Modelling of nearshore microbial water quality at confluence of a local tributary in Lake St. Clair

Microbial water quality, measured as Escherichia coli (E. coli) concentration, at beaches along the southern shore of Lake St. Clair in Canada, often exceeds public safety guidelines. Belle River, located near a public beach and a drinking water intake, is one of the several smaller tributaries of the lake whose contribution to nearshore microbial water quality is currently unknown. A flexible mesh 3D coupled TUFLOW-FV and Aquatic Ecodynamic (AED2+) model was used to simulate the hydrodynamics and microbial water quality in Lake St. Clair. A higher resolution nested model was developed within the lake-wide TUFLOW-FV model for better spatial and temporal resolution in the local region surrounding Belle River. Regular and up to a factor of four difference in predicted E. coli concentrations were observed with the nested and lake-wide models at the public beach next to Belle River, whereas the difference was marginal at the drinking water intake about a kilometre away from the shore. While the E. coli loading to Lake St. Clair from Belle River is considered negligible, >90% of the predicted daily E. coli concentration at the beach and > 50 % at the water intake were attributed to Belle River from amongst all watershed sources to Lake St. Clair considered in the model. The model results also show that the construction of a new 150 m jetty in 2018, replacing the older 25 m jetty separating Belle River from the public beach, is expected to significantly reduce E. coli concentrations observed at the beach.     

An exploration of Lake Ontario’s offshore epibenthic cladoceran community

Pelagic cladocerans are relatively well studied within the Great Lakes. However, little is known about cladocerans that more closely interact with benthic substrate. In 2018, 26 sites in Lake Ontario were sampled with benthic grabs to collect meiofauna. The stations ranged in depth from 0.1 to 184 m with sand, silt or hard bottom substrate. Epibenthic cladocerans were recovered from all 12 sites shallower than 20 m, five of eight sites between 20 and 40 m and one (63 m deep) of six sites deeper than 40 m. The density of epibenthic cladocerans were at most 12% of the density of harpacticoid copepods (shallow hard bottom sites). The Lake Ontario epibenthic cladoceran community was represented by 16 species from 8 different genera although one of these species, Illyocryptus cf. sordidus, is likely represented by two cryptic species. The most widespread species was identified as Alona sibirica (Sinev, 2020), a newly described species from Russia formerly of the Alona cf. affinis (Leydig, 1860) species complex. The Great Lakes specimens were 98.3% similar genetically to sequences assigned to A. cf. sibirica. Among substrates, sand had the highest densities (1662 m² in 0–20 m) and species richness (10) of epibenthic Cladocera. After cladocerans were identified, the cytochrome oxidase I (COI) gene of 37 specimens were successfully sequenced through the Barcode of Life (BOLD). Six specimens were assigned to three previously existing Barcode Identification Numbers (BINs), the remaining 31 specimens were assigned to eight new BINs.     

Characterizing stream planform geometry using a novel application of spectral analysis

Quantifying the curvature in stream planform geometries traditionally uses discrete analysis methods to calculate sinuosity or channel index. The challenge with discrete methods is in selecting the appropriate length of channel to use as a window size in the calculations. In this study, a new methodology was introduced to guide and optimize window size selection with comparisons to more traditional methods. Channel index was the metric used in this study, defined as the ratio of stream length to straight line distance. Three methods were used to calculate channel index: classical method using total stream length, modified classical method using infrastructure-defined segments for window size, and a novel critical point method using continuous channel index spectra to determine window size. As a case study, each method was applied to an agriculturally dominant watershed in southwestern Ontario at Parkhill Creek to compare planform geometry changes between 1954 and 2015. This creek is historically known to have been straightened artificially for agricultural purposes. The novel critical point method was the best of the three, providing the best spatial resolution while generating optimized window sizes to calculate channel index for each individual tributary as well as the main creek channel. Using the critical point method, the creek was determined to be, on average, 23% straighter in 2015 than in 1954. The results of this study demonstrate the advantages of the novel critical point method in analyzing stream planform geometries and can be adapted for research in other streams.     

