La grande panne de la technologie américaine / Jean-Claude Derian

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Cochran's The Liquid Metal Fast Breeder Reactor: An Environmental and Economic Critique

Book review

Role of pockmarks in diversity and species assemblages of coastal macrobenthic communities

We used existing bathymetric data to study the macrofauna of a geophysical pockmark field restricted to a benthic habitat engineered by the tubiculous amphipod Haploops nirae in South Brittany (France). Stations inside and outside pockmarks of different morphometric characteristics (location, size, depression depth) were sampled for macrofauna and environmental parameters (sediment characteristics, organic matter, chl a, hydrogen sulfide and methane concentrations). Diversity indices showed higher species richness inside pockmarks, especially for species with medium to high abundances. Most sediment cores showed low methane but high hydrogen sulfide concentrations. We hypothesised that after eruption, the remaining residual methane from pockmark sediments is oxidised by seawater sulfate and accounts for the high sulfide concentrations found at increasing depth in our samples and the low methane concentrations. We found no relationship between sediment profiles and morphometric features of the pockmarks. Macrofauna assemblages inside vs. outside pockmarks appeared to be different. Pockmarks appear to increase connectivity among habitats and heterogeneity within habitats, thereby creating local hotspots that allow the settlement of species that cannot otherwise develop in Haploops tube mats. Multivariate analyses distinguished 4 groups of pockmarks and control stations. We assumed that deeper pockmarks were created more recently than shallow pockmarks and that each pockmark is at a different stage of evolution, hence explaining the large variability in the characteristics of pockmark groups. This explains why previous investigations have found contradictory results when comparing macrofauna species diversity and composition between areas inside and outside pockmarks. Finally, we propose and discuss a successional stage model for pockmarks

Note d'actualite sectorielle: chimie-energie-materiaux

CNRS RP 350 (238) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Supraconductivite: le point des recherches aux Etats-Unis

SIGLECNRS RP 350 (235) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Les programmes de developpement des materiaux avances au ministere americain de la defense

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 10227 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Supraconductivite: strategies et budgets du gouvernement federal americain

CNRS RP 350 (242) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc