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81 Research products, page 1 of 9

  • European Marine Science
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  • 2018-2022
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  • Open Access English
    Authors: 
    Dearnley, Jamie;
    Country: Canada

    Knowledge gaps pertaining to the remediation of freshwater lakes impacted by oil spills have persisted despite recent record highs for oil production and transportation across vulnerable regions in North America. The multiyear Freshwater Oil Spill Remediation Study (FOReSt), conducted at the IISD-Experimental Lakes Area in Canada, is focusing on the efficacy of minimally invasive methods for remediating oil spills in freshwater boreal lakes. In this thesis, the impacts and remediation of diluted bitumen (dilbit) and conventional heavy crude oil (CHV) spills were investigated (year 1), as were a variety of different remediation methods for spills of dilbit on different shoreline substrates (year 2). Two common small-bodied fish, fathead minnows (Promephales promelas) and finescale dace (Chrosomus neogaeus), were used to assess exposure to petrogenic polycyclic aromatic compounds (PACs) in model enclosed shoreline ecosystems impacted by spills and remediated using minimally invasive techniques. Short-term exposure to PACs, the most toxicologically relevant compounds in oil, was assessed in fish using biliary metabolite concentrations. In year one, finescale dace and fathead minnows residing in oil treated enclosures each had biliary pyrene metabolite concentrations that were positively correlated with pyrene concentrations in the water of the enclosures. Three months after the initial spills, fish in the enclosure receiving dilbit were significantly more exposed to PACs than fish in reference enclosures that did not receive oil. In year two, both finescale dace and fathead minnows residing in oil-treated exposures, regardless of shoreline substrate, showed increased exposure to PACs compared to fish in reference enclosures and the pristine lake environment two and a half months after the spills. No significant differences in exposure were observed among the remediation treatments. Biliary PAC metabolite concentrations were positively predicted by parent PAC concentrations in periphyton. PACs in periphyton two and a half months after oil introduction were positively correlated with PACs in the enclosures one week after spills, suggesting fish also had increased exposure to periphyton-bound alkyl-PACs. This thesis validates the use of small-bodied fish in assessing PAC exposure following freshwater oil spills and demonstrates the difficulties in estimating exposure using environmental concentrations in natural systems.

