Resin Deposition Data
Ammonium, nitrate, inorganic nitrogen, and sulfate deposition was quantified using ion exchange resin tube collectors. These resin collectors contain pre-rinsed mixed-bed cation/anion exchange resin (Amberlite IRN 150). Collectors were deployed at each site, and within each site, we have 5 plots. Two collectors were placed in each plot: one in the open and one under the tree canopy. Blanks were included at each site (resin tubes constructed with a cap on one end but otherwise treated as the others) with all tube sets collected and exchanged mid-May and mid-October. During the October-May deployment, a 1-m supplementary tube was attached to the top of the precipitation collection funnel to capture snowfall. The retrieved resins were extracted with 1 M KI, filtered, and the extracts were analyzed for NH 4
+
-N (phenate method) on a Seal AA3 Auto Analyzer and for NO 3
-
-N & SO4 -
-S by ion chromatography (Dionex IC 5000). We subtracted volume weighted concentrations in blank resins tube extracts from concentrations in extracts from exposed resin tubes and corrected deposition values with laboratory-determined efficiency values.
Veg CNS Data
Vegetation samples were collected at 5 plots at each of our sampling sites at least three times per year (typically June, July, August) between May and October. Five replicates of each species were taken at each site on each sampling date. Protocols for new growth collections were species specific. Surface moss was collected for Sphagnum fuscum
and Sphagnum capillifolium
. The entire lichen thalli of Evernia mesomorpha
and the top 2.5 cm of Cladonia mitis
thali were collected. Ericaceous shrubs, Rhododendron groenlanicum
and Vaccinium vitis-idaea
collections included the topmost leaves from individual plants while all aboveground portions of Vaccinium oxycoccos
was collected. We collected the current year leaves from the deciduous forbes, Rubus chamaemorus
and Maianthemum trifolia
, and the apical shoots of the current year’s growth of the dominant tree Picea mariana
. Each sample was cleaned to remove debris, oven-dried (60 ⁰C), and ground with a Wiley micromill. Sample were analyzed for total C, N, and S concentrations with a LECO CNS analyzer.
Water Chem Data
To collect peatland porewater as a function of depth, we deployed three samplers at each of our sites. These samplers are made of stacked 20 cm long segments of 2.5 cm-diameter thinly slotted PVC pipe, with Tygon tubing extending to the surface from the bottom of each section. On each sampling date, a 60 mL syringe was used to empty the full volume of water from the topmost segment, water was allowed to slowly return to the segment, and a fresh 60 mL of porewater was collected from that segment. Each of the samples was field filtered through Whatman 41 filters into pre-washed sample bottles. Samples were taken at least 3 times (June, July, and August) during each of the summers of the study. The samples were frozen and shipped to Villanova University for analysis of NH 4
+
-N (phenate method, Seal AA3 AutoAnalyzer), NO 3
-
-N and SO 4
2-
-S (Dionex ion chromatograph), and total dissolved N (Shimadzu TOC-V analyzer with prefiltration through 0.45 µm filters).
Water Chem Data Detailed at Depth
To collect peatland porewater as a function of depth, we deployed three samplers at each of our sites. These samplers are made of stacked 20 cm long segments of 2.5 cm-diameter thinly slotted PVC pipe, with Tygon tubing extending to the surface from the bottom of each section. On each sampling date, a 60 mL syringe was used to empty the full volume of water from the topmost segment, water was allowed to slowly return to the segment, and a fresh 60 mL of porewater was collected from that segment. Each of the samples was field filtered through Whatman 41 filters into pre-washed sample bottles. Samples were taken at least 3 times (June, July, and August) during each of the summers of the study. The samples were frozen and shipped to Villanova University for analysis of NH 4
+
-N (phenate method, Seal AA3 AutoAnalyzer), NO 3
-
-N and SO 4
2-
-S (Dionex ion chromatograph), and total dissolved N (Shimadzu TOC-V analyzer with prefiltration through 0.45 µm filters). Conductivity and pH are also reported for each sample with all data presented to depth of up to a meter.
Plant and Lichen 15
N
Six peatlands were chosen for study. Five are in the Athabasca Oil Sands Region; the Utikuma site was chosen as a control (251 km from the oil sands industrial center), sufficiently distant from oil sands facilities to be unaffected by N and S emissions. Five of the sites (JPH4, McKay, McMurray, Anzac, Utikuma) are ombrotrophic bogs, with acidic porewaters, a nearly continuous cover of Sphagnum
mosses ( S. fuscum
and S. capillifolium
on hummocks, S. angustifolium
in hollows), and an abundance of ericaceous shrubs ( Rhododendron groenlandicum
, Vaccinium oxycoccos
, and Vaccinium vitis-idaea
). One of the sites (Mildred) is best described as a mixed mire with minerogenous water affecting lawns and carpets (circumneutral pore water pH) and ombrogenous hummocks dominated by S. fuscum
and, to a lesser extent S. capillifolium
. In general, these six peatlands represent a gradient of decreasing annual deposition of NO 3
-
-N, DIN, and SO 4
2-
-S with increasing distance from oil sands operations.
Deposition of NH 4
+
-N, NO 3
-
-N, DIN (NH 4
+
-N + NO 3
-
-N) and SO 4
2-
-S was determined using field-deployed ion exchange resin collectors (see metadata in same package: Resin Deposition Data).
At each site, we established 5 large representative “plots,” spatially distributed across the peatland. On each sampling date, from each plot at each site, with gloved hands, we collected 5 replicate samples, one from each plot, of Evernia mesomorpha
(whole thalli), Cladonia arbuscula
(top 2-2.5 cm of thalli; we did not distinguish between ssp. arbuscula
and ssp. mitis
), Sphagnum capillifolium
and Sphagnum fuscum
(about 100 cm 2
of surface moss; ~3 cm deep), Rhododendron groenlandicum
and Vaccinium vitis-idaea
(the topmost 3-5 leaves), Vaccinium oxycoccos
(aboveground leaves and stems), Rubus chamaemorus
and Maianthemum trifolium
(leaves), and Picea mariana
(apical shoots of current year’s growth). There were five collections in 2009 (except for JPH4 which was not established as a site until 2010), and 6 collections in both 2010 and 2011, all between late May and early October.
In the laboratory, samples were cleaned to remove any debris. The topmost 1-cm of Cladonia arbuscula
was separated from lower portions of the lichen thalli and retained for analysis. Leaves/needles were separated from stems of Vaccinium oxycoccos
and Picea mariana,
with the leaves/needles retained for analysis. For the two Sphagnum
species, capitula (the top 1-cm of plants) were retained for analysis. Dried samples (at 60 °C) were ground in a Wiley Mini-mill and subsamples sent to the Southern Illinois University-Carbondale Stable Isotope Facility for 15
N analysis on a Thermo Electron Delta V Plus Isotope Ratio Mass Spectrometer. Nitrogen concentrations in lichen/plant material were determined on a Leco TruSpec® CN analyzer. Standard curves for N were constructed using differing quantities (0.1–0.2 g) of standard reference materials (for C, NIST 1632b coal, Leco 1018 tobacco leaves; for N, NIST 1547 peach leaves, NIST 1632b coal, Leco 1018 tobacco leaves; for S, NIST 1632b coal, Leco 1018 tobacco leaves). All standard curves had R 2
values > 0.999. Analyses with 0.2 g of samples had limits of detection of 0.3 mg g −1
; analyses of standard reference materials not used to construct standard curves produced N concentrations within 1.5 % of certified values.
