Supplement 1. Complete data set used in all analyses conducted in this manuscript, with corresponding metadata.

File List Nelson_etal_supplement.csv (md5: 76931e8b5d9cbfd8f730ba8b19972b1b) Description The file Nelson_etal_supplement.csv is a comma delimited text file containing all data used in the manuscript. Column definitions and units: Sample: A unique ID code for each sample collected Sample Type: Treatment (NDS agar sample) or Ambient (nearby rock scraping) Region: Sierra Nevada (SN) or Santa Ynez (SY) Stream: A two letter code for each stream (see Fig. 1 of the manuscript) Lat: decimal degrees Lon: decimal degrees Elev: meters Cover: % canopy cover Light: micromoles per square meter per second Vx: flow rate in meters per second Width: meters AmbNH4: ambient ammonium micromolar AmbNO3: ambient nitrate+nitrite micromolar AmbPO4: ambient orthophosphate micromolar S: Richness H: Shannon diversity index based on species density E: Simpson's evenness index based on species density D: Simpson's diversity index based on species density AbunA: Species density BiomA: Species biovolume in cubic microns per square centimeter N: nitrate concentration in agar at start molar (see notes below) logN: log10Nutrient concentration (See below) days: duration of NDS deployment in days R: respiration rate mg oxygen per square centimeter NDS surface per hour NPP: net primary production rate mg oxygen per square centimeter NDS surface per hour GPP: gross primary production rate mg oxygen per square centimeter NDS surface per hour P:R: ratio of GPP to R log10chla: log10(μg Chlorophyll a per square centimeter) SA:SR: ratio of richness on NDS agar to colonist richness from Ambient sample in stream Remaining columns are cell densities [ln(cells cm^-2)] of various functional and taxonomic groups as listed in Appendix A and Appendix C. Nutrient concentrations in NDS agar at start of incubation 1 = 1M NaNO3 : 0.0625M K2HPO4 in 2% agar (85g NaNO3 + 11.2g K2HPO4 + 2g agar in 1 L DI)<br> 2 = 0.01 M NaNO3 : 0.000625M K2HPO4 in 2 % agar (Diluted from 1)<br> 3 = 0.0001M NaNO3 : 0.00000625M K2HPO4 in 2% agar (Diluted from 2)<br> 4 = 0.000001M NaNO3 : 0.0000000625M K2HPO4 in 2% agar (Diluted from 3)<br> 5 = 0-control with just 2% agar (0g NaNO3 + 0 K2HPO4 + 2g agar in 1 L DI)