dept. of physical & environmental sciences · 12:00 - 12:15 tingting zhu zachary di loreto...

Dept. of Physical & Environmental Sciences

3rd Doctoral Environmental Science Colloquium May 4th - 5th 2017

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DESC III Student Organizing Committee

Shahrzad Davarpanah Jazi

Brian Pentz

Departmental Assistance

Prof. Roberta Fulthorpe

Elaine Pick

Winner of DESC III booklet cover art competition

Maryam Abdinejad

Location

University of Toronto Scarborough

AA112

Many thanks to Dr. Tony Walker for travelling to Toronto

to give DESC III’s keynote presentation.

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Day 1: Thursday May 4th 2017 – 9:00 am – 3:45 pm

TIME SPEAKERS CHAIRS FEEDBACK

9:00 - 9:30 BREAKFAST

9:30 - 9:45

Dr. Tony Walker

Brian Pentz

&

Shahrzad Davarpanah Jazi

N /A 9:45 - 10:00

10:00 - 10:15

10:15 - 10:30

10:30 - 10:45 David McLagan Maryam Abdinejad

&

Patricia Miller

Stephanie Gagliardi

10:45 - 11:00 Nicole Spiegelaar Bryan Flood

11:00 - 11:30 COFFEE BREAK

11:30 - 11:45 Stuart Livingstone Nasrine Mostafavipak

&

Paris Ning

Megan Sheremata

11:45 - 12:00 Shahrzad Davarpanah Jazi Yuchao Wan

12:00 - 12:15 Tingting Zhu Zachary Di Loreto

12:15 - 12:30 Brian Pentz Ye Tao

&

Katherine Balasingham

Ariola Visha

12:30 - 12:45 Maryam Tabatabaie

Anaraki

Nasrine

Mostafavipak

12:45 - 1:00 Ellen Gute Raul Salas Reyes

1:00 - 2:00 LUNCH BREAK (Location: HW 305)

2:00 - 2:15 Megan Sheremata Cindy Yang

&

Ellen Gute

Paris Ning

2:15 - 2:30 Bryan Flood Patricia Miller

2:30 - 2:45 Ammar Al-Ibrahim Boluwatife

Awonaike

2:45 - 3:00 Rhea Lumactud Linh Viet Nguyen

&

Emily Chenery

&

Yuchao Wan

Felicity Ni

3:00 - 3:15 Boluwatife Awonaike Qianwen Shi

3:15 - 3:30 Slowamir Kowal Ammar Al-Ibrahim

3:30 - 3:45 Tej Heer Ye Tao

3:45 - 4:00 ADJOURN

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Day 2: Friday May 5th 2017 – 9:45 am – 3:45 pm

TIME SPEAKERS CHAIRS FEEDBACK

9:45 - 10:15 BREAKFAST

10:15 - 10:30 Paris Ning Maryam Tabatabaie

Anaraki

&

Raul Salas Reyes

Tingting Zhu

10:30 - 10:45 JP Fontenelle Nicole Spiegelaar

10:45 - 11:00 Maryam Abdinejad Ana Zaknic-Catovic

11:00 - 11:30 COFFEE BREAK

11:30 - 11:45 Samarth Kaluskar

Stephanie Gagliardi

&

Boluwatife Awonaike

Christine Palermo

11:45 - 12:00 Yalda Liaghati Mobarhan Emily Chenery

12:00 - 12:15 Patricia Miller Aime Kayembe

12:15 - 12:30 Nasrine Mostafavipak

Andrew Apostoli

&

JP Fontenelle

Samarth Kaluskar

12:30 - 12:45 Yuchao Wan David Mclagan

12:45 - 1:00 Qianwen Shi Shane Sookhan

1:00 - 2:00 LUNCH BREAK (Location: HW 305)

2:00 - 2:15 Ana Zaknic-Catovic

Andrew Zajch

&

Qianwen Shi

Slowamir Kowal

2:15 - 2:30 Linh Viet Nguyen Shahrzad

Davarpanah Jazi

2:30 - 2:45 Shane Sookhan Maryam Tabatabaei

Anaraki

2:45 - 3:00 Ariola Visha

Ammar Al-Ibrahim

&

Zachary Di Loreto

&

Shane Sookhan

Yalda Liaghati

Mobarhan

3:00 – 3:15 Aime Kayembe Brian Pentz

3:15 – 3:30 Christine Palermo Linh Viet Nguyen

3:30 – 3:45 Felicity Ni Katherine

Balasingham

3:45 - 4:00 ADJOURN

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Keynote Presentation

Thu. May 4th 2017 9:30 am – Chairs: Brian Pentz & Shahrzad Davarpanah Jazi

Dr. Tony Walker

Assistant Professor

Dalhousie University

School for Resource and Environmental Studies

Halifax, Nova Scotia

Dr. Walker currently focuses his research efforts on management

and remediation of contaminated sites, ecological impacts and

mitigation of industrial pollution, ecological risk assessment and

environmental effects monitoring, management of aquaculture

impacts, management of Arctic and Antarctic natural resources,

air pollution impacts on ecosystems. Most of his recent research

has been in partnership with industry related to environmental

management and monitoring across Canada.

Environmental Science! So What?: Turning Empirical Environmental Science

Data into Effective Environmental Policies

This presentation by Dr. Walker provides examples of his broad research background that is very

complimentary to the types of environmental research conducted here at the University of

Toronto. Dr. Walker’s research has previously focused on the collection and interpretation of

empirical data related to oceans, energy and the environment for many years. Research related to

human interactions with Antarctic marine living resources, environmental pollution in the

Russian Arctic from resource exploitation, and marine environmental effects monitoring during

large scale environmental remediation projects in Canada are just some examples of previous

environmental research that will be discussed. Examples of Dr. Walker’s current research related

to environmental pollution monitoring and mitigation has begun to bridge the gaps that exist

between environmental science and both policy and environmental management. This

presentation will conclude with some ideas for future research that aims to improve the

environment by creating, applying and sharing knowledge. Future environmental science and

policy research should aim to solve a range of complex, interdisciplinary environmental problems

that should be addressed by strong teams from academia, government and industry.

