Metagenomic analysis of the microbial community associated with the coral Porites astreoides.

PubMed

Wegley, Linda; Edwards, Robert; Rodriguez-Brito, Beltran; Liu, Hong; Rohwer, Forest

2007-11-01

The coral holobiont is a dynamic assemblage of the coral animal, zooxanthellae, endolithic algae and fungi, Bacteria,Archaea and viruses. Zooxanthellae and some Bacteria form relatively stable and species-specific associations with corals. Other associations are less specific; coral-associated Archaea differ from those in the water column, but the same archaeal species may be found on different coral species. It has been hypothesized that the coral animal can adapt to differing ecological niches by 'switching' its microbial associates. In the case of corals and zooxanthellae, this has been termed adaptive bleaching and it has important implications for carbon cycling within the coral holobiont and ultimately the survival of coral reefs. However, the roles of other components of the coral holobiont are essentially unknown. To better understand these other coral associates, a fractionation procedure was used to separate the microbes, mitochondria and viruses from the coral animal cells and zooxanthellae. The resulting metagenomic DNA was sequenced using pyrosequencing. Fungi, Bacteria and phage were the most commonly identified organisms in the metagenome. Three of the four fungal phyla were represented, including a wide diversity of fungal genes involved in carbon and nitrogen metabolism, suggesting that the endolithic community is more important than previously appreciated. In particular, the data suggested that endolithic fungi could be converting nitrate and nitrite to ammonia, which would enable fixed nitrogen to cycle within the coral holobiont. The most prominent bacterial groups were Proteobacteria (68%), Firmicutes (10%), Cyanobacteria (7%) and Actinobacteria (6%). Functionally, the bacterial community was primarily heterotrophic and included a number of pathways for the degradation of aromatic compounds, the most abundant being the homogentisate pathway. The most abundant phage family was the ssDNA Microphage and most of the eukaryotic viruses were most

A snapshot of a coral "holobiont": a transcriptome assembly of the scleractinian coral, porites, captures a wide variety of genes from both the host and symbiotic zooxanthellae.

PubMed

Shinzato, Chuya; Inoue, Mayuri; Kusakabe, Makoto

2014-01-01

Massive scleractinian corals of the genus Porites are important reef builders in the Indo-Pacific, and they are more resistant to thermal stress than other stony corals, such as the genus Acropora. Because coral health and survival largely depend on the interaction between a coral host and its symbionts, it is important to understand the molecular interactions of an entire "coral holobiont". We simultaneously sequenced transcriptomes of Porites australiensis and its symbionts using the Illumina Hiseq2000 platform. We obtained 14.3 Gbp of sequencing data and assembled it into 74,997 contigs (average: 1,263 bp, N50 size: 2,037 bp). We successfully distinguished contigs originating from the host (Porites) and the symbiont (Symbiodinium) by aligning nucleotide sequences with the decoded Acropora digitifera and Symbiodinium minutum genomes. In contrast to previous coral transcriptome studies, at least 35% of the sequences were found to have originated from the symbionts, indicating that it is possible to analyze both host and symbiont transcriptomes simultaneously. Conserved protein domain and KEGG analyses showed that the dataset contains broad gene repertoires of both Porites and Symbiodinium. Effective utilization of sequence reads revealed that the polymorphism rate in P. australiensis is 1.0% and identified the major symbiotic Symbiodinium as Type C15. Analyses of amino acid biosynthetic pathways suggested that this Porites holobiont is probably able to synthesize most of the common amino acids and that Symbiodinium is potentially able to provide essential amino acids to its host. We believe this to be the first molecular evidence of complementarity in amino acid metabolism between coral hosts and their symbionts. We successfully assembled genes originating from both the host coral and the symbiotic Symbiodinium to create a snapshot of the coral holobiont transcriptome. This dataset will facilitate a deeper understanding of molecular mechanisms of coral symbioses

Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

PubMed

Levas, Stephen J; Grottoli, Andréa G; Hughes, Adam; Osburn, Christopher L; Matsui, Yohei

2013-01-01

Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13)C of the skeletal, δ(13)C, and δ(15)N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13)C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of

Physiological and Biogeochemical Traits of Bleaching and Recovery in the Mounding Species of Coral Porites lobata: Implications for Resilience in Mounding Corals

PubMed Central

Levas, Stephen J.; Grottoli, Andréa G.; Hughes, Adam; Osburn, Christopher L.; Matsui, Yohei

2013-01-01

Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ13C of the skeletal, δ13C, and δ15N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via 13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of fixed carbon

Skeletal records of community-level bleaching in Porites corals from Palau

NASA Astrophysics Data System (ADS)

Barkley, Hannah C.; Cohen, Anne L.

2016-12-01

Tropical Pacific sea surface temperature is projected to rise an additional 2-3 °C by the end of this century, driving an increase in the frequency and intensity of coral bleaching. With significant global coral reef cover already lost due to bleaching-induced mortality, efforts are underway to identify thermally tolerant coral communities that might survive projected warming. Massive, long-lived corals accrete skeletal bands of anomalously high density in response to episodes of thermal stress. These "stress bands" are potentially valuable proxies for thermal tolerance, but to date their application to questions of community bleaching history has been limited. Ecological surveys recorded bleaching of coral communities across the Palau archipelago during the 1998 and 2010 warm events. Between 2011 and 2015, we extracted skeletal cores from living Porites colonies at 10 sites spanning barrier reef and lagoon environments and quantified the proportion of stress bands present in each population during bleaching years. Across Palau, the prevalence of stress bands tracked the severity of thermal stress, with more stress bands occurring in 1998 (degree heating weeks = 13.57 °C-week) than during the less severe 2010 event (degree heating weeks = 4.86 °C-week). Stress band prevalence also varied by reef type, as more corals on the exposed barrier reef formed stress bands than did corals from sheltered lagoon environments. Comparison of Porites stress band prevalence with bleaching survey data revealed a strong correlation between percent community bleaching and the proportion of colonies with stress bands in each year. Conversely, annual calcification rates did not decline consistently during bleaching years nor did annually resolved calcification histories always track interannual variability in temperature. Our data suggest that stress bands in massive corals contain valuable information about spatial and temporal trends in coral reef bleaching and can aid in

Sex-associated variations in coral skeletal oxygen and carbon isotopic composition of Porites panamensis in the southern Gulf of California

NASA Astrophysics Data System (ADS)

Cabral-Tena, Rafael A.; Sánchez, Alberto; Reyes-Bonilla, Héctor; Ruvalcaba-Díaz, Angel H.; Balart, Eduardo F.

2016-05-01

variables; therefore, variations in skeletal δ13C appear to be driven mainly by metabolic effects. Our results support the hypothesis of a sex-associated difference in skeletal δ18O and δ13C signal, and suggest that environmental conditions and coral growth parameters affect skeletal isotopic signals differently in each sex. Although these findings relate to one gonochoric brooding species, they may have some implications for the more commonly used gonochoric spawning species such as Porites lutea and Porites lobata.

A Snapshot of a Coral “Holobiont”: A Transcriptome Assembly of the Scleractinian Coral, Porites, Captures a Wide Variety of Genes from Both the Host and Symbiotic Zooxanthellae

PubMed Central

Shinzato, Chuya; Inoue, Mayuri; Kusakabe, Makoto

2014-01-01

Massive scleractinian corals of the genus Porites are important reef builders in the Indo-Pacific, and they are more resistant to thermal stress than other stony corals, such as the genus Acropora. Because coral health and survival largely depend on the interaction between a coral host and its symbionts, it is important to understand the molecular interactions of an entire “coral holobiont”. We simultaneously sequenced transcriptomes of Porites australiensis and its symbionts using the Illumina Hiseq2000 platform. We obtained 14.3 Gbp of sequencing data and assembled it into 74,997 contigs (average: 1,263 bp, N50 size: 2,037 bp). We successfully distinguished contigs originating from the host (Porites) and the symbiont (Symbiodinium) by aligning nucleotide sequences with the decoded Acropora digitifera and Symbiodinium minutum genomes. In contrast to previous coral transcriptome studies, at least 35% of the sequences were found to have originated from the symbionts, indicating that it is possible to analyze both host and symbiont transcriptomes simultaneously. Conserved protein domain and KEGG analyses showed that the dataset contains broad gene repertoires of both Porites and Symbiodinium. Effective utilization of sequence reads revealed that the polymorphism rate in P. australiensis is 1.0% and identified the major symbiotic Symbiodinium as Type C15. Analyses of amino acid biosynthetic pathways suggested that this Porites holobiont is probably able to synthesize most of the common amino acids and that Symbiodinium is potentially able to provide essential amino acids to its host. We believe this to be the first molecular evidence of complementarity in amino acid metabolism between coral hosts and their symbionts. We successfully assembled genes originating from both the host coral and the symbiotic Symbiodinium to create a snapshot of the coral holobiont transcriptome. This dataset will facilitate a deeper understanding of molecular mechanisms of coral

Community Shifts in the Surface Microbiomes of the Coral Porites astreoides with Unusual Lesions

PubMed Central

Meyer, Julie L.; Paul, Valerie J.; Teplitski, Max

2014-01-01

Apical lesions on Porites astreoides were characterized by the appearance of a thin yellow band, which was preceded by bleaching of the coral tissues and followed by a completely denuded coral skeleton, which often harbored secondary macroalgal colonizers. These characteristics have not been previously described in Porites and do not match common Caribbean coral diseases. The lesions were observed only in warmer months and at shallow depths on the fore reef in Belize. Analysis of the microbial community composition based on the V4 hypervariable region of 16S ribosomal RNA genes revealed that the surface microbiomes associated with nonsymptomatic corals were dominated by the members of the genus Endozoicomonas, consistent with other studies. Comparison of the microbiomes of nonsymptomatic and lesioned coral colonies sampled in July and September revealed two distinct groups, inconsistently related to the disease state of the coral, but showing some temporal signal. The loss of Endozoicomonas was characteristic of lesioned corals, which also harbored potential opportunistic pathogens such as Alternaria, Stenotrophomonas, and Achromobacter. The presence of lesions in P. astreoides coincided with a decrease in the relative abundance of Endozoicomonas, rather than the appearance of specific pathogenic taxa. PMID:24937478

Effects of intermittent flow and irradiance level on back reef Porites corals at elevated seawater temperatures

USGS Publications Warehouse

Smith, L.W.; Birkeland, C.

2007-01-01

Corals inhabiting shallow back reef habitats are often simultaneously exposed to elevated seawater temperatures and high irradiance levels, conditions known to cause coral bleaching. Water flow in many tropical back reef systems is tidally influenced, resulting in semi-diurnal or diurnal flow patterns. Controlled experiments were conducted to test effects of semi-diurnally intermittent water flow on photoinhibition and bleaching of the corals Porites lobata and P. cylindrica kept at elevated seawater temperatures and different irradiance levels. All coral colonies were collected from a shallow back reef pool on Ofu Island, American Samoa. In the high irradiance experiments, photoinhibition and bleaching were less for both species in the intermittent high-low flow treatment than in the constant low flow treatment. In the low irradiance experiments, there were no differences in photoinhibition or bleaching for either species between the flow treatments, despite continuously elevated seawater temperatures. These results suggest that intermittent flow associated with semi-diurnal tides, and low irradiances caused by turbidity or shading, may reduce photoinhibition and bleaching of back reef corals during warming events. ?? 2006 Elsevier B.V. All rights reserved.

Trace metal anomalies in bleached Porites coral at Meiji Reef, tropical South China Sea

NASA Astrophysics Data System (ADS)

Li, Shu; Yu, Kefu; Zhao, Jianxin; Feng, Yuexing; Chen, Tianran

2017-01-01

Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium (Cr), copper (Cu), molybdenum (Mo), manganese (Mn), lead (Pb), tin (Sn), titanium (Ti), vanadium (V), and yttrium (Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea (SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.

Highly heterogeneous bacterial communities associated with the South China Sea reef corals Porites lutea, Galaxea fascicularis and Acropora millepora.

PubMed

Li, Jie; Chen, Qi; Zhang, Si; Huang, Hui; Yang, Jian; Tian, Xin-Peng; Long, Li-Juan

2013-01-01

Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.

Evidence for the Thermal Bleaching of Porites Corals From 4.0 ka B.P. in the Northern South China Sea

NASA Astrophysics Data System (ADS)

Xu, Shendong; Yu, Kefu; Tao, Shichen; Wu, Chung-Che; Wang, Yinghui; Jiang, Wei; Wang, Shaopeng; Shen, Chuan-Chou

2018-01-01

Coral bleaching is becoming a serious issue for coral reefs under the stress of global warming. However, whether it has occurred in the past in times of thermal stress remains unclear. Moreover, an understanding of historic coral bleaching events would greatly improve our insight into the adaptive capabilities of corals under such stresses. It is known that Porites corals, a massive coral, have relatively high levels of symbiotic zooxanthellae and a strong thermal tolerance when compared with most other corals (and particularly branched corals). Thus, growth hiatuses and/or mortality surfaces of fossil Porites may be used to indicate past ecological or environmental stress events, such as severe bleaching. In this study, monthly geochemical and isotopic environmental proxies of four fossil Porites corals with well-preserved growth hiatuses and mortality surfaces (aged 3,800-4,200 years before 2013 A.D.), collected from Wenchang fringing reef, Hainan Island, Northern South China Sea were analyzed. Specifically, the Sr/Ca, δ18O, and δ13C were measured with a monthly resolution for each sample. These environmental proxies were used to reconstruct the sea surface temperature (SST), sea surface salinity (SSS), and physiological activity of the coral at the time when the growth hiatuses and/or mortality surfaces occurred. These data were subsequently used to determine the causes of coral mortality and growth discontinuity in each case. The results show that growth hiatuses and mortalities mainly occurred in summer, with high SST (31-34°C) and SSS (32.8-38.4). In addition, abrupt negative shifts of 2-3‰ in δ13C were observed in almost all of the surfaces of growth hiatus and mortality, indicating a dramatically reduced level of photosynthetic activity in symbiotic zooxanthellae. Because of the above reasons, we conclude that the frequently observed mortality and growth discontinuity of Porites corals from the mid-Holocene is evidence for thermal bleaching events in

Chemically-mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

USGS Publications Warehouse

Paul, Valerie J.; Kuffner, Ilsa B.; Walters, Linda J.; Ritson-Williams, Raphael; Beach, Kevin S.; Becerro, Mikel A.

2011-01-01

Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment.

Surviving Coral Bleaching Events: Porites Growth Anomalies on the Great Barrier Reef

PubMed Central

Cantin, Neal E.; Lough, Janice M.

2014-01-01

Mass coral bleaching affected large parts of the Great Barrier Reef (GBR) in 1998 and 2002. In this study, we assessed if signatures of these major thermal stress events were recorded in the growth characteristics of massive Porites colonies. In 2005 a suite of short (<50 cm) cores were collected from apparently healthy, surviving Porites colonies, from reefs in the central GBR (18–19°S) that have documented observations of widespread bleaching. Sites included inshore (Nelly Bay, Pandora Reef), annually affected by freshwater flood events, midshelf (Rib Reef), only occasionally affected by freshwater floods and offshore (Myrmidon Reef) locations primarily exposed to open ocean conditions. Annual growth characteristics (extension, density and calcification) were measured in 144 cores from 79 coral colonies and analysed over the common 24-year period, 1980–2003. Visual examination of the annual density bands revealed growth hiatuses associated with the bleaching years in the form of abrupt decreases in annual linear extension rates, high density stress bands and partial mortality. The 1998 mass-bleaching event reduced Porites calcification by 13 and 18% on the two inshore locations for 4 years, followed by recovery to baseline calcification rates in 2002. Evidence of partial mortality was apparent in 10% of the offshore colonies in 2002; however no significant effects of the bleaching events were evident in the calcification rates at the mid shelf and offshore sites. These results highlight the spatial variation of mass bleaching events and that all reef locations within the GBR were not equally stressed by the 1998 and 2002 mass bleaching events, as some models tend to suggest, which enabled recovery of calcification on the GBR within 4 years. The dynamics in annual calcification rates and recovery displayed here should be used to improve model outputs that project how coral calcification will respond to ongoing warming of the tropical oceans. PMID:24586377

Surviving coral bleaching events: porites growth anomalies on the Great Barrier Reef.

PubMed

Cantin, Neal E; Lough, Janice M

2014-01-01

Mass coral bleaching affected large parts of the Great Barrier Reef (GBR) in 1998 and 2002. In this study, we assessed if signatures of these major thermal stress events were recorded in the growth characteristics of massive Porites colonies. In 2005 a suite of short (<50 cm) cores were collected from apparently healthy, surviving Porites colonies, from reefs in the central GBR (18-19°S) that have documented observations of widespread bleaching. Sites included inshore (Nelly Bay, Pandora Reef), annually affected by freshwater flood events, midshelf (Rib Reef), only occasionally affected by freshwater floods and offshore (Myrmidon Reef) locations primarily exposed to open ocean conditions. Annual growth characteristics (extension, density and calcification) were measured in 144 cores from 79 coral colonies and analysed over the common 24-year period, 1980-2003. Visual examination of the annual density bands revealed growth hiatuses associated with the bleaching years in the form of abrupt decreases in annual linear extension rates, high density stress bands and partial mortality. The 1998 mass-bleaching event reduced Porites calcification by 13 and 18% on the two inshore locations for 4 years, followed by recovery to baseline calcification rates in 2002. Evidence of partial mortality was apparent in 10% of the offshore colonies in 2002; however no significant effects of the bleaching events were evident in the calcification rates at the mid shelf and offshore sites. These results highlight the spatial variation of mass bleaching events and that all reef locations within the GBR were not equally stressed by the 1998 and 2002 mass bleaching events, as some models tend to suggest, which enabled recovery of calcification on the GBR within 4 years. The dynamics in annual calcification rates and recovery displayed here should be used to improve model outputs that project how coral calcification will respond to ongoing warming of the tropical oceans.

Metagenomic analysis indicates that stressors induce production of herpes-like viruses in the coral Porites compressa

PubMed Central

Vega Thurber, Rebecca L.; Barott, Katie L.; Hall, Dana; Liu, Hong; Rodriguez-Mueller, Beltran; Desnues, Christelle; Edwards, Robert A.; Haynes, Matthew; Angly, Florent E.; Wegley, Linda; Rohwer, Forest L.

2008-01-01

During the last several decades corals have been in decline and at least one-third of all coral species are now threatened with extinction. Coral disease has been a major contributor to this threat, but little is known about the responsible pathogens. To date most research has focused on bacterial and fungal diseases; however, viruses may also be important for coral health. Using a combination of empirical viral metagenomics and real-time PCR, we show that Porites compressa corals contain a suite of eukaryotic viruses, many related to the Herpesviridae. This coral-associated viral consortium was found to shift in response to abiotic stressors. In particular, when exposed to reduced pH, elevated nutrients, and thermal stress, the abundance of herpes-like viral sequences rapidly increased in 2 separate experiments. Herpes-like viral sequences were rarely detected in apparently healthy corals, but were abundant in a majority of stressed samples. In addition, surveys of the Nematostella and Hydra genomic projects demonstrate that even distantly related Cnidarians contain numerous herpes-like viral genes, likely as a result of latent or endogenous viral infection. These data support the hypotheses that corals experience viral infections, which are exacerbated by stress, and that herpes-like viruses are common in Cnidarians. PMID:19017800

Chemically mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

USGS Publications Warehouse

Paul, V.J.; Kuffner, I.B.; Walters, L.J.; Ritson-Williams, R.; Beach, K.S.; Becerro, M.A.

2011-01-01

Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment. ?? 2011 Inter-Research.

Comparative demography of two common scleractinian corals: Orbicella annularis and Porites astreoides

PubMed Central

Mercado-Molina, Alex; Reyes-Maldonado, Koralis; Vélez, Yaileen; Ruiz-Díaz, Claudia P.; Sabat, Alberto

2017-01-01

Background Studies directed at understanding the demography and population dynamics of corals are relatively scarce. This limits our understanding of both the dynamics of coral populations and our capacity to develop management and conservation initiatives directed at conserving such ecosystems. Methods From 2012 to 2014, we collected data on the growth, survival, and recruitment rates of two common Caribbean coral species, the stress-tolerant Orbicella annularis and the weedy Porites astreoides. A set of size-based population matrix model was developed for two localities in Northeastern Puerto Rico and used to estimate population growth rates (λ) and determine the life cycle transition(s) that contribute the most to spatiotemporal differences in λs. The model was parameterized by following the fate of 100 colonies of each species at the two sites for two years. Results Our data indicate that spatial variability in vital rates of both species was higher than temporal variability. During the first year, populations of O. annularis exhibited λs below equilibrium at Carlos Rosario (0.817) and Palomino (0.694), followed by a considerable decline at both sites during the second year (0.700 and 0.667). Populations of P. astreoides showed higher λs than O. annularis during the first census period at Carlos Rosario (0.898) and Palomino (0.894) with a decline at one of the sites (0.681 and 0.893) during the second census period. Colony fate in both species exhibited a significant interaction with respect to location but not to time (G2 = 20.96; df = 3 for O. annularis and G2 = 9.55; df = 3 for P. astreoides). Discussion The similar variability of λs as well as the similar survival rates for both species during the two-year census period (2012–2014) show similar variability on demographic patterns in space and time. Our results suggest that location rather than time is important for the resiliency in coral colonies. Also, P. astreoides will show higher resistance to

Holocene key coral species in the Northwest Pacific: indicators of reef formation and reef ecosystem responses to global climate change and anthropogenic stresses in the near future

NASA Astrophysics Data System (ADS)

Hongo, Chuki

2012-03-01

The geological record of key coral species that contribute to reef formation and maintenance of reef ecosystems is important for understanding the ecosystem response to global-scale climate change and anthropogenic stresses in the near future. Future responses can be predicted from accumulated data on Holocene reef species identified in drillcore and from data on raised reef terraces. The present study analyzes a dataset based on 27 drillcores, raised reef terraces, and 134 radiocarbon and U-Th ages from reefs of the Northwest Pacific, with the aim of examining the role of key coral species in reef growth and maintenance for reef ecosystem during Holocene sea-level change. The results indicate a latitudinal change in key coral species: arborescent Acropora (Acropora intermedia and Acropora muricata) was the dominant reef builder at reef crests in the tropics, whereas Porites (Porites australiensis, Porites lutea, and Porites lobata) was the dominant contributor to reef growth in the subtropics between 10,000 and 7000 cal. years BP (when the rate of sea-level rise was 10 m/ka). Acropora digitifera, Acropora hyacinthus, Acropora robusta/A. abrotanoides, Isopora palifera, Favia stelligera, and Goniastrea retiformis from the corymbose and tabular Acropora facies were the main key coral species at reef crests between 7000 and 5000 cal. years BP (when the rate of sea-level rise was 5 m/ka) and during the following period of stable sea-level. Massive Porites (P. australiensis, P. lutea, and P. lobata) contributed to reef growth in shallow lagoons during the period of stable sea level. Key coral species from the corymbose and tabular Acropora facies have the potential to build reefs and maintain ecosystems in the near future under a global sea-level rise of 2-6 m/ka, as do key coral species from the arborescent Acropora facies and massive Porites facies, which show vigorous growth and are tolerant to relatively deep-water, low-energy environments. However, these species

Macrobioerosion in Porites corals in subtropical northern South China Sea: a limiting factor for high-latitude reef framework development

NASA Astrophysics Data System (ADS)

Chen, Tianran; Li, Shu; Yu, Kefu

2013-03-01

Bioerosion is an important limiting factor in carbonate accretion and reef framework development; however, few studies have quantified the direct impact of macroborers on high-latitude coral communities, which are viewed as potential refuge during a period of global warming. In this study, internal macrobioerosion of Porites corals was examined at Daya Bay, subtropical northern South China Sea. The principal borers were the bivalve Lithophaga spp. and the sponges Cliona spp. and Cliothosa spp. (≥80 %), while sipunculid and polychaete worms and barnacles accounted for small amounts of bioerosion (≤20 %). Porites corals were heavily bioeroded in areas impacted by aquacultural and urban activities (10.34-27.55 %) compared with corals in relatively unpolluted areas (2.18-6.76 %). High levels of bioerosion, especially boring bivalve infestation, significantly weaken the corals and increase their susceptibility to dislodgement and fragmentation in typhoons, limiting accumulation of limestone framework. This study implies that carbonate accretion and reef development for high-latitude coral communities may be limited in future high-CO2 and eutrophication-stressed environments.

Corallite skeletal morphological variation in Hawaiian Porites lobata

NASA Astrophysics Data System (ADS)

Tisthammer, Kaho H.; Richmond, Robert H.

2018-06-01

Due to their high morphological plasticity and complex evolutionary history, the species boundaries of many reef-building corals are poorly understood. The skeletal structures of corals have traditionally been used for species identification, but these structures can be highly variable, and currently we lack knowledge regarding the extent of morphological variation within species. Porites species are notorious for their taxonomic difficulties, both morphologically and genetically, and currently there are several unresolved species complexes in the Pacific. Despite its ubiquitous presence and broad use in coral research, Porites lobata belongs to one such unresolved species complex. To understand the degree of intraspecific variation in skeletal morphology, 120 corallites from the Hawaiian P. lobata were examined. A subset of samples from two genetically differentiated populations from contrasting high- and low-stress environments in Maunalua Bay, Hawaii, were then quantitatively analyzed using multivariate morphometrics. Our observations revealed high intraspecific variation in corallite morphology, as well as significant morphological differences between the two populations of P. lobata. Additionally, significant correlation was found between the morphological and genetic distances calculated from approximately 18,000 loci generated from restriction site-associated DNA sequencing. The unique morphological characters observed from the genetically differentiated population under environmental stress suggest that these characters may have adaptive values, but how such traits relate to fitness and how much plasticity they can exhibit remain to be determined by future studies. Relatively simple morphometric analyses used in our study can be useful in clarifying the existing ambiguity in skeletal architecture, thus contributing to resolving species issues in corals.

Understanding cold bias: Variable response of skeletal Sr/Ca to seawater pCO2 in acclimated massive Porites corals

PubMed Central

Cole, Catherine; Finch, Adrian; Hintz, Christopher; Hintz, Kenneth; Allison, Nicola

2016-01-01

Coral skeletal Sr/Ca is a palaeothermometer commonly used to produce high resolution seasonal sea surface temperature (SST) records and to investigate the amplitude and frequency of ENSO and interdecadal climate events. The proxy relationship is typically calibrated by matching seasonal SST and skeletal Sr/Ca maxima and minima in modern corals. Applying these calibrations to fossil corals assumes that the temperature sensitivity of skeletal Sr/Ca is conserved, despite substantial changes in seawater carbonate chemistry between the modern and glacial ocean. We present Sr/Ca analyses of 3 genotypes of massive Porites spp. corals (the genus most commonly used for palaeoclimate reconstruction), cultured under seawater pCO2 reflecting modern, future (year 2100) and last glacial maximum (LGM) conditions. Skeletal Sr/Ca is indistinguishable between duplicate colonies of the same genotype cultured under the same conditions, but varies significantly in response to seawater pCO2 in two genotypes of Porites lutea, whilst Porites murrayensis is unaffected. Within P. lutea, the response is not systematic: skeletal Sr/Ca increases significantly (by 2–4%) at high seawater pCO2 relative to modern in both genotypes, and also increases significantly (by 4%) at low seawater pCO2 in one genotype. This magnitude of variation equates to errors in reconstructed SST of up to −5 °C. PMID:27241795

Understanding cold bias: Variable response of skeletal Sr/Ca to seawater pCO2 in acclimated massive Porites corals.

PubMed

Cole, Catherine; Finch, Adrian; Hintz, Christopher; Hintz, Kenneth; Allison, Nicola

2016-05-31

Coral skeletal Sr/Ca is a palaeothermometer commonly used to produce high resolution seasonal sea surface temperature (SST) records and to investigate the amplitude and frequency of ENSO and interdecadal climate events. The proxy relationship is typically calibrated by matching seasonal SST and skeletal Sr/Ca maxima and minima in modern corals. Applying these calibrations to fossil corals assumes that the temperature sensitivity of skeletal Sr/Ca is conserved, despite substantial changes in seawater carbonate chemistry between the modern and glacial ocean. We present Sr/Ca analyses of 3 genotypes of massive Porites spp. corals (the genus most commonly used for palaeoclimate reconstruction), cultured under seawater pCO2 reflecting modern, future (year 2100) and last glacial maximum (LGM) conditions. Skeletal Sr/Ca is indistinguishable between duplicate colonies of the same genotype cultured under the same conditions, but varies significantly in response to seawater pCO2 in two genotypes of Porites lutea, whilst Porites murrayensis is unaffected. Within P. lutea, the response is not systematic: skeletal Sr/Ca increases significantly (by 2-4%) at high seawater pCO2 relative to modern in both genotypes, and also increases significantly (by 4%) at low seawater pCO2 in one genotype. This magnitude of variation equates to errors in reconstructed SST of up to -5 °C.

The relationship between the ratio of strontium to calcium and sea-surface temperature in a modern Porites astreoides coral: Implications for using P. astreoides as a paleoclimate archive

USGS Publications Warehouse

Tess E. Busch,; Flannery, Jennifer A.; Richey, Julie N.; Stathakopoulos, Anastasios

2015-11-13

An inverse relationship has been demonstrated between water temperature and the ratio of strontium to calcium (Sr/Ca) in coral aragonite for a number of Pacific species of the genus Porites. This empirically determined relationship has been used to reconstruct past sea-surface temperature (SST) from modern and Holocene age coral archives. A study was conducted to investigate this relationship for Porites astreoides to determine the potential for using these corals as a paleotemperature archive in the Caribbean and western tropical Atlantic Ocean. Skeletal aragonite from a P. astreoides colony growing offshore of the southeast coast of Florida was subsampled with a mean temporal resolution of 14 samples per year and analyzed for Sr/Ca. The resulting Sr/Ca time series yielded well-defined annual cycles that correspond to annual growth bands in the coral. Sr/Ca was regressed against a monthly SST record from C-MAN buoy station FWYF1 (located at Fowey Rocks, Florida), resulting in the following Sr/Ca-SST relationship: Sr/Ca = –0.040*SST + 10.128 (R = –0.77). A 10-year time series of Sr/Ca-derived SST yields annual cycles with a 10–12 degree Celsius seasonal amplitude, consistent with available local instrumental records. We conclude that Sr/Ca in Porites astreoides from the Caribbean/Atlantic region has high potential for developing subannually resolved modern and recent Holocene SST records.

Historical insights on growth rates of the reef-building corals Pavona gigantea and Porites panamensis from the Northeastern tropical Pacific.

PubMed

Tortolero-Langarica, J J A; Carricart-Ganivet, J P; Cupul-Magaña, A L; Rodríguez-Troncoso, A P

2017-12-01

Historical coral growth assessed by sclerochronology records provides an environmental retrospective and future perspective on the maintenance of coral-reef ecosystems. Three growth parameters, extension rate, skeletal density, and calcification rate were evaluated over the past two decade's interval (1988-2013) in different gender of two massive corals Pavona gigantea and Porites panamensis. The species P. gigantea calcified two-times faster (0.84 ± 0.29 g cm -2 yr -1 ) than P. panamensis (0.36 ± 0.15 g cm -2 yr -1 ); and male colonies presents13-58% higher calcification rates than females. Annual growth parameters do not show significant trends over the period 1988-2013, but significant, growth disruption associated with ENSO events. The data presented here suggest that P.gigantea and P.panamensis from the area have developed phenotypic plasticity to a wide range of environmental condition; the life history of both species is reflected in their calcification rates during both optimal and non-optimal conditions over the last two decades. Massive species develop denser structures that provide a permanent habitat to many marine species and contributes to the long-term maintenance of coral reef communities in the eastern tropical Pacific. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of Land Development on Holocene Porites Coral Calcification at Nagura Bay, Ishigaki Island, Japan

PubMed Central

Sowa, Kohki; Watanabe, Tsuyoshi; Kan, Hironobu; Yamano, Hiroya

2014-01-01

To evaluate the relationships between coral calcification, thermal stress, and sedimentation and eutrophication linked to human impact (hereafter referred to as “land development”) by river discharge, we analyzed growth characteristics in the context of a paleoenvironment that was reconstructed from geochemical signals in modern and fossil (1.2 cal kyr BP and 3.5 cal kyr BP, respectively) massive Porites corals from Nagura Bay (“Nagura”) and from modern Porites corals from the estuary of the Todoroki River, Shiraho Reef (“Todoroki”). Both sites are on Ishigaki Island, Japan, and Nagura is located approximately 12 km west of Todoroki. At Nagura, the individual corals provide time windows of 13 (modern), 10 (1.2 cal kyr BP), and 38 yr in length (3.5 cal kyr BP). Here, we present the coral annual calcification for Nagura and Todoroki, and (bi) monthly resolved records of Sr/Ca (a proxy of sea surface temperature (SST)) and Ba/Ca (a proxy of sedimentation and nutrients related to land development) for Nagura. At Nagura, the winter SST was cooler by 2.8°C in the 1.2 cal kyr BP, and the annual and winter SSTs in the 3.5 cal kyr BP were cooler by 2.6°C and 4.6°C, respectively. The annual periodicity of Ba/Ca in modern coral is linked to river discharge and is associated with land development including sugar cane cultivation. Modern coral calcification also has declined with SST warming and increasing Ba/Ca peaks in winter. However, calcification of fossil corals does not appear to have been influenced by variations in Sr/Ca and Ba/Ca. Modern coral growth characteristics at Nagura and Todoroki indicate that coral growth is both spatially and temporally influenced by river discharge and land development. At Nagura, our findings suggest that land development induces negative thermal sensitivity for calcification in winter due to sugar cane harvest, which is a specifically modern phenomenon. PMID:24586393

Health status of corals surrounding Kish Island, Persian Gulf.

PubMed

Alidoost Salimi, Mahsa; Mostafavi, Pargol Ghavam; Fatemi, Seyyed Mohammad; Aeby, Greta S

2017-03-30

Corals in the Persian Gulf exist in a harsh environment with extreme temperature and salinity fluctuations. Understanding the health of these hardy corals may prove useful for predicting the survival of other marine organisms facing the impacts of global climate change. In this study, the health state of corals was surveyed along belt transects at 4 sites on the east side of Kish Island, Iran. Corals had a patchy distribution, low colony densities and species diversity, and were dominated by Acropora, Porites, and Dipsastrea. We found chronic sedimentation on corals, a high prevalence of old partial mortality, abundant bioeroders, and overgrowth of corals by sponges and bryozoans. These are all signs indicating suboptimal environmental conditions for coral reefs. Four types of tissue loss lesions consistent with disease were found: Porites multi-focal chronic tissue loss, Porites peeling tissue loss, Porites focal chronic tissue loss, and Dipsastrea focal sub-acute tissue loss. Overall disease prevalence was 3.6% and there were significant differences in prevalence among the 3 most abundant coral genera. Acropora was numerically dominant within transects yet showed no signs of disease, whereas Porites had a 14% disease prevalence, indicating differential susceptibility to disease among genera. Other coral lesions included pigmentation response in Porites associated with algae invasion or boring organisms, sponge overgrowth, and mucus sheathing in Dipsastrea. The Persian Gulf region is understudied, and this represents one of the first quantitative surveys of coral health and disease on these reefs.

Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific

USGS Publications Warehouse

Aeby, Greta S.; Williams, Gareth J.; Franklin, Erik C.; Haapkyla, Jessica; Harvell, C. Drew; Neale, Stephen; Page, Cathie A.; Raymundo, Laurie; Vargas-Angel, Bernardo; Willis, Bette L.; Work, Thierry M.; Davy, Simon K.

2011-01-01

Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

Growth Anomalies on the Coral Genera Acropora and Porites Are Strongly Associated with Host Density and Human Population Size across the Indo-Pacific

PubMed Central

Franklin, Erik C.; Haapkyla, Jessica; Harvell, C. Drew; Neale, Stephen; Page, Cathie A.; Raymundo, Laurie; Vargas-Ángel, Bernardo; Willis, Bette L.; Work, Thierry M.; Davy, Simon K.

2011-01-01

Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment. PMID:21365011

Ecological Complexity of Coral Recruitment Processes: Effects of Invertebrate Herbivores on Coral Recruitment and Growth Depends Upon Substratum Properties and Coral Species

PubMed Central

Davies, Sarah W.; Matz, Mikhail V.; Vize, Peter D.

2013-01-01

Background The transition from planktonic planula to sessile adult corals occurs at low frequencies and post settlement mortality is extremely high. Herbivores promote settlement by reducing algal competition. This study investigates whether invertebrate herbivory might be modulated by other ecological factors such as substrata variations and coral species identity. Methodology/Principal Findings The experiment was conducted at the Flower Garden Banks, one of the few Atlantic reefs not experiencing considerable degradation. Tiles of differing texture and orientation were kept in bins surrounded by reef (24 m). Controls contained no herbivores while treatment bins contained urchins (Diadema antillarum) or herbivorous gastropods (Cerithium litteratum). Juvenile corals settling naturally were monitored by photography for 14 months to evaluate the effects of invertebrate herbivory and substratum properties. Herbivory reduced algae cover in urchin treatments. Two genera of brooding coral juveniles were observed, Agaricia and Porites, both of which are common but not dominant on adjacent reef. No broadcast spawning corals were observed on tiles. Overall, juveniles were more abundant in urchin treatments and on vertical, rough textured surfaces. Although more abundant, Agaricia juveniles were smaller in urchin treatments, presumably due to destructive overgrazing. Still, Agaricia growth increased with herbivory and substrata texture-orientation interactions were observed with reduced growth on rough tiles in control treatments and increased growth on vertical tiles in herbivore treatments. In contrast to Agaricia, Porites juveniles were larger on horizontal tiles, irrespective of herbivore treatment. Mortality was affected by substrata orientation with vertical surfaces increasing coral survival. Conclusions/Significance We further substantiate that invertebrate herbivores play major roles in early settlement processes of corals and highlight the need for deeper

Ocean acidification affects coral growth by reducing skeletal density.

PubMed

Mollica, Nathaniel R; Guo, Weifu; Cohen, Anne L; Huang, Kuo-Fang; Foster, Gavin L; Donald, Hannah K; Solow, Andrew R

2018-02-20

Ocean acidification (OA) is considered an important threat to coral reef ecosystems, because it reduces the availability of carbonate ions that reef-building corals need to produce their skeletons. However, while theory predicts that coral calcification rates decline as carbonate ion concentrations decrease, this prediction is not consistently borne out in laboratory manipulation experiments or in studies of corals inhabiting naturally low-pH reefs today. The skeletal growth of corals consists of two distinct processes: extension (upward growth) and densification (lateral thickening). Here, we show that skeletal density is directly sensitive to changes in seawater carbonate ion concentration and thus, to OA, whereas extension is not. We present a numerical model of Porites skeletal growth that links skeletal density with the external seawater environment via its influence on the chemistry of coral calcifying fluid. We validate the model using existing coral skeletal datasets from six Porites species collected across five reef sites and use this framework to project the impact of 21st century OA on Porites skeletal density across the global tropics. Our model predicts that OA alone will drive up to 20.3 ± 5.4% decline in the skeletal density of reef-building Porites corals.

First record of multi-species synchronous coral spawning from Malaysia.

PubMed

Chelliah, Alvin; Amar, Halimi Bin; Hyde, Julian; Yewdall, Katie; Steinberg, Peter D; Guest, James R

2015-01-01

Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites) participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta) exhibited highly synchronous spawning (100% of sampled colonies), two other common species (A. hyacinthus and A. digitifera) did not contain visible eggs in the majority of colonies sampled (i.e., <15% of colonies) in either April or October, suggesting that these species spawn at other times of the year. To the best of our knowledge, this is the first detailed documented observation of multi-species coral spawning from reefs in Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

First record of multi-species synchronous coral spawning from Malaysia

PubMed Central

Chelliah, Alvin; Amar, Halimi Bin; Hyde, Julian; Yewdall, Katie; Steinberg, Peter D.

2015-01-01

Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites) participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta) exhibited highly synchronous spawning (100% of sampled colonies), two other common species (A. hyacinthus and A. digitifera) did not contain visible eggs in the majority of colonies sampled (i.e., <15% of colonies) in either April or October, suggesting that these species spawn at other times of the year. To the best of our knowledge, this is the first detailed documented observation of multi-species coral spawning from reefs in Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia. PMID:25737817

Species-specific declines in the linear extension of branching corals at a subtropical reef, Lord Howe Island

NASA Astrophysics Data System (ADS)

Anderson, Kristen D.; Heron, Scott F.; Pratchett, Morgan S.

2015-06-01

Reef-building corals are extremely sensitive to changing temperature regimes, such that sustained increases in ocean temperatures are generally expected to have negative effects on coral growth and survivorship. At high-latitude reefs, however, projected increases in ocean temperature may actually increase coral growth (relaxing constraints imposed by cool winter temperatures), though this will depend upon on the rate and extent of declines in aragonite saturation, which is already much lower at high latitudes. This study quantified linear extension rates of six scleractinian corals, Acropora yongei, Isopora cuneata, Pocillopora damicornis, Porites heronensis, Seriatopora hystrix, and Stylophora pistillata, at Lord Howe Island in 2010/11. Contemporary growth rates were compared to equivalent data collected in 1994/95. There was marked interspecific variation in growth rates, with A. yongei growing almost twice the rate of all other species. Temporal changes in annual growth also varied among species. Growth rates of both A. yongei and Pocillopora damicornis were 30 % of that recorded in 1994/95. However, growth rates of Porites heronensis had not changed. Declines in the growth rates of these branching species may be attributable to declines in aragonite saturation or increases in summertime temperatures above limits for optimal growth, but either way it appears that climate change is having negative effects on corals, even at subtropical locations.

The Shifts of Diazotrophic Communities in Spring and Summer Associated with Coral Galaxea astreata, Pavona decussata, and Porites lutea.

PubMed

Zhang, Yanying; Yang, Qingsong; Ling, Juan; Van Nostrand, Joy D; Shi, Zhou; Zhou, Jizhong; Dong, Junde

2016-01-01

The coral holobiont often resides in oligotrophic waters; both coral cells and their symbiotic dinoflagellates possess ammonium assimilation enzymes and potentially benefit from the nitrogen fixation of coral-associated diazotrophs. However, the seasonal dynamics of coral-associated diazotrophs are not well characterized. Here, the seasonal variations of diazotrophic communities associated with three corals, Galaxea astreata, Pavona decussata , and Porites lutea , were studied using nifH gene amplicon pyrosequencing techniques. Our results revealed a great diversity of coral-associated diazotrophs. nifH sequences related to Alphaproteobacteria, Deltaproteobacteria , and Gammaproteobacteria were ubiquitous and dominant in all corals in two seasons. In contrast with the coral P. decussata , both G. astreata and P. lutea showed significant seasonal changes in the diazotrophic communities and nifH gene abundance. Variable diazotroph groups accounted for a range from 11 to 49% within individual coral samples. Most of the variable diazotrophic groups from P. decussata were species-specific, however, the majority of overlapping variable groups in G. astreata and P. lutea showed the same seasonal variation characteristics. Rhodopseudomonas palustris - and Gluconacetobacter diazotrophicus -affiliated sequences were relatively abundant in the summer, whereas a nifH sequence related to Halorhodospira halophila was relatively abundant in spring G. astreata and P. lutea . The seasonal variations of all diazotrophic communities were significantly correlated with the seasonal shifts of ammonium and nitrate, suggesting that diazotrophs play an important role in the nitrogen cycle of the coral holobiont.

The Shifts of Diazotrophic Communities in Spring and Summer Associated with Coral Galaxea astreata, Pavona decussata, and Porites lutea

PubMed Central

Zhang, Yanying; Yang, Qingsong; Ling, Juan; Van Nostrand, Joy D.; Shi, Zhou; Zhou, Jizhong; Dong, Junde

2016-01-01

The coral holobiont often resides in oligotrophic waters; both coral cells and their symbiotic dinoflagellates possess ammonium assimilation enzymes and potentially benefit from the nitrogen fixation of coral-associated diazotrophs. However, the seasonal dynamics of coral-associated diazotrophs are not well characterized. Here, the seasonal variations of diazotrophic communities associated with three corals, Galaxea astreata, Pavona decussata, and Porites lutea, were studied using nifH gene amplicon pyrosequencing techniques. Our results revealed a great diversity of coral-associated diazotrophs. nifH sequences related to Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria were ubiquitous and dominant in all corals in two seasons. In contrast with the coral P. decussata, both G. astreata and P. lutea showed significant seasonal changes in the diazotrophic communities and nifH gene abundance. Variable diazotroph groups accounted for a range from 11 to 49% within individual coral samples. Most of the variable diazotrophic groups from P. decussata were species-specific, however, the majority of overlapping variable groups in G. astreata and P. lutea showed the same seasonal variation characteristics. Rhodopseudomonas palustris- and Gluconacetobacter diazotrophicus-affiliated sequences were relatively abundant in the summer, whereas a nifH sequence related to Halorhodospira halophila was relatively abundant in spring G. astreata and P. lutea. The seasonal variations of all diazotrophic communities were significantly correlated with the seasonal shifts of ammonium and nitrate, suggesting that diazotrophs play an important role in the nitrogen cycle of the coral holobiont. PMID:27920768

Colony size as a species character in massive reef corals

NASA Astrophysics Data System (ADS)

Soong, Keryea

1993-07-01

In a study of seven massive, Caribbean corals, I have found major differences in reproductive behavior between species with large maximum colony sizes and species with smaller maximum colony sizes. Four species ( Diploria clivosa, D. strigosa, Montastrea cavernosa, Siderastrea siderea) which are large (<1000 cm2 in surface area) broadcast gametes during a short spawning season. Their puberty size is relatively large (>100 cm2, except M. cavernosa). In contrast, two small massive species (<100 cm2, Favia fragum and S. radians), and one medium-sized (100 1000 cm2, Porites astreoides) massive species, brood larvae during an extended season (year-round in Panama). The puberty size of the small species is only 2 4 cm2. Given these close associations between maximum colony sizes and a number of fundamental reproductive attributes, greater attention should be given to the colony size distributions of different species of reef corals in nature, since many important life history and population characters may be inferred.

Seasonal changes in bacterial communities associated with healthy and diseased Porites coral in southern Taiwan.

PubMed

Lin, Chorng-Horng; Chuang, Chih-Hsiang; Twan, Wen-Hung; Chiou, Shu-Fen; Wong, Tit-Yee; Liu, Jong-Kang; Kao, Chyuan-Yao; Kuo, Jimmy

2016-12-01

We compared the bacterial communities associated with healthy scleractinian coral Porites sp. with those associated with coral infected with pink spot syndrome harvested during summer and winter from waters off the coast of southern Taiwan. Members of the bacterial community associated with the coral were characterized by means of denaturing gradient gel electrophoresis (DGGE) of a short region of the 16S rRNA gene and clone library analysis. Of 5 different areas of the 16S rRNA gene, we demonstrated that the V3 hypervariable region is most suited to represent the coral-associated bacterial community. The DNA sequences of 26 distinct bands extracted from DGGE gels and 269 sequences of the 16S rRNA gene from clone libraries were determined. We found that the communities present in diseased coral were more heterogeneous than the bacterial communities of uninfected coral. In addition, bacterial communities associated with coral harvested in the summer were more diverse than those associated with coral collected in winter, regardless of the health status of the coral. Our study suggested that the compositions of coral-associated bacteria communities are complex, and the population of bacteria varies greatly between seasons and in coral of differing health status.

Diversity and distribution of Actinobacteria associated with reef coral Porites lutea

PubMed Central

Kuang, Weiqi; Li, Jie; Zhang, Si; Long, Lijuan

2015-01-01

Actinobacteria is a ubiquitous major group in coral holobiont. The diversity and spatial and temporal distribution of actinobacteria have been rarely documented. In this study, diversity of actinobacteria associated with mucus, tissue and skeleton of Porites lutea and in the surrounding seawater were examined every 3 months for 1 year on Luhuitou fringing reef. The population structures of the P. lutea-associated actinobacteria were analyzed using phylogenetic analysis of 16S rRNA gene clone libraries, which demonstrated highly diverse actinobacteria profiles in P. lutea. A total of 25 described families and 10 unnamed families were determined in the populations, and 12 genera were firstly detected in corals. The Actinobacteria diversity was significantly different between the P. lutea and the surrounding seawater. Only 10 OTUs were shared by the seawater and coral samples. Redundancy and hierarchical cluster analyses were performed to analyze the correlation between the variations of actinobacteria population within the divergent compartments of P. lutea, seasonal changes, and environmental factors. The actinobacteria communities in the same coral compartment tended to cluster together. Even so, an extremely small fraction of OTUs was common in all three P. lutea compartments. Analysis of the relationship between actinobacteria assemblages and the environmental parameters showed that several genera were closely related to specific environmental factors. This study highlights that coral-associated actinobacteria populations are highly diverse, and spatially structured within P. lutea, and they are distinct from which in the ambient seawater. PMID:26539166

Evidence of an inflammatory-like response in non-normally pigmented tissues of two scleractinian corals

PubMed Central

Palmer, Caroline V; Mydlarz, Laura D; Willis, Bette L

2008-01-01

Increasing evidence of links between climate change, anthropogenic stress and coral disease underscores the importance of understanding the mechanisms by which reef-building corals resist infection and recover from injury. Cellular inflammation and melanin-producing signalling pathway are two mechanisms employed by invertebrates to remove foreign organisms such as pathogens, but they have not been recorded previously in scleractinian corals. This study demonstrates the presence of the phenoloxidase (PO) activating melanin pathway in two species of coral, Acropora millepora and a massive species of Porites, which both develop local pigmentation in response to interactions with a variety of organisms. l-DOPA (3-(3,4-dihydroxyphenyl)-l-alanine) substrate-based enzyme activation assays demonstrated PO activity in healthy tissues of both species and upregulation in pigmented tissues of A. millepora. Histological staining conclusively identified the presence of melanin in Porites tissues. These results demonstrate that the PO pathway is active in both coral species. Moreover, the upregulation of PO activity in areas of non-normal pigmentation in A. millepora and increased melanin production in pigmented Porites tissues suggest the presence of a generalized defence response to localized stress. Interspecific differences in the usage of pathways involved in innate immunity may underlie the comparative success of massive Porites sp. as long-lived stress tolerators. PMID:18700208

Heavy metal contents in growth bands of Porites corals: record of anthropogenic and human developments from the Jordanian Gulf of Aqaba.

PubMed

Al-Rousan, Saber A; Al-Shloul, Rashid N; Al-Horani, Fuad A; Abu-Hilal, Ahmad H

2007-12-01

In order to assess pollutants and impact of environmental changes in the coastal region of the Jordanian Gulf of Aqaba, concentrations of six metals were traced through variations in 5 years growth bands sections of recent Porties coral skeleton. X-radiography showed annual growth band patterns extending back to the year 1925. Baseline metal concentrations in Porites corals were established using 35 years-long metal record from late Holocene coral (deposited in pristine environment) and coral from reef that is least exposed to pollution in the marine reserve in the Gulf of Aqaba. The skeleton samples of the collected corals were acid digested and analyzed for their Cd, Cu, Fe, Mn, Pb and Zn content using Flame Atomic Absorption Spectrophotometer (FAAS). All metal profiles (except Fe and Zn) recorded the same metal signature from recent coral (1925-2005) in which low steady baseline levels were displayed in growth bands older than 1965, similar to those obtained from fossil and unpolluted corals. Most metals showed dramatic increase (ranging from 17% to 300%) in growth band sections younger than 1965 suggesting an extensive contamination of the coastal area since the mid sixties. This date represents the beginning of a period that witnessed increasing coastal activities, constructions and urbanization. This has produced a significant reduction in coral skeletal extension rates. Results from this study strongly suggest that Porites corals have a high tendency to accumulate heavy metals in their skeletons and therefore can serve as proxy tools to monitor and record environmental pollution (bioindicators) in the Gulf of Aqaba.

Borehole density on the surface of living Porites corals as an indicator of sedimentation in Hong Kong.

PubMed

Xie, James Y; Wong, Jane C Y; Dumont, Clement P; Goodkin, Nathalie; Qiu, Jian-Wen

2016-07-15

Borehole density on the surface of Porites has been used as an indicator of water quality in the Great Barrier Reef. We assessed the relationship between borehole density on Porites and eight water quality parameters across 26 sites in Hong Kong. We found that total borehole densities on the surface of Porites at 16 of the studied sites were high (>1000individualsm(-2)), with polychaetes being the dominant bioeroders. Sedimentation rate was correlated positively with total borehole density and polychaete borehole density, with the latter relationship having a substantially higher correlation of determination. None of the environmental factors used were significantly correlated with bivalve borehole density. These results provide a baseline for assessing future changes in coral bioerosion in Hong Kong. This present study also indicates that polychaete boreholes can be used as a bioindicator of sedimentation in the South China Sea region where polychaetes are numerically dominant bioeroders. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mapping Prevalence and Incidence of Coral Disease in reef-building corals at two Natural Reserves of the Southwest Puerto Rico

NASA Astrophysics Data System (ADS)

Sanchez Viruet, I.; Irizarry-Soto, E.; Ruiz-Valentín, I.

2016-02-01

Coral diseases seems to be the main cause of coral reef decline in the Caribbean. Before the bleaching event of 2005, coral reefs in Puerto Rico were dominated by the reef-building taxa: Orbicella annularis, Porites astreoides, Montastrea cavernosa, Agaricia agaracites and Colpophyllia natans. After the event, live-coral cover significantly declined and more than 90% of the scleractinian corals in the U.S. Virgin Islands and Puerto Rico showed signals of thermal stressors. The prevalence of coral diseases in five reef-building coral (Orbicella annularis, Orbicella franksi, Orbicella faveolata, Porites porites and Pseudiploria strigosa) species was assessed by tagging, photographing, and mapping all diseased and healthy colonies within 10 permanent 40m2 band transects at each inshore and mid-shelf reefs of Belvedere and Punta Guaniquilla Natural Reserves using a random stratified sampling method. Maximum and perpendicular diameter was used to assess coral size using Coral Point Count with Excel Extension. Corals were classified into three size class populations (class I: 0-50cm, class II: 50-100cm and class III: >100 cm). Data was used to develop a GIS-based map containing coral species, size and disease presence. Preliminary results of the inshore area showed a higher disease prevalence in Belvedere natural reserve and for P. strigosa (17.1%) and O. annularis (9.3%). Frequency distribution analysis showed a dominance of O. faveolata at Punta Guaniquilla and Belvedere (127 and 88 individuals respectively). Size class I dominates the distribution of each species within the natural reserves with a higher disease prevalence. Future work include continue prevalence surveys of the outer reef shelf on both natural reserves, monitoring and GIS-based mapping of incidence and resilience through time. This study will help in the assessment of the status of the coral reef of the southwest insular platform.

Effects of Coralliophila violacea on tissue loss in the scleractinian corals Porites spp. depend on host response

USGS Publications Warehouse

Raymundo, L.; Work, Thierry M.; Miller, R.L.; Lozada-Misa, P.L.

2016-01-01

We investigated interactions between the corallivorous gastropod Coralliophila violacea and its preferred hosts Porites spp. Our objectives were to experimentally determine whether tissue loss could progress in Porites during or after Coralliophila predation on corals with and without tissue loss and to histologically document snail predation. In 64% of feeding scars, tissue regenerated within 3 wk, leaving no trace of predation. However, in roughly 28% of scars, lesions progressed to subacute tissue loss resembling white syndrome. In feeding experiments, scars from snails previously fed diseased tissue developed progressive tissue loss twice as frequently as scars from snails previously fed healthy tissue. Scars from previously healthy-fed snails were 3 times as likely to heal as those from previously diseased-fed snails. Histology revealed marked differences in host responses to snails; P. cylindrica manifested a robust inflammatory response with fewer secondary colonizing organisms such as algae, sponges, and helminths, whereas P. rus showed no evident inflammation and more secondary colonization. We conclude that lesion progression associated with Coralliophila may be associated with secondary colonization of coral tissues damaged by predator-induced trauma and necrosis. Importantly, variation at the cellular level should be considered when explaining interspecific differences in host responses in corals impacted by phenomena such as predation.

Species composition and morphologic variation of Porites in the Gulf of California

NASA Astrophysics Data System (ADS)

López-Pérez, R. A.

2013-09-01

Morphometric analysis of corallite calices confirmed that from the late Miocene to the Recent, four species of Porites have inhabited the Gulf of California: the extinct Porites carrizensis, the locally extirpated Porites lobata and the extant Porites sverdrupi and Porites panamensis. Furthermore, large-scale spatial and temporal phenotypic plasticity was observed in the dominant species P. panamensis. Canonical discriminant analysis and ANOVA demonstrated that the calice structures of P. panamensis experienced size reduction between the late Pleistocene and Recent. Similarly, PERMANOVA, regression and correlation analyses demonstrated that across the 800 km north to south in the gulf, P. panamensis populations displayed a similar reduction in calice structures. Based on correlation analysis with environmental data, these large spatial changes are likely related to changes in nutrient concentration and sea surface temperature. As such, the large-scale spatial and temporal phenotypic variation recorded in populations of P. panamensis in the Gulf of California is likely related to optimization of corallite performance (energy acquisition) within various environmental scenarios. These findings may have relevance to modern conservation efforts within this ecological dominant genus.

