Middle Atlantic Outer Continental Shelf Environmental Studies Volume 1: Executive Summary

Increasing demand for petroleum and natural gas in the United States has led to a need for development of reliable new domestic sources. The Outer Continental Shelf of the United States holds great interest among the oil companies for possible exploration and development of oil and gas resources to meet this need. This interest was demonstrated for the Middle Atlantic Outer Continental Shelf in the oil companies\u27 response to the lease sale conducted in August 1976. Of the 154 tracts comprising 876,750 acres offered for lease in August 1975 for exploratory drilling in the Baltimore Canyon Trough (Figure 1), oil compa~ies purchased drilling rights to 101 tracts comprising 575,011 acres. The Bureau of Land Management Environmental Studies Program was established to provide information needed for prediction, assessment, and management of impacts on the human marine and coastal environments of the Outer Continental Shelf and the nearshore area which may be affected by these drilling activities. The studies are designed to: 1. Provide information on the status of the environment upon which the prediction of the impacts of Outer Continental Shelf oil and gas development for leasing decisionmaking may be based, 2. provide information on the ways and extent that Outer Continental Shelf development can potentially impact the human, marine, biological, and coastal areas, 3. ensure that information already available or being collected under the program is in a form that can be used in the decisionmaking process associated with a specific leasing action or with the longer term Outer Continental Shelf minerals management responsibilities, and 4. provide a basis for furture monitoring of Outer Continental Shelf operations

Susceptibility Of Diploid And Triploid Pacific Oysters, Crassostrea Gigas (Thunberg, 1793) And Eastern Oysters, Crassostrea virginica (Gmelin, 1791), To Perkinsus marinus

The susceptibility of Pacific oysters, Crassostrea gigas, to the oyster parasite Perkinsus marinus was compared with that of eastern oysters, Crassostrea virginica, in two separate experiments. Experiments were conducted in flow-through seawater systems with quarantined effluent. Oysters were challenged by addition of infective P. marinus. In the first experiment, which used only diploid oysters, 40% of C. gigas became infected with P. marinus after 83 days compared to 100% of C. virginica. In the second experiment, which examined susceptibility of diploid and triploid individuals of both species, prevalence was high in all groups after 60 days. In C. virginica, heavy and moderate infection intensities prevailed while C. gigas exhibited only light infections. Cumulative mortality of C. virginica after 150 days was 100% for the diploid group and 97.7% for the triploid group. Cumulative mortality of C. gigas after 150 days was 25 .1 % for the diploid group and 34.3% for the triploid group, but this mortality did not appear to be disease related. Thus, C. gigas was consistently more tolerant of P. marinus than was C. virginica, and triploidy provided no increased disease tolerance for either species

The IceCube Neutrino Observatory: Instrumentation and Online Systems

The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.Comment: 83 pages, 50 figures; updated with minor changes from journal review and proofin

The Molecular Diversity of Freshwater Picoeukaryotes Reveals High Occurrence of Putative Parasitoids in the Plankton

Eukaryotic microorganisms have been undersampled in biodiversity studies in freshwater environments. We present an original 18S rDNA survey of freshwater picoeukaryotes sampled during spring/summer 2005, complementing an earlier study conducted in autumn 2004 in Lake Pavin (France). These studies were designed to detect the small unidentified heterotrophic flagellates (HF, 0.6–5 µm) which are considered the main bacterivores in aquatic systems. Alveolates, Fungi and Stramenopiles represented 65% of the total diversity and differed from the dominant groups known from microscopic studies. Fungi and Telonemia taxa were restricted to the oxic zone which displayed two fold more operational taxonomic units (OTUs) than the oxycline. Temporal forcing also appeared as a driving force in the diversification within targeted organisms. Several sequences were not similar to those in databases and were considered as new or unsampled taxa, some of which may be typical of freshwater environments. Two taxa known from marine systems, the genera Telonema and Amoebophrya, were retrieved for the first time in our freshwater study. The analysis of potential trophic strategies displayed among the targeted HF highlighted the dominance of parasites and saprotrophs, and provided indications that these organisms have probably been wrongfully regarded as bacterivores in previous studies. A theoretical exercise based on a new ‘parasite/saprotroph-dominated HF hypothesis’ demonstrates that the inclusion of parasites and saprotrophs may increase the functional role of the microbial loop as a link for carbon flows in pelagic ecosystems. New interesting perspectives in aquatic microbial ecology are thus opened

Interacting effects of temperature and salinity on Bonamia sp. parasitism in the Asian oyster Crassostrea ariakensis

The proposition to introduce the AsianoysterCrassostreaariakensis to the mid-Atlantic region of the USA is being considered with caution, particularly after the discovery of a novel microcell haplosporidian parasite, Bonamiasp., in North Carolina. Although this parasite was found to be pathogenic in C. ariakensis under warm euhaline conditions, its persistence in C. ariakensis exposed to various temperature and salinity combinations remained unresolved. In this laboratory experiment, we tested the influence of temperature in combination with a wide range of salinities (10, 20 and 30 psu) on Bonamiasp. Temperature was either changed from warm (>20 °C) to cold (6 °C for 6 weeks) and back to warm or maintained constant and warm. Warm temperature was associated with higher host mortality than cold temperature, suggesting that temperature influenced Bonamiasp. pathogenicity. The effect of salinity was revealed under warm temperature with highest mortality levels observed in infected C. ariakensis exposed to 30 psu. When temperature was increased following low-temperature exposure, Bonamiasp. was not detected; however sub-optimal experimental conditions may have contributed to this result, making it difficult to draw conclusions regarding the reemergence of the parasite after low-temperature exposure. Although the overwintering of Bonamiasp. in C. ariakensis will need to be further investigated, the results presented here suggest that Bonamiasp. may be able to persist in C. ariakensis under a combination of low temperature and meso- to euhaline salinities.7 page(s