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At least 19 recordsLinked to original sources
PubMed1998

[Long-term radiologic evolution of coral implanted in cancellous bone of the lower limb. Madreporic coral versus coral hydroxyapatite].

PURPOSE: The study aimed to compare two successive series of procedure using first pieces of natural madreporic coral, then coralline hydroxyapatite in traumatology. The goal of this work was to evaluate long term radiological features of absorption and influencing factors. MATERIAL: Within six years, 65 pieces were used; only impaction articular fracture on the lateral tibial plateau (31) and calcaneum fractures (23) were included 21 cases completed inclusion criteria. As there were 3 secondary infections, 18 had therefore, an aseptic evolution and were included in this series. METHODS: Absorption was evaluated in five degrees according to the volume of the remaining piece on X-rays. We also took into consideration the position of the pieces and the amount of surfaces in contact with cancellous bone. RESULTS: Among the 18 pieces followed up for more than 19 months (average 40), there were 4 sequestrations (1 tibia, 3 calcaneum), all were natural madreporic coral, the others presented osteointegration. Only natural madreporic coral pieces were absorbed, but never completely and the absorption was slow (3 to 7 years) and never complete. A radiolucent line was present in 7 out of 10 pieces of madreporic coral and none around coralline hydroxyapatite. Three developed favorably. Four were sequestred. Number of surfaces in contact with cancellous bone was correlated with osteointegration. DISCUSSION: The calcium carbonate which makes up the natural madreporic coral pieces is the site of destruction by osteoclasts. The radiolucent line is the specific witness of this biochemical activity. The radiolucent line proceeds sequestrations. No substitute of coralline hydroxyapatite has presented the same sign of peripheral absorption or sequestration. Coralline hydroxyapatite could be the correct coralline material to fill cancellous defect after elevation of an articular depression. In every case, the piece of coral must be fitted in contact with the cancellous bone in the depth of the bone. Conditions of osteoconduction of madreporic coral must be reconsidered. The degree and speed of peripheral absorption must be controlled before weight bearing is allowed.

Adult↗
PubMed2005

The condition of coral reefs in South Florida (2000) using Coral disease and bleaching as indicators.

The destruction of coral reef habitats has occurred at unprecedented levels during the last three decades. Coral disease and bleaching in the Caribbean and South Florida have caused extensive coral mortality with limited recovery, often coral reefs are being replaced with turf algae. Acroporids were once dominant corals and have diminished to the state where they are being considered as endangered species. Our survey assessed the condition of reef corals throughout South Florida. A probability-based design produced unbiased estimates of the spatial extent of ecological condition, measured as the absence or presence and frequency or prevalence of coral diseases and bleaching intensity over large geographic regions. This approach allowed us to calculate a quantifiable level of uncertainty. Coral condition was estimated for 4100 hectares (ha) (or 41.0 km2) of coral reefs in South Florida, including reefs in the Florida Keys National Marine Sanctuary (FKNMS), New Grounds, Dry Tortugas National Park (DTNP), and Biscayne National Park (BNP). The absence or presence of coral disease, 'causal' coral bleaching, partial bleaching and coral paling were not good indicators of overall coral condition. It was more useful to report the prevalence of anomalies that indicated a compromised condition at both the population and community levels. For example, 79% of the area in South Florida had less than 6% of the coral colonies diseased, whereas only 2.2% (97.15 ha) of the sampled area had a maximum prevalence of 13% diseased coral colonies at any single location. The usefulness of 'causal bleaching' might be more important when considering the prevalence of each of the three different states at a single location. For example, paling was observed over the entire area, whereas bleaching and partial bleaching occurred at 19 and 41% of the area, respectively. An index for coral reef condition might integrate the prevalence and species affected by each bleaching state at individual locations. By establishing these baselines, future surveys can examine changes and trends in the spatial distribution of coral conditions in South Florida and able to score the reefs as to their health status.

Animals↗
PubMed2001

Role of endosymbiotic zooxanthellae and coral mucus in the adhesion of the coral-bleaching pathogen Vibrio shiloi to its host.

