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Transplantation of coral fragments is a common procedure for the restoration of degraded coral reefs. In the Tropical Eastern Pacific (TEP), the branching coral Pocillopora damicornis is the main reef-builder, and it frequently propagates through natural fragmentation; it is therefore a candidate for restoration efforts in this region. To evaluate the usefulness of P. damicornis for reef restoration in the TEP, fragments of three lengths were used: small (1-2 cm), medium (4 cm) and large (7 cm). Fragments of these three sizes were attached on the back-reef, reef flat and reef crest of La Azufrada reef (Gorgona Island, Colombian Pacific). Coral length, width, weight, and survival were followed during 119 days. Furthermore, skeletal density, linear extension and calcification rates of each coral fragment were obtained to evaluate the growth rates as a function of initial size and position on the reef. The overall fragment survival rate was 83.5%, but small fragments survived less, particularly on the back reef, than medium or large fragments. Fragment growth was greatest on the reef flat, whereas medium and large fragments grew faster than small ones. The overall mean of skeletal density, linear extension and calcification rates were 1.70 gCaCO3 cm−3, 1.89 cm yr−1 and 3.16 gCaCO3 cm−2 yr−1, respectively. These growth rates were comparable to those of other reef-building coral species in the world. Growth and survival rates of P. damicornis coral fragments found in this study, suggest that successful and low-cost restoration of TEP coral reefs is feasible using this species. [ABSTRACT FROM AUTHOR]

Coralline algae are an important functional group in coral reef ecosystems. Despite the importance of coralline algae, little is known about their abundance and community structure, especially within Sanya reefs. It was fundamental to study coralline algae species abundance and distribution, and evaluate the effects of environmental factors on the species composition and abundance in Sanya reefs. A total of 24 species in 10 genera were identified based on 11 sampling stations, with the family Corallinaceae being dominant within the study area. The 7 dominant species, which constituted 62.4% of the overall collection, were Amphiroa ephedraea (16.8%), Mesophyllum simulans (11.1%), Porolithon onkodes (9.8%), Neogoniolithon fosliei (7.5%), Mesophyllum mesomorphum (6.6%), Pneophyllum conicum (6.6%) and Hydrolithon boergesenii (4.0%). There was significant spatial variability in the species composition and abundance of coralline algae (ANOSIM: R = 0.356, P = 0.013). The correlation analysis between biotic and abiotic variables indicated that the turbidity had a negative effect and salinity had a positive correlation on the pattern of coralline algae assemblages (global ρ = 0.486, BIOENV analysis). The living cover of coralline algae was greater in deep water than in shallow water at the same sites. This suggests that physical disturbance, either natural or anthropogenic, is more important in regulating the coralline algae community structure in Sanya reefs. [ABSTRACT FROM AUTHOR]

Reduced seawater pH and changes in carbonate chemistry associated with ocean acidification (OA) decrease the recruitment of crustose coralline algae (CCAcf.), an important coral-reef builder. However, it is unclear whether the observed decline in recruitment is driven by impairment of spore germination, or post-settlement processes (e.g. space competition). To address this, we conducted an experiment using a dominant CCA, Porolithon cf. onkodes to test the independent and combined effects of OA, warming, and irradiance on its germination success and early development. Elevated CO2 negatively affected several processes of spore germination, including formation of the germination disc, initial growth, and germling survival. The magnitude of these effects varied depending on the levels of temperature and irradiance. For example, the combination of high CO2 and high temperature reduced formation of the germination disc, but this effect was independent of irradiance levels, while spore abnormalities increased under high CO2 and high temperature particularly in combination with low irradiance intensity. This study demonstrates that spore germination of CCA is impacted by the independent and interactive effects of OA, increasing seawater temperature and irradiance intensity. For the first time, this provides a mechanism for how the sensitivity of critical early life history processes to global change may drive declines of adult populations of key marine calcifiers. [ABSTRACT FROM AUTHOR]

Ocean acidification poses an increasing threat to marine ecosystems and also interacts with other anthropogenic environmental drivers. A planned response strategy could minimize exposure of socioeconomic systems to potential hazards and may even offer wider advantages. Response strategies can be informed by understanding the hazards, assessing exposure and assessing risks and opportunities. This paper assesses exposure of key socioeconomic systems to the hazards of ocean acidification and analyzes the risks and opportunities of this exposure from Small Island Developing States (SIDS) perspectives. Key socioeconomic systems that are likely to be affected by ocean acidification are identified. A risk analysis matrix is developed to evaluate the risks or opportunities arising from ocean acidification. Analysis of the matrix reveals similarities and differences in potential adaptive responses at global and regional levels. For example, while ocean acidification poses significant threats to SIDS from more frequent toxic wild-caught seafood events and, potentially destruction of coral reef structure and habitat, SIDS may have a relative advantage in aquaculture and an important role to play in global marine ecosystem conservation. [ABSTRACT FROM AUTHOR]

