The extraction and upgrading of bitumen have been identified as sources of enhanced atmospheric deposition of pollutant elements to ecosystems in the Athabasca Oil Sands Region (AOSR) in northern Alberta, Canada. Bitumen extraction became increasingly efficient, and oil prices surged in the 1990s, resulting in rapid expansion and increased production over the last two decades. Here, we examine temporal and spatial trends in wintertime atmospheric deposition of pollutant elements in 1978, 1981, 2008, and 2011–2016 at broad spatial scales using snowpack measurements. A hybrid source analysis was conducted, including (i) simple and multiple linear regression (MLR) of identified source locations and elemental deposition, (ii) spatially resolved aluminum enrichment factors (Al EFs), and (iii) positive matrix factorization (PMF) to determine source profiles. Temporal trends revealed a general decrease in atmospheric loadings; however, near-field V, Ti, and Al loadings in 2016 were an order of magnitude greater ...

We examined the influence of biological and geographical factors on the levels and patterns of organohalogen contaminants in blood of adult common loons (Gavia immer) collected from 20 lakes in Alberta, Canada. The loons were captured in the 2006 and 2007 breeding seasons over a 900 m elevation gradient across the eastern slope of the Canadian Rocky Mountains. While PCBs dominated the composition of these contaminants in loons at all sites (∑PCBs > p,p'-DDE > ∑PBDEs > ∑Chlordanes > HCB), p,p'-DDE and ∑PBDEs were also important, averaging approximately 50% and 20% of total PCB concentrations, respectively. ∑PCBs and ∑PBDEs were higher in males than in females. Inter-lake variation was apparent for contaminant concentrations and patterns and were largely explained by dietary signatures (δ15N and δ13C) and proximity to a large hydroelectric dam. Mean ∑PCB (19.6 ng/g wet weight (ww)) and organochlorine pesticide (OCP) (p,p'-DDE: 11.8 ng/g, cis-nonachlor: 0.10 ng/g, trans-nonachlor: 0.32 ng/g, HCB: 0.34 ng/g ww) concentrations in loons were approximately 4- to 17-fold lower than average concentrations reported in common loons from Atlantic Canada and were well below concentrations which have been associated with impaired reproductive success and eggshell thinning in other piscivorous birds. Dominant PBDE congeners were BDE47, BDE99, and BDE100. The regional mean for ∑PBDEs (4.04 ng/g ww) in loons from the present study was within the range reported for ∑PBDEs in nestling bald eagle plasma from British Columbia. This is the first report of PBDEs in loons and the first report of PCBs and OCPs in common loons from Western North America.

A whole-ecosystem experiment in Lake 227 (L227) at the Experimental Lakes Area, ongoing since 1969, examined the roles of carbon (C), nitrogen (N), and phosphorus (P) in controlling eutrophication. During 2011, we conducted a series of sub-experiments and more intensive monitoring to improve estimates of N fixation and its ability to meet algal growth demands in the decades following the cessation of artificial N loading, while maintaining long-term high artificial P loading. Stoichiometric nutrient ratios indicated both moderate N and P limitation of the phytoplankton during spring, preceding a shift in phytoplankton community structure toward dominance by N fixing cyanobacteria. During bloom development, and for the remainder of the stratified period, stoichiometric nutrient ratios indicated moderate to strong P limitation. N fixation rates, corrected using 15N2 methods, increased 2× after 1990, when N loading ceased. Ambient dissolved inorganic nitrogen prior to the bloom represented less than 3% of N demands of the phytoplankton. N fixation accounted for between 69–86% of total N loading to the epilimnion during the period of rapid bloom development, and 72–86% of total N loading during the May–October period. Phytoplankton biomass did not decline in L227 during the 40 years since artificial N loading was reduced, or the nearly 25 years since artificial N loads ceased entirely (1990–2013), and remained approximately 20× higher than four nearby reference lakes. These results suggest that despite constraints on biological N fixation, it retains a large capacity to offset potential N loading reductions in freshwaters.