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Session 1 – Thu. 10:30 am – Chairs: Maryam Abdinejad & Patricia Miller

Monitoring Gaseous Mercury with a Precise, Accurate and Inexpensive Passive

Sampler

David S. McLagan, Carl P. J. Mitchell, and Frank Wania

Our recently introduced passive air sampler for gaseous mercury (Hg) uses a radial diffusive

barrier to control uptake kinetics and sulfur-impregnated activated carbon as a sorbent. An initial

outdoor calibration in Toronto revealed highly linear uptake over a one-year period and

unprecedented precision. The accuracy of this sampler depends on the extent (i) of the variability

of its sampling rate SR (i.e. the volume of air stripped of mercury per unit of time) between

different deployment locations and periods, and (ii) to which it will be possible to account for that

variability. We addressed this issue two-fold. On the one hand, we measured uptake in passive

samplers deployed for up to one year at 22 locations with ongoing active sampling for mercury

around the world. The sites in Canada, USA, Australia, China, Germany and Taiwan varied

widely in terms of climate (tropical to polar regions) and concentration levels. On the other hand,

we quantified in the laboratory how the SR varies with tightly controlled temperature, wind speed

and relative humidity. The results in either case confirm that the SR of the sampler varies only to

a minor extent and the variability is predictable. When accounting for this variability, the sampler

can discriminate even very small concentration differences on the order of 0.2 ng/m3. Successful

early applications of the new sampler include (i) the detailed characterization of the spatial and

temporal variability of Hg concentration around a major known source, which allows for long

term exposure assessment of the local population and for the estimation of a Hg emission rate,

(ii) the identification of unknown Hg emission sources within urban conglomerations, (iii) the

reliable quantification of the isotopic signature of atmospheric Hg.

Figure: Scale diagram of gaseous Hg

Passive air sampler. (A) PTFE screw

cap; (B) activated carbon sorbent; (C)

diffusive barrier; (D) protective

shield; (E) interchangeable cap

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Tryptophan and Serotonin in

the Food System

Diet Metabolism

Mind Culture

Biological Analysis

Literature Review

Interviews with Cree

Environment

Session 1 – Thu. 10:45 am – Chairs: Maryam Abdinejad & Patricia Miller

“We’ve Been Put to Sleep”: Psychological Resiliency in Indigenous Food Systems

Nicole Spiegelaar and Leonard Tsuji

Remote indigenous communities of northern Canada have disproportionately higher incidences

of mental health struggles due to abusive practices in the colonial residential schooling system.

This was paralleled by an abrupt transition from an autonomous and communal subsistence in the

ecological environment, to an externally imposed, import-based and nutrient-deficient

commercial food system. I work with the indigenous Cree of the James Bay region whose

subjective well-being is synonymous with the health of the land and is enhanced by an ability to

participate in traditional food practices. With the Cree, I am developing a mental health

framework that is compatible with indigenous notions of well-being: Ecosystems Psychology.

Today I will provide an example of my approach using the neurotransmitter serotonin, which is

responsible for regulating mood, energy and adaptive response to stress. I have previously found

that aspects of the modern food system limit serotoninergic regulation in the brain. By placing

this molecule in the context of Cree food system transition, I will demonstrate the interplay

between biological, cultural and ecological components of the modern food system that degrade

indigenous identity and psychological resilience. The model as a whole prompts further

investigation of the complex interaction between biological and cultural components within the

ecological environment that continue to instill a greater sense of well-being for the Cree and other

indigenous communities.

COFFEE BREAK – 11:00am – 11:30am

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Session 2 – Thu. 11:30 am – Chairs: Nasrine Mostafavipak & Paris Ning

Can a Moth Strangle the Dog-strangler? An Experimental Application of Hypena

Opulenta as a Biological Control Agent for the Invasive Dog-strangling Vine

(Vincetoxicum Rossicum)

Stuart W. Livingstone, Marc W. Cadotte, Marney E. Isaac

The highly invasive “Dog-strangling vine (DSV)” (Vincetoxicum rossicum) continues to disrupt

native ecosystems across southern Ontario. Thus far, physical and chemical control efforts have

largely proven to be impractical. Here, we perform an experimental application of Hypena

opulenta to examine its potential as a biological control agent. We conducted our study in

Kirkfield, Ontario in highly invaded forest understory and full sun plots. We asked; 1) does

defoliation of DSV by H. opulenta vary in different light conditions, and 2) how does that

defoliation affect DSV’s seed production. Based on previous laboratory work, we hypothesized

that; 1) defoliation of DSV by H. opulenta will be significantly greater in forest understory plots,

and 2) seed production will be significantly reduced in both light conditions, with greater

reduction in the forest understory. Using several metrics, our results indicate that indeed

defoliation of DSV was significantly greater in the forest understory. Though, contrary to our

expectations we did not measure a reduction in seed production in either light condition. In fact

we measured a significant increase in seed production across multiple seed parameters in

defoliated understory plots. Mean seed mass, seed count, follicle mass and follicle length

increased by 31%, 23%, 19% and 16%, respectively. These results reveal a significant

compensatory growth response by DSV to defoliation by H. opulenta. We show that while H.

opulenta is a promising biological control agent for DSV, a self-sustaining population of the

control agent needs to establish in order to see significant reductions in DSV abundance.

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Session 2 – Thu. 11:45 am – Chairs: Nasrine Mostafavipak & Paris Ning

Ekman Boundary Layers in a Large-Scale Gravity Current Experiment

Shahrzad Davarpanah Jazi and Mathew Wells

Oceanic density currents such as contourite currents and turbidity currents can be strongly

influenced by Coriolis forces. Coriolis forces lead to Ekman boundary layers, which result in

transverse secondary flows of as much as 10% of the primary flow (Cossu et al., 2010). For flows

in sinuous channels these Ekman boundary layers can either act with, or against, the secondary

flows driven by centrifugal forces. These secondary near-bed flows are responsible for many of

the details of sediment erosion and deposition in contourites, as well as in larger channels formed

by turbidity currents (Cossu et al., 2015). The magnitude and direction of flows in the Ekman

boundary layers can be defined by a Rossby number, RoW =U/Wf, where U is the mean

downstream velocity, W is the width of the channel and f is the Coriolis parameter. Flows with

Rossby numbers less than 1 are dominated by Coriolis forces and have strong Ekman boundary

layers dominating secondary circulation. A new finding is that even when the Rossby number is

of order 10, there is an appreciable influence of Coriolis forces, supporting empirical observations

of straighter turbidite channels when |RoW| < 10 (Wells et al., 2013). We will present new results

of changes in velocity structure in a very large-scale gravity current from a series of laboratory

experiments on the large Coriolis platform in Grenoble, France.

Figure: A picture of the Plexiglass channel located inside the 13 m rotating table at the large Coriolis facility in Grenoble, France.

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Session 2 – Thu. 12:00 pm – Chairs: Nasrine Mostafavipak & Paris Ning

Calcification on Mortar by Live and UV-Killed Biofilm-Forming Cyanobacterial

Gloeocapsa PCC73106

Tingting Zhu and Maria Dittrich

Microbial carbonate precipitation by phototrophic cyanobacteria in mortars enhances their

durability. This study investigated the calcification by cyanobacteria Gloeocapsa PCC73106 in

mortars. The calcium concentration and the pH were monitored, the carbonate precipitates were

observed, and the performances of cubes were evaluated. Treatments with live cells under

illumination resulted in the largest amount of precipitates, while UV-killed cells contributed to

the highest compressive strength, the least water absorption and the lowest porosity. The

morphology of precipitates differs greatly under different conditions. This is the first study

showing that UV-killed Gloeocapsa PCC73106 can be a potential candidate for improving the

performance of mortars.

