July 24, Greenhouse Experiment Options

[Leslie_Pierce]

July 24, 2005
Greenhouse Experiment

Sunday started out to be really nice and warm, a perfect day for getting outside. So, I called Rita Acker, an old student of mine who has been helping on a greenhouse project for the last four summers, to see if she and her cousin wanted to go to the greenhouses today. Her cousin, Krista Frantz, works during the week and the weekend is the best time to go and collect data. A few high school students and I have worked on this project with the help of BASC (Barrow Arctic Science Consortium) and the Arctic LTER (Long Term Ecological Research) Schoolyard Project. This summer two high school students are collecting data for the project, Krista and Rita’s sister, Donna Frantz. So far, all of the students that have participated in the past are cousins. So, we’re keeping it in their family!

Here's Rita and Krista.



Four plots (8ft x 4ft) were set up on the edge of the BEO, which is the Barrow Environmental Observatory (over 7,000 acres located northeast of Barrow). The BEO was set aside in 1992 for scientific research by the Ukpeagvik Iñupiat Corporation (the Barrow Village Corporation) and is used by many scientists on projects ranging from nesting birds, lemmings, and vegetation cover studies, to environmental monitoring of permafrost and carbon flux. UIC and BASC encourage student participation in research projects as well.

These four plots were picked because of the easy access to the road and still being located in the BEO. The project involves the study of warming and increased decomposition effects on the tundra. It was modeled after the tundra manipulation projects at Toolik (see TREC teacher Tom Crumrine’s project!) Two of the plots were left open or exposed (E) and two of them were covered with greenhouses (GH) to simulate global warming. One of the pairs of plots would be the controls, one for the exposed treatment (EC) and one for the greenhouse treatment (GHC). Each of these two plots contains sensors that are connected to an Onset Hobo Weather Station, including sensors for soil temperature, ground temperature, and relative humidity.

Here’s a picture of these two plots, the GHC on the left and the EC on the right, with the weather station between them.


The other pair of plots is fertilized to simulate an increase in decomposition of organic matter, one exposed plot (EF) and one greenhouse plot (GHF). Tundra soils are generally very poor due to the slow decomposition of organic matter, trapping nutrients in the layers of peat.

The plot on the left between Krista and Rita is the EF and the GHF plot is on the right.


The fertilizer formula that we use is from Hoagland’s Nutrient Solution which calls for 10 mg/m2 of nitrogen and 5g/m2 of phosphorus.

Krista measures out the chemicals ammonium nitrate (NH4NO3) and potassium phosphate (KH2PO4),


mixes them in buckets, and applies the solution to the EF and GHF.


Krista and Rita collected data on the depth of the active layer of the soil. They used a soil probe that is marked off in centimeters, pushed the probe into the soil until reaching the permafrost layer, and checking the depth. We also collected soil samples to be analyzed for nitrogen and phosphorus. At the end of the growing season (which is in about a week or so), leaf length of sedges and length and width of coltsfoot plants will be measured to be compared between the plots. Number of flowers or seed heads will also be noted. And, this year we will add biomass sampling! We will take 10-cm quadrat clippings of each plot as I did in the snow geese study.

Here’s Krista collecting soil samples,



and checking the depth of the active layer.


The weather station continuously collects other data besides just the soil and ground temperatures in the EC and GHC. It also collects ambient air temperature, light, wind, barometric pressure and rainfall. The girls will continue collecting data into September and we’ll take the greenhouses down before the first snowfall. They will have all fall to analyze their data. After four summers, they have a short-term data set to compare as well. The hope is that this project will continue for years to come!