Ecosystem services of Earth's largest freshwater lakes

Fresh water is distributed unevenly across the globe. Earth's 21 largest lakes hold similar to 2/3 of all global, liquid, surface, fresh water and occupy diverse ecological and social settings. We identified seven ecosystem services for which there were quantitative data across most or all of these large lakes. Approximately 1.35 million tonnes of fish are harvested per year from these lakes by commercial or artisanal means, with approximately 95% of this harvest coming from the African large lakes. The 21 lakes support the generation of at least 62.2 GW of power and the transportation of 195 million tonnes/year of cargo, with the Laurentian Great Lakes especially important in those. More than five billion m(3) of potable drinking water is treated annually from large lakes, and an additional 812 million m(3) water per year is extracted for irrigation purposes. The pattern of services provided to humans by large lakes differs based on social and environmental settings. While we assembled systematic data on some important ecosystem services from large lakes, many other important, especially non-commercial services could not similarly be examined due to lack of data. More work is needed to show the value of the full set of ecosystem services provided by large lakes.