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Session 3 – Thu. 12:15 pm – Chairs: Ye Tao & Katherine Balasingham

The ‘Responsiveness Gap’ in Regional Fisheries Management Organizations

(RFMOs): The Critical Role of Decision-Making Policies in the Fisheries

Management Response to Climate Change

Brian Pentz and Nicole Klenk

The impacts of climate change, owing to their potentially vast reach and scale, embody a critical

challenge for fisheries management organizations. We conduct a systematic literature review to

present an overview of how the peer-reviewed academic literature recommends fisheries

management frameworks should respond to the climate change-driven uncertainty, vulnerability

and risk facing resource bases. Our review identifies 21 different potential management

responses. Adaptive management was the most commonly identified strategy, with institutional

capacity development and input/output controls also frequently cited. We contrast our findings

with illustrative cases characterizing management practice and outcomes in RFMOs, and argue

that the ability of RFMOs to implement the climate change mitigation strategies identified in our

review is a function of an organization’s decision-making rules. We argue that consensus-based

decision-making policies limit adaptiveness, and that a ‘responsiveness gap’ exists between

consensus and majority-based decision-making frameworks. This gap will become more evident,

and increase in importance, as the impacts of climate change shift from potential to kinetic.

Considering that decision-making rules in RFMOs are unlikely to change, we argue that increased

analytical effort concentrated on institutional contexts and member state interest complexes may

promote adaptive management, expediting the pace at which scientific recommendations and

findings inform policy and practise in RFMOs.

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Towards Real-Time Environmental Toxicology Using a Low Volume in Vivo NMR

Flow System

Maryam Tabatabaei Anaraki and André J. Simpson

Metabolomics is quantitative and qualitative analysis of biological small molecules within

biofluids, cells, or tissues. This powerful technique has emerged as an important field of

environmental research aimed at understanding the biochemical changes that occur in an

organism in response to environmental stressors such as exposure to potentially toxic

contaminants. In general, metabolomics is a dominant approach for environmental researches

such as in vivo toxicity, bioaccumulation, and mode of action studies of contaminants. In vivo

NMR spectroscopy is a particularly powerful technique, since it allows living samples to be

analyzed in their natural, unaltered state, a criteria paramount for observing real-time

metabolomic changes. In this study, a continuous low-volume flow system built in-house, suitable

for real-time in vivo NMR metabolomics (ex. sub-lethal in vivo toxicity studies or feeding

studies), is demonstrated. This system allows for faster and easier lock, shim, and water

suppression, besides allowing the use of trace amount of expensive toxic contaminants. Using the

flow-system, living organisms can be kept alive without stress during the experiments. To

evaluate the feasibility and applicability of the flow system, changes in the metabolite profile of

20 live, 13C enriched Daphnia magna (water flea) over a 48-hour period are monitored, while

keeping them in two different conditions: with and without food (algae). Using this technique,

this is a first step towards the better practice for environmental toxicity studies and evaluation of

several different environmental contaminants.

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Oxidative Processing Studies on Biological Ice Nucleating Particles

Ellen Gute and Jonathan P.D. Abbatt

Ice nucleating particles (INPs), such as mineral dust, soot, and biological particles, play an

important role in cloud formation as they can form ice crystals in the atmosphere. These ice

crystals contribute to the overall impact clouds have on the Earth’s climate, by affecting

precipitation and the radiation budget of the atmosphere. Chemical exposure to oxidants such as

OH or ozone may impact the ice nucleation ability of INPs. There is evidence that biological

particles, such as bacteria, fungi and pollen represent a major part of atmospheric particles.

However, little is known about their change of ice nucleation ability due to chemical processing.

In this project, we studied the effect of aqueous OH oxidation on the ice nucleation activity of

two types of pollen: Silver Birch and Sycamore Maple. The ice nucleation activity of the

biological material was compared to Arizona Test Dust (ATD) as a typical non-biological

material that is known to efficiently nucleate ice. The ice nucleation activity was measured using

the UofT – Continuous Flow Diffusion Chamber (UT-CFDC). Particles were exposed to OH in

the liquid phase, atomized and dried with a diffusion drier before being size selected and injected

to the UT-CFDC. The ice nucleation activity was measured for 233 K. It was found that only the

Silver Birch pollen exhibited ice nucleation activity in the deposition freezing mode. This ice

nucleation activity could be altered through exposure to OH. In contrast, ATD did not show any

loss of ice nucleation activity due to exposure to OH.

Figure: The observed activated fraction of Silver birch pollen. The Crossed-

line shows the activated fraction at 233K for pure pollen solution. While the dots clearly indicate the activation to decrease when the pollen are exposed to

OH for 4 hours.

LUNCH BREAK – 1:00pm – 2:00pm

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Session 4 – Thu. 2:00 pm – Chairs: Cindy Yang & Ellen Gute

Inuit Knowledge of the Cumulative Impacts of Environmental Change in Eastern

Hudson Bay

Megan Sheremata, William Gough, and Gita Ljubicic

The waters and ice systems of eastern Hudson Bay are central to the lives and livelihoods of

coastal Inuit communities. The effects of hydroelectric development and climate change in the

region have had significant impacts on these communities. This research documents Inuit

knowledge of the cumulative impacts of environmental change in eastern Hudson Bay

communities over the past 40 years. Semi-directed interviews with Inuit elders and hunters are

conducted. The results are analyzed to understand changes in salinity, temperature, currents, sea

ice processes, climate, and weather patterns. Participatory mapping methods used in the study are

critically evaluated to explore the role of mapping tool selection in documenting Inuit knowledge.

Results of this study are presented to communities in collaboration with community researchers,

where community priorities for future research and policy are documented, and additional

interviews with community and regional leaders are conducted. Results are then interpreted to

understand the implications of Inuit observations in terms of land use and climate policy.

15


Analysis of Barotropic and Baroclinic Derived Flushing in Two Large

Embayments in Southern Ontario

Bryan Flood and Mathew Wells

Persistent late summer hypolimnetic dissolved oxygen minima in Kempenfelt Bay, Lake Simcoe

and sporadic fish die-off in aquaculture farms in Parry Sound, Georgian Bay have motivated us

to investigate the physical phenomena controlling the exchange of water between the embayments

and main basins, which have a strong influence on water quality. Parry Sound (Area ~ 92 km2,

Vol ~ 109 m3) and Kempenfelt Bay (Area ~ 34 km2, Vol ~ 6.8*108 m3) are different in size, and

have vastly different geometries giving rise to distinct fluid dynamics. Using thermistor chain and

ADCP field data from 2015 and 2016, we will present a quantitative analysis and comparison of

the dominant flushing mechanisms in the two embayments, along with estimates of their

respective flushing rates. Preliminary results indicate that despite significantly different internal

wave dynamics, internal waves (baroclinic forces) are up to ten times more effective at flushing

than surface waves (barotropic) at both sites. These results will be useful in developing accurate

water quality models and understanding the temporal and spatial variation of fish habitat for the

aquaculture industries in Parry Sound and fish monitoring programs in both study sites.

