1. Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake.

    Proceedings of the Royal Society B: Biological ... 283(1836) (2016) PMID 27534958

    Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed $1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large q...
  2. Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region.

    PLoS ONE 11(5):e0153987 (2016) PMID 27135946 PMCID PMC4852901

    Freshwaters in the Athabasca Oil Sands Region (AOSR) are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main developme...
  3. The jellification of north temperate lakes.

    Proceedings of the Royal Society B: Biological ... 282(1798):20142449 (2015) PMID 25411451 PMCID PMC4262185

    Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic ...
  4. The bias and signal attenuation present in conventional pollen-based climate reconstructions as assessed by early climate data from Minnesota, USA.

    PLoS ONE 10(1):e0113806 (2015) PMID 25602619 PMCID PMC4300216

    The inference of past temperatures from a sedimentary pollen record depends upon the stationarity of the pollen-climate relationship. However, humans have altered vegetation independent of changes to climate, and consequently modern pollen deposition is a product of landscape disturbance and cli...
  5. Industrial arsenic contamination causes catastrophic changes in freshwater ecosystems.

    Scientific reports 5:17419 (2015) PMID 26615891 PMCID PMC4663503

    Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is kn...
  6. Climate change forces new ecological states in tropical Andean lakes.

    PLoS ONE 10(2):e0115338 (2015) PMID 25647018 PMCID PMC4315470

    Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, ...
  7. Tracking the History and Ecological Changes of Rising Double-Crested Cormorant Populations Using Pond Sediments from Islands in Eastern Lake Ontario.

    PLoS ONE 10(7):e0134167 (2015) PMID 26214177 PMCID PMC4516326

    In the Laurentian Great Lakes region, the double-crested cormorant (Phalacrocorax auritus) has seen a thousand-fold population increase in recent decades. These large colonies of birds now often conflict with socioeconomic interests, particularly due to perceived competition with fisheries and t...
  8. Determining diatom ecotones and their relationship to terrestrial ecoregion designations in the central Canadian Arctic Islands.

    Journal of Phycology 50(4):610 (2014) PMID 26988446

    Ecotones are key areas for the detection of global change because many are predicted to move with shifts in climate. Prince of Wales Island, in the Canadian Arctic Archipelago, spans the transition between mid- to high-Arctic ecoregions. We analyzed limnological variables and recent diatom assem...
  9. Dissolved organic carbon thresholds affect mercury bioaccumulation in Arctic lakes.

    Environmental Science & Technology 48(6):3162 (2014) PMID 24524759

    Dissolved organic carbon (DOC) is known to affect the Hg cycle in aquatic environments due to its overriding influence on complexation, photochemical, and microbial processes, but its role as a mediating factor in the bioaccumulation of Hg in aquatic biota has remained enigmatic. Here, we examin...
  10. Reply to Hrudey: Tracking the extent of oil sands airborne pollution.

    PNAS 110(30):E2749 (2013) PMID 24044119 PMCID PMC3725053

  11. Comparison of Freshwater Diatom Assemblages from a High Arctic Oasis to Nearby Polar Desert Sites and Their Application to Environmental Inference Models.

    Journal of Phycology 49(1):41 (2013) PMID 27008387

    Arctic oases are regions of atypical warmth and relatively high biological production and diversity. They are small in area (<5 km(2) ) and uncommon in occurrence, yet they are relatively well studied due to the abundance of plant and animal life contained within them. A notable exception is the...
  12. Legacy of a half century of Athabasca oil sands development recorded by lake ecosystems.

    PNAS 110(5):1761 (2013) PMID 23297215 PMCID PMC3562817

    The absence of well-executed environmental monitoring in the Athabasca oil sands (Alberta, Canada) has necessitated the use of indirect approaches to determine background conditions of freshwater ecosystems before development of one of the Earth's largest energy deposits. Here, we use highly res...
  13. Exploratory hydrocarbon drilling impacts to Arctic lake ecosystems.

    PLoS ONE 8(11):e78875 (2013) PMID 24223170 PMCID PMC3819393

    Recent attention regarding the impacts of oil and gas development and exploitation has focused on the unintentional release of hydrocarbons into the environment, whilst the potential negative effects of other possible avenues of environmental contamination are less well documented. In the hydroc...
  14. Spatial and temporal assessment of mercury and organic matter in thermokarst affected lakes of the Mackenzie Delta uplands, NT, Canada.

    Environmental Science & Technology 46(16):8748 (2012) PMID 22839429

    We examined dated sediment cores from 14 thermokarst affected lakes in the Mackenzie Delta uplands, NT, Arctic Canada, using a case-control analysis to determine how retrogressive thaw slump development from degrading permafrost affected the delivery of mercury (Hg) and organic carbon (OC) to la...
  15. Historical pesticide applications coincided with an altered diet of aerially foraging insectivorous chimney swifts.

    Proceedings of the Royal Society B: Biological ... 279(1740):3114 (2012) PMID 22513860 PMCID PMC3385487

    Numerous environmental pressures have precipitated long-term population reductions of many insect species. Population declines in aerially foraging insectivorous birds have also been detected, but the cause remains unknown partly because of a dearth of long-term monitoring data on avian diets. C...
  16. ABSENCE OF EVIDENCE IS NOT EVIDENCE OF ABSENCE: IS STEPHANODISCUS BINDERANUS (BACILLARIOPHYCEAE) AN EXOTIC SPECIES IN THE GREAT LAKES REGION?(1).

    Journal of Phycology 48(2):270 (2012) PMID 27009716

    The eutrophic, freshwater diatom species Stephanodiscus binderanus (Kütz.) Willi Krieg. has long been considered a nuisance exotic alga introduced from Eurasia to the Great Lakes in North America in the early to mid-20th century. However, our paleolimnological data from Lake Simcoe, Ontario, pro...
  17. Anomalous rise in algal production linked to lakewater calcium decline through food web interactions.

    Proceedings of the Royal Society B: Biological ... 279(1731):1210 (2012) PMID 21957138 PMCID PMC3267133

    Increased algal blooms are a threat to aquatic ecosystems worldwide, although the combined effects of multiple stressors make it difficult to determine the underlying causes. We explore whether changes in trophic interactions in response to declining calcium (Ca) concentrations, a water quality ...
  18. Q&A: Regime change. Interview by Hannah Hoag.

    Nature 483(7387):S16 (2012) PMID 22378121

  19. Climate Change: A planet in flux.

    Nature 483(7387):S12 (2012) PMID 22378120

  20. Effects of seabird vectors on the fate, partitioning, and signatures of contaminants in a High Arctic ecosystem.

    Environmental Science & Technology 45(23):10053 (2011) PMID 22026353

    Seabirds bioaccumulate contaminants from prey, transport them to their nesting sites, and deposit them in their excreta and carcasses, thereby focusing marine-derived contaminants into remote, terrestrial receptor sites. In the case of organochlorine chemicals transported by northern fulmars (Fu...