The magnitude 9.0 Tohoku earthquake on 11 March 2011 generated a tsunami which caused significant impacts throughout the Pacific Ocean. A description of the tsunami within the lagoons and on the surrounding fringing reefs of two mid-ocean atoll islands is presented using bottom pressure observations from the Majuro and Kwajalein atolls in the Marshall Islands, supplemented by tide gauge data in the lagoons and by numerical model simulations in the deep ocean. Although the initial wave arrival was not captured by the pressure sensors, subsequent oscillations on the reef face resemble the deep ocean tsunami signal simulated by two numerical models, suggesting that the tsunami amplitudes over the atoll outer reefs are similar to that in deep water. In contrast, tsunami oscillations in the lagoon are more energetic and long lasting than observed on the reefs or modelled in the deep ocean. The tsunami energy in the Majuro lagoon exhibits persistent peaks in the 30 and 60 min period bands that suggest the excitation of closed and open basin normal modes, while energy in the Kwajalein lagoon spans a broader range of frequencies with weaker, multiple peaks than observed at Majuro, which may be associated with the tsunami behavior within the more irregular geometry of the Kwajalein lagoon. The propagation of the tsunami across the reef flats is shown to be tidally dependent, with amplitudes increasing/decreasing shoreward at high/low tide. The impact of the tsunami on the Marshall Islands was reduced due to the coincidence of peak wave amplitudes with low tide; however, the observed wave amplitudes, particularly in the atoll lagoon, would have led to inundation at different tidal phases. [ABSTRACT FROM AUTHOR]

The continuing degradation of coral reefs has serious consequences for the provision of ecosystem goods and services to local and regional communities. While climate change is considered the most serious risk to coral reefs, agricultural pollution threatens approximately 25% of the total global reef area with further increases in sediment and nutrient fluxes projected over the next 50years. Here, we aim to inform coral reef management using insights learned from management examples that were successful in reducing agricultural pollution to coastal ecosystems. We identify multiple examples reporting reduced fluxes of sediment and nutrients at end-of-river, and associated declines in nutrient concentrations and algal biomass in receiving coastal waters. Based on the insights obtained, we recommend that future protection of coral reef ecosystems demands policy focused on desired ecosystem outcomes, targeted regulatory approaches, up-scaling of watershed management, and long-term maintenance of scientifically robust monitoring programs linked with adaptive management. [ABSTRACT FROM AUTHOR]

A new Metapeyssonnelia species that comprises up to 7% bottom cover at shallow-water reef habitats in southwest Puerto Rico is described herein. It forms conspicuous orange encrustations on hard substrata and does not grow on living coral as does its two Caribbean congeners. The new species possesses conspicuous, to 30 cm in extent, tightly adherent crusts up to 950 μm thick, only hypobasal calcification, hypothallial cells arranged in broad flabellules and superficial (raised) tetrasporangial and carposporangial nemathecia. Tetrasporangia are pedicellate, borne laterally from cup-like cells that are derived from basal paraphysal cells. Tetrasporangia measure up to 120 μm long and individual carposporangia to 80 μm long. The new species differs from other Metapeyssonnelia species developmentally in that perithallial cells at mid thallus height will divide laterally to form a new hypothallium. Small subunit gene sequences relate the new species to the two Metapeyssonnelia species that are previously known from Puerto Rico. [ABSTRACT FROM AUTHOR]

Highlights: [•] Identifying the baseline state of an ecosystem is a critical step in conservation. [•] Some reef scientists believe that the baseline cover of seaweed was very low. [•] Evidence suggests that macroalgal biomass may have been higher than assumed. [•] Developing context-specific baseline distributions of seaweed is an important goal. [•] Uncertainties illustrate the difficulty of determining the baseline condition. [ABSTRACT FROM AUTHOR]

Water temperature affects the physiology of large benthic foraminifers (LBFs) with algal symbionts dwelling in coral reef environments. However, the detailed physiological responses of LBF holobionts to temperature ranges occurring in their habitats are not known. We report net oxygen (O2) production and respiration rates of three LBF holobionts (Baculogypsina sphaerulata and Calcarina gaudichaudii hosting diatom symbionts, and Amphisorus kudakajimensis hosting dinoflagellate symbionts) measured in the laboratory at water temperatures ranging from 5°C to 45°C in 2.5°C or 5°C intervals and with light saturation levels of ∼500 µmol m−2 s−1. In addition, the recovery of net O2 production and respiration rates after exposure to temperature stress was assessed. The net O2 production and respiration rates of the three LBF holobionts peaked at ∼30°C, indicating their optimal temperature for a short exposure period. At extreme high temperatures (≥40°C), the net O2 production rates of all three LBF holobionts declined to less than zero and the respiration rates slightly decreased, indicating that photosynthesis of algal symbionts was inactivated. At extreme low temperatures (≤10°C for two calcarinid species and ≤5°C for A. kudakajimensis), the net O2 production and respiration rates were near zero, indicating a weakening of holobiont activity. After exposure to extreme high or low temperature, the net O2 production rates did not recover until the following day, whereas the respiration rates recovered rapidly, suggesting that a longer time (days) is required for recovery from damage to the photosystem by temperature stress compared to the respiration system. These results indicate that the oxygen metabolism of LBF holobionts can generally cope well with conditions that fluctuate diurnally and seasonally in their habitats. However, temporal heat and cold stresses with high light levels may induce severe damage to algal symbionts and also damage to host foraminifers. [ABSTRACT FROM AUTHOR]