Vibrio shiloi, the causative agent of bleaching the coral Oculina patagonica in the Mediterranean Sea, adheres to its coral host by a beta-D-galactopyranoside-containing receptor on the coral surface. The receptor is present in the coral mucus, since V. shiloi adhered avidly to mucus-coated ELISA plates. Adhesion was inhibited by methyl-beta-D-galactopyranoside. Removal of the mucus from O. patagonica resulted in a delay in adhesion of V. shiloi to the coral, corresponding to regeneration of the mucus. DCMU inhibited the recovery of adhesion of the bacteria to the mucus-depleted corals, indicating that active photosynthesis by the endosymbiotic zooxanthellae was necessary for the synthesis or secretion of the receptor. Further evidence of the role of the zooxanthellae in producing the receptor came from a study of adhesion of V. shiloi to different species of corals. The bacteria failed to adhere to bleached corals and white (azooxanthellate) O. patagonica cave corals, both of which lacked the algae. In addition, V. shiloi adhered to two Mediterranean corals (Madracis and Cladocora) that contained zooxanthellae and did not adhere to two azooxanthellate Mediterranean corals (Phyllangia and Polycyathus). V. shiloi demonstrated positive chemotaxis towards the mucus of O. patagonica. The data demonstrate that endosymbiotic zooxanthellae contribute to the production of coral mucus and that V. shiloi infects only mucus-containing, zooxanthellate corals.

Animals↗
PubMed2006

Ecological physiology of a coral pathogen and the coral reef environment.

Laboratory studies on the ecological physiology of a coral pathogen were carried out to investigate growth potential in terms of environmental factors that may control coral diseases on reefs. The disease chosen for this study, white plague type II, is considered to be one of the major diseases of Caribbean scleractinian corals, affecting a wide range of coral hosts and causing rapid and widespread tissue loss. It is caused by a single pathogen, the bacterium Aurantimonas coralicida. A series of laboratory experiments using a pure culture of the pathogen was carried out to examine the roles of temperature, pH, and O(2) concentration on growth rate. Results revealed optimal growth between 30 and 35 degrees Celsius, and between pH values of 6 and 8. There was a distinctive synergistic relationship between pH and temperature. Increasing temperature from 25 to 35 degrees Celsius expanded the range of pH tolerance from a minimum of 6.0 down to 5.0. O(2) concentration directly affected growth rate, which increased with increasing O(2). The combined effects of increasing O(2) and increasing temperature resulted in a synergistic effect of more rapid growth. These laboratory results are discussed in terms of the coral host and the range of the environmental factors that occur on coral reefs. We conclude that changing environmental conditions in the reef environment, in particular observed increases in water temperature, may be promoting coral diseases by allowing coral pathogens to expand their ecological niches. In the case of the white plague type II pathogen, elevated temperature would allow A. coralicida to colonize the low pH environment of the coral surface mucopolysaccharide layer as an initial stage of infection. The synergistic effect between temperature and oxygen concentration appeared to be less environmentally relevant for this coral pathogen.

Alphaproteobacteria↗
PubMed2004

Metal contents in Porites corals: Anthropogenic input of river run-off into a coral reef from an urbanized area, Okinawa.

In order to monitor pollutants from urban areas to coral reefs, metal contents in Porites coral samples collected from the Hija River mouth and at nearby sites from the estuary were analyzed. The corals were cleaned by oxidative and reductive treatments to effectively eliminate detritus and organic materials. Metal-to-calcium (Me/Ca) ratios in the samples were determined by ICP-MS. Filtered samples of river water were also measured similarly for metal concentrations. The extent of anthropogenic contribution by riverine input was assessed by comparing the Me/Ca values in corals to those of Rukan-sho, an unpolluted coral reef. High riverine inputs of Mn, Cd, Zn and Ag were observed from Me/Ca values in the coral samples. Manganese in the coral samples showed strong dependence on salinity, varying inversely to the distance from terrestrial sources. Considering a lead background of 25.0 nmol/mol measured in the Rukan-sho corals, Pb/Ca in corals of the Hija River estuary that are two and three times higher may indicate lead enrichment in the river mouth. Because Pb is only moderately high in the Hija River water compared to its concentration in surface seawater, lead may have accumulated in the estuarine water and sediments, resulting in an elevated concentration of lead available for coral uptake.