ADVERTISEMENT RETURN TO ISSUEPREVLetter to the EditorNEXTResponse to the Letter, Nitrogen is Not a "House of Cards"D. W. Schindler*, S. R. Carpenter, S. C. Chapra, R. E. Hecky, and D. M. OrihelCite this: Environ. Sci. Technol. 2017, 51, 4, 1943Publication Date (Web):January 5, 2017Publication History Received9 December 2016Accepted11 December 2016Published online5 January 2017Published inissue 21 February 2017https://pubs.acs.org/doi/10.1021/acs.est.6b06106https://doi.org/10.1021/acs.est.6b06106article-commentaryACS PublicationsCopyright © 2017 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views1010Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (125 KB) Get e-AlertscloseSUBJECTS:Environmental pollution,Nitrogen Get e-Alerts

Atmospheric deposition of polycyclic aromatic compounds (PACs) via and onto snow, and their releasing during spring snowmelt has been a concern in the Athabasca Oil Sands Region of Alberta. This study was designed to evaluate the concentrations, loadings, and distribution of PACs in springtime snowpack and how they have changed since the first study in 2008. Snowpack samples were collected in late winters 2011–2014 at varying distances from the main developments. PAC concentration and deposition declined exponentially with distance, with pyrenes, chrysenes, and dibenzothiophenes dominating the distribution within the first 50 km. The distribution of PACs was different between sites located close to upgraders and others located close to mining facilities. Overall, PAC loadings were correlated with priority pollutant elements and water chemistry parameters, while wind direction and speed were not strong contributors to the variability observed. Total PAC mass deposition during winter months and within the first 50 km was initially estimated by integrating the exponential decay function fitted through the data using a limited number of sites from 2011 to 2014: 1236 kg (2011), 1800 kg (2012), 814 kg (2013), and 1367 (2014). Total loadings were estimated to have a twofold increase between 2008 and 2014, although the increase observed was not constant. Finally, kriging interpolation is presented as an alternative and more robust approach to estimate PAC mass deposition in the area. After a more intensive sampling campaign in 2014, the PAC mass deposition was estimated to be 1968 kg.

The effects of reducing nutrient inputs to lakes and reservoirs are often delayed by hysteresis resulting from internal phosphorus (P) loading from sediments. Consequently, controlling harmful algal blooms (HABs) in many eutrophic ecosystems requires additional management to improve water quality. We manipulated iron (Fe) concentrations in a hypereutrophic lake to determine if Fe amendment would suppress HABs by inhibiting P release from sediments. Our experiment consisted of 15 in situ mesocosms, 12 of which each received a different dose of Fe (ranging from 2 to 225 g/m2 ); the remaining three were unmanipulated to serve as controls. Iron amendment decreased P accumulation in porewaters and the flux of P from sediments, which significantly lowered P concentrations in the water column. Iron exerted significant dose-dependent negative effects on the biomass of phytoplankton and periphyton, and reduced the dominance of cyanobacteria. Even at the lowest doses, Fe appeared to reduce the toxicity of cyanobacterial blooms, as measured by concentrations of hepatotoxic microcystins. Overall, our findings highlight the potential for Fe treatment as an effective strategy for minimizing HABs in eutrophic lakes and reservoirs. More broadly, our study reinforces the importance of Fe in regulating the trophic state of freshwaters, and the sensitivity of certain ecosystems to changes in Fe supply. Finally, we hypothesize that decreases in natural Fe supplies to lakes associated with anthropogenic activities may worsen outbreaks of toxic cyanobacteria.

As human populations increase and land-use intensifies, toxic and unsightly nuisance blooms of algae are becoming larger and more frequent in freshwater lakes. In most cases, the blooms are predominantly blue-green algae (Cyanobacteria), which are favored by low ratios of nitrogen to phosphorus. In the past half century, aquatic scientists have devoted much effort to understanding the causes of such blooms and how they can be prevented or reduced. Here we review the evidence, finding that numerous long-term studies of lake ecosystems in Europe and North America show that controlling algal blooms and other symptoms of eutrophication depends on reducing inputs of a single nutrient: phosphorus. In contrast, small-scale experiments of short duration, where nutrients are added rather than removed, often give spurious and confusing results that bear little relevance to solving the problem of cyanobacteria blooms in lakes.

Expansion of the oil sands industry in Canada has caused land destruction and social friction. Canada could become a leader in climate governance by honouring treaty commitments made with indigenous peoples.

