Nutrient Atmospheric Deposition on Utah Lake: A Comparison of Sampling and Analytical Methods

We describe modified sampling and analysis methods to quantify nutrient atmospheric deposition (AD) estimate Utah Lake loading. address criticisms of previous published collection methods, specifically table height, screened buckets, assumptions AD spatial patterns. generally follow National Atmospheric Deposition Program (NADP) recommendations but deviate measure lake AD, which includes from both local long-range sources. The NADP guidelines are designed eliminate contributions the extent possible, while loads should include contributions. collected side-by-side data with tables at 1 m (previous results) 2 (NADP guidelines) above ground two separate locations. found no statistically significant difference between different heights. Previous work assumed rates would decrease rapidly shore. interior show that do not significantly decline away This demonstrates be estimated by using available geostatistical even if all shoreline stations. evaluated screening buckets. Standard unscreened samples had up 3-fold higher concentrations than collections. It is clear best represent rates, we recommend use screens placed on sample buckets for majority 2020 exclude insects other larger objects such as leaves. updated load estimates Lake. computed total 350 153 tons phosphorous (TP) 460 505 dissolve inorganic nitrogen (DIN) 2017 2018, respectively. Using 262 133 TP 1052 482 DIN 2019 2020, results used samplers lower resulted in totals 2019. present these support help guide studies lakes reservoirs. can a amount included studies.