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

Abstract

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.

The Continuation of Native Non-Invasive Plant Species Research of Engineered Wetlands

“…This thesis intends to focus on their ability to purify wastewater by phytoremediation. And to continue the work started by Tiley (2013) and Fernandes (2017).…”

“…The term "native species" refers to species that are naturally located in a geographical ecoregion without any introduction via human activities (Cronk & Fennessy, 2001;The National Wildlife Federation, 2019a). On the other hand, invasive species are non-native species that are intentionally or accidentally introduced to an area that they predominate by spreading rapidly (Cronk & Fennessy, 2001;Capotorto, 2006;Fernandes, 2017). However, some native species can possess invasive characteristics and become invasive when relocated to different sections of an area in which they reside (Tiley, 2013).…”

“…However, some native species can possess invasive characteristics and become invasive when relocated to different sections of an area in which they reside (Tiley, 2013). This occurrence can be explained by multiple hypotheses that suggest: i) resources previously devoted towards defense are now devoted to reproduction; ii) an increased mutualistic relationship between plant and soil microbes; iii) increased vulnerability of native species (Capotorto, 2006;Fernandes, 2017).…”

“…Despite its invasive nature nevertheless, Typha species such as Typha latifolia continue to be used in constructed wetlands for wastewater treatment because they are tolerant to various stressors such as pollution, inconsistent water levels and soil salinity (Havens et al, 1999;Coleman et al, 2001;Capotorto, 2006;Ijaz et al, 2016). Typha monoculture constructed wetlands can only be justified for closed systems that can not result in an outbreak that will impact the rest of the ecosystem (Fernandes, 2017). It is important to note that T. latifolia is not inherently invasive and is still considered an essential species, but evidence suggests that it has the ability to become invasive by aggressively displacing other native species and consequently, decreasing biodiversity (Tiley, 2013).…”

“…Once wetland plants were obtained, an in-lab engineered wetland system was developed by building upon past research and methodologies conducted by Tiley (2013) andFernandes (2017).…”