For Some Researchers, The Most Interesting Thing in a Lake Is What They Can’t See

I have to admit, when I first learned Adam Rexroade, a master’s student at Trout Lake Station, was studying methane emissions in a nearby stream, the project didn’t sound very interesting. If he were studying a specific plant or animal, I’d be ready to go. Streams have a lot of life in and around them and Adam is sampling both day and night this summer, which is an unusual field work schedule.

But, methane? It just didn’t click for me. Even Adam’s favorite thing about his work this summer has little to do with methane.

“It is amazing to me how different the same site looks over the course of 24 hours,” he told me. “You see and hear different animals, it smells different at night than during the day, and you see the moon and stars instead of only the sun. Everything is covered in dew in the morning, and you can see all of the spider webs built over the night. I thought I knew the field site before I did night sampling, but the truth is it looks so different depending on the time you are there.”

Adam at night in the canoe. Photo: Cassie Gauthier.

So, why is Adam spending his time studying a smelly natural gas? And what relevance does it have to the life of a stream?

Luckily, I put my methane skepticism aside and spent some time with Adam out at his research site on Allequash Creek. It turns out that there are a lot of things happening beyond what we can observe with our senses in streams and other bodies of water – and just because we can’t see them doesn’t mean that they aren’t urgent to be thinking about.

Methane is a potent greenhouse gas that is contributing to global warming. And it usually makes me think of factory farms, natural gas, and ways it gets into the atmosphere. What I didn’t know was that human development around lakes and streams is contributing to the increase of methane emissions across the world.

Methane emissions from lakes have been well monitored by scientists. Streams, however, are a less familiar venue. Adam’s goal this summer, along with the help of undergraduate J Sturim, is to find out how much methane is released into the air in a 24-hour period from Allequash Creek, a stream ecosystem only a few minutes from Trout Lake Station. His hope is that by spending time monitoring the creek, he will contribute to a broader understanding of where methane is coming from and where it is going, which will help us better understand ways to reduce methane emissions.

Methane is released into the atmosphere in three ways: it is diffused from the water’s surface, emitted by plants as they “exhale” or release waste gases from the stomata in their leaves, or methane can bubble up from the bottom sediments of a stream.
Adam and J are measuring each of the three methane pathways and “hope to determine which contributes to the most methane release,” Adam says.

Adam changes out the battery and SIM card in one of the bubble sensors. Photo: Cassie Gauthier

To measure how much methane is evaporating off of the water’s surface, Adam places a bucket upside down on top of the water. A tube at the top of this contraption connects to a sensor that is able to detect the amount of methane flowing up off the water’s surface and into the bucket. A similar process is used to measure how much methane plants give off; only the bucket is put directly over the plants.

To collect data about how much methane the bubbles release Adam and J have placed ten sensors throughout the middle of the stream that will stay there all summer. These sensors have an upside-down funnel under the water that is able to capture the bubbles and then determine how much methane is in them. Once installed, all Adam and J need to do is periodically replace the batteries and the SD memory cards that record their data. Then they just need to wait. Hopefully, by the end of the summer, they’ll have enough data to declare one form of methane production the “winner.”

“This has been my first real experience doing fieldwork outside of the classroom,” says J. “I have loved applying what I have learned in classes to a real-life system and learning new information about something no one has ever studied before. To me that is almost more exciting than knowing the exact results.”

While scientists are still learning the full picture of what causes aquatic ecosystems to produce methane, there is evidence that fertilizer and other chemical runoff plays a role.

Making sure the shorelines of lakes and streams have buffers with natural plants and supporting farms that use best practices for reducing runoff and minimize fertilizer and pesticide use are two simple ways your actions can help reduce harmful runoffs. It is our job as people who love lakes, streams, and all the beauty within them to take care of them and keep them around. And I think it is safe to say that both Adam and J are doing their part this summer by studying methane – the less obvious – but equally important – part of stream ecosystems.

J ready to sample and about to get into her canoe. Photo: Cassie Gauthier.