Strontium/calcium ratios in modern Porites corals from the Great Barrier Reef as a proxy for sea surface temperature: Calibration of the thermometer and monitoring of ENSO

NASA Astrophysics Data System (ADS)

Alibert, Chantal; McCulloch, Malcolm T.

1997-06-01

High-precision Sr/Ca ratios are reported for Porites corals from Davies Reef, at ˜19°S on the midshelf of the Great Barrier Reef, Australia. Skeletal growth parameters were also determined from coral slabs using X ray photographs and γ-densitometry measurements. A calibration of the Sr/Ca thermometer has been obtained, using in situ measured sea surface temperatures, which gives Sr/Ca × 10³ = 10.48 (±0.01) - 0.0615 (±0.0004) × T, whereT is in °C. This calibration applies to different species of Porites and a large range of annual extension and calcification rates, provided sampling follows a major growth axis. Biases of 1°-2°C have been observed in the low-density margins where growth is hampered by interfering fans of corallites. The analytical and the long-term reproducibility of Sr/Ca-derived temperatures are both better than ±0.3°C (2σ). Coral growth parameters such as the extension rate or density generally appear to respond to environmental changes such as rainfall but do not affect the Sr/Ca partitioning between coralline aragonite and seawater. No correlation has been found between calcification rate and Sr/Ca variations, consistent with Sr/Ca being mainly controlled by temperature. In the Great Barrier Reef, the interannual variability in SST is primarily related to the El Niño-Southern Oscillation phenomenon and is typically marked by a cold anomaly during the winter preceding the mature warm phase. Instrumental records show that the surface waters of the Coral Sea around 19°S have experienced a significant cooling associated with the El Niños of 1965, 1972, and 1982-1983 which the Porites corals record faithfully. The coral-derived temperatures for the period from 1965 to 1993 show an increase of 1.3°C, which has occurred mainly since 1979. This warming is larger in magnitude but consistent with the trend for the southern hemisphere land and marine temperature records, which shows an increase of around 0.4°C.

Annual coral bleaching and the long-term recovery capacity of coral

PubMed Central

Schoepf, Verena; Grottoli, Andréa G.; Levas, Stephen J.; Aschaffenburg, Matthew D.; Baumann, Justin H.; Matsui, Yohei; Warner, Mark E.

2015-01-01

Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able to recover between annual bleaching events. Using a combined tank and field experiment, we simulated annual bleaching by exposing three Caribbean coral species (Porites divaricata, Porites astreoides and Orbicella faveolata) to elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of annual bleaching stress on chlorophyll a, energy reserves, calcification, and tissue C and N isotopes was assessed immediately after the second bleaching and after both short- and long-term recovery on the reef (1.5 and 11 months, respectively). While P. divaricata and O. faveolata were able to recover from repeat bleaching within 1 year, P. astreoides experienced cumulative damage that prevented full recovery within this time frame, suggesting that repeat bleaching had diminished its recovery capacity. Specifically, P. astreoides was not able to recover protein and carbohydrate concentrations. As energy reserves promote bleaching resistance, failure to recover from annual bleaching within 1 year will likely result in the future demise of heat-sensitive coral species. PMID:26582020

SYMBIODINIUM ISOLATES FROM STONY CORAL: ISOLATION, GROWTH CHARACTERISTICS AND EFFECTS OF UV IRRADIATION

EPA Science Inventory

Symbiodinium spp. Isolates from Stony Coral: Isolation, Growth Characteristics and Effects of UV Irradiation (Abstract). J. Phycol. 37(3):42-43.

Symbiodinium species were isolated from Montipora capitata, Acropora palmata and two field samples of Porites porites. Cultures ...

Annual coral bleaching and the long-term recovery capacity of coral.

PubMed

Schoepf, Verena; Grottoli, Andréa G; Levas, Stephen J; Aschaffenburg, Matthew D; Baumann, Justin H; Matsui, Yohei; Warner, Mark E

2015-11-22

Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able to recover between annual bleaching events. Using a combined tank and field experiment, we simulated annual bleaching by exposing three Caribbean coral species (Porites divaricata, Porites astreoides and Orbicella faveolata) to elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of annual bleaching stress on chlorophyll a, energy reserves, calcification, and tissue C and N isotopes was assessed immediately after the second bleaching and after both short- and long-term recovery on the reef (1.5 and 11 months, respectively). While P. divaricata and O. faveolata were able to recover from repeat bleaching within 1 year, P. astreoides experienced cumulative damage that prevented full recovery within this time frame, suggesting that repeat bleaching had diminished its recovery capacity. Specifically, P. astreoides was not able to recover protein and carbohydrate concentrations. As energy reserves promote bleaching resistance, failure to recover from annual bleaching within 1 year will likely result in the future demise of heat-sensitive coral species. © 2015 The Author(s).

Transplantation of storm-generated coral fragments to enhance Caribbean coral reefs: A successful method but not a solution

USGS Publications Warehouse

Garrison, Virginia H.; Ward, Greg A.

2012-01-01

In response to dramatic losses of reef-building corals and ongoing lack of recovery, a small-scale coral transplant project was initiated in the Caribbean (U.S. Virgin Islands) in 1999 and was followed for 12 years. The primary objectives were to (1) identify a source of coral colonies for transplantation that would not result in damage to reefs, (2) test the feasibility of transplanting storm-generated coral fragments, and (3) develop a simple, inexpensive method for transplanting fragments that could be conducted by the local community.  The ultimate goal was to enhance abundance of threatened reef-building species on local reefs.  Storm-produced coral fragments of two threatened reef-building species [Acropora palmata and A. cervicornis (Acroporidae)] and another fast-growing species [Porites porites (Poritidae)] were collected from environments hostile to coral fragment survival and transplanted to degraded reefs.  Inert nylon cable ties were used to attach transplanted coral fragments to dead coral substrate.  Survival of 75 reference colonies and 60 transplants was assessed over 12 years. Only 9% of colonies were alive after 12 years: no A. cervicornis; 3% of A. palmata transplants and 18% of reference colonies; and 13% of P. porites transplants and 7% of reference colonies. Mortality rates for all species were high and were similar for transplant and reference colonies. Physical dislodgement resulted in the loss of 56% of colonies, whereas 35% died in place.  Only A. palmata showed a difference between transplant and reference colony survival and that was in the first year only.  Location was a factor in survival only for A. palmata reference colonies and after year 10.  Even though the tested methods and concepts were proven effective in the field over the 12-year study, they do not present a solution. No coral conservation strategy will be effective until underlying intrinsic and/or extrinsic factors driving high mortality rates are

detrimentally affects tissue regeneration of Red Sea corals

NASA Astrophysics Data System (ADS)

Horwitz, Rael; Fine, Maoz

2014-09-01

Ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) is threatening the future of coral reef ecosystems. Mounting experimental evidence suggests that OA negatively impacts fundamental life functions of scleractinian corals, including growth and sexual reproduction. Although regeneration is regarded as a chief life function in scleractinian corals and essential to maintain the colony's integrity, the effect of OA on regeneration processes has not yet been investigated. To evaluate the effects of OA on regeneration, the common Indo-Pacific corals Porites sp., Favia favus, Acropora eurystoma, and Stylophora pistillata were inflicted with lesions (314-350 mm2, depending on species) and incubated in different pCO2: (1) ambient seawater (400 µatm, pH 8.1), (2) intermediate (1,800 µatm, pH 7.6), and (3) high (4,000 µatm, pH 7.3) for extended periods of time (60-120 d). While all coral species after 60 d had significantly higher tissue regeneration in ambient conditions as compared to the intermediate and high treatments, reduction in regeneration rate was more pronounced in the slow-growing massive Porites sp. and F. favus than the relatively fast-growing, branching S. pistillata and A. eurystoma. This coincided with reduced tissue biomass of Porites sp., F. favus, and A. eurystoma in higher pCO2, but not in S. pistillata. Porites sp., F. favus, and S. pistillata also experienced a decrease in Symbiodinium density in higher pCO2, while in A. eurystoma there was no change. We hypothesize that a lowered regenerative capacity under elevated pCO2 may be related to resource trade-offs, energy cost of acid/base regulation, and/or decrease in total energy budget. This is the first study to demonstrate that elevated pCO2 could have a compounding influence on coral regeneration following injury, potentially affecting the capacity of reef corals to recover following physical disturbance.

Implications of coral harvest and transplantation on reefs in northwestern Dominica.

PubMed

Bruckner, Andrew W; Borneman, Eric H

2010-10-01

In June, 2002, the government of Dominica requested assistance in evaluating the coral culture and transplantation activities being undertaken by Oceanographic Institute of Dominica (OID), a coral farm culturing both western Atlantic and Indo-Pacific corals for restoration and commercial sales. We assessed the culture facilities of OID, the condition of reefs, potential impacts of coral collection and benefits of coral transplantation. Coral reefs (9 reefs, 3-20 m depth) were characterized by 35 species of scleractinian corals and a live coral cover of 8-35%. Early colonizing, brooders such as Porites astreoides (14.8% of all corals), P. porites (14.8%), Meandrina meandrites (14.7%) and Agaricia agaricites (9.1%) were the most abundant corals, but colonies were mostly small (mean = 25 cm diameter). Montastraea annularis (complex) was the other dominant taxa (20.8% of all corals) and colonies were larger (mean = 70 cm). Corals (pooled species) were missing an average of 20% of their tissue, with a mean of 1.4% recent mortality. Coral diseases affected 6.4% of all colonies, with the highest prevalence at Cabrits West (11.0%), Douglas Bay (12.2%) and Coconut Outer reef (20.7%). White plague and yellow band disease were causing the greatest loss of tissue, especially among M. annularis (complex), with localized impacts from corallivores, overgrowth by macroalgae, storm damage and sedimentation. While the reefs appeared to be undergoing substantial decline, restoration efforts by OlD were unlikely to promote recovery. No Pacific species were identified at OID restoration sites, yet species chosen for transplantation with highest survival included short-lived brooders (Agaricia and Porites) that were abundant in restoration sites, as well as non-reef builders (Palythoa and Erythropodium) that monopolize substrates and overgrow corals. The species of highest value for restoration (massive broadcast spawners) showed low survivorship and unrestored populations of these

The effect of species and colony size on the bleaching response of reef-building corals in the Florida Keys during the 2005 mass bleaching event

NASA Astrophysics Data System (ADS)

Brandt, M. E.

2009-12-01

Understanding the variation in coral bleaching response is necessary for making accurate predictions of population changes and the future state of reefs in a climate of increasing thermal stress events. Individual coral colonies, belonging to inshore patch reef communities of the Florida Keys, were followed through the 2005 mass bleaching event. Overall, coral bleaching patterns followed an index of accumulated thermal stress more closely than in situ temperature measurements. Eight coral species ( Colpophyllia natans, Diploria strigosa, Montastraea cavernosa, M. faveolata, Porites astreoides, P. porites, Siderastrea siderea, and Stephanocoenia intersepta), representing >90% of the coral colonies studied, experienced intense levels of bleaching, but responses varied. Bleaching differed significantly among species: Colpophyllia natans and Diploria strigosa were most susceptible to thermal stress, while Stephanocoenia intersepta was the most tolerant. For colonies of C. natans, M. faveolata, and S. siderea, larger colonies experienced more extensive bleaching than smaller colonies. The inshore patch reef communities of the Florida Keys have historically been dominated by large colonies of Montastraea sp. and Colpophyllia natans. These results provide evidence that colony-level differences can affect bleaching susceptibility in this habitat and suggest that the impact of future thermal stress events may be biased toward larger colonies of dominant reef-building species. Predicted increases in the frequency of mass bleaching and subsequent mortality may therefore result in significant structural shifts of these ecologically important communities.

Quantification of total and particulate dimethylsulfoniopropionate (DMSP) in five Bermudian coral species across a depth gradient

NASA Astrophysics Data System (ADS)

Yost, D. M.; Jones, R.; Rowe, C. L.; Mitchelmore, Carys Louise

2012-06-01

The symbiotic dinoflagellate microalgae of corals ( Symbiodinium spp.) contain high concentrations of dimethylsulfoniopropionate (DMSP), a multifunctional metabolite commonly found in many species of marine algae and dinoflagellates. A photoprotective antioxidant function for DMSP and its breakdown products has often been inferred in algae, but its role(s) in the coral-algal symbiosis remains elusive. To examine potential correlations between environmental and physiological parameters and DMSP, total DMSP (DMSPt, from the host coral and zooxanthellae), particulate DMSP (DMSPp, from the zooxanthellae only), coral surface area, and total protein, as well as zooxanthellae density, chlorophyll concentration, cell volume and genotype (i.e., clade) were measured in five coral species from the Diploria- Montastraea- Porites species complex in Bermuda along a depth gradient of 4, 12, 18, and 24 m. DMSPt concentrations were consistently greater than DMSPp concentrations in all species suggesting the possible translocation of DMSP from symbiont to host. D. labyrinthiformis was notably different from the other corals examined, showing DMSPp and DMSPt increases (per coral surface area or tissue biomass) with increasing water depth. However, overall, there were no consistent depth-related patterns in DMSPp and DMSPt concentrations. Further research, investigating dimethylsulfide (DMS), dimethylsulfoxide, and acrylate levels and DMSP-lyase activity in correlation with other biomarker endpoints that have been shown to be depth (i.e., temperature and light) responsive are needed to substantiate the significance of these findings.

Impacts of ocean acidification on coral calcification: experimental results from a field study around submarine springs

NASA Astrophysics Data System (ADS)

Paytan, A.; Martínez Fernández, A.; Varona, N.

2017-12-01

Reef building corals are facing the effects of ocean acidification on calcification. Atmospheric carbon dioxide dissolves into the oceans and decreases the pH and the availability of carbonate ions in seawater. Carbonate ions are used by calcifying corals to create their calcium carbonate exoskeletons in the form of aragonite. As carbon dioxide emissions increase, corals may have problems precipitating their aragonite skeleton in low carbonate saturation seawater. Natural submarine groundwater springs discharge low pH seawater into the Caribbean Sea, in the Yucatan Peninsula (Mexico). These submarine springs serve as a natural laboratory to study the effects of low aragonite saturation water on coral growth. Here we show the skeletal growth parameters of three coral species under an in situ ocean acidification experiment. Nubbins of Porites porites, Porites astreoides and Siderastrea radians were collected at low pH springs and control sites and reciprocally transplanted into a low pH discharge site and into a control site not impacted by discharge. After two years, the nubbins were collected and linear extension, density and calcification rates were analyzed. Preliminary results show that coral skeleton density is significantly lower in corals transplanted into the low pH than in corals transplanted in control sites. Infaunal bioerosion is present in corals deployed at low pH sites. In contrast, linear extension and hence calcification rates do not seem to show a significant difference among sites. However, the coral species show diverse calcification responses under ocean acidification conditions, suggesting some species may be more vulnerable than others to a change in water chemistry.

A novel method for the transport and analysis of genetic material from polyps and zooxanthellae of scleractinian corals.

PubMed

Crabbe, M James C

2003-08-29

We have developed a new simple method for transport, storage, and analysis of genetic material from the corals Agaricia agaricites, Dendrogyra cylindrica, Eusmilia ancora, Meandrina meandrites, Montastrea annularis, Porites astreoides, Porites furcata, Porites porites, and Siderastrea siderea at room temperature. All species yielded sufficient DNA from a single FTA card (19 microg-43 ng) for subsequent PCR amplification of both coral and zooxanthellar DNA. The D1 and D2 variable region of the large subunit rRNA gene (LSUrDNA) was amplified from the DNA of P. furcata and S. siderea by PCR. Electrophoresis yielded two major DNA bands: an 800-base pair (bp) DNA, which represented the coral ribosomal RNA (rRNA) gene, and a 600-bp DNA, which represented the zooxanthellar srRNA gene. Extraction of DNA from the bands yielded between 290 microg total DNA (S. siderea coral DNA) and 9 microg total DNA (P. furcata zooxanthellar DNA). The ability to transport and store genetic material from scleractinian corals without resort to laboratory facilities in the field allows for the molecular study of a far wider range and variety of coral sites than have been studied to date.

Dissepiments, density bands and signatures of thermal stress in Porites skeletons

NASA Astrophysics Data System (ADS)

DeCarlo, Thomas M.; Cohen, Anne L.

2017-09-01

The skeletons of many reef-building corals are accreted with rhythmic structural patterns that serve as valuable sclerochronometers. Annual high- and low-density band couplets, visible in X-radiographs or computed tomography scans, are used to construct age models for paleoclimate reconstructions and to track variability in coral growth over time. In some corals, discrete, anomalously high-density bands, called "stress bands," preserve information about coral bleaching. However, the mechanisms underlying the formation of coral skeletal density banding remain unclear. Dissepiments—thin, horizontal sheets of calcium carbonate accreted by the coral to support the living polyp—play a key role in the upward growth of the colony. Here, we first conducted a vital staining experiment to test whether dissepiments were accreted with lunar periodicity in Porites coral skeleton, as previously hypothesized. Over 6, 15, and 21 months, dissepiments consistently formed in a 1:1 ratio to the number of full moons elapsed over each study period. We measured dissepiment spacing to reconstruct multiple years of monthly skeletal extension rates in two Porites colonies from Palmyra Atoll and in another from Palau that bleached in 1998 under anomalously high sea temperatures. Spacing between successive dissepiments exhibited strong seasonality in corals containing annual density bands, with narrow (wide) spacing associated with high (low) density, respectively. A high-density "stress band" accreted during the 1998 bleaching event was associated with anomalously low dissepiment spacing and missed dissepiments, implying that thermal stress disrupts skeletal extension. Further, uranium/calcium ratios increased within stress bands, indicating a reduction in the carbonate ion concentration of the coral's calcifying fluid under stress. Our study verifies the lunar periodicity of dissepiments, provides a mechanistic basis for the formation of annual density bands in Porites, and reveals the

Evidence of host-associated divergence from coral-eating snails (genus Coralliophila) in the Coral Triangle

NASA Astrophysics Data System (ADS)

Simmonds, Sara E.; Chou, Vincent; Cheng, Samantha H.; Rachmawati, Rita; Calumpong, Hilconida P.; Ngurah Mahardika, G.; Barber, Paul H.

2018-06-01

We studied how host-associations and geography shape the genetic structure of sister species of marine snails Coralliophila radula (A. Adams, 1853) and C. violacea (Kiener, 1836). These obligate ectoparasites prey upon corals and are sympatric throughout much of their ranges in coral reefs of the tropical and subtropical Indo-Pacific. We tested for population genetic structure of snails in relation to geography and their host corals using mtDNA (COI) sequences in minimum spanning trees and AMOVAs. We also examined the evolutionary relationships of their Porites host coral species using maximum likelihood trees of RAD-seq (restriction site-associated DNA sequencing) loci mapped to a reference transcriptome. A maximum likelihood tree of host corals revealed three distinct clades. Coralliophila radula showed a pronounced genetic break across the Sunda Shelf ( Φ CT = 0.735) but exhibited no genetic structure with respect to host. C. violacea exhibited significant geographic structure ( Φ CT = 0.427), with divergence among Hawaiian populations, the Coral Triangle and the Indian Ocean. Notably, C. violacea showed evidence of ecological divergence; two lineages were associated with different groups of host coral species, one widespread found at all sites, and the other restricted to the Coral Triangle. Sympatric populations of C. violacea found on different suites of coral species were highly divergent ( Φ CT = 0.561, d = 5.13%), suggesting that symbiotic relationships may contribute to lineage diversification in the Coral Triangle.

Microbial aggregates within tissues infect a diversity of corals throughout the Indo-Pacific

USGS Publications Warehouse

Work, Thierry M.; Aeby, Greta S.

2014-01-01

Coral reefs are highly diverse ecosystems where symbioses play a pivotal role. Corals contain cell-associated microbial aggregates (CAMA), yet little is known about how widespread they are among coral species or the nature of the symbiotic relationship. Using histology, we found CAMA within 24 species of corals from 6 genera from Hawaii, American Samoa, Palmyra, Johnston Atoll, Guam, and Australia. Prevalence (%) of infection varied among coral genera: Acropora, Porites, and Pocillopora were commonly infected whereas Montipora were not. Acropora from the Western Pacific were significantly more likely to be infected with CAMA than those from the Central Pacific, whereas the reverse was true for Porites. Compared with apparently healthy colonies, tissues from diseased colonies were significantly more likely to have both surface and basal body walls infected. The close association of CAMA with host cells in numerous species of apparently healthy corals and lack of associated cell pathology reveals an intimate agent-host association. Furthermore, CAMA are Gram negative and in some corals may be related to chlamydia or rickettsia. We propose that CAMA in adult corals are facultative secondary symbionts that could play an important ecological role in some dominant coral genera in the Indo-Pacific. CAMA are important in the life histories of other animals, and more work is needed to understand their role in the distribution, evolution, physiology, and immunology of reef corals.

Identification and prevalence of coral diseases on three Western Indian Ocean coral reefs.

PubMed

Séré, Mathieu G; Chabanet, Pascale; Turquet, Jean; Quod, Jean-Pascal; Schleyer, Michael H

2015-06-03

Coral diseases have caused a substantial decline in the biodiversity and abundance of reef-building corals. To date, more than 30 distinct diseases of scleractinian corals have been reported, which cause progressive tissue loss and/or affect coral growth, reproductive capacity, recruitment, species diversity and the abundance of reef-associated organisms. While coral disease research has increased over the last 4 decades, very little is known about coral diseases in the Western Indian Ocean. Surveys conducted at multiple sites in Reunion, South Africa and Mayotte between August 2010 and June 2012 revealed the presence of 6 main coral diseases: black band disease (BBD), white syndrome (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). Overall, disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%) and Mayotte (2.7 ± 0.3%). Across locations, Acropora and Porites were the genera most susceptible to disease. Spatial variability was detected in both Reunion and South Africa, with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in 2 diseases: the prevalence of BBD and WS was higher in summer than winter. This was the first study to investigate the ecology of coral diseases, providing both qualitative and quantitative data, on Western Indian Ocean reefs, and surveys should be expanded to confirm these patterns.

Use of scleractinian corals to indicate marine pollution in the northern Gulf of Aqaba, Jordan.

PubMed

Barakat, S A; Al-Rousan, S; Al-Trabeen, M S

2015-02-01

The actual and fatal concentrations of selected heavy metals, including cadmium, cobalt, copper, lead, nickel, and zinc in corals from the Gulf of Aqaba were determined. Several living coral samples of different species (e.g., Porites) were collected from shallow depths (of about 5 m) at a number of sites along the Jordanian Gulf of Aqaba coast. The coral samples were collected using either a pneumatic diamond drill corer (for Porites) or a hammer and chisel (for other branched species). Some of the corals that had been collected were analyzed for heavy metals using atomic absorption spectrometry, and other samples were used in incubation experiments. The heavy metal concentrations were determined separately in the coral skeleton and the tissue layer. Heavy metal concentrations have not previously been determined in corals from the Gulf of Aqaba. We conclude that corals are suitable for use as proxy tools for assessing environmental pollution (i.e., they are bioindicators) in the Gulf of Aqaba and the Red Sea. Therefore, this study provides useful information on the degree of heavy metal contamination in the study area.

Differential thermal response within inshore vs. offshore congeneric scleractinian coral species in Palau.

NASA Astrophysics Data System (ADS)

Hoadley, K. D.; Lewis, A.; Wham, D.; Pettay, D. T.; Kemp, D.; Warner, M.; Lajeunesse, T.

2016-02-01

The rock island reef habitats of Palau are an ideal location to study climate change effects to reefs, as corals there are exposed to average temperature and pCO2 conditions well above levels experienced at offshore reef locations. We examined the response of 6 coral species, Acropora muricata, Goniastrea sp, Porities rus, Cyphastrea sp, Porites cylindrical and Pachyseris sp, from both rock island and offshore habitats to high temperature (32 Celsius) for 15 days. With the exception of P. rus and P. cylindrica which harbored Symbiodinium C15 at both locations, other rock island corals harbored the thermally tolerant species Symbiodinium trenchii, whereas offshore colonies harbored clade C symbionts. A total of 15 separate host and symbiont physiological variables were utilized to assess thermal acclimation/stress response within each host/symbiont combination. Differences in photophysiology, algal cell volume and biochemical composition were observed for Symbiodinium trenchii within different host species, reflecting the importance of the host organism in mitigating the symbiont response. Similarly, the host thermal response was also dependent on symbiont type, with greater reductions in symbiont density occurring within the offshore colonies. Overall, prior exposure to warmer temperatures, elevated nutrient and pCO2 conditions, along with association with more robust symbionts allowed rock island corals to exhibit greater thermal tolerance toward high temperature. Importantly, the results herein for Symbiodinium trenchii physiological plasticity and thermal mitigation provides useful insight into the potential of scleractinian corals to acclimatize under future climate change scenarios.

Variation in larval properties of the Atlantic brooding coral Porites astreoides between different reef sites in Bermuda

NASA Astrophysics Data System (ADS)

de Putron, Samantha J.; Lawson, Julia M.; White, Kascia Q. L.; Costa, Matthew T.; Geronimus, Miriam V. B.; MacCarthy, Anne

2017-06-01

Recent research has documented phenotypic differences among larvae released from corals with a brooding reproductive mode, both among species and within broods from a single species. We studied larvae released from the common Atlantic coral Porites astreoides in Bermuda to further evaluate phenotypic variability. Inter-site differences were investigated in larvae from conspecifics at a rim and patch reef site. Larvae were collected daily for one lunar cycle from several colonies per site each year over 5 yr. Larval volume varied with reef site of origin, with colonies from the rim reef site producing larger larvae than colonies from the patch reef site. This inter-site variation in larval size could not be explained by corallite size and may be a response to different environmental conditions at the sites. Larvae from both reef sites also varied in size depending on lunar day of release over 4 yr of study. Regardless of site of origin, smaller larvae were released earlier in the lunar cycle. Over 1 yr of study, lipid and zooxanthellae content and settlement success after 48 h covaried with larval size. However, there may be a trade-off between larger larvae and reduced fecundity. Overall, larvae released from colonies from the rim reef site were larger and had greater settlement success than those from colonies from the patch reef site. This study documents larval phenotypic variability and a distinct inter-site difference in larval ecology among conspecifics within the same geographic area, which may have implications for recruitment success, population dynamics, and resilience.

Vibrational spectroscopic characterization of growth bands in Porites coral from South China Sea

NASA Astrophysics Data System (ADS)

Song, Yinxian; Yu, Kefu; Ayoko, Godwin A.; Frost, Ray L.; Shi, Qi; Feng, Yuexing; Zhao, Jianxin

2013-08-01

A series of samples from different growth bands of Porites coral skeleton were studied using Raman, infrared reflectance methods. The Raman spectra proved that skeleton samples from different growth bands have the same mineral phase as aragonite, but a band at 133 cm-1 for the top layer shows a transition from ˜120 cm-1 for vaterite to ˜141 cm-1 for aragonite. It is inferred that the vaterite should be the precursor of aragonite of coral skeleton. The positional shift in the infrared spectra of the skeleton samples from growth bands correlate significantly to their minor elements (Li, Mg, Sr, Mn, Fe and U) contents. Mg, Sr and U especially have significant negative correlations with the positions of the antisymmetric stretching band ν3 at ˜1469 cm-1. And Li shows a high negative correlation with ν2 band (˜855 cm-1), while Sr and Mn show similar negative correlation with ν4 band (˜712 cm-1). And Mn also shows a negative correlation with ν1 band (˜1082 cm-1). A significantly negative correlation is observed for U with ν1 + ν4 band (˜1786 cm-1). However, Fe shows positive correlation with ν1, ν2, ν3, ν4 and ν1 + ν4 bands shifts, especially a significant correlation with ν1 band (˜1082 cm-1). New insights into the characteristics of coral at different growth bands of skeleton are given in present work.

Stress response of two coral species in the Kavaratti atoll of the Lakshadweep Archipelago, India

NASA Astrophysics Data System (ADS)

Harithsa, Shashank; Raghukumar, Chandralata; Dalal, S. G.

2005-11-01

Frequent occurrences of coral bleaching and the ensuing damage to coral reefs have generated interest in documenting stress responses that precede bleaching. The objective of this study was to assess and compare physiological changes in healthy, semi-bleached and totally bleached colonies of two coral species, Porites lutea and Acropora formosa, during a natural bleaching event in the Lakshadweep Archipelago in the Arabian Sea to determine the traits that will be useful in the diagnosis of coral health. In April 2002, three “health conditions” were observed as “appearing healthy,” “semi-bleached” and “bleached” specimens for two dominant and co-occurring coral species in these islands. Changes in the pigment composition, zooxanthellae density (ZD), mitotic index (MI) of zooxanthellae, RNA/DNA ratios and protein profile in the two coral species showing different levels of bleaching in the field were compared to address the hypothesis of no difference in health condition between species and bleaching status. The loss in chlorophyll (chl) a, chl c and ZD in the transitional stage of semi-bleaching in the branched coral A. formosa was 80, 75 and 80%, respectively. The losses were much less in the massive coral P. lutea, being 20, 50 and 25%, respectively. The decrease in zooxanthellar density and chl a was accompanied by an increased MI of zooxanthellae and RNA/DNA ratios in both the species. There was an increase in accumulation of lipofuscin granules in partially bleached P. lutea tissue, which is an indication of cellular senescence. Multivariate statistical analyses showed that colonies of P. lutea ranked in different health conditions differed significantly in chl a, chl c, ZD, RNA/DNA ratios, and protein concentrations, whereas in A. formosa chl a, chl c, chl a/ c, phaeopigments and MI contributed to the variance between health conditions.

Gene expression under chronic heat stress in populations of the mustard hill coral (Porites astreoides) from different thermal environments.

PubMed

Kenkel, C D; Meyer, E; Matz, M V

2013-08-01

Recent evidence suggests that corals can acclimatize or adapt to local stress factors through differential regulation of their gene expression. Profiling gene expression in corals from diverse environments can elucidate the physiological processes that may be responsible for maximizing coral fitness in their natural habitat and lead to a better understanding of the coral's capacity to survive the effects of global climate change. In an accompanying paper, we show that Porites astreoides from thermally different reef habitats exhibit distinct physiological responses when exposed to 6 weeks of chronic temperature stress in a common garden experiment. Here, we describe expression profiles obtained from the same corals for a panel of 9 previously reported and 10 novel candidate stress response genes identified in a pilot RNA-Seq experiment. The strongest expression change was observed in a novel candidate gene potentially involved in calcification, SLC26, a member of the solute carrier family 26 anion exchangers, which was down-regulated by 92-fold in bleached corals relative to controls. The most notable signature of divergence between coral populations was constitutive up-regulation of metabolic genes in corals from the warmer inshore location, including the gluconeogenesis enzymes pyruvate carboxylase and phosphoenolpyruvate carboxykinase and the lipid beta-oxidation enzyme acyl-CoA dehydrogenase. Our observations highlight several molecular pathways that were not previously implicated in the coral stress response and suggest that host management of energy budgets might play an adaptive role in holobiont thermotolerance. © 2013 John Wiley & Sons Ltd.

The Role of Maternal Nutrition on Oocyte Size and Quality, with Respect to Early Larval Development in The Coral-Eating Starfish, Acanthaster planci.

PubMed

Caballes, Ciemon Frank; Pratchett, Morgan S; Kerr, Alexander M; Rivera-Posada, Jairo A

2016-01-01

Variation in local environmental conditions can have pronounced effects on the population structure and dynamics of marine organisms. Previous studies on crown-of-thorns starfish, Acanthaster planci, have primarily focused on effects of water quality and nutrient availability on larval growth and survival, while the role of maternal nutrition on reproduction and larval development has been overlooked. To examine the effects of maternal nutrition on oocyte size and early larval development in A. planci, we pre-conditioned females for 60 days on alternative diets of preferred coral prey (Acropora abrotanoides) versus non-preferred coral prey (Porites rus) and compared resulting gametes and progeny to those produced by females that were starved over the same period. Females fed ad libitum with Acropora increased in weight, produced heavier gonads and produced larger oocytes compared to Porites-fed and starved females. Fed starfish (regardless of whether it was Acropora or Porites) produced bigger larvae with larger stomachs and had a higher frequency of normal larvae that reached the late bipinnaria / early brachiolaria stage compared to starved starfish. Females on Acropora diet also produced a higher proportion of larvae that progressed to more advanced stages faster compared to Porites-fed starfish, which progressed faster than starved starfish. These results suggest that maternal provisioning can have important consequences for the quality and quantity of progeny. Because food quality (coral community structure) and quantity (coral abundance) varies widely among reef locations and habitats, local variation in maternal nutrition of A. planci is likely to moderate reproductive success and may explain temporal and spatial fluctuations in abundance of this species.

Herbivory versus corallivory: are parrotfish good or bad for Caribbean coral reefs?

NASA Astrophysics Data System (ADS)

Mumby, Peter J.

2009-09-01

With coral cover in decline on many Caribbean reefs, any process of coral mortality is of potential concern. While sparisomid parrotfishes are major grazers of Caribbean reefs and help control algal blooms, the fact that they also undertake corallivory has prompted some to question the rationale for their conservation. Here the weight of evidence for beneficial effects of parrotfishes, in terms of reducing algal cover and facilitating demographic processes in corals, and the deleterious effects of parrotfishes in terms of causing coral mortality and chronic stress, are reviewed. While elevated parrotfish density will likely increase the predation rate upon juvenile corals, the net effect appears to be positive in enhancing coral recruitment through removal of macroalgal competitors. Parrotfish corallivory can cause modest partial colony mortality in the most intensively grazed species of Montastraea but the generation and healing of bite scars appear to be in near equilibrium, even when coral cover is low. Whole colony mortality in adult corals can lead to complete exclusion of some delicate, lagoonal species of Porites from forereef environments but is only reported for one reef species ( Porites astreoides), for one habitat (backreef), and with uncertain incidence (though likely <<10%). No deleterious effects of predation on coral growth or fecundity have been reported, though recovery of zooxanthellae after bleaching events may be retarded. The balance of evidence to date finds strong support for the herbivory role of parrotfishes in facilitating coral recruitment, growth, and fecundity. In contrast, no net deleterious effects of corallivory have been reported for reef corals. Corallivory is unlikely to constrain overall coral cover but contraints upon dwindling populations of the Montastraea annularis species complex are feasible and the role of parrotfishes as a vector of coral disease requires evaluation. However, any assertion that conservation practices

Induction of Larval Settlement in the Reef Coral Porites astreoides by a Cultivated Marine Roseobacter Strain.

PubMed

Sharp, K H; Sneed, J M; Ritchie, K B; Mcdaniel, L; Paul, V J

2015-04-01

Successful larval settlement and recruitment by corals is critical for the survival of coral reef ecosystems. Several closely related strains of γ-proteobacteria have been identified as cues for coral larval settlement, but the inductive properties of other bacterial taxa naturally occurring in reef ecosystems have not yet been explored. In this study, we assayed bacterial strains representing taxonomic groups consistently detected in corals for their ability to influence larval settlement in the coral Porites astreoides. We identified one α-proteobacterial strain, Roseivivax sp. 46E8, which significantly increased larval settlement in P. astreoides. Logarithmic growth phase (log phase) cell cultures of Roseivivax sp. 46E8 and filtrates (0.22μm) from log phase Roseivivax sp. 46E8 cultures significantly increased settlement, suggesting that an extracellular settlement factor is produced during active growth phase. Filtrates from log phase cultures of two other bacterial isolates, Marinobacter sp. 46E3, and Cytophaga sp. 46B6, also significantly increased settlement, but the cell cultures themselves did not. Monospecific biofilms of the three strains did not result in significant increases in larval settlement. Organic and aqueous/methanol extracts of Roseivivax sp. 46E8 cultures did not affect larval settlement. Examination of filtrates from cell cultures showed that Roseivivax sp. 46E8 spontaneously generated virus-like particles in log and stationary phase growth. Though the mechanism of settlement enhancement by Roseivivax sp. 46E8 is not yet elucidated, our findings point to a new aspect of coral-Roseobacter interactions that should be further investigated, especially in naturally occurring, complex microbial biofilms on reef surfaces. © 2015 Marine Biological Laboratory.

The effects of ultraviolet radiation on growth and bleaching in three species of Hawaiian coral

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodman, G.D.

1990-01-09

Long term exposure to ultraviolet radiation is harmful to many organisms, including hermatypic corals, which obtain much of their nutrition from photosynthetic zooxanthellae. Therefore, increased UV radiation from atmospheric ozone depletion could inhibit growth of such corals. Moreover, coral bleaching, which has been attributed to loss of pigment and/or expulsion of zooxanthellae, may be a specific response to UV light. Does UV-A reduce skeletal growth or influence population density and pigment content of zooxanthellae In addition, do zooxanthellae migrate to shaded areas of the colony to avoid ultraviolet light Using alizarin red stain and suitable filters, I compared the stainmore » and suitable filters, I compared the effects of UV-A (320-400nm) and full-spectrum UV (280-400nm) on the skeletal growth of two Hawaiian corals, Montipora verrucosa, Pocillopora damicornis, in situ. In the perforate corals, M. Verrucosa and Porites compressa, I measured concentration of zooxanthellae and their chlorophyll content to quantify bleaching in response to UV light. Reduction in skeletal growth by the two corals in response to different ranges of UV light appears to be species specific. Bleaching by UV appears to be characterized by an initial loss of pigment followed by the expulsion and migration of the zooxanthellae to shaded areas of the colony. Differences in tolerance and adaptation to decreasing ozone levels and increasing UV light should confer a competitive advantage on various species and morphologies of reef-building corals.« less

a Preliminary Characterisation of SYMBIODINIUM Diversity in Some Common Corals from Singapore

NASA Astrophysics Data System (ADS)

Isa Tanzil, Jani Thuaibah; Ng, Abigayle Pek Kaye; Tey, Yi Qing; Tan, Beverly Hsin Yi; Yun, Eric Yao; Huang, Danwei

The symbiosis between corals and Symbiodinium dinoflagellates is considered a major driver of the distribution and health of reefs worldwide. This study investigated the genetic identities and diversity of Symbiodinium in seven coral species (Porites lutea, Porites lobata, Acropora millepora, Merulina ampliata, Diploastrea heliopora, Pachyseris speciosa, Pocillopora acuta) from three shallow reefs around Singapore (Kusu Island, Pulau Tekukor, Pulau Satumu). Analyses of 31 colonies using denaturing gradient gel electrophoresis of the nuclear internal transcribed spacer region indicated the dominance of C and D Symbiodinium clades. The latter clade was the predominant symbiont in Pachyseris speciosa collected from Pulau Tekukor but those sampled from Pulau Satumu hosted C27, providing evidence for variable symbiosis in this species. The prevalence of the D clade - noted for their stress tolerance (e.g. to elevated temperatures and sedimentation) - in three of seven coral species examined could underlie the importance of this particular symbiotic relationship for the persistence of Singapore’s impacted reefs. Further characterisation of Symbiodinium communities may provide insights into corals’ response to stress and their bleaching patterns in the future.

Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean: Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea.

PubMed

García-Arredondo, Alejandro; Rojas-Molina, Alejandra; Ibarra-Alvarado, César; Lazcano-Pérez, Fernando; Arreguín-Espinosa, Roberto; Sánchez-Rodríguez, Judith

2016-01-01

Scleractinian corals (stony corals) are the most abundant reef-forming cnidarians found in coral reefs throughout the world. Despite their abundance and ecological importance, information about the diversity of their toxins and their biological activities is very scarce. In this study, the chemical composition and the biological activities of the aqueous extracts of Pseudodiploria strigosa , Porites astreoides and Siderastrea siderea , three scleractinian corals from the Mexican Caribbean, have been assessed for the first time. Toxicity of the extracts was assessed in crickets; the presence of cytolysins was detected by the hemolysis assay; the vasoconstrictor activity was determined by the isolated rat aortic ring assay; the nociceptive activity was evaluated by the formalin test. The presence of phospholipases A 2 (PLA 2 ), serine proteases, and hyaluronidases was determined by enzymatic methods. Low-molecular-weight fractions were obtained by gel filtration chromatography and ultrafiltration. Extracts from the three species were toxic to crickets, induced hemolysis in human and rat erythrocytes, produced vasoconstriction on isolated rat aortic rings, and presented phospholipase A 2 and serine-protease activity. Despite the fact that these corals are not considered to be harmless to humans, the extracts generated significant nociceptive responses. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of the low-molecular-weight fractions revealed the presence of peptides within a mass range of 3000 to 6000 Da. These fractions were toxic to crickets and two of them induced a transitory vasoconstrictor effect on isolated rat aortic rings. This study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.

Relative sensitivity of five Hawaiian coral species to high temperature under high-pCO2 conditions

NASA Astrophysics Data System (ADS)

Bahr, Keisha D.; Jokiel, Paul L.; Rodgers, Ku'ulei S.

2016-06-01

Coral reef ecosystems are presently undergoing decline due to anthropogenic climate change. The chief detrimental factors are increased temperature and increased pCO2. The purpose of this study was to evaluate the effect of these two stressors operating independently and in unison on the biological response of common Hawaiian reef corals. Manipulative experiments were performed using five species ( Porites compressa, Pocillopora damicornis, Fungia scutaria, Montipora capitata, and Leptastrea purpurea) in a continuous-flow mesocosm system under natural sunlight conditions. Corals were grown together as a community under treatments of high temperature (2 °C above normal maximum summer temperature), high pCO2 (twice present-day conditions), and with both factors acting in unison. Control corals were grown under present-day pCO2 and at normal summer temperatures. Leptastrea purpurea proved to be an extremely hardy coral. No change in calcification or mortality occurred under treatments of high temperature, high pCO2, or combined high temperature-high pCO2. The remaining four species showed reduced calcification in the high-temperature treatment. Two species ( L. purpurea and M. capitata) showed no response to increased pCO2. Also, high pCO2 ameliorated the negative effect of high temperature on the calcification rates of P. damicornis. Mortality was driven primarily by high temperature, with a negative synergistic effect in P. compressa only in the high-pCO2-high-temperature treatment. Results support the observation that biological response to temperature and pCO2 elevation is highly species-specific, so generalizations based on response of a single species might not apply to a diverse and complex coral reef community.

Spatial refugia mediate juvenile coral survival during coral-predator interactions

NASA Astrophysics Data System (ADS)

Gallagher, Clare; Doropoulos, Christopher

2017-03-01

Coral recruitment and juvenile growth are essential processes for coral population maintenance and recovery. A growing body of research has evaluated the influence of reef microstructure on coral settlement and post-settlement survival, showing that physical refugia enhance recruitment. These studies have evaluated coral recruit morality from competition with macroalgae and indirect predation by grazing organisms, but the impact of direct predation by corallivorous piscine species on juvenile corals and how this interacts with reef microstructure is relatively unknown. This study examined whether refugia provided by micro-crevices enhance juvenile coral survival from corallivory. Juvenile corals from two different functional groups, the slow-growing massive Porites lobata and fast-growing branching Pocillopora damicornis, with average nubbin sizes of 1.4 cm × 0.3 cm and 0.5 cm × 1.0 cm (diameter × height), respectively, were attached to experimental tiles using small (1.44 cm3) and large (8.0 cm3) crevice sizes and were monitored for 29 d on a forereef in Palau. Full crevices (four sided) enhanced coral survival compared to exposed microhabitats in both coral taxa, but crevice size did not alter survival rates. Corallivores targeted recruits within crevices regardless of crevice size; dominant predators included small triggerfish (Balistidae), butterflyfish ( Chaetodon), and wrasse ( Cheilinus). Overall, Pocillopora suffered much higher rates of mortality than Porites. All Pocillopora were consumed by day 8 of the experiment, but mortality was significantly delayed in full crevices compared to exposed and partial crevice (three sided) microhabitats. In contrast, Por. lobata located in all microhabitats survived the entire experiment up to 29 d, with high survival in full (>90%) and partial crevices (70%), but only 28% survival in exposed microhabitats. These findings show the importance of crevices as spatial refugia from predators for juvenile corals and

The Role of Maternal Nutrition on Oocyte Size and Quality, with Respect to Early Larval Development in The Coral-Eating Starfish, Acanthaster planci

PubMed Central

Pratchett, Morgan S.; Kerr, Alexander M.; Rivera-Posada, Jairo A.

2016-01-01

Variation in local environmental conditions can have pronounced effects on the population structure and dynamics of marine organisms. Previous studies on crown-of-thorns starfish, Acanthaster planci, have primarily focused on effects of water quality and nutrient availability on larval growth and survival, while the role of maternal nutrition on reproduction and larval development has been overlooked. To examine the effects of maternal nutrition on oocyte size and early larval development in A. planci, we pre-conditioned females for 60 days on alternative diets of preferred coral prey (Acropora abrotanoides) versus non-preferred coral prey (Porites rus) and compared resulting gametes and progeny to those produced by females that were starved over the same period. Females fed ad libitum with Acropora increased in weight, produced heavier gonads and produced larger oocytes compared to Porites-fed and starved females. Fed starfish (regardless of whether it was Acropora or Porites) produced bigger larvae with larger stomachs and had a higher frequency of normal larvae that reached the late bipinnaria / early brachiolaria stage compared to starved starfish. Females on Acropora diet also produced a higher proportion of larvae that progressed to more advanced stages faster compared to Porites-fed starfish, which progressed faster than starved starfish. These results suggest that maternal provisioning can have important consequences for the quality and quantity of progeny. Because food quality (coral community structure) and quantity (coral abundance) varies widely among reef locations and habitats, local variation in maternal nutrition of A. planci is likely to moderate reproductive success and may explain temporal and spatial fluctuations in abundance of this species. PMID:27327627

Bio-prospecting of coral (Porites lutea) mucus associated bacteria, Palk Bay reefs, Southeast coast of India.

PubMed

Ahila, N K; Prakash, S; Manikandan, B; Ravindran, J; Prabhu, N M; Kannapiran, E

2017-12-01

Coral mucus is one of the key localization in the coral holobiont, as this serves as an energy rich substrate for a wide range of abundant, diverse and multifunctional microbiota. However, very little is known about the functional role of bacterial communities in their associations with corals. In the present study, a total of 48 isolates were obtained from Porites lutea wherein the genus of Bacillus sp. and Vibrio sp. were predominant. Bio-prospecting the coral mucus revealed the existence of (10.42%) antagonistic bacteria against the tested bacterial pathogens. Molecular taxonomy (16S rRNA) proved the identity of these antagonistic bacteria belong to Enterobacter cloacae (CM1), Bacillus subtilis (CM2), Bacillus sp. (CM11) and Bacillus marisflavi (CM12). The secondary screening emphasized that the ethyl acetate extract of B. subtilis showed strong antagonistic effect, followed by the chloroform extract of E. cloacae and ethyl acetate extract of B. marisflavi. The antagonistic activity was statistically confirmed by Principal Component Analysis and Hierarchical Cluster Analysis. The privileged coral mucus associated bacterial (CMAB) solvent extracts inhibited the bacterial pathogens at 100 μg/ml (MIC) and ceased the growth at 200 μg/ml (MBC). The hemolytic and brine shrimp lethality assays disclosed the non-toxic nature of solvent extracts of CMAB. Altogether, the present investigation brought out the diversity of bacteria associated with the mucus of P. lutea. In addition, bio-prospecting corroborated the CMAB as the potential source of pharmacologically important bioactive compounds against a wide range of bacterial pathogens. Copyright © 2017 Elsevier Ltd. All rights reserved.

Link between sewage-derived nitrogen pollution and coral disease severity in Guam.

PubMed

Redding, Jamey E; Myers-Miller, Roxanna L; Baker, David M; Fogel, Marilyn; Raymundo, Laurie J; Kim, Kiho

2013-08-15

The goals of this study were to evaluate the contribution of sewage-derived N to reef flat communities in Guam and to assess the impact of N inputs on coral disease. We used stable isotope analysis of macroalgae and a soft coral, sampled bimonthly, as a proxy for N dynamics, and surveyed Porites spp., a dominant coral taxon on Guam's reefs, for white syndrome disease severity. Results showed a strong influence of sewage-derived N in nearshore waters, with δ(15)N values varying as a function of species sampled, site, and sampling date. Increases in sewage-derived N correlated significantly with increases in the severity of disease among Porites spp., with δ(15)N values accounting for more than 48% of the variation in changes in disease severity. The anticipated military realignment and related population increase in Guam are expected to lead to increased white syndrome infections and other coral diseases. Copyright © 2013 Elsevier Ltd. All rights reserved.

Long distance dispersal and vertical gene flow in the Caribbean brooding coral Porites astreoides

PubMed Central

Serrano, Xaymara M.; Baums, Iliana B.; Smith, Tyler B.; Jones, Ross J.; Shearer, Tonya L.; Baker, Andrew C.

2016-01-01

To date, most assessments of coral connectivity have emphasized long-distance horizontal dispersal of propagules from one shallow reef to another. The extent of vertical connectivity, however, remains largely understudied. Here, we used newly-developed and existing DNA microsatellite loci for the brooding coral Porites astreoides to assess patterns of horizontal and vertical connectivity in 590 colonies collected from three depth zones (≤10 m, 15–20 m and ≥25 m) at sites in Florida, Bermuda and the U.S. Virgin Islands (USVI). We also tested whether maternal transmission of algal symbionts (Symbiodinium spp.) might limit effective vertical connectivity. Overall, shallow P. astreoides exhibited high gene flow between Florida and USVI, but limited gene flow between these locations and Bermuda. In contrast, there was significant genetic differentiation by depth in Florida (Upper Keys, Lower Keys and Dry Tortugas), but not in Bermuda or USVI, despite strong patterns of depth zonation in algal symbionts at two of these locations. Together, these findings suggest that P. astreoides is effective at dispersing both horizontally and vertically despite its brooding reproductive mode and maternal transmission of algal symbionts. In addition, these findings might help explain the ecological success reported for P. astreoides in the Caribbean in recent decades. PMID:26899614

Red sea corals as biomonitors of trace metal pollution.

PubMed

Hanna, R G; Muir, G L

1990-05-01

Red Sea corals have been found to be biomonitors of trace metal pollution. A comparative study was undertaken on three species from a polluted area near a desalination plant at Jeddah (Saudi Arabia) and from an unpolluted area. The results show that corals take-up trace elements from their aquatic environment and thereby act to record changes in the composition of that environment. Variations in the composition of skeletons and soft tissues of corals have been correlated with changes in sea water composition. Three coral species, Porites lutea, Goniastrea retiformis and Pocillopora verrucosa have been analysed for Hg, Cu, Zn, Pb, Mn, Fe, Ni, Cd, V, Al, Cr, Mg, B, Ca, and Sr in both skeletal and soft tissues. Results show that corals in the polluted areas have significantly higher concentrations of trace elements compared to that of corals from unpolluted areas.

Sex-associated variations in coral skeletal oxygen and carbon isotopic composition of Porites panamensis in the southern Gulf of California

NASA Astrophysics Data System (ADS)

Cabral-Tena, R. A.; Sánchez, A.; Reyes-Bonilla, H.; Ruvalcaba-Díaz, A. H.; Balart, E. F.

2015-11-01

Coral δ18O variations are used as a proxy for changes in near sea surface temperature and seawater isotope composition. Skeletal δ13C of coral is frequently used as a proxy for solar radiation because most of its variability is controlled by an interrelationship between three processes: photosynthesis, respiration, and feeding. Coral growth rate is known to influence the δ18O and δ13C isotope record to a lesser extent. Recent published data show differences in growth parameters between female and male coral; thus, skeletal δ18O and δ13C are hypothesized to be different in each sex. To assess this difference, this study describes changes in the skeletal δ18O and δ13C record of four female and six male Porites panamensis coral collected in Bahía de La Paz, whose growth bands spanned 12 years. The isotopic data were compared to SST, precipitation, PAR, chlorophyll a, and skeletal growth parameters. Porites panamensis is a known gonochoric brooder whose growth parameters are different in females and males. Splitting the data by sexes explained 81 and 93 % of the differences of δ18O, and of δ13C, respectively, in the isotope record between colonies. Both isotope records were different between sexes. δ18O was higher in female colonies than in male colonies, with a 0.31 ‰ difference; δ13C was lower in female colonies, with a 0.28 ‰ difference. A difference in the skeletal δ18O implies an error in SST estimates of ≈ 1.0 °C to ≈ 2.6 °C. The δ18O records showed a seasonal pattern that corresponded to SST, with low correlation coefficients (-0.45, -0.32), and gentle slopes (0.09 ‰ °C-1, 0.10 ‰ °C-1) of the δ18O-SST relation. Seasonal variation in coral δ18O represents only 52.37 and 35.66 % of the SST cycle; 29.72 and 38.53 % can be attributed to δ18O variability in seawater. δ13C data did not correlate with any of the environmental variables; therefore, variations in skeletal δ13C appear to be driven mainly by metabolic effects. Our

Host shift and speciation in a coral-feeding nudibranch

PubMed Central

Faucci, Anuschka; Toonen, Robert J; Hadfield, Michael G

2006-01-01

While the role of host preference in ecological speciation has been investigated extensively in terrestrial systems, very little is known in marine environments. Host preference combined with mate choice on the preferred host can lead to population subdivision and adaptation leading to host shifts. We use a phylogenetic approach based on two mitochondrial genetic markers to disentangle the taxonomic status and to investigate the role of host specificity in the speciation of the nudibranch genus Phestilla (Gastropoda, Opisthobranchia) from Guam, Palau and Hawaii. Species of the genus Phestilla complete their life cycle almost entirely on their specific host coral (species of Porites, Goniopora and Tubastrea). They reproduce on their host coral and their planktonic larvae require a host-specific chemical cue to metamorphose and settle onto their host. The phylogenetic trees of the combined cytochrome oxidase I and ribosomal 16S gene sequences clarify the relationship among species of Phestilla identifying most of the nominal species as monophyletic clades. We found a possible case of host shift from Porites to Goniopora and Tubastrea in sympatric Phestilla spp. This represents one of the first documented cases of host shift as a mechanism underlying speciation in a marine invertebrate. Furthermore, we found highly divergent clades within Phestilla sp. 1 and Phestilla minor (8.1–11.1%), suggesting cryptic speciation. The presence of a strong phylogenetic signal for the coral host confirms that the tight link between species of Phestilla and their host coral probably played an important role in speciation within this genus. PMID:17134995

The effects of habitat on coral bleaching responses in Kenya.

PubMed

Grimsditch, Gabriel; Mwaura, Jelvas M; Kilonzo, Joseph; Amiyo, Nassir

2010-06-01

This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa. These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali), it was found that coral recovery occurred more quickly in the protected area than in the non-protected area.

Summer spawning of Porites lutea from north-western Australia

NASA Astrophysics Data System (ADS)

Stoddart, C. W.; Stoddart, J. A.; Blakeway, D. R.

2012-09-01

Most coral species off Australia's west coast spawn in the austral autumn (March-April), with a few species also spawning in the southern spring or early summer (November-December). This is the reverse timing to spawning recorded off Australia's east coast. Porites lutea, a gonochoric broadcast spawner that is common on Australia's west coast, is shown here to spawn in the months of November or December, as it does on Australia's east coast. Spawning occurred between 2 and 5 nights after full moon, with the majority of spawning activity on night 3. Gametes developed over three to four months with rapid development in the last two weeks before spawning. Zooxanthellae were typically observed in mature oocytes, only a week before spawning so their presence may provide a useful indicator of imminent spawning.

Diversity and stability of coral endolithic microbial communities at a naturally high pCO2 reef.

PubMed

Marcelino, Vanessa Rossetto; Morrow, Kathleen M; van Oppen, Madeleine J H; Bourne, David G; Verbruggen, Heroen

2017-10-01

The health and functioning of reef-building corals is dependent on a balanced association with prokaryotic and eukaryotic microbes. The coral skeleton harbours numerous endolithic microbes, but their diversity, ecological roles and responses to environmental stress, including ocean acidification (OA), are not well characterized. This study tests whether pH affects the diversity and structure of prokaryotic and eukaryotic algal communities associated with skeletons of Porites spp. using targeted amplicon (16S rRNA gene, UPA and tufA) sequencing. We found that the composition of endolithic communities in the massive coral Porites spp. inhabiting a naturally high pCO 2 reef (avg. pCO 2 811 μatm) is not significantly different from corals inhabiting reference sites (avg. pCO 2 357 μatm), suggesting that these microbiomes are less disturbed by OA than previously thought. Possible explanations may be that the endolithic microhabitat is highly homeostatic or that the endolithic micro-organisms are well adapted to a wide pH range. Some of the microbial taxa identified include nitrogen-fixing bacteria (Rhizobiales and cyanobacteria), algicidal bacteria in the phylum Bacteroidetes, symbiotic bacteria in the family Endozoicomoniaceae, and endolithic green algae, considered the major microbial agent of reef bioerosion. Additionally, we test whether host species has an effect on the endolithic community structure. We show that the endolithic community of massive Porites spp. is substantially different and more diverse than that found in skeletons of the branching species Seriatopora hystrix and Pocillopora damicornis. This study reveals highly diverse and structured microbial communities in Porites spp. skeletons that are possibly resilient to OA. © 2017 John Wiley & Sons Ltd.

