This study was conducted on the South Fork of the Kings Creek research watershed (outlet location: 39.092281, -96.58719) within Konza Prairie Biological Station (KBPS) near Manhattan (KS, USA). At the USGS gage located on the mainstem (06879560; est. 1979), Kings Creek is a 5th order intermittent stream draining 1059-ha of tallgrass prairie that is actively managed using controlled buns at varying frequencies (1-20 year return intervals) and grazing by bison or cattle. Kings Creek ranges in elevation from 338 to 430 m above sea level and drains into the Kansas River. The region is within a midwestern continental climate, with temperatures ranging from 4 to 22°C and mean annual precipitation averaging about 780 mm/yr.

This site lies within the Flint Hills ecoregion of eastern KS and northeastern OK, has a mean annual temperature of 11.7ºC (1983-2020), and 811 mm annual precipitation (1983-2020) with high interannual variability and an estimated 75% of annual precipitation occurring during late spring and early summer (Hayden 1998, Sadayappan et al. 2023). The AIMS study catchment, the South Fork of Kings Creek, is grazed by bison year-round, and includes sub-catchments with variable prescribed burn history, but the entire study area was burned in early April 2021. The riparian vegetation is deciduous gallery forest and the highest portion of the landscape is tallgrass prairie (Dodds et al. 2004) dominated by warm-season grasses, though woody encroachment has occurred in most subwatersheds (Sadayappan et al. 2023)*. The underlying bedrock of the Flint Hills ecotone is characterized as limestone, mudstone, and shale with predominately silty clay loam soils that rest atop (Hayden 1998, Vero et al. 2018).

Sample collection followed 3 approaches: (1) sampling at the outlet site ~every 3 weeks (SFM01) from 2021-2025, (2) sampling at 7 spatially distributed long term monitoring sites (LTMs) seasonally from 2023-2024, and (3) synoptic survey design to support the sampling goals of the Aquatic Intermittency effects on Microbiomes in Streams (AIMS) Project. During June 2021, a field team co-collected datasets characterizing stream microbiota, biogeochemistry, and hydrology across 50 locations within a sub-drainage of the South Fork of Kings’ Creek. The 50 sites were selected to balance multiple competing priorities: (i) strategically targeting existing monitoring infrastructure with long-term data (n=14); (ii) including sites near several known springs and tributary junctions (n=9); and (iii) including a range of drainage area and topographic wetness index (TWI) values (n=27), both of which have been correlated with flow permanence elsewhere. For a detailed description of the site selection process, please see (Swenson et al., 2024). Subsequent sampling events occurred in July and August to capture watershed contraction.
Samples were filtered with a 0.45um PES filter and frozen until analysis. Aqueous concentrations of anions were determined using an IC-3000 IC system (Dionex, Sunnyvale, CA) equipped with Dionex AERS 500 suppressor (2 mm, Thermo Scientific) and Dionex AS auto-sampler (Thermo Scientific). A Dionex IonPac AS15 column (2 mm × 50 mm, Thermo Scientific) with a guard column Dionex IonPac AG15 (2 mm × 50 mm, Thermo Scientific) was used to separate anions using a mobile phase of 38 mM KOH and a flow rate of 0.3 mL/min. The column temperature is 30 °C. Chromeleon software 7.1 is used for system control. Final data tab shows average of triplicates collected in the field and st dev of triplicates. Any NO3 values below 0.01 mg/L are below the lowest standard used in lab analysis and should be interpreted with caution.

The final data tab includes QA/QC’d averaged data for fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate in ppm with standard deviations. If the sample is below detection (BD), it is denoted as that and highlighted pink. Average NAs indicate analytes were not run or that samples were missing. NA’s in the standard deviations columns could indicate that those samples were not run or that only replicate was able to be analyzed.