Figure: Schematic of the development and propagation of an internal wave

influenced by the Earth’s rotation in Kempenfelt Bay, Lake Simcoe.

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The Biogeochemical Role of Dolomite Forming Microbes Isolated From a Kuwaiti

Sabkha

Ammar Al-Ibrahim and Maria Dittrich

Dolomite [CaMg(CO3)2] is an important rock for hydrocarbon exploration that is characterized

by high porosity and permeability. Despite centuries of research, the origin of dolomite remains

one of the most debated subjects in sedimentary geology often referred to as “the Dolomite

Problem”. This problem stems from: a) the inability of precipitating dolomite in abiotic

laboratory experiments simulating the environmental conditions where dolomite is found and b)

the abundance of dolomite within Precambrian sedimentary rocks yet scarcity in younger

sediments. Surprisingly, microbes were found to be a key players in dolomite formation, but the

exact microbial role is currently inconclusive. In the State of Kuwait, dolomite was screened in a

microbial mat sampled from a hypersaline water body called (Sabkha) preserved for over 12 years

in a laboratory and the results were positive for its presence. Thus, the question is: How and which

microbial consortia can form dolomite? Answering these questions will greatly help geologists

and petroleum engineers in better planning, exploration and management of hydrocarbon

resources. Different approaches will be used to understand the microbial role in dolomite

formation including:

1. Cultivating different consortia of the microbial mat to screen dolomite formation

2. Consortia successful to form dolomite will be incubated under different conditions to

understand the effect of these conditions on microbial metabolism

3. Isolation of dolomite-forming microorganisms in pure cultures for molecular

identification

4. Metagenome and metatranscriptome analyses will be applied to study microbial

diversity and functionality related to dolomite formation

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Session 5 – Thu. 2:45 pm – Chairs: Linh Viet Nguyen, Emily Chenery & Yuchao Wan

Whole Genomic and Functional Analyses of Bacterial Endophytes Isolated from

Plants Growing in a Natural Oil Seep Soil

Rhea Lumactud and Roberta Fulthorpe

Bacterial endophytes are known for their beneficial characteristics, such as, plant growth

promotion, pathogen control and contaminant degradation. We explored the metabolic profiles

and biotechnological potential of the genomes Plantibacter flavus 251 and Microbacterium

foliorum 122, which were present on all the sampled plants growing in a heavily petroleum

hydrocarbon contaminated soil at Oil Springs, Ontario. Genomic DNA of these bacteria were

subjected to sequencing on PacBio platform and reads were assembled de novo. Genome

annotation was conducted using RAST web server. Both P. flavus 251 and M. foliorum 122

showed subsystem carbohydrates as the highest feature counts, highlighting an endophytic

lifestyle targeted to plant sugars. Genes that contribute to environmental fitness, such as,

resistance to cobalt, mercury, cadmium and zinc were present in the two genomes. Despite

demonstrated utilization of toluene, no known genes for classical toluene, naphthalene and

biphenyl metabolism were found in the P. flavus 251 and M. foliorum 122 genomes, except for

genes involved in catechol, salicylate and benzoate degradations. The genes for 1-

aminocyclopropane-1-carboxylate (ACC) deaminase, which helps plant tolerate contaminant-

induced stress by decreasing stress ethylene production, was present in P. flavus 251. The genes

involved in the biosynthesis of indole-3-acetic acid, an important hormone in plant growth and

development, were detected in M. foliorum 122. It is hoped that these genomes will provide

insights into improving contaminant degradation for phytoremediation, further elucidate bacterial

adaptation to plants particularly in relation to its colonization and plant growth promotion, as well

as potential exploitation for other biotechnological applications.

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Quantifying the Equilibrium Partitioning of Substituted Polycyclic Aromatic

Hydrocarbons in Aerosols and Clouds using COSMOtherm

Boluwatife Awonaike and Frank Wania

Functional groups attached to polycyclic aromatic hydrocarbons (PAHs) can significantly modify

the environmental fate of the parent compound. Substituted PAHs (SPAHs) elicit interest because

of their toxicity and their ability to absorb UV-VIS radiation. The potential health effects and the

radiative properties of SPAHs depend on their distribution between the gas and particle phase in

the atmosphere. Equilibrium partition coefficients, which are essential for describing a

compound’s environmental phase distribution, are largely unavailable for these compounds.

Based on their molecular structures, COSMOtherm, a quantum-chemical software is used to

estimate the atmospherically relevant partition coefficients between the gas phase, the aqueous

bulk phase, the water surface and the water insoluble organic aerosol phase, as well as the salting-

out coefficients, for naphthalene, anthracene, phenanthrene, benz(a)anthracene, benzo(a)pyrene

and dibenz(a,h)anthracene and 62 of their substituted counterparts, including alkyl, nitro and

hydroxyl substituents. These coefficients serve as input parameters for the calculation of

equilibrium phase distribution of these compounds in aerosols and clouds – particles present in

the atmosphere which differ in size and composition. The effect of salts, the adsorption to the

water surface and the dissolution in a bulk aqueous phase can be safely neglected when estimating

the gas-particle partitioning of SPAHs in aerosols. However, for small PAHs with more than one

polar functional group the aqueous phase can be the dominant reservoir in a cloud.

Simplified Molecular-Input Line-

Entry System (SMILES)

Spatial data files

(.sdf)COSMOconf

COSMOtherm

KW/G, KS/G, KWIOM/G and KS at 25oC.

19


Temporal and Spatial Evolution of Hudson Bay Sea Ice (1971-2011)

Slowamir Kowal, William Gough and Ken Butler

Previous research has found Hudson Bay seasonal sea ice particularly sensitive to climate change

with a strong signal of earlier breakup dates. This work extends the analysis to include eight more

years of sea ice data now spanning 1971 to 2011. Additionally, a spatial analysis using a grid of

36 locations in the Bay was performed. The expanded record revealed stronger and more

statistically significant trends than the earlier research. The average magnitude of the trend for all

36 locations for earlier breakup is 0.50 days per year, for later freeze-up it is 0.46 days per year

and for a longer ice free period it is 0.91 days per year. Furthermore, parts of the Bay have

experienced acceleration in the temporal trends for the three metrics. Twelve points for the

breakup period, 30 points for the freeze-up period and 22 points for the ice free season have

accelerating temporal trends. The spatial analysis was done using clustering statistics. Clusters of

sea ice data points were found to be consistent with observed patterns of sea ice breakup and

freeze-up. Two clustering methods (Ward’s and K-means’) produced consistent results with some

small variations. Clustering along the coasts for all three metrics had the greatest coherency

suggesting that the connection with the shoreline provided a constraint that enabled the ice within

a cluster to act in a coherent fashion. There was less consistency in clustering of points in the

central regions and the two methods differed in this regard, but not substantially.

