DURING an investigation of the blood system in polychaetes of the families Serpulidae and Sabellidae the musculature of the alimentary canal has been studied. In the following species the only muscle coat, which consists of fibres lying transverse to the main axis, lies outside the blood sinus which envelops the canal: Serpula vermicularis L., Hydroides norvegica (Gunnerus), Vermiliopsis infund...

Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the ...

The feeding habits of 4 species of Plesionika inhabiting the Alboran Sea (SW Mediterranean) at depths between 29 and 790 m were analyzed. Included within the trophic guild of nonmigratory macroplankton feeders, Plesionika spp. preferably exploited mesopelagic resources (mainly euphausiids and Myctophidae). Deep-bathyal species (P. martia, P. gigliolii and P. edwardsi) fitted better within this ...

A 50-yr study at Fairbanks, AK, was started in 1984 to determine soil seed longevity of 17 weed species. Seeds were buried in mesh bags 2and 15-cm deep and were recovered 0.7, 1.7, 2.7, 3.7, 4.7, 6.7, 9.7, 19.7, and 24.7 yr later. Viability was determined using germination and tetrazolium tests. By 24.7 yr after burial (YAB), no viable seeds were found for common hempnettle, flixweed, foxtail b...

The effect of foraging behavior on predation risk was studied by exposing the two small Calanoid copepods Acartia clausi and Acartia tonsa to 0 or 1 ppm (1,500 cells ml-l) of the diatom Thalassiosira weissfogii and to presence of the predator Pureuchaeta norvegica. In filtered water, predation rate was the same on the two species. In algal suspension, predation rate on A. clausi was half that i...