My Research
Extracellular Enzyme Activity (EEA) in Arctic Soil
|
The Arctic region stores nearly half of the globe’s soil carbon (C) supply. As global temperatures increase, the frozen soils thaw, making stored C more accessible to soil microbes. Plants absorb atmospheric carbon dioxide from the atmosphere during photosynthesis. During fall senescence deciduous plants shed their leaves, which fall to the ground and become litter. During decomposition, soil microbes release enzymes that reduce litter complexity by cleaving chemical bonds. These extracellular enzymes can also make plant nutrients more available to soil microbes.
The C balance of northern ecosystems is controlled by the difference between ecosystem carbon gains, through greater primary productivity and microbial growth, and losses through increased soil organic matter decomposition In the Arctic, this balance has been disrupted due to rising temperatures that may release more carbon than can be fixed through photosynthesis. Understanding the relationship between increased C accessibility and microbial activity in Arctic soils will provide us with insight on how rising global temperatures will affect the rate of greenhouse gas emissions to the atmosphere in the upcoming decades. The two specific Arctic vegetation types we looked at are Betula nana and Eriophorum vagniatum . Betula has a carbon to nitrogen ratio (C:N) of 20 to 1, while Eriophorum has a C:N of 50:1. Compared with Eriophorum, Betula is nitrogen rich, therefore carbon-acquiring enzymes may be more active in Betula dominated soils, while nitrogen-acquiring enzymes may be more active in Eriophorum dominated soils. Understanding enzyme activities under these two vegetation types will give us a better idea of soil nutrient availability and the balance between carbon gains and losses in these systems. |