. Calanoid copepods of the genera Spinocalanus and Mimocalanus from the central Arctic Ocean, with a review of the Spinocalanidae / David M. Damkaer. Copepoda Arctic Their absence from surface-layer samples, however, indirectly fixes their upper depth limit, generally at about 100 m. Spinocalanids have been collected in a lesser number of deep closing-net samples taken at discrete depths. A lower depth limit, if there is such a limit, has not been fixed; some species have an ex- traordinary vertical distribution, from 50 m to at least 5,000 m. The great vertical range gives these speci
. Calanoid copepods of the genera Spinocalanus and Mimocalanus from the central Arctic Ocean, with a review of the Spinocalanidae / David M. Damkaer. Copepoda Arctic Their absence from surface-layer samples, however, indirectly fixes their upper depth limit, generally at about 100 m. Spinocalanids have been collected in a lesser number of deep closing-net samples taken at discrete depths. A lower depth limit, if there is such a limit, has not been fixed; some species have an ex- traordinary vertical distribution, from 50 m to at least 5,000 m. The great vertical range gives these species a potential for wide, in some cases worldwide, distribu- tion in the relatively uniform and interconnected deep-ocean water masses. The lack of records for some species from entire oceans cannot yet be accepted as an indication of real absence. In particular, the ap- parent bipolar distribution of Spinocalanus antarc- ticus should be reconsidered, to determine its dis- tribution into lower latitudes. In the decades since World War II interest in the Arctic Ocean has greatly increased, for commercial, strategic, and scientific reasons. The heroic days of the earliest Arctic explorations, when observations were gained under the harshest conditions, are past. In spite of the difficult and distant environment, in- formation now accumulates relatively rapidly. The development of air transportation and the use of floating ice platforms have made all Arctic areas accessible throughout the year. Still, most subjects of investigation remain in an exploratory stage; this is especially true of the oceanic plankton of the high polar basins. The oceanic copepods, the most numerous of the net-zooplankton, are the subject of less than a dozen published reports, and only three or four of these consider deepwater species. The present study is based on collections of zooplankton from Fletcher's Ice Island, in the Canadian Basin in 1967- 68. The spinocalanids from these collections are redescr
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