Big Spring Number Eight (BSNE) isokinetic wind aspirated samplers were deployed at seven collection sites throughout the McMurdo Dry Valleys. These samplers passively collect 95% of airborne material that enters the collection box opening, regardless of wind velocity or direction. Though the aeolian material collection trays were initially set to standardized heights above the surface (5, 10, 20, 50, and 100 cm), strong winds generated variation in heights among the individual units. Therefore, relative elevation terms (bottom lower, bottom middle, bottom upper, middle, and top) are used in this work rather than absolute heights.

Aeolian material from Alatna, Victoria, Taylor (Explorer's Cove, F6, East Lake Bonney, and Taylor Glacier), and Miers Valleys was collected seasonally in 2013 and 2014 and year-round for 2015. Fifty-three samples were obtained, with 38 samples containing more than 5 g. Samples were collected twice: once in November and again in January. November collections are termed “winter” (from 15 January to 31 October), while January collections are termed “summer” (from 1 November to 14 January).

With samples with greater than 5 g of mass, 0.5 g of sample was leached with 2.5 ml of 18 Ω deionized (DI) water chilled to 3 °C. Samples with ~5 g of mass were leached using the entire mass of the sample. Sequential leaches of aeolian material were performed at a 1:5 sediment:DI water ratio. For the first leach, samples were agitated for 1 min by hand then set to rest at 3 °C for 30 min. After 30 min, the water from the first leach was extracted and filtered using a 0.45-μm Whatman® polypropylene syringe filter and stored in a clean Falcon™ tube at 3 °C in preparation for chemical analysis. The first two to three drops of leachate were discarded to minimize potential contamination from the filtration process. The second leach followed a similar procedure, but the extraction lasted for 24 hr. These two time steps were chosen to ideally simulate short pulses of water hydrating aeolian sediment in the McMurdo Dry Valleys to dissolve rapidly soluble solids (30 min) and long-term wetting (24 hr). 

Soluble reactive phosphorous (PO₄^3-) and nitrate plus nitrite (NO₃^- + NO₂^-) analyzed on a Skalar San++ Automated Wet Chemistry Analyzer with an SA 1050 Random Access Auto-sampler. Cations were analyzed using a Dionex DX-120 ion chromatograph (IC) with an AS40 automated sampler and anions were analyzed using a Dionex ICS-2100 ion chromatograph and an AS-DV automated sampler.