  • Open Access English
    Authors: 
    Yoon, Gwangseok;
    Country: Canada

    The environment during early life history strongly impacts phenotypic development in all organisms, which further influences developmental trajectory and ecological fitness later in life. Depending on the developmental stage and magnitude of change in the environment, phenotypes may become irreversible and thus have a long-lasting effect later in life. This thesis was designed to better understand how changes in the environment may influence plasticity and variation of metabolic phenotypes of Lake Sturgeon (Acipenser fulvescens) within the first year of life. Broadly speaking, the thesis tested two hypotheses that 1) all measured phenotypes would be plastic; and 2) durations of environmental effects on phenotypic development would be correlated with distinct developmental windows. Studies were developed to examine 1) short-term effects of temperature or diet on metabolic phenotypes such as metabolic rate, energy density, fatty acid profiles, and growth (Chapters 2 and 3) and 2) longer-term effects of temperature or diet during early life on these metabolic phenotypes (Chapters 4, 5 and 6). The first experimental chapter (Chapter 2) examined ontogenetic development of metabolic rate and demonstrated that dietary shifts between Artemia to bloodworm resulted in cessation of growth with elevated routine metabolic rate. Chapter 3 examined how fatty acid profiles and plasma cortisol concentration were influenced by environmental temperature and showed that decreasing temperature led to increases in mono- and polyunsaturated fatty acids in both phospholipids and triglycerides, and food deprivation resulted in lack of difference between baseline and peak cortisol concentrations. Chapter 4 examined how temperature during early life influenced plasticity of growth and showed that temperature post-dietary transition resulted in a transient effect on growth and energy metabolism without long-term effects post-winter. Chapter 5 examined how temperature during early life could influence growth and fatty acid metabolism when fish were exposed to colder temperatures later in life and demonstrated that elevated temperatures resulted in a longer-term effect on growth but lack of transcriptional responses of desaturating fatty acids when exposed to a cold temperature (3.5°C) later in life. The final experimental chapter, Chapter 6 examined longer-term effects of diet at the onset of exogenous feeding on metabolism and growth and demonstrated that an enriched diet resulted in prolonged effects on growth, digestive enzyme activity and survival prior to a simulated overwintering. This doctoral thesis research revealed that all measured metabolic phenotypes were plastic, but subtle changes in temperature and diet during early life history resulted in transient or prolonged effects on growth and metabolism in age-0 lake sturgeon. Results will aid our understanding of cohort and population dynamics as well as contribute to the development of conservation strategies for lake sturgeon, a species at risk or endangered across its natural range.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. Ocean samples for methane and nitrous oxide analysis were collected from Niskin bottles mounted on a CTD rosette. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). Equilibrium dry atmospheric concentrations were 328.25, 329.14, 330.11, and 330.96 ppb for N2O and 1919.64, 1933.67, 1934.92, and 1933.50 ppb for CH4 in 2015, 2016, 2017, and 2018, respectively. Equilibrium dissolved concentrations were calculated from the measured temperature and salinity following Wiesenburg and Guinasso (1979) for CH4 and Weiss and Price (1980) for N2O. Equilibrium concentrations were calculated based on sample temperature and salinity and the atmospheric N2O or CH4 concentrations measured at Barrow, Alaska by the NOAA Earth System Research Laboratory Global Monitoring Division (Dlugokencky et al., 2020a,b), with corrections to local sea level pressure and 100% humidity. Oxygen concentration was determined using an oxygen sensor mounted on the Niskin rosette, calibrated with discrete samples analyzed by Winkler titration. The mixed layer depth was defined based on a potential density difference criterion of 0.125 kg/m³ relative to the density at 5 m depth, using CTD profiles binned to 1 m. The mixed layer depth was set to 5 m as a minimum. The instantaneous gas transfer velocities and fluxes are based on the instantaneous wind speed at the time of sampling. The 30-day weighted gas transfer velocities and fluxes are integrated over the residence time of the gas in the mixed layer, using up to the prior 30 days of observations, following the method of Teeter et al. (2018) as described in the main manuscript of Manning et al. (2022). The 60-day weighted gas transfer velocities and fluxes are integrated over the residence time of the gas in the mixed layer, using the prior 60 days of observations, following the method of Teeter et al. (2018) as described in the main manuscript of Manning et al. (2022). Atmospheric sea level pressure was obtained from the NCEP/NCAR reanalysis product, which is provided by the NOAA-ESRL Physical Sciences Laboratory (https://psl.noaa.gov/data/gridded). Fractional ice cover was obtained from the EUMETSAT Ocean and Sea Ice Satellite Application Facility (https://osi-saf.eumetsat.int). Sea ice concentration product AMSR-2 (identifier OSI-408) was used in 2017–2018 and SSMIS (identifier OSI-401-b) was used in 2015–2016.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. Ocean samples for methane and nitrous oxide analysis were collected from Niskin bottles mounted on a CTD rosette. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). Equilibrium dry atmospheric concentrations were 328.25, 329.14, 330.11, and 330.96 ppb for N2O and 1919.64, 1933.67, 1934.92, and 1933.50 ppb for CH4 in 2015, 2016, 2017, and 2018, respectively. Equilibrium dissolved concentrations were calculated from the measured temperature and salinity following Wiesenburg and Guinasso (1979) for CH4 and Weiss and Price (1980) for N2O. Equilibrium concentrations were calculated based on sample temperature and salinity and the atmospheric N2O or CH4 concentrations measured at Barrow, Alaska by the NOAA Earth System Research Laboratory Global Monitoring Division (Dlugokencky et al., 2020a,b), with corrections to local sea level pressure and 100% humidity. Oxygen concentration was determined using an oxygen sensor mounted on the Niskin rosette, calibrated with discrete samples analyzed by Winkler titration. The mixed layer depth was defined based on a potential density difference criterion of 0.125 kg/m³ relative to the density at 5 m depth, using CTD profiles binned to 1 m. The mixed layer depth was set to 5 m as a minimum. For methane δ13C, samples were pre-concentrated through a purge and trap system (Finnigan PreCon Trace Gas Pre-Concentrator) and measured with a Finnigan Delta XP Plus mass spectrometer following the method of Damm et al. (2015).

