Most of us learned at a young age that everything in nature is connected.

We also might’ve learned that matter, especially carbon, plays an essential role in aquatic ecosystems.

For instance, carbon in specific forms, helps regulate a lake’s acidity or alkalinity by adjusting its pH. Without having carbon ions to help regulate the water’s pH, some fish species can die.

Trent University student, Sohidul Islam, moved from Bangladesh to Peterborough and is completing his PhD in Environmental Life Sciences and is looking at a particular type of carbon.

He is studying dissolved organic matter (DOM), which is known as the fingerprint or DNA of an aquatic region because it is unique in every area.

DOM is a heterogeneous (like a tea or soup that has different components) mixture of organic compounds, sourced from land and microorganisms. It has variable chemical properties and reactivity.

DOM is important because it can be used as a tracer in the environment to help determine the effects of climate change in certain areas.

Because of melting ice and thawing permafrost in the arctic, levels of DOM increase or decrease, depending on the area. Fluctuating levels of DOM can be used by scientists to indicate and predict stress levels of aquatic ecosystems.

It is known that less DOM in a lake can make the lake much lighter in colour overall, allowing light to penetrate deeper into the lake.

This makes the warm water layer on the surface of the lake deeper.

Fish that love cold water, like trout, are forced into smaller areas at the bottom of lakes – where oxygen levels are poor. For aquatic life, spending time in water that is either low in oxygen or too warm can have a negative impact on their health.

Solar/light exposure plays a significant role in DOM – but there are many unanswered questions, that Sohidul is trying to answer.

He is studying the Hudson Bay because it receives large amounts of DOM from more than 42 rivers and the surrounding areas and the topic hasn’t been given much research attention.

Sohidul studied DOM solar/light exposure and how it can play a significant role in aquatic health. To collect DOM, he used various samples like lab culture algae samples, permafrost soils, and mixed samples (Churchill River, and Hudson Bay Coastal waters: Chesterfield Inlet, Nelson River mouth, Winisk River mouth and James Bay).  

Sohidul applied different techniques to see how light/solar exposure would change the composition, size and color (optical properties) of water samples collected from different sources and seasons in the Hudson Bay watershed.

He found that solar/light exposure showed profound changes in the colour of the lake – making it either lighter or darker. In addition, Sohidul found that the properties and composition of DOM collected from different sources in Hudson Bay and could potentially produce CO and CO2 in the environment.

DOM can significantly alter marine environments and should be monitored. It can help indicate that climate change is having an effect on specific areas and helps scientists monitor stress levels of water bodies.

Thank you to Sohidul for sharing your important research with us about dissolved organic matter and how it can play a part in monitoring marine health in the Hudson Bay area and showing the effects of climate change.

An overview of Sohidul’s research

Here is what Sohidul had to say about his experience at Trent University:

“I like the natural environment at Trent University. I am fortunate to have a very supportive supervisor. The lab is well equipped for environmental studies. Other professors I have met have been approachable and helpful. My lab group is a next home environment while I am thousands of miles away from home.”