Reduced calcification and lack of acclimatization by coral colonies growing in areas of persistent natural acidification.

PubMed

Crook, Elizabeth D; Cohen, Anne L; Rebolledo-Vieyra, Mario; Hernandez, Laura; Paytan, Adina

2013-07-02

As the surface ocean equilibrates with rising atmospheric CO2, the pH of surface seawater is decreasing with potentially negative impacts on coral calcification. A critical question is whether corals will be able to adapt or acclimate to these changes in seawater chemistry. We use high precision CT scanning of skeletal cores of Porites astreoides, an important Caribbean reef-building coral, to show that calcification rates decrease significantly along a natural gradient in pH and aragonite saturation (Ωarag). This decrease is accompanied by an increase in skeletal erosion and predation by boring organisms. The degree of sensitivity to reduced Ωarag measured on our field corals is consistent with that exhibited by the same species in laboratory CO2 manipulation experiments. We conclude that the Porites corals at our field site were not able to acclimatize enough to prevent the impacts of local ocean acidification on their skeletal growth and development, despite spending their entire lifespan in low pH, low Ωarag seawater.

Skeleton microstructure of Porites lutea in Kondang Merak, Malang, East Java

NASA Astrophysics Data System (ADS)

Luthfi, Oktiyas Muzaky; Sontodipoero, R. M. Agung M. Rizqon; Isdianto, Andik; Setyohadi, Daduk; Jauhari, Alfan; Januarsa, I. Nyoman

2017-11-01

Research on coral microstructure in Indonesia, especially in East Java is rarely done. Therefore, this study aims to examine the shape of Aragonite Crystal coral Porites lutea in Pantai Kondak Merak, East Java, especially in 1998 which is the time of El Nino and has a global impact on coral growth. The shape of the aragonite crystal on the reef can be seen using the Scanning Electron Microscopy-Energy Dispersion X-Ray (SEM - EDX). Based on the coral aragonite crystal form, the increasing temperature in 1998 was not proven to have a devastating effect on the growth of corals of Pantai Kondang Merak. In contrast, the temperature at this site should support corals in order to grow rapidly, but there are other environmental factors that ultimately inhibit the growth of the coral.

Early development of zooxanthella-containing eggs of the corals Porites cylindrica and Montipora digitata: The endodermal localization of zooxanthellae.

PubMed

Hirose, Mamiko; Hidaka, Michio

2006-10-01

We studied the early development of zooxanthellae-containing eggs of the scleractinian corals Porites cylindrica and Montipora digitata to elucidate how zooxanthellae become localized to the endoderm of planulae during the course of development. In both species, zooxanthellae were distributed evenly in the oocytes and delivered almost equally to the blastomeres during cleavage. In P. cylindrica, gastrulation occurred via delamination or ingression, and blastomeres containing zooxanthellae dropped into the blastocoel during gastrulation. Thus, zooxanthellae were restricted to the endodermal cells at the gastrula or early planula stage in P. cylindrica. In M. digitata, gastrulation occurred by a combination of invagination and epiboly to form a somewhat concave gastrula. Zooxanthellae were present in both endodermal and ectodermal cells of early planulae, but they disappeared from the ectoderm as the planulae matured. In our previous study on two species of Pocillopora, we found that zooxanthellae were localized in eggs as well as in embryos, and that blastomeres containing zooxanthellae later dropped into the blastocoel to become restricted to the endoderm (Hirose et al., 2000). The timing and mechanism of zooxanthella localization and types of gastrulation differed among species belonging to the three genera. These results suggest that zooxanthella localization in the embryos reflects the timing of the determination of presumptive endoderm cells and/or specificity of zooxanthellae toward presumptive endoderm cells.

Protein expression and genetic structure of the coral Porites lobata in an environmentally extreme Samoan back reef: Does host genotype limit phenotypic plasticity?

USGS Publications Warehouse

Barshis, D.J.; Stillman, J.H.; Gates, R.D.; Toonen, R.J.; Smith, L.W.; Birkeland, C.

2010-01-01

The degree to which coral reef ecosystems will be impacted by global climate change depends on regional and local differences in corals' susceptibility and resilience to environmental stressors. Here, we present data from a reciprocal transplant experiment using the common reef building coral Porites lobata between a highly fluctuating back reef environment that reaches stressful daily extremes, and a more stable, neighbouring forereef. Protein biomarker analyses assessing physiological contributions to stress resistance showed evidence for both fixed and environmental influence on biomarker response. Fixed influences were strongest for ubiquitin-conjugated proteins with consistently higher levels found in back reef source colonies both pre and post-transplant when compared with their forereef conspecifics. Additionally, genetic comparisons of back reef and forereef populations revealed significant population structure of both the nuclear ribosomal and mitochondrial genomes of the coral host (FST = 0.146 P < 0.0001, FST = 0.335 P < 0.0001 for rDNA and mtDNA, respectively), whereas algal endosymbiont populations were genetically indistinguishable between the two sites. We propose that the genotype of the coral host may drive limitations to the physiological responses of these corals when faced with new environmental conditions. This result is important in understanding genotypic and environmental interactions in the coral algal symbiosis and how corals may respond to future environmental changes. ?? 2010 Blackwell Publishing Ltd.

Reconstructing skeletal fiber arrangement and growth mode in the coral Porites lutea (Cnidaria, Scleractinia): a confocal Raman microscopy study

NASA Astrophysics Data System (ADS)

Wall, M.; Nehrke, G.

2012-11-01

Confocal Raman microscopy (CRM) mapping was used to investigate the microstructural arrangement and organic matrix distribution within the skeleton of the coral Porites lutea. Relative changes in the crystallographic orientation of crystals within the fibrous fan-system could be mapped, without the need to prepare thin sections, as required if this information is obtained by polarized light microscopy. Simultaneously, incremental growth lines can be visualized without the necessity of etching and hence alteration of sample surface. Using these methods two types of growth lines could be identified: one corresponds to the well-known incremental growth layers, whereas the second type of growth lines resemble denticle finger-like structures (most likely traces of former spines or skeletal surfaces). We hypothesize that these lines represent the outer skeletal surface before another growth cycle of elongation, infilling and thickening of skeletal areas continues. We show that CRM mapping with high spatial resolution can significantly improve our understanding of the micro-structural arrangement and growth patterns in coral skeletons.

Abundance and composition of juvenile corals reveals divergent trajectories for coral assemblages across the United Arab Emirates.

PubMed

Pratchett, Morgan S; Baird, Andrew H; Bauman, Andrew G; Burt, John A

2017-01-30

Marked shifts in the composition of coral assemblages are occurring at many locations, but it is unknown whether these are permanent shifts reinforced by patterns of population replenishment. This study examined the composition of juvenile coral assemblages across the United Arab Emirates (UAE). Densities of juvenile corals varied significantly among locations, but were highest where coral cover was highest. Juvenile coral assemblages within the Persian Gulf were dominated by Porites, while no Acropora were recorded. We expect therefore, continued declines in Acropora abundance, while observed dominance of Porites is likely to persist. In the Oman Sea, Pocillopora was the dominant juvenile coral, with Acropora and Stylophora also recorded. This study shows that taxonomic differences in replenishment are reinforcing temporal shifts in coral composition within the southern Persian Gulf, but not in the Oman Sea. Differences in environmental conditions and disturbance regimes likely explain the divergent responses between regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differential larval settlement responses of Porites astreoides and Acropora palmata in the presence of the green alga Halimeda opuntia

NASA Astrophysics Data System (ADS)

Olsen, K.; Sneed, J. M.; Paul, V. J.

2016-06-01

Settlement is critical to maintaining coral cover on reefs, yet interspecific responses of coral planulae to common benthic macroalgae are not well characterized. Larval survival and settlement of two Caribbean reef-building corals, the broadcast-spawner Acropora palmata and the planulae-brooder Porites astreoides, were quantified following exposure to plastic algae controls and the green macroalga Halimeda opuntia. Survival and settlement rates were not significantly affected by the presence of H. opuntia in either species. However, ~10 % of P. astreoides larvae settled on the surface of the macroalga, whereas larvae of A. palmata did not. It is unlikely that corals that settle on macroalgae will survive post-settlement; therefore, H. opuntia may reduce the number of P. astreoides and other non-discriminatory larvae that survive to adulthood. Our results suggest that the presence of macroalgae on impacted reefs can have unexpected repercussions for coral recruitment and highlight discrepancies in settlement specificity between corals with distinct life history strategies.

Coral bleaching at Little Cayman, Cayman Islands 2009

NASA Astrophysics Data System (ADS)

van Hooidonk, Ruben J.; Manzello, Derek P.; Moye, Jessica; Brandt, Marilyn E.; Hendee, James C.; McCoy, Croy; Manfrino, Carrie

2012-06-01

The global rise in sea temperature through anthropogenic climate change is affecting coral reef ecosystems through a phenomenon known as coral bleaching; that is, the whitening of corals due to the loss of the symbiotic zooxanthellae which impart corals with their characteristic vivid coloration. We describe aspects of the most prevalent episode of coral bleaching ever recorded at Little Cayman, Cayman Islands, during the fall of 2009. The most susceptible corals were found to be, in order, Siderastrea siderea, Montastraea annularis, and Montastraea faveolata, while Diplora strigosa and Agaricia spp. were less so, yet still showed considerable bleaching prevalence and severity. Those found to be least susceptible were Porites porites, Porites astreoides, and Montastraea cavernosa. These observations and other reported observations of coral bleaching, together with 29 years (1982-2010) of satellite-derived sea surface temperatures, were used to optimize bleaching predictions at this location. To do this a Degree Heating Weeks (DHW) and Peirce Skill Score (PSS) analysis was employed to calculate a local bleaching threshold above which bleaching was expected to occur. A threshold of 4.2 DHW had the highest skill, with a PSS of 0.70. The method outlined here could be applied to other regions to find the optimal bleaching threshold and improve bleaching predictions.

Late Miocene Coral faunas of Iran (Zagros, Aghar, Firuz abad, Fars) palaeoecology and palaeobiogeography

NASA Astrophysics Data System (ADS)

Dehbozorgi, M.; Yazdi, M.; Torabi, H.

2009-04-01

Late Miocene Corals assemblage from Zagros Iran are investigated with respect to their palaeoecology and palaeobiogeography implications. This Corals are compared with fauna from Mediterranean Tethys and the Indopacific. Small foraminifers are used for biogeography and to support paleoecology interpretation. The studied section situated in the Zagros Mishan F.m is last depositions sea. A distinct horizon characterized by Porites- Antiguastrea assemblage associated Milliolid and Rotalia is interpreted a shallow bioclastic shoal. Patch reef with a porites and faviidae assemblage are a common feature of Oligocene and Miocene coral occurrence and indicate water depth of less than 20m. The diversity of corals in this area are low and all corals are hematypic. Miocene Corals from Mishan F.m Comprise 7 genera and occur in the single horizon or patch reef. This Corals and patch reefs are compared with corals and patch reefs in Qom F.m Central Iran. This corals report from this section: Antiguastrea sp., Monastrea sp., Favites sp., Porites sp., Dichocoenia sp., Asterohelia sp., Leptoria sp. Keywords: Miocene- Iran- Mishan-Zagros- Formation- Tethys seaway- Corals- Palaeoecology- palaeobiogeography.

A Chemical Approach to Mitigate Coral Bleaching

NASA Astrophysics Data System (ADS)

Marty-Rivera, M.; Yudowski, G.

2016-02-01

Changes in sea surface temperature and irradiance can induce bleaching and increase mortality in corals. Coral bleaching occurs when symbiotic algae living inside the coral is degraded or expelled, reducing the availability of energetic resources. Oxidative stress has been suggested as a possible molecular mechanism triggering bleaching. We hypothesized that reduction of reactive oxygen species (ROS) during stress could mitigate or prevent coral bleaching. We utilized the coral Porites Astreoides as our model to test the effects of two natural antioxidants, catechin and Resveratrol, on thermally induced bleaching. Coral fragments were exposed to four treatments: high temperature (32°C), high temperature plus antioxidants (1μM), ambient temperature (25°C), or ambient temperature (25°C) plus antioxidant for four days. A total of 8 corals were used per treatment. We measured several photobiological parameters, such as maximum quantum yield and light curves to assess the viability of symbiodinium spp. after thermal stress in the presence of antioxidants. Preliminary experiments on a model species, the sea anemone Aiptasia pallida and corals, showed that exposure to antioxidants reduced intracellular levels of ROS. Additionally, antioxidant-treated anemones showed higher photosynthetic efficiency (67%) than those exposed to high-temperature alone.

Coral distribution patterns in Miocene Reefs of Anguilla, Leeward Islands, West Indies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, A.B.; Johnson, K.G.

1988-01-01

Anguilla, a 27 by 5 km island at 18/sup 0/13'N, 63/sup 0/05'W, parallels the northwest edge of the Anguilla bank (St. Martin plateau) in the outer lesser Angilles volcanic arc, which was active from the Eocene to Oligocene. Except for scattered exposures of tuff or basalt, the island is composed predominantly of reefal limestones and marls of the 70-m thick, middle Miocene Anguilla Formation, deposited on a shallow inner shelf platform extending from volcanoes near St. Martin. The reef framework consists of branched and platy corals interspersed with calcareous sand lenses. Although the limestones have been uplifted and subjected tomore » minor faulting, little evidence supports extensive transport across a slope. Coral distribution patterns have been quantified across the reefal units by point-counting species occurrences at 0.16-m intervals within 1-m/sup 2/ quadrants placed haphazardly across vertical exposures. Eight coral species (of possibly 18 total) were recorded. Cluster analysis delineated four facies: (1) a low-diversity facies dominated by branched Porites, (2) an intermediate diversity facies dominated by branched Porites, (3) a high-diversity facies dominated by massive Montastraea, Siderastrea, and Porites, and (4) an intermediate diversity facies dominated by platy Porites. These facies consists of lenses, no more than 100 m long and 2 m high, arranged in no apparent regular sequence. Thus, they do not represent zones across a depth gradient. Comparisons with living Caribbean reefs suggests that the Anguilla Miocene reefs were similar to small, modern, backreef fringing and patch reefs near the San Blas Islands of Panama, reefs whose variable composition and patchy distribution depend largely on sedimentation and current patterns.« less

Short-Term Coral Bleaching Is Not Recorded by Skeletal Boron Isotopes

PubMed Central

Schoepf, Verena; McCulloch, Malcolm T.; Warner, Mark E.; Levas, Stephen J.; Matsui, Yohei; Aschaffenburg, Matthew D.; Grottoli, Andréa G.

2014-01-01

Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

Short-term coral bleaching is not recorded by skeletal boron isotopes.

PubMed

Schoepf, Verena; McCulloch, Malcolm T; Warner, Mark E; Levas, Stephen J; Matsui, Yohei; Aschaffenburg, Matthew D; Grottoli, Andréa G

2014-01-01

Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

Ingestion of Microplastics and Their Impact on Calcification in Reef-Building Corals

NASA Astrophysics Data System (ADS)

Zink, C. P.; Smith, R. T.

2016-02-01

Since the early 1970's, researchers began identifying plastics and other sources of litter as harmful to ecosystems. In recent years, there's been a growing concern about microscopic plastic debris (microplastics) and its impact on marine organisms. Likewise, microplastics are currently and continuously being documented from environmental samples on a global scale. The ecosystems most likely affected by their presence are shallow marine habitats, such as near-shore coral reefs. One concern is that microplastics may be ingested by reef-building corals and negatively impact their physiology. In this study, two species of Caribbean reef-building corals, Orbicella faveolata and Porites porites were investigated for rates of ingesting microplastics. Coral samples were incubated with 100μm micro-beads manufactured with a fluorescent label to aid in recovery and quantification from the coral tissue. Following the consumption of plastic, we measured instantaneous rates of calcification as a proxy for physiological performance compared to controls. Our results indicate that corals ingest microplastic particles and maintain them internally for at least 24 hours. Our initial findings suggest that the ingestion of ≥ 3 microplastic particles cm-2 may negatively impact rates of coral calcification. In light of these preliminary findings, further investigations should examine the long-term effect of environmentally relevant concentrations of microplastics on reef corals and its potential detriment to reef building capacity.

Super instrumental El Niño events recorded by a Porites coral from the South China Sea

NASA Astrophysics Data System (ADS)

Wang, Xijie; Deng, Wenfeng; Liu, Xi; Wei, Gangjian; Chen, Xuefei; Zhao, Jian-xin; Cai, Guanqiang; Zeng, Ti

2018-03-01

The 2-7-year periodicities recorded in fossil coral records have been widely used to identify paleo-El Niño events. However, the reliability of this approach in the South China Sea (SCS) has not been assessed in detail. Therefore, this paper presents monthly resolution geochemical records covering the period 1978-2015 obtained from a Porites coral recovered from the SCS to test the reliability of this method. The results suggest that the SCS coral reliably recorded local seawater conditions and the super El Niño events that occurred over the past 3 decades, but does not appear to have been sensitive enough to record all the other El Niños. In detail, the Sr/Ca series distinctly documents only the two super El Niños of 1997-1998 and 2014-2016 as obvious low values, but does not match the Oceanic Niño Index well. The super El Niño of 1982-1983 was identified by the growth hiatus caused by the coral bleaching and subsequent death of the coral. Three distinct stepwise variations occur in the δ13C series that are coincident with the three super El Niños, which may be related to a substantial decline in endosymbiotic zooxanthellae density caused by the increase in temperature during an El Niño or the selective utilization of different zooxanthellaes that was required to survive in the extreme environment. The increase in rainfall and temperatures over the SCS during El Niños counteracts the effects on seawater δ18O (δ18Osw) and salinity; consequently, coral Δδ18O series can be used as a proxy for δ18Osw and salinity, but are not appropriate for identifying El Niño activity. The findings presented here suggest that the method to identify paleo-El Niño activity based on the 2-7-year periodicities preserved in the SCS coral records might not be reliable, because the SCS is on the edge of El Niño anomalies due to its great distance from the central equatorial Pacific and the imprints of weak and medium strength El Niño events may not be recorded by the

Effects of Submarine Groundwater Discharge (SGD) on the Growth of the Lobe Coral Porites lobata in Maunalua Bay, Hawaii.

NASA Astrophysics Data System (ADS)

Lubarsky, K.

2016-02-01

Submarine groundwater discharge (SGD) constitutes a large percentage of the freshwater inputs onto coastal coral reefs on high islands such as the Hawaiian Islands, although the impact of SGD on coral reef health is currently understudied. In Maunalua Bay, on Oahu, Hawaii, SGD is discharged onto shallow reef flats from discrete seeps, creating natural gradients of water chemistry across the reef flat. We used this system to investigate rates of growth of the lobe coral Porites lobata across a gradient of SGD influence at two study sites within the bay, and to characterize the variation in water chemistry gradient over space and time due to SGD. SGD input at these sites is tidally modulated, and the groundwater itself is brackish and extremely nutrient-rich (mean=190 μM NO3- at the Black Point study site, mean=40 μM NO3- at Wailupe Beach Park), with distinct carbonate signatures at both study sites. Coral nubbins were placed across the gradient for 6 months, and growth was measured using three metrics: surface area (photo analysis), buoyant weight, and linear extension. Various chemical parameters, including pH, salinity, total alkalinity, nutrients, and chlorphyll were sampled at the same locations across the gradient over 24 hour periods in the spring and fall in order to capture spatial and temporal variation in water chemistry due to the SGD plume. Spatial patterns and temporal variation in water chemistry were correlated with the observed spatial patterns in coral growth across the SGD gradient.

Large-amplitude internal waves sustain coral health during thermal stress

NASA Astrophysics Data System (ADS)

Schmidt, Gertraud M.; Wall, Marlene; Taylor, Marc; Jantzen, Carin; Richter, Claudio

2016-09-01

Ocean warming is a major threat for coral reefs causing widespread coral bleaching and mortality. Potential refugia are thus crucial for coral survival. Exposure to large-amplitude internal waves (LAIW) mitigated heat stress and ensured coral survival and recovery during and after an extreme heat anomaly. The physiological status of two common corals, Porites lutea and Pocillopora meandrina, was monitored in host and symbiont traits, in response to LAIW-exposure throughout the unprecedented 2010 heat anomaly in the Andaman Sea. LAIW-exposed corals of both species survived and recovered, while LAIW-sheltered corals suffered partial and total mortality in P. lutea and P. meandrina, respectively. LAIW are ubiquitous in the tropics and potentially generate coral refuge areas. As thermal stress to corals is expected to increase in a warming ocean, the mechanisms linking coral bleaching to ocean dynamics will be crucial to predict coral survival on a warming planet.

Reduced calcification and lack of acclimatization by coral colonies growing in areas of persistent natural acidification

PubMed Central

Crook, Elizabeth D.; Cohen, Anne L.; Rebolledo-Vieyra, Mario; Hernandez, Laura; Paytan, Adina

2013-01-01

As the surface ocean equilibrates with rising atmospheric CO2, the pH of surface seawater is decreasing with potentially negative impacts on coral calcification. A critical question is whether corals will be able to adapt or acclimate to these changes in seawater chemistry. We use high precision CT scanning of skeletal cores of Porites astreoides, an important Caribbean reef-building coral, to show that calcification rates decrease significantly along a natural gradient in pH and aragonite saturation (Ωarag). This decrease is accompanied by an increase in skeletal erosion and predation by boring organisms. The degree of sensitivity to reduced Ωarag measured on our field corals is consistent with that exhibited by the same species in laboratory CO2 manipulation experiments. We conclude that the Porites corals at our field site were not able to acclimatize enough to prevent the impacts of local ocean acidification on their skeletal growth and development, despite spending their entire lifespan in low pH, low Ωarag seawater. PMID:23776217

Does seaweed-coral competition make seaweeds more palatable?

NASA Astrophysics Data System (ADS)

Longo, G. O.; Hay, M. E.

2015-03-01

Seaweed-coral interactions are increasingly common on modern coral reefs, but the dynamics, processes, and mechanisms affecting these interactions are inadequately understood. We investigated the frequency and effect of seaweed-coral contacts for common seaweeds and corals in Belize. Effects on corals were evaluated by measuring the frequency and extent of bleaching when contacted by various seaweeds, and effects on a common seaweed were evaluated by assessing whether contact with coral made the seaweed more palatable to the sea urchin Diadema antillarum. Coral-seaweed contacts were particularly frequent between Agaricia corals and the seaweed Halimeda opuntia, with this interaction being associated with coral bleaching in 95 % of contacts. Pooling across all coral species, H. opuntia was the seaweed most commonly contacting corals and most frequently associated with localized bleaching at the point of contact. Articulated coralline algae, Halimeda tuna and Lobophora variegata also frequently contacted corals and were commonly associated with bleaching. The common corals Agaricia and Porites bleached with similar frequency when contacted by H. opuntia (95 and 90 %, respectively), but Agaricia experienced more damage than Porites when contacted by articulated coralline algae or H. tuna. When spatially paired individuals of H. opuntia that had been in contact with Agaricia and not in contact with any coral were collected from the reefs and offered to D. antillarum, urchins consumed about 150 % more of thalli that had been competing with Agaricia. Contact and non-contact thalli did not differ in nutritional traits (ash-free-dry-mass, C or N concentrations), suggesting that Halimeda chemical defenses may have been compromised by coral-algal contact. If competition with corals commonly enhances seaweed palatability, then the dynamics and nuances of small-scale seaweed-coral-herbivore interactions at coral edges are deserving of greater attention in that such

Reproductive ecology and early life history traits of the brooding coral, Porites astreoides, from shallow to mesophotic zones

NASA Astrophysics Data System (ADS)

Goodbody-Gringley, Gretchen; Wong, Kevin H.; Becker, Danielle M.; Glennon, Keegan; de Putron, Samantha J.

2018-06-01

Early life history traits of brooding corals are often affected by the environmental conditions experienced by parental colonies. Such parental effects can impact offspring survival, which influences the overall success of a population as well as resilience to environmental challenges. This study examines the reproductive ecology and early life history traits of the brooding coral Porites astreoides across a depth gradient in Bermuda. Fecundity, larval size, larval Symbiodinium density, and settlement success, as well as post-metamorphic juvenile survival, growth, and Symbiodinium density were compared across three reef sites representing an inshore patch reef (2-5 m), an offshore rim reef (8-10 m), and an upper-mesophotic reef (30-33 m). Although fecundity did not differ across sites, larvae produced by colonies on the patch reef site were smaller, had lower Symbiodinium densities, and had lower rates of settlement and juvenile survival compared to larvae from colonies on the rim and upper-mesophotic reef sites. Larvae produced by colonies from the rim and upper-mesophotic sites did not differ in size or Symbiodinium densities; however, rates of settlement, growth, and survival were higher for larvae from the upper-mesophotic site compared to those from the rim reef site. These results indicate that offspring quality and success vary among sites with differing environmental conditions and may imply higher recruitment potential and resilience for upper-mesophotic corals.

The Delineation of Coral Bleaching Thresholds and Future Reef Health, Little Cayman Cayman Islands

NASA Astrophysics Data System (ADS)

Manfrino, C.; Van Hooidonk, R. J.; Manzello, D.; Hendee, J.

2011-12-01

The global rise in sea temperature through anthropogenic climate change is affecting coral reef ecosystems through a phenomenon known as coral bleaching; a common reaction to thermally induced physiological stress in reef-building corals that often leads to coral mortality. We describe aspects of the most prevalent episode of coral bleaching ever recorded at Little Cayman, Cayman Islands, during the fall of 2009. Scleractinian coral species exhibiting susceptibility to thermal stress and bleaching in Little Cayman were, in order, Siderastrea siderea, Montastraea annularis, and Montastraea faveolata, while Diplora strigosa and Agaricia spp. were less so, yet still showed considerable bleaching prevalence and severity. In contrast, the least susceptible were Porites porites, Porites astreoides, and Montastraea cavernosa. These observations and other reported observations of coral bleaching, together with 29 years (1982 - 2010) of satellite-derived sea surface temperatures, were used in a Degree Heating Weeks (DHW) and Peirce Skill Score (PSS) analysis to calculate a bleaching threshold above which bleaching was expected to occur. A threshold of 4.2 DHW had the highest skill, with a PSS of 0.70. This threshold and susceptibility ranking are used in combination with SST data from global, coupled ocean-atmosphere general circulation models (GCM) from the fourth IPCC assessment to forecast future reef health on Little Cayman. While these GCMs possess skill in reproducing many aspects of climate, they vary in their ability to correctly capture such parameters as the tropical ocean seasonal cycle and El Niño Southern Oscillation (ENSO) variability. These model weaknesses likely reduce the skill of coral bleaching predictions. To overcome this, a multi-model ensemble of GCMs are corrected for their mean, annual cycle and ENSO variability prior to calculating future thermal stress. Preliminary results show that from 2045 on Little Cayman is likely to see more than two

Miocene reef corals: A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frost, S.H.

1988-01-01

Tectonic blockage in the Middle East of westward-flowing Tethys surface circulation during the latest Oligocene led to creation in the earliest Miocene of endemic Mediterranean, Western Atlantic-Caribbean, and Indo-Pacific realms. A great reduction in reef coral diversity from 60-80 Oligocene species to 25-35 early Miocene species occurred in the Western Atlantic-Caribbean and Mediterranean areas accompanied by a decrease in reef growth. A slower and less drastic change apparently occurred in the Indo-Pacific area. Early Miocene reef corals of the Western Atlantic-Caribbean comprise a transition between the cosmopolitan Oligocene fauna and its endemic mid-Miocene to modern counterpart. Although early Miocene reefsmore » were dominated by a Porites-Montastrea assemblage, eastward flow of Pacific circulation brought with it ''exotic'' corals such as Coscinaraea and Pseudocolumnastrea. Also, many cosmopolitan genera persisted from the Oligocene. During the middle to late Miocene, most of the species still living on Holocene reefs evolved. As the Mediterranean basin became more restricted, there was a slow decline in reef corals from 20 - 25 species in the Aquitainian to less than five species in the Messinian. Eustatic lowstand led to the extinction of reef-building corals in the late Messinian. In the Indo-Pacific, Neogene evolution of reef corals was conservative. Excluding the Acroporidae and Seriatoporidae, most Holocene framework species had evolved by the middle Miocene. Interplay between regional tectonics and eustatic sea level changes led to extensive development of middle to late Miocene pinnacle reefs over the southwestern Pacific.« less

Bacterial populations and adaptations in the mucus layers on living corals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ducklow, H.W.; Mitchell, R.

1979-07-01

The external mucus layers of the stony coral Porites astreoides and the soft corals Palythoa sp. and Heteroxenia fuscesens are inhabited by communities of marine heterotrophic bacteria. Population levels of bacteria in coral mucus may be regulated by the self-cleaning behavior of the host. Bacterial populations in coral mucus respond to stresses applied to the host coral by growing to higher population levels in the mucus, indicating that these are populations of viable organisms closely attuned to host metabolism. Members of these microbial populations utilize the mucus compounds and may play a role in processing coral mucus for reef detritusmore » feeders. One such species, Vibrio alginolyticus, grows rapidly on Heteroxenia mucus, is attracted to dissolved mucus, and possesses a mechanism to maintain itself on the coral surface.« less

Effect of light and brine shrimp on skeletal δ 13C in the Hawaiian coral Porites compressa: a tank experiment

NASA Astrophysics Data System (ADS)

Grottoli, Andréa G.

2002-06-01

Previous experimental fieldwork showed that coral skeletal δ13C values decreased when solar intensity was reduced, and increased in the absence of zooplankton. However, actual seasonal changes in solar irradiance levels are typically less pronounced than those used in the previous experiment and the effect of increases in the consumption of zooplankton in the coral diet on skeletal δ13C remains relatively unknown. In the present study, the effects of four different light and heterotrophy regimes on coral skeletal δ13C values were measured. Porites compressa corals were grown in outdoor flow-through tanks under 112%, 100%, 75%, and 50% light conditions at the Hawaii Institute of Marine Biology, Hawaii. In addition, corals were fed either zero, low, medium, or high concentrations of brine shrimp. Decreases in light from 100% resulted in significant decreases in δ13C that is most likely due to a corresponding decrease in photosynthesis. Increases in light to 112% also resulted in a decrease in δ13C values. This latter response may be a consequence of photoinhibition. The overall curved response in δ13C values was described by a significant quadratic function. Increases in brine shrimp concentrations resulted in increased skeletal δ13C levels. This unexpected outcome appears to be attributable to enhanced nitrogen supply associated with the brine shrimp diet which led to increased zooxanthellae concentrations, increased photosynthesis rates, and thus increased δ13C values. This result highlights the potential influence of nutrients from heterotrophically acquired carbon in maintaining the zooxanthellae-host symbiosis in balance. In addition, evidence is presented that suggests that coral skeletal growth and δ13C are decoupled. These results increase our knowledge of how light and heterotrophy affects the δ13C of coral skeletons.

Clipperton Atoll (eastern Pacific): oceanography, geomorphology, reef-building coral ecology and biogeography

NASA Astrophysics Data System (ADS)

Glynn, P. W.; Veron, J. E. N.; Wellington, G. M.

1996-06-01

Coral reef geomorphology and community composition were investigated in the tropical northeastern Pacific during April 1994. Three areas were surveyed in the Revillagigedo Islands (Mexico), and an intensive study was conducted on Clipperton Atoll (1,300 km SW of Acapulco), including macro-scale surface circulation, sea surface temperature (SST) climatology, geomorphology, coral community structure, zonation, and biogeography. Satellite-tracked drifter buoys from 1979 1993 demonstrated complex patterns of surface circulation with dominantly easterly flow (North Equatorial Counter Current, NECC), but also westerly currents (South Equatorial Current, SEC) that could transport propagules to Clipperton from both central and eastern Pacific regions. The northernmost latitude reached by the NECC is not influenced by El Niño-Southern Oscillation (ENSO) events, but easterly flow velocity evidently is accelerated at such times. Maximum NECC flow rates indicate that the eastern Pacific barrier can be bridged in 60 to 120 days. SST anomalies at Clipperton occur during ENSO events and were greater at Clipperton in 1987 than during 1982 1983. Shallow (15 18 m)and deep (50 58 m) terraces are present around most of Clipperton, probably representing Modern and late Pleistocene sea level stands. Although Clipperton is a well developed atoll with high coral cover, the reef-building fauna is depauperate, consisting of only 7 species of scleractinian corals belonging to the genera Pocillopora, Porites, Pavona and Leptoseris, and 1 species of hydrocoral in the genus Millepora. The identities of the one Pocilpopora species and one of the two Porites species are still unknown. Two of the remaining scleractinians ( Pavona minuta, Leptoseris scabra) and the hydrocoral ( Millepora exaesa), all formerly known from central and western Pacific localities, represent new eastern Pacific records. Scleractinian corals predominate (10 100% cover) over insular shelf depths of 8 to 60m, and crustose

Competitive interactions between corals and turf algae depend on coral colony form.

PubMed

Swierts, Thomas; Vermeij, Mark Ja

2016-01-01

Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral-turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

The ploys of sex: relationships among the mode of reproduction, body size and habitats of coral-reef brittlestars

NASA Astrophysics Data System (ADS)

Hendler, Gordon; Littman, Barbara S.

1986-08-01

Observations were made of 33 species of brittlestars (3980 specimens) from specific substrata collected in four zones on the Belize Barrier Reef, Caribbean Sea. The body size of most species of brittlestars with planktonic larvae differs significantly among different substrata. Generally, individuals from the calcareous alga Halimeda opuntia are smallest, those found in corals ( Porites porites, Madracis mirabilis, and Agaricia tenuifolia) are larger, and those from coral rubble are the largest. This suggests that brittlestars with planktonic larvae move to new microhabitats as they grow. In contrast, most brooding and fissiparous species are relatively small and their size-distributions are similar among all substrata. Halimeda harbours denser concentrations of brittlestars and more small and juvenile individuals than the other substrata. Juveniles of the brooding and fissiparous species are most common in Halimeda on the Back Reef whereas juveniles developing from planktonic larvae are most common in Halimeda patches in deeper water. Fissiparity and brooding may be means for individuals (genomes) of small, apomictic species to reach large size (and correspondingly high fecundities) in patchy microhabitats that select for small body sizes. Small brittlestar species and juveniles are most numerous in the microhabitats called refuge-substrata, such as Halimeda, which may repel predators and reduce environmental stress. Whether young brittlestars are concentrated in refuge-substrata through settlement behavior, migration, or differential survival remains unknown. Experiments revealed that coral polyps kill small brittlestars, perhaps accounting for the rarity of small and juvenile brittlestars in coral substrata.

Distinct Bacterial Communities Associated with Massive and Branching Scleractinian Corals and Potential Linkages to Coral Susceptibility to Thermal or Cold Stress

PubMed Central

Liang, Jiayuan; Yu, Kefu; Wang, Yinghui; Huang, Xueyong; Huang, Wen; Qin, Zhenjun; Pan, Ziliang; Yao, Qiucui; Wang, Wenhuan; Wu, Zhengchao

2017-01-01

It is well known that different coral species have different tolerances to thermal or cold stress, which is presumed to be related to the density of Symbiodinium. However, the intrinsic factors between stress-tolerant characteristics and coral-associated bacteria are rarely studied. In this study, 16 massive coral and 9 branching coral colonies from 6 families, 10 genera, and 18 species were collected at the same time and location (Xinyi Reef) in the South China Sea to investigate the bacterial communities. The results of an alpha diversity analysis showed that bacterial diversities associated with massive corals were generally higher than those with branching corals at different taxonomic levels (phylum, class, order, and so on). In addition, hierarchical clustering tree and PCoA analyses showed that coral species were clustered into two large groups according to the similarity of bacterial communities. Group I consisted of massive Goniastrea, Plesiastrea, Leptastrea, Platygyra, Echinopora, Porites, and Leptoria, and group II consisted of branching Acropora and Pocillopora. These findings suggested that both massive corals and branching corals have their own preference for the choice of associated bacteria, which may be involved in observed differences in thermal/cold tolerances. Further analysis found that 55 bacterial phyla, including 43 formally described phyla and 12 candidate phyla, were detected in these coral species. Among them, 52 phyla were recovered from the massive coral group, and 46 phyla were recovered from the branching coral group. Formally described coral pathogens have not been detected in these coral species, suggesting that they are less likely to be threatened by disease in this geographic area. This study highlights a clear relationship between the high complexity of bacterial community associated with coral, skeletal morphology of coral and potentially tolerances to thermal or cold stress. PMID:28642738

Competitive interactions between corals and turf algae depend on coral colony form

PubMed Central

Vermeij, Mark JA

2016-01-01

Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral–turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship. PMID:27190707

Coral communities of the remote atoll reefs in the Nansha Islands, southern South China Sea.

PubMed

Zhao, M X; Yu, K F; Shi, Q; Chen, T R; Zhang, H L; Chen, T G

2013-09-01

During the months of May and June in the year 2007, a survey was conducted regarding coral reef communities in the remote atolls (Zhubi Reef and Meiji Reef) of Nansha Islands, southern South China Sea. The goals of the survey were to: (1) for the first time, compile a scleractinian coral check-list; (2) estimate the total richness, coral cover, and growth forms of the community; and (3) describe preliminary patterns of community structure according to geomorphological units. Findings of this survey revealed a total of 120 species of scleractinia belonging to 40 genera, while the average coral cover was 21 %, ranging from less than 10 % to higher than 50 %. Branching and massive corals were also found to be the most important growth forms of the whole coral community, while Acropora, Montipora, and Porites were the three dominant genera in the overall region, with their contributions to total coral cover measuring 21, 22, and 23 %, respectively. Overall, coral communities of the Nansha Islands were in a relative healthy condition with high species diversity and coral cover. Spatial pattern of coral communities existed among various geomorphological units. Mean coral cover was highest in the patch reef within the lagoon, followed by the fore reef slope, reef flat, and lagoon slope. The greatest contributors to total coral cover were branching Acropora (45 %) in the lagoon slope, branching Montipora (44 %) in the reef flat, and massive Porites (51 %) in the patch reef. Coral cover in the fore reef revealed a greater range of genera than in other habitats. The leeward fore reef slope had higher coral cover (> 50 %) when compared with the windward slope (< 10 %). The coral communities of the inner reef flat were characterized by higher coral cover (27 %) and dominant branching Montipora corals, while lower coral cover (4 %) was dominated by Psammocora with massive growth forms on the outer reef flat. Destructive fishing and coral bleaching were two major threats to

Unlocking the coral calcification process: Insights from boron isotope measurements and a skeletal growth model

NASA Astrophysics Data System (ADS)

Mollica, N. R.; Guo, W.; Cohen, A. L.; Huang, K. F.; Foster, G. L.; Donald, H.; Solow, A.

2017-12-01

Carbonate skeletons of scleractinian corals are important archives of ocean climate and environmental change. However, corals don't accrete their skeletons directly from ambient seawater, but from a calcifying fluid whose composition is strongly regulated. There is mounting evidence that the carbonate chemistry of this calcifying fluid significantly impacts the amount of carbonate the coral can precipitate, which in turn affects the geochemical composition of the skeleton produced. However the mechanistic link between calcifying fluid (cf) chemistry, particularly the up-regulation of pHcf and thereby aragonite saturation state (Ωcf), and coral calcification is not well understood. We explored this link by combining boron isotope measurements with in situ measurements of seawater temperature, salinity, and DIC to estimate Ωcf of nine Porites corals from four Pacific reefs. Associated calcification rates were quantified for each core via CT scanning. We do not observe a relationship between calcification rates and Ωcf or Ωsw. Instead, when we deconvolve calcification into linear extension and skeletal density, a significant correlation is observed between density and Ωcf, and also Ωsw while extension does not correlate with either. These observations are consistent with the two-step model of coral calcification, in which skeleton is secreted in two distinct phases: vertical extension creating new skeletal elements, followed by lateral thickening of existing elements that are covered by living tissue. We developed a numerical model of Porites skeletal growth that builds on this two-step model and links skeletal density with the external seawater environment via its influence on the chemistry of coral calcifying fluid. We validated the model using existing coral skeletal datasets from six Porites species collected across five reef sites, and quantified the effects of each seawater parameter (e.g. temperature, pH, DIC) on skeletal density. Our findings illustrate

Long-term impacts of coral bleaching events on the world's warmest reefs.

PubMed

Burt, John; Al-Harthi, Suaad; Al-Cibahy, Ashraf

2011-10-01

The southern Arabian Gulf houses some of the most thermally tolerant corals on earth, but severe bleaching in the late 1990s caused widespread mortality. More than a decade later, corals still dominated benthos (mean: 40 ± 3% cover on 10 sites spanning > 350 km; range: 11.0-65.6%), but coral communities varied spatially. Sites to the west generally had low species richness and coral cover (mean: 3.2 species per transect, 31% cover), with Porites dominated communities (88% of coral) that are distinct from more diverse and higher cover eastern sites (mean: 10.3 species per transect, 62% cover). These patterns reflect both the more extreme bleaching to the west in the late 1990s as well as the higher faviid dominated recruitment to the east in subsequent years. There has been limited recovery of the formerly dominant Acropora, which now represents <1% of the benthos, likely as a result of recruitment failure. Results indicate that severe bleaching can have substantial long-term impacts on coral communities, even in areas with corals tolerant to environmental extremes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Gross and Microscopic Lesions in Corals from Micronesia.

PubMed

Work, T M; Aeby, G S; Hughen, K A

2016-01-01

The authors documented gross and microscopic morphology of lesions in corals on 7 islands spanning western, southern, and eastern Micronesia, sampling 76 colonies comprising 30 species of corals among 18 genera, with Acropora, Porites, and Montipora dominating. Tissue loss comprised the majority of gross lesions sampled (41%), followed by discoloration (30%) and growth anomaly (29%). Of 31 cases of tissue loss, most lesions were subacute (48%), followed by acute and chronic (26% each). Of 23 samples with discoloration, most were dark discoloration (40%), with bleaching and other discoloration each constituting 30%. Of 22 growth anomalies, umbonate growth anomalies composed half, with exophytic, nodular, and rugose growth anomalies composing the remainder. On histopathology, for 9 cases of dark discoloration, fungal infections predominated (77%); for 7 bleached corals, depletion of zooxanthellae from the gastrodermis made up a majority of microscopic diagnoses (57%); and for growth anomalies other than umbonate, hyperplasia of the basal body wall was the most common microscopic finding (63%). For the remainder of the gross lesions, no single microscopic finding constituted >50% of the total. Host response varied with the agent present on histology. Fragmentation of tissues was most often associated with algae (60%), whereas necrosis dominated (53%) for fungi. Two newly documented potentially symbiotic tissue-associated metazoans were seen in Porites and Montipora. Findings of multiple potential etiologies for a given gross lesion highlight the importance of incorporating histopathology in coral disease surveys. This study also expands the range of corals infected with cell-associated microbial aggregates. © The Author(s) 2015.

Gross and microscopic lesions in corals from Micronesia

USGS Publications Warehouse

Work, Thierry M.; Aeby, Greta S.; Hughen, Konrad A.

2015-01-01

The authors documented gross and microscopic morphology of lesions in corals on 7 islands spanning western, southern, and eastern Micronesia, sampling 76 colonies comprising 30 species of corals among 18 genera, with Acropora, Porites, and Montipora dominating. Tissue loss comprised the majority of gross lesions sampled (41%), followed by discoloration (30%) and growth anomaly (29%). Of 31 cases of tissue loss, most lesions were subacute (48%), followed by acute and chronic (26% each). Of 23 samples with discoloration, most were dark discoloration (40%), with bleaching and other discoloration each constituting 30%. Of 22 growth anomalies, umbonate growth anomalies composed half, with exophytic, nodular, and rugose growth anomalies composing the remainder. On histopathology, for 9 cases of dark discoloration, fungal infections predominated (77%); for 7 bleached corals, depletion of zooxanthellae from the gastrodermis made up a majority of microscopic diagnoses (57%); and for growth anomalies other than umbonate, hyperplasia of the basal body wall was the most common microscopic finding (63%). For the remainder of the gross lesions, no single microscopic finding constituted >50% of the total. Host response varied with the agent present on histology. Fragmentation of tissues was most often associated with algae (60%), whereas necrosis dominated (53%) for fungi. Two newly documented potentially symbiotic tissue-associated metazoans were seen in Porites and Montipora. Findings of multiple potential etiologies for a given gross lesion highlight the importance of incorporating histopathology in coral disease surveys. This study also expands the range of corals infected with cell-associated microbial aggregates.

Oil spill recorded by skeletal δ13C of Porites corals in Weizhou Island, Beibu Gulf, Northern South China Sea

NASA Astrophysics Data System (ADS)

Xu, Shendong; Yu, Kefu; Wang, Yinghui; Liu, Tao; Jiang, Wei; Wang, Shaopeng; Chu, Minghang

2018-07-01

Oil, is one kind of natural product of biological origin which is depleted in 13C. Coral skeletal δ13C is an important archive of environmental and climatic change. However, few studies have been conducted on the effect of oil spill on the coral skeletal δ13C at present. This kind of research is useful for us to obtain environmental and climatic information from coral skeletal δ13C. In this study, two continuously growing Porites corals (W1 and W3), aged 22 and 31 years (1994-2015 and 1985-2015), respectively, were collected from the fringing reef of Weizhou Island in October 2015, coral skeletal δ13C and δ18O were analyzed. Besides, seawater was collected during an oil spill in 28 January 2018, and was used for δ13CDIC (δ13C values of DIC) analysis. The purpose is to explore the potential impact of oil spills on δ13CDIC and coral δ13C. δ13CDIC value during oil spill was significantly lower than that of normal seawater (Δδ13C≈-2.38‰). Coral δ13C of both two coral colonies showed lower values since 2008 (average value of δ13C before and after 2008 change from -2.04 ± 0.48‰ to -3.33 ± 0.55‰ ‰ and -1.77 ± 0.49‰ to -2.88 ± 0.54‰ of W1 and W3 respectively), especially, several abrupt negative shifts in 2008, 2009, 2011, 2012 and 2014 when oil spills occurred (extent of δ13C variation were W1：-3.08‰, -1.82‰, -1.82‰, -1.53‰, -1.37‰; W3：-3.27‰, -1.8‰, -1.91‰, -1.21‰, -1.13‰ respectively). Our results clearly show that degradation of oil by microorganisms when oil spill occurs should render a decrease in the 13C/12C ratio of the seawater dissolved inorganic carbon (DIC) which is the ultimate carbon source of coral calcification.

Nuclear weapons produced 236U, 239Pu and 240Pu archived in a Porites Lutea coral from Enewetak Atoll.

PubMed

Froehlich, M B; Tims, S G; Fallon, S J; Wallner, A; Fifield, L K

2017-11-01

A slice from a Porites Lutea coral core collected inside the Enewetak Atoll lagoon, within 15 km of all major nuclear tests conducted at the atoll, was analysed for 236 U, 239 Pu and 240 Pu over the time interval 1952-1964 using a higher time resolution than previously reported for a parallel slice from the same core. In addition two sediment samples from the Koa and Oak craters were analysed. The strong peaks in the concentrations of 236 U and 239 Pu in the testing years are confirmed to be considerably wider than the flushing time of the lagoon. This is likely due to the growth mechanism of the coral. Following the last test in 1958 atom concentrations of both 236 U and 239 Pu decreased from their peak values by more than 95% and showed a seasonal signal thereafter. Between 1959 and 1964 the weighted average of the 240 Pu/ 239 Pu atom ratio is 0.124 ± 0.008 which is similar to that in the lagoon sediments (0.129 ± 0.006) but quite distinct from the global fallout value of ∼0.18. This, and the high 239,240 Pu and 236 U concentrations in the sediments, provides clear evidence that the post-testing signal in the coral is dominated by remobilisation of the isotopes from the lagoon sediments rather than from global fallout. Copyright © 2017 Elsevier Ltd. All rights reserved.

Endosymbiotic flexibility associates with environmental sensitivity in scleractinian corals.

PubMed

Putnam, Hollie M; Stat, Michael; Pochon, Xavier; Gates, Ruth D

2012-11-07

Flexibility in biological systems is seen as an important driver of macro-ecosystem function and stability. Spatially constrained endosymbiotic settings, however, are less studied, although environmental thresholds of symbiotic corals are linked to the function of their endosymbiotic dinoflagellate communities. Symbiotic flexibility is a hypothesized mechanism that corals may exploit to adapt to climate change. This study explores the flexibility of the coral-Symbiodinium symbiosis through quantification of Symbiodinium ITS2 sequence assemblages in a range of coral species and genera. Sequence assemblages are expressed as an index of flexibility incorporating phylogenetic divergence and relative abundance of Symbiodinium sequences recovered from the host. This comparative analysis reveals profound differences in the flexibility of corals for Symbiodinium, thereby classifying corals as generalists or specifists. Generalists such as Acropora and Pocillopora exhibit high intra- and inter-species flexibility in their Symbiodinium assemblages and are some of the most environmentally sensitive corals. Conversely, specifists such as massive Porites colonies exhibit low flexibility, harbour taxonomically narrow Symbiodinium assemblages, and are environmentally resistant corals. Collectively, these findings challenge the paradigm that symbiotic flexibility enhances holobiont resilience. This underscores the need for a deeper examination of the extent and duration of the functional benefits associated with endosymbiotic diversity and flexibility under environmental stress.

Inhibition of coral recruitment by macroalgae and cyanobacteria

USGS Publications Warehouse

Kuffner, I.B.; Walters, L.J.; Becerro, M.A.; Paul, V.J.; Ritson-Williams, R.; Beach, K.S.

2006-01-01

Coral recruitment is a key process in the maintenance and recovery of coral reef ecosystems. While intense competition between coral and algae is often assumed on reefs that have undergone phase shifts from coral to algal dominance, data examining the competitive interactions involved, particularly during the larval and immediate post-settlement stage, are scarce. Using a series of field and outdoor seawater table experiments, we tested the hypothesis that common species of macroalgae and cyanobacteria inhibit coral recruitment. We examined the effects of Lyngbya spp., Dictyota spp., Lobophora variegata (J. V. Lamouroux) Womersley, and Chondrophycus poiteaui (J. V. Lamouroux) Nam (formerly Laurencia poiteaui) on the recruitment success of Porites astreoides larvae. All species but C. poiteaui caused either recruitment inhibition or avoidance behavior in P. astreoides larvae, while L. confervoides and D. menstrualis significantly increased mortality rates of P. astreoides recruits. We also tested the effect of some of these macrophytes on larvae of the gorgonian octocoral Briareum asbestinum. Exposure to Lyngbya majuscula reduced survival and recruitment in the octocoral larvae. Our results provide evidence that algae and cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. On reefs experiencing phase shifts or temporary algal blooms, the restocking of adult coral populations may be slowed due to recruitment inhibition, thereby perpetuating reduced coral cover and limiting coral community recovery. ?? Inter-Research 2006.

Identity and diversity of coral endosymbionts (zooxanthellae) from three Palauan reefs with contrasting bleaching, temperature and shading histories.

PubMed

Fabricius, K E; Mieog, J C; Colin, P L; Idip, D; van Oppen, M J H

2004-08-01

The potential of corals to associate with more temperature-tolerant strains of algae (zooxanthellae, Symbiodinium) can have important implications for the future of coral reefs in an era of global climate change. In this study, the genetic identity and diversity of zooxanthellae was investigated at three reefs with contrasting histories of bleaching mortality, water temperature and shading, in the Republic of Palau (Micronesia). Single-stranded conformation polymorphism and sequence analysis of the ribosomal DNA internal transcribed spacer (ITS)1 region was used for genotyping. A chronically warm but partly shaded coral reef in a marine lake that is hydrographically well connected to the surrounding waters harboured only two single-stranded conformation polymorphism profiles (i.e. zooxanthella communities). It consisted only of Symbiodinium D in all 13 nonporitid species and two Porites species investigated, with the remaining five Porites harbouring C*. Despite the high temperature in this lake (> 0.5 degrees above ambient), this reef did not suffer coral mortality during the (1998) bleaching event, however, no bleaching-sensitive coral families and genera occur in the coral community. This setting contrasts strongly with two other reefs with generally lower temperatures, in which 10 and 12 zooxanthella communities with moderate to low proportions of clade D zooxanthellae were found. The data indicate that whole coral assemblages, when growing in elevated seawater temperatures and at reduced irradiance, can be composed of colonies associated with the more thermo-tolerant clade D zooxanthellae. Future increases in seawater temperature might, therefore, result in an increasing prevalence of Symbiodinium phylotype D in scleractinian corals, possibly associated with a loss of diversity in both zooxanthellae and corals. Copyright 2004 Blackwell Publishing Ltd

Responses of reef building corals to microplastic exposure.

PubMed

Reichert, Jessica; Schellenberg, Johannes; Schubert, Patrick; Wilke, Thomas

2018-06-01

Pollution of marine environments with microplastic particles (i.e. plastic fragments <5 mm) has increased rapidly during the last decades. As these particles are mainly of terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened. Recent studies revealed that microplastic ingestion can have adverse effects on marine invertebrates. However, little is known about its effects on small-polyp stony corals that are the main framework builders in coral reefs. The goal of this study is to characterise how different coral species I) respond to microplastic particles and whether the exposure might II) lead to health effects. Therefore, six small-polyp stony coral species belonging to the genera Acropora, Pocillopora, and Porites were exposed to microplastics (polyethylene, size 37-163 μm, concentration ca. 4000 particles L -1 ) over four weeks, and responses and effects on health were documented. The study showed that the corals responded differentially to microplastics. Cleaning mechanisms (direct interaction, mucus production) but also feeding interactions (i.e. interaction with mesenterial filaments, ingestion, and egestion) were observed. Additionally, passive contact through overgrowth was documented. In five of the six studied species, negative effects on health (i.e. bleaching and tissue necrosis) were reported. We here provide preliminary knowledge about coral-microplastic-interactions. The results call for further investigations of the effects of realistic microplastic concentrations on growth, reproduction, and survival of stony corals. This might lead to a better understanding of resilience capacities in coral reef ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seafloor morphology and coral habitat variability in a volcanic environment: Kaloko-Honokohau National Park, Hawaii, USA

USGS Publications Warehouse

Gibbs, Ann E.; Cochran, Susan A.

2011-01-01

Kaloko–Honokohau National Historical Park (KAHO) is one of three National Park lands along the leeward, west, or Kona, coast of the island of Hawaii, USA. The park includes 596 acres (2.4 km2) of submerged lands and marine resources within its official boundaries. The offshore region of KAHO, part of the insular shelf of the island of Hawaii, comprises a volcanic embayment that extends nearly 3.5 km alongshore and varies in width between 120 and 875 m from the shoreline to the 40 m isobath, the limit of the high-resolution bathymetry. Multiple Holocene volcanic flows coalesce within Kaloko-Honokohau National Historical Park (KAHO) on the island of Hawaii to create a complex offshore morphology. The volcanic-dominated morphology includes flat to gently sloping volcanic benches, boulder fields, cliffs and ledges, pinnacles, ridges, arches, and steep shelf escarpments. Each of these environments provide distinct habitat zones for coral species, ranging from isolated heads of Porites lobata and Pocillopora meandrina to dense thickets of Porites compressa. In contrast to coral habitat elsewhere in the Hawaiian Islands, where coral typically populates relict carbonate platforms, coral cover in KAHO is typically only a thin veneer of live coral and rubble on exposed volcanic pavement. In only a few locations does coral or accreted carbonate reef obscure the underlying volcanic surface.

Bacterial profiling of White Plague Disease across corals and oceans indicates a conserved and distinct disease microbiome

PubMed Central

Roder, Cornelia; Arif, Chatchanit; Daniels, Camille; Weil, Ernesto; Voolstra, Christian R

2014-01-01

Coral diseases are characterized by microbial community shifts in coral mucus and tissue, but causes and consequences of these changes are vaguely understood due to the complexity and dynamics of coral-associated bacteria. We used 16S rRNA gene microarrays to assay differences in bacterial assemblages of healthy and diseased colonies displaying White Plague Disease (WPD) signs from two closely related Caribbean coral species, Orbicella faveolata and Orbicella franksi. Analysis of differentially abundant operational taxonomic units (OTUs) revealed strong differences between healthy and diseased specimens, but not between coral species. A subsequent comparison to data from two Indo-Pacific coral species (Pavona duerdeni and Porites lutea) revealed distinct microbial community patterns associated with ocean basin, coral species and health state. Coral species were clearly separated by site, but also, the relatedness of the underlying bacterial community structures resembled the phylogenetic relationship of the coral hosts. In diseased samples, bacterial richness increased and putatively opportunistic bacteria were consistently more abundant highlighting the role of opportunistic conditions in structuring microbial community patterns during disease. Our comparative analysis shows that it is possible to derive conserved bacterial footprints of diseased coral holobionts that might help in identifying key bacterial species related to the underlying etiopathology. Furthermore, our data demonstrate that similar-appearing disease phenotypes produce microbial community patterns that are consistent over coral species and oceans, irrespective of the putative underlying pathogen. Consequently, profiling coral diseases by microbial community structure over multiple coral species might allow the development of a comparative disease framework that can inform on cause and relatedness of coral diseases. PMID:24350609

Internal pH regulation facilitates in situ long-term acclimation of massive corals to end-of-century carbon dioxide conditions.