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. It also contains methane and nitrous oxide dissolved gas concentration and dissolved methane carbon isotope data from rivers in the Canadian Arctic Archipelago region collected between 2017-2019.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration and dissolved methane carbon isotope data from rivers in the Canadian Arctic Archipelago region collected between 2017-2019. River samples were collected during CCGS Amundsen cruises using a helicopter to travel to the rivers. At each river site, river water was pumped through tubing using a peristaltic pump. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). For methane 𝛿13C, samples (one sample per event) were pre-concentrated through a purge and trap system (Finnigan PreCon Trace Gas Pre-Concentrator) and measured with a Finnigan Delta XP Plus mass spectrometer following the method of Damm et al. (2015).

  • Open Access English
    Authors: 
    Schembri, Sarah; Deschepper, Inge; Myers, Paul G.; Sirois, Pascal; Fortier, Louis; Bouchard, Caroline; Maps, Frederic;
    Country: Canada

    Buoyant Arctic cod (Boreogadus saida) eggs are found at the surface or at the ice-water interface in winter. While winter temperatures in saline waters fall below 0 degrees C, the temperature in areas affected by under-ice river plumes is slightly higher. Under-ice river plumes may therefore provide thermal refuges favoring the survival of the vulnerable early life stages of Arctic cod. Thermal refuges would allow early hatchers to survive, benefit from a long growing period, and add to the number of individuals recruiting to the adult population: These expectations define the freshwater winter refuge hypothesis. More than 42 rivers drain into Hudson Bay making it particularly well suited to test this hypothesis. Whereas the bulk of Arctic cod observed in Hudson Bay hatch between mid-April and June, some larvae hatch as early as January. We used two independent but complementary methods to test the hypothesis: (1) Lagrangian model simulations that traced back the planktonic trajectories of the sampled larvae and (2) measurements of the concentration of strontium-88 in the otolith cores. Throughout the Hudson Bay system, Lagrangian simulations revealed that early hatchers were more likely to hatch in lower surface salinities and that larvae reaching larger prewinter lengths were likely to have hatched near or within estuaries. Analysis of otolith microchemistry showed that larvae with low strontium-88 concentration in the otolith core, indicating a low salinity hatch location, had hatched earlier and thus had a longer growth period before freeze-up. These results show the potential for Arctic cod persistence in the Arctic where freshwater input is projected to increase and the ice regime is predicted to become more seasonal, provided that the surface temperatures remain below embryonic and larval lethal limits.

  • Other research product . Other ORP type . 2021
    Open Access English
    Authors: 
    Bailey, Neal;
    Country: Canada

