Acclimation responses to salinity of three estuarine red algae from New Jersey

Abstract

The effects of salinity and acclimation time on the net photosynthetic responses of 3 estuarine red algae, Bostrychia radicans Mont., Caloglossa leprieurii (Mont.) J. Ag., and Polysiphonia subtilissima Mont., from Great Bay Estuary, New Jersey, USA, were investigated. The algae were cultured in a series of synthetic seawater media of 5, 15, 25 and 35% S for acclimation periods of 0, 2, 4, 8, and 16 days prior to determining their photosynthetic responses. All species were euryhaline, and demonstrated photosynthesis at all the above salinities. B. radicans, which was more common towards the mouth of the estuary, had a maximum photosynthetic rate at 25% S, whilst C. leprieurii and P. subtilissima, which were more common towards the head of the estuary, had photosynthetic maxima between 15 and 25%, and at 15%, respectively. The curves relating net photosynthesis to salinity were usually similar within a species at different acclimation periods, although statistically significant differences were sometimes noted. The acclimation periods producing maximal net photosynthesis were 0, 2 and 4 days for B. radicans, and 4 days for C. leprieurii, whilst for P. subtilissima there was no significant difference in response for any acclimation period over the range of salinities studied.