PubMed

Wall, M; Fietzke, J; Schmidt, G M; Fink, A; Hofmann, L C; de Beer, D; Fabricius, K E

2016-08-01

The resilience of tropical corals to ocean acidification depends on their ability to regulate the pH within their calcifying fluid (pHcf). Recent work suggests pHcf homeostasis under short-term exposure to pCO2 conditions predicted for 2100, but it is still unclear if pHcf homeostasis can be maintained throughout a corals lifetime. At CO2 seeps in Papua New Guinea, massive Porites corals have grown along a natural seawater pH gradient for decades. This natural gradient, ranging from pH 8.1-7.4, provides an ideal platform to determine corals' pHcf (using boron isotopes). Porites maintained a similar pHcf (~8.24) at both a control (pH 8.1) and seep-influenced site (pH 7.9). Internal pHcf was slightly reduced (8.12) at seawater pH 7.6, and decreased to 7.94 at a site with a seawater pH of 7.4. A growth response model based on pHcf mirrors the observed distribution patterns of this species in the field. We suggest Porites has the capacity to acclimate after long-time exposure to end-of-century reduced seawater pH conditions and that strong control over pHcf represents a key mechanism to persist in future oceans. Only beyond end-of-century pCO2 conditions do they face their current physiological limit of pH homeostasis and pHcf begins to decrease.

Spatial Variation in Background Mortality among Dominant Coral Taxa on Australia's Great Barrier Reef

PubMed Central

Pisapia, Chiara; Pratchett, Morgan S.

2014-01-01

Even in the absence of major disturbances (e.g., cyclones, bleaching), corals are consistently subject to high levels of background mortality, which undermines individual fitness and resilience of coral colonies. Partial mortality may impact coral response to climate change by reducing colony ability to recover between major acute stressors. This study quantified proportion of injured versus uninjured colonies (the prevalence of injuries) and instantaneous measures of areal extent of injuries across individual colonies (the severity of injuries), in four common coral species along the Great Barrier Reef in Australia: massive Porites, encrusting Montipora, Acropora hyacinthus and Pocillopora damicornis. A total of 2,276 adult colonies were surveyed three latitudinal sectors, nine reefs and 27 sites along 1000 km2 on the Great Barrier Reef. The prevalence of injuries was very high, especially for Porites spp (91%) and Montipora encrusting (85%) and varied significantly, but most lay at small spatial scales (e.g., among colonies positioned <10-m apart). Similarly, severity of background partial mortality was surprisingly high (between 5% and 21%) but varied greatly among colonies within the same site and habitat. This study suggests that intraspecific variation in partial mortality between adjacent colonies may be more important than variation between colonies in different latitudinal sectors or reefs. Differences in the prevalence and severity of background partial mortality have significant ramifications for coral capacity to cope with increasing acute disturbances, such as climate-induced coral bleaching. These data are important for understanding coral responses to increasing stressors, and in particular for predicting their capacity to recover between subsequent disturbances. PMID:24959921

Spatial variation in background mortality among dominant coral taxa on Australia's Great Barrier Reef.

PubMed

Pisapia, Chiara; Pratchett, Morgan S

2014-01-01

Even in the absence of major disturbances (e.g., cyclones, bleaching), corals are consistently subject to high levels of background mortality, which undermines individual fitness and resilience of coral colonies. Partial mortality may impact coral response to climate change by reducing colony ability to recover between major acute stressors. This study quantified proportion of injured versus uninjured colonies (the prevalence of injuries) and instantaneous measures of areal extent of injuries across individual colonies (the severity of injuries), in four common coral species along the Great Barrier Reef in Australia: massive Porites, encrusting Montipora, Acropora hyacinthus and Pocillopora damicornis. A total of 2,276 adult colonies were surveyed three latitudinal sectors, nine reefs and 27 sites along 1000 km2 on the Great Barrier Reef. The prevalence of injuries was very high, especially for Porites spp (91%) and Montipora encrusting (85%) and varied significantly, but most lay at small spatial scales (e.g., among colonies positioned <10-m apart). Similarly, severity of background partial mortality was surprisingly high (between 5% and 21%) but varied greatly among colonies within the same site and habitat. This study suggests that intraspecific variation in partial mortality between adjacent colonies may be more important than variation between colonies in different latitudinal sectors or reefs. Differences in the prevalence and severity of background partial mortality have significant ramifications for coral capacity to cope with increasing acute disturbances, such as climate-induced coral bleaching. These data are important for understanding coral responses to increasing stressors, and in particular for predicting their capacity to recover between subsequent disturbances.

Patterns of coral disease across the Hawaiian Archipelago: Relating disease to environment

USGS Publications Warehouse

Aeby, G.S.; Williams, G.J.; Franklin, E.C.; Kenyon, J.; Cox, E.F.; Coles, S.; Work, Thierry M.

2011-01-01

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing

Patterns of Coral Disease across the Hawaiian Archipelago: Relating Disease to Environment

PubMed Central

Aeby, Greta S.; Williams, Gareth J.; Franklin, Erik C.; Kenyon, Jean; Cox, Evelyn F.; Coles, Steve; Work, Thierry M.

2011-01-01

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing

Do elevated nutrients and organic carbon on Philippine reefs increase the prevalence of coral disease?

NASA Astrophysics Data System (ADS)

Kaczmarsky, L.; Richardson, L. L.

2011-03-01

Characterizations of Philippine coral diseases are very limited. The two most common, ulcerative white spot disease (UWS) and massive Porites growth anomalies (MPGA), target the genus Porites, a dominant reef-building genus. This is the first investigation in the Philippines to detect positive correlations between coral disease, nutrient levels, and organic carbon. A total of 5,843 Porites colonies were examined. Water and sediment samples were collected for analyses of nutrients (total nitrogen and phosphorus) and total organic carbon at 15 sites along a 40.5 km disease gradient, which was previously shown to positively correlate with human population levels. Results suggest that outbreaks of UWS and MPGAs are driven by elevated nutrient and organic carbon levels. Although the variables analyzed could be proxies for other causative agents (e.g., high sediment levels), the results provide quantitative evidence linking relatively higher coral disease prevalence to an anthropogenically impacted environment.

Exploring Mesophotic Depths Off North Philippine Sea: Coral Reefs on the Benham Bank Seamount

NASA Astrophysics Data System (ADS)

Nacorda, H. M. E.; Dizon, R. M.; Meñez, L. A. B.; Nañola, C. L., Jr.; Hernandez, H. B.; Quimpo, F. A. T. R.; De Jesus, D. O.; Nacorda, J. O. O.; Tingson, K. N.; Roa-Chio, P. B. L.; Pardo, K. C. E.; Licuanan, W. R. Y.; Aliño, P. M.

2016-02-01

We conducted observational surveys of coral reef biodiversity at <60 m on the summit of the Benham Bank Seamount off North Philippine Sea. The reefs were found with excellent cover (75 to 100%) of mostly tiered, thick, rigid and foliose plate-forming Porites rus. Over 60 species of bony and cartilaginous fish were recorded; their estimated biomass ranged from 17 to 102 mt km-2. Four species of the green algae Halimeda dominated the reef-associated macroalgae, some of which were epiphytic. The prominent coral-attached sponges had arborescent growth form but irregular forms also occurred. The coarse biogenic surface sediments harbored mostly aerobic macroinfauna. These results comprise the first account of the biodiversity of an offshore mesophotic coral reef seamount. Although its diversity appears less than the shallower fringing reefs of the Philippines' Pacific Seaboard, the dynamic environment remains important to fisheries.

Changes in Bleaching Susceptibility among Corals Subject to Ocean Warming and Recurrent Bleaching in Moorea, French Polynesia

PubMed Central

Pratchett, Morgan S.; McCowan, Dominique; Maynard, Jeffrey A.; Heron, Scott F.

2013-01-01

Background Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. Methodology/Principal Findings This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Conclusions/Significance Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to

Changes in bleaching susceptibility among corals subject to ocean warming and recurrent bleaching in Moorea, French Polynesia.

PubMed

Pratchett, Morgan S; McCowan, Dominique; Maynard, Jeffrey A; Heron, Scott F

2013-01-01

Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to sustained and ongoing ocean warming.

Coral Sr/Ca-based sea surface temperature and air temperature variability from the inshore and offshore corals in the Seribu Islands, Indonesia.

PubMed

Cahyarini, Sri Yudawati; Zinke, Jens; Troelstra, Simon; Suharsono; Aldrian, Edvin; Hoeksema, B W

2016-09-30

The ability of massive Porites corals to faithfully record temperature is assessed. Porites corals from Kepulauan Seribu were sampled from one inshore and one offshore site and analyzed for their Sr/Ca variation. The results show that Sr/Ca of the offshore coral tracked SST, while Sr/Ca variation of the inshore coral tracked ambient air temperature. In particular, the inshore SST variation is related to air temperature anomalies of the urban center of Jakarta. The latter we relate to air-sea interactions modifying inshore SST associated with the land-sea breeze mechanism and/or monsoonal circulation. The correlation pattern of monthly coral Sr/Ca with the Niño3.4 index and SEIO-SST reveals that corals in the Seribu islands region respond differently to remote forcing. An opposite response is observed for inshore and offshore corals in response to El Niño onset, yet similar to El Niño mature phase (December to February). SEIO SSTs co-vary strongly with SST and air temperature variability across the Seribu island reef complex. The results of this study clearly indicate that locations of coral proxy record in Indonesia need to be chosen carefully in order to identify the seasonal climate response to local and remote climate and anthropogenic forcing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antibacterial Activity of Hawaiian Corals: Possible Protection from Disease?

NASA Astrophysics Data System (ADS)

Gochfeld, D. J.; Aeby, G. S.; Miller, J. D.

2006-12-01

Reports of coral diseases in the Caribbean have appeared with increasing frequency over the past two decades; however, records of coral diseases in the Pacific have lagged far behind. Recent surveys of coral disease in the Hawaiian Islands indicate relatively low, but consistent, levels of disease throughout the inhabited Main and uninhabited Northwestern Hawaiian Islands, and demonstrate variation in levels of disease among the major genera of Hawaiian corals. Although little is known about immune defense to disease in corals, one potential mechanism of defense is the production of antimicrobial compounds that protect corals from pathogens. A preliminary survey of antibacterial chemical defenses among three dominant species of Hawaiian corals was undertaken. Crude aqueous extracts of Porites lobata, Pocillopora meandrina and Montipora capitata were tested against nine strains of bacteria in a growth inhibition assay. Inhibitory extracts were further tested to determine whether their effects were cytostatic or cytotoxic. The bacteria selected included known coral pathogens, potential marine pathogens found in human waste and strains previously identified from the surfaces of Hawaiian corals. Extracts from all three species of coral exhibited a high degree of antibacterial activity, but also a high degree of selectivity against different bacterial strains. In addition, some extracts were stimulatory to some bacteria. In addition to interspecific variability, extracts also exhibited intraspecific variability, both within and between sites. Hawaiian corals have significant antibacterial activity, which may explain the relatively low prevalence of disease in these corals; however, further characterization of pathogens specifically responsible for disease in Hawaiian corals is necessary before we can conclude that antibacterial activity protects Hawaiian corals from disease.

The chemical cue tetrabromopyrrole from a biofilm bacterium induces settlement of multiple Caribbean corals

PubMed Central

Sneed, Jennifer M.; Sharp, Koty H.; Ritchie, Kimberly B.; Paul, Valerie J.

2014-01-01

Microbial biofilms induce larval settlement for some invertebrates, including corals; however, the chemical cues involved have rarely been identified. Here, we demonstrate the role of microbial biofilms in inducing larval settlement with the Caribbean coral Porites astreoides and report the first instance of a chemical cue isolated from a marine biofilm bacterium that induces complete settlement (attachment and metamorphosis) of Caribbean coral larvae. Larvae settled in response to natural biofilms, and the response was eliminated when biofilms were treated with antibiotics. A similar settlement response was elicited by monospecific biofilms of a single bacterial strain, Pseudoalteromonas sp. PS5, isolated from the surface biofilm of a crustose coralline alga. The activity of Pseudoalteromonas sp. PS5 was attributed to the production of a single compound, tetrabromopyrrole (TBP), which has been shown previously to induce metamorphosis without attachment in Pacific acroporid corals. In addition to inducing settlement of brooded larvae (P. astreoides), TBP also induced larval settlement for two broadcast-spawning species, Orbicella (formerly Montastraea) franksi and Acropora palmata, indicating that this compound may have widespread importance among Caribbean coral species. PMID:24850918

Community Structure Of Coral Reefs In Saebus Island, Sumenep District, East Java

NASA Astrophysics Data System (ADS)

Rizmaadi, Mada; Riter, Johannes; Fatimah, Siti; Rifaldi, Riyan; Yoga, Arditho; Ramadhan, Fikri; Ambariyanto, Ambariyanto

2018-02-01

Increasing degradation coral reefs ecosystem has created many concerns. Reduction of this damage can only be done with good and proper management of coral reef ecosystem based on existing condition. The condition of coral reef ecosystem can be determined by assessing its community structure. This study investigates community structure of coral reef ecosystems around Saebus Island, Sumenep District, East Java, by using satellite imagery analysis and field observations. Satellite imagery analysis by Lyzenga methods was used to determine the observation stations and substrate distribution. Field observations were done by using Line Intercept Transect method at 4 stations, at the depth of 3 and 10 meters. The results showed that the percentage of coral reef coverage at the depth of 3 and 10 meters were 64.36% and 59.29%, respectively, and included in fine coverage category. This study found in total 25 genera from 13 families of corals at all stations. The most common species found were Acropora, Porites, and Pocillopora, while the least common species were Favites and Montastrea. Average value of Diversity, Uniformity and Dominancy indices were 2.94, 0.8 and 0.18 which include as medium, high, and low category, respectively. These results suggest that coral reef ecosystems around Saebus Island is in a good condition.

Additive negative effects of anthropogenic sedimentation and warming on the survival of coral recruits.

PubMed

Fourney, Francesca; Figueiredo, Joana

2017-09-28

Corals worldwide are facing population declines due to global climate change and local anthropogenic impacts. Global climate change effects are hard to tackle but recent studies show that some coral species can better handle climate change stress when provided with additional energy resources. The local stressor that most undermines energy acquisition is sedimentation because it impedes coral heterotrophic feeding and their ability to photosynthesize. To investigate if reducing local sedimentation will enable corals to better endure ocean warming, we quantitatively assessed the combined effects of increased temperature and sedimentation (concentration and turbidity) on the survival of coral recruits of the species, Porites astreoides. We used sediment from a reef and a boat basin to mimic natural sediment (coarse) and anthropogenic (fine) sediment (common in dredging), respectively. Natural sediment did not negatively impact coral survival, but anthropogenic sediment did. We found that the capacity of coral recruits to survive under warmer temperatures is less compromised when anthropogenic sedimentation is maintained at the lowest level (30 mg.cm -2 ). Our study suggests that a reduction of US-EPA allowable turbidity from 29 Nephelometric Turbidity Units (NTU) above background to less than 7 NTU near coral reefs would facilitate coral recruit survival under current and higher temperatures.

Oligocene and Early Miocene coral faunas from Iran: palaeoecology and palaeobiogeography

NASA Astrophysics Data System (ADS)

Schuster, F.; Wielandt, U.

Oligocene and Early Miocene coral assemblages from three sections of central Iran are investigated with respect to their palaeoecological and palaeobiogeographic implications. These corals are compared with faunas from the Mediterranean Tethys and the Indopacific. Associated larger foraminifers are used for biostratigraphy and to support the palaeoecological interpretation. The studied sections are situated in the foreland basins of the Iranian Plate which is structured into a fore-arc and a back-arc basin separated by a volcanic arc. The coral assemblages from Abadeh indicate a shallowing-upward trend. Infrequently distributed solitary corals at the base of the section indicate a turbid environment. Above, a distinct horizon characterised by a Leptoseris-Stylophora assemblage associated with lepidocyclinids and planktonic foraminifers is interpreted as maximum flooding surface. Small patch reefs with a Porites-Faviidae assemblage are a common feature of Late Oligocene to Early Miocene coral occurrences and indicate water depths of less than 20m. The diversity of the coral faunas shows marked differences. Oligocene corals from the Esfahan-Sirjan fore-arc basin comprise more than 45 species of 32 genera and occur in a wide range of environments. Early Miocene corals from the Qom back-arc basin are less frequent, show a lower diversity (13 genera with 15 species) and occur in single horizons or small patch reefs.

Mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event.

PubMed

García-Sais, Jorge R; Williams, Stacey M; Amirrezvani, Ali

2017-01-01

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals from Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd 490 ) was observed, suggesting that light attenuation, as influenced by water turbidity and depth, played a major role in coral protection during the bleaching event ("sunblock effect"). Responses of coral assemblages varied after the bleaching event, including shifts of cover from massive corals ( Orbicella spp.) to opportunistic ( Porites astreoides ) and branching corals ( Madracis auretenra , P. porites ) and/or turf algae; partial recovery of reef substrate cover by O. annularis complex; and no measurable changes in coral assemblages before and after the event.

Assessing land use, sedimentation, and water quality stressors as predictors of coral reef condition in St. Thomas, U.S. Virgin Islands.

PubMed

Oliver, L M; Fisher, W S; Fore, L; Smith, A; Bradley, P

2018-03-13

Coral reef condition on the south shore of St. Thomas, U.S. Virgin Islands, was assessed at various distances from Charlotte Amalie, the most densely populated city on the island. Human influence in the area includes industrial activity, wastewater discharge, cruise ship docks, and impervious surfaces throughout the watershed. Anthropogenic activity was characterized using a landscape development intensity (LDI) index, sedimentation threat (ST) estimates, and water quality (WQ) impairments in the near-coastal zone. Total three-dimensional coral cover, reef rugosity, and coral diversity had significant negative coefficients for LDI index, as did densities of dominant species Orbicella annularis, Orbicella franksi, Montastraea cavernosa, Orbicella faveolata, and Porites porites. However, overall stony coral colony density was not significantly correlated with stressors. Positive relationships between reef rugosity and ST, between coral diversity and ST, and between coral diversity and WQ were unexpected because these stressors are generally thought to negatively influence coral growth and health. Sponge density was greater with higher disturbance indicators (ST and WQ), consistent with reports of greater resistance by sponges to degraded water quality compared to stony corals. The highest FoRAM (Foraminifera in Reef Assessment and Monitoring) indices indicating good water quality were found offshore from the main island and outside the harbor. Negative associations between stony coral metrics and LDI index have been reported elsewhere in the Caribbean and highlight LDI index potential as a spatial tool to characterize land-based anthropogenic stressor gradients relevant to coral reefs. Fewer relationships were found with an integrated stressor index but with similar trends in response direction.

Coral disease dynamics at a subtropical location, Solitary Islands Marine Park, eastern Australia

NASA Astrophysics Data System (ADS)

Dalton, Steven J.; Smith, Stephen D. A.

2006-03-01

Recent observations suggest that a spreading disease is increasingly contributing to hard coral mortality in the Solitary Islands Marine Park, NSW, Australia. This study determined coral disease prevalence and rate-of-spread through individual affected colonies and investigated the effect this epizootic had on coral populations at sites adjacent to South West Solitary Island. Quantitative data were collected between 2002 and 2004 using photographic and video methods, and visual census along radial arc belt transects. Disease similar to the reported white syndrome and white plague was apparent, spreading through hard coral species from the genera Turbinaria, Acropora, Goniastrea, Pocillopora, Stylophora and Porites. Coral disease prevalence varied between survey dates with mean prevalence increasing from 8.55% during March 2003 to 13.58% in June and declining to 7.75% in September and 6.21% during March 2004. There was a significant difference in mean prevalence between the affected species (p<0.001) and an overall difference between survey dates (p=0.001). Additionally, the rate-of-spread of coral disease through coral colonies determined using repeated, seasonal, still photographs followed similar patterns, with disease progression differing between affected species (p=0.004), and between survey dates (p<0.001). Analysis of the video-transects indicated significant difference in disease prevalence over larger spatial scales (100s of m). However, disease frequency did not vary significantly between 2002 and 2003.

Environmental versus genetic influences on growth rates of the corals Pocillopora eydouxi and Porites lobata (Anthozoa: Scleractinia)

USGS Publications Warehouse

Smith, L.W.; Wirshing, H.H.; Baker, A.C.; Birkeland, C.

2008-01-01

Reciprocal transplant experiments of the corals Pocillopora eydouxi Milne Edwards & Haime and Porites lobata Dana were carried out for an 18-month period from September 2004 to March 2006 between two back reef pools on Ofu Island, American Samoa, to test environmental versus genetic effects on skeletal growth rates. Skeletal growth of P. eydouxi showed environmental but not genetic effects, resulting in doubling of growth in Pool 300 compared with Pool 400. There were no environmental or genetic effects on skeletal growth of P. lobata. Pool 300 had more frequent and longer durations of elevated seawater temperatures than Pool 400, characteristics likely to decrease rather than increase skeletal growth. Pool 300 also had higher nutrient levels and flow velocities than Pool 400, characteristics that may increase skeletal growth. However, higher nutrient levels would be expected to increase skeletal growth in both species, but there was no difference between the pools in P. lobata growth. P. eydouxi is much more common in high-energy environments than P. lobata; thus the higher flow velocities in Pool 300 than in Pool 400 may have positively affected skeletal growth of P. eydouxi while not having a detectable effect on P. lobata. The greater skeletal growth of P. eydouxi in Pool 300 occurred despite the presence of clade D zooxanthellae in several source colonies in Pool 300, a genotype known to result in greater heat resistance but slower skeletal growth. Increased skeletal growth rates in higher water motion may provide P. eydouxi a competitive advantage in shallow, high-energy enviromnents where competition for space is intense. ?? 2008 by University of Hawai'i Press. All rights reserved.

[Community structure of zooxanthellate corals (Anthozoa: Scleractinia) in Carrizales coral reef, Pacific coast, Mexico].

PubMed

Reyes-Bonilla, Hector; Escobosa-González, Laura Elena; Cupul-Magaña, Amilcar L; Medina-Rosas, Pedro; Calderón-Aguilera, Luis E

2013-06-01

Coral reefs in the Mexican Pacific and notably those of the continental coastline of Colima state are still poorly studied. Fortunately, recent efforts have been carried out by researchers from different Mexican institutions to fill up these information gaps. The aim of this study was to determine the ecological structure of the rich and undisturbed coral building communities of Carrizales by using the point transect interception method (25m-long). For this, three survey expeditions were conducted between June and October 2005 and September 2006; and for comparison purposes, the reef was subdivided according to its position in the bay, and depth (0 to 5 m, and 6 to 10 m). Thirteen coral species were observed in the area, with Pocillopora verrucosa as the most abundant, contributing up to 32.8% of total cover, followed by Porites panamensis and Pocillopora capitata with 11% and 7%, respectively. Other species, Pocillopora damicornis, Pavona gigantea, Pocillopora eydouxi and Pocillopora inflata accounted for 1.5% to 2% of coral cover whereas the remaining five species had cover of less than 1%. Seven of the observed species represented new records for Colima state coastline: Pocillopora eydouxi, P inflata, P meandrina, Pavona duerdeni, P varians, Psammocora stellata and P contigua. This last species is a relevant record, because it has never been observed before in the Eastern Pacific. Although there was no significant difference (ANOVA, p = 0.478) neither in the abundance between the sides of the bay, nor between the depths considered, and the shallow zone observed the higher coral cover. Live coral cover was up to 61%, one of the highest ever reported for the Mexican Pacific, including the Gulf of California. The observed values of diversity (H' = 0.44 +/- 0.02), uniformity (J' = 0.76 +/- 0.02), and taxonomic distinctness index (delta* = 45.87 +/- 3.16), showed that currently this is the most important coral reef of Colima coastline. Currently, this region does not

Physiological and Biogeochemical Traits of Bleaching and Recovery in the Mounding Species of Coral Porites lobata: Implications for Resilience in Mounding Corals

DTIC Science & Technology

2013-05-02

each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves...maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals...lobata corals immediately following bleaching and throughout 11 months of recovery: photosynthesis (P), respiration (R), chlorophyll a (Chl a), total

Mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

PubMed Central

Amirrezvani, Ali

2017-01-01

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals from Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that light attenuation, as influenced by water turbidity and depth, played a major role in coral protection during the bleaching event (“sunblock effect”). Responses of coral assemblages varied after the bleaching event, including shifts of cover from massive corals (Orbicella spp.) to opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites) and/or turf algae; partial recovery of reef substrate cover by O. annularis complex; and no measurable changes in coral assemblages before and after the event. PMID:28761791

Macroalgal Extracts Induce Bacterial Assemblage Shifts and Sublethal Tissue Stress in Caribbean Corals

PubMed Central

Morrow, Kathleen M.; Ritson-Williams, Raphael; Ross, Cliff; Liles, Mark R.; Paul, Valerie J.

2012-01-01

Benthic macroalgae can be abundant on present-day coral reefs, especially where rates of herbivory are low and/or dissolved nutrients are high. This study investigated the impact of macroalgal extracts on both coral-associated bacterial assemblages and sublethal stress response of corals. Crude extracts and live algal thalli from common Caribbean macroalgae were applied onto the surface of Montastraea faveolata and Porites astreoides corals on reefs in both Florida and Belize. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene amplicons was used to examine changes in the surface mucus layer (SML) bacteria in both coral species. Some of the extracts and live algae induced detectable shifts in coral-associated bacterial assemblages. However, one aqueous extract caused the bacterial assemblages to shift to an entirely new state (Lobophora variegata), whereas other organic extracts had little to no impact (e.g. Dictyota sp.). Macroalgal extracts more frequently induced sublethal stress responses in M. faveolata than in P. astreoides corals, suggesting that cellular integrity can be negatively impacted in selected corals when comparing co-occurring species. As modern reefs experience phase-shifts to a higher abundance of macroalgae with potent chemical defenses, these macroalgae are likely impacting the composition of microbial assemblages associated with corals and affecting overall reef health in unpredicted and unprecedented ways. PMID:23028648

Macroalgal extracts induce bacterial assemblage shifts and sublethal tissue stress in Caribbean corals.

PubMed

Morrow, Kathleen M; Ritson-Williams, Raphael; Ross, Cliff; Liles, Mark R; Paul, Valerie J

2012-01-01

Benthic macroalgae can be abundant on present-day coral reefs, especially where rates of herbivory are low and/or dissolved nutrients are high. This study investigated the impact of macroalgal extracts on both coral-associated bacterial assemblages and sublethal stress response of corals. Crude extracts and live algal thalli from common Caribbean macroalgae were applied onto the surface of Montastraea faveolata and Porites astreoides corals on reefs in both Florida and Belize. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene amplicons was used to examine changes in the surface mucus layer (SML) bacteria in both coral species. Some of the extracts and live algae induced detectable shifts in coral-associated bacterial assemblages. However, one aqueous extract caused the bacterial assemblages to shift to an entirely new state (Lobophora variegata), whereas other organic extracts had little to no impact (e.g. Dictyota sp.). Macroalgal extracts more frequently induced sublethal stress responses in M. faveolata than in P. astreoides corals, suggesting that cellular integrity can be negatively impacted in selected corals when comparing co-occurring species. As modern reefs experience phase-shifts to a higher abundance of macroalgae with potent chemical defenses, these macroalgae are likely impacting the composition of microbial assemblages associated with corals and affecting overall reef health in unpredicted and unprecedented ways.

Do Skeletal Density Changes Within the Tissue Layer of Corals Affect Paleoclimate Reconstructions?

NASA Astrophysics Data System (ADS)

Griffiths, J. S.; DeLong, K. L.; Quinn, T.; Taylor, F. W.; Kilbourne, K. H.; Wagner, A. J.

2016-02-01

Sea surface temperature (SST) reconstructions from coral geochemistry provide information on past climate variability; however, not all coral studies agree on a common calibration slope. Therefore, understanding the impacts of coral skeletal growth on strontium-to-calcium ratios (Sr/Ca) and oxygen isotopic ratios (δ18O) is necessary to ensure accurate calibrations. The study of Gagan et al. (2012) suggests that for the Pacific coral genera Porites, SST calibrations for coral Sr/Ca and δ18O need to be adjusted to account for skeletal density changes in the tissue layer, which may attenuate the seasonal cycle in coral geochemistry. We attempt to duplicate those results and density patterns in several Porites lutea colonies from two locations, yet our results do not show an increase in density in the tissue layer. Another study with Montastraea faveolata reveals reduced seasonality in coral Sr/Ca compared to slower-growing Siderastrea siderea in close proximity and same water depth, suggesting the faster growing M. faveolata geochemistry may be attenuated. By measuring skeletal density changes by micromilling a standard volume throughout the tissue layer and immediately below, we find no pattern of skeletal accumulation in the tissue layer of multiple colonies of M. faveolata and S. siderea from different locations. We conclude that these species lay down all of their skeletal material at the skeleton surface, thus skeletal density changes in the tissue layer do not account for reduced seasonality. We propose that time averaging occurs in M. faveolata as a result of the coral polyp's deep calyces mixing time intervals in the adjacent thecal wall in which micromilling for geochemical analysis produces a sample area that contains several growth increments. Our results show that skeletal density growth effects cannot be applied to all coral genera and paves the way for new research on calyx depth as an alternative explanation for differences in coral calibration slopes.

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

NASA Astrophysics Data System (ADS)

Cole, C.; Finch, A. A.; Hintz, C.; Hintz, K.; Allison, N.

2018-06-01

Understanding how rising seawater pCO2 and temperatures impact coral aragonite accretion is essential for predicting the future of reef ecosystems. Here, we report 2 long-term (10-11 month) studies assessing the effects of temperature (25 and 28 °C) and both high and low seawater pCO2 (180-750 μatm) on the calcification, photosynthesis and respiration of individual massive Porites spp. genotypes. Calcification rates were highly variable between genotypes, but high seawater pCO2 reduced calcification significantly in 4 of 7 genotypes cultured at 25 °C but in only 1 of 4 genotypes cultured at 28 °C. Increasing seawater temperature enhanced calcification in almost all corals, but the magnitude of this effect was seawater pCO2 dependent. The 3 °C temperature increase enhanced calcification rate on average by 3% at 180 μatm, by 35% at 260 μatm and by > 300% at 750 μatm. The rate increase at high seawater pCO2 exceeds that observed in inorganic aragonites. Responses of gross/net photosynthesis and respiration to temperature and seawater pCO2 varied between genotypes, but rates of all these processes were reduced at the higher seawater temperature. Increases in seawater temperature, below the thermal stress threshold, may mitigate against ocean acidification in this coral genus, but this moderation is not mediated by an increase in net photosynthesis. The response of coral calcification to temperature cannot be explained by symbiont productivity or by thermodynamic and kinetic influences on aragonite formation.

Intraspecific variations in responses to ocean acidification in two branching coral species.

PubMed

Sekizawa, Ayami; Uechi, Hikaru; Iguchi, Akira; Nakamura, Takashi; Kumagai, Naoki H; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

2017-09-15

Ocean acidification is widely recognised to have a negative impact on marine calcifying organisms by reducing calcifications, but controversy remains over whether such organisms could cope with ocean acidification within a range of phenotypic plasticity and/or adapt to future acidifying ocean. We performed a laboratory rearing experiment using clonal fragments of the common branching corals Montipora digitata and Porites cylindrica under control and acidified seawater (lower pH) conditions (approximately 400 and 900μatm pCO 2 , respectively) and evaluated the intraspecific variations in their responses to ocean acidification. Intra- and interspecific variations in calcification and photosynthetic efficiency were evident according to both pCO 2 conditions and colony, indicating that responses to acidification may be individually variable at the colony level. Our results suggest that some corals may cope with ocean acidification within their present genotypic composition by adaptation through phenotypic plasticity, while others may be placed under selective pressures resulting in population alteration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Red fluorescent protein responsible for pigmentation in trematode-infected Porites compressa tissues.

PubMed

Palmer, Caroline V; Roth, Melissa S; Gates, Ruth D

2009-02-01

Reports of coral disease have increased dramatically over the last decade; however, the biological mechanisms that corals utilize to limit infection and resist disease remain poorly understood. Compromised coral tissues often display non-normal pigmentation that potentially represents an inflammation-like response, although these pigments remain uncharacterized. Using spectral emission analysis and cryo-histological and electrophoretic techniques, we investigated the pink pigmentation associated with trematodiasis, infection with Podocotyloides stenometre larval trematode, in Porites compressa. Spectral emission analysis reveals that macroscopic areas of pink pigmentation fluoresce under blue light excitation (450 nm) and produce a broad emission peak at 590 nm (+/-6) with a 60-nm full width at half maximum. Electrophoretic protein separation of pigmented tissue extract confirms the red fluorescence to be a protein rather than a low-molecular-weight compound. Histological sections demonstrate green fluorescence in healthy coral tissue and red fluorescence in the trematodiasis-compromised tissue. The red fluorescent protein (FP) is limited to the epidermis, is not associated with cells or granules, and appears unstructured. These data collectively suggest that the red FP is produced and localized in tissue infected by larval trematodes and plays a role in the immune response in corals.

Sensitivity of Calcification to Thermal Stress Varies among Genera of Massive Reef-Building Corals

PubMed Central

Carricart-Ganivet, Juan P.; Cabanillas-Terán, Nancy; Cruz-Ortega, Israel; Blanchon, Paul

2012-01-01

Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously

Reef-coral refugia in a rapidly changing ocean.

PubMed

Cacciapaglia, Chris; van Woesik, Robert

2015-06-01

This study sought to identify climate-change thermal-stress refugia for reef corals in the Indian and Pacific Oceans. A species distribution modeling approach was used to identify refugia for 12 coral species that differed considerably in their local response to thermal stress. We hypothesized that the local response of coral species to thermal stress might be similarly reflected as a regional response to climate change. We assessed the contemporary geographic range of each species and determined their temperature and irradiance preferences using a k-fold algorithm to randomly select training and evaluation sites. That information was applied to downscaled outputs of global climate models to predict where each species is likely to exist by the year 2100. Our model was run with and without a 1°C capacity to adapt to the rising ocean temperature. The results show a positive exponential relationship between the current area of habitat that coral species occupy and the predicted area of habitat that they will occupy by 2100. There was considerable decoupling between scales of response, however, and with further ocean warming some 'winners' at local scales will likely become 'losers' at regional scales. We predicted that nine of the 12 species examined will lose 24-50% of their current habitat. Most reductions are predicted to occur between the latitudes 5-15°, in both hemispheres. Yet when we modeled a 1°C capacity to adapt, two ubiquitous species, Acropora hyacinthus and Acropora digitifera, were predicted to retain much of their current habitat. By contrast, the thermally tolerant Porites lobata is expected to increase its current distribution by 14%, particularly southward along the east and west coasts of Australia. Five areas were identified as Indian Ocean refugia, and seven areas were identified as Pacific Ocean refugia for reef corals under climate change. All 12 of these reef-coral refugia deserve high-conservation status. © 2015 John Wiley & Sons Ltd.

Tracking Transmission of Apicomplexan Symbionts in Diverse Caribbean Corals

PubMed Central

Kirk, Nathan L.; Ritson-Williams, Raphael; Coffroth, Mary Alice; Miller, Margaret W.; Fogarty, Nicole D.; Santos, Scott R.

2013-01-01

Symbionts in each generation are transmitted to new host individuals either vertically (parent to offspring), horizontally (from exogenous sources), or a combination of both. Scleractinian corals make an excellent study system for understanding patterns of symbiont transmission since they harbor diverse symbionts and possess distinct reproductive modes of either internal brooding or external broadcast spawning that generally correlate with vertical or horizontal transmission, respectively. Here, we focused on the under-recognized, but apparently widespread, coral-associated apicomplexans (Protista: Alveolata) to determine if symbiont transmission depends on host reproductive mode. Specifically, a PCR-based assay was utilized towards identifying whether planula larvae and reproductive adults from brooding and broadcast spawning scleractinian coral species in Florida and Belize harbored apicomplexan DNA. Nearly all (85.5%; n = 85/89) examined planulae of five brooding species (Porites astreoides, Agaricia tenuifolia, Agaricia agaricites, Favia fragum, Mycetophyllia ferox) and adults of P. astreoides were positive for apicomplexan DNA. In contrast, no (n = 0/10) apicomplexan DNA was detected from planulae of four broadcast spawning species (Acropora cervicornis, Acropora palmata, Pseudodiploria strigosa, and Orbicella faveolata) and rarely in gametes (8.9%; n = 5/56) of these species sampled from the same geographical range as the brooding species. In contrast, tissue samples from nearly all (92.0%; n = 81/88) adults of the broadcast spawning species A. cervicornis, A. palmata and O. faveolata harbored apicomplexan DNA, including colonies whose gametes and planulae tested negative for these symbionts. Taken together, these data suggest apicomplexans are transmitted vertically in these brooding scleractinian coral species while the broadcast spawning scleractinian species examined here acquire these symbionts horizontally. Notably, these transmission patterns are

Isolation by distance across the Hawaiian Archipelago in the reef-building coral Porites lobata.

PubMed

Polato, Nicholas R; Concepcion, Gregory T; Toonen, Robert J; Baums, Iliana B

2010-11-01

There is an ongoing debate on the scale of pelagic larval dispersal in promoting connectivity among populations of shallow, benthic marine organisms. The linearly arranged Hawaiian Islands are uniquely suited to study scales of population connectivity and have been used extensively as a natural laboratory in terrestrial systems. Here, we focus on Hawaiian populations of the lobe coral Porites lobata, an ecosystem engineer of shallow reefs throughout the Pacific. Patterns of recent gene flow and population structure in P. lobata samples (n = 318) from two regions, the Hawaiian Islands (n = 10 sites) and from their nearest neighbour Johnston Atoll, were analysed with nine microsatellite loci. Despite its massive growth form, ∼ 6% of the samples from both regions were the product of asexual reproduction via fragmentation. Cluster analysis and measures of genetic differentiation indicated that P. lobata from the Hawaiian Islands are strongly isolated from those on Johnston Atoll (F(ST)  = 0.311; P < 0.001), with the descendants of recent migrants (n = 6) being clearly identifiable. Within the Hawaiian Islands, P. lobata conforms to a pattern of isolation by distance. Here, over 37% (P = 0.001) of the variation in genetic distance was explained by geographical distance. This pattern indicates that while the majority of ongoing gene flow in Hawaiian P. lobata occurs among geographically proximate reefs, inter-island distances are insufficient to generate strong population structure across the archipelago. © 2010 Blackwell Publishing Ltd.

Effects of two sediment types on the fluorescence yield of two Hawaiian scleractinian corals

USGS Publications Warehouse

Piniak, G.A.

2007-01-01

This study used non-invasive pulse-amplitude modulated (PAM) fluorometry to measure the maximum fluorescence yield (Fv/Fm) of two Hawaiian scleractinian coral species exposed to short-term sedimentation stress. Beach sand or harbor mud was applied to coral fragments in a flow-through aquarium system for 0-45 h, and changes in Fv/Fm were measured as a function of sediment type and length of exposure. Corals were monitored for up to 90 h to document recovery after sediment removal. Sediment deposition significantly decreased Fv/Fm in both species and was a function of sediment type and time. Corals that received sediment for 30 h or more had the greatest reduction in yield and exhibited little recovery over the course of the experiment. Harbor mud caused a greater reduction in Porites lobata yield than beach sand, whereas both sediment types had equally deleterious effects on Montipora capitata. Colony morphology and sediment type were important factors in determining yield reduction-P. lobata minimized damage from coarse sand grains by passive sediment rejection or accumulation in depressions in the skeleton, and fluorescence yield decreased most in corals exposed to sticky harbor mud or in colonies with flattened morphologies. Species-specific differences could not be tested due to differences in colony morphology and surface area. ?? 2007.

Discerning the timing and cause of historical mortality events in modern Porites from the Great Barrier Reef

NASA Astrophysics Data System (ADS)

Clark, Tara R.; Zhao, Jian-xin; Roff, George; Feng, Yue-xing; Done, Terence J.; Nothdurft, Luke D.; Pandolfi, John M.

2014-08-01

The life history strategies of massive Porites corals make them a valuable resource not only as key providers of reef structure, but also as recorders of past environmental change. Yet recent documented evidence of an unprecedented increase in the frequency of mortality in Porites warrants investigation into the history of mortality and associated drivers. To achieve this, both an accurate chronology and an understanding of the life history strategies of Porites are necessary. Sixty-two individual Uranium-Thorium (U-Th) dates from 50 dead massive Porites colonies from the central inshore region of the Great Barrier Reef (GBR) revealed the timing of mortality to have occurred predominantly over two main periods from 1989.2 ± 4.1 to 2001.4 ± 4.1, and from 2006.4 ± 1.8 to 2008.4 ± 2.2 A.D., with a small number of colonies dating earlier. Overall, the peak ages of mortality are significantly correlated with maximum sea-surface temperature anomalies. Despite potential sampling bias, the frequency of mortality increased dramatically post-1980. These observations are similar to the results reported for the Southern South China Sea. High resolution measurements of Sr/Ca and Mg/Ca obtained from a well preserved sample that died in 1994.6 ± 2.3 revealed that the time of death occurred at the peak of sea surface temperatures (SST) during the austral summer. In contrast, Sr/Ca and Mg/Ca analysis in two colonies dated to 2006.9 ± 3.0 and 2008.3 ± 2.0, suggest that both died after the austral winter. An increase in Sr/Ca ratios and the presence of low Mg-calcite cements (as determined by SEM and elemental ratio analysis) in one of the colonies was attributed to stressful conditions that may have persisted for some time prior to mortality. For both colonies, however, the timing of mortality coincides with the 4th and 6th largest flood events reported for the Burdekin River in the past 60 years, implying that factors associated with terrestrial runoff may have been

Coral population dynamics across consecutive mass mortality events.

PubMed

Riegl, Bernhard; Purkis, Sam

2015-11-01

Annual coral mortality events due to increased atmospheric heat may occur regularly from the middle of the century and are considered apocalyptic for coral reefs. In the Arabian/Persian Gulf, this situation has already occurred and population dynamics of four widespread corals (Acropora downingi, Porites harrisoni, Dipsastrea pallida, Cyphastrea micropthalma) were examined across the first-ever occurrence of four back-to-back mass mortality events (2009-2012). Mortality was driven by diseases in 2009, bleaching and subsequent diseases in 2010/2011/2012. 2009 reduced P. harrisoni cover and size, the other events increasingly reduced overall cover (2009: -10%; 2010: -20%; 2011: -20%; 2012: -15%) and affected all examined species. Regeneration was only observed after the first disturbance. P. harrisoni and A. downingi severely declined from 2010 due to bleaching and subsequent white syndromes, while D. pallida and P. daedalea declined from 2011 due to bleaching and black-band disease. C. microphthalma cover was not affected. In all species, most large corals were lost while fission due to partial tissue mortality bolstered small size classes. This general shrinkage led to a decrease of coral cover and a dramatic reduction of fecundity. Transition matrices for disturbed and undisturbed conditions were evaluated as Life Table Response Experiment and showed that C. microphthalma changed the least in size-class dynamics and fecundity, suggesting they were 'winners'. In an ordered 'degradation cascade', impacts decreased from the most common to the least common species, leading to step-wise removal of previously dominant species. A potentially permanent shift from high- to low-coral cover with different coral community and size structure can be expected due to the demographic dynamics resultant from the disturbances. Similarities to degradation of other Caribbean and Pacific reefs are discussed. As comparable environmental conditions and mortality patterns must be

Storm-generated coral fragments - A viable source of transplants for reef rehabilitation

USGS Publications Warehouse

Garrison, V.; Ward, G.

2008-01-01

Coral reefs throughout the world have been damaged by storms, diseases, coral predators, temperature anomalies, and human activities. During the past three decades, recovery has been limited and patchy. Although a damaged coral reef cannot be restored to its original condition, interest in reef restoration is increasing. In a pilot project in the Caribbean (US Virgin Islands), storm-produced fragments of Acropora palmata, A. cervicornis, and Porites porites were collected from donor reefs and transplanted to nearby degraded reefs. Sixty coral fragments were attached to dead-coral substrate (usually A. palmata skeletons), at similar depths from which they had been collected (1-3.5 m), using nylon cable ties. Seventy-five intact colonies were designated as controls. Study colonies were assessed at 6-month intervals for 2 years (1999-2001) and annually thereafter (through 2004). One-fourth of the 135 colonies and fragments monitored were alive at the conclusion of the 5-year study. Survival of control and transplanted A. cervicornis and P. porites was very low (median survival 2.4 and 1.8 years, respectively), with no significant differences between transplant and control colonies. Site and depth did not contribute significantly to A. palmata colony survival, but colony size and transplant/control status did. Probability of survival increased with colony size. Median survival for A. palmata was 1.3 years for transplant and 4.3 years for natural colonies when not controlled for size. A. palmata was the only viable candidate for reef rehabilitation. Storm swells were the primary cause of mortality.

Living with marginal coral communities: Diversity and host-specificity in coral-associated barnacles in the northern coral distribution limit of the East China Sea.

PubMed

Chan, Benny K K; Xu, Guang; Kim, Hyun Kyong; Park, Jin-Ho; Kim, Won

2018-01-01

Corals and their associated fauna are extremely diverse in tropical waters and form major reefs. In the high-latitude temperate zone, corals living near their distribution limit are considered marginal communities because they are particularly extremely sensitive to environmental and climatic changes. In this study, we examined the diversity and host usage of coral-associated barnacles on Jeju Island, Korea, the northern coral distribution limit in the East China Sea. In this study, only three coral-associated barnacles-from two genera in two subfamilies-were collected. The Pyrgomatinid barnacles Cantellius arcuatus and Cantellius cf. euspinulosum were found only on the corals Montipora millepora and Alveopora japonica, respectively. The Megatrematinid barnacle Pyrgomina oulastreae, relatively a generalist, was found on Psammocora spp. (both profundacella and albopicta) and Oulastrea crispata corals. The host usage of these three barnacles does not overlap. DNA barcode sequences of the C. arcuatus specimens collected in the present study matched those collected in Kochi in Japan, Taiwan, Malaysia and Papua New Guinea, suggesting that this species has a wide geographical distribution. C. arcuatus covers a wider host range in Taiwan waters, inhabiting Montipora spp. and Porites spp., which suggests that the host specificity of coral-associated barnacles varies with host availability. C. cf. euspinulosum probably has a very narrow distribution and host usage. The sequences of C. cf. euspinulosum on Jeju Island do not match those of any known sequences of Cantellius barnacles in the Indo-Pacific region. P. oulastreae probably prefers cold water because it has been reported in temperate regions. Coral-associated barnacles in marginal communities have considerably lower diversity than their subtropical and tropical counterparts. When host availability is limited, marginal coral-associated barnacles exhibit higher host specificity than those in subtropical and tropical

Effects of offshore oil drilling on Philippine reef corals.

USGS Publications Warehouse

Hudson, J.H.; Shinn, E.A.; Robbin, D.M.

1982-01-01

An offshore drilling site in an area of extensive live-coral bottom off NW Palawan Island, Philippines, was examined 15 months after well completion. Porites lutea growth rates showed that little suppression of head coral growth could be attributed to drilling. Diver observation, however, together with analysis of sampling transect photomosaics, revealed 70-90% reduction in foliose, branching, and plate-like corals in an iron-stained area that extended out from the wellheads in a 115 X 85-m ellipse.-from Authors

In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event.

PubMed

Monroe, Alison A; Ziegler, Maren; Roik, Anna; Röthig, Till; Hardenstine, Royale S; Emms, Madeleine A; Jensen, Thor; Voolstra, Christian R; Berumen, Michael L

2018-01-01

Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the "3rd global coral bleaching event" by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (<1% of coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen.

Gross and microscopic pathology of hard and soft corals in New Caledonia

USGS Publications Warehouse

Work, Thierry M.; Aeby, Greta S.; Lasne, Gregory; Tribollet, Aline

2014-01-01

We surveyed the reefs of Grande Terre, New Caledonia, for coral diseases in 2010 and 2013. Lesions encountered in hard and soft corals were systematically described at the gross and microscopic level. We sampled paired and normal tissues from 101 and 65 colonies in 2010 and 2013, respectively, comprising 51 species of corals from 27 genera. Tissue loss was the most common gross lesion sampled (40%) followed by discoloration (28%), growth anomalies (13%), bleaching (10%), and flatworm infestation (1%). When grouped by gross lesions, the diversity of microscopic lesions as measured by Shannon–Wiener index was highest for tissue loss, followed by discoloration, bleaching, and growth anomaly. Our findings document an extension of the range of certain diseases such as Porites trematodiasis and endolithic hypermycosis (dark spots) to the Western Pacific as well as the presence of a putative cnidarian endosymbiont. We also expand the range of species infected by cell-associated microbial aggregates, and confirm the trend that these aggregates predominate in dominant genera of corals in the Indo-Pacific. This study highlights the importance of including histopathology as an integral component of baseline coral disease surveys, because a given gross lesion might be associated with multiple potential causative agents.

Chronic and catastrophic natural mortality of three common Caribbean reef corals

NASA Astrophysics Data System (ADS)

Bythell, J. C.; Gladfelter, E. H.; Bythell, M.

1993-11-01

Compared to catastrophic impacts from storms, disease epidemics and bleaching events, little is known about the effects of more routine chronic mortality in reef corals. To monitor this ongoing mortality, monthly visual assessments of the cause of tissue damage were related to mortality rates (changes in planar surface area) of tagged colonies of three common reef corals: Montastrea annularis, Porites astreoides and Diploria strigosa at Buck Island Reef National Monument, St. Croix, US Virgin Islands. During the study Hurricane Hugo, the most powerful cyclone to affect the area in at least 60 y, made a direct impact on the site. Effects of the hurricane were extremely localized, with certain exposed sites being almost completely razed while others showed no detectable changes in community structure. Mortality caused both by the hurricane and by other factors during the 26 month study varied between species and also between site locations around the island. Differences in susceptibility were not dependent solely on gross morphology, because two robust, massive species showed opposite responses to hurricane damage and chronic mortality. Diploria strigosa was virtually unaffected by chronic factors, but was heavily damaged at exposed sites during the hurricane. In contrast, mortality from predation and tissue necrosis was high in Montastrea annularis, but it largely escaped damage from the hurricane because it was absent from the most severely scoured locations. Porites astreoides, with populations dominated by much smaller colonies, was affected by both chronic and hurricanerelated mortality. Differences in susceptibility to the various types of natural disturbance among species, coupled with high spatial and temporal variability in the effects of such disturbances, may be critical to the maintenance of species diversity on the reef.

Growth rates of Porites astreoides and Orbicella franksi in mesophotic habitats surrounding St. Thomas, US Virgin Islands

NASA Astrophysics Data System (ADS)

Groves, Sarah H.; Holstein, Daniel M.; Enochs, Ian C.; Kolodzeij, Graham; Manzello, Derek P.; Brandt, Marilyn E.; Smith, Tyler B.

2018-06-01

Mesophotic coral ecosystems (MCEs) are deep (> 30 m), light-dependent communities that are abundant in many parts of the global ocean. MCEs are potentially connected to shallow reefs via larval exchange and may act as refuges for reef organisms. However, MCE community level recovery after disturbance, and thus, community resilience, are poorly understood components of their capacity as refuges. To assess the potential for disturbance and growth to drive community structure on MCEs with differential biophysical conditions and coral communities, we collected colonies of Orbicella franksi and Porites astreoides and used computerized tomography to quantify calcification. The divergence of coral growth rates in MCEs with different environmental conditions may be species specific; habitat-forming O. franksi have slow and consistent growth rates of 0.2 cm yr-1 below 30 m, regardless of mesophotic habitat, compared to 1.0 cm yr-1 in shallow-water habitats. Slow skeletal growth rates in MCEs suggest that rates of recovery from disturbance will likely also be slow. Localized buffering of MCEs from the stressors affecting shallow reefs is therefore crucial to the long-term capacity of these sites to serve as refugia, given that skeletal extension and recovery from disturbance in MCEs will be significantly slower than on shallow reefs.

Identification of Scleractinian Coral Recruits Using Fluorescent Censusing and DNA Barcoding Techniques

PubMed Central

Hsu, Chia-Min; de Palmas, Stéphane; Kuo, Chao-Yang; Denis, Vianney; Chen, Chaolun Allen

2014-01-01

The identification of coral recruits has been problematic due to a lack of definitive morphological characters being available for higher taxonomic resolution. In this study, we tested whether fluorescent detection of coral recruits used in combinations of different DNA-barcoding markers (cytochrome oxidase I gene [COI], open reading frame [ORF], and nuclear Pax-C intron [PaxC]) could be useful for increasing the resolution of coral spat identification in ecological studies. One hundred and fifty settlement plates were emplaced at nine sites on the fringing reefs of Kenting National Park in southern Taiwan between April 2011 and September 2012. A total of 248 living coral spats and juveniles (with basal areas ranging from 0.21 to 134.57 mm2) were detected on the plates with the aid of fluorescent light and collected for molecular analyses. Using the COI DNA barcoding technique, 90.3% (224/248) of coral spats were successfully identified into six genera, including Acropora, Isopora, Montipora, Pocillopora, Porites, and Pavona. PaxC further separated I. cuneata and I. palifera of Isopora from Acropora, and ORF successfully identified the species of Pocillopora (except P. meandrina and P. eydouxi). Moreover, other cnidarian species such as actinarians, zoanthids, and Millepora species were visually found using fluorescence and identified by COI DNA barcoding. This combination of existing approaches greatly improved the taxonomic resolution of early coral life stages, which to date has been mainly limited to the family level based on skeletal identification. Overall, this study suggests important improvements for the identification of coral recruits in ecological studies. PMID:25211345

Identification of scleractinian coral recruits using fluorescent censusing and DNA barcoding techniques.

PubMed

Hsu, Chia-Min; de Palmas, Stéphane; Kuo, Chao-Yang; Denis, Vianney; Chen, Chaolun Allen

2014-01-01

The identification of coral recruits has been problematic due to a lack of definitive morphological characters being available for higher taxonomic resolution. In this study, we tested whether fluorescent detection of coral recruits used in combinations of different DNA-barcoding markers (cytochrome oxidase I gene [COI], open reading frame [ORF], and nuclear Pax-C intron [PaxC]) could be useful for increasing the resolution of coral spat identification in ecological studies. One hundred and fifty settlement plates were emplaced at nine sites on the fringing reefs of Kenting National Park in southern Taiwan between April 2011 and September 2012. A total of 248 living coral spats and juveniles (with basal areas ranging from 0.21 to 134.57 mm(2)) were detected on the plates with the aid of fluorescent light and collected for molecular analyses. Using the COI DNA barcoding technique, 90.3% (224/248) of coral spats were successfully identified into six genera, including Acropora, Isopora, Montipora, Pocillopora, Porites, and Pavona. PaxC further separated I. cuneata and I. palifera of Isopora from Acropora, and ORF successfully identified the species of Pocillopora (except P. meandrina and P. eydouxi). Moreover, other cnidarian species such as actinarians, zoanthids, and Millepora species were visually found using fluorescence and identified by COI DNA barcoding. This combination of existing approaches greatly improved the taxonomic resolution of early coral life stages, which to date has been mainly limited to the family level based on skeletal identification. Overall, this study suggests important improvements for the identification of coral recruits in ecological studies.

Community change and evidence for variable warm-water temperature adaptation of corals in Northern Male Atoll, Maldives.

