Integrated responses to salinity fluctuation

Abstract

SYNOPSIS. Continuous and discontinuous intertidal waters both experience fluctuations in salinity frequently accompanied by changes in temperature, levels of dissolved gases and pH. A multidimensional approach to environmental fitness may therefore be more representative of natural conditions in the intertidal zone. Various combinations of environmental factors are discussed including salinity/temperature, and salinity/O2 tension. Salinity will directly affect osmotic and ionic regulation and indirectly affect acid-base balance and various components of the respiratory system including ventilation, gas exchange, perfusion, O2 transport by the respiratory pigment and utilization at the tissues. Additional areas covered in this review article are osmotic problems faced by air-breathing aquatic intertidal animals, ontogenetic changes in osmoregulatory capabilities and a comparison of steady state (square wave) versus sinusoidal (cyclical) salinity changes. © 1988 by the American Society of Zoologists.