Figure: Hudson Bay with a Grid of 36 Sampling Points

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Preliminary Assessment of Asian Carp Spawning Potential in Canadian

Tributaries to Lake Ontario

Tej Heer, Mathew Wells and Nicholas Mandrak

Four invasive fish species, known collectively as Asian carps, are on the verge of invading the

Great Lakes. Prevention efforts, such as rapid-response and early monitoring programs, require

knowledge of where carps are likely to spawn. A preliminary assessment, using data from 2009

to 2014, was completed to predict the suitability of Toronto-area tributaries for Asian carp

spawning. The assessment estimates the time of year of potential spawning and the river length

required for successful spawning using daily velocity and temperature data. The results of this

assessment show high inter-annual variability in spawning suitability. On average, only two

tributaries are suitable; however, in 2012, almost all of the tributaries were suitable due to higher

water temperatures, with a high-flow event needed to trigger spawning. This assessment uses

more robust data than previous assessments to highlight substantial inter-annual variation in

suitability for Asian carp spawning. The results of this preliminary assessment will be used to

identify tributaries that require detailed analysis using more rigorous hydrodynamic models.

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END OF DAY ONE

NOTES:

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Session 1 – Fri. 10:15 am – Chairs: Maryam Tabatabaie Anaraki & Raul Salas Reyes

Quantification in Multiphase Samples by Comprehensive Multiphase NMR Using

Stepped Decoupling

Paris Ning and Andre Simpson

Environmental and biological samples can be complex in nature comprising of multiple phases.

Studying these samples intact is important as it is often the synergistic interaction between

chemical components in different phases that give rise to structural properties and reactivity.

Recently, comprehensive multiphase nuclear magnetic resonance (CMP-NMR) was introduced

that combines all the hardware features required to analyse multiphase samples. Quantification in

NMR is possible but traditionally two different approaches are used to quantify solid and another

solution. In solids intense radiofrequency decoupling is required to decouple protons (from

carbons) permitting accurate integrals to the obtained for the carbons. However, high power

decoupling can only be applied for milliseconds otherwise the NMR coils and probe components

melt. Conversely in solutions decoupling is applied for many seconds at low power to achieve

quantification. In multiphase samples that contain both solids and liquids neither method alone is

adequate. In this study, we introduce a decoupling technique, named stepped decoupling

(step_dec) that works under current hardware limitation and is suitable for multiple phases

(solution, gel and solid). A series of samples, including model mixtures, soil, and plant leaves,

were analysed using stepped decoupling and the results were compared with the conventional

high-power decoupling (hpdec) technique used for solid samples. Figure 1 below shows the

comparison of 13C spectra of isotopically labelled broccoli leaves under hpdec and step_dec.

While the peaks from solid component show no difference, the peaks from components in solution

phase are better resolved under stepped decoupling.

Figure: 13C labelled broccoli leaves in natural state. Peaks from soluble metabolites are well-resolved (Figure

1A, i, iv and v) and show no truncation under stepped decoupling (Figure 1A, ii) while under high-power

decoupling with a shortened acquisition time, the peaks are less resolved (Figure 1B, i, iv, and v) and

truncation can be seen (Figure 1B, ii and iv). The general profile of the broccoli, in large part arising from the

more rigid components of broccoli leaves, shows no discernable differences when the two decoupling

23


Diversity of Fishes in the Amazon: How Different Water Types Might Drive the

Evolution of Adapted Fish Groups

João Pedro Fontenelle and Nathan R. Lovejoy

The rivers of the Amazon divide into high-conductivity systems (comprising sediment-rich white

waters) flowing out of Andean erosion zones, and low-conductivity systems, comprising black

water systems (high in humic acid and low in sediments) draining lowland Cenozoic formations

and clear water systems (with intermediate sediment composition) draining Paleozoic formations.

In addition to conductivity, other physicochemical properties of the river water vary among these

“river colours”, such as pH, temperature, sediment concentration, water transparency, to name a

few. These environmental variables might act as “selective barriers” to some fishes, isolating

populations and impeding gene flow, which would eventually cause differential evolution and

speciation, as we can observe in the impressive diversity of Amazonian fishes. To investigate the

influence of environment over evolution, we chose two different groups of fish that evolved

exclusively in the Amazon and are highly adapted to their environments: Electric fishes from the

order Gymnotiformes produce electric fields, used for navigation and communication, which are

affected by the water conductivity; and freshwater stingrays from the subfamily

Potamotrygoninae, which also have a system for interpreting electric signals from the

environment, in addition to osmoregulation and sight. We use a molecular approach to generate

relationship hypotheses for the group and statistically test for effects of the environment over the

molecular distances, in relation to their geographical distances. We also look for biogeographical

patterns and speciation evidence in relation to distinct habitats.

Figure: Hypothetical distinct relationships of

electric fish and stingrays from the Amazon.

24


Molecular Engineering for Efficient and Selective Porphyrin Catalysts for

Electrochemical Reduction of CO2 to Fuel

Maryam Abdinejad, Heinz Bernhard Kraatz and Xiao-an Zhang

One of the biggest concerns in recent years is global warming, which is coming from the

greenhouse gasses in the atmosphere. Carbon dioxide (CO2) is the major greenhouse gas emission

released by human activities such as burning fossil fuels and deforestation, as well as natural

processes and volcanic eruptions that act as a blanket, trapping heat and warming the plants.1

Therefore, the reduction of CO2 into valuable products has environmental economic importance.

Using efficient and low-cost catalysts is one of the best ways to solve this issue by binding to the

carbon centre of CO2 and converting it to carbon-monoxide (CO), which is a main building block

for carbon-based chemical fuels, such as methanol, ethanol and formaldehyde. In the current

project, a series of porphyrin complexes with different types of functional groups as well as their

activities on electrochemical reduction of CO2 to valuable material will be discussed.

COFFEE BREAK – 11:00am – 11:30am

25

Session 2 – Fri. 11:30 am – Chairs: Stephanie Gagliardi & Boluwatife Awonaike

Risk Assessment of Peary Caribou Populations Using Bayesian Inference

Techniques

Samarth Kaluskar and George Arhonditsis

Peary caribou (Rangifer tarandus pearyi) are a major component of the Canadian High Arctic’s

(CAA) biodiversity and a vital resource for High Arctic Inuit communities. Changing conditions

in the CAA may affect the integrity of this endemic species population. The proposed research

on population dynamics has four major objectives, aiming: i) to determine the accuracy of existing

population estimates along with the associated precisions in the broader CAA area; ii) to build

regression model for infilling Peary caribou data whenever the population is missing at random;

iii) to build a spatial-explicit Peary caribou models that will allow gaining insights into the

interplay between environmental stressors and animal behavioral patterns in both local and

regional scales iv) to build a spatial-temporal model that will downscale Peary caribou population

at a local scale, while gaining insights into the interplay between environmental stressors and

animal behavioral patterns. We developed four models to predict Peary caribou population. We

used Bayesian inference technique to calibrate the four models. The Bayesian calibration

methodology offers several technical advances, such as alleviation of the identification problem,

sequential updating of the models, realistic uncertainty estimates of ecological predictions, and

ability to obtain weighted averages of the forecasts from different models, that can be particularly

useful for environmental management. In order to better predict or improve the accuracy of the

four model predictions, we will synthesize the results into a single score using Bayesian ensemble

averaging. The aim is not to choose the ‘‘best’’ model, but rather to incorporate the insights and

knowledge implicit in various forecasting efforts via statistical post processing. Lastly using

population downscaling, we would like to delineate preferred and avoided habitats, important

forage resources, and amount of habitat (including ice-crossings) used seasonally by Peary

caribou within their defined distribution. The spatiotemporal projections derived from the

Bayesian infilling and observations will be linked to critical habitat characterization framework

in order to downscale the Peary caribou population from regional (spatial complex-based) to local

(1 x 1 km) scale and to delineate the relationship between biophysical attributes and Peary caribou

abundance during the summer season.