PubMed

McClanahan, T R; Muthiga, N A

2014-03-15

This study provides a descriptive analysis of the North Male, Maldives seven years after the 1998 bleaching disturbance to determine the state of the coral community composition, the recruitment community, evidence for recovery, and adaptation to thermal stress. Overall, hard coral cover recovered at a rate commonly reported in the literature but with high spatial variability and shifts in taxonomic composition. Massive Porites, Pavona, Synarea, and Goniopora were unusually common in both the recruit and adult communities. Coral recruitment was low and some coral taxa, namely Tubipora, Seriatopora, and Stylophora, were rarer than expected. A study of the bleaching response to a thermal anomaly in 2005 indicated that some taxa, including Leptoria, Platygyra, Favites, Fungia, Hydnophora, and Galaxea astreata, bleached as predicted while others, including Acropora, Pocillopora, branching Porites, Montipora, Stylophora, and Alveopora, bleached less than predicted. This indicates variable-adaptation potentials among the taxa and considerable potential for ecological reorganization of the coral community. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physiological and isotopic responses of scleractinian corals to ocean acidification

NASA Astrophysics Data System (ADS)

Krief, Shani; Hendy, Erica J.; Fine, Maoz; Yam, Ruth; Meibom, Anders; Foster, Gavin L.; Shemesh, Aldo

2010-09-01

Uptake of anthropogenic CO 2 by the oceans is altering seawater chemistry with potentially serious consequences for coral reef ecosystems due to the reduction of seawater pH and aragonite saturation state ( Ωarag). The objectives of this long-term study were to investigate the viability of two ecologically important reef-building coral species, massive Porites sp. and Stylophora pistillata, exposed to high pCO 2 (or low pH) conditions and to observe possible changes in physiologically related parameters as well as skeletal isotopic composition. Fragments of Porites sp. and S. pistillata were kept for 6-14 months under controlled aquarium conditions characterized by normal and elevated pCO 2 conditions, corresponding to pH T values of 8.09, 7.49, and 7.19, respectively. In contrast with shorter, and therefore more transient experiments, the long experimental timescale achieved in this study ensures complete equilibration and steady state with the experimental environment and guarantees that the data provide insights into viable and stably growing corals. During the experiments, all coral fragments survived and added new skeleton, even at seawater Ωarag < 1, implying that the coral skeleton is formed by mechanisms under strong biological control. Measurements of boron (B), carbon (C), and oxygen (O) isotopic composition of skeleton, C isotopic composition of coral tissue and symbiont zooxanthellae, along with physiological data (such as skeletal growth, tissue biomass, zooxanthellae cell density, and chlorophyll concentration) allow for a direct comparison with corals living under normal conditions and sampled simultaneously. Skeletal growth and zooxanthellae density were found to decrease, whereas coral tissue biomass (measured as protein concentration) and zooxanthellae chlorophyll concentrations increased under high pCO 2 (low pH) conditions. Both species showed similar trends of δ 11B depletion and δ 18O enrichment under reduced pH, whereas the δ 13C results

Contrasting evolutionary patterns in two reef-corals and their possible relationship to life history traits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, A.B.

1985-01-01

Multivariate statistical analyses have been used to redefine species within two genera of reef-corals (Porites and Montastraea) and to trace their evolutionary patterns through a continuous sequence from late Miocene to early Pliocene time. The material studied consists of populations sampled at regular intervals through four stratigraphic sections in the northern Dominican Republic. The results show that species in the first genus (Porites) have relatively short durations, morphologic stability, and narrow spatial distributions. Their overall evolutionary history is characterized by short periods of radiation and widespread extinction, separated by longer periods of stasis. In contrast, species in the second genusmore » (Montastraea) exhibit various different durations and distributions and directional morphologic trends. These differences in patterns may be related to the dissimilar life histories of the two genera. Patterns in the first genus appear more common in organisms having high larval recruitment, high mortality, high genetic variation, and less morphologic distance between species. Patterns in the second genus occur more frequently in slower growing, phenotypically plastic organisms experiencing less recruitment and mortality and showing more morphologic distance between species.« less

Diversity in skeletal architecture influences biological heterogeneity and Symbiodinium habitat in corals.

PubMed

Yost, Denise M; Wang, Li-Hsueh; Fan, Tung-Yung; Chen, Chii-Shiarng; Lee, Raymond W; Sogin, Emilia; Gates, Ruth D

2013-10-01

Scleractinian corals vary in response to rapid shifts in the marine environment and changes in reef community structure post-disturbance reveal a clear relationship between coral performance and morphology. With exceptions, massive corals are thought to be more tolerant and branching corals more vulnerable to changing environmental conditions, notably thermal stress. The typical responses of massive and branching coral taxa, respectively, are well documented; however, the biological and functional characteristics that underpin this variation are not well understood. We address this gap by comparing multiple biological attributes that are correlated with skeletal architecture in two perforate (having porous skeletal matrices with intercalating tissues) and two imperforate coral species (Montipora aequituberculata, Porites lobata, Pocillopora damicornis, and Seriatopora hystrix) representing three morphotypes. Our results reveal inherent biological heterogeneity among corals and the potential for perforate skeletons to create complex, three-dimensional internal habitats that impact the dynamics of the symbiosis. Patterns of tissue thickness are correlated with the concentration of symbionts within narrow regions of tissue in imperforate corals versus broad distribution throughout the larger tissue area in perforate corals. Attributes of the perforate and environmentally tolerant P. lobata were notable, with tissues ∼5 times thicker than in the sensitive, imperforate species P. damicornis and S. hystrix. Additionally, P. lobata had the lowest baseline levels of superoxide and Symbiodinium that provisioned high levels of energy. Given our observations, we hypothesize that the complexity of the visually obscured internal environment has an impact on host-symbiont dynamics and ultimately on survival, warranting further scientific investigation. Copyright © 2013 Elsevier GmbH. All rights reserved.

Variability in the effects of macroalgae on the survival and growth of corals: the consumer connection.

PubMed

Bulleri, Fabio; Couraudon-Réale, Marine; Lison de Loma, Thierry; Claudet, Joachim

2013-01-01

Shifts in dominance from corals to macroalgae are occurring in many coral reefs worldwide. Macroalgal canopies, while competing for space with coral colonies, may also form a barrier to herbivorous and corallivorous fish, offering protection to corals. Thus, corals could either suffer from enhanced competition with canopy-forming and understorey macroalgae or benefit from predator exclusion. Here, we tested the hypothesis that the effects of the brown, canopy-forming macroalga, Turbinaria ornata, on the survival and growth of corals can vary according to its cover, to the presence or absence of herbivorous and corallivorous fish and to the morphological types of corals. Over a period of 66 days, two coral species differing in growth form, Acropora pulchra and Porites rus, were exposed to three different covers of T. ornata (absent versus medium versus high), in the presence or absence of fish. Irrespective of the cover of T. ornata, fish exclusion reduced mortality rates of A. pulchra. Following fish exclusion, a high cover of T. ornata depressed the growth of this branched coral, whilst it had no effect when fish species were present. P. rus suffered no damage from corallivorous fish, but its growth was decreased by high covers of T. ornata, irrespective of the presence or absence of fish. These results show that negative effects of T. ornata on some coral species are subordinate to those of fish predation and are, therefore, likely to manifest only on reefs severely depleted of predators. In contrast, space dominance by T. ornata may decrease the growth of other coral species regardless of predation intensity. In general, this study shows that susceptibility to predation may determine the severity of the effects of canopy-forming macroalgae on coral growth.

In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event

PubMed Central

Ziegler, Maren; Roik, Anna; Röthig, Till; Hardenstine, Royale S.; Emms, Madeleine A.; Jensen, Thor; Voolstra, Christian R.; Berumen, Michael L.

2018-01-01

Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the “3rd global coral bleaching event” by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (<1% of coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen. PMID:29672556

Effects of thermal stress and nitrate enrichment on the larval performance of two Caribbean reef corals

NASA Astrophysics Data System (ADS)

Serrano, Xaymara M.; Miller, Margaret W.; Hendee, James C.; Jensen, Brittany A.; Gapayao, Justine Z.; Pasparakis, Christina; Grosell, Martin; Baker, Andrew C.

2018-03-01

The effects of multiple stressors on the early life stages of reef-building corals are poorly understood. Elevated temperature is the main physiological driver of mass coral bleaching events, but increasing evidence suggests that other stressors, including elevated dissolved inorganic nitrogen (DIN), may exacerbate the negative effects of thermal stress. To test this hypothesis, we investigated the performance of larvae of Orbicella faveolata and Porites astreoides, two important Caribbean reef coral species with contrasting reproductive and algal transmission modes, under increased temperature and/or elevated DIN. We used a fluorescence-based microplate respirometer to measure the oxygen consumption of coral larvae from both species, and also assessed the effects of these stressors on P. astreoides larval settlement and mortality. Overall, we found that (1) larvae increased their respiration in response to different factors ( O. faveolata in response to elevated temperature and P. astreoides in response to elevated nitrate) and (2) P. astreoides larvae showed a significant increase in settlement as a result of elevated nitrate, but higher mortality under elevated temperature. This study shows how microplate respirometry can be successfully used to assess changes in respiration of coral larvae, and our findings suggest that the effects of thermal stress and nitrate enrichment in coral larvae may be species specific and are neither additive nor synergistic for O. faveolata or P. astreoides. These findings may have important consequences for the recruitment and community reassembly of corals to nutrient-polluted reefs that have been impacted by climate change.

[Taxonomy and distribution of the hermatypic corals (Scleractinia) of the Revillagigedo Archipelago, Mexico].

PubMed

Ketchum, J T; Reyes Bonilla, H

2001-01-01

In spite of some recent detailed accounts about the scleractinian corals of the Archipiélago de Revillagigedo, taxonomic work on this fauna has been sparse. Consequently, solid taxonomic background is needed, especially to support further studies at community level. During five field trips (between 1990 and 1995) collections were made at different depths on three of the archipelago islands: Socorro, Clarión and San Benedicto. A total of 250 specimens were collected. Coral identifications were made using co-occurrence methods concomitant with their descriptions, diagnosis and illustrations from a number of publications, and with morphological analysis. Coral distributions were taken from literature. Twenty-two species of zooxanthellate scleractinian corals are described, with their local and world-wide geographic distribution, and each illustrated with macro and microphotographs. Keys to the genera and species of the archipelago are also included. Porites and Pocillopora exhibit the highest species richness with a great intraspecific variation, as well as a number of morphological convergences within and between species which form species complexes, and several new species and morphs. Clarion, the oldest and most isolated island of the archipelago, harbors a number of coral morphs that are probable new species. More than half of the species found at the Revillagigedos are distributed exclusively on oceanic islands of the eastern Pacific and close to one third exist only at this archipelago. The Revillagigedos have strong faunal similarities and share a number of endemics with Clipperton Atoll, all of which support the idea that these islands constitute a separate biogeographic subregion within the eastern Pacific. Lastly, the present document substantiates the hypothesis that the Revillagigedos are important stepping-stone islands for the migration of in-shore marine species from the Central to the eastern Pacific.

Linking sewage pollution and water quality to spatial patterns of Porites lobata growth anomalies in Puako, Hawaii.

PubMed

Yoshioka, Reyn M; Kim, Catherine J S; Tracy, Allison M; Most, Rebecca; Harvell, C Drew

2016-03-15

Sewage pollution threatens the health of coastal populations and ecosystems, including coral reefs. We investigated spatial patterns of sewage pollution in Puako, Hawaii using enterococci concentrations and δ(15)N Ulva fasciata macroalgal bioassays to assess relationships with the coral disease Porites lobata growth anomalies (PGAs). PGA severity and enterococci concentrations were high, spatially variable, and positively related. Bioassay algal δ(15)N showed low sewage pollution at the reef edge while high values of resident algae indicated sewage pollution nearshore. Neither δ(15)N metric predicted PGA measures, though bioassay δ(15)N was negatively related to coral cover. Furthermore, PGA prevalence was much higher than previously recorded in Hawaii and the greater Indo-Pacific, highlighting Puako as an area of concern. Although further work is needed to resolve the relationship between sewage pollution and coral cover and disease, these results implicate sewage pollution as a contributor to diminished reef health. Copyright © 2016 Elsevier Ltd. All rights reserved.

No gene flow across the Eastern Pacific Barrier in the reef-building coral Porites lobata.

PubMed

Baums, Iliana B; Boulay, Jennifer N; Polato, Nicholas R; Hellberg, Michael E

2012-11-01

The expanse of deep water between the central Pacific islands and the continental shelf of the Eastern Tropical Pacific is regarded as the world's most potent marine biogeographic barrier. During recurrent climatic fluctuations (ENSO, El Niño Southern Oscillation), however, changes in water temperature and the speed and direction of currents become favourable for trans-oceanic dispersal of larvae from central Pacific to marginal eastern Pacific reefs. Here, we investigate the population connectivity of the reef-building coral Porites lobata across the Eastern Pacific Barrier (EPB). Patterns of recent gene flow in samples (n = 1173) from the central Pacific and the Eastern Tropical Pacific (ETP) were analysed with 12 microsatellite loci. Results indicated that P. lobata from the ETP are strongly isolated from those in the central Pacific and Hawaii (F(ct) ' = 0.509; P < 0.001). However, samples from Clipperton Atoll, an oceanic island on the eastern side of the EPB, grouped with the central Pacific. Within the central Pacific, Hawaiian populations were strongly isolated from three co-occurring clusters found throughout the remainder of the central Pacific. No further substructure was evident in the ETP. Changes in oceanographic conditions during ENSO over the past several thousand years thus appear insufficient to support larval deliveries from the central Pacific to the ETP or strong postsettlement selection acts on ETP settlers from the central Pacific. Recovery of P. lobata populations in the frequently disturbed ETP thus must depend on local larval sources. © 2012 Blackwell Publishing Ltd.

Mechanisms of interaction between macroalgae and scleractinians on a coral reef in Jamaica.

PubMed

River, G F.; Edmunds, P J.

2001-07-01

After several decades of disturbance, many coral reefs in the Caribbean are dominated by macroalgae. One process affecting this transition is coral-macroalgal competition, yet few studies have addressed the mechanisms involved. In this study, we investigated competition between the tall and bushy macroalga Sargassum hystrix (J. Agardh) and the branching coral Porites porites (Pallas) on a shallow reef in Jamaica. Experiments were designed to expose coral branches to different treatments to test the role of shading and abrasion by Sargassum on coral growth and polyp expansion. Corals exposed to Sargassum grew significantly more slowly (80% reduction) than controls, but this effect was absent when corals were caged to prevent physical contact with macroalgae. Light levels were reduced in both the algal and cage treatments, but shading apparently had little effect on the growth of corals in cages. Short-term measurements of integrated net water flow did not detect variation among treatments. In algal-mimic treatments, where clear plastic strips could touch but not shade the corals, growth rates were 25% lower than controls, but this effect was not statistically significant. Thus, the growth of corals in contact with Sargassum was reduced by abrasion and, to a lesser extent, by factors unique to living macroalgae. Analysis of polyp expansion showed that polyps were more frequently retracted when corals were in contact with macroalgae or algal-mimics compared to controls or cage treatment; the frequency of polyp contraction was correlated positively with growth. Together, these results suggest that abrasion-mediated polyp retraction is one of the primary mechanisms of competition utilized by tall (ca. 17 cm) macroalgae against scleractinian corals.

Comparative embryology of eleven species of stony corals (Scleractinia).

PubMed

Okubo, Nami; Mezaki, Takuma; Nozawa, Yoko; Nakano, Yoshikatsu; Lien, Yi-Ting; Fukami, Hironobu; Hayward, David C; Ball, Eldon E

2013-01-01

A comprehensive understanding of coral reproduction and development is needed because corals are threatened in many ways by human activity. Major threats include the loss of their photosynthetic symbionts (Symbiodinium) caused by rising temperatures (bleaching), reduced ability to calcify caused by ocean acidification, increased storm severity associated with global climate change and an increase in predators caused by runoff from human agricultural activity. In spite of these threats, detailed descriptions of embryonic development are not available for many coral species. The current consensus is that there are two major groups of stony corals, the "complex" and the "robust". In this paper we describe the embryonic development of four "complex" species, Pseudosiderastrea tayamai, Galaxea fascicularis, Montipora hispida, and Pavona Decussata, and seven "robust" species, Oulastrea crispata, Platygyra contorta, Favites abdita, Echinophyllia aspera, Goniastrea favulus, Dipsastraea speciosa (previously Favia speciosa), and Phymastrea valenciennesi (previously Montastrea valenciennesi). Data from both histologically sectioned embryos and whole mounts are presented. One apparent difference between these two major groups is that before gastrulation the cells of the complex corals thus far described (mainly Acropora species) spread and flatten to produce the so-called prawn chip, which lacks a blastocoel. Our present broad survey of robust and complex corals reveals that prawn chip formation is not a synapomorphy of complex corals, as Pavona Decussata does not form a prawn chip and has a well-developed blastocoel. Although prawn chip formation cannot be used to separate the two clades, none of the robust corals which we surveyed has such a stage. Many robust coral embryos pass through two periods of invagination, separated by a return to a spherical shape. However, only the second of these periods is associated with endoderm formation. We have therefore termed the first

Comparative Embryology of Eleven Species of Stony Corals (Scleractinia)

PubMed Central

Okubo, Nami; Mezaki, Takuma; Nozawa, Yoko; Nakano, Yoshikatsu; Lien, Yi-Ting; Fukami, Hironobu; Hayward, David C.; Ball, Eldon E.

2013-01-01

A comprehensive understanding of coral reproduction and development is needed because corals are threatened in many ways by human activity. Major threats include the loss of their photosynthetic symbionts (Symbiodinium) caused by rising temperatures (bleaching), reduced ability to calcify caused by ocean acidification, increased storm severity associated with global climate change and an increase in predators caused by runoff from human agricultural activity. In spite of these threats, detailed descriptions of embryonic development are not available for many coral species. The current consensus is that there are two major groups of stony corals, the "complex" and the "robust". In this paper we describe the embryonic development of four "complex" species, Pseudosiderastrea tayamai, Galaxea fascicularis, Montipora hispida, and Pavona Decussata, and seven "robust" species, Oulastrea crispata, Platygyra contorta, Favites abdita, Echinophyllia aspera, Goniastrea favulus, Dipsastraea speciosa (previously Favia speciosa), and Phymastrea valenciennesi (previously Montastrea valenciennesi). Data from both histologically sectioned embryos and whole mounts are presented. One apparent difference between these two major groups is that before gastrulation the cells of the complex corals thus far described (mainly Acropora species) spread and flatten to produce the so-called prawn chip, which lacks a blastocoel. Our present broad survey of robust and complex corals reveals that prawn chip formation is not a synapomorphy of complex corals, as Pavona Decussata does not form a prawn chip and has a well-developed blastocoel. Although prawn chip formation cannot be used to separate the two clades, none of the robust corals which we surveyed has such a stage. Many robust coral embryos pass through two periods of invagination, separated by a return to a spherical shape. However, only the second of these periods is associated with endoderm formation. We have therefore termed the first

Coral reproduction in Western Australia

PubMed Central

Speed, Conrad W.; Babcock, Russ

2016-01-01

the full moon. The timing of the full moon determined whether spawning was split over two months, which was common on tropical reefs. There were few data available for non-Acropora corals, which may have different patterns of reproduction. For example, the massive Porites seemed to spawn through spring to autumn on Kimberley Oceanic reefs and during summer in the Pilbara region, where other common corals (e.g. Turbinaria & Pavona) also displayed different patterns of reproduction to the Acropora. The brooding corals (Isopora & Seriatopora) on Kimberley Oceanic reefs appeared to planulate during many months, possibly with peaks from spring to autumn; a similar pattern is likely on other WA reefs. Gaps in knowledge were also due to the difficulty in identifying species and issues with methodology. We briefly discuss some of these issues and suggest an approach to quantifying variation in reproductive output throughout a year. PMID:27231651

Extended geographic distribution of several Indo-Pacific coral reef diseases.

PubMed

Weil, E; Irikawa, A; Casareto, B; Suzuki, Y

2012-03-20

Other than coral bleaching, few coral diseases or diseases of other reef organisms have been reported from Japan. This is the first report of lesions similar to Porites ulcerative white spots (PUWS), brown band disease (BrB), pigmentation response (PR), and crustose coralline white syndrome (CCWS) for this region. To assess the health status and disease prevalence, qualitative and quantitative surveys (3 belt transects of 100 m² each on each reef) were performed in March and September 2010 on 2 reefs of the Ginowan-Ooyama reef complex off Okinawa, and 2 protected reefs off Zamani Island, in the Kerama Islands 40 km west of Okinawa. Overall, mean (±SD) disease prevalence was higher in Ginowan-Ooyama (9.7 ± 7.9%) compared to Zamami (3.6 ± 4.6%). Porites lutea was most affected by PUWS at Ooyama (23.1 ± 10.4 vs. 4.5 ± 5.2%). White syndrome (WS) mostly affected Acropora cytherea (12. 5 ± 18.0%) in Zamami and Oxipora lacera (10.2 ± 10%) in Ooyama. Growth anomalies (GA) and BrB were only observed on A. cytherea (8.3 ± 6.2%) and A. nobilis (0.8%) at Zamami. Black band disease affected Pachyseris speciosa (6.0 ± 4.6%) in Ooyama only. Pigmentation responses (PR) were common in massive Porites in both localities (2.6 ± 1.9 and 5.6 ± 2.3% respectively). Crustose coralline white syndrome (CCWS) was observed in both localities. These results significantly expand the geographic distribution of PUWS, BrB, PR and CCWS in the Indo-Pacific, indicating that the northernmost coral reefs in the western Pacific are susceptible to a larger number of coral diseases than previously thought.

Temporal and taxonomic contrasts in coral growth at Davies Reef, central Great Barrier Reef, Australia

NASA Astrophysics Data System (ADS)

Anderson, Kristen D.; Cantin, Neal E.; Heron, Scott F.; Lough, Janice M.; Pratchett, Morgan S.

2018-06-01

Demographic processes, such as growth, can have an important influence on the population and community structure of reef-building corals. Importantly, ongoing changes in environmental conditions (e.g. ocean warming) are expected to affect coral growth, contributing to changes in the structure of coral populations and communities. This study quantified contemporary growth rates (linear extension and calcification) for the staghorn coral, Acropora muricata, at Davies Reef, central Great Barrier Reef, Australia. Growth rates were measured at three different depths (5, 10, and 15 m) over 2 yr (2012-2014) assessing both seasonal and inter-annual variability. Results of this study were compared to equivalent measurements made in 1980-1982 at the same location. To assist in understanding inter-annual variability in coral growth, we also examined annual growth bands from massive Porites providing continuous growth and records of flooding history for Davies Reef over the period 1979-2012. Linear extension rates of A. muricata were substantially (11-62%) lower in 2012-2014 compared to 1980-1982, especially at 10 and 15 m depths. These declines in growth coincide with a + 0.14 °C change in annual mean temperature. For massive Porites, however, calcification rates were highly variable among years and there was no discernible long-term change in growth despite sustained increases in temperature of 0.064 °C per decade. Apparent differences in the growth rates of Acropora between 1980-1982 and 2012-2014 may reflect inter-annual variation in coral growth (as seen for massive Porites), though it is known branching Acropora is much more sensitive to changing environmental conditions than massive corals. There are persistent issues in assessing the sensitivities of branching corals to environmental change due to limited capacity for retrospective analyses of growth, but given their disproportionate contribution to habitat complexity and reef structure, it is critical to ascertain

Sibling species in Montastraea annularis, coral bleaching, and the coral climate record

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knowlton, N.; Weil, E.; Weigt, L.A.

1992-01-17

Measures of growth and skeletal isotopic ratios in the Caribbean coral Montastraea annularis are fundamental to many studies of paleoceanography, environmental degradation, and global climate change. This taxon is shown to consist of at least three sibling species in shallow water. The two most commonly studied of these show highly significant differences in growth rate and oxygen isotopic ratios, parameters routinely used to estimate past climatic conditions; unusual coloration in the third may have confused research on coral bleaching. Interpretation or comparison of past and current studies can be jeopardized by ignoring these species boundaries.

Dongsha Atoll: A potential thermal refuge for reef-building corals in the South China Sea.

PubMed

Tkachenko, Konstantin S; Soong, Keryea

2017-06-01

Dongsha Atoll (also known as the Pratas Islands), the northernmost atoll in the South China Sea, experiences two contrasting physical phenomena: repetitive anomalies of the sea surface temperature exceeding the coral bleaching threshold and regular effects of the world's strongest internal waves resulting in the rhythmic upwelling of cold deep waters at the outer reef slopes of the atoll. This unique combination may result in significant differences in coral species composition and structure between the lagoon and forereef. Surveys conducted in August-September 2016 at 12 study sites in the 2-15 m depth range at Dongsha Atoll revealed a clear spatial separation between 'thermally-susceptible' stony coral genera, including Acropora, Pocillopora and Montipora, which mainly inhabited the forereef, and 'thermally-resistant' genera, including massive Porites, foliaceous Echinopora, Pavona and Turbinaria, which mainly resided in the lagoon. The mean coral cover and species richness on the forereef were respectively 1.8 and 1.4 times higher than those in the lagoon (61.3% and 98 species on the forereef vs. 34.2% and 69 species in the lagoon). Coral mortality rates, expressed as the ratio of dead to live stony corals, showed the same pattern (0.4 in the lagoon vs. 0.009 on the forereef). Furthermore, in a laboratory experiment, 'thermally-susceptible' taxa from the lagoon, (e.g. Pocillopora verrucosa and P. damicornis), exhibited higher resistance to bleaching than did their counterparts from the forereef. The present findings indicate that Dongsha Atoll is a potential thermal refuge for reef-building corals in the northern South China Sea and reveal the development of resilience and resistance to bleaching in coral communities of the lagoon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coral oxygen isotope records of interdecadal climate variations in the South Pacific Convergence Zone region

NASA Astrophysics Data System (ADS)

Bagnato, Stefan; Linsley, Braddock K.; Howe, Stephen S.; Wellington, Gerard M.; Salinger, Jim

2005-06-01

The South Pacific Convergence Zone (SPCZ), a region of high rainfall, is a major feature of subtropical Southern Hemisphere climate and contributes to and interacts with circulation features across the Pacific, yet its past temporal variability and forcing remain only partially understood. Here we compare coral oxygen isotopic (δ18O) series (spanning A.D. 1997-1780 and A.D. 2001-1776) from two genera of hermatypic corals in Fiji, located within the SPCZ, to examine the fidelity of these corals in recording climate change and SPCZ interdecadal dynamics. One of these coral records is a new 225-year subannually resolved δ18O series from the massive coral Diploastreaheliopora. Diploastrea's use in climate reconstructions is still relatively new, but this coral has shown encouragingly similar interannual variability to Porites, the coral genus most commonly used in Pacific paleoclimate studies. In Fiji we observe that interdecadal δ18O variance is also similar in these two coral genera, and Diploastrea contains a larger-amplitude interdecadal signal that more closely tracks instrumental-based indices of Pacific interdecadal climate change and the SPCZ than Porites. Both coral δ18O series record greater interdecadal variability from ˜1880 to 1950, which is consistent with the observations of Folland et al. (2002), who reported higher variability in SPCZ position before 1945. These observations indicate that Diploastrea will likely provide a significant new source of long-term climate information from the SPCZ region.

Satellite SST-Based Coral Disease Outbreak Predictions for the Hawaiian Archipelago.

PubMed

Caldwell, Jamie M; Heron, Scott F; Eakin, C Mark; Donahue, Megan J

2016-02-01

Predicting wildlife disease risk is essential for effective monitoring and management, especially for geographically expansive ecosystems such as coral reefs in the Hawaiian archipelago. Warming ocean temperature has increased coral disease outbreaks contributing to declines in coral cover worldwide. In this study we investigated seasonal effects of thermal stress on the prevalence of the three most widespread coral diseases in Hawai'i: Montipora white syndrome, Porites growth anomalies and Porites tissue loss syndrome. To predict outbreak likelihood we compared disease prevalence from surveys conducted between 2004 and 2015 from 18 Hawaiian Islands and atolls with biotic (e.g., coral density) and abiotic (satellite-derived sea surface temperature metrics) variables using boosted regression trees. To date, the only coral disease forecast models available were developed for Acropora white syndrome on the Great Barrier Reef (GBR). Given the complexities of disease etiology, differences in host demography and environmental conditions across reef regions, it is important to refine and adapt such models for different diseases and geographic regions of interest. Similar to the Acropora white syndrome models, anomalously warm conditions were important for predicting Montipora white syndrome, possibly due to a relationship between thermal stress and a compromised host immune system. However, coral density and winter conditions were the most important predictors of all three coral diseases in this study, enabling development of a forecasting system that can predict regions of elevated disease risk up to six months before an expected outbreak. Our research indicates satellite-derived systems for forecasting disease outbreaks can be appropriately adapted from the GBR tools and applied for a variety of diseases in a new region. These models can be used to enhance management capacity to prepare for and respond to emerging coral diseases throughout Hawai'i and can be modified

Satellite SST-Based Coral Disease Outbreak Predictions for the Hawaiian Archipelago

PubMed Central

Caldwell, Jamie M.; Heron, Scott F.; Eakin, C. Mark; Donahue, Megan J.

2017-01-01

Predicting wildlife disease risk is essential for effective monitoring and management, especially for geographically expansive ecosystems such as coral reefs in the Hawaiian archipelago. Warming ocean temperature has increased coral disease outbreaks contributing to declines in coral cover worldwide. In this study we investigated seasonal effects of thermal stress on the prevalence of the three most widespread coral diseases in Hawai’i: Montipora white syndrome, Porites growth anomalies and Porites tissue loss syndrome. To predict outbreak likelihood we compared disease prevalence from surveys conducted between 2004 and 2015 from 18 Hawaiian Islands and atolls with biotic (e.g., coral density) and abiotic (satellite-derived sea surface temperature metrics) variables using boosted regression trees. To date, the only coral disease forecast models available were developed for Acropora white syndrome on the Great Barrier Reef (GBR). Given the complexities of disease etiology, differences in host demography and environmental conditions across reef regions, it is important to refine and adapt such models for different diseases and geographic regions of interest. Similar to the Acropora white syndrome models, anomalously warm conditions were important for predicting Montipora white syndrome, possibly due to a relationship between thermal stress and a compromised host immune system. However, coral density and winter conditions were the most important predictors of all three coral diseases in this study, enabling development of a forecasting system that can predict regions of elevated disease risk up to six months before an expected outbreak. Our research indicates satellite-derived systems for forecasting disease outbreaks can be appropriately adapted from the GBR tools and applied for a variety of diseases in a new region. These models can be used to enhance management capacity to prepare for and respond to emerging coral diseases throughout Hawai’i and can be

78 FR 12702 - Endangered and Threatened Species; Proposed Rule To List 66 Reef-Building Coral Species; Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-25

... Endangered Species Act (ESA); Extension of Public Comment Period and Notice of Public Hearing AGENCY... RIN 0648-XT12 Endangered and Threatened Species; Proposed Rule To List 66 Reef- Building Coral Species... species as threatened or endangered under the ESA. We concluded that 12 of the petitioned coral species...

[Growth characteristics of Porites lutea skeleton in east sea area of Hainan Island, China and main affecting environmental factors.

PubMed

Jiang, Qiao Wen; Cao, Zhi Min; Wang, Dao Ru; Li, Yuan Chao; Ni, Jian Yu

2016-03-01

The growth characteristics of Porites lutea skeleton in east sea area of Hainan Island were studied by CoralXDS software based on X-ray chronology. The growth parameters obtained included extension rate (ER), skeleton density (D), and calcification rate (CR). The results showed that ER varied from 0.49 to 1.10 cm·a -1 with an annual average of 0.76 cm·a -1 , D varied from 1.11 to 1.35 g·cm -3 with an annual average of 1.22 g·cm -3 , and CR varied from 0.55 to 1.41 g·cm -2 ·a -1 with an annual average of 0.94 g·cm -2 ·a -1 . Statistical analyses indicated that sea surface temperature (SST) was the key environmental factor that controlled the growth characteristics, as it highly co-varied with ER and CR, less so with D. All of the three growth characteristics increased with the increase of SST. There were other factors that influenced the growth characteristics of the coral column, such as light, water salinity, and hydrodynamics, etc. In addition, typhoon and severe tropical storms also imposed a significant impact on the growth pattern of Porites lutea coral. The change in growth pattern of coral skeleton in east of Hainan Island was a response to complex climate fluctuation. Over the past century, SST of east Hainan Island dramatically increased at a rate of 0.15 ℃·(10 a) -1 . The SST increase trend for the oceanic region could be divided into two stages, early 1940s and early 1980s. The human activities and global warming was the main causes for the increase of SST.

Ocean acidification causes bleaching and productivity loss in coral reef builders

PubMed Central

Anthony, K. R. N.; Kline, D. I.; Diaz-Pulido, G.; Dove, S.; Hoegh-Guldberg, O.

2008-01-01

Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders. In addition, acidification is likely to affect the relationship between corals and their symbiotic dinoflagellates and the productivity of this association. However, little is known about how acidification impacts on the physiology of reef builders and how acidification interacts with warming. Here, we report on an 8-week study that compared bleaching, productivity, and calcification responses of crustose coralline algae (CCA) and branching (Acropora) and massive (Porites) coral species in response to acidification and warming. Using a 30-tank experimental system, we manipulated CO2 levels to simulate doubling and three- to fourfold increases [Intergovernmental Panel on Climate Change (IPCC) projection categories IV and VI] relative to present-day levels under cool and warm scenarios. Results indicated that high CO2 is a bleaching agent for corals and CCA under high irradiance, acting synergistically with warming to lower thermal bleaching thresholds. We propose that CO2 induces bleaching via its impact on photoprotective mechanisms of the photosystems. Overall, acidification impacted more strongly on bleaching and productivity than on calcification. Interestingly, the intermediate, warm CO2 scenario led to a 30% increase in productivity in Acropora, whereas high CO2 lead to zero productivity in both corals. CCA were most sensitive to acidification, with high CO2 leading to negative productivity and high rates of net dissolution. Our findings suggest that sensitive reef-building species such as CCA may be pushed beyond their thresholds for growth and survival within the next few decades whereas corals will show delayed and mixed responses. PMID:18988740

Ocean acidification causes bleaching and productivity loss in coral reef builders.

PubMed

Anthony, K R N; Kline, D I; Diaz-Pulido, G; Dove, S; Hoegh-Guldberg, O

2008-11-11

Ocean acidification represents a key threat to coral reefs by reducing the calcification rate of framework builders. In addition, acidification is likely to affect the relationship between corals and their symbiotic dinoflagellates and the productivity of this association. However, little is known about how acidification impacts on the physiology of reef builders and how acidification interacts with warming. Here, we report on an 8-week study that compared bleaching, productivity, and calcification responses of crustose coralline algae (CCA) and branching (Acropora) and massive (Porites) coral species in response to acidification and warming. Using a 30-tank experimental system, we manipulated CO(2) levels to simulate doubling and three- to fourfold increases [Intergovernmental Panel on Climate Change (IPCC) projection categories IV and VI] relative to present-day levels under cool and warm scenarios. Results indicated that high CO(2) is a bleaching agent for corals and CCA under high irradiance, acting synergistically with warming to lower thermal bleaching thresholds. We propose that CO(2) induces bleaching via its impact on photoprotective mechanisms of the photosystems. Overall, acidification impacted more strongly on bleaching and productivity than on calcification. Interestingly, the intermediate, warm CO(2) scenario led to a 30% increase in productivity in Acropora, whereas high CO(2) lead to zero productivity in both corals. CCA were most sensitive to acidification, with high CO(2) leading to negative productivity and high rates of net dissolution. Our findings suggest that sensitive reef-building species such as CCA may be pushed beyond their thresholds for growth and survival within the next few decades whereas corals will show delayed and mixed responses.

The implications of reduced metabolic rate in resource-limited corals.

PubMed

Jacobson, Lianne M; Edmunds, Peter J; Muller, Erik B; Nisbet, Roger M

2016-03-01

Many organisms exhibit depressed metabolism when resources are limited, a change that makes it possible to balance an energy budget. For symbiotic reef corals, daily cycles of light and periods of intense cloud cover can be chronic causes of food limitation through reduced photosynthesis. Furthermore, coral bleaching is common in present-day reefs, creating a context in which metabolic depression could have beneficial value to corals. In the present study, corals (massive Porites spp.) were exposed to an extreme case of resource limitation by starving them of food and light for 20 days. When resources were limited, the corals depressed area-normalized respiration to 37% of initial rates, and coral biomass declined to 64% of initial amounts, yet the corals continued to produce skeletal mass. However, the declines in biomass cannot account for the declines in area-normalized respiration, as mass-specific respiration declined to 30% of the first recorded time point. Thus, these corals appear to be capable of metabolic depression. It is possible that some coral species are better able to depress metabolic rates than others; such variation could explain differential survival during conditions that limit resources (e.g. shading). Furthermore, we found that maintenance of existing biomass, in part, supports the production of skeletal mass. This association could be explained if maintenance supplies needed energy (e.g. ATP) or inorganic carbon (i.e. CO2) that otherwise limits the production of skeletal mass. Finally, the observed metabolic depression can be explained as a change in pool sizes, and does not require a change in metabolic rules. © 2016. Published by The Company of Biologists Ltd.

Development of Tissue to Total Mass Correction Factor for Porites divaricata in Calcification Rate Studies

NASA Astrophysics Data System (ADS)

Cannone, T. C.; Kelly, S. K.; Foster, K.

2013-05-01

One anticipated result of ocean acidification is lower calcification rates of corals. Many studies currently use the buoyant weights of coral nubbins as a means of estimating skeletal weight during non-destructive experiments. The objectives of this study, conducted at the Little Cayman Research Centre, were twofold: (1) to determine whether the purple and yellow color variations of Porites divaricata had similar tissue mass to total mass ratios; and (2) to determine a correction factor for tissue mass based on the total coral mass. T-test comparisons indicated that the tissue to total mass ratios were statistically similar for purple and yellow cohorts, thus allowing them to be grouped together within a given sample population. Linear regression analysis provided a correction factor (r2 = 0.69) to estimate the tissue mass from the total mass, which may eliminate the need to remove tissue during studies and allow subsequent testing on the same nubbins or their return to the natural environment. Additional work is needed in the development of a correction factor for P. divaricata with a higher prediction accuracy.

[Effect of herbivorous and corallivorous fishes on the survival of transplanted corals in the Colombian Caribbean].

PubMed

Chasqui-Velasco, Luis; Alvarado Ch, Elvira; Acero, Arturo; Zapata, Fernando A

2007-01-01

To examine the effects of herbivorous and corallivorous fishes on the survival of transplanted colonies of Montastraea annularis, Diploria labyrinthiformis and Porites astreoides, both transplanted and native colonies were full-cage enclosed and compared to open (uncaged) colonies, while caging effects were assessed with a partial-cage (roof treatment). To evaluate if transplant stress increased the corals availability to fish predation, comparisons of fish foraging intensity among transplanted versus native colonies were made. To determine the density of herbivorous and corallivorous fishes on the transplants area visual censuses were made. The transient herbivorous fishes (Scaridae and Acanthuridae) were the most abundant fishes, and the corallivorous fishes (mainly Chaetodontidae) were the scarcest. A negative effect of territorial herbivorous fishes on M annularis transplants survival was observed, mainly early on the study. Fish foraging intensity was similar on transplanted and native colonies, but differed among coral species, being lowest on D. labyrinthiformis. Fast macroalgal growth inside full-cages due to reduced fish grazing was observed. This caused partial bleaching and partial mortality in some colonies, mainly of P. astreoides. No significant difference in healthy tissue percentages among full-cage and uncaged colonies on M. annularis and D. labyrinthiformis was found, while in P. astreoides there were evilent differences. The results indicate a damselfish negative effect on transplants survival early on the study, which can change depending on the fish and coral species involved. Results also indicate a fish grazing positive effect, caused by the reduction of coral-algae competition pressure, mainly on P. astreoides. Parrotfishes seem to affect corals survival both negatively through direct biting, and positively by controlling algal growth. Overall, coral transplant success was almost unaffected by fish foraging activity although several

Ten years of change to coral communities off Mona and Desecheo Islands, Puerto Rico, from disease and bleaching.

PubMed

Bruckner, Andrew W; Hill, Ronald L

2009-11-16

Remote reefs off southwest Puerto Rico have experienced recent losses in live coral cover of 30 to 80%, primarily due to the decline of Montastraea annularis and M. faveolata from disease and bleaching. These species were formerly the largest, oldest, and most abundant corals on these reefs, constituting over 65% of the living coral cover and 40 to 80% of the total number of colonies. From 1998 to 2001, outbreaks of yellow band disease (YBD) and white plague (WP) affected 30 to 60% of the M. annularis (complex) colonies. Disease prevalence declined beginning in 2002, and then increased immediately following the 2005 mass bleaching event. Colonies of M. annularis (complex) have been reduced in abundance by 24 to 32%, and remaining colonies are missing more than half their tissue. Both M. annularis and M. faveolata have failed to recruit, resheeting has been minimal, and exposed skeletal surfaces are being colonized by macroalgae, bioeroding sponges, and hydrozoans. Other scleractinian corals were smaller in size (mean = 28 cm diameter) and exhibited lower levels of partial mortality; these taxa were affected to a lesser extent by coral diseases and bleaching-associated tissue loss over the last decade. The numbers of small colonies (1 to 9 cm) of these species identified since 2005 also exceeded numbers of larger colonies that died. These reefs appear to be exhibiting shifts in species assemblages, with replacement of M. annularis (complex) by shorter-lived brooding species and other massive and plating corals (Agaricia, Porites, Meandrina, Eusmilia, Diploria, and Siderastrea spp.). To avoid a catastrophic and permanent loss of the dominant, slow-growing reef-building corals, the causes and effects of diseases need to be better understood, and possible control mechanisms must be developed. In particular, steps must be taken to mitigate environmental and anthropogenic stressors that increase the spread and severity of disease.

Can heterotrophic uptake of dissolved organic carbon and zooplankton mitigate carbon budget deficits in annually bleached corals?

NASA Astrophysics Data System (ADS)

Levas, Stephen; Grottoli, Andréa G.; Schoepf, Verena; Aschaffenburg, Matthew; Baumann, Justin; Bauer, James E.; Warner, Mark E.

2016-06-01

Annual coral bleaching events due to increasing sea surface temperatures are predicted to occur globally by the mid-century and as early as 2025 in the Caribbean, and severely impact coral reefs. We hypothesize that heterotrophic carbon (C) in the form of zooplankton and dissolved organic carbon (DOC) is a significant source of C to bleached corals. Thus, the ability to utilize multiple pools of fixed carbon and/or increase the amount of fixed carbon acquired from one or more pools of fixed carbon (defined here as heterotrophic plasticity) could underlie coral acclimatization and persistence under future ocean-warming scenarios. Here, three species of Caribbean coral— Porites divaricata, P. astreoides, and Orbicella faveolata—were experimentally bleached for 2.5 weeks in two successive years and allowed to recover in the field. Zooplankton feeding was assessed after single and repeat bleaching, while DOC fluxes and the contribution of DOC to the total C budget were determined after single bleaching, 11 months on the reef, and repeat bleaching. Zooplankton was a large C source for P. astreoides, but only following single bleaching. DOC was a source of C for single-bleached corals and accounted for 11-36 % of daily metabolic demand (CHARDOC), but represented a net loss of C in repeat-bleached corals. In repeat-bleached corals, DOC loss exacerbated the negative C budgets in all three species. Thus, the capacity for heterotrophic plasticity in corals is compromised under annual bleaching, and heterotrophic uptake of DOC and zooplankton does not mitigate C budget deficits in annually bleached corals. Overall, these findings suggest that some Caribbean corals may be more susceptible to repeat bleaching than to single bleaching due to a lack of heterotrophic plasticity, and coral persistence under increasing bleaching frequency may ultimately depend on other factors such as energy reserves and symbiont shuffling.

Abundance, composition and growth rate of coral recruits on dead corals following the 2010 bleaching event at Mu Ko Surin, the Andaman Sea

NASA Astrophysics Data System (ADS)

Yucharoen, Mathinee; Yeemin, Thamasak; Casareto, Beatriz E.; Suzuki, Yoshimi; Samsuvan, Watchara; Sangmanee, Kanwara; Klinthong, Wanlaya; Pengsakun, Sittiporn; Sutthacheep, Makamas

2015-06-01

Elevated seawater temperatures in the summer months of 2010 were associated with widespread coral mortality in Thailand. A large number of corals at Mu Ko Surin died following the bleaching event. Understanding of the recruitment of corals would improve our ability to predict the potential for coral recovery from the impacts of bleaching events, as well as the interpretation of spatio-temporal variability in coral community structure. This study aims to examine the composition, abundance and growth rate of juvenile corals and the potential of reef recovery at Mu Ko Surin in order to help to understand how reefs react to major disturbances. We found that the densities of coral recruits varied among years and study sites. In the year 2011, coral recruitments ranged between 0.18 ± 0.02 to 1.67 ± 0.07 recruits per m2 for 10 study sites. While in 2012, the monitoring revealed a range between 0.96 ± 0.16 and 2.19 ± 0.21 recruits per m2 from 5 study sites. Fungia, Acropora, Porites and Favites were the dominant groups of coral recruits. In terms substrate forms, they were significant differences between sampling years but the preferential dominant substrate forms did not differ. The Acropora recruits at Ko Torinla showed normal distributions of size class during the two periods. Their ranges in 2011 and 2012 were 4-30 and 13-54 mm, respectively. Six species of Acropora recruits, i.e. Acropora intermedia, A. nasuta, A. cerealis, A. subulata, A. muricata and A. latistella were found. They showed diverse growth rates due to the spatial distribution of 2.11 ± 0.59 to 7.47 ± 1.37 cm per year. This study provides useful data in terms of coral recruitment and recovery from degradation and disturbance, especially from temperature changes induced by coral bleaching. The findings suggest that there is the possibility for coral recovery around Mu Ko Surin following the 2010 bleaching event.

Sedimentologic succession of uplifted coral community, Urvina Bay, Isabela Island, Galapagos Archipelago, Ecuador

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colgan, M.W.; Hollander, D.

1987-05-01

In March 1954, along the west-central coast of Isabela Island, an upward movement of magma suddenly raised Urvina Bay over 6 m and exposed several square kilometers of carbonate deposits covering a young aa lava flow (around 1000 years old). Results from 6 transect lines across the uplift, 30 cores, and 10 trenches describe the sedimentologic and ecologic transition from barren basalt to diverse carbonate sediments with small coral reefs. Along horizontal transects spanning from 0 to 7 m paleowater depth, there is a seaward progression from beaches, mangroves, and basalt to thick deposits (> 1.6 m) of carbonate sandsmore » and small coral reefs. Variation in water depth, degree of wave exposure, and irregularity of the aa lava topography provided many microhabitats where coral, calcareous algae, and mollusks settled and grew. Eight hermatypic coral species are found throughout the shelf, and three species (i.e., Pavona clavus, Pocillopora damicornis, and Porites lobata) produced five small, isolated, monospecific, coral-reef frameworks. The vertical section seen in cores and trenches shows that calcium carbonate increased upward, whereas volcanic sediments decreased; however, episodic layers occur with high concentrations of basaltic sands. In vertical samples from the central portion of the shelf, the coral population changed from small, isolated colonies of Psammocora (Plesioseris) superficalis near the basalt basement to large reef-forming colonies of Pocillopora damicornis farther upsection. Reefs of the Galapagos Islands are small and less diverse than most Pacific reefs. Nonetheless, understanding their temporal successional development should throw light on the origin and history of larger oceanic reefs in the Pacific.« less

Molybdenum isotope fractionation in scleractinian corals and its implications on biological activities

NASA Astrophysics Data System (ADS)

Wei, G.; Wang, Z.; Li, J.; Deng, W.; Chen, X.; Ma, J.; Zeng, T.

2017-12-01

Molybdenum can actively involve in many biological processes on coral reefs, and its isotope fractionation in coral skeleton is possibly linked to some biological activities. We have performed a 3-days' time-series observation in a time interval of 4 hours on both Mo concentrations and δ98/85Mo of the seawater of the Luhuitou Reef in Sanya of Southern Hainan Islands in the northern South China Sea. Both Mo concentrations and δ98/85Mo show in pace diurnal variations with temperature, pH, dissolved oxygen (DO) contents, dissolved inorganic carbon (DIC) contents and its δ13C. High Mo concentrations and low δ98/85Mo generally occur during day time, and low Mo concentrations and high δ98/85Mo occur at night, suggesting that respiration of coral dominated at night tends to uptake more Mo from seawater. A further analysis on the Mo isotopic compositions of 6 different coral species on the Luhuitou Reef indicates that different coral species has different δ98/85Mo values in their skeleton. The lowest δ98/85Mo value occurs in Fungia of 0.34 ‰, and the highest occurs in Acropora sp of 1.91 ‰. These are all lower than that of the seawater, 2.04 ‰, suggesting a specie-depended Mo fractionation on coral skeleton. Meanwhile, we measured a 32-year time series of both Mo concentrations and δ98/85Mo of a Porites coral from the Great Barrier Reefs of Australia in annual resolution. The Mo concentrations vary from 12.5 to 78.0 ng/g, with an average of 21.4 ± 0.02 ng/g, and the δ98/95Mo values change from 0.46 to 1.83‰, with an average of 1.34 ± 0.09‰. A significant negative correlation occurs between the δ98/95Mo and the Mo concentration, and a positive correlation occurs between the δ98/95Mo and the seawater surface temperature. All these suggest that Mo isotope fractionation in coral skeleton is associated with biological activities of coral, such as respiration, and the δ98/95Mo values may be used to indicate changes in the related biological activities.

Coral 13C/12C records of vertical seafloor displacement during megathrust earthquakes west of Sumatra

NASA Astrophysics Data System (ADS)

Gagan, Michael K.; Sosdian, Sindia M.; Scott-Gagan, Heather; Sieh, Kerry; Hantoro, Wahyoe S.; Natawidjaja, Danny H.; Briggs, Richard W.; Suwargadi, Bambang W.; Rifai, Hamdi

2015-12-01

The recent surge of megathrust earthquakes and tsunami disasters has highlighted the need for a comprehensive understanding of earthquake cycles along convergent plate boundaries. Space geodesy has been used to document recent crustal deformation patterns with unprecedented precision, however the production of long paleogeodetic records of vertical seafloor motion is still a major challenge. Here we show that carbon isotope ratios (δ13C) in the skeletons of massive Porites corals from west Sumatra record abrupt changes in light exposure resulting from coseismic seafloor displacements. Validation of the method is based on the coral δ13C response to uplift (and subsidence) produced by the March 2005 Mw 8.6 Nias-Simeulue earthquake, and uplift further south around Sipora Island during a M ∼ 8.4 megathrust earthquake in February 1797. At Nias, the average step-change in coral δ13C was 0.6 ± 0.1 ‰ /m for coseismic displacements of +1.8 m and -0.4 m in 2005. At Sipora, a distinct change in Porites microatoll growth morphology marks coseismic uplift of 0.7 m in 1797. In this shallow water setting, with a steep light attenuation gradient, the step-change in microatoll δ13C is 2.3 ‰ /m, nearly four times greater than for the Nias Porites. Considering the natural variability in coral skeletal δ13C, we show that the lower detection limit of the method is around 0.2 m of vertical seafloor motion. Analysis of vertical displacement for well-documented earthquakes suggests this sensitivity equates to shallow events exceeding Mw ∼ 7.2 in central megathrust and back-arc thrust fault settings. Our findings indicate that the coral 13C /12C paleogeodesy technique could be applied to convergent tectonic margins throughout the tropical western Pacific and eastern Indian oceans, which host prolific coral reefs, and some of the world's greatest earthquake catastrophes. While our focus here is the link between coral δ13C, light exposure and coseismic crustal deformation, the

Coral 13C/12C records of vertical seafloor displacement during megathrust earthquakes west of Sumatra

USGS Publications Warehouse

Gagan, Michael K.; Sosdian, Sindia M.; Scott-Gagan, Heather; Sieh, Kerry; Hantoro, Wahyoe S.; Natawidjaja, Danny H.; Briggs, Richard W.; Suwargadi, Bambang W.; Rifai, Hamdi

2015-01-01

The recent surge of megathrust earthquakes and tsunami disasters has highlighted the need for a comprehensive understanding of earthquake cycles along convergent plate boundaries. Space geodesy has been used to document recent crustal deformation patterns with unprecedented precision, however the production of long paleogeodetic records of vertical seafloor motion is still a major challenge. Here we show that carbon isotope ratios () in the skeletons of massive Porites   corals from west Sumatra record abrupt changes in light exposure resulting from coseismic seafloor displacements. Validation of the method is based on the coral  response to uplift (and subsidence) produced by the March 2005 Mw 8.6 Nias–Simeulue earthquake, and uplift further south around Sipora Island during a M∼8.4 megathrust earthquake in February 1797. At Nias, the average step-change in coral  was 0.6±0.1‰/m for coseismic displacements of +1.8 m and −0.4 m in 2005. At Sipora, a distinct change in Porites  microatoll growth morphology marks coseismic uplift of 0.7 m in 1797. In this shallow water setting, with a steep light attenuation gradient, the step-change in microatoll  is2.3‰/m, nearly four times greater than for the Nias Porites  . Considering the natural variability in coral skeletal , we show that the lower detection limit of the method is around 0.2 m of vertical seafloor motion. Analysis of vertical displacement for well-documented earthquakes suggests this sensitivity equates to shallow events exceedingMw∼7.2 in central megathrust and back-arc thrust fault settings. Our findings indicate that the coral  paleogeodesy technique could be applied to convergent tectonic margins throughout the tropical western Pacific and eastern Indian oceans, which host prolific coral reefs, and some of the world's greatest earthquake catastrophes. While our focus here is the link between coral , light exposure and coseismic crustal deformation, the same principles

Deep reefs are not universal refuges: Reseeding potential varies among coral species

PubMed Central

Bongaerts, Pim; Riginos, Cynthia; Brunner, Ramona; Englebert, Norbert; Smith, Struan R.; Hoegh-Guldberg, Ove

2017-01-01

Deep coral reefs (that is, mesophotic coral ecosystems) can act as refuges against major disturbances affecting shallow reefs. It has been proposed that, through the provision of coral propagules, such deep refuges may aid in shallow reef recovery; however, this “reseeding” hypothesis remains largely untested. We conducted a genome-wide assessment of two scleractinian coral species with contrasting reproductive modes, to assess the potential for connectivity between mesophotic (40 m) and shallow (12 m) depths on an isolated reef system in the Western Atlantic (Bermuda). To overcome the pervasive issue of endosymbiont contamination associated with de novo sequencing of corals, we used a novel subtraction reference approach. We have demonstrated that strong depth-associated selection has led to genome-wide divergence in the brooding species Agaricia fragilis (with divergence by depth exceeding divergence by location). Despite introgression from shallow into deep populations, a lack of first-generation migrants indicates that effective connectivity over ecological time scales is extremely limited for this species and thus precludes reseeding of shallow reefs from deep refuges. In contrast, no genetic structuring between depths (or locations) was observed for the broadcasting species Stephanocoenia intersepta, indicating substantial potential for vertical connectivity. Our findings demonstrate that vertical connectivity within the same reef system can differ greatly between species and that the reseeding potential of deep reefs in Bermuda may apply to only a small number of scleractinian species. Overall, we argue that the “deep reef refuge hypothesis” holds for individual coral species during episodic disturbances but should not be assumed as a broader ecosystem-wide phenomenon. PMID:28246645

Reef flattening effects on total richness and species responses in the Caribbean.

PubMed

Newman, Steven P; Meesters, Erik H; Dryden, Charlie S; Williams, Stacey M; Sanchez, Cristina; Mumby, Peter J; Polunin, Nicholas V C

2015-11-01

There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and community composition, but little is known about its role for other taxa or species-specific responses. This study reveals the importance of reef habitat complexity and structural components to different taxa of macrofauna, total species richness, and individual coral and fish species in the Caribbean. Species presence and richness of different taxa were visually quantified in one hundred 25-m(2) plots in three marine reserves in the Caribbean. Sampling was evenly distributed across five levels of visually estimated reef complexity, with five structural components also recorded: the number of corals, number of large corals, slope angle, maximum sponge and maximum octocoral height. Taking advantage of natural heterogeneity in structural complexity within a particular coral reef habitat (Orbicella reefs) and discrete environmental envelope, thus minimizing other sources of variability, the relative importance of reef complexity and structural components was quantified for different taxa and individual fish and coral species on Caribbean coral reefs using boosted regression trees (BRTs). Boosted regression tree models performed very well when explaining variability in total (82·3%), coral (80·6%) and fish species richness (77·3%), for which the greatest declines in richness occurred below intermediate reef complexity levels. Complexity accounted for very little of the variability in octocorals, sponges, arthropods, annelids or anemones. BRTs revealed species-specific variability and importance for reef complexity and structural components. Coral and fish species occupancy generally declined at low complexity levels, with the exception of two coral species (Pseudodiploria strigosa and Porites divaricata) and four fish species (Halichoeres bivittatus, H

Copper (Cu) content in Porites lutea at South Java Sea: Case study at Pantai Kondang Merak, Malang, Indonesia

NASA Astrophysics Data System (ADS)

Luthfi, Oktiyas Muzaky; Rijatmoko, Sigit; Isdianto, Andik; Setyohadi, Daduk; Jauhari, Alfan; Lubis, Ali Arman

2017-11-01

The reef flat area in Pantai Kondang Merak is similar to others that are influenced by the high and low tide. Coral in this area should deal with high water temperature during low tide and should withstand exposure to air. These conditions lead to coral stress. Another stressor is heavy metals such copper. Annual band in Porites lutea can be a bioindicator to investigate the heavy metal contaminations as resulted from the human and natural activity. To measure heavy metal copper in the coral skeleton, we used ICP-OES (iCAP 7400 Series). Heavy metal was absorbed by coral tissue and is bind in their aragonite. This research showed 7 years of the heavy metal sample in coral banding were 9.3; 9.223; 10.09; 10.67; 8.7 and 10.37 mg/Kg (KM1). While in sample 2 (KM2) the concentration of copper was 12.98; 12.5; 15.023; 15.27; 19.811; 28.229 mg/kg. The average of heavy metal KM2 (19.157 mg/kg) is higher than KM1 (0.765 mg/kg). From these data, we can know the amount of heavy metal in South Java Sea from the past or sclerochronology.

