These samples were collected in support of the core sampling goals of the Aquatic Intermittency effects on Microbiomes in Streams (AIMS) Project. This study was conducted in the Talladega research watershed (outlet location: 33.76219799, -85.59550775) in the Talladega National Forest (Cleburne County, AL, USA). The watershed drains a non-perennial unnamed tributary of Pendergrass Creek, and contains 0.92 km^2 of mixed coniferous and deciduous forest in the Piedmont Upland physiographic section. Located near Anniston, AL, the watershed spans an elevation range from 345 to 456 m above sea level and is a tributary to the Coosa River (within the larger Mobile-Tombigbee basin). The region has a humid subtropical climate, with mean daily January and July air temperatures of 5.3°C and 25.3°C respectively, and mean annual precipitation of 1,400 mm/yr. Between 29 March 2022 and 4 October 2024, grab samples for cation determination were collected at the watershed outlet (TLM01) every 3 weeks during routine sensor maintenance (AIMS Approach 1), seasonally at seven distributed, long term monitoring sites (AIMS Approach 2), and during a large synoptic sampling efforts concentrated across the watershed (AIMS Approach 3). Samples were filtered in the field with a 0.45um PES filter and acidified to 2% nitric acid for preservation until analysis. Immediately prior to analysis, samples were filtered with a 0.2um PES filter. Aqueous concentrations of cations were determined using coupled plasma-atomic emission spectrometry (ICP-AES) (Horiba Ultima 2, Horiba Jobin Yvon) fitted with an AS 500 autosampler. The instrument has a glass concentric nebulizer equipped with a cyclonic chamber. The generator power is 1000 W. The plasma and auxiliary gas flow rate are 12 L/min and 0 L/min. The sheath gas flow rate and nebulizer are 0.2 and 0.8 L/min. Argon pressure is 80 psi. Multi-elemental standards are prepared in 2% nitric acid as well.

Intermediate tab has data from all triplicates; final data shows only triplicate average, st dev, and RSD (relative st dev). RSD (relative standard deviation is included in intermediate tab; red color indicates values above 10%). We recommend that users use what is presented in the final data tab, as not every replicate has been accounted for and the data has been cleaned.

Low standard for each analyte (below): our lab uses this as the conservative detection limit/LOD. Na - 0.5 ppm / Ca - 0.5 ppm / B - 0.02 ppm / Mg - 0.5 ppm / Si - 0.5 ppm / K - 0.2 ppm / Sr - 0.05 ppm. Note: Boron (B) is almost always below our lowest standard. Most of this data is not useable/below our minimum standard.