Porites Astreoides Research Articles

Estructura de las comunidades de corales y octocorales de Isla de Aves, Venezuela, Caribe Nororiental

The Isla de Aves Wildlife Refuge is the northernmost portion of the Venezuelan territory generating 135 000km2 of Exclusive Economic Zone. Studies on coral communities are scarce and old (1970s), due to its location 650km northeast of La Guaira Port and because it has military facilities. To upgrade baseline information we estimated size structure, percent live cover, species composition and abundance of corals and octocorals. We evaluated 16 sites around the island using the AGRRA Protocol (band-transects 10 m2) between 1.5 and 21m depth (n=67 transects), and visual surveys conducted in other five sites. We recorded 2 327 colonies belonging to four hydroid species and 36 species of stony corals in 11 families. The values for diversity, dominance and evenness of the coral community ranged between 0.78 and 2.12 (SW), 0.15 and 0.61 and 0.57 y 0.92 respectively. Most coral species had relative abundance values under 3%, except Porites astreoides (25.57%), Pseudodiploria strigosa (18.22%) and Siderastrea siderea (14.44%). They were represented mostly by smaller colonies, between 3 and 30cm in maximum diameter and between 0 and 5cm high. A total of 13 octocoral species belonging to three families were identified. Pseudopterogorgia americana was the most abundant species. The mean percent of live coral (including hydrocorals) was 22.30% (SE=1.73) (15.45% for dead coral, SE=3.28). Dead coral had the highest percentage of dissimilarity between sites (9.21%) (ANOSIM) and 16.57% contribution (SIMPER analysis). Octocoral live cover ranged from 0 to 21.35% with a mean of 6.38% (SE=0.99). Research on benthic communities of Isla de Aves should continue, especially in the deeper areas, to assess ecological conditions. Rev. Biol. Trop. 62 (Suppl. 3): 115-136. Epub 2014 September 01.

Resultados del monitoreo a largo plazo en los arrecifes de coral en tres lugares de Jamaica: Isla Monkey, “Ciudad Gorgo” y Cayo Sureste.

The global and regional impacts of climate change are having devastating consequences on the coral reef ecosystems of the Caribbean. Long term monitoring are important tool for assessing reef health. Monitoring was established in 2000 in the Bahamas, Belize and Jamaica. Following the pilot project, the program was institutionalized in Jamaica and monitoring was conducted on eight occasions from 2000 to 2010. Monkey Island and Gorgo City near Discovery Bay (both on the north coast) and Southeast Cay at Port Royal on the south coast were selected. Macroalgae dominated the benthic substrate. Monkey Island and Gorgo City had the highest coral cover. Porites astreoides, Montastraea spp., Porites porities, Siderastrea siderea, and Agaricia agaricites were the most common species. Data from this programme have been used in local and regional coral reef assessment and management initiatives. Rev. Biol. Trop. 62 (Suppl. 3): 65-73. Epub 2014 September 01.

Aggregation and cnidae development as early defensive strategies in Favia fragum and Porites astreoides

To survive, corals possess a variety of active and passive defenses. This study examined the effectiveness of aggregation and cnidae development as defensive strategies in enhancing post-settlement survival and growth of two brooding corals, Favia fragum and Porites astreoides, in Bermuda. Growth and survival of solitary and aggregated spat were monitored over seven weeks; cnidae were extracted from surviving spat. F. fragum aggregated spat had higher mortality, slower growth, and more cnidae than solitary spat. On the other hand, aggregation proved beneficial for P. astreoides spat, which had significantly lower mortality, faster growth, and fewer cnidae. Aggregated and solitary F. fragum spat displayed negative correlations between cnidae density and growth, suggesting a trade-off between defense and growth; however, P. astreoides spat did not demonstrate such a trade-off. These differing responses suggest that early patterns of survivorship and defensive strategies are highly species specific and complex.

Community shifts in the surface microbiomes of the coral Porites astreoides with unusual lesions.

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.