Status of coral reef species at Chabahar Bay, Sistan and Baluchistan, Iran.

PubMed

Teymour, Rad A; Sanjani, M S

2010-04-15

This study was carried out in the coral growing zone at Chabahar Bay where it located at 25 degrees 17' N and 60 degrees 36'E. It is called horseshoe Bay, because of its semicircle shape. Some destroyer factors have been affected on the health of coral reefs in Chabahar Bay. Port constructions, dredging operations, spearfishing, anchorages and scuba diving activities were distinguished as the most important problems of coral reef in Chabahar Bay. This study was conducted in order to access Semi-Qualitative Indexes of corals in different areas of Chabahar Bay. Five stations were chosen in east and north part of the Bay, where the most construction activities happened. Rectangular Transect and CoralWatch Racket were used to determine the status of the corals. During study, two classes of Hexacoralia and Octocoralia with 15 families were recorded. Twenty one species of hard coral and 10 species of soft coral were recorded. Hexacoralia was recorded the higher number of family with 10 families and 21 species and Octocoralia was recorded the lower with 5 families and 10 species. Hard corals were dominant. The ranges of qualitative indexes showed, of five stations, three of them (stations 2, 4, 5) showed Good Development and two stations (stations 1, 3) showed Fair Development. For the Condition Index, two stations showed Good Condition (stations 1, 5) and two stations showed Fair Condition (stations 2, 3). Only station 4 showed Poor Condition. The ranges of the Succession Index Showed, four stations (stations 1, 2, 3, 4) were in Very poor Succession and one station (stations 5) showed Poor Succession.

The microbiome of coral surface mucus has a key role in mediating holobiont health and survival upon disturbance.

PubMed

Glasl, Bettina; Herndl, Gerhard J; Frade, Pedro R

2016-09-01

Microbes are well-recognized members of the coral holobiont. However, little is known about the short-term dynamics of mucus-associated microbial communities under natural conditions and after disturbances, and how these dynamics relate to the host's health. Here we examined the natural variability of prokaryotic communities (based on 16S ribosomal RNA gene amplicon sequencing) associating with the surface mucus layer (SML) of Porites astreoides, a species exhibiting cyclical mucus aging and shedding. Shifts in the prokaryotic community composition during mucus aging led to the prevalence of opportunistic and potentially pathogenic bacteria (Verrucomicrobiaceae and Vibrionaceae) in aged mucus and to a twofold increase in prokaryotic abundance. After the release of aged mucus sheets, the community reverted to its original state, dominated by Endozoicimonaceae and Oxalobacteraceae. Furthermore, we followed the fate of the coral holobiont upon depletion of its natural mucus microbiome through antibiotics treatment. After re-introduction to the reef, healthy-looking microbe-depleted corals started exhibiting clear signs of bleaching and necrosis. Recovery versus mortality of the P. astreoides holobiont was related to the degree of change in abundance distribution of the mucus microbiome. We conclude that the natural prokaryotic community inhabiting the coral SML contributes to coral health and that cyclical mucus shedding has a key role in coral microbiome dynamics.

Bleaching response of coral species in the context of assemblage response

NASA Astrophysics Data System (ADS)

Swain, Timothy D.; DuBois, Emily; Goldberg, Scott J.; Backman, Vadim; Marcelino, Luisa A.

2017-06-01

Caribbean coral reefs are declining due to a mosaic of local and global stresses, including climate change-induced thermal stress. Species and assemblage responses differ due to factors that are not easily identifiable or quantifiable. We calculated a novel species-specific metric of coral bleaching response, taxon- α and - β, which relates the response of a species to that of its assemblages for 16 species over 18 assemblages. By contextualizing species responses within the response of their assemblages, the effects of environmental factors are removed and intrinsic differences among taxa are revealed. Most corals experience either a saturation response, overly sensitive to weak stress ( α > 0) but under-responsive compared to assemblage bleaching ( β < 1), or a threshold response, insensitive to weak stress ( α < 0) but over-responsive compared to assemblage bleaching ( β > 1). This metric may help reveal key factors of bleaching susceptibility and identify species as targets for conservation.

Bleaching response of coral species in the context of assemblage response.

PubMed

Swain, Timothy D; DuBois, Emily; Goldberg, Scott J; Backman, Vadim; Marcelino, Luisa A

2017-06-01

Caribbean coral reefs are declining due to a mosaic of local and global stresses, including climate change-induced thermal stress. Species and assemblage responses differ due to factors that are not easily identifiable or quantifiable. We calculated a novel species-specific metric of coral bleaching response, taxon-α and -β, which relates the response of a species to that of its assemblages for 16 species over 18 assemblages. By contextualizing species responses within the response of their assemblages, the effects of environmental factors are removed and intrinsic differences among taxa are revealed. Most corals experience either a saturation response, overly-sensitive to weak stress (α > 0) but under-responsive compared to assemblage bleaching (β < 1), or a threshold response, insensitive to weak stress (α < 0) but over-responsive compared to assemblage bleaching (β > 1). This metric may help reveal key factors of bleaching susceptibility and identify species as targets for conservation.

77 FR 22749 - Petition To List 83 Species of Coral as Threatened or Endangered Under the Endangered Species Act...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-17

... threatened or endangered under the Endangered Species Act (ESA) and to notify the public about future public... Candidate Coral Species Petitioned Under the U.S. Endangered Species Act (Status Review Report) and the draft Management Report for 82 Corals Status Review under the Endangered Species Act: Assessment of...

Recurrent disturbances, recovery trajectories, and resilience of coral assemblages on a South Central Pacific reef

NASA Astrophysics Data System (ADS)

Adjeroud, M.; Michonneau, F.; Edmunds, P. J.; Chancerelle, Y.; de Loma, T. Lison; Penin, L.; Thibaut, L.; Vidal-Dupiol, J.; Salvat, B.; Galzin, R.

2009-09-01

Coral reefs are increasingly threatened by various disturbances, and a critical challenge is to determine their ability for resistance and resilience. Coral assemblages in Moorea, French Polynesia, have been impacted by multiple disturbances (one cyclone and four bleaching events between 1991 and 2006). The 1991 disturbances caused large declines in coral cover (~51% to ~22%), and subsequent colonization by turf algae (~16% to ~49%), but this phase-shift from coral to algal dominance has not persisted. Instead, the composition of the coral community changed following the disturbances, notably favoring an increased cover of Porites, reduced cover of Montipora and Pocillopora, and a full return of Acropora; in this form, the reef returned to pre-disturbance coral cover within a decade. Thus, this coral assemblage is characterized by resilience in terms of coral cover, but plasticity in terms of community composition.

High resolution windows into early Holocene climate: Sr/(Ca) coral records from the Huon Peninsula

NASA Astrophysics Data System (ADS)

McCulloch, Malcolm; Mortimer, Graham; Esat, Tezer; Xianhua, Li; Pillans, Brad; Chappell, John

1996-02-01

High-precision measurements of Sr/Ca ratios are reported for Porites corals from the uplifted Holocene coral terraces at Huon Peninsula, Papua New Guinea. The early Holocene Porites have UTh mass spectrometric ages of 8920 ± 60 yr and 7370 ± 50 yr, and δ 234U(t) values of 145 ± 2, similar to modern seawater. The Sr/Ca coral records provide 5-6 year high resolution (near weekly) time windows into early Holocene sea surface temperatures. Seasonal temperature fluctuations are generally in the range of ± 1°C, with occasional excursions of ± 2°C, which may indicate the more frequent recurrence of very strong ENSO (El Niño-Southern Oscillation) events. Mean annual Sr/Ca temperatures of 24.2 ± 1.1°C and 22.9 ± 0.8°C have been obtained, which are ˜ 2-3°C cooler than that exhibited by a modern Porites. These results indicate that, during the early Holocene, the equatorial western Pacific ocean was at least several degrees cooler than present-day temperatures. This is consistent with late glacial coral records from the Caribbean that indicate lower (˜ 6°C) sea surface temperatures for the equatorial oceans. The Huon Peninsula corals also indicate that SSTs were several degrees cooler than those in the Caribbean during the early Holocene. Thus, although the northern hemisphere summer radiation maximum occurred at ˜ 10 ka, there appears to have been a significant lag in the response of the equatorial western Pacific ocean to this warming. Cooler early Holocene sea surface temperatures in the western Pacific may have been due to changing patterns of ocean-atmosphere circulation, resulting from the exposure of large areas of continental shelf in the southeast Asia region, a consequence of lower glacial sea levels. It is likely that ocean temperatures in the Huon Peninsula were influenced by the opening at ˜ 7 ka of the Torres Strait, that now separates New Guinea from the Australian mainland.

The Coral Trait Database, a curated database of trait information for coral species from the global oceans

NASA Astrophysics Data System (ADS)

Madin, Joshua S.; Anderson, Kristen D.; Andreasen, Magnus Heide; Bridge, Tom C. L.; Cairns, Stephen D.; Connolly, Sean R.; Darling, Emily S.; Diaz, Marcela; Falster, Daniel S.; Franklin, Erik C.; Gates, Ruth D.; Hoogenboom, Mia O.; Huang, Danwei; Keith, Sally A.; Kosnik, Matthew A.; Kuo, Chao-Yang; Lough, Janice M.; Lovelock, Catherine E.; Luiz, Osmar; Martinelli, Julieta; Mizerek, Toni; Pandolfi, John M.; Pochon, Xavier; Pratchett, Morgan S.; Putnam, Hollie M.; Roberts, T. Edward; Stat, Michael; Wallace, Carden C.; Widman, Elizabeth; Baird, Andrew H.

2016-03-01

Trait-based approaches advance ecological and evolutionary research because traits provide a strong link to an organism’s function and fitness. Trait-based research might lead to a deeper understanding of the functions of, and services provided by, ecosystems, thereby improving management, which is vital in the current era of rapid environmental change. Coral reef scientists have long collected trait data for corals; however, these are difficult to access and often under-utilized in addressing large-scale questions. We present the Coral Trait Database initiative that aims to bring together physiological, morphological, ecological, phylogenetic and biogeographic trait information into a single repository. The database houses species- and individual-level data from published field and experimental studies alongside contextual data that provide important framing for analyses. In this data descriptor, we release data for 56 traits for 1547 species, and present a collaborative platform on which other trait data are being actively federated. Our overall goal is for the Coral Trait Database to become an open-source, community-led data clearinghouse that accelerates coral reef research.

The Coral Trait Database, a curated database of trait information for coral species from the global oceans

PubMed Central

Madin, Joshua S.; Anderson, Kristen D.; Andreasen, Magnus Heide; Bridge, Tom C.L.; Cairns, Stephen D.; Connolly, Sean R.; Darling, Emily S.; Diaz, Marcela; Falster, Daniel S.; Franklin, Erik C.; Gates, Ruth D.; Hoogenboom, Mia O.; Huang, Danwei; Keith, Sally A.; Kosnik, Matthew A.; Kuo, Chao-Yang; Lough, Janice M.; Lovelock, Catherine E.; Luiz, Osmar; Martinelli, Julieta; Mizerek, Toni; Pandolfi, John M.; Pochon, Xavier; Pratchett, Morgan S.; Putnam, Hollie M.; Roberts, T. Edward; Stat, Michael; Wallace, Carden C.; Widman, Elizabeth; Baird, Andrew H.

2016-01-01

Trait-based approaches advance ecological and evolutionary research because traits provide a strong link to an organism’s function and fitness. Trait-based research might lead to a deeper understanding of the functions of, and services provided by, ecosystems, thereby improving management, which is vital in the current era of rapid environmental change. Coral reef scientists have long collected trait data for corals; however, these are difficult to access and often under-utilized in addressing large-scale questions. We present the Coral Trait Database initiative that aims to bring together physiological, morphological, ecological, phylogenetic and biogeographic trait information into a single repository. The database houses species- and individual-level data from published field and experimental studies alongside contextual data that provide important framing for analyses. In this data descriptor, we release data for 56 traits for 1547 species, and present a collaborative platform on which other trait data are being actively federated. Our overall goal is for the Coral Trait Database to become an open-source, community-led data clearinghouse that accelerates coral reef research. PMID:27023900

The Coral Trait Database, a curated database of trait information for coral species from the global oceans.

PubMed

Madin, Joshua S; Anderson, Kristen D; Andreasen, Magnus Heide; Bridge, Tom C L; Cairns, Stephen D; Connolly, Sean R; Darling, Emily S; Diaz, Marcela; Falster, Daniel S; Franklin, Erik C; Gates, Ruth D; Harmer, Aaron; Hoogenboom, Mia O; Huang, Danwei; Keith, Sally A; Kosnik, Matthew A; Kuo, Chao-Yang; Lough, Janice M; Lovelock, Catherine E; Luiz, Osmar; Martinelli, Julieta; Mizerek, Toni; Pandolfi, John M; Pochon, Xavier; Pratchett, Morgan S; Putnam, Hollie M; Roberts, T Edward; Stat, Michael; Wallace, Carden C; Widman, Elizabeth; Baird, Andrew H

2016-03-29

Trait-based approaches advance ecological and evolutionary research because traits provide a strong link to an organism's function and fitness. Trait-based research might lead to a deeper understanding of the functions of, and services provided by, ecosystems, thereby improving management, which is vital in the current era of rapid environmental change. Coral reef scientists have long collected trait data for corals; however, these are difficult to access and often under-utilized in addressing large-scale questions. We present the Coral Trait Database initiative that aims to bring together physiological, morphological, ecological, phylogenetic and biogeographic trait information into a single repository. The database houses species- and individual-level data from published field and experimental studies alongside contextual data that provide important framing for analyses. In this data descriptor, we release data for 56 traits for 1547 species, and present a collaborative platform on which other trait data are being actively federated. Our overall goal is for the Coral Trait Database to become an open-source, community-led data clearinghouse that accelerates coral reef research.

Testing the genetic predictions of a biogeographical model in a dominant endemic Eastern Pacific coral (Porites panamensis) using a genetic seascape approach

PubMed Central

Saavedra-Sotelo, Nancy C; Calderon-Aguilera, Luis E; Reyes-Bonilla, Héctor; Paz-García, David A; López-Pérez, Ramón A; Cupul-Magaña, Amilcar; Cruz-Barraza, José A; Rocha-Olivares, Axayácatl

2013-01-01

The coral fauna of the Eastern Tropical Pacific (ETP) is depauperate and peripheral; hence, it has drawn attention to the factors allowing its survival. Here, we use a genetic seascape approach and ecological niche modeling to unravel the environmental factors correlating with the genetic variation of Porites panamensis, a hermatypic coral endemic to the ETP. Specifically, we test if levels of diversity and connectivity are higher among abundant than among depauperate populations, as expected by a geographically relaxed version of the Abundant Center Hypothesis (rel-ACH). Unlike the original ACH, referring to a geographical center of distribution of maximal abundance, the rel-ACH refers only to a center of maximum abundance, irrespective of its geographic position. The patterns of relative abundance of P. panamensis in the Mexican Pacific revealed that northern populations from Baja California represent its center of abundance; and southern depauperate populations along the continental margin are peripheral relative to it. Genetic patterns of diversity and structure of nuclear DNA sequences (ribosomal DNA and a single copy open reading frame) and five alloenzymatic loci partially agreed with rel-ACH predictions. We found higher diversity levels in peninsular populations and significant differentiation between peninsular and continental colonies. In addition, continental populations showed higher levels of differentiation and lower connectivity than peninsular populations in the absence of isolation by distance in each region. Some discrepancies with model expectations may relate to the influence of significant habitat discontinuities in the face of limited dispersal potential. Environmental data analyses and niche modeling allowed us to identify temperature, water clarity, and substrate availability as the main factors correlating with patterns of abundance, genetic diversity, and structure, which may hold the key to the survival of P. panamensis in the face of

Genome-Based Analyses of Six Hexacorallian Species Reject the "Naked Coral" Hypothesis.

PubMed

Wang, Xin; Drillon, Guénola; Ryu, Taewoo; Voolstra, Christian R; Aranda, Manuel

2017-10-01

Scleractinian corals are the foundation species of the coral-reef ecosystem. Their calcium carbonate skeletons form extensive structures that are home to millions of species, making coral reefs one of the most diverse ecosystems of our planet. However, our understanding of how reef-building corals have evolved the ability to calcify and become the ecosystem builders they are today is hampered by uncertain relationships within their subclass Hexacorallia. Corallimorpharians have been proposed to originate from a complex scleractinian ancestor that lost the ability to calcify in response to increasing ocean acidification, suggesting the possibility for corals to lose and gain the ability to calcify in response to increasing ocean acidification. Here, we employed a phylogenomic approach using whole-genome data from six hexacorallian species to resolve the evolutionary relationship between reef-building corals and their noncalcifying relatives. Phylogenetic analysis based on 1,421 single-copy orthologs, as well as gene presence/absence and synteny information, converged on the same topologies, showing strong support for scleractinian monophyly and a corallimorpharian sister clade. Our broad phylogenomic approach using sequence-based and sequence-independent analyses provides unambiguous evidence for the monophyly of scleractinian corals and the rejection of corallimorpharians as descendants of a complex coral ancestor. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

A model for wave control on coral breakage and species distribution in the Hawaiian Islands

USGS Publications Warehouse

Storlazzi, C.D.; Brown, E.K.; Field, M.E.; Rodgers, K.; Jokiel, P.L.

2005-01-01

The fringing reef off southern Molokai, Hawaii, is currently being studied as part of a multi-disciplinary project led by the US Geological Survey. As part of this study, modeling and field observations were utilized to help understand the physical controls on reef morphology and the distribution of different coral species. A model was developed that calculates wave-induced hydrodynamic forces on corals of a specific form and mechanical strength. From these calculations, the wave conditions under which specific species of corals would either be stable or would break due to the imposed wave-induced forces were determined. By combining this hydrodynamic force-balance model with various wave model output for different oceanographic conditions experienced in the study area, we were able to map the locations where specific coral species should be stable (not subject to frequent breakage) in the study area. The combined model output was then compared with data on coral species distribution and coral cover at 12 sites along Molokai's south shore. Observations and modeling suggest that the transition from one coral species to another may occur when the ratio of the coral colony's mechanical strengths to the applied (wave-induced) forces may be as great as 5:1, and not less than 1:1 when corals would break. This implies that coral colony's mechanical strength and wave-induced forces may be important in defining gross coral community structure over large (orders of 10's of meters) spatial scales. ?? Springer-Verlag 2004.

Evidence for water-mediated mechanisms in coral-algal interactions.

PubMed

Jorissen, Hendrikje; Skinner, Christina; Osinga, Ronald; de Beer, Dirk; Nugues, Maggy M

2016-08-17

Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral-algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral-algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites) interfaces with thick turf algae, macroalgae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support the importance of water-mediated transport mechanisms in coral-algal interactions. Shifts towards algal dominance, particularly dense assemblages, may lead to thicker DBLs, higher hypoxia, and higher concentrations of harmful metabolites and pathogens along coral borders, which in turn may facilitate algal overgrowth of live corals. These effects may be mediated by flow speed and orientation. © 2016 The Author(s).

Sponge erosion under acidification and warming scenarios: differential impacts on living and dead coral.

PubMed

Stubler, Amber D; Furman, Bradley T; Peterson, Bradley J

2015-11-01

Ocean acidification will disproportionately impact the growth of calcifying organisms in coral reef ecosystems. Simultaneously, sponge bioerosion rates have been shown to increase as seawater pH decreases. We conducted a 20-week experiment that included a 4-week acclimation period with a high number of replicate tanks and a fully orthogonal design with two levels of temperature (ambient and +1 °C), three levels of pH (8.1, 7.8, and 7.6), and two levels of boring sponge (Cliona varians, present and absent) to account for differences in sponge attachment and carbonate change for both living and dead coral substrate (Porites furcata). Net coral calcification, net dissolution/bioerosion, coral and sponge survival, sponge attachment, and sponge symbiont health were evaluated. Additionally, we used the empirical data from the experiment to develop a stochastic simulation of carbonate change for small coral clusters (i.e., simulated reefs). Our findings suggest differential impacts of temperature, pH and sponge presence for living and dead corals. Net coral calcification (mg CaCO3  cm(-2)  day(-1) ) was significantly reduced in treatments with increased temperature (+1 °C) and when sponges were present; acidification had no significant effect on coral calcification. Net dissolution of dead coral was primarily driven by pH, regardless of sponge presence or seawater temperature. A reevaluation of the current paradigm of coral carbonate change under future acidification and warming scenarios should include ecologically relevant timescales, species interactions, and community organization to more accurately predict ecosystem-level response to future conditions. © 2015 John Wiley & Sons Ltd.

Interactive effects of three pervasive marine stressors in a post-disturbance coral reef

NASA Astrophysics Data System (ADS)

Gil, Michael A.; Goldenberg, Silvan U.; Ly Thai Bach, Anne; Mills, Suzanne C.; Claudet, Joachim

2016-12-01

Ecosystems are commonly affected by natural, episodic disturbances that can abruptly and drastically alter communities. Although it has been shown that resilient ecosystems can eventually recover to pre-disturbed states, the extent to which communities in early stages of recovery could be affected by multiple anthropogenic stressors is poorly understood. Pervasive and rising anthropogenic stressors in coastal marine systems that could interactively affect the recovery of these systems following natural disturbances include high sedimentation, nutrient enrichment, and overfishing. Using a 6-month field experiment, we examined the effects of all combinations of these three stressors on key functional groups in the benthic community growing on simulated, post-disturbance reef patches within a system recovering from large-scale natural disturbances (corallivorous seastar outbreak and cyclone). Our study revealed that sedimentation, nutrient enrichment, and overfishing (simulated using exclusion cages) interactively affected coral survival and algal growth, with taxon-specific effects at multiple scales. First, our treatments affected corals and algae differently, with sedimentation being more detrimental to macroalgal growth but less detrimental to coral ( Porites rus) survival in caged plots, driving significant interactions between sedimentation and caging for both taxa. We also observed distinct responses between coral species and between algal functional groups, with the most extensive responses from algal turf biomass, for which sedimentation suppressed the synergistic (positive) combined effect of nutrient enrichment and caging. Our findings suggest that different combinations of ubiquitous anthropogenic stressors, related to either sea- or land-based activities, interactively influence community recovery from disturbance and may alter species compositions in the resulting community. Our findings further suggest that anthropogenic stressors could promote further

Reef Fishes in Biodiversity Hotspots Are at Greatest Risk from Loss of Coral Species

PubMed Central

Holbrook, Sally J.; Schmitt, Russell J.; Messmer, Vanessa; Brooks, Andrew J.; Srinivasan, Maya; Munday, Philip L.; Jones, Geoffrey P.

2015-01-01

Coral reef ecosystems are under a variety of threats from global change and anthropogenic disturbances that are reducing the number and type of coral species on reefs. Coral reefs support upwards of one third of all marine species of fish, so the loss of coral habitat may have substantial consequences to local fish diversity. We posit that the effects of habitat degradation will be most severe in coral regions with highest biodiversity of fishes due to greater specialization by fishes for particular coral habitats. Our novel approach to this important but untested hypothesis was to conduct the same field experiment at three geographic locations across the Indo-Pacific biodiversity gradient (Papua New Guinea; Great Barrier Reef, Australia; French Polynesia). Specifically, we experimentally explored whether the response of local fish communities to identical changes in diversity of habitat-providing corals was independent of the size of the regional species pool of fishes. We found that the proportional reduction (sensitivity) in fish biodiversity to loss of coral diversity was greater for regions with larger background species pools, reflecting variation in the degree of habitat specialization of fishes across the Indo-Pacific diversity gradient. This result implies that habitat-associated fish in diversity hotspots are at greater risk of local extinction to a given loss of habitat diversity compared to regions with lower species richness. This mechanism, related to the positive relationship between habitat specialization and regional biodiversity, and the elevated extinction risk this poses for biodiversity hotspots, may apply to species in other types of ecosystems. PMID:25970588

Reef fishes in biodiversity hotspots are at greatest risk from loss of coral species.

PubMed

Holbrook, Sally J; Schmitt, Russell J; Messmer, Vanessa; Brooks, Andrew J; Srinivasan, Maya; Munday, Philip L; Jones, Geoffrey P

2015-01-01

Coral reef ecosystems are under a variety of threats from global change and anthropogenic disturbances that are reducing the number and type of coral species on reefs. Coral reefs support upwards of one third of all marine species of fish, so the loss of coral habitat may have substantial consequences to local fish diversity. We posit that the effects of habitat degradation will be most severe in coral regions with highest biodiversity of fishes due to greater specialization by fishes for particular coral habitats. Our novel approach to this important but untested hypothesis was to conduct the same field experiment at three geographic locations across the Indo-Pacific biodiversity gradient (Papua New Guinea; Great Barrier Reef, Australia; French Polynesia). Specifically, we experimentally explored whether the response of local fish communities to identical changes in diversity of habitat-providing corals was independent of the size of the regional species pool of fishes. We found that the proportional reduction (sensitivity) in fish biodiversity to loss of coral diversity was greater for regions with larger background species pools, reflecting variation in the degree of habitat specialization of fishes across the Indo-Pacific diversity gradient. This result implies that habitat-associated fish in diversity hotspots are at greater risk of local extinction to a given loss of habitat diversity compared to regions with lower species richness. This mechanism, related to the positive relationship between habitat specialization and regional biodiversity, and the elevated extinction risk this poses for biodiversity hotspots, may apply to species in other types of ecosystems.

Species-area relationships in coral communities: evaluating mechanisms for a commonly observed pattern

NASA Astrophysics Data System (ADS)

Huntington, B. E.; Lirman, D.

2012-12-01

Landscape-scale attributes of patch size, spatial isolation, and topographic complexity are known to influence diversity and abundance in terrestrial and marine systems, but remain collectively untested for reef-building corals. To investigate the relationship between the coral assemblage and seascape variation in reef habitats, we took advantage of the distinct boundaries, spatial configurations, and topographic complexities among artificial reef patches to overcome the difficulties of manipulating natural reefs. Reef size (m2) was found to be the foremost predictor of coral richness in accordance with species-area relationship predictions. Larger reefs were also found to support significantly higher colony densities, enabling us to reject the null hypothesis of random placement (a sampling artifact) in favor of target area predictions that suggest greater rates of immigration on larger reefs. Unlike the pattern previously documented for reef fishes, topographic complexity was not a significant predictor of any coral assemblage response variable, despite the range of complexity values sampled. Lastly, coral colony density was best explained by both increasing reef size and decreasing reef spatial isolation, a pattern found exclusively among brooding species with shorter larval dispersal distances. We conclude that seascape attributes of reef size and spatial configuration within the seascape can influence the species richness and abundance of the coral community at relatively small spatial scales (<1 km). Specifically, we demonstrate how patterns in the coral communities that have naturally established on these manipulated reefs agree with the target area and island biogeography mechanisms to drive species-area relationships in reef-building corals. Based on the patterns documented in artificial reefs, habitat degradation that results in smaller, more isolated natural reefs may compromise coral diversity.

Novel transcriptome resources for three scleractinian coral species from the Indo-Pacific

PubMed Central

Kenkel, Carly D.; Bay, Line K

2017-01-01

Abstract Transcriptomic resources for coral species can provide insight into coral evolutionary history and stress-response physiology. Goniopora columna, Galaxea astreata, and Galaxea acrhelia are scleractinian corals of the Indo-Pacific, representing a diversity of morphologies and life-history traits. G. columna and G. astreata are common and cosmopolitan, while G. acrhelia is largely restricted to the coral triangle and Great Barrier Reef. Reference transcriptomes for these species were assembled from replicate colony fragments exposed to elevated (31°C) and ambient (27°C) temperatures. Trinity was used to create de novo assemblies for each species from 92–102 million raw Illumina Hiseq 2 × 150 bp reads. Host-specific assemblies contained 65 460–72 405 contigs, representing 26 693–37 894 isogroups (∼genes) with an average N50 of 2254. Gene name and/or gene ontology annotations were possible for 58% of isogroups on average. Transcriptomes contained 93.1–94.3% of EuKaryotic Orthologous Groups comprising the core eukaryotic gene set, and 89.98–91.92% of the single-copy metazoan core gene set orthologs were complete, indicating fairly comprehensive assemblies. This work expands the complement of transcriptomic resources available for scleractinian coral species, including the first reference for a representative of Goniopora spp. as well as species with novel morphology. PMID:28938722

Novel transcriptome resources for three scleractinian coral species from the Indo-Pacific.

PubMed

Kenkel, Carly D; Bay, Line K

2017-09-01

Transcriptomic resources for coral species can provide insight into coral evolutionary history and stress-response physiology. Goniopora columna, Galaxea astreata, and Galaxea acrhelia are scleractinian corals of the Indo-Pacific, representing a diversity of morphologies and life-history traits. G. columna and G. astreata are common and cosmopolitan, while G. acrhelia is largely restricted to the coral triangle and Great Barrier Reef. Reference transcriptomes for these species were assembled from replicate colony fragments exposed to elevated (31°C) and ambient (27°C) temperatures. Trinity was used to create de novo assemblies for each species from 92-102 million raw Illumina Hiseq 2 × 150 bp reads. Host-specific assemblies contained 65 460-72 405 contigs, representing 26 693-37 894 isogroups (∼genes) with an average N50 of 2254. Gene name and/or gene ontology annotations were possible for 58% of isogroups on average. Transcriptomes contained 93.1-94.3% of EuKaryotic Orthologous Groups comprising the core eukaryotic gene set, and 89.98-91.92% of the single-copy metazoan core gene set orthologs were complete, indicating fairly comprehensive assemblies. This work expands the complement of transcriptomic resources available for scleractinian coral species, including the first reference for a representative of Goniopora spp. as well as species with novel morphology. © The Authors 2017. Published by Oxford University Press.

Recovery of temperature records from slow-growing corals by fine scale sampling of skeletons

NASA Astrophysics Data System (ADS)

Cohen, Anne L.; Thorrold, Simon R.

2007-09-01

We used laser ablation inductively coupled plasma mass spectrometry (LA ICP-MS) to analyze Sr/Ca ratios in 5 colonies of the Atlantic corals, Diploria labyrinthiformis and Montastrea franski, each growing less than 5 mm yr-1. By targeting the centers of septa we avoided thickening deposits to achieve an analytical sampling resolution of 5-10 days. The sensitivity of Sr/Ca to temperature (-0.096 mmol/mol/°C) is ˜3 times higher than previously reported for these species and equivalent to that exhibited by fast-growing Porites corals from the Indo-Pacific. The Sr/Ca-sea surface temperature (SST) calibrations derived from these corals were not statistically different and were independent of colony growth rate over the period studied. Data from 4 D. labyrinthiformis colonies were pooled to produce a single Sr/Ca-SST calibration with a calculated standard error on the predicted ocean temperature of ±0.51°C. Applying our calibration to Sr/Ca analyses of D. labyrinthiformis skeleton deposited in the late 18th century indicated that average annual sea surface temperatures around Bermuda were ˜1°C cooler than today.

Porites corals as recorders of mining and environmental impacts: Misima Island, Papua New Guinea

NASA Astrophysics Data System (ADS)

Fallon, Stewart J.; White, Jamie C.; McCulloch, Malcolm T.

2002-01-01

In 1989 open-cut gold mining commenced on Misima Island in Papua New Guinea (PNG). Open-cut mining by its nature causes a significant increase in sedimentation via the exposure of soils to the erosive forces of rain and runoff. This increased sedimentation affected the nearby fringing coral reef to varying degrees, ranging from coral mortality (smothering) to relatively minor short-term impacts. The sediment associated with the mining operation consists of weathered quartz feldspar, greenstone, and schist. These rocks have distinct chemical characteristics (rare earth element patterns and high abundances of manganese, zinc, and lead) and are entering the near-shore environment in considerably higher than normal concentrations. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), we analyzed eight colonies (two from high sedimentation, two transitional, two minor, and two unaffected control sites) for Y, La, Ce, Mn, Zn, and Pb. All sites show low steady background levels prior to the commencement of mining in 1988. Subsequently, all sites apart from the control show dramatic increases of Y, La, and Ce associated with the increased sedimentation as well as rapid decreases following the cessation of mining. The elements Zn and Pb exhibit a different behavior, increasing in concentration after 1989 when ore processing began and one year after initial mining operations. Elevated levels of Zn and Pb in corals has continued well after the cessation of mining, indicating ongoing transport into the reef of these metals via sulfate-rich waters. Rare earth element (REE) abundance patterns measured in two corals show significant differences compared to Coral Sea seawater. The corals display enrichments in the light and middle REEs while the heavy REEs are depleted relative to the seawater pattern. This suggests that the nearshore seawater REE pattern is dominated by island sedimentation. Trace element abundances of Misima Island corals clearly record

Mesophotic depths as refuge areas for fishery-targeted species on coral reefs

NASA Astrophysics Data System (ADS)

Lindfield, Steven J.; Harvey, Euan S.; Halford, Andrew R.; McIlwain, Jennifer L.

2016-03-01

Coral reefs are subjected to unprecedented levels of disturbance with population growth and climate change combining to reduce standing coral cover and stocks of reef fishes. Most of the damage is concentrated in shallow waters (<30 m deep) where humans can comfortably operate and where physical disturbances are most disruptive to marine organisms. Yet coral reefs can extend to depths exceeding 100 m, potentially offering refuge from the threats facing shallower reefs. We deployed baited remote underwater stereo-video systems (stereo-BRUVs) at depths of 10-90 m around the southern Mariana Islands to investigate whether fish species targeted by fishing in the shallows may be accruing benefits from being at depth. We show that biomass, abundance and species richness of fishery-targeted species increased from shallow reef areas to a depth of 60 m, whereas at greater depths, a lack of live coral habitat corresponded to lower numbers of fish. The majority of targeted species were found to have distributions that ranged from shallow depths (10 m) to depths of at least 70 m, emphasising that habitat, not depth, is the limiting factor in their vertical distribution. While the gradient of abundance and biomass versus depth was steepest for predatory species, the first species usually targeted by fishing, we also found that fishery-targeted herbivores prevailed in similar biomass and species richness to 60 m. Compared to shallow marine protected areas, there was clearly greater biomass of fishery-targeted species accrued in mesophotic depths. Particularly some species typically harvested by depth-limited fishing methods (e.g., spearfishing), such as the endangered humphead wrasse Cheilinus undulatus, were found in greater abundance on deeper reefs. We conclude that mesophotic depths provide essential fish habitat and refuge for fishery-targeted species, representing crucial zones for fishery management and research into the resilience of disturbed coral reef ecosystems.

Coral Pigments: Quantification Using HPLC and Detection by Remote Sensing

NASA Technical Reports Server (NTRS)

Cottone, Mary C.

1995-01-01

Widespread coral bleaching (loss of pigments of symbiotic dinoflagellates), and the corresponding decline in coral reef health worldwide, mandates the monitoring of coral pigmentation. Samples of the corals Porites compressa and P. lobata were collected from a healthy reef at Puako, Hawaii, and chlorophyll (chl) a, peridinin, and Beta-carotene (Beta-car) were quantified using reverse-phase high performance liquid chromatography (HPLC). Detailed procedures are presented for the extraction of the coral pigments in 90% acetone, and the separation, identification, and quantification of the major zooxanthellar pigments using spectrophotometry and a modification of the HPLC system described by Mantoura and Llewellyn (1983). Beta-apo-8-carotenal was found to be inadequate as in internal standard, due to coelution with chl b and/or chl a allomer in the sample extracts. Improvements are suggested, which may result in better resolution of the major pigments and greater accuracy in quantification. Average concentrations of peridinin, chl a, and Beta-car in corals on the reef were 5.01, 8.59, and 0.29, micro-grams/cm(exp 2), respectively. Average concentrations of peridinin and Beta-car did not differ significantly between the two coral species sampled; however, the mean chl a concentration in P. compressa specimens (7.81 ,micro-grams/cm(exp 2) was significantly lower than that in P. lobata specimens (9.96 11g/cm2). Chl a concentrations determined spectrophotometrically were significantly higher than those generated through HPLC, suggesting that spectrophotometry overestimates chl a concentrations. The average ratio of chl a-to-peridinin concentrations was 1.90, with a large (53%) coefficient of variation and a significant difference between the two species sampled. Additional data are needed before conclusions can be drawn regarding average pigment concentrations in healthy corals and the consistency of the chl a/peridinin ratio. The HPLC pigment concentration values

A sea water barrier to coral gene flow.

PubMed

Lessios, H A

2012-11-01

Land is not the only barrier to dispersal encountered by marine organisms. For sedentary shallow water species, there is an additional, marine barrier, 5000 km of uninterrupted deep-water stretch between the central and the eastern Pacific. This expanse of water, known as the ‘Eastern Pacific Barrier’, has been separating faunas of the two oceanic regions since the beginning of the Cenozoic. Species with larvae that cannot stay in the plankton for the time it takes to cross between the two sides have been evolving independently. That the eastern Pacific does not share species with the rest of the Pacific was obvious to naturalists two centuries ago (Darwin 1860). Yet, this rule has exceptions. A small minority of species are known to straddle the Eastern Pacific Barrier. One such exception is the scleractinian coral Porites lobata (Fig. 1). This species is spread widely throughout the Indo-Pacific, where it is one of the major reef-builders, but it is also encountered in the eastern Pacific. Are eastern and central Pacific populations of this coral connected by gene flow? In this issue of Molecular Ecology, Baums et al. (2012) use microsatellite data to answer this question. They show that P. lobata populations in the eastern Pacific are cut off from genetic influx from the rest of the Pacific. Populations within each of the two oceanic regions are genetically connected (though those in the Hawaiian islands are also isolated). Significantly, the population in the Clipperton Atoll, the westernmost island in the eastern Pacific, genetically groups with populations from the central Pacific, suggesting that crossing the Eastern Pacific Barrier by P. lobata propagules does occasionally occur.

Temporal consistency in background mortality of four dominant coral taxa along Australia's Great Barrier Reef

NASA Astrophysics Data System (ADS)

Pisapia, C.; Anderson, K. D.; Pratchett, M. S.

2016-09-01

Studies on the population and community dynamics of scleractinian corals typically focus on catastrophic mortality associated with acute disturbances (e.g., coral bleaching and outbreaks of crown-of-thorns starfish), though corals are subject to high levels of background mortality and injuries caused by routine and chronic processes. This study quantified prevalence (proportion of colonies with injuries) and severity (areal extent of injuries on individual colonies) of background mortality and injuries for four common coral taxa (massive Porites, encrusting Montipora, Acropora hyacinthus and branching Pocillopora) on the Great Barrier Reef, Australia. Sampling was conducted over three consecutive years during which there were no major acute disturbances. A total of 2276 adult colonies were surveyed across 27 sites, within nine reefs and three distinct latitudinal sectors. The prevalence of injuries was very high (>83%) across all four taxa, but highest for Porites (91%) and Montipora (85%). For these taxa ( Montipora and Pocillopora), there was also significant temporal and spatial variation in prevalence of partial mortality. The severity of injuries ranged from 3% to more than 80% and varied among coral taxa, but was fairly constant spatially and temporally. This shows that some injuries have considerable longevity and that corals may invest relatively little in regenerating tissue over sites of previous injuries. Inter-colony variation in the severity of injury also had no apparent effect on the realized growth of individual colonies, suggesting that energy diverted to regeneration has a limited bearing on overall energetic allocation, or impacts on other life-history processes (e.g., reproduction) rather than growth. Establishing background levels of injury and regeneration is important for understanding energy investment and life-history consequences for reef-building corals as well as for predicting susceptibility to, and capacity to recover from, acute

The microbiome of coral surface mucus has a key role in mediating holobiont health and survival upon disturbance

PubMed Central

Glasl, Bettina; Herndl, Gerhard J; Frade, Pedro R

2016-01-01

Microbes are well-recognized members of the coral holobiont. However, little is known about the short-term dynamics of mucus-associated microbial communities under natural conditions and after disturbances, and how these dynamics relate to the host's health. Here we examined the natural variability of prokaryotic communities (based on 16S ribosomal RNA gene amplicon sequencing) associating with the surface mucus layer (SML) of Porites astreoides, a species exhibiting cyclical mucus aging and shedding. Shifts in the prokaryotic community composition during mucus aging led to the prevalence of opportunistic and potentially pathogenic bacteria (Verrucomicrobiaceae and Vibrionaceae) in aged mucus and to a twofold increase in prokaryotic abundance. After the release of aged mucus sheets, the community reverted to its original state, dominated by Endozoicimonaceae and Oxalobacteraceae. Furthermore, we followed the fate of the coral holobiont upon depletion of its natural mucus microbiome through antibiotics treatment. After re-introduction to the reef, healthy-looking microbe-depleted corals started exhibiting clear signs of bleaching and necrosis. Recovery versus mortality of the P. astreoides holobiont was related to the degree of change in abundance distribution of the mucus microbiome. We conclude that the natural prokaryotic community inhabiting the coral SML contributes to coral health and that cyclical mucus shedding has a key role in coral microbiome dynamics. PMID:26953605

Species-specific control of external superoxide levels by the coral holobiont during a natural bleaching event

NASA Astrophysics Data System (ADS)

Diaz, Julia M.; Hansel, Colleen M.; Apprill, Amy; Brighi, Caterina; Zhang, Tong; Weber, Laura; McNally, Sean; Xun, Liping

2016-12-01

The reactive oxygen species superoxide (O2.-) is both beneficial and detrimental to life. Within corals, superoxide may contribute to pathogen resistance but also bleaching, the loss of essential algal symbionts. Yet, the role of superoxide in coral health and physiology is not completely understood owing to a lack of direct in situ observations. By conducting field measurements of superoxide produced by corals during a bleaching event, we show substantial species-specific variation in external superoxide levels, which reflect the balance of production and degradation processes. Extracellular superoxide concentrations are independent of light, algal symbiont abundance and bleaching status, but depend on coral species and bacterial community composition. Furthermore, coral-derived superoxide concentrations ranged from levels below bulk seawater up to ~120 nM, some of the highest superoxide concentrations observed in marine systems. Overall, these results unveil the ability of corals and/or their microbiomes to regulate superoxide in their immediate surroundings, which suggests species-specific roles of superoxide in coral health and physiology.

The origin and evolution of coral species richness in a marine biodiversity hotspot.

PubMed

Huang, Danwei; Goldberg, Emma E; Chou, Loke Ming; Roy, Kaustuv

2018-02-01

The Coral Triangle (CT) region of the Indo-Pacific realm harbors an extraordinary number of species, with richness decreasing away from this biodiversity hotspot. Despite multiple competing hypotheses, the dynamics underlying this regional diversity pattern remain poorly understood. Here, we use a time-calibrated evolutionary tree of living reef coral species, their current geographic ranges, and model-based estimates of regional rates of speciation, extinction, and geographic range shifts to show that origination rates within the CT are lower than in surrounding regions, a result inconsistent with the long-standing center of origin hypothesis. Furthermore, endemism of coral species in the CT is low, and the CT endemics are older than relatives found outside this region. Overall, our model results suggest that the high diversity of reef corals in the CT is largely due to range expansions into this region of species that evolved elsewhere. These findings strongly support the notion that geographic range shifts play a critical role in generating species diversity gradients. They also show that preserving the processes that gave rise to the striking diversity of corals in the CT requires protecting not just reefs within the hotspot, but also those in the surrounding areas. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Environmental controls on modern scleractinian coral and reef-scale calcification.

PubMed

Courtney, Travis A; Lebrato, Mario; Bates, Nicholas R; Collins, Andrew; de Putron, Samantha J; Garley, Rebecca; Johnson, Rod; Molinero, Juan-Carlos; Noyes, Timothy J; Sabine, Christopher L; Andersson, Andreas J

2017-11-01

Modern reef-building corals sustain a wide range of ecosystem services because of their ability to build calcium carbonate reef systems. The influence of environmental variables on coral calcification rates has been extensively studied, but our understanding of their relative importance is limited by the absence of in situ observations and the ability to decouple the interactions between different properties. We show that temperature is the primary driver of coral colony ( Porites astreoides and Diploria labyrinthiformis ) and reef-scale calcification rates over a 2-year monitoring period from the Bermuda coral reef. On the basis of multimodel climate simulations (Coupled Model Intercomparison Project Phase 5) and assuming sufficient coral nutrition, our results suggest that P. astreoides and D. labyrinthiformis coral calcification rates in Bermuda could increase throughout the 21st century as a result of gradual warming predicted under a minimum CO 2 emissions pathway [representative concentration pathway (RCP) 2.6] with positive 21st-century calcification rates potentially maintained under a reduced CO 2 emissions pathway (RCP 4.5). These results highlight the potential benefits of rapid reductions in global anthropogenic CO 2 emissions for 21st-century Bermuda coral reefs and the ecosystem services they provide.

A Reconstruction of Subtropical Western North Pacific SST Variability Back to 1578, Based on a Porites Coral Sr/Ca Record from the Northern Ryukyus, Japan

NASA Astrophysics Data System (ADS)

Kawakubo, Y.; Alibert, C.; Yokoyama, Y.

2017-12-01

We present a seasonal reconstruction of sea surface temperature (SST) from 1578 to 2008, based on a Porites coral Sr/Ca record from the northern Ryukyus, within the Kuroshio southern recirculation gyre. Interannual SST anomalies are generally 0.5°C, making Sr/Ca-derived SST reconstructions a challenging task. Replicate measurements along adjacent coral growth axes, enabled by the laser ablation inductively coupled plasma mass spectrometry technique used here, give evidence of rather large uncertainties. Nonetheless, derived winter SST anomalies are significantly correlated with the Western Pacific atmospheric pattern which has a dominant influence on winter temperature in East Asia. Annual mean SSTs show interdecadal variations, notably cold intervals between 1670 and 1700 during the Maunder Minimum (MM) and between 1766 and 1788 characterized by a negative phase of the North Atlantic Oscillation. Cold summers in 1783 and 1784 coincide with the long-lasting Laki eruption that had a profound impact on the Northern Hemisphere climate, including the severe "Tenmei" famine in Japan. The decades between 1855 and 1900 are significantly cooler than the first half of the twentieth century, while those between 1700 and 1765, following the MM, are warmer than average. SST variability in the Ryukyus is only marginally influenced by the Pacific Decadal Oscillation, so that external forcing remains the main driver of low-frequency temperature changes. However, the close connection between the Kuroshio extension (KE) and its recirculation gyre suggests that decadal SST anomalies associated with the KE front also impact the Ryukyus, and there is a possible additional role for feedback of the Kuroshio-Oyashio variability to the large-scale atmosphere at decadal timescale.

Assessing the ecological effects of human impacts on coral reefs in Bocas del Toro, Panama.

PubMed

Seemann, Janina; González, Cindy T; Carballo-Bolaños, Rodrigo; Berry, Kathryn; Heiss, Georg A; Struck, Ulrich; Leinfelder, Reinhold R

2014-03-01

Environmental and biological reef monitoring was conducted in Almirante Bay (Bahía Almirante) in Bocas del Toro, Panama, to assess impacts from anthropogenic developments. An integrated monitoring investigated how seasonal temperature stress, turbidity, eutrophication and physical impacts threatened reef health and biodiversity throughout the region. Environmental parameters such as total suspended solids [TSS], carbon isotopes (δ(13)C), C/N ratios, chlorophyll a, irradiance, secchi depth, size fractions of the sediments and isotope composition of dissolved inorganic carbon [DIC] of the water were measured throughout the years 2010 and 2011 and were analysed in order to identify different impact sources. Compared to data from Collin et al. (Smithsonian Contributions to the Marine Sciences 38:324-334, 2009) chlorophyll a has doubled at sites close to the city and the port Almirante (from 0.46-0.49 to 0.78-0.97 μg l(-1)) and suspension load increased, visible by a decrease in secchi depth values. Visibility decreased from 9-13 m down to 4 m at the bay inlet Boca del Drago, which is strongly exposed to river run off and dredging for the shipping traffic. Eutrophication and turbidity levels seemed to be the determining factor for the loss of hard coral diversity, most significant at chlorophyll a levels higher than 0.5 μg l(-1) and TSS levels higher than 4.7 mg l(-1). Hard coral cover within the bay has also declined, at some sites down to <10 % with extremely low diversities (7 hard coral species). The hard coral species Porites furcata dominated the reefs in highly impacted areas and showed a strong recovery after bleaching and a higher tolerance to turbidity and eutrophication compared to other hard coral species in the bay. Serious overfishing was detected in the region by a lack of adult and carnivorous fish species, such as grunts, snappers and groupers. Study sites less impacted by anthropogenic activities and/or those with local protection showed a

Species richness accelerates marine ecosystem restoration in the Coral Triangle.

PubMed

Williams, Susan L; Ambo-Rappe, Rohani; Sur, Christine; Abbott, Jessica M; Limbong, Steven R

2017-11-07

Ecosystem restoration aims to restore biodiversity and valuable functions that have been degraded or lost. The Coral Triangle is a hotspot for marine biodiversity held in its coral reefs, seagrass meadows, and mangrove forests, all of which are in global decline. These coastal ecosystems support valuable fisheries and endangered species, protect shorelines, and are significant carbon stores, functions that have been degraded by coastal development, destructive fishing practices, and climate change. Ecosystem restoration is required to mitigate these damages and losses, but its practice is in its infancy in the region. Here we demonstrate that species diversity can set the trajectory of restoration. In a seagrass restoration experiment in the heart of the Coral Triangle (Sulawesi, Indonesia), plant survival and coverage increased with the number of species transplanted. Our results highlight the positive role biodiversity can play in ecosystem restoration and call for revision of the common restoration practice of establishing a single target species, particularly in regions having high biodiversity. Coastal ecosystems affect human well-being in many important ways, and restoration will become ever more important as conservation efforts cannot keep up with their loss. Published under the PNAS license.

Development and Application of Sr/Ca-δ18O-Sea Surface Temperature calibrations for Last Glacial Maximum-Aged Isopora corals in the Great Barrier Reef

NASA Astrophysics Data System (ADS)

Brenner, L. D.; Linsley, B. K.; Potts, D. C.; Felis, T.; Mcgregor, H. V.; Gagan, M. K.; Inoue, M.; Tudhope, A. W.; Esat, T. M.; Thompson, W. G.; Tiwari, M.; Fallon, S.; Humblet, M.; Yokoyama, Y.; Webster, J.

2016-12-01

Isopora (Acroporidae) are sub-massive to massive corals found on most modern and fossil Indo-Pacific reefs. Despite their abundance, they are largely absent from the paleoceanographic literature but have the potential to provide proxy data where other commonly used corals, such as Porites, are sparse. The retrieval of Isopora fossils during International Ocean Discovery Program Leg 325 in the Great Barrier Reef (GBR) signaled the need to evaluate their possible paleoceanographic utility. We developed modern skeletal Sr/Ca- and δ18O-sea surface temperature (SST) calibrations for six modern Isopora colonies collected at Heron Island in the southern GBR. Pairing the coral Sr/Ca record with monthly SST data yielded Reduced Major Axis Sr/Ca- and δ18O-SST sensitivities of -0.054 mmol/mol/°C and -0.152 ‰/°C, respectively, falling within the range of published Porites values. We applied our Isopora-based regressions and previously published sensitivities from other species to a suite (n=37) of fossil samples collected from IODP 32. The calibrations produced a range of 3-7°C of warming, averaging 5°C, in the GBR from 22 ka to modern climate. This SST change is similar or slightly larger than other coral studies and larger than planktonic foraminifera Mg/Ca records. The planktonic Mg/Ca records from the Indonesian and Western Pacific Warm Pools indicate a warming of 3-3.5°C since 23ka (Linsley et al., 2010) while a fossil coral record from Tahiti indicates a warming of 3.2°C from 9.5ka to present (DeLong et al., 2010) and western Pacific coral records suggest a cooling of 5-6°C (Gagan et al., 2010; Guilderson et al., 1994: Beck et al., 1997), although these value might require rescaling (Gagan et al., 2012) resulting in slightly warmer temperature calculations. Our Isopora fossils from the GBR speak to the spatial heterogeneity of warming since the LGM and the continued need to develop more records for a more comprehensive understanding of the deglaciation.

Characterisation of an atypical manifestation of black band disease on Porites lutea in the Western Indian Ocean

PubMed Central

Wilkinson, David A.; Schleyer, Michael H.; Chabanet, Pascale; Quod, Jean-Pascal; Tortosa, Pablo

2016-01-01

Recent surveys conducted on Reunion Island coral reefs revealed an atypical manifestation of black band disease on the main framework building coral, Porites lutea. This BBD manifestation (PorBBD) presented a thick lighter-colored band, which preceded the typical BBD lesion. Whilst BBD aetiology has been intensively described worldwide, it remains unclear if corals with apparently similar lesions across coral reefs are affected by the same pathogens. Therefore, a multidisciplinary approach involving field surveys, gross lesion monitoring, histopathology and 454-pyrosequencing was employed to provide the first comprehensive characterization of this particular manifestation. Surveys conducted within two geomorphological zones over two consecutive summers and winters showed spatial and seasonal patterns consistent with those found for typical BBD. Genetic analyses suggested an uncharacteristically high level of Vibrio spp. bacterial infection within PorBBD. However, microscopic analysis revealed high densities of cyanobacteria, penetrating the compromised tissue as well as the presence of basophilic bodies resembling bacterial aggregates in the living tissue, adjacent to the bacterial mat. Additionally, classical BBD-associated cyanobacterial strains, genetically related to Pseudoscillatoria coralii and Roseofilum reptotaenium were identified and isolated and the presence of sulfate-reducers or sulfide-oxidizers such as Desulfovibrio and Arcobacter, previously shown to be associated with anoxic microenvironment within typical BBD was also observed, confirming that PorBBD is a manifestation of classical BBD. PMID:27441106

Historical Temperature Variability Affects Coral Response to Heat Stress

PubMed Central

Carilli, Jessica; Donner, Simon D.; Hartmann, Aaron C.

2012-01-01

Coral bleaching is the breakdown of symbiosis between coral animal hosts and their dinoflagellate algae symbionts in response to environmental stress. On large spatial scales, heat stress is the most common factor causing bleaching, which is predicted to increase in frequency and severity as the climate warms. There is evidence that the temperature threshold at which bleaching occurs varies with local environmental conditions and background climate conditions. We investigated the influence of past temperature variability on coral susceptibility to bleaching, using the natural gradient in peak temperature variability in the Gilbert Islands, Republic of Kiribati. The spatial pattern in skeletal growth rates and partial mortality scars found in massive Porites sp. across the central and northern islands suggests that corals subject to larger year-to-year fluctuations in maximum ocean temperature were more resistant to a 2004 warm-water event. In addition, a subsequent 2009 warm event had a disproportionately larger impact on those corals from the island with lower historical heat stress, as indicated by lower concentrations of triacylglycerol, a lipid utilized for energy, as well as thinner tissue in those corals. This study indicates that coral reefs in locations with more frequent warm events may be more resilient to future warming, and protection measures may be more effective in these regions. PMID:22479626

Assessing the effects of non-point source pollution on American Samoa's coral reef communities.

PubMed

Houk, Peter; Didonato, Guy; Iguel, John; Van Woesik, Robert

2005-08-01

Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels.

Coral-associated bacterial diversity is conserved across two deep-sea Anthothela species

USGS Publications Warehouse

Lawler, Stephanie N.; Kellogg, Christina A.; France, Scott C; Clostio, Rachel W; Brooke, Sandra D.; Ross, Steve W.

2016-01-01

Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp.) and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4-V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp.) had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont.

Toxicity of Deepwater Horizon Source Oil and the Chemical Dispersant, Corexit® 9500, to Coral Larvae

PubMed Central

Goodbody-Gringley, Gretchen; Wetzel, Dana L.; Gillon, Daniel; Pulster, Erin; Miller, Allison; Ritchie, Kim B.

2013-01-01

Acute catastrophic events can cause significant damage to marine environments in a short time period and may have devastating long-term impacts. In April 2010 the BP-operated Deepwater Horizon (DWH) offshore oil rig exploded, releasing an estimated 760 million liters of crude oil into the Gulf of Mexico. This study examines the potential effects of oil spill exposure on coral larvae of the Florida Keys. Larvae of the brooding coral, Porites astreoides, and the broadcast spawning coral, Montastraea faveolata, were exposed to multiple concentrations of BP Horizon source oil (crude, weathered and WAF), oil in combination with the dispersant Corexit® 9500 (CEWAF), and dispersant alone, and analyzed for behavior, settlement, and survival. Settlement and survival of P. astreoides and M. faveolata larvae decreased with increasing concentrations of WAF, CEWAF and Corexit® 9500, however the degree of the response varied by species and solution. P. astreoides larvae experienced decreased settlement and survival following exposure to 0.62 ppm source oil, while M. faveolata larvae were negatively impacted by 0.65, 1.34 and 1.5 ppm, suggesting that P. astreoides larvae may be more tolerant to WAF exposure than M. faveolata larvae. Exposure to medium and high concentrations of CEWAF (4.28/18.56 and 30.99/35.76 ppm) and dispersant Corexit® 9500 (50 and 100 ppm), significantly decreased larval settlement and survival for both species. Furthermore, exposure to Corexit® 9500 resulted in settlement failure and complete larval mortality after exposure to 50 and 100 ppm for M. faveolata and 100 ppm for P. astreoides. These results indicate that exposure of coral larvae to oil spill related contaminants, particularly the dispersant Corexit® 9500, has the potential to negatively impact coral settlement and survival, thereby affecting the resilience and recovery of coral reefs following exposure to oil and dispersants. PMID:23326298

Spatial and species variations in bacterial communities associated with corals from the Red Sea as revealed by pyrosequencing.