26

Session 2 – Fri. 11:45 am – Chairs: Stephanie Gagliardi & Boluwatife Awonaike

An In-vivo Hetero-nuclear NMR Spectroscopy Investigation to Detect and

Understand Biological Process

Yalda Liaghati Mobarhan and Andre J. Simpson

Nuclear Magnetic Resonance (NMR) based metabolomics is a leading tool for environmental and

biomedical research fields. It has potential to revolutionize disease diagnosis and identifying

environmental stress by explaining which biochemical pathways are affected thus explaining why

chemicals are toxic1, 2. Monitoring metabolites at low concentrations and in real-time is more

feasible if they contain an NMR active heteronucleus such as 31P that acts as a probe to be studied

selectively. 31P NMR has been applied to study energy metabolism in tissues, organs and

organisms3. The use of stable isotopes (13C or 2H, 15N) incorporated into the food or stressor

makes NMR spectroscopy the method of choice for exploring the metabolic pathways. For

example 13C NMR has been established as the method of choice to observe metabolomic fluxes

among healthy and tumor cells4.Previously we demonstrated that comprehensive multiphase

(CMP) NMR5 could be applied to study all components in an intact organism6. In this study, the

organisms are exposed to stable isotope (15N, 13C, 2H) enriched food sources or contaminants

containing such nuclei, the incorporation of hetero- nuclei into H. Azteca is investigated in vivo,

using two approaches:

1) The first approach focuses on following the organism itself. Such studies explain how

an organisms is impacted by its environment at the metabolic level.

2) The second approach studies the fate of xenobiotics (contaminants or drugs) inside

living systems. Such studies help explain the biotransformation and bioaccumulation

of chemicals.

Such information will provide a unique window into the metabolic pathways, carbon transfer and

growth processes7.

Figure: 13C NMR spectra highlighting

utilization of 13C enriched algae by H.

azteca. A. dotted line the algae prior to feeding the H. azteca and solid line

after 6 hrs of feeding on the algae B)

Algae dotted line(start) and solid line (6hrs) without shrimp present; these

spectra are near indistinguishable,

showing that changes arise from the

conversion by H. azteca.

27

Session 2 – Fri. 12:00 pm – Chairs: Stephanie Gagliardi & Boluwatife Awonaike

Seeds of Change: The Role of Seed Endophytes in the Plant Microbiome

Patricia Anne Miller and Roberta Fulthorpe

Plants have a complex microbiome that includes both bacteria and fungi. Bacterial endophytes

are important members of the plant holobiont as they positively influence plant growth and

responses to pathogens and abiotic stresses. Plant microbiome research is a newly developing

field with many unanswered questions. A pressing and current question remains about the source

of bacterial endophytes. Studies suggest that plants derive their bacterial endophytic communities

from the soil, the atmosphere, and the seed endosphere. The relative contribution of these sources

has not yet been assessed. If seeds, however, determine the endophytic content of adult plants,

then their origin is of great importance to agricultural practices. We are currently examining seed

endophytes of various food plants, comparing the content of “organic” versus conventional seed

sources. Endophytic populations of stems and leaves are also being compared to their seeds for a

subset of these plants grown under laboratory and field conditions, using culture dependent and

independent methods. Preliminary results suggest that plants have a high diversity of endophytes

throughout and that seed endophytes are also found in other plant parts. Further comparisons are

expected to shed light on the contributing role of seed endophytes in the plant microbiome.

28

Session 3 – Fri. 12:15pm – Chairs: Andrew Apostoli & JP Fontenelle

Development of a Methane Emission Inventory for the Greater Toronto Area

Nasrin Mostafavipak and Debra Wunch

As part of Canada’s action plan on climate change, the Government of Ontario has set an

ambitious target to reduce Greenhouse Gas (GHG) emissions to 80% of 1990 levels by 2050.

Methane (CH4) is an important GHG, second in abundance to carbon dioxide (CO2), but with 25

times global warming potential. In addition, it is generally more feasible to cut CH4 emissions

with zero cost or even profit compared to CO2. In order to meet the proposed GHG reduction

target, a thorough understanding of CH4 emissions and its main sources in large urban areas is

needed. This can be obtained by an emission inventory quantifying and identifying CH4 emissions

by source category. The Government of Canada prepares a GHG emission inventory for Canada

annually, which includes total CH4 emissions by sector. However, a more refined emission

inventory that is both specific to the Greater Toronto Area (GTA) and spatially resolved is

missing. In this presentation, the development of a CH4 emission inventory for the GTA that

reports the total emissions from the city and the disaggregated emissions by sector and geographic

region will be presented. We will then introduce our plan to verify the total CH4 emissions using

total column measurements and to identify major sources using ground level mobile

measurements. In addition, we will discuss how the emission inventory will be improved using

an air dispersion model to generate CH4 concentration fields and comparing the model results

with our measurements.

29

Session 3 – Fri. 12:30 pm – Chairs: Andrew Apostoli & JP Fontenelle

Impact of Energy Retrofit Measures on Indoor SVOCs: A Pilot Study

Yuchao Wan, Jeffrey Siegel and Miriam Diamond

To meet energy efficiency standards, energy retrofits, as opposed to rebuilding, have become the

preferred option for reducing the carbon footprint of existing buildings. Energy retrofits are

ongoing for several multi-unit residential buildings (MURBs), built in Toronto between 1965 and

1974. In order to assess indoor air quality monitoring packages including a portable air cleaner

have been installed in 71 MURB units. A pilot study was conducted in a single apartment to test

whether the portable air cleaner can be used to collect samples for indoor semi-volatile organic

compounds (SVOCs) analysis. In the pilot study, a portable air cleaner was installed in the test

apartment, along with the long-term monitoring package (consisting a CO2 sensor, an Onset

HOBO U12-012 and an Onset TMCx-HD temperature probe) and a passive air sampler for

SVOCs. That passive air sampler consisted of polydimethylsiloxane (PDMS). Filter samples from

the portable air cleaner were collected after 7 days and analysed by GC-MS. Potential

contamination of the portable air cleaner and monitoring packages was tested for using surface

product wipe samples and through the deployment of PDMS samplers with the devices. Results

suggested that the monitoring packages would not introduce SVOCs of interest, namely

brominated flame retardants (BFRs) and phthalates. Conditioning the filter from portable air

cleaners would not contaminate the filter with target compounds. The filter contains small

amounts of some BFRs and phthalates. The pilot study showed that the portable air cleaner can

be used to assess indoor air quality from the perspective of SVOCs.

