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
NH4
+-N (phenate
method) on a Seal AA3 Auto Analyzer and for
NO3
--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
NH4
+-N (phenate
method, Seal AA3 AutoAnalyzer),
NO3
--N and
SO4
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
NH4
+-N (phenate
method, Seal AA3 AutoAnalyzer),
NO3
--N and
SO4
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 15N
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
NO3
--N, DIN, and
SO4
2--S with
increasing distance from oil sands operations.
Deposition of
NH4
+-N,
NO3
--N, DIN
(NH4
+-N +
NO3
--N) and
SO4
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 cm2 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
15N 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
R2 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.