PubMed

Lee, On On; Yang, Jiangke; Bougouffa, Salim; Wang, Yong; Batang, Zenon; Tian, Renmao; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

2012-10-01

Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals.

Spatial and Species Variations in Bacterial Communities Associated with Corals from the Red Sea as Revealed by Pyrosequencing

PubMed Central

Lee, On On; Yang, Jiangke; Bougouffa, Salim; Wang, Yong; Batang, Zenon; Tian, Renmao; Al-Suwailem, Abdulaziz

2012-01-01

Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals. PMID:22865078

Heavy metal concentrations in growth bands of corals: a record of mine tailings input through time (Marinduque Island, Philippines).

PubMed

David, C P

2003-02-01

The impact of copper mining along the western coast of Marinduque Island was investigated. Historic input of mine tailings in the coastal region was traced through variations in heavy metal concentrations in Porites growth bands. Five samples were collected from three reefs showing different modes and extent of exposure to mine tailings. Baseline metal concentrations in Porites were established using a coral from a reef that is least exposed to contamination. The lowest mean values of Cu (0.7 microg/g), Mn (0.8 microg/g), and Zn (1.0 microg/g) were calculated from annual skeletal bands representing five years of growth. Conversely, a sample from a reef adjacent to an old tailings stockpile displayed consistently elevated metal values in its growth bands. Mean Cu, Mn, and Zn values for this coral are 3.1, 1.0 and 1.8 microg/g, respectively. Corals from the Ihatub reef showed a distinct metal concentration peak in their 1996 growth ring. These peaks coincide with a documented release of mine tailings in the Ihatub area during that year. Other metal peaks observed in coral samples correlate with years of high precipitation which may have resulted in increased sediment transport in the region. The metals are presumed to be mostly bound to the aragonite lattice of the coral skeleton, however, contribution from incorporated detrital materials to the observed metal signal (mainly of Fe) could not be easily discounted.

Development of laser ablation multi-collector inductively coupled plasma mass spectrometry for boron isotopic measurement in marine biocarbonates: new improvements and application to a modern Porites coral.

PubMed

Thil, François; Blamart, Dominique; Assailly, Caroline; Lazareth, Claire E; Leblanc, Thierry; Butsher, John; Douville, Eric

2016-02-15

Laser Ablation coupled to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICPMS) is a powerful tool for the high-precision measurement of the isotopic ratios of many elements in geological samples, with the isotope ratio ((11) B/(10) B) of boron being used as an indicator of the pH of oceanic waters. Most geological samples or standards are polished and ablation occurs on flat surfaces. However, the shape and the irregularities of marine biocarbonates (e.g., corals, foraminifera) can make precise isotopic measurements of boron difficult. Even after polishing, the porosity properties and the presence of holes or micro-fractures affect the signal and the isotopic ratio when ablating the material, especially in raster mode. The effect of porosity and of the crater itself on the (11) B signal and the isotopic ratio acquired by LA-MC-ICPMS in both raster and spot mode was studied. Characterization of the craters was then performed with an optical profilometer to determine their shapes and depths. Surface state effects were examined by analyzing the isotopic fractionation of boron in silicate (NIST-SRM 612 and 610 standards) and in carbonate (corals). Surface irregularities led to a considerable loss of signal when the crater depth exceeded 20 µm. The stability and precision were degraded when ablation occurred in a deep cavity. The effect of laser focusing and of blank correction was also highlighted and our observations indicate that the accuracy of the boron isotopic ratio does not depend on the shape of the surface. After validation of the analytical protocol for boron isotopes, a raster application on a Porites coral, which grew for 18 months in an aquarium after field sampling, was carried out. This original LA-MC-ICPMS study revealed a well-marked boron isotope ratio temporal variability, probably related to growth rate and density changes, irrespective of the pH of the surrounding seawater. Copyright © 2015 John Wiley & Sons, Ltd. Copyright

Biological review of 82 species of coral petitioned to be included in the Endangered Species Act

USGS Publications Warehouse

Brainard, Russell E.; Birkeland, Charles; Eakin, C. Mark; McElhany, Paul; Miller, Margaret W.; Patterson, Matt; Piniak, G.A.

2011-01-01

The BRT considered two major factors in conducting this review. The first factor was the interaction of natural phenomena and anthropogenic stressors that could potentially contribute to coral extinction. After extensive review of available scientific information, the BRT considers ocean warming, disease, and ocean acidification to be the most influential threats in posing extinction risks to the 82 candidate coral species between now and the year 2100. Threats of local origin but having widespread impact, such as sedimentation, nutrient enrichment, and fishing, were considered of medium importance in determining extinction risks. It is acknowledged that many other threats (e.g., physical damage from storms or ship groundings, invasive species or predator outbreaks, collection and trade) also negatively affect corals, often acutely and dramatically, but generally at relatively small local scales. These local threats were considered to be of limited scope and not deemed to contribute appreciably to the risk of species extinction, except in those special cases where species have restricted geographic or habitat ranges or species have already undergone precipitous population declines such that these local threats further contribute to depensatory processes that can magnify extinction risks (e.g., feedback-loops whereby individual survival decreases with smaller population size). The BRT acknowledges that local and global threats operate on different time scales and, though there is high confidence in the general progression of some key global threats, such as ocean warming and ocean acidification, there is much less certainty in the timing and spatial patterns of these threats. There is also substantial uncertainty in the abilities of the 82 candidate coral species to tolerate or adapt to each of the threats examined, as well as uncertainty in the dynamics of multiple simultaneous stresses. The BRT specifically identified increasing human population levels and the

Coral-Associated Bacterial Diversity Is Conserved across Two Deep-Sea Anthothela Species

PubMed Central

Lawler, Stephanie N.; Kellogg, Christina A.; France, Scott C.; Clostio, Rachel W.; Brooke, Sandra D.; Ross, Steve W.

2016-01-01

Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp.) and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4–V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp.) had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont. PMID:27092120

Coral-Associated Actinobacteria: Diversity, Abundance, and Biotechnological Potentials

PubMed Central

Mahmoud, Huda M.; Kalendar, Aisha A.

2016-01-01

Marine Actinobacteria, particularly coral-associated Actinobacteria, have attracted attention recently. In this study, the abundance and diversity of Actinobacteria associated with three types of coral thriving in a thermally stressed coral reef system north of the Arabian Gulf were investigated. Coscinaraea columna, Platygyra daedalea and Porites harrisoni have been found to harbor equivalent numbers of culturable Actinobacteria in their tissues but not in their mucus. However, different culturable actinobacterial communities have been found to be associated with different coral hosts. Differences in the abundance and diversity of Actinobacteria were detected between the mucus and tissue of the same coral host. In addition, temporal and spatial variations in the abundance and diversity of the cultivable actinobacterial communities were detected. In total, 19 different actinobacterial genera, namely Micrococcus, Brachybacterium, Brevibacterium, Streptomyces, Micromonospora, Renibacterium, Nocardia, Microbacterium, Dietzia, Cellulomonas, Ornithinimicrobium, Rhodococcus, Agrococcus, Kineococcus, Dermacoccus, Devriesea, Kocuria, Marmoricola, and Arthrobacter, were isolated from the coral tissue and mucus samples. Furthermore, 82 isolates related to Micromonospora, Brachybacterium, Nocardia, Micrococcus, Arthrobacter, Rhodococcus, and Streptomyces showed antimicrobial activities against representative Gram-positive and/or Gram-negative bacteria. Even though Brevibacterium and Kocuria were the most dominant actinobacterial isolates, they failed to show any antimicrobial activity, whereas less dominant genera, such as Streptomyces, did show antimicrobial activity. Focusing on the diversity of coral-associated Actinobacteria may help to understand how corals thrive under harsh environmental conditions and may lead to the discovery of novel antimicrobial metabolites with potential biotechnological applications. PMID:26973601

Temporal variation in photosynthetic pigments and UV-absorbing compounds in shallow populations of two Hawaiian reef corals

USGS Publications Warehouse

Kuffner, I.B.

2005-01-01

As we seek to understand the physiological mechanisms of coral bleaching, it is important to understand the background temporal variation in photosynthetic pigments and photoprotective compounds that corals exhibit. In this study, reef flat populations of two hermatypic coral species, Montipora capitata (Dana, 1846) and Porites compressa Dana, 1846, were sampled monthly in Kane'ohe Bay, Hawai'i, from January 1998 to March 1999. Surface ultraviolet radiation (UVR) was measured continually during this time period at the same location. High-performance liquid chromatography (HPLC) analysis of photosynthetic pigments and mycosporine-like amino acids (MAAs) revealed temporal changes in concentrations and proportions of these compounds in tissues of both species of coral. Chlorophyll a (chl a), chlorophyll c2 (chl c2), peridinin, and diadinoxanthin concentrations changed on a skeletal weight (M. capitata) or surface area (P. compressa) basis, significantly correlating with seasonal changes in solar input (number of days from the winter solstice). In P. compressa, diadinoxanthin increased in proportion to the total pigment pool during summer months, suggesting an up-regulation of a xanthophyll cycle. In M. capitata, the ratio of chl a: chl c2 decreased during winter months, suggesting photoacclimation to lower light levels. It is surprising that there was not a clear seasonal pattern in total MAA concentration for either species, with the exception of shinorine in P. compressa. The relative stability of MAA concentrations over the course of the year despite a pronounced seasonal trend in UVR suggests either that MAAs are not performing a photoprotective role in these species or that concentrations are kept at a threshold level in the presence of a dynamic light environment. ?? 2005 by University of Hawai'i Press All rights reserved.

Environmental controls on modern scleractinian coral and reef-scale calcification

PubMed Central

Courtney, Travis A.; Lebrato, Mario; Bates, Nicholas R.; Collins, Andrew; de Putron, Samantha J.; Garley, Rebecca; Johnson, Rod; Molinero, Juan-Carlos; Noyes, Timothy J.; Sabine, Christopher L.; Andersson, Andreas J.

2017-01-01

Modern reef-building corals sustain a wide range of ecosystem services because of their ability to build calcium carbonate reef systems. The influence of environmental variables on coral calcification rates has been extensively studied, but our understanding of their relative importance is limited by the absence of in situ observations and the ability to decouple the interactions between different properties. We show that temperature is the primary driver of coral colony (Porites astreoides and Diploria labyrinthiformis) and reef-scale calcification rates over a 2-year monitoring period from the Bermuda coral reef. On the basis of multimodel climate simulations (Coupled Model Intercomparison Project Phase 5) and assuming sufficient coral nutrition, our results suggest that P. astreoides and D. labyrinthiformis coral calcification rates in Bermuda could increase throughout the 21st century as a result of gradual warming predicted under a minimum CO2 emissions pathway [representative concentration pathway (RCP) 2.6] with positive 21st-century calcification rates potentially maintained under a reduced CO2 emissions pathway (RCP 4.5). These results highlight the potential benefits of rapid reductions in global anthropogenic CO2 emissions for 21st-century Bermuda coral reefs and the ecosystem services they provide. PMID:29134196

Shifts in bacterial communities of two caribbean reef-building coral species affected by white plague disease

PubMed Central

Cárdenas, Anny; Rodriguez-R, Luis M; Pizarro, Valeria; Cadavid, Luis F; Arévalo-Ferro, Catalina

2012-01-01

Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20 410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system. PMID:21955993

Latitudinal species diversity gradient of mushroom corals off eastern Australia: a baseline from the 1970s

NASA Astrophysics Data System (ADS)

Hoeksema, Bert W.

2015-11-01

Based on a study of mushroom coral species of eastern Australia, a decrease in species richness can be discerned from north to south. Eastern Australia, including the Great Barrier Reef (GBR), is one of only few coral reef areas suitable for studies on large-scale latitudinal biodiversity patterns. Such patterns may help to recognize biogeographic boundaries and factors regulating biodiversity. Owing to the eastern Australian long coastline, such studies are a logistic challenge unless reliable distribution data are already available, as in museum collections. A large coral collection predominantly sampled from this area in the 1970s is present in the Museum of Tropical Queensland (MTQ). The scleractinian family Fungiidae (mushroom corals), representing about 10% of Indo-Pacific reef coral species, was selected as proxy. It was represented by 1289 specimens belonging to 34 species with latitudinal ranges between 09°09‧S and 31°28‧S. The fauna of the northernmost reefs in the Gulf of Papua and the Torres Strait, and north of the Great Barrier Reef Marine Park (GBRMP), was represented by a maximum of 30 fungiids. From here a southward decline in species number was observed, down to Lord Howe Island with only one species. Together with previous records, the mushroom coral fauna of eastern Australia consists of 37 species, which is more diverse than hitherto known and similar to numbers found in the Coral Triangle. Future field surveys in the GBR should specifically target rarely known species, which are mainly small and found at depths >25 m. In the light of global climate change, they may also show whether previously recorded species are still present and whether their latitudinal ranges have shifted, using the 1970s records as a baseline.

Pulley reef: a deep photosynthetic coral reef on the West Florida Shelf, USA

USGS Publications Warehouse

Culter, J.K.; Ritchie, K.B.; Earle, S.A.; Guggenheim, D.E.; Halley, R.B.; Ciembronowicz, K.T.; Hine, A.C.; Jarrett, B.D.; Locker, S.D.; Jaap, W.C.

2006-01-01

Pulley Reef (24°50′N, 83°40′W) lies on a submerged late Pleistocene shoreline feature that formed during a sea-level stillstand from 13.8 to 14.5 ka (Jarrett et al. 2005). The reef is currently 60–75 m deep, exhibits 10–60% coral cover, and extends over approximately 160 km2 of the sea floor. Zooxanthellate corals are primarily Agaricia lamarcki, A. fragilis, Leptoseris cucullata, and less common Madracis formosa, M. pharensis, M. decactis, Montastraea cavernosa, Porites divaricata, Scolymia cubensis and Oculina tenella. Coralline algae are comparable in abundance to stony corals. Other macroalgae include Halimeda tuna, Dictyota divaricata, Lobophora variegata, Ventricatri ventricosa, Verdigelas pelas, and Kallymenia sp. Anadyomene menziesii is abundant. The reef provides a habitat for organisms typically observed at much shallower depths, and is the deepest known photosynthetic coral reef on the North America continental shelf (Fig. 1).

Phototropic growth in a reef flat acroporid branching coral species.

PubMed

Kaniewska, Paulina; Campbell, Paul R; Fine, Maoz; Hoegh-Guldberg, Ove

2009-03-01

Many terrestrial plants form complex morphological structures and will alter these growth patterns in response to light direction. Similarly reef building corals have high morphological variation across coral families, with many species also displaying phenotypic plasticity across environmental gradients. In particular, the colony geometry in branching corals is altered by the frequency, location and direction of branch initiation and growth. This study demonstrates that for the branching species Acropora pulchra, light plays a key role in axial polyp differentiation and therefore axial corallite development--the basis for new branch formation. A. pulchra branches exhibited a directional growth response, with axial corallites only developing when light was available, and towards the incident light. Field experimentation revealed that there was a light intensity threshold of 45 micromol m(-2) s(-1), below which axial corallites would not develop and this response was blue light (408-508 nm) dependent. There was a twofold increase in axial corallite growth above this light intensity threshold and a fourfold increase in axial corallite growth under the blue light treatment. These features of coral branch growth are highly reminiscent of the initiation of phototropic branch growth in terrestrial plants, which is directed by the blue light component of sunlight.

Spatial and Temporal Changes in Coral Community Responses to Ocean Warming

NASA Astrophysics Data System (ADS)

Barkley, H.; Cohen, A. L.

2016-02-01

Tropical Pacific sea surface temperature is projected to rise 2-3°C by the end of this century, fueling efforts to identify thermally-tolerant reef communities that have the best chance of surviving future climate change. We used skeletal indicators of thermal stress in massive Porites corals collected across the Palau archipelago to document spatial and temporal changes in community-scale tolerance to anomalous warm events associated with the 1998 and 2010 Pacific ENSOs. Within communities where bleaching was documented by visual surveys, we find a strong correlation between percent bleaching and the proportion of surviving Porites colonies exhibiting skeletal density anomalies or "stress bands". Using this relationship, we reconstructed the intensity and spatial patterns of bleaching during the 1998 ENSO event when survey data are limited. On exposed barrier reefs and inshore fringing reefs, the proportion of corals with 1998 stress bands (60% and 40% respectively) was consistent with that expected from DHW predictions and post-bleaching surveys. Conversely, in the Rock Island bays, where ambient temperatures were highest, no 1998 stress bands were recorded. However, these corals did respond to the 2010 thermal anomaly with the appearance of stress bands and an abrupt decline in calcification. The reasons for this apparent shift in thermal tolerance in response to the relatively weak 2010 warming are not yet clear. While the interplay of temperature with other environmental variables including light and flow cannot yet be ruled out, stressors associated with an increase in human activities, including tourism, on Palau are also considered.

Relationship between water and aragonite barium concentrations in aquaria reared juvenile corals

USGS Publications Warehouse

Gonneea, Meagan; Cohen, Anne L.; DeCarlo, Thomas M.; Charette, Matthew A.

2017-01-01

verification of these results for Porites species, which are widely used in paleo reconstructions.

Contact with turf algae alters the coral microbiome: contact versus systemic impacts

NASA Astrophysics Data System (ADS)

Pratte, Zoe A.; Longo, Guilherme O.; Burns, Andrew S.; Hay, Mark E.; Stewart, Frank J.

2018-03-01

Coral reefs are degrading to algae-dominated reefs worldwide, with alterations of coral microbiomes commonly co-occurring with reef demise. The severe thermal anomaly during the 2016 El Niño event in the South Pacific killed many corals and stressed others. We examined the microbiome of turf algae and of the coral Porites sp. in contact with turf during this thermal event to investigate algal turf effects on the coral microbiome during a period of environmental stress. The microbial composition of turf did not differ between coral-contacted and non-contacted turfs. However, microbiomes of corals in direct contact with turf were similar to those of the turf microbiome, but differed significantly from coral portions 5 cm from the point of turf/coral contact and from portions of the coral that looked most healthy, regardless of location. Although the majority of significant differences occurred in coral samples at the point of contact, a small subset of microbial taxa was enriched in coral tissues taken 5 cm from turf contact compared to all other sample types, including samples from areas of the coral that appeared most healthy. These results suggest that the coral microbiome is susceptible to colonization by microbes from turf, but not vice versa. Results also suggest that algal contact elicits a subtle shift in the coral microbiome just beyond the contact site. The combination of turf microbiome stability and coral microbiome vulnerability at areas of contact may contribute to the continued decline in coral cover and increase in algal cover associated with coral-algae phase shifts.

When environmental factors become stressors: interactive effects of vermetid gastropods and sedimentation on corals.

PubMed

Zill, Julie A; Gil, Michael A; Osenberg, Craig W

2017-03-01

Environmental stressors often interact, but most studies of multiple stressors have focused on combinations of abiotic stressors. Here we examined the potential interaction between a biotic stressor, the vermetid snail Ceraesignum maximum , and an abiotic stressor, high sedimentation, on the growth of reef-building corals. In a field experiment, we subjected juvenile massive Porites corals to four treatments: (i) neither stressor, (ii) sedimentation, (iii) vermetids or (iv) both stressors. Unexpectedly, we found no effect of either stressor in isolation, but a significant decrease in coral growth in the presence of both stressors. Additionally, seven times more sediment remained on corals in the presence (versus absence) of vermetids, likely owing to adhesion of sediments to corals via vermetid mucus. Thus, vermetid snails and high sedimentation can interact to drive deleterious effects on reef-building corals. More generally, our study illustrates that environmental factors can combine to have negative interactive effects even when individual effects are not detectable. Such 'ecological surprises' may be easily overlooked, leading to environmental degradation that cannot be anticipated through the study of isolated factors. © 2017 The Author(s).

Multi-species consumer jams and the fall of guarded corals to crown-of-thorns seastar outbreaks

PubMed Central

Kayal, Mohsen; Ballard, Jane; Adjeroud, Mehdi

2018-01-01

Outbreaks of predatory crown-of-thorns seastars (COTS) can devastate coral reef ecosystems, yet some corals possess mutualistic guardian crabs that defend against COTS attacks. However, guarded corals do not always survive COTS outbreaks, with the ecological mechanisms sealing the fate of these corals during COTS infestations remaining unknown. In August 2008 in Moorea (17.539° S, 149.830° W), French Polynesia, an unusually dense multi-species aggregation of predators was observed feeding upon guarded corals following widespread coral decline due to COTS predation. Concurrent assaults from these amplified, mixed-species predator guilds likely overwhelm mutualistic crab defense, ultimately leading to the fall of guarded corals. Our observations indicate that guarded corals can sustain devastating COTS attacks for an extended duration, but eventually concede to intensifying assaults from diverse predators that aggregate in high numbers as alternative prey decays. The fall of guarded corals is therefore suggested to be ultimately driven by an indirect trophic cascade that leads to amplified attacks from diverse starving predators following prey decline, rather than COTS assaults alone. PMID:29487739

Linking coral river runoff proxies with climate variability, hydrology and land-use in Madagascar catchments.

PubMed

Maina, Joseph; de Moel, Hans; Vermaat, Jan E; Bruggemann, J Henrich; Guillaume, Mireille M M; Grove, Craig A; Madin, Joshua S; Mertz-Kraus, Regina; Zinke, Jens

2012-10-01

Understanding the linkages between coastal watersheds and adjacent coral reefs is expected to lead to better coral reef conservation strategies. Our study aims to examine the main predictors of environmental proxies recorded in near shore corals and therefore how linked near shore reefs are to the catchment physical processes. To achieve these, we developed models to simulate hydrology of two watersheds in Madagascar. We examined relationships between environmental proxies derived from massive Porites spp. coral cores (spectral luminescence and barium/calcium ratios), and corresponding time-series (1950-2006) data of hydrology, climate, land use and human population growth. Results suggest regional differences in the main environmental drivers of reef sedimentation: on annual time-scales, precipitation, river flow and sediment load explained the variability in coral proxies of river discharge for the northeast region, while El Niño-Southern Oscillation (ENSO) and temperature (air and sea surface) were the best predictors in the southwest region. Copyright © 2012 Elsevier Ltd. All rights reserved.

Archaeal and Bacterial Communities Associated with the Surface Mucus of Caribbean Corals Differ in Their Degree of Host Specificity and Community Turnover Over Reefs.

PubMed

Frade, Pedro R; Roll, Katharina; Bergauer, Kristin; Herndl, Gerhard J

2016-01-01

Comparative studies on the distribution of archaeal versus bacterial communities associated with the surface mucus layer of corals have rarely taken place. It has therefore remained enigmatic whether mucus-associated archaeal and bacterial communities exhibit a similar specificity towards coral hosts and whether they vary in the same fashion over spatial gradients and between reef locations. We used microbial community profiling (terminal-restriction fragment length polymorphism, T-RFLP) and clone library sequencing of the 16S rRNA gene to compare the diversity and community structure of dominant archaeal and bacterial communities associating with the mucus of three common reef-building coral species (Porites astreoides, Siderastrea siderea and Orbicella annularis) over different spatial scales on a Caribbean fringing reef. Sampling locations included three reef sites, three reef patches within each site and two depths. Reference sediment samples and ambient water were also taken for each of the 18 sampling locations resulting in a total of 239 samples. While only 41% of the bacterial operational taxonomic units (OTUs) characterized by T-RFLP were shared between mucus and the ambient water or sediment, for archaeal OTUs this percentage was 2-fold higher (78%). About half of the mucus-associated OTUs (44% and 58% of bacterial and archaeal OTUs, respectively) were shared between the three coral species. Our multivariate statistical analysis (ANOSIM, PERMANOVA and CCA) showed that while the bacterial community composition was determined by habitat (mucus, sediment or seawater), host coral species, location and spatial distance, the archaeal community composition was solely determined by the habitat. This study highlights that mucus-associated archaeal and bacterial communities differ in their degree of community turnover over reefs and in their host-specificity.

Soft Coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) Species Diversity and Chemotypes

PubMed Central

Aratake, Satoe; Tomura, Tomohiko; Saitoh, Seikoh; Yokokura, Ryouma; Kawanishi, Yuichi; Shinjo, Ryuichi; Reimer, James Davis; Tanaka, Junichi; Maekawa, Hideaki

2012-01-01

Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus. PMID:22272344

Soft coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) species diversity and chemotypes.

PubMed

Aratake, Satoe; Tomura, Tomohiko; Saitoh, Seikoh; Yokokura, Ryouma; Kawanishi, Yuichi; Shinjo, Ryuichi; Reimer, James Davis; Tanaka, Junichi; Maekawa, Hideaki

2012-01-01

Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus.

Dynamics of coral-associated microbiomes during a thermal bleaching event.

PubMed

Pootakham, Wirulda; Mhuantong, Wuttichai; Putchim, Lalita; Yoocha, Thippawan; Sonthirod, Chutima; Kongkachana, Wasitthee; Sangsrakru, Duangjai; Naktang, Chaiwat; Jomchai, Nukoon; Thongtham, Nalinee; Tangphatsornruang, Sithichoke

2018-03-23

Coral-associated microorganisms play an important role in their host fitness and survival. A number of studies have demonstrated connections between thermal tolerance in corals and the type/relative abundance of Symbiodinium they harbor. More recently, the shifts in coral-associated bacterial profiles were also shown to be linked to the patterns of coral heat tolerance. Here, we investigated the dynamics of Porites lutea-associated bacterial and algal communities throughout a natural bleaching event, using full-length 16S rRNA and internal transcribed spacer sequences (ITS) obtained from PacBio circular consensus sequencing. We provided evidence of significant changes in the structure and diversity of coral-associated microbiomes during thermal stress. The balance of the symbiosis shifted from a predominant association between corals and Gammaproteobacteria to a predominance of Alphaproteobacteria and to a lesser extent Betaproteobacteria following the bleaching event. On the contrary, the composition and diversity of Symbiodinium communities remained unaltered throughout the bleaching event. It appears that the switching and/or shuffling of Symbiodinium types may not be the primary mechanism used by P. lutea to cope with increasing seawater temperature. The shifts in the structure and diversity of associated bacterial communities may contribute more to the survival of the coral holobiont under heat stress. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Site-specific variation in gene expression from Symbiodinium spp. associated with offshore and inshore Porites astreoides in the lower Florida Keys is lost with bleaching and disease stress

PubMed Central

Haslun, Joshua A.; Strychar, Kevin B.; Ostrom, Peggy H.; Cervino, James M.

2017-01-01

Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of Symbiodinium spp. from the coral Porites astreoides originating from an inshore and offshore reef in the Florida Keys. The acclimatization potential of Symbiodinium spp. to changing temperature regimes was also measured via a two-year reciprocal transplant between the sites. Offshore coral fragments displayed significantly higher expression in Symbiodinium spp. genes PCNA, SCP2, G3PDH, PCP and psaE than their inshore counterparts (p<0.05), a pattern consistent with increased bleaching susceptibility in offshore corals. Additionally, gene expression patterns in Symbiodinium spp. from site of origin were conserved throughout the two-year reciprocal transplant, indicating acclimatization did not occur within this multi-season time frame. Further, laboratory experiments were used to investigate the influence of acute high temperature (32°C for eight hours) and disease (lipopolysaccharide of Serratia marcescens) on the five metabolically related symbiont genes from the same offshore and inshore P. astreoides fragments. Gene expression did not differ between reef fragments, or as a consequence of acute exposure to heat or heat and disease, contrasting to results found in the field. Gene expression reported here indicates functional variation in populations of Symbiodinium spp. associated with P. astreoides in the Florida Keys, and is likely a result of localized adaptation. However, gene expression patterns observed in the lab imply that functional variation in zooxanthellae observed under conditions of chronic moderate stress is lost under the acute extreme conditions studied here. PMID:28355291

Site-specific variation in gene expression from Symbiodinium spp. associated with offshore and inshore Porites astreoides in the lower Florida Keys is lost with bleaching and disease stress.

PubMed

Salas, Briana Hauff; Haslun, Joshua A; Strychar, Kevin B; Ostrom, Peggy H; Cervino, James M

2017-01-01

Scleractinian coral are experiencing unprecedented rates of mortality due to increases in sea surface temperatures in response to global climate change. Some coral species however, survive high temperature events due to a reduced susceptibility to bleaching. We investigated the relationship between bleaching susceptibility and expression of five metabolically related genes of Symbiodinium spp. from the coral Porites astreoides originating from an inshore and offshore reef in the Florida Keys. The acclimatization potential of Symbiodinium spp. to changing temperature regimes was also measured via a two-year reciprocal transplant between the sites. Offshore coral fragments displayed significantly higher expression in Symbiodinium spp. genes PCNA, SCP2, G3PDH, PCP and psaE than their inshore counterparts (p<0.05), a pattern consistent with increased bleaching susceptibility in offshore corals. Additionally, gene expression patterns in Symbiodinium spp. from site of origin were conserved throughout the two-year reciprocal transplant, indicating acclimatization did not occur within this multi-season time frame. Further, laboratory experiments were used to investigate the influence of acute high temperature (32°C for eight hours) and disease (lipopolysaccharide of Serratia marcescens) on the five metabolically related symbiont genes from the same offshore and inshore P. astreoides fragments. Gene expression did not differ between reef fragments, or as a consequence of acute exposure to heat or heat and disease, contrasting to results found in the field. Gene expression reported here indicates functional variation in populations of Symbiodinium spp. associated with P. astreoides in the Florida Keys, and is likely a result of localized adaptation. However, gene expression patterns observed in the lab imply that functional variation in zooxanthellae observed under conditions of chronic moderate stress is lost under the acute extreme conditions studied here.

Spatial variability of initial 230Th/ 232Th in modern Porites from the inshore region of the Great Barrier Reef

NASA Astrophysics Data System (ADS)

Clark, Tara R.; Zhao, Jian-xin; Feng, Yue-xing; Done, Terry J.; Jupiter, Stacy; Lough, Janice; Pandolfi, John M.

2012-02-01

The main limiting factor in obtaining precise and accurate uranium-series (U-series) ages of corals that lived during the last few hundred years is the ability to constrain and correct for initial thorium-230 ( 230Th 0), which is proportionally much higher in younger samples. This is becoming particularly important in palaeoecological research where accurate chronologies, based on the 230Th chronometer, are required to pinpoint changes in coral community structure and the timing of mortality events in recent time (e.g. since European settlement of northern Australia in the 1850s). In this study, thermal ionisation mass spectrometry (TIMS) U-series dating of 43 samples of known ages collected from living Porites spp. from the far northern, central and southern inshore regions of the Great Barrier Reef (GBR) was performed to spatially constrain initial 230Th/ 232Th ( 230Th/ 232Th 0) variability. In these living Porites corals, the majority of 230Th/ 232Th 0 values fell within error of the conservative bulk Earth 230Th/ 232Th atomic value of 4.3 ± 4.3 × 10 -6 (2 σ) generally assumed for 230Th 0 corrections where the primary source is terrestrially derived. However, the results of this study demonstrate that the accuracy of 230Th ages can be further improved by using locally determined 230Th/ 232Th 0 values for correction, supporting the conclusion made by Shen et al. (2008) for the Western Pacific. Despite samples being taken from regions adjacent to contrasting levels of land modification, no significant differences were found in 230Th/ 232Th 0 between regions exposed to varying levels of sediment during river runoff events. Overall, 39 of the total 43 230Th/ 232Th 0 atomic values measured in samples from inshore reefs across the entire region show a normal distribution ranging from 3.5 ± 1.1 to 8.1 ± 1.1 × 10 -6, with a weighted mean of 5.76 ± 0.34 × 10 -6 (2 σ, MSWD = 8.1). Considering the scatter of the data, the weighted mean value with a more

Ten years after the crime: Lasting effects of damage from a cruise ship anchor on a coral reef in St. John, U.S. Virgin Islands

USGS Publications Warehouse

Rogers, C.S.; Garrison, V.H.

2001-01-01

In October 1988, a cruise ship dropped its anchor on a coral reef in Virgin Islands National Park, St. John, creating a distinct scar roughly 128 m long and 3 m wide from a depth of 22 m to a depth of 6 m. The anchor pulverized coral colonies and smashed part of the reef framework. In April 1991, nine permanent quadrats (1 m2) were established inside the scar over a depth range of 9 m to 12.5 m. At that time, average coral cover inside the scar was less than 1%. These quadrats were surveyed again in 1992, 1993, 1994, 1995 and 1998. Recruits of 19 coral species have been observed, with Agaricia agaricites and Porites spp. the most abundant. Quadrats surveyed outside the scar in June 1994 over the same depth range had a higher percent coral cover (mean = 7.4%, SD = 4.5) and greater average size (maximum length) of coral colonies than in quadrats inside the damaged area. Although coral recruits settle into the scar in high densities, live coral cover has not increased significantly in the last 10 yrs, reflecting poor survival and growth of newly settled corals. The relatively planar aspect of the scar may increase the vulnerability of the recruits to abrasion and mortality from shifting sediments. Ten years after the anchor damage occurred, live coral cover in the still-visible scar (mean = 2.6%, SD = 2.7) remains well below the cover found in the adjacent, undamaged reef.

Do the shuffle: Changes in Symbiodinium consortia throughout juvenile coral development

PubMed Central

Reich, Hannah G.; Robertson, Deborah L.; Goodbody-Gringley, Gretchen

2017-01-01

Previous studies of symbiotic associations between scleractinians corals and Symbiodinium have demonstrated that the consortium of symbionts can change in response to environmental conditions. However, less is known about symbiont shuffling during early coral development, particularly in brooding species. This study examined whether Symbiodinium consortia (1) varied in Porites astreoides on shallow (10m) and upper mesophotic (30m) reefs, (2) changed during coral development, and (3) influenced growth of juveniles in different environments. Symbiodinium ITS2 sequences were amplified using universal primers and analyzed using phylotype-specific primers designed for phylotypes A, B, and C. Adults from both depths were found to host only phylotype A, phylotypes A and B, or phylotypes A, B, and C and the frequency of the phylotype composition did not vary with depth. However, phylotype A was the dominant symbiont that was vertically transmitted to the planulae. The presence of phylotypes B and C was detected in the majority of juveniles when transplanted onto the shallow and upper mesophotic reefs whereas only phylotype A was detected in the majority of juveniles reared in outdoor aquaria. In addition, growth of juvenile P. astreoides harboring different combinations of Symbiodinium phylotypes did not vary when transplanted to different reef zones. However, juveniles reared in in situ reef environments grew faster than those reared in ex situ outdoor aquaria. These results show that Symbiodinium consortia change during development of P. astreoides and are influenced by environmental conditions. PMID:28182684

A Possible Role for Vitamin C in Coral Calcification

NASA Astrophysics Data System (ADS)

Rosenthal, J. J.; Roberson, L.; Vazquez, N.

2016-02-01

Despite the importance of coral reefs to tropical, marine ecosystems, the biological components of the calcification process are poorly understood. Because calcification must involve the delivery of organic and inorganic components across cell membranes, we postulate that it has similar features to epithelial and neuronal transport mechanisms in vertebrates. Accordingly, we are interested in identifying the specific membrane transporters underlying skeleton formation. As a model, we are using larvae from the ubiquitous Caribbean species Porites astreoides, a rapidly growing stony coral that is resistant to anthropogenic stressors. Using Illumina RNAseq, we assembled a larval transcriptome and compared gene expression between swimming larvae and recently settled ones that had just commenced the process of calcification. As expected, we identified many ion transporter, pump and channel transcripts that were upregulated in settled larvae. It was surprising, however, to find that the most upregulated transcript appeared to encode a Na-dependent Vitamin C transporter (SLC23A). In vertebrates, SLC23A transporters play a vital role in bone morphogenesis where Vitamin C is an essential cofactor for enzymes that condition collagen precursors for assembly into mature molecules. In corals, collagen has been identified as a component of the skeleton's extracellular matrix. Using in situ hybridization, we showed that the P. astreoides SLC23A messages were expressed in regions adjacent to rapid skeleton formation, on the aboral surface and septa of settled larvae. To confirm that the coral clone is indeed a Vitamin C transporter, we expressed it in Xenopus oocytes and studied its activity using voltage-clamp. Preliminary data demonstrate that it induces a current that is activated by Na and Vitamin C. This approach will help us better understand the molecular mechanisms underlying calcification and how they might respond to environmental change.

Coral calcification in a changing World and the interactive dynamics of pH and DIC upregulation

NASA Astrophysics Data System (ADS)

McCulloch, Malcolm T.; D'Olivo, Juan Pablo; Falter, James; Holcomb, Michael; Trotter, Julie A.

2017-05-01

Coral calcification is dependent on the mutualistic partnership between endosymbiotic zooxanthellae and the coral host. Here, using newly developed geochemical proxies (δ11B and B/Ca), we show that Porites corals from natural reef environments exhibit a close (r2 ~0.9) antithetic relationship between dissolved inorganic carbon (DIC) and pH of the corals' calcifying fluid (cf). The highest DICcf (~ × 3.2 seawater) is found during summer, consistent with thermal/light enhancement of metabolically (zooxanthellae) derived carbon, while the highest pHcf (~8.5) occurs in winter during periods of low DICcf (~ × 2 seawater). These opposing changes in DICcf and pHcf are shown to maintain oversaturated but stable levels of carbonate saturation (Ωcf ~ × 5 seawater), the key parameter controlling coral calcification. These findings are in marked contrast to artificial experiments and show that pHcf upregulation occurs largely independent of changes in seawater carbonate chemistry, and hence ocean acidification, but is highly vulnerable to thermally induced stress from global warming.

Spatial and Seasonal Calcification in Corals and Calcareous Crusts in a Naturally Warm Coral Reef Region

NASA Astrophysics Data System (ADS)

Roik, A.; Roder, C.; Roethig, T.; Voolstra, C. R.

2016-02-01

The Red Sea harbors highly diverse and structurally complex coral reefs and is of interest for ocean warming studies. In the central and southern part, water temperatures rise above 30°C during summer, constituting one of the warmest coral reef environments worldwide. Additionally, seasonal variability of temperatures allows studying changes of environmental conditions and their effects on coral reef processes. To explore the influence of these warm and seasonally variable habitats on reef calcification, we measured in situ calcification of primary and secondary reef-builders in the central Red Sea. We collected calcification rates on the major habitat-forming coral genera Porites, Acropora, and Pocillopora, and also on calcareous crusts (CC). The study comprised forereef and backreef environments of three reefs along a cross-shelf gradient assessed over four seasons of the year. Calcification patterns of all coral genera were consistent across the shelf and highest in spring. In contrast to the corals, CC calcification strongly increased with distance from shore, but varied to a lesser extend over the seasons demonstrating lower calcification rates during spring and summer. Interestingly, reef calcification rates in the central Red Sea were on average in the range of data reported from the Caribbean and Indo-Pacific. For Acropora, annual average calcification rates were even at the lower end in comparison to studies from other locations. While coral calcification maxima typically have been observed during summer in many reef locations worldwide, we observed calcification maxima during spring in the central Red Sea indicating that summer temperatures may exceed the optima of reef calcifiers. Our study provides a baseline of calcification data for the region and serves as a foundation for comparative efforts to quantify the impact of future environmental change.

Volcanic Acidification of a Coral Reef at Maug Island: Influences on Biological Processes and Ecosystem Structure

NASA Astrophysics Data System (ADS)

Enochs, I.; Manzello, D.; Donham, E. M.; Johnston, L.; Valentino, L.; Young, C.; Kolodziej, G.; Carlton, R.; Price, N.

2016-02-01

Coral reef ecosystems are expected to be strongly impacted by ocean acidification (OA) in the coming century. The influences of OA on coral reefs will be numerous, involving diverse species with different degrees of susceptibility. Naturally acidified systems provide a way to study these individual responses and a means to investigate how myriad alterations manifest at the ecosystem-scale over long periods of time. To this end, we characterized the unique coral reef ecosystem surrounding the volcanic carbon dioxide vent at Maug Island in the Commonwealth of the Northern Mariana Islands (CNMI). We present data on the spatial extent of carbonate chemistry alteration through interpolation of water bottle samples, and data on the temporal nature of this gradient through the deployment of three SeaFET pH loggers over a period of three months. We analyze trace-gas concentrations and characterize fluctuations in light, current, tides, and temperature. We tie these environmental data to high-resolution photo mosaics and in situ biodiversity surveys to examine changes in reef community structure correlated with this natural OA gradient. Finally, we investigate the influence of vent proximity on biological processes affecting reef habitat growth and erosion. Using computed tomography (CT) and analysis of coral growth bands, we analyze changes in the calcification of massive Porites coral. Using crystalline calcium carbonate (calcite) blocks, we quantify the settlement and erosion rate of microboring algae. Together these measurements underscore the strong influence that OA will have on reef persistence and highlight the value of the Maug site for future OA research.

Modeling Surface Water Transport in the Central Pacific Ocean With 129I Records From Coral Skeletons

NASA Astrophysics Data System (ADS)

Beck, W.; Biddulph, D. L.; Russell, J. L.; Burr, G. S.; Jull, T. J.; Correge, T.; Roeder, B.

2008-12-01

129I occurs naturally in extremely low abundance via cosmic ray interactions in the atmosphere as well as by spontaneous fission of uranium. Oceanic concentrations of 129I have risen by several orders of magnitude during the last half century largely from environmental pollution coming from several point-source nuclear fuel reprocessing plants. In the Pacific basin, much of the increase has apparently come from the Hanford Nuclear reprocessing plant in the United States, with iodine primarily arriving via the Columbia River. Coral skeletons preserve records of 129I concentration of the surface waters from which they were deposited, yielding records with annual resolution or better. We will present three such records from different locations in the Pacific Ocean: the Solomon Islands, Easter Island and Clipperton Atoll. For this study, drill cores from living massive coral skeletons of the species Porites Lobata were collected from these sites. 129I/127I values were measured using accelerator mass spectrometry (AMS) at the University of Arizona with an NEC 3 MV Pelletron accelerator. Results from the analysis of the corals will be compared to the distribution of other mixed-layer tracers (chloro-fluorocarbons and tritium) collected during the World Ocean Circulation Experiment cruises conducted between 1990 and 2002. The 129I/127I records observed in these corals will also be compared to tracer transit time calculations determined from a 20th century simulation of the GFDL coupled-climate passive-tracer model.

Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century

PubMed Central

van Woesik, R.; Golbuu, Y.; Roff, G.

2015-01-01

Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are ‘keeping up’ with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6–8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially ‘keep up’ with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low–mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m−2), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century. PMID:26587277

Current status of coral reefs in the United Arab Emirates: Distribution, extent, and community structure with implications for management.

PubMed

Grizzle, Raymond E; Ward, Krystin M; AlShihi, Rashid M S; Burt, John A

2016-04-30

Coral reefs of the United Arab Emirates were once extensive, but have declined dramatically in recent decades. Marine management and policy have been hampered by outdated and inaccurate habitat maps and habitat quality information. We combined existing recent datasets with our newly mapped coral habitats to provide a current assessment of nation-wide extent, and performed quantitative surveys of communities at 23 sites to assess coral cover and composition. Over 132 km(2) of coral habitat was mapped, averaging 28.6 ± 3.8% live coral cover at surveyed sites. In the Arabian Gulf low cover, low richness Porites dominated communities characterized western Abu Dhabi, while reefs northeast of Abu Dhabi city generally contained higher richness and cover, and were dominated by merulinids (formerly faviids). Distinct communities occur in the Sea of Oman, where cover and richness were low. We provide management recommendations to enhance conservation of vulnerable coral reefs in the UAE. Copyright © 2015 Elsevier Ltd. All rights reserved.

Responses of calcification of massive and encrusting corals to past, present, and near-future ocean carbon dioxide concentrations.

PubMed

Iguchi, Akira; Kumagai, Naoki H; Nakamura, Takashi; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

2014-12-15

In this study, we report the acidification impact mimicking the pre-industrial, the present, and near-future oceans on calcification of two coral species (Porites australiensis, Isopora palifera) by using precise pCO2 control system which can produce acidified seawater under stable pCO2 values with low variations. In the analyses, we performed Bayesian modeling approaches incorporating the variations of pCO2 and compared the results between our modeling approach and classical statistical one. The results showed highest calcification rates in pre-industrial pCO2 level and gradual decreases of calcification in the near-future ocean acidification level, which suggests that ongoing and near-future ocean acidification would negatively impact coral calcification. In addition, it was expected that the variations of parameters of carbon chemistry may affect the inference of the best model on calcification responses to these parameters between Bayesian modeling approach and classical statistical one even under stable pCO2 values with low variations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Considering Species Tolerance to Climate Change in Conservation Management at Little Cayman's Coral Reefs

NASA Astrophysics Data System (ADS)

Camp, E.; Manfrino, C.; Smith, D.; Suggett, D.

2013-05-01

There is growing evidence demonstrating that climate change, notably increased frequency and intensity of thermal anomalies combined with ocean acidification, will negatively impact the future growth and viability of many reef systems, including those in the Caribbean. One key question that remains unanswered is whether or not there are management options aimed at protecting coral species from these threats. Little Cayman (Cayman Islands) provides a rare opportunity to investigate global climate stressors without the confounding impact of local anthropogenic stressors. Our research has focused on two climate change issues: Firstly, we have identified species-specific coral bleaching susceptibility (and the influence of regulation upon this susceptibility) to thermal anomalies. Species level of vulnerability to thermal anomalies can decrease when grown under variable temperature. Environmental variability may be key in influencing the susceptibility of corals to stress. The second part of our research has therefore addressed the variability in inorganic carbon chemistry that naturally occurs where certain reef building corals exist. We have identified how the inorganic carbon chemistry varies naturally among habitats and thus how corals within these habitats are potentially adapted to future acidification. Spatial, diurnal, lunar and seasonal variability have been identified as important factors with pCO2 values of up to 700-800 μatm and pH values as low as 7.801 for lagoon habitats, showing that some species are already being exposed to typical pCO2 and pH levels expected for the oceans in ~50 years' time. Using an eco-physiological approach, we are exploring how some reef-building corals are able to acclimate to more variable chemistry compared to others and whether this natural capacity installs increased tolerance to future acidification. These eco-physiological studies provide important information that can be utilized in a management framework. The aim of

Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages

PubMed Central

Waheed, Zarinah; van Mil, Harald G. J.; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W.

2015-01-01

The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park. PMID:26719987

Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages.

PubMed

Waheed, Zarinah; van Mil, Harald G J; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W

2015-01-01

The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park.

[Live coral predation by fish in Tayrona Nature National Park, Colombian Caribbean].

PubMed

Reyes-Nivia, María Catalina; Garzón-Ferreira, Jaime; Rodríguez-Ramírez, Alberto

2004-12-01

Live coral predation by fish was evaluated in two bays of the Tayrona National Natural Park (Colombia), as a possible biological agent causing coral mortality. Visual censuses were used to identify the most important predator. Predation incidence was determined by examining all colonies present in permanent belt transects (20 x 2 m) in two reef environments (one dominated by Colpophyllia natans and the other one by Montastraea faveolata), for two climatic seasons (rainy and dry seasons). The parrotfish Sparisoma viride was the most important predator due to its biting frequency and bite size. S. viride adults of the initial and terminal phases, removed live tissue and part of the calcareous matrix of M. faveolata, M. annularis, Porites astreoides and C. natans, of which, the last one lost a major amount of tissue per area (3.51 cm2) and volume (3.22 cm3) per bite. A negative exponential tendency (r2=0.94), between coral density and volume removed was found, indicating that the coral density determines the bite's damage. There is no clear relationship between predation incidence and climatic seasons at the sites studied. At Chengue and Gayraca bays, live coral predation is one of the factors contributing to coral tissue loss and could have important consequences on the dynamic of these reefs.

Seaweed allelopathy against coral: surface distribution of a seaweed secondary metabolite by imaging mass spectrometry.

PubMed

Andras, Tiffany D; Alexander, Troy S; Gahlena, Asiri; Parry, R Mitchell; Fernandez, Facundo M; Kubanek, Julia; Wang, May D; Hay, Mark E

2012-10-01

Coral reefs are in global decline, with seaweeds increasing as corals decrease. Although seaweeds inhibit coral growth, recruitment, and survivorship, the mechanism of these interactions is poorly understood. Here, we used field experiments to show that contact with four common seaweeds induces bleaching on natural colonies of Porites rus. Controls in contact with inert, plastic mimics of seaweeds did not bleach, suggesting seaweed effects resulted from allelopathy rather than shading, abrasion, or physical contact. Bioassay-guided fractionation of the hydrophobic extract from the red alga Phacelocarpus neurymenioides revealed a previously characterized antibacterial metabolite, neurymenolide A, as the main allelopathic agent. For allelopathy of lipid-soluble metabolites to be effective, the compounds would need to be deployed on algal surfaces where they could transfer to corals on contact. We used desorption electrospray ionization mass spectrometry (DESI-MS) to visualize and quantify neurymenolide A on the surface of P. neurymenioides, and we found the molecule on all surfaces analyzed, with highest concentrations on basal portions of blades.

Coral Diseases Following Massive Bleaching in 2005 Cause 60 Percent Decline in Coral Cover and Mortality of the Threatened Species, Acropora Palmata, on Reefs in the U.S. Virgin Islands

USGS Publications Warehouse

Rogers, Caroline S.

2008-01-01

Record-high seawater temperatures and calm seas in the summer of 2005 led to the most severe coral bleaching (greater than 90 percent bleached coral cover) ever observed in the U.S. Virgin Islands (USVI) (figs. 1 and 2). All but a few coral species bleached, including the threatened species, Acropora palmata. Bleaching was seen from the surface to depths over 20 meters.

Assessment of the Coral Temperature Proxies for Orbicella faveolata in the Southwestern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Vara, M. A.; DeLong, K. L.; Herrmann, A. D.; Ouellette, G., Jr.; Richey, J. N.

2017-12-01

Coral Sr/Ca is a robust proxy of sea surface temperature (SST); however, discrepancies in the Sr/Ca-SST relationship among colonies of the same species may reduce confidence in absolute temperature reconstructions. Furthermore, terrestrial carbonate weathering can provide local sources of Sr and/or Ca to coastal waters that may disrupt the temperature-based coral Sr/Ca signal. Thus other trace metal SST proxies have been suggested to circumvent these issues (Li/Ca, Li/Mg, and Sr-U). Coral Ba/Ca has been used as a proxy for runoff and coastal upwelling, and therefore may be used to identify intervals when these processes overprint the Sr/Ca-SST signal. This study tests multiple coral SST proxies using reproducibility assessments to determine the best performing SST proxy. We conduct these assessments with cores recovered in 1991 by the U.S. Geological Survey from five Orbicella faveolata colonies from three reefs offshore of Veracruz, Mexico (19.06°N, 96.93°W) in water depths varying from 3 to 12 m. Previous studies found micromilling the complex skeletal structure of O. faveolata challenging and that monthly resolution may not recover full seasonal cycles. We use a laser ablation inductively coupled plasma mass spectrometer to simultaneously sample this coral's structure at weekly intervals spanning 8 years for Li/Ca, Li/Mg, Sr-U, Sr/Ca, and Ba/Ca. Here we found coral Li/Ca means and seasonal variations are similar among colonies thus this proxy may capture absolute temperature and SST variability. Similar to previous research with Porites corals, Li/Ca in these O. faveolata corals decreases with increases in SST with similar slopes and intercepts. During the last 10 years of these corals' lives, coral Sr/Ca analysis reveals a mean shift among colonies suggesting an external source could have disrupted the Sr/Ca signal, possibly seasonal runoff and/or winter upwelling common to Veracruz waters. Coral Ba/Ca analyses reveals elevated values in winters that coincide

The Presence of Biomarker Enzymes of Selected Scleractinian Corals of Palk Bay, Southeast Coast of India

PubMed Central

Anithajothi, R.; Duraikannu, K.; Umagowsalya, G.; Ramakritinan, C. M.

2014-01-01

The health and existence of coral reefs are in danger by an increasing range of environmental and anthropogenic impacts. The causes of coral reef decline include worldwide climate change, shoreline development, habitat destruction, pollution, sedimentation and overexploitation. These disasters have contributed to an estimated loss of 27% of the reefs. If the current pressure continues unabated, the estimated loss of coral reef will be about 60% by the year 2030. Therefore, the present study was aimed to analyze the enzymes involved in stress induced by coral pathogen and its resistance. We focused on the enzymes involved in melanin synthesis pathway (phenoloxidase (PO) and peroxidases (POD)) and free radical scavenging enzymes (super oxide dismutase (SOD), catalase (CAT)) and glutathione peroxidase (Gpx) in selected scleractinian corals such as Acropora formosa, Echinopora lamellosa, Favia favus, Favites halicora, Porites sp., and Anacropora forbesi. Overall, PO activity of coral was significantly lower than that of zooxanthellae except for Favia favus. Coral colonies with lower PO and POD activities are prone to disease. Maximum antioxidant defensive enzymes were observed in Favia favus followed by Echinopora lamellose. It is concluded that assay of these enzymes can be used as biomarkers for identifying the susceptibility of corals towards coral bleaching induced by pathogen. PMID:25215288

The presence of biomarker enzymes of selected Scleractinian corals of Palk Bay, southeast coast of India.

PubMed

Anithajothi, R; Duraikannu, K; Umagowsalya, G; Ramakritinan, C M

2014-01-01

The health and existence of coral reefs are in danger by an increasing range of environmental and anthropogenic impacts. The causes of coral reef decline include worldwide climate change, shoreline development, habitat destruction, pollution, sedimentation and overexploitation. These disasters have contributed to an estimated loss of 27% of the reefs. If the current pressure continues unabated, the estimated loss of coral reef will be about 60% by the year 2030. Therefore, the present study was aimed to analyze the enzymes involved in stress induced by coral pathogen and its resistance. We focused on the enzymes involved in melanin synthesis pathway (phenoloxidase (PO) and peroxidases (POD)) and free radical scavenging enzymes (super oxide dismutase (SOD), catalase (CAT)) and glutathione peroxidase (Gpx) in selected scleractinian corals such as Acropora formosa, Echinopora lamellosa, Favia favus, Favites halicora, Porites sp., and Anacropora forbesi. Overall, PO activity of coral was significantly lower than that of zooxanthellae except for Favia favus. Coral colonies with lower PO and POD activities are prone to disease. Maximum antioxidant defensive enzymes were observed in Favia favus followed by Echinopora lamellose. It is concluded that assay of these enzymes can be used as biomarkers for identifying the susceptibility of corals towards coral bleaching induced by pathogen.

Coral Skeletons Provide Historical Evidence of Phosphorus Runoff on the Great Barrier Reef

PubMed Central

Mallela, Jennie; Lewis, Stephen E.; Croke, Barry

2013-01-01

Recently, the inshore reefs of the Great Barrier Reef have declined rapidly because of deteriorating water quality. Increased catchment runoff is one potential culprit. The impacts of land-use on coral growth and reef health however are largely circumstantial due to limited long-term data on water quality and reef health. Here we use a 60 year coral core record to show that phosphorus contained in the skeletons (P/Ca) of long-lived, near-shore Porites corals on the Great Barrier Reef correlates with annual records of fertiliser application and particulate phosphorus loads in the adjacent catchment. Skeletal P/Ca also correlates with Ba/Ca, a proxy for fluvial sediment loading, again linking near-shore phosphorus records with river runoff. Coral core records suggest that phosphorus levels increased 8 fold between 1949 and 2008 with the greatest levels coinciding with periods of high fertiliser-phosphorus use. Periods of high P/Ca correspond with intense agricultural activity and increased fertiliser application in the river catchment following agricultural expansion and replanting after cyclone damage. Our results demonstrate how coral P/Ca records can be used to assess terrestrial nutrient loading of vulnerable near-shore reefs. PMID:24086606

UV-absorbing bacteria in coral mucus and their response to simulated temperature elevations

NASA Astrophysics Data System (ADS)

Ravindran, J.; Kannapiran, E.; Manikandan, B.; Francis, K.; Arora, Shruti; Karunya, E.; Kumar, Amit; Singh, S. K.; Jose, Jiya

2013-12-01

Reef-building corals encompass various strategies to defend against harmful ultraviolet (UV) radiation. Coral mucus contains UV-absorbing compounds and has rich prokaryotic diversity associated with it. In this study, we isolated and characterized the UV-absorbing bacteria from the mucus of the corals Porites lutea and Acropora hyacinthus during the pre-summer and summer seasons. A total of 17 UV-absorbing bacteria were isolated and sequenced. The UV-absorbing bacteria showed UV absorption at wavelengths ranging from λ max = 333 nm to λ min = 208 nm. Analysis of the DNA sequences revealed that the majority of the UV-absorbing bacteria belonged to the family Firmicutes and the remaining belonged to the family Proteobacteria (class Gammaproteobacteria). Comparison of the sequences with the curated database yielded four distinct bacterial groups belonging to the genus Bacillus, Staphylococcus, Salinicoccus and Vibrio. The absorption peaks for the UV-absorbing bacteria shifted to the UV-A range (320-400 nm) when they were incubated at higher temperatures. Deciphering the complex relationship between corals and their associated bacteria will help us to understand their adaptive strategies to various stresses.

