Climate change is increasing lake surface temperatures across the world. The problem is that until now the change has only been understood through satellite observations.
Increases in lake temperatures could have significant implications for ecology. According to the Union of Concerned Scientists, warming lakes can form ‘dead’ zones’ – oxygen-starved areas susceptible to toxic algae blooms. Cold-water species can also be displaced from a lake.
Other potential impacts include greater stress on species due to changes in season and an increase in disease.
Researchers from York University in Toronto have monitored the increase in lake temperatures by constructing a database stretching back to 1985.
‘There has been a significant need to put together a database like this, considering the rapid warming of lakes,’ says Professor Sapna Sharma, who led the international effort.
The database includes 291 lakes and reservoirs across the world with summer-mean temperatures collected up to 2009.
‘Previously there were only satellite collected data available globally and we have doubled the data through in situ programs such as the Global Lake Ecological Observatory Network and long-term monitoring programs, which collect data from visiting these locations,’ Sharma adds.
‘Unfortunately satellites are generally restricted to observing lakes greater than 10,000 ha and so miss out on 90 per cent of the world’s lakes that are smaller and shallower,’ she told Geographical.
Over 20 countries contributed to the four-year effort, with samples gathered from every continent.
‘Our plan is to include additional lakes, longer time periods, and vertical temperature profile data,’ adds Sharma.