We applaud Mackey et al.'s (2014) recent piece in Conservation Letters (Policy Options for the World's Primary Forests in Multilateral Environmental Agreements) that highlights the lack of international recognition of the critical importance of the world's primary forests. These last, remaining forests that are free of large-scale industrial development are desperately in need of a focused effort to protect them from future loss and degradation. Mackey et al.'s focus on multilateral environmental agreements, however, may provide an incomplete outlook on the full range of opportunities to best achieve protection of the world's primary forests. International treaties and other policy instruments can certainly be incredibly important in providing incentives or disincentives, increasing funding support, and providing novel economic mechanisms to achieve further protections of primary forests. However, as Mackey et al. point out, about half of the world's remaining primary forests are found in five developed countries (Canada, United States, Russia, Australia, and New Zealand). We contend that conservation opportunities in at least some of these nations are currently most effectively pursued by focusing on domestic policy options. Canada, for example, holds an estimated 25% of the world's remaining primary forest within its Boreal Forest region—an area of approximately 5.6 million km2. The region stores a minimum of 208 billion tons of carbon (Carlson et al. 2009) and supports some of the world's largest populations of northern large mammals including some that undertake large-scale annual migrations, a phenomena lost in much of the world (Bradshaw et al. 2009; IBCSP 2013; Wells et al. 2013). The region is estimated to support between one and three billion nesting birds, most of which migrate south to populate temperate and tropical ecological communities (Wells & Blancher 2011). Importantly, Canada's Boreal Forest region is home to hundreds of indigenous communities where the inhabitants still maintain their cultural traditions including extensive use of native fish and wildlife for food. Management decisions about the use of these lands generally now sit with provincial governments and indigenous governments. In the last 15 years, more than 870,000 km2 of new protected areas have been established across Canada's Boreal Forest region. The provinces of Quebec and Ontario, which are each larger than about 90% of the world's nations, are actively moving toward official conservation goals that together would result in an additional 858,000 km2 of primary forest becoming strictly protected (IUCN categories I–IV). Indigenous governments throughout Canada's Boreal Forest region have been particularly effective in moving forward protections for primary forest through their own initiatives. In the Northwest Territories, indigenous governments have carried out leading-edge land-use planning that has led to the development of over 425,000 km2 of protected areas and interim protected areas. In Manitoba and Ontario, five indigenous governments working collectively with provincial government, have protected 30,000 km2 of primary forest within an area they call Pimachiowin Aki. In Australia, although not focused on forest habitats, indigenous conservation efforts are also impressive with the area of land in Indigenous Protected Areas increasing from 568 km2 in 1998 to 500,347 km2 in 2014 (Woinarski et al. 2014). One of the more innovative and promising innovations in Australia is that of indigenous ranger programs that now involve more than 700 indigenous rangers in various environmental land management activities across at least 35 Indigenous Protected Areas (Woinarski et al. 2014). Efforts to protect the world's primary forests and other intact habitats through changes to international multilateral agreements are vitally important, but in some countries the most substantial on-the-ground results will likely be achieved through efforts instead focused on domestic policy options.

Several lines of evidence from a eutrophic lake show how polymixis enables phosphorus (P) released from anoxic, iron (Fe)-poor sediments to lower nitrogen-to-phosphorus (N : P) ratios and stimulate cyanobacterial blooms. Detailed sediment analyses revealed extensive formation of Fe sulfides, which suppressed porewater Fe levels and prevented sequestration of P in Fe minerals. Experimental additions of Fe significantly decreased the flux of dissolved P from warm, anoxic sediments, increasing N : P ratios in porewater and overlying water. The net midsummer effect of polymixis and P release from Fe-poor sediments quickly doubled the total P in the euphotic zone during a period of very low external P loading. This internal nutrient pump decreased N : P in surface waters and led to a cyanobacterial bloom comprised primarily of diazotrophic Anabaena and Aphanizomenon spp. along with nonheterocystous and potentially toxic Microcystis icthyoblabe and Woronichinia naegelianum. Concentrations of the cyanotoxin, microcystin, in this lake were typically elevated during, or shortly after, episodes of internal P loading. Our study demonstrates an important mechanism underlying the increasing cyanobacterial dominance of weakly stratified eutrophic north temperate lakes, and warns of further increases under a warming climate.

Summary We tested the hypothesis that higher temperature and dissolved organic carbon (DOC) concentration increase dissolved and particulate carbon (C) relative to phosphorus (P), thereby reducing algal food quality for P‐limited cladocerans while not affecting N‐limited copepods. Also, we expected alpine zooplankton to respond more strongly than those from warmer montane lakes to increased water temperature. Plankton from two alpine lakes and two montane lakes were incubated in vitro for 30 days at 10 or 17 °C and with ambient or +80% DOC, which was achieved by concentrating humic substances from each lake via reverse osmosis. Dissolved organic carbon amendments and warming significantly increase particulate C : P under montane, but not alpine conditions. While higher water temperature and DOC separately reduced phytoplankton abundance, together they increased phytoplankton by stimulating uptake of P. Warming stimulated only Daphnia while suppressing the abundance of the calanoid copepod Hesperodiaptomus when they originated from the three coldest lakes. Particulate C : P was positively correlated with Daphnia abundance and negatively correlated with Hesperodiaptomus, probably due to greater P‐retention by Daphnia. Our findings highlight the importance of interactions between the ecological effects of higher temperature and increased inputs of terrestrial organic matter to forecasts of the net impact of global warming on mountain lakes. Such predictions may be confounded if they are derived solely from the expected sum of single effects by each climatic factor.

