Environmental Sciences and Biogeography
Cave and Karst Systems
| An understanding of the interplay of hydrology and biogeochemical processes that
control transport and processing of nutrients in karst watersheds is critical to the
design of sustainable land-use practices over karst terrains. Our understanding of
the processes operating in karst systems, however, lags considerably behind that of
other aquatic ecosystems (such as marine, riverine, wetlands, and granular aquifers).
The availability of dissolved organic matter, a strong control in biogeochemical cycling
of nutrients within the karst soil system, is easily altered by agricultural, wastewater
treatment outfalls, septic systems, and other activities in the karst watersheds.
Whereas karst ground-water movement has recently received focused study, controls
on the carbon availability and movement, particularly the DIC-DOC-CO2 (g) dynamics have received little attention. Carbon is the basic substrate which
must be available for processing nutrients--and specifically nitrate. Basic geochemical
monitoring is being conducted which includes continuous pCO2 measurement and isotopic characterization of DIC and DOC behavior moving through
the karst-soil system. These data are facilitating source identification and delineation
of the complex interaction between water quality and nutrient cycling in karst. This
project will establish controls on the effect of carbon cycling and local hydrology
on the effective processing of nutrients in mantled-karst watersheds of the Ozarks.
Currently we are working in a cave system in Madison County to help understand the interplay of climate, hydrology, and nutrient processing. Sampling infrastructure design aims at collection of soil gas, soil water, ground water at various points moving along flow paths including caves, and cave CO2. The data set being accrued will help draw direct correlation between the surface conditions and cave responses and enable elucidation of controls on nutrient processing. Data also will allow for characterization of climate effects with improved understanding of CO2-speleothem dynamics and the development of the archived climate records of the cave system.