Depredación de coral vivo por peces en el Parque Nacional Natural Tayrona, Caribe colombiano

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

Assessing techniques to enhance early post-settlement survival of corals in situ for reef restoration

For degraded coral reef systems with limited larval supply, active restoration techniques may provide a means of replenishing adult coral populations. Settling or seeding large numbers of sexually-produced larvae directly onto denuded substrate is a potential restoration tool that can eliminate the costs associated with rearing coral spat in culturing facilities. However, the long-term potential to enhance recruitment using seeding techniques has generally been limited due to high post-settlement mortality. Using the brooding coral Porites astreoides (Lamarck, 1816), we explored two potential strategies-choosing favorable substrate communities and caging recently settled spat-to enhance early post-settlement survival during seeding efforts. Larvae were collected from adult colonies in the laboratory and, once competent to settle, were seeded directly onto the reef substrate. Settled spat were individually mapped and monitored using fluorescence techniques, and found to have a low survivorship with <3%-15% surviving after 1 mo, and <1% after 5 mo. Techniques to enhance survival, including choice of substrate and post-settlement caging, did not significantly influence the high rates of natural mortality. These results underscore the general lack of knowledge regarding the major factors that drive the magnitude of early post-settlement mortality, and future identification of these mortality factors may lead to suitable techniques to enhance survival in seeding efforts.

Organic and metal contamination in marine surface sediments of Guánica Bay, Puerto Rico

Land based sources of pollution have the potential to adversely impact valuable coral reef ecosystems. In Guánica Bay (Puerto Rico) sediment samples collected and analyzed in 2009 demonstrate unusually high concentrations of total chlordane, total PCBs, nickel and chromium. A variety of other contaminants (total DDT, total PAHs, As, Cu, Hg, and Zn) were also at levels which may indicate sediment toxicity. With the exception of chromium, all of these contaminants were detected in coral tissues (Porites astreoides), although it is unclear at what level these contaminants affect coral health. PCBs and chlordane are environmentally persistent and likely represent legacy pollution from historical uses in close geographic proximity to the Bay. We hypothesize that the high nickel and chromium levels are due to a combination of naturally high Ni and Cr in rock and soils in the watershed, and enhanced (human driven) erosional rates.

Condición de los arrecifes coralinos del Parque Nacional Guanahacabibes, Cuba

En el 2007 se evaluó el estado de salud de los arrecifes coralinos del Parque Nacional Guanahacabibes, Cuba, sobre la base de la condición de las comunidades de corales. Se analizaron indicadores de condición de los corales escleractinios (diámetro máximo, riqueza de especies, enfermedades y mortalidad) a distintas profundidades, en 13 estaciones con diferentes niveles de exposición a los principales fenómenos océano-atmosféricos generadores de oleaje en el área (vientos nortes, sures y alisios). Se identificaron 42 especies de corales pétreos. Las más abundantes fueron: Siderastrea siderea, Montastraea faveolata, Agaricia agaricites y Porites astreoides. El promedio de cobertura de coral vivo varió entre 4.8% y 31.2%, con un promedio general de 17%. El análisis integrado de todos los indicadores de condición de las comunidades de corales sugirió la existencia de dos áreas diferenciadas según la exposición a los vientos y el consecuente efecto del oleaje y los sedimentos. La primera área abarcó el este de la Bahía de Corrientes (entre Uvero Quemado y Cuevas de Pedro), la más resguardada, y donde los indicadores biológicos sugieren un ambiente más favorable. La segunda comprendió la parte occidental más expuesta (entre Veral y Faro Roncali), que presentó la mayor cobertura relativa del conjunto de especies resistentes a la sedimentación, especialmente en 10 y 15 m de profundidad. Estos resultados indican que los arrecifes del Parque Nacional Guanahacabibes no escapan del proceso de degradación que afrontan la mayoría de los arrecifes de la región del Caribe.AbstractIn 2007, a health assessment of coral reefs in the Guanahacabibes National Park, Cuba, was conducted based onthe condition of coral communities. Coral condition indicators (maximum diameter, species richness, diseases andmortality) were evaluated, at different depths in 13 sites with varying exposure levels to the main ocean-atmosphericphenomena that generate waves in the area (north, south and trade winds). Forty two species of stony corals wereidentified. The most abundant species were Siderastrea siderea, Montastraea faveolata, Agaricia agaricites and Porites astreoides. The average coral cover varied between 4.8% and 31.2%, with a general average of 17%. Theintegrated analysis of all condition indicators of coral communities suggested the existence of two distinctive areasaccording to wind exposure and the consequent effect of both waves and sediments. The first area, covering east ofBahía de Corrientes (between Uvero Quemado and Cuevas de Pedro), was more protected and had a more favorableenvironment, as suggested by the biological indicators. The second area was comprised of the western part,was more exposed (between Veral and Faro Roncali), and showed the highest relative cover of species resistant tosedimentation, especially at 10 and 15 m deep. These results indicate that coral reefs at the Guanahacabibes NationalPark do not escape from the degradation process faced by most coral reefs in the Caribbean region.