Animals↗
PubMed2001

The 1997/1998 mass mortality of corals: effects on fish communities on a Tanzanian coral reef.

The abnormally high surface temperatures in the world's oceans during 1997/1998 resulted in widespread coral bleaching and subsequent coral mortality. An experiment was performed to study the effects of this coral mortality as well as the influence of the structural complexity on fish communities on a Tanzanian coral reef. Changes in fish communities were investigated on plots of transplanted corals after 88% of these corals had died. A distinct shift in fish community composition was found, although diversity was not affected. Fish abundance rose by 39% mostly due to an increase in herbivores, which seemed to benefit from enhanced algal growth on the dead corals. Fish abundance, species diversity and community composition were also strongly influenced by the structural complexity provided by the live and dead corals. This suggests that a coral reef can support abundant and diverse fish populations also after the corals have died as long as the reef structure is sustained.

Animals↗
PubMed2001

[The coral reefs and coral communities of Bahía Culebra , Pacific coast of Costa Rica: biological aspects, economic-recreational and diving activities].

The coral reefs (AC) and coral communities on basalts (CCB) or sand (CCA) of Bahía Culebra (Golfo de Papagayo, northern Pacific coast of Costa Rica), were compared with descriptors such as cover percentage, diversity, substrate topographical heterogeneity (I(H)), associated organisms and frequency of recreational-commercial diving activities on them. Sea urchin abundance and I(H) were similar among the three reefal environments. The AC had higher coral cover (ca. 40%) and total live cover (>50%). The CCB had higher macro and calcareous algae (>5%) and sponges (>2%). Associated organisms (>2%) and general diversity (0.6) were higher in the CCA. Branching coral species (Pocillopora spp.) accounted for >40% of total coral cover in the reefs, followed by massive species (ca. 30%). In the CCB, branching species contributed ca. 80% and massive ca. 19%, whilst in the CCA ca. 68% and ca. 29% respectively. This differences could be related with the substrate consolidation and ample depth range of coral communities. Most of the recreational dives were conducted at the CCB; only occasionally the CCA and AC are visited. Interviewed divers had a principal interest on fish and it is precisely at the CCB where highest fish diversity and biomass are observed. Commercial divers tend to prefer the CCB because of their abundance and distribution in the bay. At the outer littoral of Bahía Culebra, diversity of all taxa and live coral cover zonal distribution are generally higher. In addition to these descriptors, indexes that indicate the regional value of a particular reef or coral community is recommended. Coastal infrastructure is mainly concentrated at three areas of the bay; one of them harbors a rare Leptoseris papyracea reef (the only reported so far in the eastern Pacific) and the solely Costa Rican living population of the free living coral Fungia (Cycloseris) curvata. A resort marina will be built over this reef. A protection plan for this and other reefal environments of Bahía Culebra is urgent and must include the monitoring of environmental variables and coral health.

Animals↗
PubMed2003

Monitoring the coral disease, plague type II, on coral reefs in St. John, U.S. Virgin Islands.

In July 1997, conspicuous white patches of necrotic tissue and bare skeleton began to appear on scleractinian corals in several bays around St. John, US Virgin Islands. Analysis of diseased coral tissue from five different species confirmed the presence of a Sphingomonas-like bacterium, the pathogen for plague type II. To date, 14 species of hard corals have been affected by plague type II around St. John. This disease was monitored at Haulover and Tektite Reefs at depths of 7-12 meters. The study site at Tektite Reef has > 50% cover by scleractinian corals with 90% of hard corals being composed of Montastraea annularis. Monthly surveys at Tektite Reef from December 1997 to May 2001 documented new incidence of disease (bare white patches of skeleton) every month with associated loss of living coral and 90.5% of all disease patches occurred on M. annularis. The frequency of disease within transects ranged from 3 to 58%, and the area of disease patches ranged from 0.25 to 9000 cm2. The average percent cover by the disease within 1 m2 ranged from 0.01% (+/- 0.04 SD) to 1.74% (+/- 9.08 SD). Photo-monitoring of 28 diseased corals of 9 species begun in September 1997 at Haulover Reef revealed no recovery of diseased portions with all necrotic tissue being overgrown rapidly by turf algae, usually within less than one month. Most coral colonies suffered partial mortality. Very limited recruitment (e.g., of Agaricia spp., Favia spp. and sponges) has been noted on the diseased areas. This coral disease has the potential to cause more loss of live coral on St. John reefs than any other stress to date because it targets the dominant reef building species, M. annularis.

