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Jules Blais

University of Ottawa | Université d'Ottawa, Biology, Faculty Member

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Université de Montréal

Nicholas Fisher

Rutgers, The State University of New Jersey

The University of Georgia

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Papers by Jules Blais

Microbial DNA records historical delivery of anthropogenic mercury

The ISME Journal, 2015

Mercury (Hg) is an anthropogenic pollutant that is toxic to wildlife and humans, but the response... more Mercury (Hg) is an anthropogenic pollutant that is toxic to wildlife and humans, but the response of remote ecosystems to globally distributed Hg is elusive. Here, we use DNA extracted from a dated sediment core to infer the response of microbes to historical Hg delivery. We observe a significant association between the mercuric reductase gene (merA) phylogeny and the timing of Hg deposition. Using relaxed molecular clock models, we show a significant increase in the scaled effective population size of the merA gene beginning~200 years ago, coinciding with the Industrial Revolution and a coincident strong signal for positive selection acting on residues in the terminal region of the mercuric reductase. This rapid evolutionary response of microbes to changes in the delivery of anthropogenic Hg indicates that microbial genomes record ecosystem response to pollutant deposition in remote regions.

Relations between lake morphometry and the presence of laminated lake sediments

Quaternary Science Reviews, 1998

In this paper we conduct an empirical test of a published equation which relates lake surface are... more In this paper we conduct an empirical test of a published equation which relates lake surface area and maximum lake depth to the presence or absence of laminated lake sediments. A 297 lake dataset from New York State and six regions in Canada, representing a number of biogeoclimatic zones, is employed. The results suggest that deeper lakes are more likely to contain laminated lake sediments than are shallower lakes. The percentage of lakes incorrectly predicted to contain laminated sediments (false positives) and that incorrectly predicted to contain massive sediments (false negatives), was much higher than that found in the study in which the original equation was developed. Its low predictive ability suggests, therefore, that in addition to lake morphometry, many other factors affect the formation and preservation of laminated sediments.

Seabird-driven shifts in Arctic pond ecosystems

Proceedings of the Royal Society B: Biological Sciences, 2009

Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients... more Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients across ecosystem boundaries, greatly enriching recipient food webs. As many of these animals biomagnify contaminants, they can also focus pollutants at toxic levels. Seabirds arguably represent the most significant biovectors of nutrients and contaminants from the ocean to the land, given their sheer numbers and global distribution. However, long-term census data on seabirds are rare. Using palaeolimnological proxies, we show that a colony of Arctic seabirds has experienced climate-induced population increases in recent decades. We then document increasing concentrations of contaminants, including polychlorinated biphenyls and cadmium, in pond sediments that are linked to biotransport by seabirds. Our findings suggest that climate-related shifts in global seabird populations will have the unexpected consequence of restructuring coastal ecosystems.

A test of the possible influence of seabird activity on the 210Pb flux in high Arctic ponds at Cape Vera, Devon Island, Nunavut: implications for radiochronology

Journal of Paleolimnology, 2008

... The seabird colony at Cape Vera is clearly transport-ing large quantities of marine-derived n... more

Impacts of seabird-derived nutrients on water quality and diatom assemblages from Cape Vera, Devon Island, Canadian High Arctic

Hydrobiologia, 2008

Allochthonous nutrient subsidies play an important role in shaping biotic communities, particular... more Allochthonous nutrient subsidies play an important role in shaping biotic communities, particularly in naturally oligotrophic ecosystems such as those commonly found in the Canadian High Arctic. Seabirds have been identified as an important vector capable of transporting significant quantities of nutrients from marine to terrestrial environments. However, the influence of seabird-derived nutrients on water quality and ecosystem functioning of Arctic freshwater systems has been largely unexplored. Here, we sampled 24 ponds on Cape Vera, Devon Island (Nunavut, Arctic Canada), an area that is home to over 10,000 nesting pairs of northern fulmars (Fulmarus glacialis), in order to explore the influence of seabirds on water quality and diatom ecology. Our data reveal distinctive water chemistry changes (e.g., high pH, nutrients) and diatom assemblages (e.g., very low diversity) related to varying degrees of bird influence. Using d 15 N as a proxy of trophic level, we show that a small but significant portion of the variance in the diatom species data can be explained by seabird-derived nutrients. Although the generation of robust quantitative models predicting d 15 N from fossil diatom data was limited by the overwhelming dominance of a few taxa, this study provides evidence that seabird-derived nutrients play a critical role in influencing the water quality of Arctic ponds. Interestingly, diatom assemblage composition does not respond in a simple fashion to seabird-derived nutrients, in contrast to diatom-nutrient relationships recorded in many temperate regions.

