(2008) Ozarks - Organic Nutrient Pulses in Karst Spring


Springs are unique freshwater ecosystems that represent the dynamic interface between subterranean and epigean systems. Springs are numerous in Southwest Missouri because the area is physiographically dominated by karst features. Springs are being lost at an accelerating rate, threatened through their use as sources of drinking water/commercial bottled water operations, stock watering, and irrigation. Karst systems are sensitive to organic pollutants as surface contaminants can readily infiltrate subterranean storage areas, providing an opportunity for later movement into springs. Sources of organic enrichment in lotic systems are numerous and range from sewage treatment plants, leaky septic tanks, feedlots, and livestock barns to natural inputs of leaf litter.

Clear Creek Spring, in the Springfield Plateau region of Missouri just north of the City of Springfield, has experienced serious groundwater pollution problems since May 2006 from several organic waste dumps (including manure) in the basin. Dumping occurred in and near sinkholes whose flow-paths have been shown to lead to Clear Creek, resulting in severe chemical and physical changes to the system.

Chemical analyses showed that four of the major pollutants in this spring also occur in decomposition products of cattle manure and other organic wastes. Organic matter from human or agricultural wastes enters aquatic food webs through subsurface-surface water exchange and is consumed by invertebrates via biofilm, benthic algae, or various heterotrophs.

This project sought to provide insight regarding the effects of this manmade increase in imported organic matter (organic pollution) on specific variables. This study provided an important baseline biodiversity survey for Ozark karst spring systems to guide in the maintenance and development of instream flow policies and management criteria for the allocation of groundwater for agricultural and human consumptive needs.

Moreover, by tracing the impact of organic pollutants, valuable information gained regarding nutrient dynamics at the surface water-groundwater interface could be applied to pollutant and water quality management options for karst systems.