Are bog plant/lichen tissue concentrations of Ca, Mg, K, and P affected by fugitive dust released from oil sands development in the Fort McMurray region of Alberta?

Bogs are ombrotrophic, relying solely on atmospheric deposition for new inputs of elements. Increased element deposition through anthropogenic activities has the potential to alter nutrient availability, and hence ecosystem function, in bogs. Further, because of efficient element retention, bogs may function as effective monitors of element deposition. To assess the potential effects of particulate fugitive dust from oil sands development in Alberta, Canada, we quantified plant/lichen tissue Ca, Mg, K, and P concentrations in 6 bogs ranging from 12 to 77 km from the oil sands industrial center. Deposition of Ca and Mg, but not K or P, quantified using ion exchange resin collectors, to bogs decreased with distance from the oil sands industrial center. Concentrations of Ca and Mg, but not K or P, in tissues of lichens (Cladonia mitis, Evernia mesomorpha) and Sphagnum (S. capillifolium, S. fuscum) decreased with distance from the oil sands industrial center. Tissue Ca concentrations were positively correlated with growing season Ca and Mg deposition in all species except Vaccinium oxycoccos, Rhododendron groenlandicum, and Picea mariana; leaf Mg concentrations were positively correlated with growing season Mg deposition for all species except P. mariana. Tissue concentrations of K and P were not correlated with growing season K and P deposition. For each species, receptor modeling identified two distinct sources, one dominated by Ca and Mg, presumed to represent particulate fugitive dust from oil sands activities, and a second dominated by K and P, which may reflect tight internal cycling and upward translocation of K and P in peat and/or K and P deposition as particulates generated in wildfires. Increasing Ca2+ and Mg2+ deposition may acidify bog porewaters through cation exchange in peat.

Is bog water chemistry affected by increasing N and S deposition from oil sands development in Northern Alberta, Canada?

Nitrogen and sulfur emissions from oil sands operations in northern Alberta, Canada have resulted in increasing deposition of N and S to the region's ecosystems. To assess whether a changing N and S deposition regime affects bog porewater chemistry, we sampled bog porewater at sites at different distances from the oil sands industrial center from 2009 to 2012 (10-cm intervals to a depth of 1 m) and from 2009 to 2019 (top of the bog water table only). We hypothesized that: (1) as atmospheric N and S deposition increases with increasing proximity to the oil sands industrial center, surface porewater concentrations of NH4+, NO3-, DON, and SO42- would increase and (2) with increasing N and S deposition, elevated porewater concentrations of NH4+, NO3-, DON, and SO42- would be manifested increasingly deeper into the peat profile. We found weak evidence that oil sands N and S emissions affect bog porewater NH4+-N, NO3--N, or DON concentrations. We found mixed evidence that increasing SO42- deposition results in increasing porewater SO42- concentrations. Current SO42- deposition, especially at bogs closest to the oil sands industrial center, likely exceeds the ability of the Sphagnum moss layer to retain S through net primary production, such that atmospherically deposited SO42- infiltrates downward into the peat column. Increasing porewater SO42- availability may stimulate dissimilatory sulfate reduction and/or inhibit CH4 production, potentially affecting carbon cycling and gaseous fluxes in these bogs.

Bog plant/lichen tissue nitrogen and sulfur concentrations as indicators of emissions from oil sands development in Alberta, Canada.

Increasing gaseous emissions of nitrogen (N) and sulfur (S) associated with oil sands development in northern Alberta (Canada) has led to changing regional wet and dry N and S deposition regimes. We assessed the potential for using bog plant/lichen tissue chemistry (N and S concentrations, C:N and C:S ratios, in 10 plant/lichen species) to monitor changing atmospheric N and S deposition through sampling at five bog sites, 3-6 times per growing season from 2009 to 2016. During this 8-year period, oil sands N emissions steadily increased, while S emissions steadily decreased. We examined the following: (1) whether each species showed changes in tissue chemistry with increasing distance from the Syncrude and Suncor upgrader stacks (the two largest point sources of N and S emissions); (2) whether tissue chemistry changed over the 8 year period in ways that were consistent with increasing N and decreasing S emissions from oil sands facilities; and (3) whether tissue chemistry was correlated with growing season wet deposition of NH4+-N, NO3--N, or SO42--S. Based on these criteria, the best biomonitors of a changing N deposition regime were Evernia mesomorpha, Sphagnum fuscum, and Vaccinium oxycoccos. The best biomonitors of a changing S deposition regime were Evernia mesomorpha, Cladonia mitis, Sphagnum fuscum, Sphagnum capillifolium, Vaccinium oxycoccos, and Picea mariana. Changing N and S deposition regimes in the oil sands region appear to be influencing N and S cycling in what once were pristine ombrotrophic bogs, to the extent that these bogs may effectively monitor future spatial and temporal patterns of deposition.

