Wednesday, January 6, 2010

Stoichiometry Sampling... a Little Late!

We finally got a small enough window in the bad weather for me to get out to the field yesterday. Now I'm back at Lake Fryxell. The work that needs to be done right now is the annual treatment of our Stoichiometry Plots. These are for a long-term experiment that has been going on for several years. We hypothesize that, if the climate warms, there will be more liquid water. With that liquid water comes more nutrients in the soil. We want to know how the soil organisms respond to that nutrient and water pulses to influence nutrient cycling so that we can predict how climate change might influence the soils. So, we are adding water and nutrients to simulate this type of change. Every year we add more nutrients and every two years we take soil samples to measure the response.

To add the treatments to the plots, we have to bring a LOT of water to the field: 775 pounds of water! That means we need a lot of team members to help us carry the carboys of water solutions. Because we've had so much bad weather, our team has had to split up a lot, so only 3 of us were being sent to Fryxell to do all of the work sampling and treating the plots. It is myself, Bishwo from Brigham Young, and Zach from Colorado State. Unfortunately, the weather went sour just about as soon as I landed, so Bishwo and Zach couldn't make it to join me! I did all of the soil sampling by myself, so that the samples could be sent back to the lab for processing. They had to wait overnight, because no helicopter could come pick them up. Luckily, there was another window in the bad weather this morning, and Zach and Bishwo were able to join me for our work, and that same helicopter took our samples home to be processed while we added the treatments.

We needed to add water solutions containing carbon, nitrogen, phosphorus, carbon+nitrogen, carbon+phosphorus, or just water (as a control) to eight sets of replicate plots at Fryxell. We carry the solutions to the field in 35 ten-liter carboys, and then transfer 5.6 L at a time to pour jugs with sprinkle caps to be applied to the plots. It takes a lot of organization and communication to apply the treatments to the plots without messing up. We can't add the wrong solution to the wrong pour jug, or pour the wrong solution to the wrong plot. If we mess up and add a nutrient to a plot that's not supposed to receive nutrients, we ruin years worth of data and the future of a long-term experiment! So, it was a challenge to do the work with so few people in a short amount of time, but without rushing and messing up. We worked out a system where I filled the pour jugs for Zach and Bishwo, who were each assigned to a particular nutrient treatment. We check and double-check that I'm filling their jug with the correct solution. Then I direct them to the correct plot to apply their treatment using a map. We have to check and double-check that they're at the correct plot before applying the treatment to make absolutely sure that the wrong solution doesn't get used. They use a fiberglass cone to contain the water to the necessary area while they pour in a spiral pattern. Otherwise, the wind would blow it away from the plot! Once they've applied the nutrient solution, they come back to be refilled. We're constantly talking to each other and looking where we're going. Here's a short view of how it worked:

video

Unfortunately, the weather went bad again, and now Zach and Bishwo are stuck at F6 with me! It's snowing outside as I type. But, at least the work is done and the samples are at home. The rest of the Dartmouth crew is busy in the lab processing the samples, because we're planning to do the second site for the Stoichiometry Experiment on Friday!