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SPECIFIC GRAVITY AS A FACTOR IN THE VERTICAL DISTRIBUTION OF PLANKTON
Author(s) -
EYDEN DORA
Publication year - 1923
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/j.1469-185x.1923.tb00531.x
Subject(s) - daphnia pulex , sunrise , plankton , brood , ecology , oceanography , biology , environmental science , geology , atmospheric sciences , zooplankton , daphnia
Summary. (1) It is established that the specific gravity of Daphne pulex varies. The state of starvation of the animal, and the number of young in the brood pouch, separately affect the specific gravity. (2) The release of the young from the brood pouch causes an instantaneous decrease of specific gravity. (3) The specific gravity varies in animals of the same size at different periods of the day and night, attaining a maximum shortly after sunrise, and reaching a less well‐defined minimum about midday. (4) D. pulex is most abundant in shallow water shortly before sunrise, and most scarce from midnight till just before dawn, and when the sun is shining directly on the water. (5) Changes in specific gravity must be taken into consideration when investigating the causes of the vertical distribution of the plankton.