Abstract: Calcifying green macroalgae of the genus Halimeda are widely distributed on coral reefs and may become more abundant under higher nutrient availability. To determine how nutrient enrichment affects the physiological performance of Halimeda opuntia (Linnaeus) J.V.Lamouroux in relation to different water depths, we carried out in situ nutrient enrichment experiments in Curaçao, Netherlands Antilles. H. opuntia was collected in 5m and then incubated at 5 and 15m in clear acrylic cages with or without addition of N and P. Growth, algal tissue composition (internal C, N, and P content, δ15N signatures, protein content), photosynthetic performance and pigment content were measured after 14 days of incubation. Growth rates and total C increased with nutrients and were higher in 5m water depth. N and P content were higher and δ15N signatures were lighter with nutrients in both depths. Photosynthetic performance, concentrations of the main and accessory photosynthetic pigments, and photoprotection also increased with nutrients and showed some response to depth. These results indicate that nutrient enrichment supported a rapid increase in physiological performance of H. opuntia, but with differences in depth. In 5m, more C was allocated to growth, where light levels were sufficient, while in 15m C was allocated to photosynthetic pigments. These results suggest that nutrient enrichment may influence their abundance and depth distribution on the reef. [Copyright &y& Elsevier]

Abstract: Biochemical and molecular biomarkers tools are utilized as early warning signatures of contaminant exposure to target and non-target organisms. The objective of this study was to investigate the sublethal effects of iron chloride to the larvae of the lace coral Pocillopora damicornis by measuring a suit of oxidative-stress biomarkers. The larvae were exposed to a range of sublethal concentrations of iron chloride (0.01, 0.1, 1, 10, and 100ppm) for seven days. With reference to oxidative stress biomarkers, the no-observed effect concentration (NOEC) and the lowest observed effect concentration (LOEC) of iron chloride were observed to be 0.01 and 100ppm respectively. At the end of the seventh day the antioxidant status of the larvae was evaluated by the levels of glutathione (GSH), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione-S-transferase (GST), in both experimental and control groups. For the quantification of cellular oxidative damage, lipid peroxidation (LPO) activity was determined in the same and the extent of DNA damage was assessed by the expression of DNA apurinic/apyrimidinic (AP) sites. Iron chloride exhibited a concentration-dependent inhibition of GSH and GPX and induction of GR, GST, LPO, and DNA-AP sites in the P. damicornis larvae when compared to the control group. The oxidative stress biomarkers of the larvae exposed to 0.1, 1, and 10ppm of iron chloride did not show any significant overall differences when compared to the control group. However the activities of LPO, GSH, GPX, GR, GST and DNA-AP in the larval group exposed to 100ppm of iron chloride exhibited statistically significant (P =0.002, 0.003, 0.002, 0.002, 0.005 and 0.007) differences when compared to the control group. The research results indicated that iron chloride in concentrations at the 100ppm level caused oxidative stress in the P. damicornis larvae. [Copyright &y& Elsevier]

We examined the importance of picoplankton and virioplankton to reef trophodynamics at Ningaloo Reef, (north-western Australia), in May and November 2008. Picophytoplankton ( Prochlorococcus, Synechococcus and picoeukaryotes), bacterioplankton (inclusive of bacteria and Archaea), virioplankton and chlorophyll a (Chl a) were measured at five stations following the consistent wave-driven unidirectional mean flow path of seawater across the reef and into the lagoon. Prochlorococcus, Synechococcus, picoeukaryotes and bacterioplankton were depleted to similar levels (~40% on average) over the fore reef, reef crest and reef flat (='active reef'), with negligible uptake occurring over the sandy bottom lagoon. Depletion of virioplankton also occurred but to more variable levels. Highest uptake rates, m, of picoplankton occurred over the reef crest, while uptake coefficients, S (independent of cell concentration), were similarly scaled over the reef zones, indicating no preferential uptake of any one group. Collectively, picophytoplankton, bacterioplankton and virioplankton accounted for the uptake of 29 mmol C m day, with Synechococcus contributing the highest proportion of the removed C. Picoplankton and virioplankton accounted for 1-5 mmol N m day of the removed N, with bacterioplankton estimated to be a highly rich source of N. Results indicate the importance of ocean-reef interactions and the dependence of certain reef organisms on picoplanktonic supply for reef-level biogeochemistry processes. [ABSTRACT FROM AUTHOR]

Abstract: Cytotoxic effect of Discosoma sp., Isis hippuris and Nephthea chabrolii extracts on human oral squamous cell carcinoma SCC25 cells was investigated herein. The three marine extracts reduce the cell attachment and exhibit a dose-dependent cytotoxic effect. I. hippuris extract exhibited greater activity in inhibiting cell growth than Discosoma sp. and N. chabrolii. After cells were treated with three extracts, morphological alterations of cells such as rounding and membrane blebbing, nuclear condensation and apoptotic bodies are observed. The three extracts sensitized cells in the G0/G1 and S-G2/M phases with a concomitant significantly increased sub-G1 fraction, determined by flow cytometry. This apoptosis process was accompanied by up-regulation of Fas and activation of caspase-3 expression. These results imply that the three extracts caused apoptosis of SCC25 cells. [Copyright &y& Elsevier]

Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata Verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required. [ABSTRACT FROM AUTHOR]