High Arctic Ponds Receiving Biotransported Nutrients from a Nearby Seabird Colony Are Also Subject to Potentially Toxic Loadings of Arsenic, Cadmium, and Zinc

Environmental Toxicology and Chemistry, 2009

The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients... more The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients and trace elements to a series of 10 ponds located along a gradient of seabird influence below a fulmar colony in the high Arctic (Cape Vera, Devon Island, Canada). Phosphorus, Cd, K, Zn, and As were identified as seabird-derived elements, having both a high concentration in fulmar guano and a low concentration in background pond sediments (i.e., a high biogenic enrichment factor). Fluxes of these elements were highest in the pond closest to the colony and declined exponentially with distance. Sediments in several of the ponds exceeded Canadian Sediment Quality Guidelines for the Protection of Aquatic Life set for As (5.9 mg/kg) and Cd (0.6 mg/kg), and in the pond closest to the colony, which receives the most seabird subsidies, sediments contained 343 mg/kg Zn, exceeding the threshold for probable adverse biological effects. Although nutrient subsidies from fulmars create an Arctic oasis at Cape Vera, which supports a variety of flora and fauna, the same biological transport pathway puts at risk some of these species by creating sedimentary As, Cd, and Zn concentrations at this remote site similar to those usually observed only near industrialized locations.

The cultural eutrophication of Lac la Biche, Alberta, Canada: a paleoecological study

Canadian Journal of Fisheries and Aquatic Sciences, 2008

A multiproxy paleoecological investigation of Lac la Biche, a large boreal lake in northeastern A... more A multiproxy paleoecological investigation of Lac la Biche, a large boreal lake in northeastern Alberta, Canada, revealed that the lake was eutrophic before European settlement but has undergone additional cultural eutrophication in the past 30 to 50 years. Annual fluxes to sediments of phosphorus, nitrogen, carbon, and inorganic sediments have increased with time. A declining N–P ratio has increasingly favored nitrogen-fixing cyanobacteria. Increased deposition of microbial pigments and diatom frustules and a recent shift in diatom species also indicate increasing eutrophication. Biogenic silica increased with time, but there is no evidence of a near-surface decline that would indicate silica limitation. Stable isotopes suggest that an increasing proportion of carbon deposited in sediments is of in-lake origin, indicating increased productivity. In the basin nearest the town of Lac La Biche, an increase in δ15N followed the construction of the sewage treatment plant, but more recen...

Historical declines in chimney swift populations are associated with dramatic changes in insect prey consumption

ABSTRACT Background/Question/Methods Aerially-foraging insectivorous birds have experienced drama... more ABSTRACT Background/Question/Methods Aerially-foraging insectivorous birds have experienced dramatic population declines in North America over the past several decades, but a dearth of data on their limiting factors makes hypotheses about these declines difficult to test. The common link among these declining species is their diet and it is therefore likely that avian population changes are linked to changes in insect prey. If food has been a limiting factor, an assessment of historical dietary data should show a corresponding change in diet composition and insectivore abundance, however, historical data on most insect taxa are sparse or non-existent. We obtained an unprecedented opportunity to examine such data by assessing historical diet quality through the analysis of a preserved fecal deposit from a major historical chimney swift (Chaetura pelagica) roost at Queen&#39;s University in Kingston, Ontario, Canada. This stratified fecal deposit captures the record of ingested insects from 1928-1998. We removed samples from the deposit in 1 cm increments, and stable carbon (d13C) and nitrogen (d15N) isotopes were analyzed from subsamples. We also collected and identified insect fragments from these subsamples. Results/Conclusions Chimney swift populations began a sharp decline in 1965, concurrent with a dramatic reduction in d15N indicating a major change in prey composition was occurring. d15N levels returned to pre-1965 levels between approximately 1977 and 1988, while chimney swifts continued a sharp population decline that has yet to abate. The reduction in d15N levels in the 1960&#39;s represents a 50% drop in the trophic status of swifts, a change that could easily affect individual survival and brood-rearing. Our analysis of insect fragments in the fecal archive revealed a strong negative correlation between d15N levels and the per capita amount of remains of Dipterans (flies). Conversely, the per capita amount of remains from Coleopterans (beetles) and Hemipterans (true bugs) was positively associated with d15N levels. Therefore, we determined that the onset of the population crash for chimney swifts was associated with 1) a major reduction in the amount of beetle and bug prey, and 2) an increased reliance on fly prey. The causes for these changes in prey base remain to be seen, but may be related to historical use of pesticides and contaminants. If chimney swifts serve as a model species for all aerially-foraging insectivores, then our study may have revealed the historical proximate mechanism for their guild-wide decline.

COS 26-5: Historical declines in chimney swift populations are associated with dramatic changes in insect prey consumption

Arctic Seabirds Transport Marine-Derived Contaminants

Science, 2005

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arc... more Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems.