Tracking Transmission of Apicomplexan Symbionts in Diverse Caribbean Corals

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 consistent with those of other scleractinian coral symbionts. While this study furthers knowledge regarding these symbionts, numerous questions remain to be addressed, particularly in regard to the specific interaction(s) between these apicomplexans and their hosts.

Bacterial shifts associated with coral–macroalgal competition in the Caribbean Sea

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 488:103-117 (2013) - DOI: https://doi.org/10.3354/meps10394 Bacterial shifts associated with coral–macroalgal competition in the Caribbean Sea Kathleen M. Morrow1,2,*, Mark R. Liles1, Valerie J. Paul3, Anthony G. Moss1, Nanette E. Chadwick1 1Department of Biological Sciences, Auburn University, 101 Rouse Life Sciences Building, Auburn, Alabama 36849, USA 2Australian Institute of Marine Science, PMB no. 3, Townsville MC, Townsville, Queensland 4810, Australia 3Smithsonian Marine Station, 701 Seaway Drive, Fort Pierce, Florida 34949, USA *Email: morrow.kathleen@gmail.com ABSTRACT: Present-day coral reefs are impacted by frequent disturbance and increasing global stressors, which provide an environment that supports the growth of alternative dominants, such as macroalgae, sponges, and tunicates, rather than stony corals. Competitively damaging interactions arise between macroalgae and reef-building corals that can involve chemical, physical, and microbial mechanisms. Using 16S rRNA denaturing gradient gel electrophoresis (DGGE), amplicon sequencing, and multivariate analyses, we examined coral- and algae-associated bacterial assemblages along interaction gradients between the common Caribbean stony corals Montastraea faveolata and Porites astreoides and the benthic macroalgae Halimeda opuntia and Dictyota menstrualis. Benthic surveys were conducted in 3 Caribbean locations, and interactions were sampled for bacterial analyses. Both macroalgae were capable of inducing shifts in coral-associated bacteria to an assemblage that more closely resembled macroalgal-associated bacteria. Overall, M. faveolata-associated bacteria were more significantly affected by macroalgal competitors than were P. astreoides-associated bacteria at all sites. Bacteria associated with M. faveolata corals changed during >83% of interactions, even when samples were taken 5 cm away from competing macroalgae. Detectable shifts in coral-associated bacteria at all sampling sites suggest that macroalgae play a large role in coral holobiont health. The degree to which coral species maintain stable microbial assemblages in the face of environmental fluctuations and competitive stress may indicate specific species and coral reefs that have the capacity to resist perturbations and those that may need additional protection in the future. KEY WORDS: Montastraea faveolata · Porites astreoides · Macroalgae · Microbial community · Allelopathy · Benthic survey · Halimeda · Dictyota Full text in pdf format PreviousNextCite this article as: Morrow KM, Liles MR, Paul VJ, Moss A, Chadwick NE (2013) Bacterial shifts associated with coral–macroalgal competition in the Caribbean Sea. Mar Ecol Prog Ser 488:103-117. https://doi.org/10.3354/meps10394 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 488. Online publication date: August 15, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

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

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 6weeks 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.

Evidence for a host role in thermotolerance divergence between populations of the mustard hill coral (Porites astreoides) from different reef environments

Studying the mechanisms that enable coral populations to inhabit spatially varying thermal environments can help evaluate how they will respond in time to the effects of global climate change and elucidate the evolutionary forces that enable or constrain adaptation. Inshore reefs in the Florida Keys experience higher temperatures than offshore reefs for prolonged periods during the summer. We conducted a common garden experiment with heat stress as our selective agent to test for local thermal adaptation in corals from inshore and offshore reefs. We show that inshore corals are more tolerant of a 6-week temperature stress than offshore corals. Compared with inshore corals, offshore corals in the 31°C treatment showed significantly elevated bleaching levels concomitant with a tendency towards reduced growth. In addition, dinoflagellate symbionts (Symbiodinium sp.) of offshore corals exhibited reduced photosynthetic efficiency. We did not detect differences in the frequencies of major (>5%) haplotypes comprising Symbiodinium communities hosted by inshore and offshore corals, nor did we observe frequency shifts ('shuffling') in response to thermal stress. Instead, coral host populations showed significant genetic divergence between inshore and offshore reefs, suggesting that in Porites astreoides, the coral host might play a prominent role in holobiont thermotolerance. Our results demonstrate that coral populations inhabiting reefs <10-km apart can exhibit substantial differences in their physiological response to thermal stress, which could impact their population dynamics under climate change.

