Patchiness in the distribution of planktonic foraminifera

• Main Author: Boltovskoy, Esteban
• Format: Book Part
• Language: English
• Published: Ed. Tecnoscienza 1971
• Subjects: Planktonic foraminifera; South Atlantic Ocean
• Online Access: https://oceanrep.geomar.de/id/eprint/34598/; https://oceanrep.geomar.de/id/eprint/34598/1/scan_2016-11-07_13-26-21r.1.pdf

Three hundred plankton samples were taken in the South Atlantic Ocean by means of a fire pump along six straight line series. Five minutes elapsed during the pumping of each sample. During this time the ship covered 0.83 nautical miles. Intervals between the collection of adjacent samples were equal approximately to a minute, during which time the ship covered 0.17 nautical miles. The volume of water filtered for each sample was c. 3.220 litres, and each series covered a distance of 50 miles. Planktonic Foraminifera in the samples were picked out, studied, and counted. A well pronounced patchiness in distribution was observed for all the species composing the assemblages, especially in the areas which are rich quantitatively. The greatest sudden quantitative change was observed in series V where at two nearby stations 198.2 and 2.2 specimens per cubic meter of filtered water were observed. In other words, within a distance of one nautical mile the foraminiferal number decreased by a factor of 90. Such a great difference indicates that the results of studies of numerical abundance based on a few samples cannot be considered reliable. The poorest area was crossed by series H, and the differences between foraminiferal numbers observed at neighboring stations along this series were the smallest.