The Life Course “Connection”: An Exploration of Women’s Dietary Choices in a Northern First Nations Community

The high incidence of obesity and obesity related diseases have been welldocumented within First ... more The high incidence of obesity and obesity related diseases have been welldocumented within First Nations communities across Canada. Therefore, examining current dietary choices and then altering and managing alternative healthier choices are essential in the treatment of obesity and its related diseases. The present article describes a dietary study looking specifically

Supercritical carbon dioxide extraction of porogens for the preparation of ultralow-dielectric-constant films

Applied Physics Letters, 2003

Supercritical carbon dioxide (SCCO2) extraction of a CO 2-soluble poly(propylene glycol) (PPG) po... more Supercritical carbon dioxide (SCCO2) extraction of a CO 2-soluble poly(propylene glycol) (PPG) porogen from poly(methylsilsesquioxane) (PMSSQ) cured to temperatures adequate to initiate matrix condensation, but still below the decomposition temperature of the porogen is demonstrated to produce nanoporous, ultralow dielectric constant thin films. Both closed and open cell porous structures were prepared simply by varying the porogen load in the organic/inorganic hybrid films. The porogen loads investigated in the present work ranged from 25-55 wt.%. Structural characterization of the samples conducted using transmission electron microscope (TEM), small angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) confirms the successful extraction of the porogen from the PMSSQ matrix at relatively low temperatures (≤200 o C). The standard thermal decomposition process is performed at much higher temperatures (typically in the range of 400 o C-450 o C). The values of dielectric constants and refractive indices measured are in good agreement with the structural properties of these samples.

Dataset for: Simulating a spill of diluted bitumen: Environmental weathering and submergence in a model freshwater system

The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a... more The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a semi-liquid form of heavy crude oil mixed with natural gas condensates to facilitate transport. The weathering, fate, behaviour, and environmental effects of dilbit are crucial to consider when responding to a spill, however few environmental studies on dilbit have been completed. Here we report on 11-day long experimental spills of dilbit (Cold Lake Winter Blend) in outdoor micro-cosms meant to simulate a low-energy aquatic system containing natural lake water and sedi-ments treated with a low (1:8,000 oil:water) and high (1:800 oil:water) volume of dilbit. In the first 24 hours of the experiment, volatile hydrocarbons quickly evaporated from the dilbit, result-ing in increased dilbit density and viscosity. These changes in dilbit's physical and chemical properties ultimately led to its submergence after 8 days. We also detected rapid accumulation of polycyclic aromatic compounds i...

Tracking the Impacts of Recent Warming and Thaw of Permafrost Peatlands on Aquatic Ecosystems: A Multi-Proxy Approach Using Remote Sensing and Lake Sediments

J., thienpont J.r., Kimpe l.e., Blais J.m., Pisaric m.F.J. & smol J.P. 2015: tracking the impacts... more J., thienpont J.r., Kimpe l.e., Blais J.m., Pisaric m.F.J. & smol J.P. 2015: tracking the impacts of recent warming and thaw of permafrost peatlands on aquatic ecosystems: a multi-proxy approach using remote sensing and lake sediments. Boreal Env. Res. 20: 363-377. Regions within the discontinuous permafrost zone of the southern Northwest Territories (Canada) are experiencing accelerated thaw of permafrost as a result of recent warming. We used remotely-sensed imagery (1947-2012) to track changes in the extent of peat plateau collapse around two study lakes: KAK-1 and TAH-7. Subfossil diatoms were analyzed from sediment cores to reconstruct limnological changes over the past ~300 years and assess whether peatland subsidence affected lake ecology. Extensive peat plateau collapse was evident in catchments between 1970 and present day. In TAH-7, diatom assemblages indicated a substantial increase in coloured dissolved organic carbon coincident with the time of peat collapse, suggesting...

Jamaican bat guano_sterols and isotopes

Stable isotopes and sterols/stanols in bat guano from Belize and Jamaica

Extended study site descriptions and methods; dating profiles from Sterols and stanols as novel tracers of waterbird population dynamics in freshwater ponds

Sterol and stanol methods, sediment core dating, total Pb profiles, and personal correspondence

Data for: A bat guano deposit in Jamaica recorded agricultural changes and metal exposure over the last > 4,300 years

Radiometric dating; metals; stable isotopes; Pb-210; C-14; Organic C; Organic N; Sulphur

