced due to divergent selection, highlighting the potential role of ecological mechanisms, in addition to physical dispersal barriers, in the diversification of scleractinian corals and their associated Symbiodinium.Coral reefs are among the most diverse ecosystems on the planet, second only to tropical rainforests in the number of species they harbour [1]. Although the mechanisms that regulate and sustain diversity in both tropical rainforests and coral reefs remain heavily debated, it is clear that the characteristic environmental heterogeneity of these ecosystems must play an integral role by providing important axes for niche diversification [6,7]. In particular, the steep environmental gradients encountered on coral reefs [8] should exert strong differential selective pressures on coral populations and lead to local adaptation at environmental extremes [9]. Yet, direct evidence for the occurrence of such local adaptation across environm
Ecotoxicological Effects of Cosmetic Formulas Containing Chemical and Mineral UV Filters on Seriatopora hystrix Fragments  [PDF]
Marius Anton Ionescu, Marius Anton Ionescu, Catherine Le Breton, Jean-Claude Hubaud, Jean-Eric Branka, Luc Lefeuvre
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2019, DOI: 10.4236/jcdsa.2019.93020
Abstract: Background: Over the last few years sunscreen products have been suspected to be harmful to corals, especially because of their putative negative impact on symbiotic microalgae housed by these cnidarians. Previous publications reported that minerals or chemical UV filters could induce the release of microalgae from corals inducing their bleaching. The study of the ecotoxicity of finished cosmetic products containing these filters is important. Objectives: We sought to assess ex vivo the toxicity of five emulsions containing UV-filters on coral cuttings of Seriatopora hystrix. Materials and Methods: Coral cuttings were put in contact with 5 different emulsions containing UV-filters. The toxicity readout was the ability to induce polyp retraction and/or fragment bleaching of the coral cuttings of Seriatopora hystrix. Results: In our experimental conditions, none of the five tested formulas neither induced any significant polyp retraction nor triggered fragment bleaching of the coral. Conclusions: The five tested emulsions containing UV-filters did not modify coral cuttings. In vivo, larger tests are necessary to verify the results of this ex vivo pilot study.
Symbiodinium Genotypic and Environmental Controls on Lipids in Reef Building Corals  [PDF]
Timothy F. Cooper, Michael Lai, Karin E. Ulstrup, Sandra M. Saunders, Gavin R. Flematti, Ben Radford, Madeleine J. H. van Oppen
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0020434
Abstract: Background Lipids in reef building corals can be divided into two classes; non-polar storage lipids, e.g. wax esters and triglycerides, and polar structural lipids, e.g. phospholipids and cholesterol. Differences among algal endosymbiont types are known to have important influences on processes including growth and the photobiology of scleractinian corals yet very little is known about the role of symbiont types on lipid energy reserves. Methodology/Principal Findings The ratio of storage lipid and structural lipid fractions of Scott Reef corals were determined by thin layer chromatography. The lipid fraction ratio varied with depth and depended on symbiont type harboured by two corals (Seriatopora hystrix and Pachyseris speciosa). S. hystrix colonies associated with Symbiodinium C1 or C1/C# at deep depths (>23 m) had lower lipid fraction ratios (i.e. approximately equal parts of storage and structural lipids) than those with Symbiodinium D1 in shallow depths (<23 m), which had higher lipid fraction ratios (i.e. approximately double amounts of storage relative to structural lipid). Further, there was a non-linear relationship between the lipid fraction ratio and depth for S. hystrix with a modal peak at ~23 m coinciding with the same depth as the shift from clade D to C types. In contrast, the proportional relationship between the lipid fraction ratio and depth for P. speciosa, which exhibited high specificity for Symbiodinium C3 like across the depth gradient, was indicative of greater amounts of storage lipids contained in the deep colonies. Conclusions/Significance This study has demonstrated that Symbiodinium exert significant controls over the quality of coral energy reserves over a large-scale depth gradient. We conclude that the competitive advantages and metabolic costs that arise from flexible associations with divergent symbiont types are offset by energetic trade-offs for the coral host.
