The 7th International CO2 Conference Web Site - The Role of Water Relations in Driving Grassland Ecosystem Responses to Rising A

by Jack Morgan

While rising atmospheric carbon dioxide (CO₂) is known to be an important contributor to radiative forcing of Earth’s climate, more direct effects of this gas on photosynthesis and plant water relations have been underway for more than a century, and likely have already contributed to important ecosystem changes. Experiments conducted in native and semi-natural grasslands in which ambient CO₂ concentrations have been artificially increased have shown that increasing CO₂ often increases photosynthesis, results in higher soil and plant water content, and can enhance plant water use efficiency, the ratio of plant biomass produced per unit water transpired back to the atmosphere. While these responses may appear beneficial, there are long-term responses of ecosystems to CO₂ such as alterations in the cycling and availability of critical plant nutrients like nitrogen (N) which are likely to change over time and may significantly alter CO₂-enhanced production and forage quality. Herein we discuss these phenomena and speculate on the implications and the importance for world grasslands.

Link to Abstract
Link to Slides