30

Session 3 – Fri. 12:45 pm – Chairs: Andrew Apostoli & JP Fontenelle

Observations of Nitrogen Oxides Fluxes above the Forest at UMBS

Qianwen Shi and Jennifer Murphy

Nitrogen oxides (NOx = NO + NO2) produced from both natural and anthropogenic processes are

considered as important constituents in the global atmosphere because of their reactivity and

strong connection to ozone (O3) and hydroxyl radical (OH). Deposition and emissions of NOx to

and from an ecosystem can influence its nitrogen budget, but direct flux observations of NOx are

difficult and rare. Forests cover about 30% of the Earth’s land surface and are important in terms

of regulating climate through albedo effects, evapotranspiration, carbon sequestration, as well as

the exchange of reactive trace gases. The decline of anthropogenic NOx emissions across North

America and Europe due to air quality concerns is expected to change the deposition of nitrogen

to sensitive forest ecosystems. Therefore, to understand the exchange of NOx between the forest

and the atmosphere, it is important to conduct direct measurements of NOx exchange above the

canopy. During the summer of 2016, NOx mixing ratios and fluxes were measured on the

PROPHET tower located in the forest at University of Michigan Biological Station (UMBS). The

mixing ratio of NO ranged from 0 to 640 ppt while that of NO2 ranged from 68 to 3600 ppt.

Fluxes calculated by the Eddy Covariance method showed an upward flux of NO2 and a

downward flux of NO, indicating chemical flux divergence resulting from fast chemistry and

diminished solar radiation below the canopy. To calculate the net exchange of NOx between the

atmosphere and the forest requires careful data quality control.

Figure. Five-minute averaged mixing ratios of NOx above the forest at UMBS during July 2016

LUNCH BREAK – 1:00pm – 2:00pm

31

Session 4 – Fri. 2:00 pm – Chairs: Andrew Zaich & Qianwen Shi

A Comparison of Climatological Observing Windows and Their Impact on

Detecting Daily Air Temperature Extrema

Ana Žaknić-Ćatović and William Gough

Climatological observing window (COW) is defined as a time frame over which continuous or

extreme air temperature measurements are collected. A 24-hour time interval, ending at 00UTC

or shifted to end at 06UTC, has been associated with difficulties in characterizing daily mean

temperature extrema. A fixed 24-hour COW used to obtain the temperature minima leads to

potential misidentification due to fragmentation of “nighttime” into two subsequent nighttime

periods due to the time discretization interval. The correct identification of air temperature

extrema is achievable using a COW that identifies daily minimum over a single nighttime period

and maximum over a single daytime period, as determined by sunrise and sunset. Due to a

common absence of hourly air temperature observations the accuracy of the mean temperature

estimation is dependent on the accuracy of determination of diurnal air temperature extrema.

Qualitative and quantitative criteria were used to examine the impact of the COW on detecting

daily air temperature extrema. The timing of the 24-hour observing window occasionally affects

the determination of daily extrema through a mischaracterization of the diurnal minima and by

extension can lead to errors in determining daily mean temperature. Hourly air temperature data

for the time period from year 1987 to 2014, obtained from Toronto Buttonville Municipal Airport

weather station, were used in analysis of COW impacts on detection of daily temperature extrema

and calculation of annual temperature averages based on such extrema.

Figure: Diurnal air temperature extreme search using three different climatological observing windows. Shaded regions indicate nighttime (sunset to sunrise), dashed lines indicate midnight while solid yellow lines

indicate noon time (LST). Black solid line represents measured hourly temperatures. Tn corresponds to daily

minimum temperatures and Tx to daily maximum temperatures with 0-24, 6-6 and ND subscripts representing COW0-24, COW6-6 and COWND methods

TxND=Tx24=Tx6

TxND=Tx24=Tx6

TxND=Tx24=Tx6

TxND=Tx24=Tx6

Tn24

Tn24

Tn24

Tn24

TnND

TnND TnND

TnND Tn6

Tn6

Tn6

Tn6

COW 0-24 COW 6-6

COW N-D

NIGHTTIME DAYTIME

32


Preliminary Assessment of Occupational Exposure to Flame Retardants in a

Canadian E-waste Dismantling Facility

Linh V. Nguyen, Victoria Arrandale, Miriam Diamond

The mass of e-waste produced globally is growing dramatically. In response, jurisdictions such

as Ontario have adopted policies to promote safer and environmentally responsible handling of

e-waste. One hazard when handling e-waste is the flame retardants (FRs) added to electronic and

electrical equipment. We have undertaken the first study of occupational exposure to FRs among

e-waste handlers in Canada. Here, we report on concentrations and profiles of selected FRs in

indoor air (n=4) and in dust samples (n=9) collected from an e-waste dismantling facility in

Southern Ontario. Air samples in the facility were collected by co-deploying stationary active and

passive air samplers at the workbenches; dust samples were collected from the floor, workbenches

and bins used to store sorted e-waste. Post-deployment samples were extracted and analysed for

32 flame retardants including novel brominated flame retardants (NFRs), polybrominated

diphenyl ethers (PBDEs) and organophosphorus esters (OPEs) using gas chromatography mass

spectrometry (GC-MS). The most abundant FRs were the now-banned PBDEs (BDE-209

accounted for ~70-90 % in dust and ~90 % in indoor air) and OPEs (TCPP-1 accounted for ~70%

in air and TPhP accounted for ~45% in dust). The levels of “old” FRs such as BDE-209 in floor

dust were 500% higher than was found at e-waste facilities in Southern China and Thailand.

Concentrations and relative abundance of FRs in dust differed between bins containing sorted e-

waste, indicating differences in chemical content by product-types. These results will be used to

estimate FR exposure to e-waste dismantlers at this facility.

33


Exploring the Origins of Drumlins and Megascale Glacial Lineations

Shane Sookhan and Nick Eyles

Current models for the origins of drumlins and mega-scale glacial lineations (MSGLs) are

incapable of adequately accounting for the wide variability in shapes and compositions of

glacially streamlined landforms. Many hypotheses are based off of data that is spatially limited

and often incomplete, with landform populations only partially mapped in detail due to logistical

difficulties. Any comprehensive hypothesis must be able to explain the presence of all drumlins

and MSGLs, which can only be done by greatly expanding the datasets used for modelling. This

presentation outlines techniques which aim to fill the identified data gap in glacial geomorphology

studies by using high resolution elevation datasets to improve the mapping of streamlined

landforms. Demonstrated techniques, such as the Curvature-Based Relief Separation (CBRS)

methodology, have the potential to increase data resolution and shed new light on the relationship

between subglacial processes occurring during episodes of faster ice flow, called ice streams, and

the resultant postglacial geomorphology.

