New Mexico Geological Society Annual Spring Meeting — Abstracts

Bitter Lake National Wildlife Refuge in southeastern New Mexico (NM) was established in 1937 to preserve the habitat of migratory waterfowl and to protect wetlands surrounding the Pecos River near Roswell, NM. Such wetlands have developed around a series of playa lakes, water-filled sinkholes (sinks), and surface springs. These spring systems are threatened by regional climatic conditions in addition to direct anthropogenic influences such as groundwater development. The goal of this project is to characterize the water chemistry of sinks at the Refuge and identify hydrologic pathways that maintain these sinks. In addition, these efforts will be used to supplement ongoing biological research activities at the New Mexico State University (ichthyology) and University of New Mexico (entomology). In particular, this research will identify the presence of specific chemical components within the water that can be used as tracers to investigate groundwater flow, pollution implications, and sources of accumulated toxins in biota tissues.

Water chemistry for a subset of approximately 20 sinks throughout the northern portion of the Refuge is presented, and results are compared with existing data sets. Preliminary measurements indicate pH ranges of 7.14- 8.97 and conductivity ranges of 8.58-106.6 mS/cm; such parameters can vary widely between sinks only meters apart. An additional component of this project involves developing procedures to monitor the subsurface chemistry at high temporal resolution for extended time periods to assess the system sensitivity to atmospheric and seasonal changes. In order to investigate microbial activity, sediment and water will be cultured by inoculating microbial-specific media, as well as filtering water to obtain DNA; the aim is to identify and isolate anaerobic microbial activity throughout the water column. Microbial communities are essential primary producers supporting the complex and unique ecosystems that have developed within individual sinks.