24.1.4 Social and Economic Conditions

Ecosystems and Human Well-being: Current State and Trends BOXES 24.1 Defining Mountains by Topogr... more Ecosystems and Human Well-being: Current State and Trends BOXES 24.1 Defining Mountains by Topography Only 24.2 Overutilization of Water from Mountain Areas Leading to Desertification 24.3 Floods, Landslides, and Reservoirs 24.4 An Institutional Definition of Property Rights 24.5 683 Mountain Systems Main Messages Half of the human population depends on mountains. Defined by elevation above sea level (minimum between 300 and 1000 meters, depending on latitude), steepness of slope (at least 2Њ over 25 kilometers, on the 30 arc-second grid), and excluding large plateaus, mountains occupy about one fifth of the terrestrial surface. Twenty percent (1.2 billion) of the world's human population lives in mountains or at their edges, and half of humankind depends in one way or the other on mountain resources (largely water). Mountains are characterized by high biodiversity. Because of the compression of climatic life zones with altitude and small-scale habitat diversity caused by different topoclimates, mountain regions are commonly more diverse than lowlands and are thus of prime conservation value. They support about one quarter of terrestrial biodiversity, with nearly half of the world's biodiversity hot spots concentrated in mountains. Geographically fragmented mountains support a high ethnocultural diversity. For many societies, mountains have spiritual significance, and scenic landscapes and clean air make mountains target regions for recreation and tourism. Thirty-two percent of protected areas are in mountains (9,345 mountain protected areas covering about 1.7 million square kilometers). Mountain ecosystems are exceptionally fragile. Mountains are subject to both natural and anthropogenic drivers of change. These range from volcanic and seismic events and flooding to global climate change and the loss of vegetation and soils because of inappropriate agricultural and forestry practices and extractive industries. Mountain biota are adapted to relatively narrow ranges of temperature (and hence altitude) and precipitation. Because of the sloping terrain and the relatively thin soils, the recovery of mountain ecosystems from disturbances is typically slow or does not occur. Human well-being depends on mountain resources. These ecosystems are particularly important for the provision of clean water, and their ecological integrity is key to the safety of settlements and transport routes. They harbor rich biodiversity and contribute substantially to global plant and animal production. All these services depend on slope stability and erosion control provided by a healthy vegetative cover. As ''water towers,'' mountains supply water to nearly half the human population, including some regions far from mountains, and mountain agriculture provides subsistence for about half a billion people. Key mountain resources and services include water for hydroelectricity, flood control, mineral resources, timber, and medicinal plants. Mountain populations have evolved a high diversity of cultures, including languages, and traditional agricultural knowledge commonly promotes sustainable production systems. In many mountain areas, tourism is a special form of highland-lowland interaction and forms the backbone of regional as well as national economies. In general, both poverty and ethnic diversity are higher in mountain regions, and people are often more vulnerable than people elsewhere. Ninety percent of the global mountain population of about 1.2 billion people lives in developing countries and countries in transition-with one third of these in China and half in the Asia-Pacific region. Some 90 million mountain people-and almost everyone living above 2500 meters-live in poverty and are considered especially vulnerable to food insecurity. Land use pressure puts mountain ecosystem integrity at risk in many parts of the world. Industrial use, forest destruction, overgrazing, and inappropriate cropping practices lead to irreversible losses of soil and ecosystem function, with increased environmental risks in both mountains and adjacent lowland areas. Mountains often represent political borders, restrict transport to narrow corridors, and are refuges for minorities and political opposition. As such they are often focal areas of armed conflicts. Further conflicts arise from the commercial exploitation of natural resources, usually by outside interests, and from ambiguity regarding traditional land use rights. Profits from extractive industries in mountains are not systematically reinvested either in the management of upland resources or the provision of benefits to mountain communities. Both poverty and remoteness are responsible for poor medical care and education systems in many mountain regions. Strengthened highland-lowland linkages improve sustainability for both upstream and downstream populations. Lowland-highland relationships, whether formal or informal, have the potential to pay for investments in protection and sustainable use of mountain resources. When full costs are taken into account, stewardship of upland resources generally yields greater and more sustainable economic returns both to the people living in the mountain areas and to the immediate downstream economies when compared with extractive activities. In many cases, the focal point of such interactions has been based on providing a sustainable and clean supply of water, the most important and increasingly limiting mountain resource. In steep terrain, more than anywhere else, catchment quality is intimately linked to ecosystem integrity and functioning. Thus environmental conservation and sustainable land use in the world's mountains are not only a necessary condition for sustainable local livelihoods, they are also key to human well-being for nearly half the world's population who live downstream and depend on mountain resources.

Published Heritage

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Mercury Partitioning in Surface Sediments of the Upper St. Lawrence River (Canada): Evidence of the Importance of the Sulphur Chemistry

An intensive survey of mercury speciation was performed at a site on the Upper St. Lawrence River... more An intensive survey of mercury speciation was performed at a site on the Upper St. Lawrence River near Cornwall, Ontario, Canada with a history mercury contamination in sediments. Surface sediments were collected every 1.50 h. Total mercury (Hgtotal), methyl-mercury (MeHg), organic carbon, inorganic and organic sulphur were determined in the solid fraction. Dissolved Hgtotal, MeHg and dissolved organic carbon (DOC) were measured in pore waters. Concentrations of Hgtotal in the upper layers (first 5 cm) were high, ranging from 1.42 to 25.8 nmol g−1 in solids and from 125 to 449 pM in pore waters. MeHg levels were also high, ranging from 4.34 to 34.1 pmol g−1 in solids and from 40 to 96 pM in pore waters. This amounts to up to 1.4 % of Hgtotal present as MeHg in solids and 64%