Ecological Inferences from a deep screening of the Complex Bacterial Consortia associated with the coral, Porites astreoides

The functional role of the bacterial organisms in the reef ecosystem and their contribution to the coral well-being remain largely unclear. The first step in addressing this gap of knowledge relies on in-depth characterization of the coral microbial community and its changes in diversity across coral species, space and time. In this study, we focused on the exploration of microbial community assemblages associated with an ecologically important Caribbean scleractinian coral, Porites astreoides, using Illumina high-throughput sequencing of the V5 fragment of 16S rRNA gene. We collected data from a large set of biological replicates, allowing us to detect patterns of geographical structure and resolve co-occurrence patterns using network analyses. The taxonomic analysis of the resolved diversity showed consistent and dominant presence of two OTUs affiliated with the order Oceanospirillales, which corroborates a specific pattern of bacterial association emerging for this coral species and for many other corals within the genus Porites. We argue that this specific association might indicate a symbiotic association with the adult coral partner. Furthermore, we identified a highly diverse rare bacterial 'biosphere' (725 OTUs) also living along with the dominant bacterial symbionts, but the assemblage of this biosphere is significantly structured along the geographical scale. We further discuss that some of these rare bacterial members show significant association with other members of the community reflecting the complexity of the networked consortia within the coral holobiont.

Corals Under Threat

Ocean Science![Figure][1] CREDIT: ELIZABETH D. CROOK Rising concentrations of atmospheric CO2 are causing the pH of surface seawater to decrease, posing a threat to coral reefs. Crook et al. examined how calcification of Porites astreoides , an important reef-building coral found in the Caribbean, is affected by the acidity of the seawater in which it grows by measuring samples along a transect spanning a natural gradient of pH and aragonite saturation. Coral calcification rates decreased significantly as pH and aragonite saturation decreased, in a manner consistent with that exhibited by the same species in laboratory carbonate manipulation experiments. This indicates that the corals were not able to respond quickly enough to prevent the impacts of local ocean acidification on their skeletal growth and development, a discouraging message considering the hopes that some have put on the ability of corals to adapt to future ocean conditions. Proc. Natl. Acad. Sci. U.S.A. 110 , 10.1073/pnas.1301589110 (2013). [1]: pending:yes

Convergent mortality responses of Caribbean coral species to seawater warming

Species‐specific responses to disturbance are a central consideration for predicting the composition, dynamics, and function of future communities. These responses may be predictable based on species traits that can be analyzed systematically to understand those characteristics important in determining susceptibility and potential for recovery. Scleractinian coral communities of the Western Atlantic are experiencing increased frequency and severity of extreme thermal disturbance, coral bleaching, and mortality. A conceptual thermal bleaching response model developed in this study suggests multiple susceptibility pathways that can lead corals to partial mortality and the loss of biomass, or complete mortality and the loss of genotypes, with implications for species‐specific persistence and recovery. Coral assessments from annual to semi‐annual surveys at 18 sites in the U.S. Virgin Islands, northeastern Caribbean Sea, before, during, and after the catastrophic 2005 coral bleaching event and during the mild 2010 bleaching event were used to evaluate bleaching, disease, and mortality responses. Three convergent groupings of species emerged based predominantly on their responses to the 2005 event: Type I—high bleaching and initial mortality, no subsequent white disease, and severe losses of cover (exhibited by Agaricia agaricites and branching Porites species); Type II—moderate bleaching and initial mortality, high subsequent white disease prevalence, and severe losses of cover (exhibited by Colpophyllia natans, Montastraea annularis species complex, and M. annularis sensu stricto); Type III—moderate to low bleaching and paling, low to no subsequent white disease, and low to no loss of cover (exhibited by Diploria strigosa, Montastraea cavernosa, Porites astreoides, and Siderastrea siderea). Whole colony mortality was uncommon, even in the most susceptible species, suggesting a potential for recovery among the majority (19 of 27) of scleractinian corals studied. Type II species performed worse than predicted by species traits because of their susceptibility to disease, a factor that needs to be incorporated more fully in models of thermal stress response. Responses of all species to the milder 2010 event were less severe, with limited bleaching and no detectible mortality. Future community composition of Caribbean coral reefs under seawater warming will likely be increasingly dominated by resistant Type III species.

