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Influence Of Landscape And Nutrients On Stable Isotope Dynamics And Food Webs In A River Prior To Re-Establishing Fish Migration, Selina Al-Nazzal

Electronic Theses and Dissertations

Great Lakes tributaries are undergoing major ecosystem restoration through dam removal aimed at improving habitat connectivity. Re-establishing connectivity can have consequences for both desirable and undesirable species, especially in watersheds that risk the invasion of non-native species. To predict and evaluate the effects of reconnecting native fish habitats, I used stable isotopes of carbon (δ13C), nitrogen (δ15N), and sulphur (δ34S), spatial stream network (SSN) models and trophic niche measurements to examine the influence of land cover and nutrient concentration on the trophic ecology and distribution of stable isotopes of biofilm, macroinvertebrates, and fishes in the Boardman/Ottaway River (BOR), a tributary …

Root System Response Of Soybean To Microplastics Of Varying Types And Concentrations, Deqa Farow

Electronic Theses and Dissertations

Biosolid fertilizer use causes the input of microplastics into the rhizosphere where they may interfere with root interactions with the soil and microbial community and thereby hinder plant acquisition of nutrients and water. However, it is unclear what microplastic concentration or types affect plant root system and when these impacts manifest. Using the rhizobox method, soybeans were grown in soil was dosed with microplastic mimics (PET sheets and PP beads at 2,000 and 15,000 particles / kg dry soil) and biosolids. A time-series analysis was conducted on plant root traits using non-destructive imaging with an Epson 12000xl scanner of the …

The Effects Of Biosolid Microplastics On The Microbial Community And Root Functioning In The Rhizosphere Of Soybean Crops In Agricultural Soil, Rebecca Chloe Lebel

Electronic Theses and Dissertations

Biosolids are semi-solid by-products from wastewater treatment plants where contaminants such as microplastics can accumulate, and transfer into the root zone causing ecotoxic effects to the rhizosphere microbial community. Furthermore, microplastics can alter soil properties which have a strong control on the size and diversity of the rhizosphere microbial community and its ability to consume root-borne carbon compounds. Using the MicroRESP system the respiration of the rhizosphere microbial community of soybeans subjected to microplastic biosolid mimics of two types (PET sheets and PPT beads) and two concentrations (2,000 vs 15,000 particles/kg dry soil) was quantified. Baseline respiration rates from extracted …

The Influence Of Spatiotemporal Variation In Food Web Models, Cecilia E. Heuvel

Electronic Theses and Dissertations

Aquatic ecosystems are constantly adapting to fluxes in season, temperature, nutrient cycling, and prey availability. Consequently, aquatic food webs are dynamic, and relationships between species are perpetually changing as organisms and primary producer communities adapt to current environmental conditions both in time and space. Despite this knowledge however, many food web studies continue to use temporally static and spatially homogenous representations of food webs. This thesis proposes that a detailed investigation of temporal and spatial trends in a large lake ecosystem can improve our understanding of the mechanisms and drivers of spatial and temporal variation in food web structure and …

Using Harmonization To Examine Freshwater Mussel Species At Risk: A Sydenham River Watershed Case Study, Julia Ann Willsie

Electronic Theses and Dissertations

There are over 300 species of freshwater mussels (Family: Unionidae) across North America with many populations at risk or in decline. Mussels provide essential ecosystem services, yet they remain largely underexplored in terms of distribution, population sizes, life history traits, and co-existence with hosts, making species conservation efforts a challenge. To advance the conservation of freshwater mussel species at risk of extinction (SAR), this thesis aims to extend understanding of freshwater mussel SAR distributions in a biodiverse but vulnerable watershed in the Laurentian Great Lakes basin. This thesis asks: How can freshwater mussel SAR distribution data be leveraged through existing …

Influence Of Lake Volume On Trophic Position, Carbon Use, And Resource Partitioning In Fish Across A Narrow Range Of Ecosystem Size, Alyssa Andersen

Electronic Theses and Dissertations

Lake size is an important factor governing seasonal variation in limnological phenomena, origin of nutrient sources, species interactions, cross-habitat linkages, and trophic pathways, all having complex influences on food web structure and function. Lake size effects are most clearly demonstrated across very wide gradients in surface area or volume. This approach incorporates several complicating and collinear elements such as changing fish assemblages and species richness, and therefore, incorporates additional but unaccounted shifts in food web structure and function. A comparison across a finer lake size gradient where fish assemblages and species richness change little or not at all is needed …

The Characterization Of Riparian Vegetation In Agriculture Drains Impacted By Phragmites Australis And Drain Management: A Southwestern Ontario, Canada Case Study, Ryan Mackenzie Graham

Electronic Theses and Dissertations

Agricultural drainage systems are important components of regional ecosystems and play key roles in ecosystem functioning. Biodiversity is a service provided by drains which is not fully understood in agriculturally dominated areas and is disrupted consistently by drain management, specifically in drains invaded by Phragmites australis. The objective of this thesis was to characterize the contribution of regional vegetational biodiversity provided by drainage systems, across sites representing a gradient of management frequencies. Drains were separated into management categories: Low (managed +5 years ago), Medium (managed every 3-5 years), or High (managed yearly). Plant abundance was measured and biodiversity indices (Species …