    Mercury is a potent toxicant whose concentration in the environment has increased markedly due to human activity. However, uncertainties exist on sources and sinks of mercury, including those associated with mineral dust, with the Sahara Desert being the largest aeolian dust source worldwide. To characterize mercury associated with Saharan dust export to the Atlantic Ocean, aeolian dust (>2.2 µm in size) and soil samples were collected from the Canary Islands and Cabo Verde, ~400 and 800 km off the west coast of Africa. The sources of the dust samples were determined by back-trajectory analysis, and mercury content was characterized via direct mercury analysis. Mercury concentrations differed significantly (p 70%) over the Atlantic Ocean, had a mean mercury concentration of 29.8±31.3 ng/g (w/w), or 1.40±1.34 pg/m3 (w/v); this result is in the lower end of the data reported for remote coastal locations on a w/v basis, but lower than any on a w/w basis. Saharan-origin dust, defined as dust with a back trajectory predominantly (>70%) over the Sahara Desert, had a higher mean mercury concentration of 72.8±7.43 ng/g, or 4.64±2.15 pg/m3. Concentrations of mercury in dust samples were found to increase as back trajectories passed over a larger extent of the western African land surface relative to the Atlantic Ocean water surface. Finally, particulate-bound mercury (PBM) concentrations measured at Cabo Verde were used to estimate the flux of particulate mercury to major dust-impacted regions of the Atlantic Ocean, an area comprising 21.3 million km2. The PBM flux to this region is estimated at 6.5±2.2 t/y if all dust originates from the Sahara, or 3.6±1.6 t/y if the dust is of mixed Saharan and Atlantic origins. These numbers represent only ~1% to 3% of the total mercury deposition to the region estimated by current global mercury models. Surface soil mercury concentrations measured in the Canary Islands further support minimal mercury inputs from Saharan dust. Our study thus suggests the current models may have considerably overestimated Saharan dust contribution to mercury deposition.

  • Open Access English
    Authors: 
    Espinasse, Boris; St John Glew, Katie;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC , EC | ISOMOD (894296), EC | ISOZOO (302010)

    We produced carbon and nitrogen isoscapes across the entire Southern Ocean (>40°S) using surface particulate organic matter isotope data, collected over the past 50 years. We used Integrated Nested Laplace Approximation -based approaches to predict mean annual isoscapes and four seasonal isoscapes using a suite of environmental data as predictor variables.

  • Open Access English
    Authors: 
    Jackson, Brianna;
    Country: Canada

    The extraction of bitumen from Alberta’s oil sands region generates large volumes of oil sands process-affected water (OSPW) that are stored in tailings ponds. New policy directives are planning to intentionally release OSPW into surrounding freshwater ecosystems. Presently, no water quality standards exist for the main toxic constituent of OSPW - naphthenic acid fraction components (NAFCs). To aid in the establishment of safe-release thresholds of OSPW, we exposed embryo fathead minnow (Pimephales promelas) to OSPW-derived NAFCs (2.5-54 mg/L) from 1-day post-fertilization to hatch in semi-natural conditions. Observations on embryo heart rate, embryo development, and basal activity at hatch were examined, to assess the developmental and behavioural toxicity of NAFCs. Embryo heart rates declined with increasing exposure concentration. NAFCs caused embryo mortality (LC50=26.76 mg/L) and development impairments at hatch (EC50=14.38 mg/L). Non-viable fish displayed pericardial and yolk sac edemas, craniofacial defects, and spinal curvatures that increased in severity with increasing exposure concentration. Acute narcosis, cardiac dysfunction, oxidative stress, and alteration in gene expression were probable modes of toxic action. At concentrations above 21 mg/L, fish displayed erratic and repetitive twitching patterns indicative of nervous system impairment. Post-hatch mass increased with increasing exposure concentration, potentially as a short term, compensatory-like response. Additionally, a reduction in basal activity was observed for fish exposed to 2.5 and 6.5 mg/L. This result suggests there could be sublethal effects for fish exposed to NAFC concentrations much lower than those known to cause mortality and developmental impairments. Taken together, these results provide important toxicological information to inform future regulatory policies for the management of OSPW in Alberta, Canada.

