Showing papers on "Porites compressa published in 2013"

The distribution of the thermally tolerant symbiont lineage (Symbiodinium clade D) in corals from Hawaii: correlations with host and the history of ocean thermal stress.

Abstract: Spatially intimate symbioses, such as those between scleractinian corals and unicellular algae belonging to the genus Symbiodinium, can potentially adapt to changes in the environment by altering the taxonomic composition of their endosymbiont communities. We quantified the spatial relationship between the cumulative frequency of thermal stress anomalies (TSAs) and the taxonomic composition of Symbiodinium in the corals Montipora capitata, Porites lobata, and Porites compressa across the Hawaiian archipelago. Specifically, we investigated whether thermally tolerant clade D Symbiodinium was in greater abundance in corals from sites with high frequencies of TSAs. We recovered 2305 Symbiodinium ITS2 sequences from 242 coral colonies in lagoonal reef habitats at Pearl and Hermes Atoll, French Frigate Shoals, and Kaneohe Bay, Oahu in 2007. Sequences were grouped into 26 operational taxonomic units (OTUs) with 12 OTUs associated with Montipora and 21 with Porites. Both coral genera associated with Symbiodinium in clade C, and these co-occurred with clade D in M. capitata and clade G in P. lobata. The latter represents the first report of clade G Symbiodinium in P. lobata. In M. capitata (but not Porites spp.), there was a significant correlation between the presence of Symbiodinium in clade D and a thermal history characterized by high cumulative frequency of TSAs. The endogenous community composition of Symbiodinium and an association with clade D symbionts after long-term thermal disturbance appear strongly dependent on the taxa of the coral host.

Terrigenous sediment impact on coral recruitment and growth affects the use of coral habitat by recruit parrotfishes (F. Scaridae)

Abstract: Some major anthropogenic stressors have impacts that occur at infrequent, unpredictable intervals; their effects are difficult to evaluate in a timely manner unless space is substituted for time. In this paper we substitute space for time along an environmental gradient that aliases a predicted temporal response to habitat restoration. We herein describe a 3-year study that combined field experiments and descriptive surveys of a fringing reef at Pelekane Bay, west Hawaii, along a sedimentation gradient from an intermittent stream that episodically discharges from the Kohala Watershed. This degraded watershed is now being restored by grazer exclusion, habitat engineering, and replanting of native flora. Sediment traps, arrays of settling plates, marked branches of endemic finger coral Porites compressa, together with surveys of benthic composition, densities of recruits of economically important parrotfishes, and the relative use of corals by fish recruits, were evaluated during the summers of 2010–2012. As expected, sediment accumulation rate decreased while all coral metrics and the densities, use, and preference of corals by recruit fishes generally increased with distance from the point of sediment discharge. Proportionate abundances of recruit through large adult-sized parrotfishes, overlayed on distributions (mapped by separate study) of sediment impact, allowed us to estimate, as an example, the amount and value of parrotfish rersources that are being unrealized because of sediment impacts on recruit parrotfish. Our Pelekane Bay case study thus illustrates how “space-for-time” substitution can be efficiently applied in an evaluation of potential watershed reclamation of reef resources—at a time considerably prior to likely temporal responses of the reef and its resources to watershed restoration.

Coral Pigments: Quantification Using HPLC and Detection by Remote Sensing

Abstract: Widespread coral bleaching (loss of pigments of symbiotic dinoflagellates), and the corresponding decline in coral reef health worldwide, mandates the monitoring of coral pigmentation. Samples of the corals Porites compressa and P. lobata were collected from a healthy reef at Puako, Hawaii, and chlorophyll (chl) a, peridinin, and Beta-carotene (Beta-car) were quantified using reverse-phase high performance liquid chromatography (HPLC). Detailed procedures are presented for the extraction of the coral pigments in 90% acetone, and the separation, identification, and quantification of the major zooxanthellar pigments using spectrophotometry and a modification of the HPLC system described by Mantoura and Llewellyn (1983). Beta-apo-8-carotenal was found to be inadequate as in internal standard, due to coelution with chl b and/or chl a allomer in the sample extracts. Improvements are suggested, which may result in better resolution of the major pigments and greater accuracy in quantification. Average concentrations of peridinin, chl a, and Beta-car in corals on the reef were 5.01, 8.59, and 0.29, micro-grams/cm(exp 2), respectively. Average concentrations of peridinin and Beta-car did not differ significantly between the two coral species sampled; however, the mean chl a concentration in P. compressa specimens (7.81 ,micro-grams/cm(exp 2) was significantly lower than that in P. lobata specimens (9.96 11g/cm2). Chl a concentrations determined spectrophotometrically were significantly higher than those generated through HPLC, suggesting that spectrophotometry overestimates chl a concentrations. The average ratio of chl a-to-peridinin concentrations was 1.90, with a large (53%) coefficient of variation and a significant difference between the two species sampled. Additional data are needed before conclusions can be drawn regarding average pigment concentrations in healthy corals and the consistency of the chl a/peridinin ratio. The HPLC pigment concentration values contribute to the limited database of pigment concentrations in healthy corals, from which quantitative definitions of 'healthy' vs. 'bleached' coral may emerge. They also serve as ground-truth, corresponding to fluorescence data collected from the reef at Puako using airborne remote sensing of laser induced fluorescence. Fluorescence spectra from several overflights using the NASA AOL (airborne oceanographic lidar) system show consistent chlorphyll fluorescence peaks around 685 nm, as well as consistence peaks in the 400-600 nm range which may emanate from granules in the coral tissue. These data, along with results from previous studies of coral fluorescence, suggest that remote sensing of laser-induced fluorescence may become a rapid and efficient means of monitoring coral pigmentation and coral reef bleaching.

Assessment of coral health in the coastal areas of the Persian Gulf

Abstract: In this study, Zooxanthellae density, chlorophyll a concentration, and mitotic index (MI) were measured in the coral Porites compressa obtained from coastal areas of the Persian Gulf in early February to September 2008. During the summer, zooxanthellae density declined by approximately 30% compared to the winter peak (3,607,849 ± 229,894, n = 15) and reached a minimum of 2,536,732 ± 169,776, n = 15. The highest value of chlorophyll a (0.828 ± 0.043 μg/cm2) was recorded in the south while the lowest (0.604 ± 0.048 μg/cm2) was measured in the north sampling site at the cold season. There was a higher level of MI in the warm season followed by cold > and temperate seasons. The MI were significantly higher (p < 0.05) in the warm and cold seasons in comparison with the temperate season. Differences in response may be attributed to the drastic seasonal temperature changes. However, the significant decline found in the north sampling site indicates that anthropogenic stressors may adversely affect coral P. compressa. These results imply that there were negative impacts on coral P. compressa in our study site.