Monitoring the condition of lakes through microorganisms living in them

A lake is more than just a body of water where we bask on bright summer days. It is also more than just a source of fresh water surrounded by nature and peace.

Lakes play a role plays a key role in our ecosystems and in our daily lives. They provide drinking water, are home to an impressive diversity of life forms, and support critical economic activities.

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This article is part of our series Our Lakes: Their Secrets and Challenges. This summer, The Conversation and La Conversation invite you to a fascinating swim in our lakes. Our scientists, using magnifying glasses, microscopes and diving goggles, explore the biodiversity of our lakes and the processes that take place in them, and tell us about the challenges they face. Don’t miss our articles on these incredibly opulent water bodies!

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Unfortunately, the water quality in these valuable environments is increasingly at risk by various environmental factors and human activities.

To protect and preserve lakes, it is necessary to monitor their health proactively, quickly, and effectively. As aquatic ecology researchers, we had this in mind when we developed a novel, cutting-edge technology to measure lake health by monitoring the microorganisms living in them.

Our planet and its ecosystems in transition

Our planet is constantly changing and its ecosystems are feeling the effects.

Lakes in particular are influenced by many factors: industrial and agricultural pollution, road salt, Eutrophication AND rising temperatures due to climate change.

They contribute to the deterioration of water quality and disturb the balance of aquatic ecosystems.

For example, the proliferation of cyanobacteria or algae cyanobacteriaposes a stern threat to human health and the environment. Although microscopic, cyanobacteria can form evident proliferations, known as blooms, as they multiply and clump together.

Some species of cyanobacteria responsible for blooms produce toxins (cyanotoxins) that can contaminate drinking water.harm aquatic life and lead to beach closures. Algal blooms can also threaten recreation and tourism, and local economies.

Unfortunately, with global warming, The proliferation of cyanobacteria in our lakes is expected to continue to increase.

Microbiome: An Indicator of Lake Health

One drop of lake water can be home to thousands, even hundreds of thousands, of microbes.

These microbes make up the lake’s microbiome, which is a key indicator of its health. In other words, if something is wrong with the lake, these microbes will be the first to reveal the problem.

It’s a bit like your digestive system isn’t working due to an imbalance in your gut microbiome.

Microbes, though microscopic, are the noiseless guardians of our aquatic ecosystems. Accessing this front line of information is therefore necessary to understanding the health of our lakes and any changes that are occurring in them.

How can we obtain this valuable information quickly and efficiently?

Genomic Tools: Next Generation Ecosystem Monitoring

This is where up-to-date sequencing tools come in. Environmental DNAor eDNA, a mixture of the genetic material of organisms inhabiting a given environment.

For example, metagenomics gives us access to each person’s DNA sequences, called genomes, of all the microbes in a water sample. This tool provides a complete picture of the composition of a lake’s microbiome, including species that are harder to detect.

Optical microscopy, traditionally used to monitor cyanobacteria, can magnify organisms by up to a thousand times, making them easier to visualize and count. While effective, the technique still requires a significant investment of time and relies on visual identification of species by expert taxonomists. Moreover, unlike sequencing tools, it cannot detect microbes that are too compact.

The eDNA sequencing approach can therefore be used as a complement to optical microscopy to reduce potential identification errors. It also has the advantage that it can be used directly in the field. Fresh generations of sequencing equipment can be transported to the field and can provide a microbiome profile within hours.

Using sequencing techniques, we can quickly detect changes in the microbial community that indicate environmental imbalance. For example, a sudden enhance in cyanobacteria can be seen before the effects are evident, such as flowersappear. These advanced tools enable environmental managers to take preventive measures earlier.

RosHAB Innovation

Among the recent innovations in sequencing, RosHAB The tool developed by our team at the Institut national de la recherche scientifique in collaboration with scientists from Université Laval stands out for its ability to describe the genome of lake microorganisms in real time.

This advanced tool uses metagenomics to monitor microbial diversity and detect potential imbalances. Designed for apply by environmental managers, RosHAB is a practical and rapid method for continuous monitoring of aquatic ecosystems, directly in the field.

Practical implications and limitations

To integrate genomic tools into lake and water ecosystem management policies, it is necessary to train and adapt monitoring teams.

While these technologies offer many advantages, they also pose a number of challenges. First, bioinformatics analysis is not straightforward and must be accessible to nonexperts.

In addition, data analysis can be complicated by changes in microbial diversity from season to season. Regular monthly or even more constant sampling is necessary to obtain representative results.

Monitoring the condition of lakes is crucial in the face of growing threats from climate change and human activity.

Lakes are critical ecosystems, and their protection requires advanced, proactive monitoring methods. Genomic tools such as RosHAB represent a significant advance in this field, offering an effective means of predicting and responding to environmental threats.

By understanding and monitoring the health of lakes through the microorganisms that live in them, we can better protect these resources so that future generations can enjoy them as much as we do on scorching summer days.