Proliferation of phytoplankton along a 500 km transect of the St. Lawrence River from its outflow at Lake Ontario

Observation of phytoplankton and water chemistry along the main channel of the St. Lawrence River was made at a high spatial resolution (every 12 km) in order to infer the factors that influence development of this phytoplankton community. The phytoplankton community in the main channel was collected over a 10-d period (mid July 2018) from the headwaters to near the beginning of the St. Lawrence River estuary. Total phosphorus concentration in river water increased with distance downstream (154–2,750 nM) and phytoplankton biomass (1.4–10.5 µg chl-a/L) was strongly correlated (r = 0.84, 46 d.f.) to the concentration of total phosphorus. Diatoms, chrysophytes and dinoflagellates dominated the phytoplankton community at the outlet of Lake Ontario and total chlorophyll-a concentrations increased three-fold with 500 km transit downstream from Lake Ontario; phycocyanin-rich Cyanobacteria showed the greatest proportional increase (227%). Total P concentrations observed in 1997 along this transect were identical to those observed in 2018; however, chl-a concentrations were much lower in 1997, a finding attributed to a greater filter feeding benthic organism impact on the standing crop of phytoplankton. Observations support the hypothesis that the phytoplankton community composition in this large river is strongly influenced by the headwater characteristics (Lake Ontario) and gradually influenced by entrainment of nutrient-rich tributary waters.     

PLA/algae composites: Morphology and mechanical properties

Bio-composites with poly(lactic) acid as matrix and various algae (red, brown and green) as filler were prepared via melt mixing. Algae initial size (below 50 μm and between 200 and 400 μm) and concentration (from 2 to 40 wt%) were varied. First, algae morphology, composition and surface properties are analysed for each algae type. Second, an example of algae particle size decrease during processing is given. Finally, tensile properties of composites are analysed. The surface of algae flakes was covered with inorganic salts affecting filler–matrix interactions. The Young’s modulus of composites increased at 40 wt% load of algae as compared with neat PLA although the strain at break and tensile strength decreased. In most cases the influence of algae type was minor. Larger flakes led to better mechanical properties compared to the smaller ones.     

Hedging Exposure to Volatile Retail Electricity Prices

In a deregulated setting, an approach dubbed the “get-out-of-jail card” offers customers the chance to engage in more selective and less expensive hedging activities than offered by conventional hedges.     

Selecting indicators to assess the fisheries of Lake Malawi and Lake Malombe: Knowledge base and evaluative capacity

The provision of management information on the fisheries of Lakes Malawi and Malombe has been characterised by top–down controlled single species steady-state assessment techniques originating from single gear industrial fisheries but applied to an open access highly diverse and adaptive small-scale multispecies and multi-gear fishery. The result has largely been an unhappy marriage with uncertainties blamed more on the data than the process, although the data collection generally is detailed and comprehensive on catch and effort parameters. An extensive literature review of primary and grey literature on ecosystem drivers, exploitation pressures, and fish population and community states shows that Malawi has the necessary knowledge base for expanding their assessment into multi-causal and exploratory indicator-based methods that can assist in better understanding and more disciplined use of existing data and monitoring systems. Selection and ranking of a suite of indicators focusing on the major fisheries in the Southeast arm of Lake Malawi and Lake Malombe were done by a group of Malawian fisheries researchers and management advisers, thereby testing a framework of scoring criteria assessing an indicator's acceptability, observability, and relatedness to management. Indicators that are close to raw observational data and that require limited permutations and few assumptions appear to be preferable in the Malawian context. CPUE-based assessments can improve the utility of data and information in communicating developments and processes and evaluate fisheries management policies.     

Solvent-induced supramolecular isomers: Two dimensional coordination polymers constructed by Cu(II) and fluconazole

Two Cu(II)–fluconazole supramolecular isomers 1 and 2 formulated as (flu)₂Cu(SCN)₂ (flu = fluconazole) have been synthesized and structurally characterized by single crystal X-ray diffraction. Different solvent media lead to the different binding modes of anion SCN⁻ and the flexible C–C chain of fluconazole has been rotated in the two isomers. Complex 1 exhibits a two dimensional square grid-like layer and complex 2 exhibits a two dimensional framework with a parquet motif. Different H-bonds and stacking modes are observed in the two isomers. Complex 1 is nonemissive, whereas complex 2 exhibits photoluminescence property.