Advanced search in Research products
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Searching FieldsTerms
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The following results are related to European Marine Science. Are you interested to view more results? Visit OpenAIRE - Explore.
81 Research products, page 1 of 9
  • Open Access English
    Authors: 
    Dearnley, Jamie;
    Country: Canada

    Knowledge gaps pertaining to the remediation of freshwater lakes impacted by oil spills have persisted despite recent record highs for oil production and transportation across vulnerable regions in North America. The multiyear Freshwater Oil Spill Remediation Study (FOReSt), conducted at the IISD-Experimental Lakes Area in Canada, is focusing on the efficacy of minimally invasive methods for remediating oil spills in freshwater boreal lakes. In this thesis, the impacts and remediation of diluted bitumen (dilbit) and conventional heavy crude oil (CHV) spills were investigated (year 1), as were a variety of different remediation methods for spills of dilbit on different shoreline substrates (year 2). Two common small-bodied fish, fathead minnows (Promephales promelas) and finescale dace (Chrosomus neogaeus), were used to assess exposure to petrogenic polycyclic aromatic compounds (PACs) in model enclosed shoreline ecosystems impacted by spills and remediated using minimally invasive techniques. Short-term exposure to PACs, the most toxicologically relevant compounds in oil, was assessed in fish using biliary metabolite concentrations. In year one, finescale dace and fathead minnows residing in oil treated enclosures each had biliary pyrene metabolite concentrations that were positively correlated with pyrene concentrations in the water of the enclosures. Three months after the initial spills, fish in the enclosure receiving dilbit were significantly more exposed to PACs than fish in reference enclosures that did not receive oil. In year two, both finescale dace and fathead minnows residing in oil-treated exposures, regardless of shoreline substrate, showed increased exposure to PACs compared to fish in reference enclosures and the pristine lake environment two and a half months after the spills. No significant differences in exposure were observed among the remediation treatments. Biliary PAC metabolite concentrations were positively predicted by parent PAC concentrations in periphyton. PACs in periphyton two and a half months after oil introduction were positively correlated with PACs in the enclosures one week after spills, suggesting fish also had increased exposure to periphyton-bound alkyl-PACs. This thesis validates the use of small-bodied fish in assessing PAC exposure following freshwater oil spills and demonstrates the difficulties in estimating exposure using environmental concentrations in natural systems.

