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Ecological Studies on the Planktonic Protozoa of a Small Artificial Pond 1
Author(s) -
BAMFORTH STUART S.
Publication year - 1958
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1958.3.4.0398
Subject(s) - plankton , phytoplankton , phosphate , nutrient , turbidity , environmental chemistry , population , protozoa , alkalinity , nitrate , euglena , biology , environmental science , ecology , botany , chemistry , chloroplast , biochemistry , demography , organic chemistry , gene , sociology
A one‐year survey was conducted on a small artificial pond to determine environmental relationships of planktonic protozoa to physical and inorganic chemical factors. Collections were made at 9:00 A. M., Eastern Standard Time, every other day. Planktonic samples were taken from the surface and bottom, and sunlight intensity and temperature were measured. Chemical analyses included alkalinity, carbon dioxide, chloride, dissolved oxygen, nitrate, nitrite, ammonia, phosphate, pH, hardness, and turbidity. Bacteria counts were made microscopically, and protozoa were handled by the Sedgwick‐Rafter method. The order of appearance of phytoplankton may have been influenced by the abundance of growth factors coupled with varying amounts of dissolved substances: Cryptomonas appeared in autumn and early summer; chrysomonads and Chlamydomonas in winter; Glenodinium, Pyramimonas , and diatoms in spring; and euglenoids in summer. The amount of phosphate seemed to influence which phytoplankters appeared: chrysomonads were not found when the water contained more than 0.02 ppm of phosphate, whereas cryptomonads and diatoms increased at this concentration, and euglenoids were abundant at several times this concentration. Within each phosphate range other factors, such as nitrogen sources and growth factors, exercised more immediate effects. Supply of organic nutrients appeared to influence euglenoid numbers. Increases in sunlight and temperature were favorable for diatoms but unfavorable for Glenodinium cinctum and Trachelomonas hispida. The nature and amount of food appeared to be the controlling factor for ciliates. Many plankters live perilously close to minimum survival conditions, and slight environmental changes can promote rapid growth, reduction, or subsidence of a population. This survey shows that detailed studies are necessary to ascertain ecological relationships of microorganisms, and that protozoan habitats must be defined more precisely.