Friday, August 12, 2016

Testing hypotheses in artificial streams

Ella has been able to collect detailed data on gas emissions from 13 hippo pools, in addition to the 12 hippo pools we sampled last year. This will give her a nice range of hippo density and river flow level in order to test how these two factors influence gas emission levels. However, all the variability often present in the field can often make it difficult to accurately determine the influence of various factors, so Ella designed an experiment in the artificial streams to test her hypotheses more directly.

She added blackwater from the bottom of a very concentrated hippo pool to the artificial streams in varying concentrations.

Ella adding black water to the artificial streams
Then she ran the streams at different velocities.

Ella's artificial stream experiment
At various time points, she collected water samples from each stream and collected dissolved gases from each sample into vials which will be analyzed back at the Cary Institute. Actually, we had a team of 4 people working as fast as possible every 45 minutes throughout a whole day to collect the water samples at specific times. Again, we were lucky to have a great team!

Ella collecting a gas sample
We couldn't analyze any of the gas data in the field, so we won't know the results of this experiment until the fall, but all of the dissolved oxygen data from the streams suggest we were successful in capturing the range of conditions we were hoping for. Can't wait to see how all of this comes together!
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