10 June, 2001
The sun is trying, and succeeding at times, to shine through the clouds and then we had 5pm snow flurries! Weather changes quickly here. Things are warming up and the effects are noticeable just overnight. The amount of visible tundra has increased and the amount of clothes Iím wearing is decreasing. That inverse relationship will probably be the trend for the next few weeks. One cannot survive without high rubber boots here. One arcticle of clothing which stays all winter and all summer are the knee-high rubber boots. They keep the snow out, the mud out and the water out.
I programmed the LI COR this afternoon. This instrument (pictured below) is a portable photosynthesis measuring system. When in use we will use it to give us CO2 flux measurements from the vegetation at the site. Everything we are doing here revolves around quantifying amounts of CO2 being stored in the tundra and being released from the tundra. Why so much time and energy spent on this gas?
As you probably already know there is much concern over the prospect of global climate change and the effects such a change would have on the earth as a system. The earth is naturally warmed by the sun's energy; light photons pass through the atmosphere unimpeded, strike something solid and the energy is transformed from light energy to heat energy, a longer wavelength of energy. This heat, being less dense (lighter) then the air around it rises and if it doesn't get absorbed by any heat trapping gases or reflected back to the surface by clouds, it will rise and dissipate into the upper atmosphere. There are naturally occurring gases in our atmosphere that do act to absorb some of the heat energy and this is beneficial for you, the planet and me. This trapped heat keeps the planet warm and provides us with a very nice and comfortable place to live. The gases that make this possible are the Greenhouse Gases(GHG), which include, CO2 (carbon dioxide), CH4 (methane), O3 (ozone), N2O (nitrous oxide) and H2O vapor. The 6th GHG is (H)CFC (chlorofluorocarbons), which is a manmade GHG.
This is why scientists like Glen Kiroshita, who I am working with, want to find out what the arctic is doing with its stored carbon. Historically, up until about 10 years ago, it was thought that the frozen arctic was a sink (absorber) of carbon. The plants would take in the CO2 during photosynthesis and then when winter came the vegetation would freeze, locking the CO2 away in the frozen ground. In the last several years it has been shown that this is only a partial picture of what happens. Since the tundra makes up 5% of the land area of earth what happens here represents a significant amount of CO2 on the global scale of things.
It was thought that if warming is occurring arctic tundra plants would have a longer growing season (temperature wise) thus more plants would grow and they, it turn, would absorb more carbon from the atmosphere. What Walt Oechel the PI on this project and Glen who works with Walt, have seen is that does occur initially, for the first 2 or 3 years but temperature is only one of a number of variables which vegetation depend on to grow. Some of the others ingredients necessary for growth are H2O, light and sufficient amounts of specific nutrients, the main one being nitrogen. Tundra soil does not have much available nitrogen so that becomes a significant limiting factor to plant growth. After the first 2 or 3 years of increased vegetation production it was seen that healthy plant growth was slowed. The plant productivity did reach a balance and returned to what occurred the previous years.
Arctic soils do not break down nutrients as fast as other, more temperate areas do mainly to the extreme climate. The cold tends to preserve rather then break down matter here and so nitrogen, though in the soil, is basically unavailable and limits plant productivity.
Why study CO2?
More CO2 = a warmer earth. If arctic plants are not using more of the available CO2 we end up in a positive feedback loop and things potentially keep getting warmer.
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