Comparison of Aquatic Invertebrates in Pool and Riffle Habitats of Blackburn Fork Comparison of Aquatic Invertebrates in Pool and Riffle Habitats of Blackburn Fork Michael Railling Department of Biology Undergraduate Student Tennessee Technological University Cookeville, TN USA

Introduction/Background The Blackburn Fork is a productive 4th order stream in Jackson and Putnam counties (Baker 1994). On 9/14/03 a sampling effort was conducted along a 100 meter stretch of Blackburn Fork to compare macroinvertebrate community structures between pool and riffle habitats. This is the background used for the research. ► Stream macroinvertebrate assemblage varies at both regional and local scales (Heino et al. 2003). ► Lower water quality is directly associated to diversity (Heino et al. 2003). ► Abundance of the macroinvertebrates can be affected by many factors but habitat is the prime factor (Waters and Giovanni 2002). ► Some may prefer the larger cobble and faster currents of a riffle and other may prefer the slower and bedrock substrate found in a pool (Cushing and Allan 2001). ► Pools generally have higher dissolved oxygen levels and a more neutral pH. Water Qualities In pH and dissolved oxygen can have a significant effect on the biota (Boto and Bunt 1981).

Objective/Hypothesis Statement ► Hypothesis: Are aquatic macroinvertebrate assemblages the same in pool and riffle habitats in Blackburn Fork? ► Objective: To show that different taxa are found pool and riffle habitats using taxa richness and percent EPT’s and percent Chironomidae.

Methods and Materials ► 6 Hester-Dendy samplers were used qualitatively, 3 in pools and 3 in riffles. Hester-Dendy ► Two samplers from each habitat were scrubbed and seperated. ► Invertebrates were identified to genus. Invertebrates were identified to genus. Invertebrates were identified to genus. ► Results were scored using data forms to show the taxa richness, percent EPT’s, and percent Chironomidae (Tennessee Department of Environment and Conservation 2002).

Results and Discussion ► In all 17 taxa were found in riffles and 11 were found in pools (Table 1). Two of the taxa, Antocha and Nigronia serricornis were found in higher numbers in the riffle habitats. The presence of these genra is directly associated with higher dissolved oxygen concentrations (Weigel et al. 2003). Table 1Table 1 ► Seventeen EPT’s were found in the riffle habitats for a total of 3.78% (Table 2, Figure 2) Table 2, Figure 2Table 2, Figure 2 ► The pool habitat had 26 EPT’s for a total of 3.97% (Table 2, Figure 1). Table 2, Figure 1Table 2, Figure 1 ► A total of 416 Chironomids were found in riffles; making up 92.44% of the total composition (Table 2, Figure 2). Table 2, Figure 2Table 2, Figure 2 ► Table 2 and Figure 1 show that 627 Chironomids were found in the pool sites making up percent of the total composition. ► I agree with Marshall (2001) that taxa richness directly corresponds with water quality, however I disagree that percent EPT corresponds with the water quality in my research. ► My results back Marshall (2001) that Chironomidae are more abundant in poor water qualities.

Summary ► 3 samples were taken from pools and 3 from riffles riffles within a 100 meter stretch ► The lower water quality pools had higher percentage of Chironomidae, higher percentage of EPT’s, but had less richness. ► The higher water quality riffles had higher richness, less Chironomidae, but had lower percentage of EPT’s.