Universe Today
The study - "Dependence of Biological Activity on the Surface Water Fraction of Planets", which is being reviewed for publication with The Astronomical Journal- was authored by Manasvi Lingam, a postdoctoral fellow with the CfA's Institute for Theory and Computation (ITC), and Abraham Loeb - the director of the ITC and the Frank B. Baird Jr. Chair of Science at Harvard University.
"The fact that the Earth's land and water fractions are comparable is indicative of anthropic selection effects, that is to say, the emergence of humans (or analogous conscious observers) may have been facilitated by a suitable mixture of land and water."
"[W]e developed a simple model to estimate what fraction of the land will be arid (i.e. deserts) and relatively uninhabitable. For the scenario with water-dominated biospheres, the availability of phosphorus becomes the limiting factor. Here, we utilized a model developed in one of our earlier papers that takes into account the sources and sinks of phosphorus. We combined these two cases, used data from Earth as the benchmark, and thus determined how the properties of a generic biosphere would depend on the amount of land and water."
"Thus, the basic conclusion is that the balance of land and water fractions cannot be tilted too much one way or another. Our work also shows that important evolutionary events, such as the rise in oxygen levels and the emergence of technological species, may be affected by the land-water fraction, and that the optimal value could be close to that of the Earth."
