Primary production of macrophytic algae in three supralittoral rock pools on the Atlantic coast of Nova Scotia

Estimates of net primary production of macrophytic algae for July and August were made for three rock pools in the supralittoral zone at Finck Cove, Halifax County. Net primary production was estimated from diurnal changes in oxygen concentrations. Values for July and August varied among pools from 3.4 to 35.9 mg C•dm⁻². Variations in rates within each pool also occurred. These variations were attributed to changes in algal species composition and biomass in the pools. Measurements of algal photosynthetic rates were used to estimate net primary production. The estimates using this method were higher than those obtained from diurnal changes in oxygen concentrations. Temperature, pH, salinity, and oxygen concentrations were monitored in the pools for 24 h periods. Distinct diurnal and seasonal fluctuations were observed for temperature, pH and oxygen. Salinity did not show this type of variation. The ecological implications of these fluctuations are discussed.