Ocean acidification is expected to lower the net accretion of coral reefs yet little is known about its effect on coral photophysiology. This study investigated the effect of increasing CO2 on photosynthetic capacity and photoprotection in Acropora formosa. The photoprotective role of photorespiration within dinoflagellates (genus Symbiodinium) has largely been overlooked due to focus on the presence of a carbon-concentrating mechanism despite the evolutionary persistence of a Form II Rubisco. The photorespiratory fixation of oxygen produces phosphoglycolate that would otherwise inhibit carbon fixation though the Calvin cycle if it were not converted to glycolate by phosphoglycolate phosphatase (PGPase). Glycolate is then either excreted or dealt with by enzymes in the photorespiratory glycolate and/or glycerate pathways adding to the pool of carbon fixed in photosynthesis. We found that CO2 enrichment led to enhanced photoacclimation (increased chlorophyll a per cell) to the subsaturating light levels. Light-enhanced dark respiration per cell and xanthophyll de-epoxidation increased, with resultant decreases in photosynthetic capacity ( Pnmax) per chlorophyll. The conservative CO2 emission scenario (A1B; 600–790 ppm) led to a 38% increase in the Pnmax per cell whereas the ‘business-as-usual’ scenario (A1F1; 1160–1500 ppm) led to a 45% reduction in PGPase expression and no change in Pnmax per cell. These findings support an important functional role for PGPase in dinoflagellates that is potentially compromised under CO2 enrichment. [ABSTRACT FROM AUTHOR]

The article presents a study that evaluates the Octocorallia and Scleractinia fauna with regards to their spatial distribution and species association under the influence of water masses in Campos Basin. It mentions that octocorals and stony corals distributions and associations among taxa with water masses were analyzed in which complete dissimilarity was observed between the shallower depth range and middle depth. Result shows that lower slope area were more homogenous while middle slope areas were distinct from one another. It notes that the co-occurrence of octorals indicates the type of habitat and among these species which are indicative of cold-water reef environments include Paragorgia johnsonii, Corallium niobe, and Narella.

The article presents a study on coral reefs sponges in Torres Strait, Queensland. The study focuses on the variation in the abundance and size of coral reefs sponge in five island groups along the central strait including Stephen Island, Yorke Island, and Coconut Island. The study shows that the abundance of sponges varies in three spatial scales and the size frequency distributions of coral reef sponges varied in areas and island groups. The sponges were found skewed and its population was dominated by the small sponges. It concludes that high abundance of sponges does not contribute to its growth and size. Favorable conditions and low disturbances in their habitat can also promote its growth and survival.

The ability of sponges to feed in diverse (including oligotrophic) ecosystems significantly contributes to their ubiquitous aquatic distribution. It was hypothesized that sponges that harbour small amounts of symbiotic bacteria in their pass feed mainly on particulate organic matter (POM). We examined the nearly symbiont-free (by microscopic observation) filter-feeding Red Sea sponge Negombata magnifica in order to: (a) study removal efficiency of naturally occurring organic particles, (b) measure the total amount of absorbed particulate organic carbon (POC) and nitrogen (PON), and (c) estimate organic carbon and nitrogen flux in this sponge. Total amount of organic carbon and nitrogen in the Gulf of Aqaba was found to be 48.46±5.69 μg l-1 and 6.45±0.7 μg I-1, respectively. While detritus contributed 54% of POC, most PON (84%) came from planktonic microorganisms, mainly prokaryotes. Particle removal efficiency ranged from 99% (the cyanobacterium Synechococcus sp.) to 37% (for eukaryotic cells >8pm). On average, N. magnifica ingested 480 μg Cday-1 g-1 (wet mass, WM) sponge and 76.6 μg-1da-1 g-1 sponge. Ingested POC balanced 85% of the sponge's energetic demand but more is needed for biomass production because it cannot digest all of the carbon. 54.4±16.1 μg N day-1 g-1 (WM) nitrogen was excreted as total ammonia nitrogen (TAN); however, nitrogen allowance should be higher because more nitrogen is deposited for sponge biomass during growth. It is hypothesized that the discrepancy in the nutritional requirements should be covered by the sponge absorbing carbon and nitrogen from sources that are not dealt with in the present research, such as dissolved organic carbon and nitrogen. This study highlights the significance of detritus as a carbon source, and prokaryotes as a PON source in sponge feeding. [ABSTRACT FROM AUTHOR]

Abstract: Coralline algae are common components in Messinian reefs in the Sorbas Basin in SE Spain and in the Salento Peninsula (southern Italy). They occur encrusting coral skeletons and other bioclasts, forming rhodoliths, and as fragments in back-reef, reef-framework, and proximal-to-middle slope facies. Corallines also occur in Halimeda boundstones associated to coral reefs. In contrast, no coralline algae have been recorded in the fine-grained distal slope deposits in both areas and in lagoonal marly limestones in Salento. The relative abundance of corallines in reefs and their species richness is significantly higher in the Salento platform than in the intermontane Sorbas Basin, which was affected by terrigenous influx. Neogoniolithon brassica-florida and Spongites fruticulosus dominate the shallow-water assemblages; Lithophyllum records peak at the base of reef-core and upper-slope deposits (around 20 m palaeodepth) and Phymatolithon calcareum and species of Lithothamnion are most abundant in deeper slope facies. The main components of the Messinian Mediterranean reef coralline assemblages are extant species, common in the Mediterranean and along the north Atlantic coast from Morocco (and the Canary Islands) to the British Islands. A few, such as Spongites fruticulosus and Phymatolithon calcareum, have been living in the Mediterranean region for more than 25 Ma. Four species still live in the Indo-Pacific but disappeared from the Mediterranean during the Messinian Salinity Crisis. The typical components of present-day Indo-Pacific coral reefs do not occur in the Mediterranean Messinian reefs. The ‘Mediterranean–Atlantic’ character of the Messinian reef corallines reflects the decrease in tropical biotas in the Mediterranean throughout the Miocene, probably related to global cooling and isolation of the Mediterranean from the Indian Ocean since the Middle Miocene. [Copyright &y& Elsevier]

The article presents a study investigating the growth rates for the coral colony of Acropora palmata in Curaçao. The researchers compared the linear growth measurement of the corals collected from December to November of 1971-1974 and 2002-2004. A linear mixed effect model was utilized to determine repeated measurements. It is found that a significant difference does exist in growth rates of A. palmata collected from 1971-1973 and 2002-2004. The researchers concluded that summer growth was greater as compared to the winter growth of the corals.

