| Abstrakt: |
Abstract: This paper deals with studies on temperature, salinity, turbidity, phosphate, silicate, nitrate, chlorophylla and zooplankton in the Patuxent River Estuary for a 20-month period from July 1963 to February 1965. Temperatures ranged from less than 1 C to higher than 30 C; salinities ranged from 0.1 to 19.2% and showed higher values than earlier reported investigations. Turbidities ranged from 0 to 113 ppm and decreased downstream. Phosphates ranged from 0 to 2.1ug at/L and showed no marked seasonal or distributional patterns. Silicates decreased slightly downstream from a maximum of 135ug at/L at the uppermost station. Nitrates ranged from 0 to 14.5ug/L with an early spring maximum and highest values occurred at upstream stations. Chlorophylla determinations showed minimal winter and maximal spring and summer values; a spring chlorophylla peak closely followed a spring NO3 maximum. Zooplankton, sampled with a No. 2 net, showed lowest standing crops during summer and early fall (less than 100/m3) and highest during winter and early spring (greater than 7000/m3). By number, copepods comprised 98.1% of total zooplankton (excluding ctenophores and coelenterates). The major components of the zooplankton wereAcartia tonsa, A. clausii, andEurytemora affinis. Eurytemora dominated upriver in lower salinities, andA. tonsa dominated downriver in higher salinities except during March and April, when it was replaced byA. clausii. |
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