A comparative study of the components of the hard coral Seriatopora hystrix and the soft coral Xenia umbellata along the Jeddah coast, Saudi Arabia
Al-Sofyani,A. A; Niaz,G. R;
Revista de biología marina y oceanografía , 2007, DOI: 10.4067/S0718-19572007000300001
Abstract: in this study, the structure of the polyps and the cell types of the hard coral seriatopora hystrix and the soft coral xenia umbellata were compared, together with the composition of the fatty acids in their tissues. s. hystrix displayed an apparent lack of specialized feeding cells, notably the relatively small number of mucous gland cells and the low percentage of venom containing nematocysts. p-mastigophores accounted for 1.52-5.7% and, b-mastigophores for 1.28% of the nematocysts. conversely there was a high percentage of holotrichs nematocysts (24.86 - 55.5%) in the tentacles and mesenterial filaments respectively. zooxanthellae were abundant in the gastrodermis. these charateristics suggest that s. hystrix relies essentially upon autotrophic nutrition. the polyps of x. umbellata were devoid of cnidae, and mucous glands were in abundance, particularly in the lower part of the polyp. the presence of particulate matter in the coelenteron, and low number of zooxanthellae indicate that x. umbellata is a suspension feeder, using mucus to trap the particles on the pinnate tentacles. differences were also revealed by a comparative study of their chemical composition. x. umbellata had a high protein and lipid content, whilst s. hystrix was characterized by high calcium carbonate content. in s. hystrix, the fatty acids were found to be predominantly saturated fatty acids (87.3%), the most abundant being 16:0 and 18:0. x. umbellata showed a predominance of unsaturated fatty acids (77.7%), the most abundant being 16:1 and 18:1. the differences in morphology and in biochemical composition suggest that s. hystrix has a greater reliance on autotrophic feeding whilst x. umbellata is a more heterotrophic suspension feeder
Assessing the Impacts of Experimentally Elevated Temperature on the Biological Composition and Molecular Chaperone Gene Expression of a Reef Coral  [PDF]
Anderson B. Mayfield, Li-Hsueh Wang, Pei-Ciao Tang, Tung-Yung Fan, Yi-Yuong Hsiao, Ching-Lin Tsai, Chii-Shiarng Chen
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026529
Abstract: Due to the potential for increasing ocean temperatures to detrimentally impact reef-building corals, there is an urgent need to better understand not only the coral thermal stress response, but also natural variation in their sub-cellular composition. To address this issue, while simultaneously developing a molecular platform for studying one of the most common Taiwanese reef corals, Seriatopora hystrix, 1,092 cDNA clones were sequenced and characterized. Subsequently, RNA, DNA and protein were extracted sequentially from colonies exposed to elevated (30°C) temperature for 48 hours. From the RNA phase, a heat shock protein-70 (hsp70)-like gene, deemed hsp/c, was identified in the coral host, and expression of this gene was measured with real-time quantitative PCR (qPCR) in both the host anthozoan and endosymbiotic dinoflagellates (genus Symbiodinium). While mRNA levels were not affected by temperature in either member, hsp/c expression was temporally variable in both and co-varied within biopsies. From the DNA phase, host and Symbiodinium hsp/c genome copy proportions (GCPs) were calculated to track changes in the biological composition of the holobiont during the experiment. While there was no temperature effect on either host or Symbiodinium GCP, both demonstrated significant temporal variation. Finally, total soluble protein was responsive to neither temperature nor exposure time, though the protein/DNA ratio varied significantly over time. Collectively, it appears that time, and not temperature, is a more important driver of the variation in these parameters, highlighting the need to consider natural variation in both gene expression and the molecular make-up of coral holobionts when conducting manipulative studies. This represents the first study to survey multiple macromolecules from both compartments of an endosymbiotic organism with methodologies that reflect their dual-compartmental nature, ideally generating a framework for assessing molecular-level changes within corals and other endosymbioses exposed to changes in their environment.