Animals↗
PubMed2006

The role of zooxanthellae in the thermal tolerance of corals: a 'nugget of hope' for coral reefs in an era of climate change.

The ability of coral reefs to survive the projected increases in temperature due to global warming will depend largely on the ability of corals to adapt or acclimatize to increased temperature extremes over the next few decades. Many coral species are highly sensitive to temperature stress and the number of stress (bleaching) episodes has increased in recent decades. We investigated the acclimatization potential of Acropora millepora, a common and widespread Indo-Pacific hard coral species, through transplantation and experimental manipulation. We show that adult corals, at least in some circumstances, are capable of acquiring increased thermal tolerance and that the increased tolerance is a direct result of a change in the symbiont type dominating their tissues from Symbiodinium type C to D. Our data suggest that the change in symbiont type in our experiment was due to a shuffling of existing types already present in coral tissues, not through exogenous uptake from the environment. The level of increased tolerance gained by the corals changing their dominant symbiont type to D (the most thermally resistant type known) is around 1-1.5 degrees C. This is the first study to show that thermal acclimatization is causally related to symbiont type and provides new insight into the ecological advantage of corals harbouring mixed algal populations. While this increase is of huge ecological significance for many coral species, in the absence of other mechanisms of thermal acclimatization/adaptation, it may not be sufficient to survive climate change under predicted sea surface temperature scenarios over the next 100 years. However, it may be enough to 'buy time' while greenhouse reduction measures are put in place.

Acclimatization↗
PubMed2006

Indirect effects of algae on coral: algae-mediated, microbe-induced coral mortality.

Declines in coral cover are generally associated with increases in the abundance of fleshy algae. In many cases, it remains unclear whether algae are responsible, directly or indirectly, for coral death or whether they simply settle on dead coral surfaces. Here, we show that algae can indirectly cause coral mortality by enhancing microbial activity via the release of dissolved compounds. When coral and algae were placed in chambers together but separated by a 0.02 mum filter, corals suffered 100% mortality. With the addition of the broad-spectrum antibiotic ampicillin, mortality was completely prevented. Physiological measurements showed complementary patterns of increasing coral stress with proximity to algae. Our results suggest that as human impacts increase and algae become more abundant on reefs a positive feedback loop may be created whereby compounds released by algae enhance microbial activity on live coral surfaces causing mortality of corals and further algal growth.

Animals↗
PubMed2004

The ecotoxicology of vegetable versus mineral based lubricating oils: 3. Coral fertilization and adult corals.

Biodegradable vegetable-derived lubricants (VDL) might be less toxic to marine organisms than mineral-derived oils (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested. In this laboratory study, adult corals and coral gametes were exposed to various concentrations of a two-stroke VDL-1A and a corresponding MDL to determine which lubricant type was more toxic to each life stage. In the fertilization experiment, gametes from the scleractinian coral Acropora microphthalma were exposed to water-accommodated fractions (WAF) of VDL-1A and MDL for four hours. The MDL and VDL-1A WAFs inhibited normal fertilization of the corals at 200 microg l(-1) total hydrocarbon content (THC) and 150 microg l(-1) THC respectively. Disturbance of a stable coral-dinoflagellate symbiosis is regarded as a valid measure of sub-lethal stress in adult corals. The state of the symbiosis in branchlets of adult colonies of Acropora formosa was monitored using indicators such as dinoflagellate expulsion and dark-adapted photosystem II yields of dinoflagellate (using pulse amplitude modulation fluorescence). An effect on symbiosis was measurable following 48 h exposure to the lubricants at concentrations of 190 microg l(-1) and 37 microg l(-1) THC for the MDL and VDL-1A respectively. GC/MS revealed that the main constituent of the VDL-1A WAF was the compound coumarin, added by the manufacturer to improve odour. The fragrance containing coumarin was removed from the lubricant formulation and the toxicity towards adult corals re-examined. The coumarin-free VDL-2 exhibited significantly less toxicity towards the adult corals than all of the other oil types tested, with the only measurable effect being a slight but significant drop in photosynthetic efficiency at 280 microg l(-1).

