Channels Galore

The channel experiment has been running in full force for the past two months, and growth in the channels is in full swing.

Pictured: Happy Biofilm!

The channels have been getting lots of visitors recently- the Ring of Fire crew stopped by to conduct metagenomics sampling, which will give us insight into how bacterial communities change over temperature and phosphorus gradients in stream ecosystems. The Ring of Fire is a group of researchers that study geothermal regions in the Arctic to understand how stream ecosystems can act as sentinels for climate change, and we're excited to see the results of this sampling!

We've also begun our main sampling events at the channels for the summer, which include nitrogen fixation, metabolism, and nutrient uptake measurements. These metrics will help us answer the question of how stream biofilms are influenced by increased temperature and phosphorus inputs, and how these biofilm community responses drive processes such as nutrient cycling in aquatic ecosystems. Sampling has been a full group effort, and with everyone's help we've successfully completed the first round of these measurements and are gearing up for the start of the second round of sampling tomorrow. 

The crew admiring their work after a long day

The summer has flown by and the channel experiment only has a few days left, but we'll be busy up until then finishing sampling and enjoying our remaining time in Hengill!

A couple of days ago, Lila got her snail experiment off and rolling...or is that crawling? We're seeing how the phosphorus drip affects how fast snails grow in the different temperature streams. We spent the day finding the smallest snails we could.

Aren't they so cute? Wait you can't see them?

Then we got a picture of each set so we can measure their shell size using image processing software back in the lab.

Ready for their closeup

Then they got settled in their new homes in the streams. We'll let them sit and eat and grow for a few weeks before taking them out for final measurements. 

N Fixation Nation

This week we've been working on nitrogen fixation measurements on the landscape streams. We started it out on Monday (yes, 4th of July) with the full team in the field so we could get everyone trained together.


We've been lucking out on weather lately, so I'm sure it'll downpour next week.

At the moment we're doing acetylene reduction assays (ARA), which involves collecting a primary producer sample and putting it in a chamber with an acetylene-filled balloon.

Get excited about bryophytes, people!

Liesa and Annette prepare party favors acetylene balloons

Then we pop the balloon and shake the chamber to mix the acetylene gas, take an initial gas sample, and let it incubate in the stream for a few hours.

Shaking: not as exciting as bryophytes

Ideal gas sampler:supervisors ratio is 1:5.

This leaves us with plenty of time to relax, contemplate life, nap, or all of the above.

Dr. Dan as The Thinker

Dr. Dan as The Napper

After the incubation is up, it's another shake, another gas sample collection, and then we process the primary producer biomass using highly sophisticated techniques involving kitchen strainers.

Trust me Jill, there were even more unflattering pictures of gas sampling.

Action Packers: BYOTable!

UV or not to UV?

As the days roll past and 15N sampling dates come and go it is easy to forget that the channel experiment stops for no one! Running for almost a month now, the tiles in the experimental channels are beginning to show signs of life. The first biomass sampling of the tiles in our light experiment were collected yesterday and Lyndsie and I spent the day scrubbing tiles in the name of science!

Each channel gets one piece of UV blocking and one piece of transparent plastic, alternating which is up and down stream.

The warmer channels are starting to fill up with all sorts of biomass while the cooler temperature channels show little colonization.

Lyndsie is always hard at work and decided to check the temperatures under our UV plastic to see if they are acting like little green houses facilitating more growth. Good thinkin'!