Microbial DNA records historical delivery of anthropogenic mercury

The ISME Journal, 2015

Mercury (Hg) is an anthropogenic pollutant that is toxic to wildlife and humans, but the response... more Mercury (Hg) is an anthropogenic pollutant that is toxic to wildlife and humans, but the response of remote ecosystems to globally distributed Hg is elusive. Here, we use DNA extracted from a dated sediment core to infer the response of microbes to historical Hg delivery. We observe a significant association between the mercuric reductase gene (merA) phylogeny and the timing of Hg deposition. Using relaxed molecular clock models, we show a significant increase in the scaled effective population size of the merA gene beginning~200 years ago, coinciding with the Industrial Revolution and a coincident strong signal for positive selection acting on residues in the terminal region of the mercuric reductase. This rapid evolutionary response of microbes to changes in the delivery of anthropogenic Hg indicates that microbial genomes record ecosystem response to pollutant deposition in remote regions.

Relations between lake morphometry and the presence of laminated lake sediments

Quaternary Science Reviews, 1998

In this paper we conduct an empirical test of a published equation which relates lake surface are... more In this paper we conduct an empirical test of a published equation which relates lake surface area and maximum lake depth to the presence or absence of laminated lake sediments. A 297 lake dataset from New York State and six regions in Canada, representing a number of biogeoclimatic zones, is employed. The results suggest that deeper lakes are more likely to contain laminated lake sediments than are shallower lakes. The percentage of lakes incorrectly predicted to contain laminated sediments (false positives) and that incorrectly predicted to contain massive sediments (false negatives), was much higher than that found in the study in which the original equation was developed. Its low predictive ability suggests, therefore, that in addition to lake morphometry, many other factors affect the formation and preservation of laminated sediments.

Seabird-driven shifts in Arctic pond ecosystems

Proceedings of the Royal Society B: Biological Sciences, 2009

Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients... more Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients across ecosystem boundaries, greatly enriching recipient food webs. As many of these animals biomagnify contaminants, they can also focus pollutants at toxic levels. Seabirds arguably represent the most significant biovectors of nutrients and contaminants from the ocean to the land, given their sheer numbers and global distribution. However, long-term census data on seabirds are rare. Using palaeolimnological proxies, we show that a colony of Arctic seabirds has experienced climate-induced population increases in recent decades. We then document increasing concentrations of contaminants, including polychlorinated biphenyls and cadmium, in pond sediments that are linked to biotransport by seabirds. Our findings suggest that climate-related shifts in global seabird populations will have the unexpected consequence of restructuring coastal ecosystems.

A test of the possible influence of seabird activity on the 210Pb flux in high Arctic ponds at Cape Vera, Devon Island, Nunavut: implications for radiochronology

Journal of Paleolimnology, 2008

... The seabird colony at Cape Vera is clearly transport-ing large quantities of marine-derived n... more

Impacts of seabird-derived nutrients on water quality and diatom assemblages from Cape Vera, Devon Island, Canadian High Arctic

Hydrobiologia, 2008

Allochthonous nutrient subsidies play an important role in shaping biotic communities, particular... more Allochthonous nutrient subsidies play an important role in shaping biotic communities, particularly in naturally oligotrophic ecosystems such as those commonly found in the Canadian High Arctic. Seabirds have been identified as an important vector capable of transporting significant quantities of nutrients from marine to terrestrial environments. However, the influence of seabird-derived nutrients on water quality and ecosystem functioning of Arctic freshwater systems has been largely unexplored. Here, we sampled 24 ponds on Cape Vera, Devon Island (Nunavut, Arctic Canada), an area that is home to over 10,000 nesting pairs of northern fulmars (Fulmarus glacialis), in order to explore the influence of seabirds on water quality and diatom ecology. Our data reveal distinctive water chemistry changes (e.g., high pH, nutrients) and diatom assemblages (e.g., very low diversity) related to varying degrees of bird influence. Using d 15 N as a proxy of trophic level, we show that a small but significant portion of the variance in the diatom species data can be explained by seabird-derived nutrients. Although the generation of robust quantitative models predicting d 15 N from fossil diatom data was limited by the overwhelming dominance of a few taxa, this study provides evidence that seabird-derived nutrients play a critical role in influencing the water quality of Arctic ponds. Interestingly, diatom assemblage composition does not respond in a simple fashion to seabird-derived nutrients, in contrast to diatom-nutrient relationships recorded in many temperate regions.

