BIOLOGICAL PRODUCTIVITY PROJECT.
Abstract
Several studies on natural populations in Narragansett Bay, R. I., were completed: The growth of Venus mercenaria was shown to be positively correlated with water temperatures between 10 and 23C, and with the abundance of small diatoms, and inversely related to the silt-clay content of the sediment. Two sources of error in the oxygen method for measuring primary production were identified and measured: bacterial respiration, and changes in the enclosed phytoplankton population. Mortality rates of Escherichia coli were especially high when cultured in water taken from the Bay during the terminal phase of Skeletonema costatum blooms. Studies of the spectral sensitivity and depth distribution of Neomysis americana showed that this animal has a strong preference for blue-green light, its diurnal vertical magration is controlled by light intensity, and the dawn rise (which occurs only during the short-night months) is inhibited during the long-night months because the animals become dark adapted. Seasonal changes in the abundance and species composition of the Bay phytoplankton and zooplankton are described. The winter-spring diatom flowering lasts from January to May. Its inception is triggered by the release of zooplankton grazing pressure, and its magnitude is regulated by the concentrations of nitrate and silicate at the beginning of logarithmic growth. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1966
- Accession Number
- AD0635140
Entities
People
- David M. Pratt