Measuring tissue water potential in marine macroalgae via an updated Chardakov method

Abstract. Regulation of tissue water potential is a key mechanism in macroalgal osmotic responses to changing external conditions, which are common tidally influenced estuarine and intertidal systems. Nevertheless, significant knowledge gaps exist our understanding macroalgae because few methods measure within tissues. Leaf psychrometers have furthered potentials terrestrial plant relations, yet these not been developed the range highly negative values found marine macroalgae. To address gaps, we present an effective, updated version Chardakov method Here, case study examining response by two morphologically evolutionarily distinct species, Ulva lactuca (Chlorophyta) Hypnea musciformis (Rhodophyta) four paired salinity nutrient treatments at temperatures. These simulate gradient from full coastal ocean conditions brackish submarine groundwater discharge, ecosystem type on basaltic shorelines. Both algae demonstrated plasticity discharge with positive correlations between proportion treatment. results first describe potential, step algal physiological ecology such complex environments. This revised valuable tool better understand species-specific ecologically relevant can augment other tidal systems ontogenetic stages.