Animals↗
PubMed2003

The use of coral nubbins in coral reef ecotoxicology testing.

While there is an urgent demand to establish reliable ecotoxicological assays for reef corals, there has not been yet an available source material that can supply the high number of colony replicates needed for reliable tests. In past experiments, the major obstacle to obtaining as many fragments as possible had been the damage inflicted to donor colonies by pruning. In this paper, we present the application of coral nubbins, a novel source material for coral ecotoxicology assays. Nubbins from the branching Red Sea coral Stylophora pistillata (n>450) were used for evaluating the impacts of water soluble fractions from a crude oil, an oil dispersant and dispersed oil. Coral nubbins (minute coral fragments in the size of one to several polyps) harvested from a single colony are genetically identical to each other, may be obtained in any quantity needed and whenever research activities demand their use. Several dozens of nubbins can be obtained from a single small branch in branching coral species, a procedure that has minimal impact on donor genotypes. Nubbins production is a low cost procedure and requires limited maintenance space. Results of short and long-term acute ecotoxicological tests are revealed and discussed here, indicating the advantageous use of nubbins as ubiquitous coral material for toxicology assays and physiological studies.

Animals↗
PubMed1995

Induction of 70-kD heat shock protein in scleractinian corals by elevated temperature: significance for coral bleaching.

In this study, the induction of the 70-kD family of heat shock proteins (hsp70) has been examined in stony coral tissues. In these experiments, the only difference from control conditions has been exposure to a temperature approximating that at which field bleaching in the Caribbean is known to occur, approximately 30 degrees C or 1 degree-2 degrees C above long-term average seasonal maximum temperatures. A constitutive hsp70 has been identified both in the zooxanthellate (hermatypic) coral, Montastrea annularis, and in two corals lacking symbiotic algae, Tubastrea cocchinea and Astrangia danae (Cnidaria, Anthozoa, Scleractinia). Western blots of experimental tissues fractionated by polyacrylamide gel electrophoresis indicate that the initial induction of hsp70 occurs rapidly, within one hour of transfer to water of elevated temperature. Thereafter, the level of hsp70 decreases within 12-24 hours to approximately the constitutive level. In field-bleached specimens of M. annularis, hsp70 is not detected. Since this coral tissue, once bleached to whiteness, contains no 70-kD heat shock protein, we conclude that the process of coral bleaching might include, among other metabolic alterations, a failed heat shock response. In addition to being compromised in other normal functions, the bleached coral would lose the capacity to protect itself against environmental stress. The eventual loss of algae by bleached coral is likely to be consequent to several metabolic changes in the coral tissue. However, the uncoupling of that symbiotic relation is not concomitant with the initial stress response of heat shock protein synthesis.

Animals↗
PubMed2004

Coral cover and partial mortality on anthropogenically impacted coral reefs at Eilat, northern Red Sea.

A photographic analysis was conducted at five shallow reef sites (5-6 m) at Eilat (northern Red Sea) to study changes in live coral cover during a 2-year period. Logit regression analysis showed that levels of total oxidized nitrogen (TON; NO(2)+NO(3)) and the presence of SCUBA divers were significant explicative variables of coral partial mortality, while sedimentation rate was not significant. Sites exposed to mean TON levels above 0.4 microM TON showed significantly lower live stony coral cover and abundance per m(2), and higher partial mortality of coral colonies than sites exposed to lower TON. These findings may be useful in establishing limits for TON levels at Eilat, but must be interpreted with caution due to the complexity of nutrient dynamics in coral reefs, the uncertainty of the effects of nutrients on coral physiological processes, and the possibility of interactions among multiple coral stressors.

Animals↗
PubMed2005

Cellular diagnostics and coral health: declining coral health in the Florida Keys.