High Arctic Ponds Receiving Biotransported Nutrients from a Nearby Seabird Colony Are Also Subject to Potentially Toxic Loadings of Arsenic, Cadmium, and Zinc

Environmental Toxicology and Chemistry, 2009

The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients... more The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients and trace elements to a series of 10 ponds located along a gradient of seabird influence below a fulmar colony in the high Arctic (Cape Vera, Devon Island, Canada). Phosphorus, Cd, K, Zn, and As were identified as seabird-derived elements, having both a high concentration in fulmar guano and a low concentration in background pond sediments (i.e., a high biogenic enrichment factor). Fluxes of these elements were highest in the pond closest to the colony and declined exponentially with distance. Sediments in several of the ponds exceeded Canadian Sediment Quality Guidelines for the Protection of Aquatic Life set for As (5.9 mg/kg) and Cd (0.6 mg/kg), and in the pond closest to the colony, which receives the most seabird subsidies, sediments contained 343 mg/kg Zn, exceeding the threshold for probable adverse biological effects. Although nutrient subsidies from fulmars create an Arctic oasis at Cape Vera, which supports a variety of flora and fauna, the same biological transport pathway puts at risk some of these species by creating sedimentary As, Cd, and Zn concentrations at this remote site similar to those usually observed only near industrialized locations.

The cultural eutrophication of Lac la Biche, Alberta, Canada: a paleoecological study

Canadian Journal of Fisheries and Aquatic Sciences, 2008

A multiproxy paleoecological investigation of Lac la Biche, a large boreal lake in northeastern A... more A multiproxy paleoecological investigation of Lac la Biche, a large boreal lake in northeastern Alberta, Canada, revealed that the lake was eutrophic before European settlement but has undergone additional cultural eutrophication in the past 30 to 50 years. Annual fluxes to sediments of phosphorus, nitrogen, carbon, and inorganic sediments have increased with time. A declining N–P ratio has increasingly favored nitrogen-fixing cyanobacteria. Increased deposition of microbial pigments and diatom frustules and a recent shift in diatom species also indicate increasing eutrophication. Biogenic silica increased with time, but there is no evidence of a near-surface decline that would indicate silica limitation. Stable isotopes suggest that an increasing proportion of carbon deposited in sediments is of in-lake origin, indicating increased productivity. In the basin nearest the town of Lac La Biche, an increase in δ15N followed the construction of the sewage treatment plant, but more recen...

Historical declines in chimney swift populations are associated with dramatic changes in insect prey consumption

ABSTRACT Background/Question/Methods Aerially-foraging insectivorous birds have experienced drama... more ABSTRACT Background/Question/Methods Aerially-foraging insectivorous birds have experienced dramatic population declines in North America over the past several decades, but a dearth of data on their limiting factors makes hypotheses about these declines difficult to test. The common link among these declining species is their diet and it is therefore likely that avian population changes are linked to changes in insect prey. If food has been a limiting factor, an assessment of historical dietary data should show a corresponding change in diet composition and insectivore abundance, however, historical data on most insect taxa are sparse or non-existent. We obtained an unprecedented opportunity to examine such data by assessing historical diet quality through the analysis of a preserved fecal deposit from a major historical chimney swift (Chaetura pelagica) roost at Queen&#39;s University in Kingston, Ontario, Canada. This stratified fecal deposit captures the record of ingested insects from 1928-1998. We removed samples from the deposit in 1 cm increments, and stable carbon (d13C) and nitrogen (d15N) isotopes were analyzed from subsamples. We also collected and identified insect fragments from these subsamples. Results/Conclusions Chimney swift populations began a sharp decline in 1965, concurrent with a dramatic reduction in d15N indicating a major change in prey composition was occurring. d15N levels returned to pre-1965 levels between approximately 1977 and 1988, while chimney swifts continued a sharp population decline that has yet to abate. The reduction in d15N levels in the 1960&#39;s represents a 50% drop in the trophic status of swifts, a change that could easily affect individual survival and brood-rearing. Our analysis of insect fragments in the fecal archive revealed a strong negative correlation between d15N levels and the per capita amount of remains of Dipterans (flies). Conversely, the per capita amount of remains from Coleopterans (beetles) and Hemipterans (true bugs) was positively associated with d15N levels. Therefore, we determined that the onset of the population crash for chimney swifts was associated with 1) a major reduction in the amount of beetle and bug prey, and 2) an increased reliance on fly prey. The causes for these changes in prey base remain to be seen, but may be related to historical use of pesticides and contaminants. If chimney swifts serve as a model species for all aerially-foraging insectivores, then our study may have revealed the historical proximate mechanism for their guild-wide decline.

COS 26-5: Historical declines in chimney swift populations are associated with dramatic changes in insect prey consumption

Arctic Seabirds Transport Marine-Derived Contaminants

Science, 2005

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arc... more Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems.

