Freshwater database helps researchers around the world

As the world comes to grips with the global implications of climate change, a key focus will be the freshwater found in the world’s lakes.  

Lake water accounts for less than one percent of the world’s surface freshwater supply, but provides critical ecosystem services including consumption, transportation, agriculture and recreation, in addition to habitat for more than 100,000 species of invertebrates, insects, animals and plants. However, freshwater lakes are vulnerable to the effects of water fouling, nutrient enrichment, and alterations in climate and land use, owing to their sensitivity to local and global environmental changes. 

To meet this challenge, York University researchers working in the lab of associate biology professor Sapna Sharma have created a publicly available water quality database of approximately 12,000 freshwater lakes around the world that will help scientists monitor and manage the health of these and other lakes. The study has collected data from 72 countries, including hundreds of lakes in Canada, and is an example of innovative research that is already having a wide-ranging, positive impact on communities around the world. 

“The creation of this database is a feat typically only accomplished by very large teams with millions of dollars, not by a single lab with a few small grants, which is why I am especially proud of this research,” says Sharma. 

Researchers have reviewed 3,322 studies from as far back as the 1950s along with online data repositories to collect information on chlorophyll levels, a commonly used marker to determine lake and ecosystem health. Chlorophyll is a predictor of the amount of vegetation and algae in lakes, known as primary production. According to Sharma, warming summer temperatures and increased solar radiation from decreased cloud cover contribute to an increase in chlorophyll, while more storm events caused by climate change contribute to degraded water quality. 

“Human activity, climate warming, agricultural and urban runoff and phosphorus from land use can all increase the level of chlorophyll in lakes,” says postdoctoral fellow Alessandro Filazzola, one of the study’s leaders. “Primary production is most represented by the amount of chlorophyll in the lake, which has a cascading impact… If the chlorophyll is too low, it can have cascading negative effects on the entire ecosystem, while too much can cause an abundance of algae growth, which is not always good.” 

Sharma says the database can be used to improve our understanding of how chlorophyll levels respond to global environmental change. “It provides baseline comparisons for environmental managers responsible for maintaining water quality and the overall health of our lakes and the communities they support.”