The decline of many coral reef ecosystems in recent decades surprised experienced managers and researchers. It shattered old paradigms that these diverse ecosystems are spatially uniform and temporally stable on the scale of millennia. We now see reefs as heterogeneous, fragile, globally stressed ecosystems structured by strong positive or negative feedback processes. We review the causes and consequences of reef decline and ask whether management practices are addressing the problem at appropriate scales. We conclude that both science and management are currently failing to address the comanagement of extractive activities and ecological processes that drive ecosystems (e.g. productivity and herbivory). Most reef conservation efforts are directed toward reserve implementation, but new approaches are needed to sustain ecosystem function in exploited areas. [Copyright &y& Elsevier]

The article reports that scientists around the world are racing to comprehend coral reproduction, as the Earth's besieged corals become the focus of the International Year of the Reef in 2008. The consortium, Sexual Coral Reproduction (SECORE), hopes that by growing the corals in aquaria, they would prevent beleaguered species from extinction. Some studies are paying off. One team, by combining spawning records and satellite climate data, has started to overturn the view that surface water temperatures control the spawning cycle. DNA studies have also unearthed proteins that detect the light and fine-tune the spawning clock.

The article discusses the deep-water corals of the Red Sea. The Red Sea is capable of accommodating benthic ecosystem with its 2000 kilometers marginal basin that is elongated and semi-enclosed. However, the author mentions that the Red Sea has a poor known deep-water coral fauna from the Indian Ocean. It offers a background history of the deep-water corals in the Red Sea, and is accompanied with a chart that suggests the locations and depths of stations of the coral fauna. The author states that the high-salinity phase brought by the Last Glacial epoch was lethal to the stenoecious ecosystem in the Red Sea.

This study is the second of two surveys designed to systematically screen extracts from marine plants for antimicrobial effects against ecologically relevant marine microorganisms, and to compare results on a geographical basis. In the preceding survey, extracts from tropical Atlantic marine algae and seagrasses were screened in growth inhibition assays against the pathogenic fungus Lindra thalassiae, the saprophytic fungus Dendryphiella salina, the saprophytic stramenopiles, Halophytophthora spinosa and Schizochytrium aggregatum, and the pathogenic bacterium Pseudoaltermonas bacteriolytica. In this study, the same assay microorganisms were used to examine the antimicrobial effects of lipophilic and hydrophilic extracts from 54 species of marine algae and two species of seagrasses collected from Indo-Pacific reef habitats. Overall, 95% of all species surveyed in this study yielded extracts that were active against one or more, and 77% yielded extracts that were active against two or more assay microorganisms. Broad-spectrum activity against three or four assay microbes was observed in the extracts from 50 to 21% of all species, respectively. Extracts from the green alga Bryopsis pennata and the red alga Portieria hornemannii inhibited the growth of all assay microorganisms. Given that antimicrobial activity was prevalent among extracts of Indo-Pacific marine plants, it is interesting to note that the inhibitory effects of each extract varied considerably between the assay microorganisms. Overall, H. spinosa and D. salina were the most susceptible while L. thalassiae, S. aggregatum, and P. bacteriolytica were the most resistant to the extracts tested. These results provide good evidence that antimicrobial chemical defenses are widespread among Indo-Pacific marine plants. Further, the activity profiles of plant extracts suggest that antimicrobial secondary metabolites can have pathogen-selective or broad-spectrum effects. To confirm these results, chemical studies will be needed to isolate and characterize the compounds responsible for the observed antimicrobial activities. [ABSTRACT FROM AUTHOR]

Emerging diseases have been responsible for the death of about 30% of corals worldwide during the last 30 years. Coral biologists have predicted that by 2050 most of the world's coral reefs will be destroyed. This prediction is based on the assumption that corals can not adapt rapidly enough to environmental stress-related conditions and emerging diseases. Our recent studies of the Vibrio shiloi/Oculina patagonica model system of the coral bleaching disease indicate that corals can indeed adapt rapidly to changing environmental conditions by altering their population of symbiotic bacteria. These studies have led us to propose the Coral Probiotic Hypothesis. This hypothesis posits that a dynamic relationship exists between symbiotic microorganisms and environmental conditions which brings about the selection of the most advantageous coral holobiont. Changing their microbial partners would allow the corals to adapt to changing environmental conditions more rapidly (days to weeks) than via mutation and selection (many years). An important outcome of the Probiotic Hypothesis would be development of resistance of the coral holobiont to diseases. The following evidence supports this hypothesis: (i) Corals contain a large and diverse bacterial population associated with their mucus and tissues; (ii) the coral-associated bacterial population undergoes a rapid change when environmental conditions are altered; and (iii) although lacking an adaptive immune system (no antibodies), corals can develop resistance to pathogens. The Coral Probiotic Hypothesis may help explain the evolutionary success of corals and moderate the predictions of their demise. [ABSTRACT FROM AUTHOR]