Parajulee and Wania (1) make an important contribution to understanding the origin and magnitude of pollution caused by the massive oil sands industry in northeastern Alberta. Until recently, the oil sands industry and government officials have claimed that all pollutants carried by the lower Athabasca River system were the result of soil erosion, forest fires, and other natural phenomena. This claim was challenged by two earlier papers in PNAS (2, 3), which showed that the oil sands industry contributed substantial amounts of organic and inorganic pollutants to the watershed and river. Although these conclusions were first denied by industry and governments, expert panels appointed by provincial and federal governments supported the results, concluding that industry’s and government’s monitoring programs were incapable of assessing the extent of the pollution problem (4, 5). As a result, monitoring of the river was greatly upgraded by Environment Canada (6).

The International Boreal Conservation Science Panel (IBCSP) is an interdisciplinary team of scientists from the United States and Canada. Its members have a wide range of expertise and experience gained from years of research, conservation, and writing about science issues related to North America and many other parts of the world. The panel is jointly concerned with the future of North America’s boreal forest and in ensuring that the scientific issues related to the conservation of the boreal forest are clearly articulated to the public and decision makers in government and industry. The panel enlists its member specialists and invited expert associates in producing science/ policy briefing notes for issues of major relevance to the future of the boreal forest.

The International Boreal Conservation Science Panel (IBCSP) is an interdisciplinary team of scientists from the United States and Canada. Its members have a wide range of expertise and experience gained from years of research, conservation, and writing about science issues related to North America and many other parts of the world. The panel is jointly concerned with the future of North America’s boreal forest and in ensuring that the scientific issues related to the conservation of the boreal forest are clearly articulated to the public and decision makers in government and industry. The panel enlists its member specialists and invited expert associates in producing science/ policy briefing notes for issues of major relevance to the future of the boreal forest.

I summarize the controversies about industrial pollutants in freshwaters near the oil sands industrial area of Alberta, the inadequacies in environmental monitoring that have led to widespread misconceptions, and recent attempts to correct the problems. Adequate data are available to show that mercury, other trace metals, and polycyclic aromatic compounds are being added by industry to the Athabasca river system and its watershed, although the relative contributions of industrial development and natural sources remain in question. Recent improvements in water monitoring by Environment Canada show promise of resolving the controversies, although independent governance for Canada’s and Alberta’s water monitoring programs in the lower Athabasca River will be necessary to rebuild public confidence in the data and their interpretation by government and industry. I document one success story in the Athabasca River: the elimination of dioxins from pulp mills in the mid-1990s has caused a consumption advisory for fish in the river to be repealed.SOMMAIREJe présente ci-dessous un résumé des controverses concernant les polluants industriels dans les eaux douces à proximité de la zone industrielle des sables bitumineux de l'Alberta, des lacunes dans la surveillance des milieux de vie à l’origine d’idées fausses répandues, et de récentes tentatives visant à corriger les problèmes. Des données adéquates démontrent que l’industrie ajoute du mercure et d'autres métaux traces ainsi que des composés aromatiques polycycliques dans le système fluvial de la rivière Athabasca et dans son bassin versant, bien que les contributions relatives provenant de ces activités industrielles et de sources naturelles demeurent toujours en litige. De récentes améliorations apportées au contrôle des eaux par Environnement Canada permettent d’espérer une résolution des controverses, mais l’application d’une gouvernance indépendante des programmes de contrôle de l'eau de l'Alberta du Canada dans la partie inférieure du fleuve Athabasca sera nécessaire pour rétablir la confiance de la population à l’égard des données présentées et de leur interprétation par le gouvernement et l'industrie. Je décrie l’histoire d’une intervention réussie dans la rivière Athabasca, soit l'élimination de dioxines provenant des usines de pâte du milieu des années 1990 et qui a abouti à l’abrogation d’un avis de limitation de la consommation de poisson dans la rivière.DOI: http://dx.doi.org/10.12789/geocanj.2013.40.012