  • Open Access English
    Authors: 
    Yoon, Gwangseok;
    Country: Canada

    The environment during early life history strongly impacts phenotypic development in all organisms, which further influences developmental trajectory and ecological fitness later in life. Depending on the developmental stage and magnitude of change in the environment, phenotypes may become irreversible and thus have a long-lasting effect later in life. This thesis was designed to better understand how changes in the environment may influence plasticity and variation of metabolic phenotypes of Lake Sturgeon (Acipenser fulvescens) within the first year of life. Broadly speaking, the thesis tested two hypotheses that 1) all measured phenotypes would be plastic; and 2) durations of environmental effects on phenotypic development would be correlated with distinct developmental windows. Studies were developed to examine 1) short-term effects of temperature or diet on metabolic phenotypes such as metabolic rate, energy density, fatty acid profiles, and growth (Chapters 2 and 3) and 2) longer-term effects of temperature or diet during early life on these metabolic phenotypes (Chapters 4, 5 and 6). The first experimental chapter (Chapter 2) examined ontogenetic development of metabolic rate and demonstrated that dietary shifts between Artemia to bloodworm resulted in cessation of growth with elevated routine metabolic rate. Chapter 3 examined how fatty acid profiles and plasma cortisol concentration were influenced by environmental temperature and showed that decreasing temperature led to increases in mono- and polyunsaturated fatty acids in both phospholipids and triglycerides, and food deprivation resulted in lack of difference between baseline and peak cortisol concentrations. Chapter 4 examined how temperature during early life influenced plasticity of growth and showed that temperature post-dietary transition resulted in a transient effect on growth and energy metabolism without long-term effects post-winter. Chapter 5 examined how temperature during early life could influence growth and fatty acid metabolism when fish were exposed to colder temperatures later in life and demonstrated that elevated temperatures resulted in a longer-term effect on growth but lack of transcriptional responses of desaturating fatty acids when exposed to a cold temperature (3.5°C) later in life. The final experimental chapter, Chapter 6 examined longer-term effects of diet at the onset of exogenous feeding on metabolism and growth and demonstrated that an enriched diet resulted in prolonged effects on growth, digestive enzyme activity and survival prior to a simulated overwintering. This doctoral thesis research revealed that all measured metabolic phenotypes were plastic, but subtle changes in temperature and diet during early life history resulted in transient or prolonged effects on growth and metabolism in age-0 lake sturgeon. Results will aid our understanding of cohort and population dynamics as well as contribute to the development of conservation strategies for lake sturgeon, a species at risk or endangered across its natural range.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. Ocean samples for methane and nitrous oxide analysis were collected from Niskin bottles mounted on a CTD rosette. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). Equilibrium dry atmospheric concentrations were 328.25, 329.14, 330.11, and 330.96 ppb for N2O and 1919.64, 1933.67, 1934.92, and 1933.50 ppb for CH4 in 2015, 2016, 2017, and 2018, respectively. Equilibrium dissolved concentrations were calculated from the measured temperature and salinity following Wiesenburg and Guinasso (1979) for CH4 and Weiss and Price (1980) for N2O. Equilibrium concentrations were calculated based on sample temperature and salinity and the atmospheric N2O or CH4 concentrations measured at Barrow, Alaska by the NOAA Earth System Research Laboratory Global Monitoring Division (Dlugokencky et al., 2020a,b), with corrections to local sea level pressure and 100% humidity. Oxygen concentration was determined using an oxygen sensor mounted on the Niskin rosette, calibrated with discrete samples analyzed by Winkler titration. The mixed layer depth was defined based on a potential density difference criterion of 0.125 kg/m³ relative to the density at 5 m depth, using CTD profiles binned to 1 m. The mixed layer depth was set to 5 m as a minimum. The instantaneous gas transfer velocities and fluxes are based on the instantaneous wind speed at the time of sampling. The 30-day weighted gas transfer velocities and fluxes are integrated over the residence time of the gas in the mixed layer, using up to the prior 30 days of observations, following the method of Teeter et al. (2018) as described in the main manuscript of Manning et al. (2022). The 60-day weighted gas transfer velocities and fluxes are integrated over the residence time of the gas in the mixed layer, using the prior 60 days of observations, following the method of Teeter et al. (2018) as described in the main manuscript of Manning et al. (2022). Atmospheric sea level pressure was obtained from the NCEP/NCAR reanalysis product, which is provided by the NOAA-ESRL Physical Sciences Laboratory (https://psl.noaa.gov/data/gridded). Fractional ice cover was obtained from the EUMETSAT Ocean and Sea Ice Satellite Application Facility (https://osi-saf.eumetsat.int). Sea ice concentration product AMSR-2 (identifier OSI-408) was used in 2017–2018 and SSMIS (identifier OSI-401-b) was used in 2015–2016.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. Ocean samples for methane and nitrous oxide analysis were collected from Niskin bottles mounted on a CTD rosette. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). Equilibrium dry atmospheric concentrations were 328.25, 329.14, 330.11, and 330.96 ppb for N2O and 1919.64, 1933.67, 1934.92, and 1933.50 ppb for CH4 in 2015, 2016, 2017, and 2018, respectively. Equilibrium dissolved concentrations were calculated from the measured temperature and salinity following Wiesenburg and Guinasso (1979) for CH4 and Weiss and Price (1980) for N2O. Equilibrium concentrations were calculated based on sample temperature and salinity and the atmospheric N2O or CH4 concentrations measured at Barrow, Alaska by the NOAA Earth System Research Laboratory Global Monitoring Division (Dlugokencky et al., 2020a,b), with corrections to local sea level pressure and 100% humidity. Oxygen concentration was determined using an oxygen sensor mounted on the Niskin rosette, calibrated with discrete samples analyzed by Winkler titration. The mixed layer depth was defined based on a potential density difference criterion of 0.125 kg/m³ relative to the density at 5 m depth, using CTD profiles binned to 1 m. The mixed layer depth was set to 5 m as a minimum. For methane δ13C, samples were pre-concentrated through a purge and trap system (Finnigan PreCon Trace Gas Pre-Concentrator) and measured with a Finnigan Delta XP Plus mass spectrometer following the method of Damm et al. (2015).