The Life Course “Connection”: An Exploration of Women’s Dietary Choices in a Northern First Nations Community

The high incidence of obesity and obesity related diseases have been welldocumented within First ... more The high incidence of obesity and obesity related diseases have been welldocumented within First Nations communities across Canada. Therefore, examining current dietary choices and then altering and managing alternative healthier choices are essential in the treatment of obesity and its related diseases. The present article describes a dietary study looking specifically

Supercritical carbon dioxide extraction of porogens for the preparation of ultralow-dielectric-constant films

Applied Physics Letters, 2003

Supercritical carbon dioxide (SCCO2) extraction of a CO 2-soluble poly(propylene glycol) (PPG) po... more Supercritical carbon dioxide (SCCO2) extraction of a CO 2-soluble poly(propylene glycol) (PPG) porogen from poly(methylsilsesquioxane) (PMSSQ) cured to temperatures adequate to initiate matrix condensation, but still below the decomposition temperature of the porogen is demonstrated to produce nanoporous, ultralow dielectric constant thin films. Both closed and open cell porous structures were prepared simply by varying the porogen load in the organic/inorganic hybrid films. The porogen loads investigated in the present work ranged from 25-55 wt.%. Structural characterization of the samples conducted using transmission electron microscope (TEM), small angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) confirms the successful extraction of the porogen from the PMSSQ matrix at relatively low temperatures (≤200 o C). The standard thermal decomposition process is performed at much higher temperatures (typically in the range of 400 o C-450 o C). The values of dielectric constants and refractive indices measured are in good agreement with the structural properties of these samples.

Dataset for: Simulating a spill of diluted bitumen: Environmental weathering and submergence in a model freshwater system

The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a... more The main petroleum product transported through pipelines in Canada is diluted bitumen (dilbit), a semi-liquid form of heavy crude oil mixed with natural gas condensates to facilitate transport. The weathering, fate, behaviour, and environmental effects of dilbit are crucial to consider when responding to a spill, however few environmental studies on dilbit have been completed. Here we report on 11-day long experimental spills of dilbit (Cold Lake Winter Blend) in outdoor micro-cosms meant to simulate a low-energy aquatic system containing natural lake water and sedi-ments treated with a low (1:8,000 oil:water) and high (1:800 oil:water) volume of dilbit. In the first 24 hours of the experiment, volatile hydrocarbons quickly evaporated from the dilbit, result-ing in increased dilbit density and viscosity. These changes in dilbit's physical and chemical properties ultimately led to its submergence after 8 days. We also detected rapid accumulation of polycyclic aromatic compounds i...

Tracking the Impacts of Recent Warming and Thaw of Permafrost Peatlands on Aquatic Ecosystems: A Multi-Proxy Approach Using Remote Sensing and Lake Sediments

J., thienpont J.r., Kimpe l.e., Blais J.m., Pisaric m.F.J. & smol J.P. 2015: tracking the impacts... more J., thienpont J.r., Kimpe l.e., Blais J.m., Pisaric m.F.J. & smol J.P. 2015: tracking the impacts of recent warming and thaw of permafrost peatlands on aquatic ecosystems: a multi-proxy approach using remote sensing and lake sediments. Boreal Env. Res. 20: 363-377. Regions within the discontinuous permafrost zone of the southern Northwest Territories (Canada) are experiencing accelerated thaw of permafrost as a result of recent warming. We used remotely-sensed imagery (1947-2012) to track changes in the extent of peat plateau collapse around two study lakes: KAK-1 and TAH-7. Subfossil diatoms were analyzed from sediment cores to reconstruct limnological changes over the past ~300 years and assess whether peatland subsidence affected lake ecology. Extensive peat plateau collapse was evident in catchments between 1970 and present day. In TAH-7, diatom assemblages indicated a substantial increase in coloured dissolved organic carbon coincident with the time of peat collapse, suggesting...

Jamaican bat guano_sterols and isotopes

Stable isotopes and sterols/stanols in bat guano from Belize and Jamaica

Extended study site descriptions and methods; dating profiles from Sterols and stanols as novel tracers of waterbird population dynamics in freshwater ponds

Sterol and stanol methods, sediment core dating, total Pb profiles, and personal correspondence

Data for: A bat guano deposit in Jamaica recorded agricultural changes and metal exposure over the last > 4,300 years

Radiometric dating; metals; stable isotopes; Pb-210; C-14; Organic C; Organic N; Sulphur