I summarize the controversies about industrial pollutants in freshwaters near the oil sands industrial area of Alberta, the inadequacies in environmental monitoring that have led to widespread misconceptions, and recent attempts to correct the problems. Adequate data are available to show that mercury, other trace metals, and polycyclic aromatic compounds are being added by industry to the Athabasca river system and its watershed, although the relative contributions of industrial development and natural sources remain in question. Recent improvements in water monitoring by Environment Canada show promise of resolving the controversies, although independent governance for Canada's and Alberta's water monitoring programs in the lower Athabasca River will be necessary to rebuild public confidence in the data and their interpretation by government and industry. I document one success story in the Athabasca River: the elimination of dioxins from pulp mills in the mid-1990s has caused a consumption advisory for fish in the river to be repealed.

nutrients. His group has also published several papers showing how the understanding of limnological processes and factors can contribute to better fisheries management. For example, during the last 35 years, several hundreds of sockeye salmon lakes in Canada and USA have been fertilized and stocked to enhance sockeye productivity. His work has shown that the success of these management strategies depends on the carrying capacity (density dependent or predation impacts) and consumer-driven processing of nutrients and energy. His work has also characterized and quantified the size-dependent processes of nutrients and foodweb interactions determining the patterns and efficiency of nutrient transfer to higher trophic levels and into the sediments. Some of the most significant extensions of Asit’s research have been the application of basic limnological and ecological concepts and theories to develop management techniques, tools and models for sustainable clean drinking water. Asit’s research on factors and processes regulating water quality has led to the establishment of Canada’s first NSERC Industry Research Chair on Environmental Management of Drinking Water. This program demonstrated how to manage clean and healthy water through water and watershed management, rather than relying upon treatment and disinfection. As we entered the 21st century, global communities are facing serious challenges in sustaining clean and healthy water. Microbial and chemical contamination of water results in millions of deaths on a daily basis around the world. Asit pioneered many aspects related to the concept of environmental management of drinking water, which integrates land-use management, climate variability, chemical and microbial water quality in lakes and reservoirs, treatment and disinfection of water, and public health. Traditionally, the safety of drinking water relies upon treatment and disinfection, without much attention to management of health risks through understanding and managing water quality at the source (lakes, reservoirs, river and streams). Asit’s community-based industry-university partnership program has been developing innovative and integrated scientific tools, techniques and models for sustainable clean and healthy drinking water, and his work has also contributed to policy development and education on water resources management. One of the fundamentally new tools that this program has developed is the molecular finger printing of fecal coliform bacteria (E. coli) to identify the animal sources of fecal contamination of freshwater ecosystems, which through integration into land-use and livestock management, have led to best land-use management to reduce pathogen risks from drinking water. Not surprisingly, his research on drinking water ecology has been featured in several newspapers, and he has been interviewed on regional and national TV/Radio programs. His partnerships with communities (both non-aboriginal and aboriginal) and stakeholders have been making a significant change in science-based decision-making capabilities at local and regional levels. In addition, Asit has also been an important contributor to the organization of our science, through serving a term as Secretary of ASLO, and an organizer of the two highly successful ASLO conferences in Victoria. For his contributions to solving environmental problems with sound limnological concepts, we are pleased to award Asit the 2013 ASLO Ruth Patrick Award. JOHN MARTIN AWARD: VAL SMITH Cited by David Schindler, Department of Biological Science, University of Alberta, Canada, d.schindler@ualberta.ca

The management of eutrophication has been impeded by reliance on short-term experimental additions of nutrients to bottles and mesocosms. These measures of proximate nutrient limitation fail to account for the gradual changes in biogeochemical nutrient cycles and nutrient fluxes from sediments, and succession of communities that are important components of whole-ecosystem responses. Erroneous assumptions about ecosystem processes and lack of accounting for hysteresis during lake recovery have further confused management of eutrophication. I conclude that long-term, whole-ecosystem experiments and case histories of lake recovery provide the only reliable evidence for policies to reduce eutrophication. The only method that has had proven success in reducing the eutrophication of lakes is reducing input of phosphorus. There are no case histories or long-term ecosystem-scale experiments to support recent claims that to reduce eutrophication of lakes, nitrogen must be controlled instead of or in addition to phosphorus. Before expensive policies to reduce nitrogen input are implemented, they require ecosystem-scale verification. The recent claim that the 'phosphorus paradigm' for recovering lakes from eutrophication has been 'eroded' has no basis. Instead, the case for phosphorus control has been strengthened by numerous case histories and large-scale experiments spanning several decades.