Sponges are the dominant organisms on many coral reefs and through feeding they may greatly reduce the concentration of suspended food particles. Retention efficiencies of the tubular sponges Aplysina lacunosa , Callyspongia vaginalis and Niphates digitalis were examined on a coral reef located in the Florida Keys. Replicate ambient and exhalant water samples were collected in situ from individuals of each species and analysed using two methods. Retention efficiencies of suspended particles (0.75–18  µm) examined using Coulter counter analysis were similar among the three sponge species, averaging 86%. For all sponges, particle retention decreased as particle size increased from 0.7 to 18  µm. Water samples plated on to Marine Agar produced 54 microbial types. Retention efficiencies of culturable microbes were similar among the three species, averaging 82%. This study suggests that the coral reef sponges Aplysina lacunosa , Callyspongia vaginalis and Niphates digitalis play an important role in the transfer of energy between the pelagic and benthic environments. [ABSTRACT FROM AUTHOR]

The impact of grazing by herbivorous fishes (Acanthuridae, Scaridae, and Pomacentridae) on low coral-cover reefs was assessed by measuring rates of benthic algal production and consumption on inshore and offshore reefs in the upper Florida Keys. Algal production rates, determined in situ with caged and uncaged experimental plates, were low (mean 1.05 g C m-2 day-11) and similar among reef types. Algal consumption rates were estimated using two different models, a detailed model incorporating fish bite rates and algal yield-per-bite for one species extrapolated to a guild-wide value, and a general regression relating fish biomass to algal consumption. Algal consumption differed among reef types: a majority of algal production was consumed on offshore reefs (55-100%), whereas consumption on inshore patch reefs was 31-51%. Spatial variation in algal consumption was driven by differences in herbivorous fish species composition, density, and size-structure among reef types. Algal consumption rates also varied temporally due to seasonal declines in bite rates and intermittent presence of large-bodied, vagile, schooling species. Spatial coherence of benthic community structure and temporal stability of algal turf over 3 years suggests that grazing intensity is currently sufficient to limit further spread of macroalgal cover on these low coral-cover reefs, but not to exclude it from the system. [ABSTRACT FROM AUTHOR]

Assessment of the extent of coral bleaching has become an important part of studies that aim to understand the condition of coral reefs. In this study a reference card that uses differences in coral colour was developed as an inexpensive, rapid and non-invasive method for the assessment of bleaching. The card uses a 6 point brightness/saturation scale within four colour hues to record changes in bleaching state. Changes on the scale of 2 units or more reflect a change in symbiont density and chlorophyll a content, and therefore the bleaching state of the coral. When used by non-specialist observers in the field (here on an intertidal reef flat), there was an inter-observer error of ± 1 colour score. This technique improves on existing subjective assessment of bleaching state by visual observation and offers the potential for rapid, wide-area assessment of changing coral condition. [ABSTRACT FROM AUTHOR]

Some authors argue that overfishing is an important reason that reef corals have declined in recent decades. Their reasoning is that overfishing removes herbivores, releasing macroalgae to overgrow and kill the corals. The evidence suggests, however, that global climate change and emergent marine diseases make a far greater contribution to coral mortality, and that macroalgae generally grow on the exposed skeletal surfaces of corals that are already dead. Macroalgal dominance, therefore, is an effect rather than a cause of coral mortality. Marine protected areas (MPAs), which are usually established to protect stocks of reef fish, foster populations of herbivorous fish under at least some circumstances. Increased herbivory can reduce algal cover, potentially accelerating the recovery of coral populations inside MPAs; however, establishing MPAs will have only a limited impact on coral recovery unless policymakers confront the accelerating negative effects of the global-scale sources of coral mortality. [ABSTRACT FROM AUTHOR]

The atoll reefs of the Lakshadweep, in the Indian Ocean suffered a catastrophic mortality of hard coral in the wake of the El Niño event of 1998. This study tracked changes to coral and other benthic elements in three atolls in the Lakshadweep from 2000 to 2003. The recovery of coral was highly site-specific, and appeared to be driven by differences in post-settlement survival of coral recruits, that were in turn, influenced by the local hydrodynamics of the atolls. Post bleaching recovery was highest on west-facing reefs, while recovery on east-facing reefs was very limited. However, no 'phase-shift' to macroalgal dominated reefs was evident. High herbivore pressures were perhaps the most important control of macroalgae. Five years after the mass mortality, the genera that showed the maximum gains represented a mix of different susceptibilities to bleaching, while some genera that were not particularly susceptible to bleaching showed significant declines. These results suggest that decline or recovery of coral is likely dependent on individual life history strategies, post-recruitment survival, and contingency. [ABSTRACT FROM AUTHOR]

The influence of winter and spring/summer mixed algal communities from the low intertidal zone on the growth and physiology of four associated species of scleractinian corals was studied in outdoor culture. Experimental algae and corals came from the fringing reef of Sesoko Island, Okinawa, Japan, where fragments of the corals Acropora hyacinthus, Acropora sp., Porites cylindrica and Pavona divaricata were collected and exposed in aquaria 0.5–1.0 cm above mixed algal associations (AA), consisting of more than 100 species. A 30-day exposure did not show negative influence on algal growth, photosynthesis and respiration for the 4 coral species investigated, in spite of the fact that the AA included algae that are known to be toxic to corals. Moreover, the presence of the spring/winter AA in the aquaria actually stimulated the growth of coral fragments two- to four-fold. The results suggest that even though algal occupancy of the substratum on the fringing reef of Sesoko Island is 90%, it has no negative impact on the growth and physiological state of corals living near the algae. Possible mechanisms of a positive influence of algal communities near, but not in contact with, are organic uptake or enhanced planktonic prey. [ABSTRACT FROM AUTHOR]

