Appendixes and Evaluation of Quality Assurance Data 


Evaluation of Quality Assurance Data


Quality assurance data tables are presented in the appendices and the results are summarized below. Two equipment blank samples were collected for nutrients, resulting in no detections for the first sample and two low-level detections in the second sample: 0.1 mg/L total Kjeldahl nitrogen (TKN) and 0.014 mg/L soluble reactive phosphorus (appendix D). The TKN detection was at the laboratory reporting limit and represents a low-level detection for this constituent. The ambient stream concentrations of TKN were generally low, about 2–3 times higher than the concentration reported in the blank. The phosphorus detection in the one blank sample was higher than any concentration measured in the stream; the detection in the blank, therefore, appears to be an isolated case. There were two replicate nutrient samples (appendix D) which, for the most part, were within ±10 percent. Exceptions occurred for dissolved ammonia, which had relatively high percent relative differences of 69 and 90 percent, but were within reason given the low concentrations as all replicate values were less than the laboratory reporting level of 0.02 mg/L. The percent relative differences for the two TKN replicate samples ranged from 6 to 20 percent, but were reasonably close considering that all values were relatively low and close to the laboratory reporting level of 0.1 mg/L. 


One set of replicate samples analyzed from separate collections of stream cobbles were analyzed for algal biomass, species identification and enumeration. Although the replicate biomass samples were reasonably close (within 7 mg chlorophyll-a/m²), these samples differed considerably with respect to the species composition (appendix E). About one-half of the species were identified in only one of the two replicates. Based on the relative density, the top three dominant taxa were the same for both samples, but based on biovolume, one sample (replicate #2) was dominated by the large stalked diatom Gomphoneis herculeana whereas this taxa was not identified in the first replicate sample (appendix E). This difference highlights the often patchy growth of periphyton (Cazaubon and others, 1995), particularly for macroalgae, which in the Pacific Northwest includes G. herculeana and other large stalked diatoms (Bahls, 2007), filamentous greens (Cladophora and others), and filamentous blue-green algae including Oscillatoria, Phormidium, and others (Anderson and Carpenter, 1998; Carpenter, 2003). These types of algae are much larger than typical diatoms and other microalgae and may be missed under high magnification, especially in 100 algal unit counts used for this study. Abundance values from the two replicate samples were averaged for all further analyses.


Appendixes A-G are included in a Microsoft© Excel workbook, which can be downloaded from http://pubs.usgs.gov/sir/2012/5017/.


Appendix A. Particle size distributions collected using Wolman (1954) Pebble Counts on nine freshly deposited bars along the river corridor of the Molalla River, Oregon, September–October 2010.


Appendix B. Periphyton species abundance data (cell density) in the Molalla River, Oregon, August–September 2010.


Appendix C. Periphyton species abundance data (algal biovolume) in the Molalla River, Oregon, August–September 2010.


Appendix D. Quality assurance data for total and dissolved nutrients in the Molalla River, Oregon, August–September 2010.


Appendix E. Quality assurance data for replicate periphyton species composition samples from the Molalla River, Oregon, 2010.


Appendix F. Nutrient and field parameter data for the Molalla River, Oregon, June 26, 2000.


Appendix G. Field parameter data for the Molalla River, Oregon, 2000.

First posted February 29, 2012