Debra S. Baker and Donald G. Huggins Nutrient Trends in Reference Streams of the Central Plains Debra S. Baker and Donald G. Huggins Central Plains Center for BioAssessment Kansas Biological Survey, University of Kansas 30th Annual Great Plains Limnology Conference, Lincoln, NE, 10 – 11 October 2003

Nutrients in Streams Clean Water Action Plan 1998 - USEPA initiative to establish regionally-based nutrient criteria for waterbodies via Regional Technical Assistance Groups (RTAGs). Develop a dataset of nutrient levels found in “reference” or least impacted streams of USEPA Region 7. Should criteria be single values for the entire EPA Region, or should criteria be based on a subset of stream characteristics, such as ecoregion?

Stream Sites

Parameters in situ: DO, turbidity, pH, conductivity Lab analysis: TN, NH4-N, NO3-N, TP, PO4-P, chlorophyll a, phaeophytin a

Hypothesis Streams will show affiliations based on some suite of water quality characteristics (e.g. nutrient concentrations). Principal Components Analysis (PCA) was used to determine probable relationships among the parameters. Resulting factor scores were used as input for clustering analyses to identify stream groupings and compare resulting spatial differences to ecoregions. Analyses

Resulting Dataset May 1999 – June 2002 94 streams, 522 records, taken at base flow TN: 5 – 20410 g/l; Median: 1180 g/l TP: 2.5 – 1320 g/l; Median: 86 g/l Chlorophyll a: 0.5 – 216 g/l; Median: 4 g/l

PCA Analysis Factor 1 TP, PO4-P Factor 2 TN, NO3-N Factor 3 chlorophyll a, phaeophytin a Factor 4 pH, DO Factor 5 conductivity Factor 6 NH4-N

K-means Cluster Analysis Calculated medians of the 6 PCA factor scores for each of the 94 sites. K-means cluster analysis on all PCA factors – resulted in 6 clusters. K-means cluster analysis on just the nutrient factors – resulted in 6 clusters.

Clustering on All Factors

Clustering on Nutrient Factors

N & P Factors

N & P Factors

N & P Factors

N & P Factors

N & P Factors

N & P Factors

N & P Factors

The 94 reference streams vs The 94 reference streams vs. a database of nonreference streams (# records ~ 24000; # streams ~ 1500)

Conclusions Nutrient levels varied by ecoregion. Streams that we clustered by nutrient factors and independently of ecoregion showed ecoregional affiliations.

Future Study Seasonal influences Chlorophyll a USEPA Region7 Nutrient RTAG Macroinvertebrates Watershed and land use