Abstract Unusual disease lesions were observed in Montipora corals on the fringing reef of Magnetic Island (Great Barrier Reef, Australia) following a period of high water temperature in early January 2002. Tissue death in Montipora spp. appeared as a black layer that spread rapidly across the colony surface, though this appeared as the final phase of disease progression (with three previous disease phases now identified, S. Anthony, unpublished). Culture and molecular-based microbial analysis of this layer did not identify a likely microbial pathogen. Despite this, DNA sequencing of microbial 16S rDNA indicated a shift in the bacterial population associated with affected coral tissue. A clone library of the healthy coral sample predominantly contained sequences within the ?-Proteobacteria. A disease coral sample representing the margin of the black lesion and healthy coral tissue was dominated by sequences, which demonstrated low sequence identity to a range of a-Proteobacteria, ?-Proteobacteria and cyanobacteria. The microbes identified in the diseased Montipora spp. samples are likely to be opportunistic rather than the causative agent of the observed lesion. Studies are in progress to further characterise the ecology of this disease and describe the potential microbial pathogen(s). [ABSTRACT FROM AUTHOR]

The proximity of a reef to a tropical cyclone path is the simplest means of estimating the potential for disturbance (that is, physical damage from waves) at that reef. Calculated for cyclones that tracked across a sample of reefs spanning much of the Great Barrier Reef (GBR) from 1910 to 1999, such proximities provide a preliminary history of cyclone disturbance in that region for which spatial and temporal trends can be examined. As the long-term dynamics of cyclone disturbance affect the structure and function of coral reef communities, the disturbance regime can be used to consider whether the current state of coral communities (as measured in 1999) represents that which was present over the entire time series, and whether the frequency of cyclone disturbance across the GBR is high (limited recovery time between events) or intermediate (variable recovery time between events) in nature. This analysis reveals that for more than half of the GBR, the latest major disturbance occurred less recently than normal for the time series (current communities had more time for recovery than usual) and that these disturbances are generally intermediate in frequency. However, because many factors other than distance affect the potential for disturbance, these results represent a first step towards characterising the nature of cyclone disturbance across the GBR.ACRONYMSAIMS Australian Institute of Marine ScienceGBR Great Barrier ReefGIS Geographic Information SystemsLTM Long Term Monitoring [ABSTRACT FROM AUTHOR]

The three members of the Montastraea annularis complex (M. annularis, M. franksi, and M. faveolata) are dominant reef builders in the western Atlantic whose species status has been controversial for over a decade. Although differences in colony morphology and reproductive characteristics exist, interspecific fertilizations are possible in the laboratory and genetic differentiation is slight. Here we compare the three taxa genetically and morphologically in Panama and the Bahamas, widely separated locations spanning most of their geographic ranges. In Panama, analyses of three AFLP loci, a noncoding region of the mitochondrial genome, and ITS sequences reveal that M. faveolata is strongly differentiated genetically. Discriminant function analysis also indicates no overlap with the other two species in the fine structure of the corallites that comprise the colony. Genetic analyses of larvae from interspecific crosses between M. faveolata and the other two taxa confirmed the hybrid status of the larvae, but no examples of the most probable F1 genotype were observed in the field. Although M. annularis and M. franksi were more similar, they also exhibited strong frequency differences at two AFLP loci and in the mitochondrial noncoding region, as well as distinct corallite structure. In the Bahamas, in contrast, the three taxa exhibited overlapping morphologies. Montastraea franksi and M. annularis were indistinguishable genetically, and M. faveolata was distinct at fewer genetic loci. Once again, however, the most probable F1 genotype involving M. faveolata was not observed. Geographic differences between Panama and the Bahamas explain why past studies have come to different conclusions concerning the status of the three species. In general, the genetic and morphological data suggest a north to south hybridization gradient, with evidence for introgression strongest in the north. However, reproductive data show no such trend, with intrinsic... [ABSTRACT FROM AUTHOR]

Reef-building corals associate with a diverse array of eukaryotic and noneukaryotic microbes. Best known are dinoflagellates in the genus Symbiodinium ("zooxanthellae"), which are photosynthetic symbionts found in all reef-building corals. Once considered a single species, they are now recognized as several large, genetically diverse groups that often co-occur within a single host species or colony. Variation among Symbiodinium in host identities, tolerance to stress, and ability to colonize hosts has been documented, but there is little information on the ecology of zooxanthellar free-living stages and how different zooxanthellae perform as partners. Other microbial associates of reef corals are much less well known, but studies indicate that individual coral colonies host diverse assemblages of bacteria, some of which seem to have species-specific associations. This diversity of microbial associates has important evolutionary and ecological implications. Most mutualisms evolve as balanced reciprocations that allow partners to detect cheaters, particularly when partners are potentially diverse and can be transmitted horizontally. Thus, environmental stresses that incapacitate the ability of partners to reciprocate can destabilize associations by eliciting rejection by their hosts. Coral bleaching (the loss of zooxanthellae) and coral diseases, both increasing over the last several decades, may be examples of stress-related mutualistic instability. [ABSTRACT FROM AUTHOR]

Focuses on the character release following extinction in a Caribbean reef coral species complex. Comparative taxonomy and morphometric analyses of the montastraea complex; Pleistocene species abundance patterns in Barbados; Relationship between coral growth rates and growth form.