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration, dissolved methane carbon isotope, and ancillary hydrographic data from research cruises in the North American Arctic Ocean between 2015-2018. It also contains methane and nitrous oxide dissolved gas concentration and dissolved methane carbon isotope data from rivers in the Canadian Arctic Archipelago region collected between 2017-2019.

  • Open Access English
    Authors: 
    Manning, Cara C M; Zheng, Zhiyin; Fenwick, Lindsay; McCulloch, Ross D; Damm, Ellen; Izett, Robert W; Williams, William J; Zimmermann, Sarah; Vagle, Svein; Tortell, Philippe Daniel;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    This dataset contains methane and nitrous oxide dissolved gas concentration and dissolved methane carbon isotope data from rivers in the Canadian Arctic Archipelago region collected between 2017-2019. River samples were collected during CCGS Amundsen cruises using a helicopter to travel to the rivers. At each river site, river water was pumped through tubing using a peristaltic pump. Water was collected into glass serum bottles and allowed to overflow three times before preserving with mercuric chloride and sealing with butyl rubber stoppers and aluminum crimp seals. Gas concentrations were determined using a purge and trap system coupled to a gas chromatograph/mass spectrometer, following the method of Capelle et al. (2015). For methane 𝛿13C, samples (one sample per event) were pre-concentrated through a purge and trap system (Finnigan PreCon Trace Gas Pre-Concentrator) and measured with a Finnigan Delta XP Plus mass spectrometer following the method of Damm et al. (2015).

  • Open Access English
    Authors: 
    Schembri, Sarah; Deschepper, Inge; Myers, Paul G.; Sirois, Pascal; Fortier, Louis; Bouchard, Caroline; Maps, Frederic;
    Country: Canada

    Buoyant Arctic cod (Boreogadus saida) eggs are found at the surface or at the ice-water interface in winter. While winter temperatures in saline waters fall below 0 degrees C, the temperature in areas affected by under-ice river plumes is slightly higher. Under-ice river plumes may therefore provide thermal refuges favoring the survival of the vulnerable early life stages of Arctic cod. Thermal refuges would allow early hatchers to survive, benefit from a long growing period, and add to the number of individuals recruiting to the adult population: These expectations define the freshwater winter refuge hypothesis. More than 42 rivers drain into Hudson Bay making it particularly well suited to test this hypothesis. Whereas the bulk of Arctic cod observed in Hudson Bay hatch between mid-April and June, some larvae hatch as early as January. We used two independent but complementary methods to test the hypothesis: (1) Lagrangian model simulations that traced back the planktonic trajectories of the sampled larvae and (2) measurements of the concentration of strontium-88 in the otolith cores. Throughout the Hudson Bay system, Lagrangian simulations revealed that early hatchers were more likely to hatch in lower surface salinities and that larvae reaching larger prewinter lengths were likely to have hatched near or within estuaries. Analysis of otolith microchemistry showed that larvae with low strontium-88 concentration in the otolith core, indicating a low salinity hatch location, had hatched earlier and thus had a longer growth period before freeze-up. These results show the potential for Arctic cod persistence in the Arctic where freshwater input is projected to increase and the ice regime is predicted to become more seasonal, provided that the surface temperatures remain below embryonic and larval lethal limits.

