Sentences with phrase «microbially driven source»

This time, the dominant carbon isotopic values in the new inputs were about -60 ‰, pointing to a microbially driven source rather than fossil fuel inputs.

As a result, methane emissions have distinct isotopic values: Methane emitted from any microbially driven source such as wetlands or agriculture have values of about -60 ‰ (signifying a relatively low ratio of carbon - 13 to carbon - 12); oil, gas, and coal emissions have an average carbon isotopic value of -37 ‰; and tree and crop burning averages about -22 ‰.