Evaluating macrophyte selection and germination protocols to enhance nutrient sequestration in engineered wetland models

Research examining contaminant sequestration using engineered wetlands has been conducted for many years but the implementation of sustainable, biodiverse strategies is still in its infancy. A major gap in knowledge still exists regarding the kinds of macrophytes to be selected, especially the inclusion of non-invasive native flora. There is a lack of information about macrophyte selection criteria and germination protocols. Thus, this study attempted to redress this dearth in knowledge. The first part of this thesis critically assessed a list of macrophytes provided by Environment Canada (1996) and created “selection criteria” for choosing specific macrophytes. Germination protocols were then compiled to determine and outline optimized germination protocols for these aquatic macrophytes. In the second part of this study, two different constructed wetlands models were designed for laboratory purposes (a “floating” constructed wetland model and a “stationary” constructed wetland model). Water samples were assed for biological impact and phosphorus concentration.

Evaluating macrophyte selection and germination protocols to enhance nutrient sequestration in engineered wetland models

Research examining contaminant sequestration using engineered wetlands has been conducted for many years but the implementation of sustainable, biodiverse strategies is still in its infancy. A major gap in knowledge still exists regarding the kinds of macrophytes to be selected, especially the inclusion of non-invasive native flora. There is a lack of information about macrophyte selection criteria and germination protocols. Thus, this study attempted to redress this dearth in knowledge. The first part of this thesis critically assessed a list of macrophytes provided by Environment Canada (1996) and created “selection criteria” for choosing specific macrophytes. Germination protocols were then compiled to determine and outline optimized germination protocols for these aquatic macrophytes. In the second part of this study, two different constructed wetlands models were designed for laboratory purposes (a “floating” constructed wetland model and a “stationary” constructed wetland model). Water samples were assed for biological impact and phosphorus concentration.

Flexibility in the critical period of nutrient sequestration in bumble bee queens

Bumble bee queens undergo a nutrient storage period prior to entering diapause wherein they sequester glycogen and lipids that are metabolized during overwintering. In the laboratory under optimal food availability conditions, the majority of nutrients are sequestered during the first few days of adulthood. However, if food resources are scarce during this narrow window of time, wild queen bumble bees might be limited in their ability to obtain adequate food resources for overwintering. Here we used a laboratory experiment to examine whether queen bumble bees exhibit flexibility in the timing of pre-overwintering nutrient sequestration, by limiting their access to either nectar (artificial) or pollen, the two primary foods for bumble bees, for varying periods of time. In response to these treatments, we quantified queen survival, changes in weight, and glycogen and lipids levels. We found evidence that queens are able to recuperate almost entirely from food resource limitation, with respect to nutrient storage, especially when it is experienced for shorter durations (up to 6 days). This study sheds light on how bumble bee queens are impacted by food resource availability at a critical life stage.