  • Other research product . Other ORP type . 2021
    Open Access English
    Authors: 
    Bailey, Neal;
    Country: Canada

    Mercury is a potent toxicant whose concentration in the environment has increased markedly due to human activity. However, uncertainties exist on sources and sinks of mercury, including those associated with mineral dust, with the Sahara Desert being the largest aeolian dust source worldwide. To characterize mercury associated with Saharan dust export to the Atlantic Ocean, aeolian dust (>2.2 µm in size) and soil samples were collected from the Canary Islands and Cabo Verde, ~400 and 800 km off the west coast of Africa. The sources of the dust samples were determined by back-trajectory analysis, and mercury content was characterized via direct mercury analysis. Mercury concentrations differed significantly (p 70%) over the Atlantic Ocean, had a mean mercury concentration of 29.8±31.3 ng/g (w/w), or 1.40±1.34 pg/m3 (w/v); this result is in the lower end of the data reported for remote coastal locations on a w/v basis, but lower than any on a w/w basis. Saharan-origin dust, defined as dust with a back trajectory predominantly (>70%) over the Sahara Desert, had a higher mean mercury concentration of 72.8±7.43 ng/g, or 4.64±2.15 pg/m3. Concentrations of mercury in dust samples were found to increase as back trajectories passed over a larger extent of the western African land surface relative to the Atlantic Ocean water surface. Finally, particulate-bound mercury (PBM) concentrations measured at Cabo Verde were used to estimate the flux of particulate mercury to major dust-impacted regions of the Atlantic Ocean, an area comprising 21.3 million km2. The PBM flux to this region is estimated at 6.5±2.2 t/y if all dust originates from the Sahara, or 3.6±1.6 t/y if the dust is of mixed Saharan and Atlantic origins. These numbers represent only ~1% to 3% of the total mercury deposition to the region estimated by current global mercury models. Surface soil mercury concentrations measured in the Canary Islands further support minimal mercury inputs from Saharan dust. Our study thus suggests the current models may have considerably overestimated Saharan dust contribution to mercury deposition.

  • Open Access English
    Authors: 
    Espinasse, Boris; St John Glew, Katie;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC , EC | ISOMOD (894296), EC | ISOZOO (302010)

    We produced carbon and nitrogen isoscapes across the entire Southern Ocean (>40°S) using surface particulate organic matter isotope data, collected over the past 50 years. We used Integrated Nested Laplace Approximation -based approaches to predict mean annual isoscapes and four seasonal isoscapes using a suite of environmental data as predictor variables.

  • Open Access English
    Authors: 
    Jackson, Brianna;
    Country: Canada

    The extraction of bitumen from Alberta’s oil sands region generates large volumes of oil sands process-affected water (OSPW) that are stored in tailings ponds. New policy directives are planning to intentionally release OSPW into surrounding freshwater ecosystems. Presently, no water quality standards exist for the main toxic constituent of OSPW - naphthenic acid fraction components (NAFCs). To aid in the establishment of safe-release thresholds of OSPW, we exposed embryo fathead minnow (Pimephales promelas) to OSPW-derived NAFCs (2.5-54 mg/L) from 1-day post-fertilization to hatch in semi-natural conditions. Observations on embryo heart rate, embryo development, and basal activity at hatch were examined, to assess the developmental and behavioural toxicity of NAFCs. Embryo heart rates declined with increasing exposure concentration. NAFCs caused embryo mortality (LC50=26.76 mg/L) and development impairments at hatch (EC50=14.38 mg/L). Non-viable fish displayed pericardial and yolk sac edemas, craniofacial defects, and spinal curvatures that increased in severity with increasing exposure concentration. Acute narcosis, cardiac dysfunction, oxidative stress, and alteration in gene expression were probable modes of toxic action. At concentrations above 21 mg/L, fish displayed erratic and repetitive twitching patterns indicative of nervous system impairment. Post-hatch mass increased with increasing exposure concentration, potentially as a short term, compensatory-like response. Additionally, a reduction in basal activity was observed for fish exposed to 2.5 and 6.5 mg/L. This result suggests there could be sublethal effects for fish exposed to NAFC concentrations much lower than those known to cause mortality and developmental impairments. Taken together, these results provide important toxicological information to inform future regulatory policies for the management of OSPW in Alberta, Canada.