The green slime: genomics researchers do battle with summer spoiler


- Ottawa, Ontario

Harmful algal blooms (HABs): the bright, blue-green layer of scum we often see floating on or just below the surface of lakes and rivers in the summer months. While they discourage swimming and other recreation, the blooms—actually caused by cyanobacteria—can be much more than simply unappetizing.

As Dr. Charles Greer at the National Research Council of Canada (NRC) points out, while some varieties of the cyanobacteria that form the blooms are harmless, many others can produce dangerous toxins. "We've seen many deaths of livestock and other animals that have consumed water contaminated by these toxic blooms," says Dr. Greer. "The biggest concern is the potential for these toxins to get into the drinking water supply."

Predict, perhaps prevent

As part of the Ecobiomics Project—a 5-year, multi-department research collaboration funded through the Government of Canada's Genomics Research and Development Initiative (GRDI)—Dr. Greer, a Principal Researcher with the NRC's Energy, Mining and Environment Research Centre in Montreal, is working with Environment and Climate Change Canada (ECCC) Research Scientist Dr. Sophie Crevecoeur in using advanced genomics technologies to understand how and when toxic algal blooms occur.

"With that understanding," says Dr. Greer, "We may be able to predict when they will occur and thus limit their potential impact and possibly even prevent them from happening in the first place."


Don't go near the water: bright blue-green slime of harmful algal bloom (cyanobacteria) can be toxic. (photo: Charles Greer, NRC)

The food factor

Both researchers make the point that cyanobacteria are found almost everywhere and might not ordinarily be a concern if we didn't feed them. "Most cyanobacteria need nitrogen and phosphorus to grow," says Dr. Greer. "We are looking at how land-use disturbances such as agriculture, urbanization, forestry and mining could be adding these nutrients to the waterways."

While the availability of nutrients would seem to be part of the problem, Dr. Crevecoeur, speaking from ECCC's Canada Centre for Inland Water in Burlington, Ontario, says other mechanisms could play a part in triggering toxic blooms.

"Certainly, algal blooms in Lake Erie declined for a number of years after a joint Canada-U.S. effort to reduce phosphorus run-off into the lake launched in the 1970s," says Dr. Crevecoeur. "But they started to increase again in the 1990s and some of the biggest in decades have happened in the last few years."

Seeking out the microbial origins

Using DNA analysis, Dr. Crevecoeur, Dr. Greer and their team are looking at the microbial communities found in the lake, in upstream waterways, and in the surrounding soil to determine where the cyanobacteria responsible for toxic blooms are coming from, and how different microorganisms may be interacting with cyanobacteria to support their growth and toxicity.

"Cyanobacteria are everywhere, so we are looking for the connections," says Dr. Crevecoeur. "By looking at the DNA of the cyanobacteria in the soil near waterways, we can see if it's the same or closely related to the cyanobacteria blooming in the lake. By looking at samples taken from riverbeds, we can see how the cyanobacterial community may change as it travels downstream, and how other microorganisms may be involved in those changes—including the part other members of the microbial community may play in making nutrients more available to the cyanobacteria."


Harmful algal blooms can grow to cover wide expanses of water. (photo: Charles Greer, NRC)

Praise for GRDI

Both say their research would not be possible without the collaboration that characterizes the GRDI Ecobiomics Project, which involves dozens of scientists from 7 federal departments and agencies working on 16 different but related research projects.

"As part of the Ecobiomics Project, we have access to resources and data that we would never have been able to acquire on our own," says Dr. Crevecoeur. "That ranges from DNA sequencing equipment to data on microbial communities in soil generated by Agriculture and Agri-Food Canada researchers working on another part of the Ecobiomics Project."

Equally important, says Dr. Greer, is that the same protocols and technologies for collecting and conducting the genomic analysis of samples are used throughout the Ecobiomics Project. "That means we can add data from water sampling done by someone at Fisheries and Oceans Canada to our study, knowing we'd get the same result if we tested it ourselves," says Dr. Greer. "Basically, GRDI is enabling us to do more science in less time and for a lot less money."