Experimental nitrogen addition alters structure and function of a boreal poor fen: Implications for critical loads.

Bogs and fens cover 6 and 21%, respectively, of the 140,329 km2 Oil Sands Administrative Area in northern Alberta. Regional background atmospheric N deposition is low (<2 kg N ha-1 yr-1), but oil sands development has led to increasing N deposition (as high as 17 kg N ha-1 yr-1). To examine responses to N deposition, over five years, we experimentally applied N (as NH4NO3) to a poor fen near Mariana Lake, Alberta, unaffected by oil sands activities, at rates of 0, 5, 10, 15, 20, and 25 kg N ha-1 yr-1, plus controls (no water or N addition). At Mariana Lake Poor Fen (MLPF), increasing N addition: 1) progressively inhibited N2-fixation; 2) had no effect on net primary production (NPP) of Sphagnum fuscum or S. angustifolium, while stimulating S. magellanicum NPP; 3) led to decreased abundance of S. fuscum and increased abundance of S. angustifolium, S. magellanicum, Andromeda polifolia, Vaccinium oxycoccos, and of vascular plants in general; 4) led to an increase in stem N concentrations in S. angustifolium and S. magellanicum, and an increase in leaf N concentrations in Chamaedaphne calyculata, Andromeda polifolia, and Vaccinium oxycoccos; 5) stimulated root biomass and production; 6) stimulated decomposition of cellulose, but not of Sphagnum or vascular plant litter; and 7) had no or minimal effects on net N mineralization in surface peat, NH4+-N, NO3--N or DON concentrations in surface porewater, or peat microbial composition. Increasing N addition led to a switch from new N inputs being taken up primarily by Sphagnum to being taken up primarily by shrubs. MLPF responses to increasing N addition did not exhibit threshold triggers, but rather began as soon as N additions increased. Considering all responses to N addition, we recommend a critical load for poor fens in Alberta of 3 kg N ha-1 yr-1.

Retraction Statement: Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N2 -fixation in Central European peatlands despite decades of atmospheric N pollution.

"Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N2 -fixation in Central European peatlands despite decades of atmospheric N pollution" https://doi.org/10.1111/gcb.14505, by Martin Novak, Melanie A. Vile, Jan Curik, Bohuslava Cejkova, Jiri Barta, Marketa Stepanova, Ivana Jackova, Frantisek Buzek, Leona Bohdalkova, Eva Prechova, Frantisek Veselovsky, Marie Adamova, Ivana Valkova and Arnost Komarek. The above article, first published online in Wiley Online Library (wileyonlinelibrary.com) in Global Change Biology, has been retracted by agreement between the authors, the journal Editor-in-Chief, Stephen P. Long, and John Wiley & Sons Ltd. Since publication of the above article, it was brought to the attention of the authors that the peat accretion rates violate reasonable ranges of peatland C/N/P stoichiometry, placing the quantitative conclusions of the article in serious error. The authors apologize for any inconvenience the publication of this work may have caused our readers. REFERENCE Novak, M., Vile, M. A., Cejkova, B., Barta, J., Stepanova, M., Jackova, I., Buzek, F., Bohdalkova, L., Prechova, E., Veselovsky, F., Adamova, M., Valkova, I., & Komarek, A. (2018). Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N2 -fixation in Central European peatlands despite decades of atmospheric N pollution. Global Change Biology.. https://doi.org/10.1111/gcb.14505.

