Organic matter in karstic aquifers: a potential tracer in the carbon cycle. A small-scale laboratory model approach
Abstract
In karstic aquifers, organic carbon is a potential tracer of the fast
flows coming from the soil. To study natural tracing using organic carbon,
during karstic flows, we focused on the degradation of organic matter by
bacterial activity during the infiltration of water. To demonstrate the impact of
TOC (total organic carbon) mineralization on the TDIC (total dissolved
inorganic carbon), we created a small-scale model of a karstic aquifer to study
the kinetics of degradation for dissolved and particulate organic carbon in two
different closed systems, one without carbonate and the other with limestone.
During the three-month experiment we found that the proportion of C02
produced by mineralization is significant. Therefore the production of C02
resulting from the mineralization of organic matter must be considered in the
carbon balance of karstic aquifers.