Macroinvertebrate And Bacteria Community Responses To Tributary Inputs At Coastal Wetlands Of The Detroit River, Ontario, Canada, Jessica Robson

Electronic Theses and Dissertations

The Detroit River is a Great Lakes Area of Concern with five monitored wetlands in the Canadian jurisdiction. Habitat assessments have indicated possible stress at wetlands receiving inflow from Turkey Creek and River Canard tributaries. These assessments are made within the tributaries. Yet, macrophyte beds extend into the river upstream and downstream and are important biodiversity habitats. This thesis examines benthic macroinvertebrate and sediment bacteria community compositions for differences with respect to tributaries by two means. First, we examine inter-wetland differences for resemblance to water quality. We had found by NMDS and PERMANOVA that neither taxonomic group resembled water quality …

Assessment Of Water Quality Index, Light Attenuation, And Nutrient Sequestering By Submerged Aquatic Vegetation In The Detroit River, John Scannell

Electronic Theses and Dissertations

This thesis assessed water quality – submerged aquatic vegetation interactions in the Detroit River. Submerged aquatic vegetation provides essential ecosystem services that support aquatic biodiversity and regulating ecosystem services such as carbon sinks, purifying water and nutrient cycling. Chapter 2 explored how degraded water quality in the Detroit River limits submerged aquatic vegetation via light limitation. A water quality index and light extinction coefficients were measured at 21 sites along with installation of in-situ water quality sondes at 4 sites to measure water quality at high temporal resolution. The river wide median euphotic depth was estimated to be 1.30 m, …

The Characterization Of Riparian Vegetation In Agriculture Drains Impacted By Phragmites Australis And Drain Management: A Southwestern Ontario, Canada Case Study, Ryan Mackenzie Graham

Electronic Theses and Dissertations

Agricultural drainage systems are important components of regional ecosystems and play key roles in ecosystem functioning. Biodiversity is a service provided by drains which is not fully understood in agriculturally dominated areas and is disrupted consistently by drain management, specifically in drains invaded by Phragmites australis. The objective of this thesis was to characterize the contribution of regional vegetational biodiversity provided by drainage systems, across sites representing a gradient of management frequencies. Drains were separated into management categories: Low (managed +5 years ago), Medium (managed every 3-5 years), or High (managed yearly). Plant abundance was measured and biodiversity indices …

Sediment Microbial Community Diversity And Function In Response To Legacy And Prevailing Pollutants In Southern Ontario Watersheds, Nicolas Falk

Electronic Theses and Dissertations

Managing and mitigating point and non-point contamination to freshwater resources depends on reliable and sensitive monitoring of ecosystem health. Microorganisms in surface waters and sediments respond rapidly to anthropogenic disturbances, making them valuable bioindicators of human-induced landscape change. However, there lacks a baseline understanding of microbial community composition and function in industrially and agriculturally impacted regions of the Great Lakes. Without a reference state of microbial diversity and activity, future investigations seeking to integrate microorganisms into ecosystem assessments will lack context. Using genomic tools and measurements of chemical and nutrient contaminants, this thesis provides case studies of microbial community responses …

Dynamic Distributed Energy Resources For Expansion Of Ontario’S Greenhouse Sector, Lysandra Naom

Electronic Theses and Dissertations

The vegetable greenhouse sector is rapidly growing and adopting technology advances like supplemental lighting. Supplemental lighting has a dynamic impact on the demand and consumption of a greenhouse’s electricity load. There is uncertainty on the rate of adaptation of technologies and the impact this could have on the power consumption of the sector. Without electricity availability, the sectors innovation and expansion can come to a halt. This research focused on investigating greenhouse electrical load models and lighting trends to forecast demand on electricity grids and discover potential for Distributed Energy Resource (DER) applications.

This thesis presents a series of studies …

Cytotoxicity And Reproductive Impairment In Rainbow Trout Cell Lines Exposed To Microcystis Aeruginosa Extracellular Metabolites, Keira Harshaw

Electronic Theses and Dissertations

Current trends in cyanobacterial harmful algal blooms (cHABs) demonstrate increasing risks to human health and the health of aquatic ecosystems around the globe. Expansion of algal blooms, both geographically and temporally, serve to place increasing numbers of freshwater species, including fish, in peril. Microcystis aeruginosa, one of the most common species of bloom-causing cyanobacteria, is capable of producing a vast diversity of biologically active compounds, however Microcystis studies are often dominated by microcystins. How non-microcystin metabolites contribute to Microcystis toxicity, particularly in freshwater fish, has been the subject of a limited, but growing, body of research. To contribute to …

Consequences Of Environmental Manipulation On Behavioural And Neuromorphological Plasticity As It Relates To The Reintroduction Of Atlantic Salmon (Salmo Salar) To Lake Ontario, Ali I. Mokdad

Electronic Theses and Dissertations

The reintroduction of imperilled species has become an important tool in conservation biology and relies on the captive-rearing of remaining individuals, or a subset thereof, as a lifeline to prevent extinction. The success of reintroduction efforts has generally been low, mainly due to poor post-release performance of captive-reared animals. Captive-breeding programs tend to produce behaviourally and neurologically compromised animals that deviate from wild phenotypes and are less fit in natural settings. While genetic adaptation can account for some of the behavioural deficiencies expressed by captive-reared animals, phenotypic plasticity has been shown to play a large role. Phenotypic plasticity is generally …