Differential Effects of High Atmospheric N and S Deposition on Bog Plant/Lichen Tissue and Porewater Chemistry across the Athabasca Oil Sands Region.

Oil extraction and development activities in the Athabasca Oil Sands Region of northern Alberta, Canada, release NOx, SOx, and NHy to the atmosphere, ultimately resulting in increasing N and S inputs to surrounding ecosystems through atmospheric deposition. Peatlands are a major feature of the northern Alberta landscape, with bogs covering 6-10% of the land area, and fens covering 21-53%. Bulk deposition of NH4+-N, NO3--N, dissolved inorganic N (DIN), and SO42--S, was quantified using ion-exchange resin collectors deployed at 23 locations, over 1-6 years. The results reveal maximum N and S deposition of 9.3 and 12.0 kg ha-1 yr-1, respectively, near the oil sands industrial center (the midpoint between the Syncrude and Suncor upgrader stacks), decreasing with distance to a background deposition of 0.9 and 1.1 kg ha-1 yr-1, respectively. To assess potential influences of high N and S deposition on bogs, we quantified N and S concentrations in tissues of two Sphagnum species, two lichen species, and four vascular plant species, as well as surface porewater concentrations of H+, NH4+-N, NO3--N, SO42--S and dissolved organic N in 19 ombrotrophic bogs, distributed across a 3255 km2 sampling area surrounding the oil sands industrial center. The two lichen species (Evernia mesomorpha and Cladonia mitis), two vascular plant species (Rhododendron groenlandicum and Picea mariana), and to a lesser extent one moss (Sphagnum fuscum), showed patterns of tissue N and S concentrations that were (1) highest near the oil sands industrial center and (2) positively correlated with bulk deposition of N or S. Concentrations of porewater H+ and SO42--S, but not of NH4+-N, NO3--N, DIN, or dissolved inorganic N, also were higher near the oil sands industrial center than at more distant locations. The oil sands region of northern Alberta is remote, with few roads, posing challenges to the monitoring of oil sands-related N and S deposition. Quantification of N and S concentrations in bog plant/lichen tissues and porewaters may serve as a monitoring tool to assess both the local intensity and the spatial extent of bulk N and S deposition, and as harbingers of potential shifts in ecosystem structure and function.

Ecological restoration of rich fens in Europe and North America: from trial and error to an evidence-based approach.

Fens represent a large array of ecosystem services, including the highest biodiversity found among wetlands, hydrological services, water purification and carbon sequestration. Land-use change and drainage has severely damaged or annihilated these services in many parts of North America and Europe; restoration plans are urgently needed at the landscape level. We review the major constraints on the restoration of rich fens and fen water bodies in agricultural areas in Europe and disturbed landscapes in North America: (i) habitat quality problems: drought, eutrophication, acidification, and toxicity, and (ii) recolonization problems: species pools, ecosystem fragmentation and connectivity, genetic variability, and invasive species; and here provide possible solutions. We discuss both positive and negative consequences of restoration measures, and their causes. The restoration of wetland ecosystem functioning and services has, for a long time, been based on a trial-and-error approach. By presenting research and practice on the restoration of rich fen ecosystems within agricultural areas, we demonstrate the importance of biogeochemical and ecological knowledge at different spatial scales for the management and restoration of biodiversity, water quality, carbon sequestration and other ecosystem services, especially in a changing climate. We define target processes that enable scientists, nature managers, water managers and policy makers to choose between different measures and to predict restoration prospects for different types of deteriorated fens and their starting conditions.

Sphagnum mosses from 21 ombrotrophic bogs in the athabasca bituminous sands region show no significant atmospheric contamination of "heavy metals".