Interaction between inorganic nutrients and organic matter in controlling coral reef communities in Glovers Reef Belize.

PubMed

McClanahan, T R; Steneck, R S; Pietri, D; Cokos, B; Jones, S

2005-05-01

We studied the responses of algae, corals, and small fish to elevated inorganic fertilizer, organic matter, and their combination over a 49-day summer period in cages that simulated the coral reef in the remote Glovers reef atoll, Belize. The addition of organic matter reduced while fertilization had no effect on the numbers of herbivorous damsel and parrotfishes. All measures of algal biomass were influenced by fertilization. The combined inorganic and organic enrichment produced the highest algal biomass, which is most likely due to the combined effect of higher nutrients and lower herbivory. The cover of turf and total algae were influenced by all treatments and their interactions and most strongly and positively influenced by fertilization followed by organic matter and the combination of organic matter and inorganic fertilizer. The inorganic and combined treatments were both dominated by two turf algae, Enteromorpha prolifera and Digenia simplex, while the nonfertilized treatments were dominated by brown frondose algae Lobophora variegata, Padina sanctae, and Dictyota cervicornis. The organic matter treatment had greater cover of P. sanctae and D. cervicornis than the untreated control, which was dominated by Lobophora variegata, also the dominant algae on the nearby patch reefs. Crustose corallines grew slowly ( approximately 2.5 mm/49 days) and were not influenced by the treatments when grown on vertical surfaces but decreased on horizontal coral plates in the combined organic matter and fertilization treatment. No mortality occurred for the two coral species that were added to the cages. Porites furcata darkened in the fertilized cages while there was a mix of paling and darkening for a small amount of the coral tissue of Diploria labyrinthiformes. Inorganic fertilization stimulates small filamentous turf algae and Symbiodinium living in coral but inhibits brown frondose algae. Organic matter inhibits small herbivorous fish, L. variegata, and encrusting

Semi-permeable species boundaries in the coral genus Madracis: introgression in a brooding coral system.

PubMed

Frade, P R; Reyes-Nivia, M C; Faria, J; Kaandorp, J A; Luttikhuizen, P C; Bak, R P M

2010-12-01

Introgressive hybridization is described in several phylogenetic studies of mass-spawning corals. However, the prevalence of this process among brooding coral species is unclear. We used a mitochondrial (mtDNA: nad5) and two nuclear (nDNA: ATPSα and SRP54) intron markers to explore species barriers in the coral genus Madracis and address the role of hybridization in brooding systems. Specimens of six Caribbean Madracis morphospecies were collected from 5 to 60 m depth at Buoy One, Curaçao, supplemented by samples from Aruba, Trinidad & Tobago and Bermuda. Polymerase chain reaction and denaturing gradient gel electrophoresis were coupled to detect distinct alleles within single colonies. The recurrent nDNA phylogenetic non-monophyly among taxa is only challenged by Madracis senaria, the single monophyletic species within the genus. nDNA AMOVAs indicated overall statistical divergence (0.1% significance level) among species but pairwise comparisons of genetic differentiation revealed some gene exchange between Madracis taxa. mtDNA sequences clustered in two main groups representing typical shallow and deep water Madracis species. Madracis pharensis shallow and deep colonies (with threshold at about 23-24 m) clustered in different mtDNA branches, together with their depth-sympatric congenerics. This divergence was repeated for the nDNA (ATPSα) suggestive of distinct M. pharensis depth populations. These matched the vertical distribution of the dinoflagellate symbionts hosted by M. pharensis, with Symbiodinium ITS2 type B7 in the shallows but type B15 in the deep habitats, suggesting symbiont-related disruptive selection. Recurrent non-monophyly of Madracis taxa and high levels of shared polymorphism reflected in ambiguous phylogenetic networks indicate that hybridization is likely to have played a role in the evolution of the genus. Using coalescent forward-in-time simulations, lineage sorting alone was rejected as an explanation to the SRP54 genetic variation

Mine waste disposal leads to lower coral cover, reduced species richness and a predominance of simple coral growth forms on a fringing coral reef in Papua New Guinea.

PubMed

Haywood, M D E; Dennis, D; Thomson, D P; Pillans, R D

2016-04-01

A large gold mine has been operating at the Lihir Island Group, Papua New Guinea since 1997. The mine disposes of waste rock in nearshore waters, impacting nearby coral communities. During 2010, 2012 we conducted photographic surveys at 73 sites within 40 km of the mine to document impacts of mining operations on the hard coral communities. Coral communities close to the mine (∼2 km to the north and south of the mine) were depaurperate, but surprisingly, coral cover and community composition beyond this range appeared to be relatively similar, suggesting that the mine impacts were limited spatially. In particular, we found mining operations have resulted in a significant decrease in coral cover (4.4% 1.48 km from the disposal site c.f. 66.9% 10.36 km from the disposal site), decreased species richness and a predominance of less complex growth forms within ∼2 km to the north and south of the mine waste disposal site. In contrast to the two 'snapshot' surveys of corals performed in 2010 and 2012, long term data (1999-2012) based on visual estimates of coral cover suggested that impacts on coral communities may have been more extensive than this. With global pressures on the world's coral reefs increasing, it is vital that local, direct anthropogenic pressures are reduced, in order to help offset the impacts of climate change, disease and predation. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Seasonal Preservation Success of the Marine Dinoflagellate Coral Symbiont, Symbiodinium sp.

PubMed Central

Hagedorn, Mary; Carter, Virginia L.

2015-01-01

Coral reefs are some of the most diverse and productive ecosystems on the planet, but are threatened by global and local stressors, mandating the need for incorporating ex situ conservation practices. One approach that is highly protective is the development of genome resource banks that preserve the species and its genetic diversity. A critical component of the reef are the endosymbiotic algae, Symbiodinium sp., living within most coral that transfer energy-rich sugars to their hosts. Although Symbiodinium are maintained alive in culture collections around the world, the cryopreservation of these algae to prevent loss and genetic drift is not well-defined. This study examined the quantum yield physiology and freezing protocols that resulted in survival of Symbiodinium at 24 h post-thawing. Only the ultra-rapid procedure called vitrification resulted in success whereas conventional slow freezing protocols did not. We determined that success also depended on using a thin film of agar with embedded Symbiodinium on Cryotops, a process that yielded a post-thaw viability of >50% in extracted and vitrified Symbiodinium from Fungia scutaria, Pocillopora damicornis and Porites compressa. Additionally, there also was a seasonal influence on vitrification success as the best post-thaw survival of F. scutaria occurred in winter and spring compared to summer and fall (P < 0.05). These findings lay the foundation for developing a viable genome resource bank for the world’s Symbiodinium that, in turn, will not only protect this critical element of coral functionality but serve as a resource for understanding the complexities of symbiosis, support selective breeding experiments to develop more thermally resilient strains of coral, and provide a ‘gold-standard’ genomics collection, allowing for full genomic sequencing of unique Symbiodinium strains. PMID:26422237

Spatial variation in abundance, size and orientation of juvenile corals related to the biomass of parrotfishes on the Great Barrier Reef, Australia.

PubMed

Trapon, Melanie L; Pratchett, Morgan S; Hoey, Andrew S

2013-01-01

For species with complex life histories such as scleractinian corals, processes occurring early in life can greatly influence the number of individuals entering the adult population. A plethora of studies have examined settlement patterns of coral larvae, mostly on artificial substrata, and the composition of adult corals across multiple spatial and temporal scales. However, relatively few studies have examined the spatial distribution of small (≤50 mm diameter) sexually immature corals on natural reef substrata. We, therefore, quantified the variation in the abundance, composition and size of juvenile corals (≤50 mm diameter) among 27 sites, nine reefs, and three latitudes spanning over 1000 km on Australia's Great Barrier Reef. Overall, 2801 juveniles were recorded with a mean density of 6.9 (±0.3 SE) ind.m(-2), with Acropora, Pocillopora, and Porites accounting for 84.1% of all juvenile corals surveyed. Size-class structure, orientation on the substrate and taxonomic composition of juvenile corals varied significantly among latitudinal sectors. The abundance of juvenile corals varied both within (6-13 ind.m(-2)) and among reefs (2.8-11.1 ind.m(-2)) but was fairly similar among latitudes (6.1-8.2 ind.m(-2)), despite marked latitudinal variation in larval supply and settlement rates previously found at this scale. Furthermore, the density of juvenile corals was negatively correlated with the biomass of scraping and excavating parrotfishes across all sites, revealing a potentially important role of parrotfishes in determining distribution patterns of juvenile corals on the Great Barrier Reef. While numerous studies have advocated the importance of parrotfishes for clearing space on the substrate to facilitate coral settlement, our results suggest that at high biomass they may have a detrimental effect on juvenile coral assemblages. There is, however, a clear need to directly quantify rates of mortality and growth of juvenile corals to understand the relative

Coral calcification in a changing World and the interactive dynamics of pH and DIC upregulation.

PubMed

McCulloch, Malcolm T; D'Olivo, Juan Pablo; Falter, James; Holcomb, Michael; Trotter, Julie A

2017-05-30

Coral calcification is dependent on the mutualistic partnership between endosymbiotic zooxanthellae and the coral host. Here, using newly developed geochemical proxies (δ 11 B and B/Ca), we show that Porites corals from natural reef environments exhibit a close (r 2 ∼0.9) antithetic relationship between dissolved inorganic carbon (DIC) and pH of the corals' calcifying fluid (cf). The highest DIC cf (∼ × 3.2 seawater) is found during summer, consistent with thermal/light enhancement of metabolically (zooxanthellae) derived carbon, while the highest pH cf (∼8.5) occurs in winter during periods of low DIC cf (∼ × 2 seawater). These opposing changes in DIC cf and pH cf are shown to maintain oversaturated but stable levels of carbonate saturation (Ω cf ∼ × 5 seawater), the key parameter controlling coral calcification. These findings are in marked contrast to artificial experiments and show that pH cf upregulation occurs largely independent of changes in seawater carbonate chemistry, and hence ocean acidification, but is highly vulnerable to thermally induced stress from global warming.

Tissue mortality by Caribbean ciliate infection and white band disease in three reef-building coral species

PubMed Central

Bastidas, Carolina; Croquer, Aldo

2016-01-01

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms: Orbicella faveolata (massive-boulder), O. annularis (massive-columnar) and Acropora cervicornis (branching). We also compared mortality rates in colonies of A. cervicornis bearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. In A. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI in A. cervicornis was faster than in the massive species O. faveolata (0.5 ± 0.6 mm/day) and O. annularis (0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the mortality rates for both diseases regardless of coral species. This is the first study providing coral tissue mortality and regeneration rates associated to CCI in colonies with massive morphologies, and it highlights the risks of further cover losses of the three most important reef-building species in the Caribbean. PMID:27547525

Modeling fine-scale coral larval dispersal and interisland connectivity to help designate mutually-supporting coral reef marine protected areas: Insights from Maui Nui, Hawaii

USGS Publications Warehouse

Storlazzi, Curt; van Ormondt, Maarten; Chen, Yi-Leng; Elias, Edwin P. L.

2017-01-01

Connectivity among individual marine protected areas (MPAs) is one of the most important considerations in the design of integrated MPA networks. To provide such information for managers in Hawaii, USA, a numerical circulation model was developed to determine the role of ocean currents in transporting coral larvae from natal reefs throughout the high volcanic islands of the Maui Nui island complex in the southeastern Hawaiian Archipelago. Spatially- and temporally-varying wind, wave, and circulation model outputs were used to drive a km-scale, 3-dimensional, physics-based circulation model for Maui Nui. The model was calibrated and validated using satellite-tracked ocean surface current drifters deployed during coral-spawning conditions, then used to simulate the movement of the larvae of the dominant reef-building coral, Porites compressa, from 17 reefs during eight spawning events in 2010–2013. These simulations make it possible to investigate not only the general dispersal patterns from individual coral reefs, but also how anomalous conditions during individual spawning events can result in large deviations from those general patterns. These data also help identify those reefs that are dominated by self-seeding and those where self-seeding is limited to determine their relative susceptibility to stressors and potential roadblocks to recovery. Overall, the numerical model results indicate that many of the coral reefs in Maui Nui seed reefs on adjacent islands, demonstrating the interconnected nature of the coral reefs in Maui Nui and providing a key component of the scientific underpinning essential for the design of a mutually supportive network of MPAs to enhance conservation of coral reefs.

Evaluating the Influence of Solar Radiation, Coral Extension Rate and Anthropogenic CO2 on Skeletal δ13C in a Network of Fiji and Tonga Porites Corals

NASA Astrophysics Data System (ADS)

Dassie, E. P.; Lemley, G. M.; Linsley, B. K.; Howe, S. S.

2011-12-01

While stable oxygen isotope signatures in coral reefs have proven to be reliable recorders of temperature and salinity, it is difficult to interpret their skeletal 13C/12C signatures. Various studies have suggested that coral skeletal δ13C is primarily controlled by complex physiological mechanisms. However, it has also been proposed that δ13C variations in coral skeletons are related to more apparent factors such as solar radiation, skeletal extension rate, and the anthropogenic addition of 13C-depleted CO2 into the atmosphere and surface ocean ("Suess Effect"). We will present time-series variations of δ13C in six coral cores from Fiji and Tonga (South Pacific Ocean). On seasonal timescales, increases in solar radiation are correlated to increases in skeletal δ13C and visa-versa. Annually averaged data shows a correlation between increased coral δ13C and reduced coral extension rate, while a decrease in δ13C is associated with an increased extension rate. In the most recent portion of four of the coral δ13C records (from around 1900 to the core top), the value progressively decreases - a trend that is not present in either the skeletal extension rate or solar radiation data. We conclude that this decreasing δ13C trend is a consequence of the Suess Effect, as reported in other coral δ13C records. However, two of the six corals do not show this decreasing trend, which may be a result of their residence in especially shallow water (sub-tidal environments). The onset of the Suess effect in the four corals may help constrain the timing of the uptake of anthropogenic carbon by the western South Pacific Ocean. Although all factors controlling δ13C variation in corals are not completely understood, this study works towards an understanding of their relative contribution to δ13C variation.

Ecological Risk Assessment of Munitions Compounds on Coral and Coral Reef Health

DTIC Science & Technology

2014-01-01

C308R Porites lobata Maunalua Bay, Oahu, HI K5 TAG GTG GGG AAT CAA ACG GC C307F C309F Porites lobata La Perouse, Maui, HI 3-3 GCT GGC TTA CAG...GGA ATT TTA ACT TCA AGC 24 41.7% 54°C 2.08 Kb this work Porites mtDNA cobR A GAT TCT CTT TGC GCA GTG GCA TAG G 25 52.0% 59°C this work Porites mtDNA...47.6% 52°C 2.14 Kb this work Porites mtDNA nad5(5’)R K CCA ACT GTG CAG ACT TTC CAA CC 23 52.2% 57°C this work References and further reading

Effects of acidified seawater on coral calcification and variations of U/Ca ratio in their skeletons

NASA Astrophysics Data System (ADS)

Inoue, M.; Ozaki, S.; Iguchi, A.; Sakai, K.; Suzuki, A.; Kawahata, H.

2011-12-01

The rising CO2 concentration in the atmosphere is changing the carbonate chemistry of the ocean. Elevated partial pressure of CO2 (pCO2) has caused significant decrease in surface seawater pH and carbonate ion concentration. Therefore, ocean acidification has a negative effect on calcification of marine calcifying organisms. Especially, hermatypic corals are dominant organisms in coral reef ecosystems, so their calcificication is a key to determine the health of reef ecosystems. On the other hand, recent study has suggested that there is a negative correlation between U/Ca ratio in coral skeleton and seawater pH, based on the culture experiment using primary polyps of Acropora digitifera. In this study, primary polyps and adult colonies of A. digitifera and adult colonies of Porites australiensis, which are the dominant species around the Ryukyu Islands, Japan, were reared in seawater with different pCO2 (300, 400, 600, 800, 1000ppm) and pH (7.4, 7.6, 8.0) settings controlled by CO2 bubbling. Calcification rate of adult coral was estimated by buoyant method, while skeletal growth of polyps was evaluated by measuring the dry weight of each skeleton after the experiments. In order to evaluate the relationship between U/Ca ratios in coral skeletons and seawater pH, U/Ca ratios in reared corals were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results of A. digitifera showed that the growth rate of adult corals had no significant correlation against pCO2, but dry weight of polyp skeletons decreased with increase in pCO2. Growth rate of P. australiensis typically showed a positive correlation with pH. However, growth rates were different among colonies, suggesting that their responses to acidification may vary among the colonies. Regarding the variations of U/Ca ratios, there were positive correlations between U/Ca ratios in adults of A. digitifera and P. australiensis and seawater pCO2 (pH), while no relation was observed in polyp corals.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998

NASA Astrophysics Data System (ADS)

Pisapia, C.; Burn, D.; Yoosuf, R.; Najeeb, A.; Anderson, K. D.; Pratchett, M. S.

2016-10-01

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998.

PubMed

Pisapia, C; Burn, D; Yoosuf, R; Najeeb, A; Anderson, K D; Pratchett, M S

2016-10-03

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience.

Coral recovery in the central Maldives archipelago since the last major mass-bleaching, in 1998

PubMed Central

Pisapia, C.; Burn, D.; Yoosuf, R.; Najeeb, A.; Anderson, K. D.; Pratchett, M. S.

2016-01-01

Increasing frequency and severity of disturbances is causing global degradation of coral reef ecosystems. This study examined temporal changes in live coral cover and coral composition in the central Maldives from 1997 to 2016, encompassing two bleaching events, a tsunami, and an outbreak of Acanthaster planci. We also examined the contemporary size structure for five dominant coral taxa (tabular Acropora, Acropora muricata, Acropora humilis, Pocillopora spp, and massive Porites). Total coral cover increased throughout the study period, with marked increases following the 1998 mass-bleaching. The relative abundance of key genera has changed through time, where Acropora and Pocillopora (which are highly susceptible to bleaching) were under-represented following 1998 mass-bleaching but increased until outbreaks of A. planci in 2015. The contemporary size-structure for all coral taxa was dominated by larger colonies with peaked distributions suggesting that recent disturbances had a disproportionate impact on smaller colonies, or that recruitment is currently limited. This may suggest that coral resilience has been compromised by recent disturbances, and further bleaching (expected in 2016) could lead to highly protracted recovery times. We showed that Maldivian reefs recovered following the 1998 mass-bleaching event, but it took up to a decade, and ongoing disturbances may be eroding reef resilience. PMID:27694823

Climate-driven coral reorganisation influences aggressive behaviour in juvenile coral-reef fishes

NASA Astrophysics Data System (ADS)

Kok, Judith E.; Graham, Nicholas A. J.; Hoogenboom, Mia O.

2016-06-01

Globally, habitat degradation is altering the abundance and diversity of species in a variety of ecosystems. This study aimed to determine how habitat degradation, in terms of changing coral composition under climate change, affected abundance, species richness and aggressive behaviour of juveniles of three damselfishes ( Pomacentrus moluccensis, P. amboinensis and Dischistodus perspicillatus, in order of decreasing reliance on coral). Patch reefs were constructed to simulate two types of reefs: present-day reefs that are vulnerable to climate-induced coral bleaching, and reefs with more bleaching-robust coral taxa, thereby simulating the likely future of coral reefs under a warming climate. Fish communities were allowed to establish naturally on the reefs during the summer recruitment period. Climate-robust reefs had lower total species richness of coral-reef fishes than climate-vulnerable reefs, but total fish abundance was not significantly different between reef types (pooled across all species and life-history stages). The nature of aggressive interactions, measured as the number of aggressive chases, varied according to coral composition; on climate-robust reefs, juveniles used the substratum less often to avoid aggression from competitors, and interspecific aggression became relatively more frequent than intraspecific aggression for juveniles of the coral-obligate P. moluccensis. This study highlights the importance of coral composition as a determinant of behaviour and diversity of coral-reef fishes.

Metal concentrations in the growth bands of Porites sp.: A baseline record on the history of marine pollution in the Gulf of Mannar, India.

PubMed

Krishnakumar, S; Ramasamy, S; Magesh, N S; Chandrasekar, N; Simon Peter, T

2015-12-15

The present study was carried out on the Porites coral growth bands (1979 to 2014) to measure the metal accumulation for assessing the environmental pollution status. The concentrations of studied metals are compared with similar global studies, which indicate that the metals are probably derived from natural sources. The identical peaks of Fe and Mn are perfectly matched with Cu, Cr and Ni concentrations. However, the metal profile trend is slightly depressed from a regular trend in Zn, Cd and Pb peaks. The metal accumulation affinity of the reef skeleton is ranked in the following order Cr>Cd>Pb>Fe>Mn>Cu>Ni>Zn. The distribution of metal constituents in coral growth bands is primarily controlled by Fe and Mn in the reef skeleton. Other reef associated metals such as Pb and Cd are derived from other sources like coastal developments and anthropogenic sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

Phage and Nucleocytoplasmic Large Viral Sequences Dominate Coral Viromes from the Arabian Gulf.

PubMed

Mahmoud, Huda; Jose, Liny

2017-01-01

Corals that naturally thrive under extreme conditions are gaining increasing attention due to their importance as living models to understand the impact of global warming on world corals. Here, we present the first metagenomic study of viral communities in corals thriving in a thermally variable water body in which the temperature fluctuates between 11 and 39°C in different seasons. The viral assemblages of two of the most abundant massive ( Porites harrisoni ) and branching ( Acropora downingi ) corals in offshore and inshore reef systems in the northern Arabian Gulf were investigated. Samples were collected from five reef systems during summer, autumn and winter of 2011/2012. The two coral viromes contain 12 viral families, including 10 dsDNA viral families [Siphoviridae, Podoviridae, Myoviridae, Phycodnaviridae, Baculoviridae, Herpesviridae, Adenoviridae, Alloherpesviridae, Mimiviridae and one unclassified family], one-ssDNA viral family (Microviridae) and one RNA viral family (Retroviridae). Overall, sequences significantly similar to Podoviridae were the most abundant in the P. harrisoni and A. downingi viromes. Various morphological types of virus-like particles (VLPs) were confirmed in the healthy coral tissue by transmission electron microscopy, including large tailless VLPs and electron-dense core VLPs. Tailed bacteriophages were isolated from coral tissue using a plaque assay. Higher functional gene diversity was recorded in A. downingi than in P. harrisoni , and comparative metagenomics revealed that the Gulf viral assemblages are functionally distinct from Pacific Ocean coral viral communities.

First report of bioaccumulation and bioconcentration of aliphatic hydrocarbons (AHs) and persistent organic pollutants (PAHs, PCBs and PCNs) and their effects on alcyonacea and scleractinian corals and their endosymbiotic algae from the Persian Gulf, Iran: Inter and intra-species differences.

PubMed

Ranjbar Jafarabadi, Ali; Riyahi Bakhtiari, Alireza; Aliabadian, Mansour; Laetitia, Hédouin; Shadmehri Toosi, Amirhossein; Yap, Chee Kong

2018-06-15

The coral reefs of the Persian Gulf are the most diverse systems of life in the marine environment of the Middle East. Unfortunately, they are highly threatened by local and global stressors, particularly oil pollutants. This is the first quantitative and qualitative study aimed at assessing the concentration and sources of n-alkanes and POPs (PAHs, PCBs and PCNs) in coral tissues, symbiotic algae (zooxanthellae), reef sediments and seawaters in coral reefs of Lark and Kharg in the Persian Gulf, Iran. This work was conducted on eight species of six genera and three families of hard corals and one family of soft coral. A significant variation in the concentration of ∑30n-alkanes and POPs (∑40PAHs, ∑22PCBs and 20PCNs) was found in the decreasing order: zooxanthellae > coral tissue > skeleton > reef sediment > seawater. The bioaccumulation of these compounds was 2-times higher in ahermatypic than in hermatypic corals, among which significant variations were observed in both sites. In Kharg, Porites lutea had the highest mean concentration of ∑30n-alkanes and ∑40PAHs in soft tissue, whereas the lowest values were in Platygyra daedalea. A contrasting trend was documented for ∑22PCBs and 20PCNs, with the highest level reported in soft tissue of P. daedalea and the lowest in P. lutea at Kharg. Compositional pattern of AHs and PAHs demonstrated the predominance of LMW-PAHs and n-alkanes. In skeleton and reef sediments, tetra, penta and tri-CBs were the most abundant PCBs congeners followed by di-CB > hexa-CB > hepta-CB > octa-CB,whiletri-CB > di-CB > tetra-CB > penta-CB > hexa-CB > hepta-CB > octa-CB was observed for soft tissue, zooxanthellae and seawater. The results of RAD test indicated significantly negative correlation between total concentration of these compounds with zooxanthellae density, the chlorophyll-a and C 2 in corals at both reefs. This is the first report on levels, health assessment and

Colony-specific investigations reveal highly variable responses among individual corals to ocean acidification and warming.

PubMed

Kavousi, Javid; Reimer, James Davis; Tanaka, Yasuaki; Nakamura, Takashi

2015-08-01

As anthropogenic climate change is an ongoing concern, scientific investigations on its impacts on coral reefs are increasing. Although impacts of combined ocean acidification (OA) and temperature stress (T) on reef-building scleractinian corals have been studied at the genus, species and population levels, there are little data available on how individual corals respond to combined OA and anomalous temperatures. In this study, we exposed individual colonies of Acropora digitifera, Montipora digitata and Porites cylindrica to four pCO2-temperature treatments including 400 μatm-28 °C, 400 μatm-31 °C, 1000 μatm-28 °C and 1000 μatm-31 °C for 26 days. Physiological parameters including calcification, protein content, maximum photosynthetic efficiency, Symbiodinium density, and chlorophyll content along with Symbiodinium type of each colony were examined. Along with intercolonial responses, responses of individual colonies versus pooled data to the treatments were investigated. The main results were: 1) responses to either OA or T or their combination were different between individual colonies when considering physiological functions; 2) tolerance to either OA or T was not synonymous with tolerance to the other parameter; 3) tolerance to both OA and T did not necessarily lead to tolerance of OA and T combined (OAT) at the same time; 4) OAT had negative, positive or no impacts on physiological functions of coral colonies; and 5) pooled data were not representative of responses of all individual colonies. Indeed, the pooled data obscured actual responses of individual colonies or presented a response that was not observed in any individual. From the results of this study we recommend improving experimental designs of studies investigating physiological responses of corals to climate change by complementing them with colony-specific examinations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coral diseases and bleaching on Colombian Caribbean coral reefs.

PubMed

Navas-Camacho, Raúl; Gil-Agudelo, Diego Luis; Rodríguez-Ramírez, Alberto; Reyes-Nivia, María Catalina; Garzón-Ferreira, Jaime

2010-05-01

Since 1998 the National Monitoring System for the Coral Reefs of Colombia (SIMAC) has monitored the occurrence of coral bleaching and diseases in some Colombian coral reefs (permanent stations at San Andres Island, Rosario Islands, Tayrona, San Bernardo Islands and Urabá). The main purpose is to evaluate their health status and to understand the factors that have been contributing to their decline. To estimate these occurrences, annual surveys in 126 permanent belt transects (10 x 2m) with different depth intervals (3-6 meters, 9-12 meters and 15-18 meters) are performed at all reef sites. Data from the 1998-2004 period, revealed that San Andrés Island had many colonies with diseases (38.9 colonies/m2), and Urabá had high numbers with bleaching (54.4 colonies/m2). Of the seven reported coral diseases studied, Dark Spots Disease (DSD), and White Plague Disease (WPD) were noteworthy because they occurred in all Caribbean monitored sites, and because of their high interannual infection incidence. Thirty five species of scleractinian corals were affected by at least one disease and a high incidence of coral diseases on the main reef builders is documented. Bleaching was present in 34 species. During the whole monitoring period, Agaricia agaricites and Siderastrea siderea were the species most severely affected by DSD and bleaching, respectively. Diseases on species such as Agaricia fragilis, A. grahamae, A. humilis, Diploria clivosa, Eusmilia fastigiata, Millepora complanata, and Mycetophyllia aliciae are recorded for first time in Colombia. We present bleaching and disease incidences, kinds of diseases, coral species affected, reef localities studied, depth intervals of surveys, and temporal (years) variation for each geographic area. This variation makes difficult to clearly determine defined patterns or general trends for monitored reefs. This is the first long-term study of coral diseases and bleaching in the Southwestern Caribbean, and one of the few long

Incorporating climate and ocean change into extinction risk assessments for 82 coral species.

PubMed

Brainard, Russell E; Weijerman, Mariska; Eakin, C Mark; McElhany, Paul; Miller, Margaret W; Patterson, Matt; Piniak, Gregory A; Dunlap, Matthew J; Birkeland, Charles

2013-12-01

Many marine invertebrate species facing potential extinction have uncertain taxonomies and poorly known demographic and ecological traits. Uncertainties are compounded when potential extinction drivers are climate and ocean changes whose effects on even widespread and abundant species are only partially understood. The U.S. Endangered Species Act mandates conservation management decisions founded on the extinction risk to species based on the best available science at the time of consideration-requiring prompt action rather than awaiting better information. We developed an expert-opinion threat-based approach that entails a structured voting system to assess extinction risk from climate and ocean changes and other threats to 82 coral species for which population status and threat response information was limited. Such methods are urgently needed because constrained budgets and manpower will continue to hinder the availability of desired data for many potentially vulnerable marine species. Significant species-specific information gaps and uncertainties precluded quantitative assessments of habitat loss or population declines and necessitated increased reliance on demographic characteristics and threat vulnerabilities at genus or family levels. Adapting some methods (e.g., a structured voting system) used during other assessments and developing some new approaches (e.g., integrated assessment of threats and demographic characteristics), we rated the importance of threats contributing to coral extinction risk and assessed those threats against population status and trend information to evaluate each species' extinction risk over the 21st century. This qualitative assessment resulted in a ranking with an uncertainty range for each species according to their estimated likelihood of extinction. We offer guidance on approaches for future biological extinction risk assessments, especially in cases of data-limited species likely to be affected by global-scale threats

First characterization of bacterial pathogen, Vibrio alginolyticus, for Porites andrewsi White syndrome in the South China Sea.

PubMed

Zhenyu, Xie; Shaowen, Ke; Chaoqun, Hu; Zhixiong, Zhu; Shifeng, Wang; Yongcan, Zhou

2013-01-01

White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown. A transmission experiment was performed on P. andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm(2) d(-1) with a mean of 5.40 ± 3.34 cm(2) d(-1) (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch's postulates for establishing causality. Following exposure to bacterial concentrations of 10(5) cells mL(-1), the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus . This is the first report of V. alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V. alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea.

First Characterization of Bacterial Pathogen, Vibrio alginolyticus, for Porites andrewsi White Syndrome in the South China Sea

PubMed Central

Chaoqun, Hu; Zhixiong, Zhu; Shifeng, Wang; Yongcan, Zhou

2013-01-01

Background White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown. Methodology/Principal Findings A transmission experiment was performed on P . andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm2 d-1 with a mean of 5.40 ± 3.34 cm2 d-1 (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch’s postulates for establishing causality. Following exposure to bacterial concentrations of 105 cells mL-1, the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus . Conclusion/Significance This is the first report of V . alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V . alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea. PMID:24086529

Impacts of turbidity on corals: The relative importance of light limitation and suspended sediments.

PubMed

Bessell-Browne, Pia; Negri, Andrew P; Fisher, Rebecca; Clode, Peta L; Duckworth, Alan; Jones, Ross

2017-04-15

As part of an investigation of the effects of water quality from dredging/natural resuspension on reefs, the effects of suspended sediment concentrations (SSCs) (0, 30, 100mgL -1 ) and light (~0, 1.1, 8.6molphotonsm -2 d -1 ) were examined alone and in combination, on the corals Acropora millepora, Montipora capricornis and Porites spp. over an extended (28d) period. No effects were observed at any sediment concentrations when applied alone. All corals in the lowest light treatments lost chlorophyll a and discoloured (bleached) after a week. Coral mortality only occurred in the two lowest light treatments and was higher when simultaneously exposed to elevated SSCs. Compared to water quality data collected during large dredging programs and natural resuspension events (and in the absence of sediment deposition as a cause-effect pathway) these data suggest the light reduction associated with turbidity poses a proportionally greater risk than effects of elevated SSCs alone. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brucite microbialites in living coral skeletons: Indicators of extreme microenvironments in shallow-marine settings

USGS Publications Warehouse

Nothdurft, L.D.; Webb, G.E.; Buster, N.A.; Holmes, C.W.; Sorauf, J.E.; Kloprogge, J.T.

2005-01-01

Brucite [Mg(OH)2] microbialites occur in vacated interseptal spaces of living scleractinian coral colonies (Acropora, Pocillopora, Porites) from subtidal and intertidal settings in the Great Barrier Reef, Australia, and subtidal Montastraea from the Florida Keys, United States. Brucite encrusts microbial filaments of endobionts (i.e., fungi, green algae, cyanobacteria) growing under organic biofilms; the brucite distribution is patchy both within interseptal spaces and within coralla. Although brucite is undersaturated in seawater, its precipitation was apparently induced in the corals by lowered pCO 2 and increased pH within microenvironments protected by microbial biofilms. The occurrence of brucite in shallow-marine settings highlights the importance of microenvironments in the formation and early diagenesis of marine carbonates. Significantly, the brucite precipitates discovered in microenvironments in these corals show that early diagenetic products do not necessarily reflect ambient seawater chemistry. Errors in environmental interpretation may arise where unidentified precipitates occur in microenvironments in skeletal carbonates that are subsequently utilized as geochemical seawater proxies. ?? 2005 Geological Society of America.

A Fiji multi-coral δ18O composite approach to obtaining a more accurate reconstruction of the last two-centuries of the ocean-climate variability in the South Pacific Convergence Zone region

NASA Astrophysics Data System (ADS)

Dassié, Emilie P.; Linsley, Braddock K.; Corrège, Thierry; Wu, Henry C.; Lemley, Gavin M.; Howe, Steve; Cabioch, Guy

2014-12-01

The limited availability of oceanographic data in the tropical Pacific Ocean prior to the satellite era makes coral-based climate reconstructions a key tool for extending the instrumental record back in time, thereby providing a much needed test for climate models and projections. We have generated a unique regional network consisting of five Porites coral δ18O time series from different locations in the Fijian archipelago. Our results indicate that using a minimum of three Porites coral δ18O records from Fiji is statistically sufficient to obtain a reliable signal for climate reconstruction, and that application of an approach used in tree ring studies is a suitable tool to determine this number. The coral δ18O composite indicates that while sea surface temperature (SST) variability is the primary driver of seasonal δ18O variability in these Fiji corals, annual average coral δ18O is more closely correlated to sea surface salinity (SSS) as previously reported. Our results highlight the importance of water mass advection in controlling Fiji coral δ18O and salinity variability at interannual and decadal time scales despite being located in the heavy rainfall region of the South Pacific Convergence Zone (SPCZ). The Fiji δ18O composite presents a secular freshening and warming trend since the 1850s coupled with changes in both interannual (IA) and decadal/interdecadal (D/I) variance. The changes in IA and D/I variance suggest a re-organization of climatic variability in the SPCZ region beginning in the late 1800s to period of a more dominant interannual variability, which could correspond to a southeast expansion of the SPCZ.

Large predatory coral trout species unlikely to meet increasing energetic demands in a warming ocean.

PubMed

Johansen, J L; Pratchett, M S; Messmer, V; Coker, D J; Tobin, A J; Hoey, A S

2015-09-08

Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important coral reef fishery species in the Indo-west Pacific, the large predatory coral trout Plectropomus leopardus (Serranidae), can behaviourally adjust food intake to maintain body-condition under elevated temperatures, and acclimate over time to consume larger meals. However, these increased energetic demands are unlikely to be met by adequate production at lower trophic levels, as smaller prey species are often the first to decline in response to climate-induced loss of live coral and structural complexity. Consequently, ubiquitous increases in energy consumption due to climate change will increase top-down competition for a dwindling biomass of prey, potentially distorting entire food webs and associated fisheries.

Large predatory coral trout species unlikely to meet increasing energetic demands in a warming ocean

PubMed Central

Johansen, J.L.; Pratchett, M.S.; Messmer, V.; Coker, D.J.; Tobin, A.J.; Hoey, A.S.

2015-01-01

Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important coral reef fishery species in the Indo-west Pacific, the large predatory coral trout Plectropomus leopardus (Serranidae), can behaviourally adjust food intake to maintain body-condition under elevated temperatures, and acclimate over time to consume larger meals. However, these increased energetic demands are unlikely to be met by adequate production at lower trophic levels, as smaller prey species are often the first to decline in response to climate-induced loss of live coral and structural complexity. Consequently, ubiquitous increases in energy consumption due to climate change will increase top-down competition for a dwindling biomass of prey, potentially distorting entire food webs and associated fisheries. PMID:26345733

Resilience of coral-associated bacterial communities exposed to fish farm effluent.

PubMed

Garren, Melissa; Raymundo, Laurie; Guest, James; Harvell, C Drew; Azam, Farooq

2009-10-06

The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution. We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments) were followed for 22 days across five sites: a well-flushed reference site (the original fragment source); two sites with low exposure to milkfish (Chanos chanos) aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC), chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP) abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio) without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels. This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to eutrophication pressure. These data highlight a need for

Resilience of Coral-Associated Bacterial Communities Exposed to Fish Farm Effluent

PubMed Central

Garren, Melissa; Raymundo, Laurie; Guest, James; Harvell, C. Drew; Azam, Farooq

2009-01-01

Background The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution. Methodology & Principal Findings We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments) were followed for 22 days across five sites: a well-flushed reference site (the original fragment source); two sites with low exposure to milkfish (Chanos chanos) aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC), chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP) abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio) without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels. Significance This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to

Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance

PubMed Central

Bromhall, Katrina; Motti, Cherie A.; Munn, Colin B.; Bourne, David G.

2016-01-01

ABSTRACT Pervasive environmental stressors on coral reefs are attributed with shifting the competitive balance in favor of alternative dominants, such as macroalgae. Previous studies have demonstrated that macroalgae compete with corals via a number of mechanisms, including the production of potent primary and secondary metabolites that can influence coral-associated microbial communities. The present study investigates the effects of the Pacific brown macroalga Lobophora sp. (due to the shifting nature of the Lobophora species complex, it will be referred to here as Lobophora sp.) on coral bacterial isolates, coral larvae, and the microbiome associated with the coral Porites cylindrica. Crude aqueous and organic macroalgal extracts were found to inhibit the growth of coral-associated bacteria. Extracts and fractions were also shown to inhibit coral larval settlement and cause mortality at concentrations lower (<0.3 mg · ml−1) than calculated natural concentrations (4.4 mg · ml−1). Microbial communities associated with coral tissues exposed to aqueous (e.g., hydrophilic) crude extracts demonstrated a significant shift to Vibrio dominance and a loss of sequences related to the putative coral bacterial symbiont, Endozoicomonas sp., based on 16S rRNA amplicon sequencing. This study contributes to growing evidence that macroalgal allelochemicals, dissolved organic material, and native macroalgal microbial assemblages all play a role in shifting the microbial equilibrium of the coral holobiont away from a beneficial state, contributing to a decline in coral fitness and a shift in ecosystem structure. IMPORTANCE Diverse microbial communities associate with coral tissues and mucus, providing important protective and nutritional services, but once disturbed, the microbial equilibrium may shift from a beneficial state to one that is detrimental or pathogenic. Macroalgae (e.g., seaweeds) can physically and chemically interact with corals, causing abrasion, bleaching

Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance.

PubMed

Morrow, Kathleen M; Bromhall, Katrina; Motti, Cherie A; Munn, Colin B; Bourne, David G

2017-01-01

Pervasive environmental stressors on coral reefs are attributed with shifting the competitive balance in favor of alternative dominants, such as macroalgae. Previous studies have demonstrated that macroalgae compete with corals via a number of mechanisms, including the production of potent primary and secondary metabolites that can influence coral-associated microbial communities. The present study investigates the effects of the Pacific brown macroalga Lobophora sp. (due to the shifting nature of the Lobophora species complex, it will be referred to here as Lobophora sp.) on coral bacterial isolates, coral larvae, and the microbiome associated with the coral Porites cylindrica. Crude aqueous and organic macroalgal extracts were found to inhibit the growth of coral-associated bacteria. Extracts and fractions were also shown to inhibit coral larval settlement and cause mortality at concentrations lower (<0.3 mg · ml -1 ) than calculated natural concentrations (4.4 mg · ml -1 ). Microbial communities associated with coral tissues exposed to aqueous (e.g., hydrophilic) crude extracts demonstrated a significant shift to Vibrio dominance and a loss of sequences related to the putative coral bacterial symbiont, Endozoicomonas sp., based on 16S rRNA amplicon sequencing. This study contributes to growing evidence that macroalgal allelochemicals, dissolved organic material, and native macroalgal microbial assemblages all play a role in shifting the microbial equilibrium of the coral holobiont away from a beneficial state, contributing to a decline in coral fitness and a shift in ecosystem structure. Diverse microbial communities associate with coral tissues and mucus, providing important protective and nutritional services, but once disturbed, the microbial equilibrium may shift from a beneficial state to one that is detrimental or pathogenic. Macroalgae (e.g., seaweeds) can physically and chemically interact with corals, causing abrasion, bleaching, and overall stress

Molluscan assemblages on coral reefs and associated hard substrata in the northern Red Sea

NASA Astrophysics Data System (ADS)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

Gross, radiology and ultrasonographic evaluation of coral post-implantation in sheep femur.

PubMed

Fadilah, A; Zuki, A B Z; Loqman, M Y; Zamri-Saad, M; Norimah, Y; Asnah, H

2004-05-01

The study was carried out to evaluate macroscopically the ability of coral to repair a large size bone defect. A total 12 adult, male sheep were used in the study. The large bone defect (2.5cm x 0.5cm x 0.5cm) was created surgically on the left proximal femur and replaced by a block of coral (Porites sp.). Radiographs were obtained immediately after surgery and at 2, 4, 8 and 12 weeks post-implantation. Ultrasonographic examinations were carried out every 2 weeks after implantation up to 12 weeks using ultrasound machine (TOSHIBA Capasee II) connected with 7MHz frequency transducer. The sheep were euthanased at 2, 4, 8, and 12 weeks post-implantation and the bone examined grossly. Both ultrasonographs and radiographs taken at 8 and 12 weeks showed that the implants had been resorbed and left the space that much reduced in size. There was no sign of implant rejection observed in all animals. The results showed that processed coral has potential to become bone substitute for reconstructive bone surgery.

Evidence of sexual dimorphism in skeletal morphology of a gonochoric reef coral

PubMed Central

Paz-García, D. A.; Cabral-Tena, R. A.; Balart, E. F.

2018-01-01

In the emerald coral Porites panamensis, the rates of elongation and calcification of colonies are higher in males than in females, probably because of the higher energetic demands of the latter in order to cope with the development of the large planulae produced throughout the year. This differing energetic demand could also be reflected in the sexual dimorphism of the calyces; hence, to test this hypothesis, 11 morphological traits of the corallite were assessed from 63 colonies that were collected in the southern Gulf of California, Mexico. Three traits showed statistical differences between sexes, enabling accurate distinction of males from females. Our results confirm for the first time the existence of external sexual dimorphism in a reef-building coral, opening the possibility that sex-related morphological differences may occur generally in gonochoric scleractinians. These findings can be very useful for the correct classification and characterization of recent and fossil records, helping to improve the historical and evolutive understanding of reef-building corals facing threats under environmental changes. PMID:29892377

Experimental studies of rapid bioerosion of coral reefs in the Galápagos Islands

NASA Astrophysics Data System (ADS)

Reaka-Kudla, M. L.; Feingold, J. S.; Glynn, W.

1996-06-01

Experimental carbonate blocks of coral skeleton, Porites lobata (PL), and cathedral limestone (LS) were deployed for 14.8 months at shallow (5 6 m) and deep (11 13m) depths on a severely bioeroded coral reef, Champion Island, Galápagos Islands, Ecuador. Sea urchins ( Eucidaris thouarsii) were significantly more abundant at shallow versus deep sites. Porites lobata blocks lost an average of 25.4 kg m-2yr-1 (23.71 m-2yr-1 or 60.5% decrease yr-1). Losses did not vary significantly at depths tested. Internal bioeroders excavated an average of 2.6 kg m-2 yr-1 (2.41 m-2 yr-1 or 0.6% decrease yr-1), while external bioeroders removed an average of 22.8 kg m-2 yr-1). (21.31 m-2 yr-1). or 59.9% decrease yr-1). few encrusting organisms were observed on the PL blocks. Cathedral limestone blocks lost an average of 4.1 kg m-2 yr-1). (1.81 m-2 yr-1). or 4.6% decrease yr-'), also with no relation to depth. Internal bioeroders excavated an average of 0.6 kg m-2 yr-1). (0.31 m-2 yr-1). or 0.7% decrease yr-1). and external bioeroders removed an average of 3.5 kg m-2 yr-1). (1.51 m-2 yr-1). or 3.9% decrease yr-1). from the LS blocks. Most (57.6%) encrustation occurred on the bottom of LS blocks, and there was more accretion on block bottoms in deep (61.4 mg cm-2 yr-1). versus shallow (35.0 mg cm-2 yr-1) sites. External bioerosion reduced the average height of the reef framework by 0.2 cm yr-1). for hard substrata (represented by LS) and 2.3 cm yr-1). for soft substrata (represented by PL). The results of this study suggest that coral reef frameworks in the Galápagos Islands are in serious jeopardy. If rates of coral recruitment do not increase, and if rates of bioerosion do not decline, coral reefs in the Galápagos Islands could be eliminated entirely.

The corallivorous flatworm Amakusaplana acroporae: an invasive species threat to coral reefs?

NASA Astrophysics Data System (ADS)

Hume, Benjamin C. C.; D'Angelo, Cecilia; Cunnington, Anna; Smith, Edward G.; Wiedenmann, Jörg

2014-03-01

Fatal infestations of land-based Acropora cultures with so-called Acropora- eating flatworms (AEFWs) are a global phenomenon. We evaluate the hypothesis that AEFWs represent a risk to coral reefs by studying the biology and the invasive potential of an AEFW strain from the UK. Molecular analyses identified this strain as Amakusaplana acroporae, a new species described from two US aquaria and one natural location in Australia. Our molecular data together with life history strategies described here suggest that this species accounts for most reported cases of AEFW infestations. We show that local parasitic activity impairs the light-acclimation capacity of the whole host colony. A. acroporae acquires excellent camouflage by harbouring photosynthetically competent, host-derived zooxanthellae and pigments of the green-fluorescent protein family. It shows a preference for Acropora valida but accepts a broad host range. Parasite survival in isolation (5-7 d) potentially allows for an invasion when introduced as non-native species in coral reefs.

Effects of predation on diel activity and habitat use of the coral-reef shrimp Cinetorhynchus hendersoni (Rhynchocinetidae)

NASA Astrophysics Data System (ADS)

Ory, Nicolas C.; Dudgeon, David; Duprey, Nicolas; Thiel, Martin

2014-09-01

Nonlethal effects of predators on prey behaviour are still poorly understood, although they may have cascading effects through food webs. Underwater observations and experiments were conducted on a shallow fringing coral reef in Malaysia to examine whether predation risks affect diel activity, habitat use, and survival of the rhynchocinetid shrimp Cinetorhynchus hendersoni. The study site was within a protected area where predatory fish were abundant. Visual surveys and tethering experiments were conducted in April-May 2010 to compare the abundance of shrimps and predatory fishes and the relative predation intensity on shrimps during day and night. Shrimps were not seen during the day but came out of refuges at night, when the risk of being eaten was reduced. Shrimp preferences for substrata of different complexities and types were examined at night when they could be seen on the reef; complex substrata were preferred, while simple substrata were avoided. Shrimps were abundant on high-complexity columnar-foliate Porites rus, but tended to make little use of branching Acropora spp. Subsequent tethering experiments, conducted during daytime in June 2013, compared the relative mortality of shrimps on simple (sand-rubble, massive Porites spp.) and complex ( P. rus, branching Acropora spp.) substrata under different predation risk scenarios (i.e., different tether lengths and exposure durations). The mortality of shrimps with short tethers (high risk) was high on all substrata while, under low and intermediate predation risks (long tethers), shrimp mortality was reduced on complex corals relative to that on sand-rubble or massive Porites spp. Overall, mortality was lowest on P. rus. Our study indicates that predation risks constrain shrimp activity and habitat choice, forcing them to hide deep inside complex substrata during the day. Such behavioural responses to predation risks and their consequences for the trophic role of invertebrate mesoconsumers warrant further

Identification of a consistent polyene component of purple pigment in diseased sclerites of Caribbean corals across region, species, and insult agent

NASA Astrophysics Data System (ADS)

Fetterolf, Monty L.; Leverette, Chad L.; Perez, Christopher; Smith, Garriet W.

2017-10-01

Gorgonians respond to insult (damage and disease) by producing sclerites containing a purple pigment as opposed to the normal white sclerites. Raman microscopy is used to study the purple areas of three species of diseased coral, Gorgonia ventalina, Pseudoplexaura porosa, and Eunicea laciniata obtained from Puerto Rico. These spectra were compared to Gorgonia ventalina samples previously reported that were obtained from San Salvador, Bahamas. Spectra from two samples of G. ventalina that had been infected by different agents, Aspergillus sydowii and a slime mold, were also obtained. The results indicate that the purple compounds (polyenes) generated by the coral in response to infection are similar regardless of region from which the coral were harvested, of species of coral, and of the infective agent. A discussion of the Raman spectra of G. ventalina and the other coral species is presented.

Comparing Environmental Influences on Coral Bleaching Across and within Species using Clustered Binomial Regression

EPA Science Inventory

Differential susceptibility among reef-building coral species can lead to community shifts and loss of diversity as a result of temperature-induced mass bleaching events. However, the influence of the local environment on species-specific bleaching susceptibilities has not been ...

Effects of Coral Reef Benthic Primary Producers on Dissolved Organic Carbon and Microbial Activity

PubMed Central

Haas, Andreas F.; Nelson, Craig E.; Wegley Kelly, Linda; Carlson, Craig A.; Rohwer, Forest; Leichter, James J.; Wyatt, Alex; Smith, Jennifer E.

2011-01-01

Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC) release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata – Ochrophyta; Amansia rhodantha – Rhodophyta; Halimeda opuntia – Chlorophyta), a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii) and a dominant hermatypic coral (Porites lobata). Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h−1 dm−2), stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h−1) and concomitant oxygen drawdown (0.16±0.05 µmol L−1 h−1 dm−2). Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence reef

The impact of seawater saturation state and bicarbonate ion concentration on calcification by new recruits of two Atlantic corals

NASA Astrophysics Data System (ADS)

de Putron, S. J.; McCorkle, D. C.; Cohen, A. L.; Dillon, A. B.

2011-06-01

Rising concentrations of atmospheric CO2 are changing the carbonate chemistry of the oceans, a process known as ocean acidification (OA). Absorption of this CO2 by the surface oceans is increasing the amount of total dissolved inorganic carbon (DIC) and bicarbonate ion (HCO3 -) available for marine calcification yet is simultaneously lowering the seawater pH and carbonate ion concentration ([CO3 2-]), and thus the saturation state of seawater with respect to aragonite (Ωar). We investigated the relative importance of [HCO3 -] versus [CO3 2-] for early calcification by new recruits (primary polyps settled from zooxanthellate larvae) of two tropical coral species, Favia fragum and Porites astreoides. The polyps were reared over a range of Ωar values, which were manipulated by both acid-addition at constant pCO2 (decreased total [HCO3 -] and [CO3 2-]) and by pCO2 elevation at constant alkalinity (increased [HCO3 -], decreased [CO3 2-]). Calcification after 2 weeks was quantified by weighing the complete skeleton (corallite) accreted by each polyp over the course of the experiment. Both species exhibited the same negative response to decreasing [CO3 2-] whether Ωar was lowered by acid-addition or by pCO2 elevation—calcification did not follow total DIC or [HCO3 -]. Nevertheless, the calcification response to decreasing [CO3 2-] was nonlinear. A statistically significant decrease in calcification was only detected between Ωar = <2.5 and Ωar = 1.1-1.5, where calcification of new recruits was reduced by 22-37% per 1.0 decrease in Ωar. Our results differ from many previous studies that report a linear coral calcification response to OA, and from those showing that calcification increases with increasing [HCO3 -]. Clearly, the coral calcification response to OA is variable and complex. A deeper understanding of the biomineralization mechanisms and environmental conditions underlying these variable responses is needed to support informed predictions about future OA

Soft Corals Biodiversity in the Egyptian Red Sea: A Comparative MS and NMR Metabolomics Approach of Wild and Aquarium Grown Species.

PubMed

Farag, Mohamed A; Porzel, Andrea; Al-Hammady, Montasser A; Hegazy, Mohamed-Elamir F; Meyer, Achim; Mohamed, Tarik A; Westphal, Hildegard; Wessjohann, Ludger A

2016-04-01

Marine life has developed unique metabolic and physiologic capabilities and advanced symbiotic relationships to survive in the varied and complex marine ecosystems. Herein, metabolite composition of the soft coral genus Sarcophyton was profiled with respect to its species and different habitats along the coastal Egyptian Red Sea via (1)H NMR and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) large-scale metabolomics analyses. The current study extends the application of comparative secondary metabolite profiling from plants to corals revealing for metabolite compositional differences among its species via a comparative MS and NMR approach. This was applied for the first time to investigate the metabolism of 16 Sarcophyton species in the context of their genetic diversity or growth habitat. Under optimized conditions, we were able to simultaneously identify 120 metabolites including 65 diterpenes, 8 sesquiterpenes, 18 sterols, and 15 oxylipids. Principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS) were used to define both similarities and differences among samples. For a compound based classification of coral species, UPLC-MS was found to be more effective than NMR. The main differentiations emanate from cembranoids and oxylipids. The specific metabolites that contribute to discrimination between soft corals of S. ehrenbergi from the three different growing habitats also belonged to cembrane type diterpenes, with aquarium S. ehrenbergi corals being less enriched in cembranoids compared to sea corals. PCA using either NMR or UPLC-MS data sets was found equally effective in predicting the species origin of unknown Sarcophyton. Cyclopropane containing sterols observed in abundance in corals may act as cellular membrane protectant against the action of coral toxins, that is, cembranoids.

Betaines and dimethylsulfoniopropionate as major osmolytes in cnidaria with endosymbiotic dinoflagellates.

PubMed

Yancey, Paul H; Heppenstall, Marina; Ly, Steven; Andrell, Raymond M; Gates, Ruth D; Carter, Virginia L; Hagedorn, Mary

2010-01-01

Most marine invertebrates and algae are osmoconformers whose cells accumulate organic osmolytes that provide half or more of cellular osmotic pressure. These solutes are primarily free amino acids and glycine betaine in most invertebrates and small carbohydrates and dimethylsulfoniopropionate (DMSP) in many algae. Corals with endosymbiotic dinoflagellates (Symbiodinium spp.) have been reported to obtain from the symbionts potential organic osmolytes such as glycerol, amino acids, and DMSP. However, corals and their endosymbionts have not been fully analyzed for osmolytes. We quantified small carbohydrates, free amino acids, methylamines, and DMSP in tissues of the corals Fungia scutaria, Pocillopora damicornis, Pocillopora meandrina, Montipora capitata, Porites compressa, and Porites lobata (all with symbionts) plus Tubastrea aurea (asymbiotic) from Kaneohe Bay, Oahu (Hawaii). Glycine betaine, at 33-69 mmol/kg wet mass, was found to constitute 90% or more of the measured organic solutes in all except the Porites species. Those were dominated by proline betaine and dimethyltaurine. DMSP was found at 0.5-3 mmol/kg in all species with endosymbionts. Freshly isolated Symbiodinium from Fungia, P. damicornis, and P. compressa were also analyzed. DMSP and glycine betaine dominated in the first two; Porites endosymbionts had DMSP, proline betaine, and dimethyltaurine. In all specimens, glycerol and glucose were detected by high-performance liquid chromatography only at 0-1 mmol/kg wet mass. An enzymatic assay for glycerol plus glycerol 3-phosphate and dihydroxyacetone phosphate yielded 1-10 mmol/kg. Cassiopeia andromeda (upside-down jelly; Scyphozoan) and Aiptasia puchella (solitary anemone; Anthozoan) were also analyzed; both have endosymbiotic dinoflagellates. In both, glycine betaine, taurine, and DMSP were the dominant osmolytes. In summary, methylated osmolytes dominate in many Cnidaria; in those with algal symbionts, host and symbiont have similar methylated amino

Identification of a consistent polyene component of purple pigment in diseased sclerites of Caribbean corals across region, species, and insult agent.

PubMed