22 resultados para Purshia tridentata.
em Publishing Network for Geoscientific
Resumo:
In 1986 participants of the Benthos Ecology Working Group of ICES conducted a synoptic mapping of the infauna of the southern and central North Sea. Together with a mapping of the infauna of the northern North Sea by Eleftheriou and Basford (1989, doi:10.1017/S0025315400049158) this provides the database for the description of the benthic infauna of the whole North Sea in this paper. Division of the infauna into assemblages by TWINSPAN analysis separated northern assemblages from southern assemblages along the 70 m depth contour. Assemblages were further separated by the 30, 50 m and 100 m depth contour as well as by the sediment type. In addition to widely distributed species, cold water species do not occur further south than the northern edge of the Dogger Bank, which corresponds to the 50 m depth contour. Warm water species were not found north of the 100 m depth contour. Some species occur on all types of sediment but most are restricted to a special sediment and therefore these species are limited in their distribution. The factors structuring species distributions and assemblages seem to be temperature, the influence of different water masses, e.g. Atlantic water, the type of sediment and the food supply to the benthos.
Resumo:
At present time, there is a lack of knowledge on the interannual climate-related variability of zooplankton communities of the tropical Atlantic, central Mediterranean Sea, Caspian Sea, and Aral Sea, due to the absence of appropriate databases. In the mid latitudes, the North Atlantic Oscillation (NAO) is the dominant mode of atmospheric fluctuations over eastern North America, the northern Atlantic Ocean and Europe. Therefore, one of the issues that need to be addressed through data synthesis is the evaluation of interannual patterns in species abundance and species diversity over these regions in regard to the NAO. The database has been used to investigate the ecological role of the NAO in interannual variations of mesozooplankton abundance and biomass along the zonal array of the NAO influence. Basic approach to the proposed research involved: (1) development of co-operation between experts and data holders in Ukraine, Russia, Kazakhstan, Azerbaijan, UK, and USA to rescue and compile the oceanographic data sets and release them on CD-ROM, (2) organization and compilation of a database based on FSU cruises to the above regions, (3) analysis of the basin-scale interannual variability of the zooplankton species abundance, biomass, and species diversity.
Resumo:
We undertook a quantitative study of Thecosomata shells (pelagic gastropods) and their remains in Quaternary foraminiferal oozes deposited on the tilted calcareous platform of the Bougainville Guyot (Hole 831 A), and in the late Quaternary volcanic siltstones, claystones and sandy interbeds on the upper forearc slope of the central New Hebrides Island Arc (Hole 830A). The distribution of the species is based on the identification of adult shells, juvenile stages, protoconchs, and characteristic shell fragments. By studying thecosomatous shells using a scanning electron microscope (SEM), we were able to specify the fine microstructure of the coiled Limacina inflata and compare it with the rod-type crossed-lamellar structure of some other Limacina species, as well as with the helical structure of the Cavoliniidae.