Reef coral reproduction in the equatorial eastern Pacific: Costa Rica, Panamá, and the Galápagos Islands (Ecuador). VII. Siderastreidae, Psammocora stellata and Psammocora profundacella

Two zooxanthellate, scleractinian species present in the equatorial eastern Pacific, Psammocora stellata and Psammocora profundacella, were examined in terms of their reproductive biology and ecology at four study sites, non-upwelling (Ca?o Island, Costa Rica, and Uva Island, Panamá), upwelling (Gulf of Panamá, Panamá), and seasonally varying thermal environments (Galápagos Islands). Both species were gonochoric broadcast spawners lacking zooxanthellae in mature ova. Mature gametes and spawned gonads are present around full moon; however, no spawning was observed naturally or in outdoor aquaria. Mature gametes occurred in P. stellata at Ca?o Island for nearly 6?months, and year round at Uva Island, both non-upwelling sites. Reproductively active colonies occurred mostly in the warmer months in the Gulf of Panamá and Galápagos Islands. In the Galápagos Islands, where collecting effort was greatest for P. profundacella, mature gametes were also most prevalent during the warm season. Annual fecundity was high in both species, 1.3–1.8?×?10⁴?ova?cm^?2?year^?1 in P. stellata and 1.2–2.0?×?10⁴?ova?cm^?2?year^?1 in P. profundacella. Compared to other eastern Pacific corals, P. stellata was relatively resistant to ENSO-related bleaching and mortality, especially populations inhabiting deep (12–20?m) coral communities. Rapid recovery and persistence of Psammocora spp. can be attributed to several factors: (a) relative resistance to bleaching, (b) deep refuge populations, (c) broadcast spawning, (d) protracted seasonal reproduction, (e) high fecundity, and (f) asexual propagation.     

Contaminant source apportionment by PIMMS lead isotope analysis and SEM-image analysis

By combining scanning electron microscopy (SEM) image analysis and laser ablation plasma ionisation multi-collector mass spectrometry (LA-PIMMS), high precision lead isotope analyses can be obtained from individual metal-rich particles. Soils from Wolverhampton and Nottingham were sampled on the basis of high Pb concentrations or brownfield location. Pressed powder pellets of each were rastered by LA-PIMMS to obtain a bulk Pb-isotope signature. The results plot along an apparent mixing line between the major sources of lead contamination in the UK, that is UK ore deposits and alkyl-lead from petrol additives (Australian ore). Two particularly lead-rich soils were chosen to investigate the lead distribution and isotope variability between size and density fractions. The fine-grained and low-density fractions contained most of the lead and have Pb-isotope ratios comparable with the bulk soils. By contrast, the small, lead-enriched denser fractions contained only a minor proportion of the total lead but Pb-isotope signatures indicating relative enrichment in one or other of the end-members from the mixing line. Further characterisation of individual Pb-rich grains is in progress.     

Probability sampling of stony coral populations in the Florida Keys

Principles of probability survey design were applied to guide large-scale sampling of populations of stony corals and associated benthic taxa in the Florida Keys coral reef ecosystem. The survey employed a two-stage stratified random sampling design that partitioned the 251-km(2) domain by reef habitat types, geographic regions, and management zones. Estimates of the coefficient of variation (ratio of standard error to the mean) for stony coral population density and abundance ranged from 7% to 12% for four of six principal species. These levels of survey precision are among the highest reported for comparable surveys of marine species. Relatively precise estimates were also obtained for octocoral density, sponge frequency of occurrence, and benthic cover of algae and invertebrates. Probabilistic survey design techniques provided a robust framework for estimating population-level metrics and optimizing sampling efficiency.