No abstract

No abstract

We examined the geographic extent of petroleum hydrocarbon contamination in sediment, seawater, biota, and seafood during/after the BP/Deepwater Horizon Oil Spill (April 20-July 15, 2010; 28.736667°N, -88.386944°W). TPH, PAHs, and 12 compound classes were examined, particularly C1-benzo(a)anthracenes/chrysenes, C-2-/C-4-phenanthrenes/anthracenes, and C3-naphthalenes. Sediment TPH, PAHs, and all classes peaked near Pensacola, Florida, and Galveston, Texas. Seawater TPH peaked off Pensacola; all of the above classes peaked off the Mississippi River, Louisiana and Galveston. Biota TPH and PAHs peaked near the Mississippi River; C-3 napthalenes peaked near the spill site. Seafood TPH peaked near the spill site, with PAHs and all classes peaking near Pensacola. We recommend that oil concentrations continued to be monitored in these media well after the spill has ceased to assist in defining re-opening dates for fisheries; closures should be maintained until hydrocarbon levels are deemed within appropriate limits.

During a study of planulation in the central region of the Great Barrier Reef, it was determined that the coral Seriatopora hystrix Dana exhibits an escape response to environmental stress. Th.is response, which occurs relatively rapidly, has been termed 'polyp bail-out', It proceeded in 3 steps: (1) Isolation of individual polyps via the polyp-ward movement of coenosarc; (2) emergenceof polyps and detachment from the skeleton; (3) dispersal, re-attachment to the bottom, andsecretion o i a new skeleton. Of the 250 polyps observed 4 5 % successfully settled and secreted skeletons within 7 to 9 d under laboratory conditions. Polyps retained zooxantheIlae during the process and usually possessed 2 slightly adhesive filaments which may have assisted in re-attachment. Bail-out may be induced at any time in the laboratory and has been observed to occur naturally in the field on several occasions. The peak period of planulation for S. hystrix was determined to be November (early summer, southern hemisphere) During the normal spawning period, some polyps were observed to detach themselves while carrying active planulae. These polyps later disintegrated, releasing the larvae which settled normally. It is suggested that 'bail-out' may be one factor contributing to doininance of this species within certain reef habitats. It would also appear that this process of isolation and detachment of individuals from a coral followed by dispersal, re-settlement, and re-initiation of skeletenogenesis, represents a previously unknown mode of asexual reproduction in the Scleractinia.

No abstract