Detecting hyperthermal stress in larvae of the hermatypic coral Porites astreoides: the suitability of using biomarkers of oxidative stress versus heat-shock protein transcriptional expression

Scleractinian coral populations are declining worldwide in response to a variety of factors including increases in sea surface temperatures. To evaluate the effects of predicted elevated seawater temperatures on coral recruitment, larvae from the coral Porites astreoides were exposed to seawater at ambient (27.3 °C) or elevated temperature (30.8 °C) conditions for 4, 24, or 48 h. Following exposure, larvae were tested for survival and settlement, oxidative stress, respiratory demand, and mRNA expression of heat-shock proteins (Hsps) 16 and 60. While elevated temperature had no effect on larval survival, settlement, or expression of Hsps, it did cause a significant increase in larval respiration, oxidative damage (lipid peroxidation), and antioxidant enzyme activity (catalase). The absence of a significant up-regulation of Hsp 16 or 60 expression in response to thermal stress suggests that the transcriptional expression of these genes is a less sensitive diagnostic tool compared to biomarkers of oxidative stress at the temperatures examined. The results of this study provide evidence that enhanced levels of oxidative stress are encountered in zooxanthellae-containing coral larvae in response to elevated temperatures and that this occurrence should be strongly considered for use as a biomarker when monitoring sub-lethal cellular responses to rising sea surface temperatures.

Sponge bioerosion on reef-building corals: Dependent on the environment or on skeletal density?

X-radiographic techniques were used to measure the skeletal density and percentage of bioerosion in Montastraea annularis and Porites astreoides growing in reefs subjected to suboptimal (Veracruz Reef System, VRS) and optimal (Mahahual, MH) environmental conditions for coral reef development. Skeletal density was higher in P. astreoides than in M. annularis and was higher in corals from MH than from the VRS. The percentage of the skeleton excavated by boring sponges was significantly correlated with skeletal density. These results are the first contribution that seeks to understand the interactions of the environment and coral skeletal density on sponge bioerosion and suggest that bioerosion is linked to coral skeletal density rather than to environmental conditions. Finally, based on the differences in growth strategies between the two species, the effects of climate change on sponge bioerosion rates could have repercussions on coral reef biodiversity and community structure.

Effects of predator exclusion on recruit survivorship in an octocoral (Briareum asbestinum) and a scleractinian coral (Porites astreoides)

Recruits of the Caribbean scleractinian coral Porites astreoides and the octocoral Briareum asbestinum were established on artificial substrata and reared on a reef in cages designed to exclude various classes of organisms known to feed on corals. Post-settlement survivorship of recruits was measured for periods of 2 weeks (B. asbestinum) and 1 month (P. astreoides) on East Turtle Reef in the Florida Keys during May and June 2010. Predator exclusion did not affect survivorship among P. astreoides recruits during the study. Recruits of B. asbestinum experienced lower survivorship in treatments that allowed access by fish compared with fish exclusion treatments. The results indicate that predation may be an important determinant of post-settlement mortality among B. asbestinum recruits, and fishes are the primary contributors to predation-induced mortality. B. asbestinum recruit survivorship differed by an order of magnitude between recruits in the control condition and those in the predator exclusion (0.087 and 0.372, respectively). The findings illustrate the need to consider the effects of interactions early in life on the survival, propagation, and recovery of coral populations.

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

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.

Coral Reef Populations in the Caribbean: Is There a Case for Better Protection against Climate Change?

Knowledge of factors that are important in coral reef growth help us to understand how reef ecosystems react following major environmental disturbances due to climate change and other anthropogenic effects. This study shows that despite a range of anthropogenic stressors, corals on the fringing reefs south of Kingston harbour, as well as corals on fringing reefs on the north coast of Jamaica near Discovery Bay can survive and grow. Skewness values for Sidastrea siderea and Porites astreoides were positive (0.85 - 1.64) for all sites, implying more small colonies than large colonies. Coral growth rates are part of a demographic approach to monitoring coral reef health in times of climate change, and linear extension rates (mm·yr −1 ) of Acropora palmata branching corals at Dairy Bull, Rio Bueno, and Pear Tree Bottom on the north coast of Jamaica were c. 50 - 90 mm·year −1 from 2005-2012. The range of small-scale rugosities at the Port Royal cay sites studied was lower than that at the Discovery Bay sites; for example Rio Bueno was 1.05 ± 0.15 and Dairy Bull the most rugose at 2.3 ± 0.16. Diary Bull reef has for several years been the fringing reef with the most coral cover, with a benthic community similar to that of the 1970s. We discuss whether Jamaica can learn from methods used in other Caribbean countries to better protect its coral reefs against climate change. Establishing and maintaining fully-protected marine parks in Jamaica and elsewhere in the Caribbean is one tool to help the future of the fishing industry in developing countries. Developing MPAs as part of an overall climate change policy for a country may be the best way of integrating climate change into MPA planning, management, and evaluation.