Biology
The study of biological communities is a useful tool in understanding water quality. Fish, invertebrate, and algae communities live and thrive under different water-quality conditions. Analyses of biological communities are important because they incorporate and integrate effects from water chemistry, habitat, and hydrology. Looking at chemistry, habitat, and hydrology alone may cause scientists to misinterpret conditions in a stream. Because biota live for varying periods of time, studies of biological communities can be used to analyze short-term effects (invertebrates and algae) and long-term effects (fish). For these and other reasons, the study of biological communities is a critical part of the NAWQA study design.
During Cycle I (1991-2000) of NAWQA, ecological data were collected at all surface-water sites. Eleven sites were in the White River (WHIT) Study Unit and eight were in the Great and Little Miami (MIAM) Study Unit. These sites represent the dominant hydrologic, geologic, and land-use settings in the Study Unit. Two types of sites were sampled: basic and intensive. Intensive sites were sampled more frequently than the basic sites. Multiple reaches were sampled to measure the amount of variability associated with each reach. For 1 year of the highest intensive sampling period, a subset of intensive sites were sampled for multiple reaches. For the WHMI (map inset), four of the six trend sites were sampled for multiple reaches.The sites in Indiana were Sugar Creek at New Palestine, Little Buck Creek near Indianapolis, Big Walnut at Roachdale, and the White River at Hazleton. In Ohio, Holes Creek at Kettering and Mad River near Eagle City were sampled in 2000 for multiple reaches and will be sampled again during NAWQA Cycle III.
Variables collected as part of the NAWQA Ecological Component include:
- Fish, invertebrate, and algae communities.
- Periphyton Algal Biomass (Chlorophyll a and ash-free-dry-mass).
Protocols for all of the ecological sampling can be found at NAWQA Protocols.
Mercury samples were collected as part of a NAWQA national occurrence and distribution study. Samples were collected from fish tissue, sediments, and water in 2002 at eight sites in the White River Basin. Eight sites were sampled for the same parameters in 2000 in the Great and Little Miami Basin. Sites selected in the WHIT Basin included four agricultural sites, one urban indicator (small stream) site, one urban integrator (large stream) site, and two reference sites.