Sphagnum moss was collected from 21 ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca bituminous sands in Alberta (AB). In comparison to contemporary Sphagnum moss from four bogs in rural locations of southern Germany (DE), the AB mosses yielded lower concentrations of Ag, Cd, Ni, Pb, Sb, and Tl, similar concentrations of Mo, but greater concentrations of Ba, Th, and V. Except for V, in comparison to the "cleanest", ancient peat samples ever tested from the northern hemisphere (ca. 6000-9000 years old), the concentrations of each of these metals in the AB mosses are within a factor of 3 of "natural, background" values. The concentrations of "heavy metals" in the mosses, however, are proportional to the concentration of Th (a conservative, lithophile element) and, therefore, contributed to the plants primarily in the form of mineral dust particles. Vanadium, the single most abundant trace metal in bitumen, is the only anomaly: in the AB mosses, V exceeds that of ancient peat by a factor of 6; it is therefore enriched in the mosses, relative to Th, by a factor of 2. In comparison to the surface layer of peat cores collected in recent years from across Canada, from British Columbia to New Brunswick, the Pb concentrations in the mosses from AB are far lower.

Microbial transformations of nitrogen, sulfur, and iron dictate vegetation composition in wetlands: a review.

The majority of studies on rhizospheric interactions focus on pathogens, mycorrhizal symbiosis, or carbon transformations. Although the biogeochemical transformations of N, S, and Fe have profound effects on vegetation, these effects have received far less attention. This review, meant for microbiologists, biogeochemists, and plant scientists includes a call for interdisciplinary research by providing a number of challenging topics for future ecosystem research. Firstly, all three elements are plant nutrients, and microbial activity significantly changes their availability. Secondly, microbial oxidation with oxygen supplied by radial oxygen loss from roots in wetlands causes acidification, while reduction using alternative electron acceptors leads to generation of alkalinity, affecting pH in the rhizosphere, and hence plant composition. Thirdly, reduced species of all three elements may become phytotoxic. In addition, Fe cycling is tightly linked to that of S and P. As water level fluctuations are very common in wetlands, rapid changes in the availability of oxygen and alternative terminal electron acceptors will result in strong changes in the prevalent microbial redox reactions, with significant effects on plant growth. Depending on geological and hydrological settings, these interacting microbial transformations change the conditions and resource availability for plants, which are both strong drivers of vegetation development and composition by changing relative competitive strengths. Conversely, microbial composition is strongly driven by vegetation composition. Therefore, the combination of microbiological and plant ecological knowledge is essential to understand the biogeochemical and biological key factors driving heterogeneity and total (i.e., microorganisms and vegetation) community composition at different spatial and temporal scales.

Origin of lead in eight Central European peat bogs determined from isotope ratios, strengths, and operation times of regional pollution sources.

Lead originating from coal burning, gasoline burning, and ore smelting was identified in 210Pb-dated profiles through eight peat bogs distributed over an area of 60,000 km2. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering with Germany, Austria, and Poland. Basal peat 14C-dated at 11,000 years BP had a relatively high 206Pb/207Pb ratio (1.193). Peat deposited around 1800 AD had a lower 206Pb/207Pb ratio of 1.168-1.178, indicating that environmental lead in Central Europe had been largely affected by human activity (smelting) even before the beginning of the Industrial Revolution. Five of the sites exhibited a nearly constant 206Pb/207Pb ratio (1.175) throughout the 19th century, resembling the "anthropogenic baseline" described in Northern Europe (1.17). At all sites, the 206Pb/207Pb ratio of peat decreased at least until 1980; at four sites, a reversal to more radiogenic values (higher 206Pb/207Pb), typical of easing pollution, was observed in the following decade (1980-1990). A time series of annual outputs for 14 different mining districts dispersing lead into the environment has been constructed for the past 200 years. The production of Ag-Pb, coal, and leaded gasoline peaked in 1900, 1980, and 1980, respectively. In contrast to other European countries, no peak in annual Pb accumulation rates was found in 1900, the year of maximum ore smelting. The highest annual Pb accumulation rates in peat were consistent with the highest Pb emission rates from coal-fired power plants and traffic (1980). Although maximum coal and gasoline production coincided in time, their isotope ratios were unique. The mean measured 206Pb/207Pb ratios of local coal, ores, and gasoline were 1.19, 1.16, and 1.11, respectively. A considerable proportion of coal emissions, relative to gasoline emisions, was responsible for the higher 206Pb/207Pb ratios in the recent atmosphere (1.15) compared to Western Europe (1.10). As in West European countries, the gasoline sold in the Czech Republic during the Communist era (1948-1989) contained an admixture of low-radiogenic Precambrian lead from Australia.