Publication Date:
2022-08-05
Description:
At a longtime station near the "Große Meteor Bank" in the North Atlantic 41 subsequent hauls were made in April 1967 with the Helgoland larva net with changing bucket device. In addition 9 hauls were made during July 1967. The catches from the depth ranges of 900-700 m, 700-500 m, 500-300 m, 300-200 m, 200-100 m, and 100-0 m were collected in separate buckets during each catch series. Contamination, though possible on principle, does not seem to be of much consequence in appendicularia. After some comments on certain species caught (part A, figs. 3-6, table 1, 2) it is shown that at this station in the open ocean the density of appendicularia not only varies with the season, but that clouds of plankton may pass by it within a few hours, in which the density may vary at a ratio of ten or more to one (B, fig. 7, table 7, 8). In the composition of species as many as four species may in turn be the most abundant (C, table 3, 7, 8). For one species the composition as to size and stage of maturity may change in the same way (D, fig. 8, 9, table 4). Regarding the depth distribution there are no species restricted to deeper layers. Below 100 m the number falls to about 1% of the uppermost layer. Oikopleura longicauda, 0. cophocerca, 0. parva and Althoffia tumida as well as Fritillaria species are found between 900 and 100 m in comparatively higher numbers than Stegosoma magnum, Oikopleura albicans and 0. intermedia (E, table 1, 2, 5)
Type:
Article
,
PeerReviewed
Format:
text
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