PHYSIOLOGICAL ECOLOGY OF THE MARINE ALGA ACROCYSTIS NANA

Abstract

Acrocystis nana is a tropical and subtropical red alga confined to areas of the shore emersed for between 3 and 9 h per tide. In the laboratory, it becomes unhealthy if immersed constantly but retains its original weight if dried for 3 h out of each 24 h and is aerated during the immersion period. Weight loss in various regimes in the light and in the dark is largely confined to material soluble in 0.1 N HC1 and is greatest from an 80% ethanol‐soluble fraction tentatively identified as floridoside. The thalli contain an extracellular sap with an ionic composition distinct from seawater. Results are discussed in relation to the zonation of A. nana on the shore and the concept of physiological buffering. Copyright © 1978, Wiley Blackwell. All rights reserved