Yes, Biosphere 2, that 3.15 arce "bubble," was my home for the summer of 1998. And actually I'm still here! And for now this is it- a description of my project and a few pictures. When I get more time I'll actually write up some more interesting things, put a few links in, and get a whole lot more pictures up. Until then!
Biosphere 2, a 7,200,00 cubic foot sealed glass and spaceframe structure, with all living elements taken directly from Earth (Biosphere 1). Inside are seven ecosystems, five wilderness and two human-oriented. They are: a rainforest, a desert, a marsh, a savannah, a 900,000 gallon ocean, an intensive argiculture biome (IAB), and a human habitat.
I worked over the summer as a NASA research intern at Biosphere 2. After a few weeks of wondering whether it was actually going to happen, my project was measuring and trying to define the light enviornment in the IAB. Since Columbia University took over managing Biosphere 2, about three years ago, they have progressively changed BIosphere 2's mission to include education as well as research. They have also begun implementing several different research projects inside the Biosphere which were not part of its original purpose.
One of these projects, the one I worked most closely with, is in the IAB. The Itensive Agriculture Biome was the place where the Biospherians grew all thier food and kept their livestock. It was basically a large continuos garden and farm, with the soil taken from nutrient rich farm land on Earth. When the human habitat was seperated from the rest of Bioshpere 2 so it could be opened to the general public, the IAB had to be seperated as well due to its location. Now it is effectively operating entirely on its own and sealed off from the rest of Biosphere 2. Another unique aspect is it was designed as three connected "bays." But last winter the West Bay was sectioned off by building a giant plastic wall and adding a small airlock between it and the rest of the IAB. Hopefully by the end of the year consturction will begin on the wall which will divide the Center and East Bays. In the end the idea is to have three identical bays for expierimenting in. And since the environment in Biosphere 2 is regulated, the enviornment in each one of the bays will be able to be controlled seperately. When all is ready, a specific aspect of the enviornment can be changed to be different within each bay, while keeping all other aspects the same in all three bays.
Currently the expieriment in progress in the IAB is using only the two sperate areas there are now (the West Bay and the Center/East Bay). It is a peliminary experiment to filter out any problems before beginning the real one. Which will be to grow a group of Cottonwood trees with different levels of Carbon Dioxide in the atmosphere. For this experiment this will be the one aspect of the enviornment of the three bays which will be different. One bay will have ambient levels (the same amount as is in Earth's atmosphere- about 360 parts per millon), one will have twice that amount, and the levels in the third bay is still being decided on. One idea is to have them be three times ambient levels, a level at which research on plants has not been done before. The point of the experiment is to gather data on how the trees will react to the higer levels of carbon dioxide. This experiment is being done in responce to the increasing levels of carbon dioxide in the Earth's atmosphere. Whether plants will be able to adapt to the increased levels of the future, if they will flourish or suffer or be uneffected, is a big question in enviornmental science today. The goal of the Cottonwood tree experiment is to provide some answers.
Here is a picture of part of the IAB before the cottonwood trees were planted...
Since my mentor for the summer, Dr. Kevin Griffen from Columbia University, is a botonist I worked a lot with the experiment on the cottonwood trees in the IAB. But my part in the peliminary experiment was to determine the light enviornment of IAB, if possible to do so. Then to determine if that light enviornment has a direct impact on how the trees grow. If there is one, then it will be known how the light enviornment will influence the trees during the real experiment and that can be factored out before it is determined how the elevated levels of carbon dioxide influence the trees. The light enviornment in the IAB is caused by the steel and glass structure (the space frame) which forms the IAB and acts as a kind of filter of the total sunlight which would reach the plants if the Biosphere was not there. For example, it has been shown that the glass of the space frame blocks all but a very small amount of UV light which reaches the Earth.
I worked on this project with Victor Engel, a graduate student from Columbia University. We placed seven light sensors in each bay of the IAB among the still young trees. Light sensors measure the amount of sunlight striking the sensor at a given moment and relay that information to a simple computer called a data logger. We programmed the data logger we used to record the light level every five seconds, and then after five minutes to average the values and save the average in a file for us to download later. We let the data logger and the light sensors run continuiously for three to four complete days in each bay. Since we only have seven light sensors, we unfortunately had to measure each bay seperately. But after fourteen days we had all the data we needed and I began anaylizing it. I have not finished yet, but the data seems to be working pretty well.
Another way used to try to determine the light enviornment was using fish-eye photography. Using a special half-sphere lense, fish-eye photography is able to take pictures of 180 degrees around the camera. A consultant, who specializes in using fish-eye photography, was brought in by my mentor at Biosphere 2 to take the pictures and analyze them. Because my project was the light enviornment of the IAB, I was allowed to assist with this. For the analysis to work the space frame of the IAB needed to be darker than the sky, so that the space frame will show up clearly in the photographs. Since the space fame is white, the only times it was darker than the sky was at dusk and dawn, which occur in Arizona at 8pm and 4:30 am. The reason the space frame is darker than the sky at these times is that as the sun rises the light starts high in the sky, lighting up the sky but leaving the ground (or space frame) dark. As the sun rises higher the light falls lower until it the ground is lit up with sunlight too. At sunset the reverse happens, as the sun lowers in the sky the light rises higher, leaving the sky light but the ground dark. We took around 150 photographs in the IAB. Due to the large size of the IAB, the complexity of the space frame, and the number of photographs taken, the analysis of the light enviornment using fish-eye photography will take a couple months.
In between working on my project I helped other people at Biosphere 2 with their's. I have taken height measurements of the cottonwood trees, as well as counting the number of branches and leaves each of the 283 trees have, every couple weeks. I also have taken temperature measurements of the air at ground level in the IAB and collected data on how well the trees photosynthesize until different light or carbon dioxide levels. This was accomplished with a little, but heavy, machine called a li-cor. Instead of changing the levels in the bay, this machine can change the light or CO2 levels for one leaf at a time by placing the leaf in a leaf chamber attached to the li-cor. After I collected all the data and numbers I graphed it. Some of the graphs are just regular ones, but a couple like the height of all the trees are three dimentional and a color scheme is added to them so that the data can be seen better.
Here's me working with one of the licor machines...
I did a lot of the things just mentioned with another intern named Angela Anderson, who was my partner for working in the Biosphere. As a result I ended up helping her a bit with her own project. Breiefly, her project was a scaled down version of the current IAB experiment, but with a little variation. She was researching how cottonwoods and corn plants grow under different levels of carbon dioxide as well. But instead of doing so within a closed system which can grow a whole forest, she used opentop chambers. Opentops only allow for four potted plants at a time. They work by continuosly injecting the amount of carbon dioxide desired in a given chamber through its bottom. It then mixes with the air in the opentop as it is blown through and out the open top of the opentop chamber. I helped Angela plant and later fix the leaking opentop chamers.