34

Session 5 – Fri. 2:45 pm - Chairs: Ammar Al-Ibrahim, Zachary Di Loreto & Shane Sookhan

Mercury Levels in Herring Gulls and Fish: 42 Years of Spatio-Temporal Trends in

the Great Lakes

Ariola Visha and George Arhonditsis

Total mercury levels in aquatic birds and fish communities have been monitored across the

Canadian Great Lakes by Environment and Climate Change Canada (ECCC) for the past 42 years

(1974–2015). These data (22 sites) were used to examine spatio-temporal variability of mercury

levels in herring gull (Larus argentatus) eggs, lake trout (Salvelinus namaycush), walleye (Sander

vitreus), and rainbow smelt (Osmerus mordax). Trends were quantified with dynamic linear

models, which provided time-variant rates of change of mercury concentrations. Lipid content (in

both fish and eggs) and length in fish were used as covariates in all models. For the first three

decades, mercury levels in gull eggs and fish declined at all stations. In the 2000s, trends for

herring gull eggs reversed at two sites in Lake Erie and two sites in Lake Ontario. Similar trend

reversals in the 2000s were observed for lake trout in Lake Superior and at a single station in Lake

Ontario. Mercury levels in lake trout continued to slowly decline at all of the remaining stations,

except for Lake Huron, where the levels remained stable. A post-hoc Bayesian regression analysis

suggests strong trophic interactions between herring gulls and rainbow smelt in Lake Superior

and Lake Ontario, but also pinpoints the likelihood of a trophic decoupling in Lake Huron and

Lake Erie. Continued monitoring of mercury levels in herring gulls and fish is required to

consolidate these trophic shifts and further evaluate their broader implications.

35

Session 4 – Fri. 3:00 pm – Chairs: Ammar Al-Ibrahim, Zachary Di Loreto & Shane Sookhan

Assessing Nested and Cumulative Chloride Behaviour of a Highly Urbanized

Watershed

Aimé Kayembe and Carl P.J. Mitchell

Urban development significantly alters the landscape by introducing widespread impervious

surfaces, which quickly convey surface runoff to streams via stormwater sewer networks,

resulting in “flashy” hydrological responses. Alongside hydrological changes, occurrence of

increasing chloride concentrations in urban streams of cold climates has raised concerns on its

negative impacts on aquatic and riparian biota. Every year, more than 100,000 tonnes of chloride-

based deicing chemicals are applied on impervious surfaces such as roads, highways, and parking

lots in metropolitan Toronto. Although much of the salt is flushed by overland flow, a fraction is

retained in the sub-surface and eventually released in pulses to streams as baseflow. Whereas the

association between land use and chloride load in watersheds of cold climate regions has received

a particular attention and is widely performed at the watershed level, studies lack that have

assessed nested and cumulative chloride behaviour in subcatchments of a highly urbanized

watershed. An annual chloride budget obtained from high resolution (hourly) continuous

conductivity data coupled with GIS interpretation of landscape characteristics are used to

investigate the cumulative effect of this pollutant in downstream subcatchments of a highly

urbanized watershed (Mimico Creek, Ontario). Early results indicate that drainage connection

(the fraction of impervious area hydraulically connected to the stream via storm water sewer

network) explains most of the variance between chloride loads and imperviousness in the

subcatchments. This study holds important implications for resource managers wishing to

mitigate water quality degradation, it also allows for a meaningful discourse of the influence of

urbanization on stream hydrology and the fate of chloride in highly urbanized watersheds and

their subcatchments.

36


Mining Metagenomes to Study Viral Populations in Hamilton Harbour

Christine Palermo and Steven Short

Metagenomics is a rapidly growing field that has gained popularity as it becomes more powerful,

more affordable and more user friendly. My research involves exploring the viral diversity in a

previously sequenced metagenomic dataset that was used to study the bacterial and eukaryotic

communities in Hamilton Harbour. Gene-based studies of viral ecology have been hindered by

the lack of a universal marker gene such as the 16S gene for bacteria. While the rising popularity

of shotgun metagenomics has helped to unveil the mysterious nature of viral genomes, it has also

highlighted enormous knowledge gaps and the need for a complete re-evaluation of our

understanding of viruses. One of these recent developments is the discovery of “giant viruses”,

which possess genomes larger than some bacteria, including complex genes which have caused

scientists to re-evaluate the evolutionary origins of viruses, and even their non-living status.

Exploration of the Hamilton Harbour dataset shows a diversity of these giant viruses, as well as

a surprising abundance and diversity of a more recently discovered group of viruses that parasitize

giant viruses and benefit the eukaryotic host during infection by the giant virus. Through my

research I plan to document the diversity of these recently discovered viruses in Hamilton

Harbour, establish biweekly changes in the viral communities, and highlight potential virus-host

interactions.

37


Development of an Ecophysiological Daphnia Model to Examine the Interactive

Effects of Nutrition and Methylmercury Toxicity

Felicity Ni and George Arhonditsis

Despite efforts to address issues of mercury in the environment, levels continue to rise,

necessitating rapid and reliable tools in water quality management to mitigate potentially

catastrophic ecosystem shifts. By integrating ecosystem-level models with chemical analysis

tools, we propose a novel bio-indicator technique connecting physiological stress of individual

Daphnia to ecosystem dynamics. Daphnia, a crustacean zooplankton, represents an essential

compartment in aquatic ecosystems, connecting phytoplankton to many fish species. We have

developed a model that aims to elucidate the interactive effects of mercury toxicity and nutrition

(food quality and quantity) on the relationship between phytoplankton and Daphnia through an

understanding of both mass and energetic consequences. Typically, zooplankton modelling

studies on food quality have examined a limited range of macronutrients; we have expanded our

scope to include fatty acids, amino acids, saturated fats, and other nutrients. Our work highlights

that healthy dietary patterns can be critical in ameliorating toxicity, and thus biotic populations

cannot be maintained solely through contaminant management. Our modelling framework links

physiological and biochemical-level processes to ecosystem patterns to provide a deeper

understanding of the interactions between toxicity and food quality and whether food quantity

and quality can mitigate the impacts of mercury toxicity in Daphnia and improve resistance and

resilience against mercury. We offer the prospective of quantitative response indicators in long-

term water monitoring efforts and a framework that can accommodate parameterization from

experimental data. Understanding the responses and linkages between these ecosystem drivers

may improve the management and conservation of the ecosystems contaminated with mercury.

38

END OF DAY TWO

NOTES:

39

NOTES:

40

Thank you to DESC III sponsors:

Dept. of Physical & Environmental Sciences

Special thanks to the Vice Principal Research office for providing support to DESC III.

dept. of physical & environmental sciences · 12:00 - 12:15 tingting zhu zachary di loreto...

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