The effects of light and temperature on settlement and germination ofEnteromorpha

Abstract
The positive phototactic response of gametes of Enteromorpha is lost on fusion and the zygotes settle in the region of aggregation if a suitable substratum is available, otherwise they sink and settle under gravity. The zygotes and germlings remain viable in total darkness for at least 6 weeks. The first-formed rhizoids are negatively phototropic. The rate of germination of zoospores is more than doubled by a rise in temperature from 10 to 20°C. The relationships of these observations to Enteromorpha as a ship-fouling organism are discussed.