Examines the demographic processes underlying a decline of corals in the Jamaican reefs. Differentiation among Montastrea annularis, Agaricia agaricites and Leptoseris cucullata; Description of the temporal trends in the three coral species; Use of matrix modeling to investigate population decline.

Studies mutualisms among species of coral reef sponges. Symbiosis among the coral reef sponges; Conditions for increase in growth rate; Exchange of branches in neighboring sponges; Identification of the species; Difference in tissue characteristics; Susceptibility to environmental hazards; Strategies to decrease loss rate.

Two new PAM fluorometers (pulse amplitude modulated) were used in an investigation of photosynthetic performance of Prochloron resident as a symbiont in the ascidian Lissoclinum patella, growing in a coral reef of Heron Island on the Great Barrier Reef. With a new DIVING-PAM in situ measurements of effective PSII quantum yield (δF/Fm′) as a function of quantum flux density (rapid light curves) were carried out in 2.5 m depth in the reef and in a seawater tank. Photosynthetic electron transport rates were measured on in hospite Prochloron both in situ and in collected material. Both light-limited and light-saturated yields were exceptionally high. Maximal yields (Fv/Fm) were ˜0.83. A new TEACHING-PAM was employed for analysing dark-light induction and light-dark relaxation kinetics in collected samples with Prochloron in hospite. Considerable variability in kinetic responses was observed which was found to be at least in part due to differences in O2 concentration. It is suggested that endogenous reductants feed electrons into the intersystem transport chain, which normally is reoxidized by O2 (chlororespiration), and that in the dark, the reduction level of PSII acceptors is increased due to a decline in O2 concentration. The pattern of fluorescence responses differed markedly from those found in cyanobacteria and provides new insights into light-harvesting responses of a photosynthetic prokaryote with a membrane bound light-harvesting system, as contrasted with an extrinsic light-harvesting system. [ABSTRACT FROM AUTHOR]

The article presents studies on morphological variations in Sargassum cristaefolium. S. cristaefolium is normally an annual plant. Plants attach to rocks and coral reefs by a discoidal holdfast from the lower intertidal zone in shallow rock and tidal pools to the subtidal zone, about 2 meter deep. Young plants appear in autumn, and become mature in next spring to summer. The stem is less than 1 cm in length and 2-4 mm in diameter, usually without branching. The length of main branches of shallow water, measuring 10-20 cm, is shorter than deep water plants, measuring 20-40 cm.

Focuses on the morphologically variable reef coral previously known as Montastraea annularis, which has been separated into three species. How has it been separated; Investigation of the proposed reclassification; Details on a reciprocal intra- and inter-specifc fertilization experiments; Information on the separation.

A new species of semi-endophytic coralline alga, Lithophyllum cuneatum (Corallinaceae: Lithophylloideae), is described from Fiji. The species is characterized by a wedge-like thallus that is partially buried in the thallus of the host coralline, Hydrolithon onkodes (Heydrich) Penrose et Woelkerling or occasionally Neogoniolithon sp., and that appears at the surface of the host as a small pustule that is usually paler in color than the host. The thallus consists of erect filaments that are derived from a single cell. The basal cell, when visible, is non-palisade, and areas of bistratose margin are absent. Cells of contiguous erect filaments are joined by secondary pit connections. Epithallial cells are present in 2-3 layers, and individual trichocytes are common. Gametangial plants are dioecious. Male conceptacles have simple spermatangial systems that are confined to the floors of their elliptical chambers. Carposporangial conceptacles contain 5-8 celled gonimoblast filaments that are borne at the margin of a more-or-less discoid fusion cell, and so occupy the periphery of the elliptical conceptacle chambers. Tetrasporangial conceptacles are uniporate, with roofs formed from peripheral filaments, and chambers lack a central columella of sterile filaments. Despite its semi-endophytic nature, haustorial cells are absent, and plastids and pigmentation are present. [ABSTRACT FROM AUTHOR]

Two species of the siphonaceous chlorophyte Ostreobium inhabiting the aragonite skeletons of Atlantic and Caribbean reef corals were studied. Ostreobium quekettii Bornet & Flahault has been previously reported from these locations, but the species is here amended to include filament forms previously described under the name O. reineckei Bornet. Ostreobium constrictum sp. N. is described here for the first time. The 2 sympatric species are distinguished on the basis of filament morphology and chloroplast form. [ABSTRACT FROM AUTHOR]

Cassianastraea is an enigmatic colonial Triassic cnidarian first described as a coral but subsequently referred to the Hydrozoa. We report here the first occurrence in Canada of fossils we designate as Cassianastraea sp. from the Williston Lake region of British Columbia. The specimens come from older collections of the Geological Survey of Canada, collected in Upper Triassic (Carnian) strata assigned to either the Ludington or Baldonnel Formations. While well known in reef associations of the former Tethys region, Cassianiastraca is relatively rare in North America. The Carnian Baldonnel Formation contains the earliest coral reefs from the North American craton and we suspect that Cassianastraea sp. also came from this reef association. [ABSTRACT FROM AUTHOR]

Episodes of coral bleaching (loss of the symbiotic dinoflagellates) and coral mortality have occurred with increasing frequency over the past two decades. Although some corals recover from bleaching events, the source of the repopulating symbionts is unknown. Here we show that after bleaching, the adult octocoral Briareum sp. acquire dinoflagellate symbionts (Symbiodinium sp.) from the environment. Uptake of exogenous symbionts provides a mechanism for response to changes in the environment and resilience in the symbiosis. [ABSTRACT FROM AUTHOR]