Coral reefs within the Florida Keys are disappearing at an alarming rate. Coral cover in the Florida Keys National Marine Sanctuary declined by 38% from 1996 to 2000. In 2000, populations of Montastraea annularis at four sites near Molasses Reef within the Florida Keys National Marine Sanctuary and one reef within Biscayne National Park were sampled on a quarterly basis. Anecdotal observations showed corals at Alina's Reef in Biscayne National Park appeared healthy in March, but experienced an acute loss of coral cover by August. Cellular Diagnostic analysis indicated that Alina's Reef corals were in distress: they had been afflicted with a severe oxidative damaging and protein-denaturing stress that affected both the corals and their symbiotic zooxanthellae. This condition was associated with a significant xenobiotic detoxification response in both species, reflecting probable chemical contaminant exposure. These results demonstrate that applying a Cellular Diagnostic approach can be effective in helping to identify stress and its underlying causes, providing diagnostic and prognostic biomarkers of coral health.

Analysis of Variance↗
PubMed2003

Partial mortality in massive reef corals as an indicator of sediment stress on coral reefs.

Partial mortality and fission on colonies of four common massive coral species were examined at sites differing in their exposure to river sediments in St. Lucia, West Indies. Rates of partial mortality were higher close to the river mouths, where more sediments were deposited, than away from the rivers in two coral species. Frequency of fission showed no significant trend. The percent change in coral cover on reefs from 1995 to 1998 was negatively related to the rate of partial mortality estimated in 1998 in all species. This suggests that partial mortality rates could reflect longer-term temporal changes in coral communities. Similar conclusions could also be reached using a less precise measure and simply recording partial mortality on colonies as <50% and >/=50% dead tissue. We conclude that partial mortality in some species of massive reef corals, expressed as the amount of dead tissue per colony, could provide a rapid and effective means of detecting sediment stress on coral reefs.

Anthozoa↗
PubMedDate not supplied

Nitrogen and photosynthetic function of hermatypic corals. Oxygen exchange of Stylophora pistillata coral under artificial feeding.

The change of Stylophora pistillata coral photosynthetic function (oxygen exchange and biomass of symbionts) under starvation and food enrichment was studied to understand the role of heterotrophy in nitrogen supplements of zooxanthellae. The starvation caused the decrease of frequency of zooxanthellae cells division in 7-10 times. The number of degraded algae cells increased in same proportion and, as a result, the density of zooxanthellae in corals decreased about two times during one-two weeks. Under starvation corals kept their photosynthetic capacity at the level of corals in situ by means of enhancing the zooxanthellae gross photosynthesis. The respiration rate of coral had tendency to increase and the dry mass of polyp tissue to decrease. Under artificial feeding which was following starvation the zooxanthellae density increased in 1.5-2 times, and particular food caused more intensive accumulation of zooxanthellae comparing to dissolved inorganic ammonium. The feeding regime did not affect dry mass of polyp tissue and chlorophyll content as well as respiration and gross productivity of the corals. The conclusion about high effectiveness of particular feeding for supplying symbiotic algae with nitrogen was made and trophic status of zooxanthellae in hospite was determined as unlimited by nitrogen.

Animals↗
PubMed2000

Rapid transition in the structure of a coral reef community: the effects of coral bleaching and physical disturbance.

Coral reef communities are in a state of change throughout their geographical range. Factors contributing to this change include bleaching (the loss of algal symbionts), storm damage, disease, and increasing abundance of macroalgae. An additional factor for Caribbean reefs is the aftereffects of the epizootic that reduced the abundance of the herbivorous sea urchin, Diadema antillarum. Although coral reef communities have undergone phase shifts, there are few studies that document the details of such transitions. We report the results of a 40-month study that documents changes in a Caribbean reef community affected by bleaching, hurricane damage, and an increasing abundance of macroalgae. The study site was in a relatively pristine area of the reef surrounding the island of San Salvador in the Bahamas. Ten transects were sampled every 3-9 months from November 1994 to February 1998. During this period, the corals experienced a massive bleaching event resulting in a significant decline in coral abundance. Algae, especially macroalgae, increased in abundance until they effectively dominated the substrate. The direct impact of Hurricane Lili in October 1996 did not alter the developing community structure and may have facilitated increasing algal abundance. The results of this study document the rapid transition of this reef community from one in which corals and algae were codominant to a community dominated by macroalgae. The relatively brief time period required for this transition illustrates the dynamic nature of reef communities.

Animals↗