24.1.4 Social and Economic Conditions

Ecosystems and Human Well-being: Current State and Trends BOXES 24.1 Defining Mountains by Topogr... more Ecosystems and Human Well-being: Current State and Trends BOXES 24.1 Defining Mountains by Topography Only 24.2 Overutilization of Water from Mountain Areas Leading to Desertification 24.3 Floods, Landslides, and Reservoirs 24.4 An Institutional Definition of Property Rights 24.5 683 Mountain Systems Main Messages Half of the human population depends on mountains. Defined by elevation above sea level (minimum between 300 and 1000 meters, depending on latitude), steepness of slope (at least 2Њ over 25 kilometers, on the 30 arc-second grid), and excluding large plateaus, mountains occupy about one fifth of the terrestrial surface. Twenty percent (1.2 billion) of the world's human population lives in mountains or at their edges, and half of humankind depends in one way or the other on mountain resources (largely water). Mountains are characterized by high biodiversity. Because of the compression of climatic life zones with altitude and small-scale habitat diversity caused by different topoclimates, mountain regions are commonly more diverse than lowlands and are thus of prime conservation value. They support about one quarter of terrestrial biodiversity, with nearly half of the world's biodiversity hot spots concentrated in mountains. Geographically fragmented mountains support a high ethnocultural diversity. For many societies, mountains have spiritual significance, and scenic landscapes and clean air make mountains target regions for recreation and tourism. Thirty-two percent of protected areas are in mountains (9,345 mountain protected areas covering about 1.7 million square kilometers). Mountain ecosystems are exceptionally fragile. Mountains are subject to both natural and anthropogenic drivers of change. These range from volcanic and seismic events and flooding to global climate change and the loss of vegetation and soils because of inappropriate agricultural and forestry practices and extractive industries. Mountain biota are adapted to relatively narrow ranges of temperature (and hence altitude) and precipitation. Because of the sloping terrain and the relatively thin soils, the recovery of mountain ecosystems from disturbances is typically slow or does not occur. Human well-being depends on mountain resources. These ecosystems are particularly important for the provision of clean water, and their ecological integrity is key to the safety of settlements and transport routes. They harbor rich biodiversity and contribute substantially to global plant and animal production. All these services depend on slope stability and erosion control provided by a healthy vegetative cover. As ''water towers,'' mountains supply water to nearly half the human population, including some regions far from mountains, and mountain agriculture provides subsistence for about half a billion people. Key mountain resources and services include water for hydroelectricity, flood control, mineral resources, timber, and medicinal plants. Mountain populations have evolved a high diversity of cultures, including languages, and traditional agricultural knowledge commonly promotes sustainable production systems. In many mountain areas, tourism is a special form of highland-lowland interaction and forms the backbone of regional as well as national economies. In general, both poverty and ethnic diversity are higher in mountain regions, and people are often more vulnerable than people elsewhere. Ninety percent of the global mountain population of about 1.2 billion people lives in developing countries and countries in transition-with one third of these in China and half in the Asia-Pacific region. Some 90 million mountain people-and almost everyone living above 2500 meters-live in poverty and are considered especially vulnerable to food insecurity. Land use pressure puts mountain ecosystem integrity at risk in many parts of the world. Industrial use, forest destruction, overgrazing, and inappropriate cropping practices lead to irreversible losses of soil and ecosystem function, with increased environmental risks in both mountains and adjacent lowland areas. Mountains often represent political borders, restrict transport to narrow corridors, and are refuges for minorities and political opposition. As such they are often focal areas of armed conflicts. Further conflicts arise from the commercial exploitation of natural resources, usually by outside interests, and from ambiguity regarding traditional land use rights. Profits from extractive industries in mountains are not systematically reinvested either in the management of upland resources or the provision of benefits to mountain communities. Both poverty and remoteness are responsible for poor medical care and education systems in many mountain regions. Strengthened highland-lowland linkages improve sustainability for both upstream and downstream populations. Lowland-highland relationships, whether formal or informal, have the potential to pay for investments in protection and sustainable use of mountain resources. When full costs are taken into account, stewardship of upland resources generally yields greater and more sustainable economic returns both to the people living in the mountain areas and to the immediate downstream economies when compared with extractive activities. In many cases, the focal point of such interactions has been based on providing a sustainable and clean supply of water, the most important and increasingly limiting mountain resource. In steep terrain, more than anywhere else, catchment quality is intimately linked to ecosystem integrity and functioning. Thus environmental conservation and sustainable land use in the world's mountains are not only a necessary condition for sustainable local livelihoods, they are also key to human well-being for nearly half the world's population who live downstream and depend on mountain resources.

Published Heritage

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Mercury Partitioning in Surface Sediments of the Upper St. Lawrence River (Canada): Evidence of the Importance of the Sulphur Chemistry

An intensive survey of mercury speciation was performed at a site on the Upper St. Lawrence River... more An intensive survey of mercury speciation was performed at a site on the Upper St. Lawrence River near Cornwall, Ontario, Canada with a history mercury contamination in sediments. Surface sediments were collected every 1.50 h. Total mercury (Hgtotal), methyl-mercury (MeHg), organic carbon, inorganic and organic sulphur were determined in the solid fraction. Dissolved Hgtotal, MeHg and dissolved organic carbon (DOC) were measured in pore waters. Concentrations of Hgtotal in the upper layers (first 5 cm) were high, ranging from 1.42 to 25.8 nmol g−1 in solids and from 125 to 449 pM in pore waters. MeHg levels were also high, ranging from 4.34 to 34.1 pmol g−1 in solids and from 40 to 96 pM in pore waters. This amounts to up to 1.4 % of Hgtotal present as MeHg in solids and 64%