Summer deposition of sulfate and reactive nitrogen to two alpine valleys in the Canadian Rocky Mountains

Background atmospheric sulfate deposition at a remote alpine site in the Southern Canadian Rocky Mountains

“…Anion and cation concentrations were determined simultaneously using a Dionex ICS‐3000 system in the Department of Geography, Queen's University [ Wasiuta et al, ]. Samples were processed for δ 34 S‐SO 4 2− and δ 18 O‐SO 4 2− analysis at the University of Calgary Isotope Science Laboratory (ISL) and prepared for analysis as barium sulfate (BaSO 4 ) precipitated from concentrated samples [see Wasiuta et al, ]. δ 34 S‐SO 4 2− values are expressed in δ units (‰, parts per mil) relative to Vienna‐Canyon Diablo Triolite.…”

“…Dissolved nitrate δ 18 O‐NO 3 − was quantified using the denitrifier method at ISL and Brown University and discussed in detail in Wasiuta et al []. The coexistence of NO 2 − and NO 3 − in samples analyzed by the denitrifier method and corrected to NO 3 − reference materials can produce apparent δ 18 O‐NO 3 − values that are ~ 25–30‰ too low [ Casciotti et al, ].…”

Atmospheric deposition of sulfur and inorganic nitrogen in the Southern Canadian Rocky Mountains from seasonal snowpacks and bulk summer precipitation

“…Here we ask the question: is atmospheric S and N deposition spatially uniform implying these compounds in snow are derived from distant emission sources in well mixed air; alternatively do local and regional sources of S and N dominate atmospheric deposition in high alpine regions of the southern Canadian Rocky Mountains? For consistency with related research results (Wasiuta et al, 2015) emissions originating within a half day of air mass transport (50-400 km) are considered local, while emissions within two days of transport (290-680 km) are regional, and sources further away are distant.…”

“…The snowpack N deposition at HG2770 was the mean of the nine sites sampled in the 2009 regional survey. Wasiuta et al (2015) showed that summer N deposition was more spatially variable with substantially higher N deposition in the adjacent valley. This suggests the existence of alpine sites in Western Canada that receive substantially higher annual N deposition than the Haig Valley.…”

Atmospheric dry and wet nitrogen deposition in agro-pastoral catchments of the China and Mongolia Altay

“…Although some N deposition studies have been conducted in agricultural and 68 pastoral areas (Luo et al 2003;Li et al 2012;Du et al 2014;Basto et al 2015;Huang 69 et al 2015;Liu et al 2015;Wasiuta et al 2015), little research has been conducted to 70 quantify atmospheric N deposition in the agro-pastoral zone. In China over 12 71 provinces comprising 160 towns and around 117 million people depend on this 72…”