From: Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment
We define present parameters as the principal components of all context |
data derived from (a) pore water analysis, which indicates that chemical |
gradients are caused by the consumption and production of ongoing |
biological processes (e.g., sulfate and methane), and from (b) directly |
measured parameters of microbial activities (e.g., bacterial protein |
production). The present parameters are therefore an expression of |
recent microbial processes. |
Past parameters are the principal components of conservative |
parameters, which once introduced into the sediments will not change |
significantly and are therefore an expression of the lake’s history (e.g., |
heavy metals). Here, we also categorize the total amount of elemental |
carbon, nitrogen, hydrogen, and sulfur as mainly conservative parameters. |
The past parameters are therefore an expression of historical changes. |