Life History Changes in Coral Fluorescence and the Effects of Light Intensity on Larval Physiology and Settlement in Seriatopora hystrix  [PDF]
Melissa S. Roth, Tung-Yung Fan, Dimitri D. Deheyn
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059476
Abstract: Fluorescence is common in both coral adult and larval stages, and is produced by fluorescent proteins that absorb higher energy light and emit lower energy light. This study investigated the changes of coral fluorescence in different life history stages and the effects of parental light environment on larval fluorescence, larval endosymbiotic dinoflagellate abundance, larval size and settlement in the brooding coral Seriatopora hystrix. Data showed that coral fluorescence changed during development from green in larvae to cyan in adult colonies. In larvae, two green fluorescent proteins (GFPs) co-occur where the peak emission of one GFP overlaps with the peak excitation of the second GFP allowing the potential for energy transfer. Coral larvae showed great variation in GFP fluorescence, dinoflagellate abundance, and size. There was no obvious relationship between green fluorescence intensity and dinoflagellate abundance, green fluorescence intensity and larval size, or dinoflagellate abundance and larval size. Larvae of parents from high and low light treatments showed similar green fluorescence intensity, yet small but significant differences in size, dinoflagellate abundance, and settlement. The large variation in larval physiology combined with subtle effects of parental environment on larval characteristics seem to indicate that even though adult corals produce larvae with a wide range of physiological capacities, these larvae can still show small preferences for settling in similar habitats as their parents. These data highlight the importance of environmental conditions at the onset of life history and parent colony effects on coral larvae.
Hourglass Mechanism with Temperature Compensation in the Diel Periodicity of Planulation of the Coral, Seriatopora hystrix  [PDF]
Che-Hung Lin, Keryea Soong, Tung-Yung Fan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064584
Abstract: Brooding corals often exhibit daily planulation peaks in certain phases of lunar months during their reproductive season. The mechanism controlling this diurnal phenomenon, however, remains uncertain. Seriatopora hystrix populations of Southern Taiwan exhibit a highly synchronized planulation rhythm characterized by pre-dawn peak release episodes over a period of 4–6 days per month throughout the year. In this study, controlled light-dark cycles and temperatures were used to study the mechanism of the diel planulation rhythm in the laboratory. Seriatopora hystrix did not release planulae under continuous light or continuous darkness. Thus, the lack of free-run did not support a regulatory mechanism involving an endogenous oscillator. Under some lighting conditions, planula release occurred in two peaks per day. Both peaks always occur under dark phases of various light-dark cycles in the laboratory. The first peak occurred when the dark period just started, which might be stimulated by an abrupt transition between light and darkness. The second, pre-dawn peak consistently occurred 23 hrs after application of light. We concluded that this peak of planula release of S. hystrix was cued by sunrise of the previous day. Temperature treatments at 1°C intervals from 23.5–28.5°C did not change the diel time of planula release. We suggest that the temperature compensation exhibited in the hourglass model of this species may have a common origin as that of the oscillator model of circadian clocks, due to the similar duration (23 h) and period (~24 h) between the two. The timing mechanism of planulation discovered here represents an intermediate stage between the hourglass and the oscillator models.
The Mangrove Nursery Paradigm Revisited: Otolith Stable Isotopes Support Nursery-to-Reef Movements by Indo-Pacific Fishes  [PDF]
Ismael A. Kimirei, Ivan Nagelkerken, Yunus D. Mgaya, Chantal M. Huijbers
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066320
Abstract: Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith stable carbon and oxygen isotopes, to investigate for the first time the degree to which multiple tropical juvenile habitats subsidize coral reef fish populations in the Indo Pacific (Tanzania). Otoliths of three reef fish species (Lethrinus harak, L. lentjan and Lutjanus fulviflamma) were collected in mangrove, seagrass and coral reef habitats and analyzed for stable isotope ratios in the juvenile and adult otolith zones. δ13C signatures were significantly depleted in the juvenile compared to the adult zones, indicative of different habitat use through ontogeny. Maximum likelihood analysis identified that 82% of adult reef L. harak had resided in either mangrove (29%) or seagrass (53%) or reef (18%) habitats as juveniles. Of adult L. fulviflamma caught from offshore reefs, 99% had passed through mangroves habitats as juveniles. In contrast, L. lentjan adults originated predominantly from coral reefs (65–72%) as opposed to inshore vegetated habitats (28–35%). This study presents conclusive evidence for a nursery role of Indo-Pacific mangrove habitats for reef fish populations. It shows that intertidal habitats that are only temporarily available can form an important juvenile habitat for some species, and that reef fish populations are often replenished by multiple coastal habitats. Maintaining connectivity between inshore vegetated habitats and coral reefs, and conserving habitat mosaics rather than single nursery habitats, is a major priority for the sustainability of various Indo Pacific fish populations.
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