The potential effects of global climate change on microalgal photosynthesis, growth and ecology

The global environment is currently experiencing a period of significant change in climate as a result of human activities. Although the planet has experienced very significant variations in climate in the geological past, the rate at which the present changes are occurring is extraordinary. Anthropogenic influences have resulted in an enhancement of atmospheric carbon dioxide levels which will amount to a two- to threefold increase over the next century and this has already led to a measurable rise in global temperature. At the same time, chlorofluorocarbons are reacting with ozone in the stratosphere, a process that has led to appreciable enhancement of UV-B radiation (UVBR) fluxes to the earth's surface at high latitudes. This review addresses our present state of knowledge about the effects of enhanced carbon dioxide levels, elevated UVBR fluxes and higher temperatures on the ecophysiology of microalgae. We consider the potential interactions between these and other environmental factors, such as nutrient availability, and also address the ecological consequences of climate change for microalgal assemblages and the flow of materials to higher trophic levels.