Undeniably, water is not only a prime but also a precious natural asset and one of the key constituents of an ecosystem. It is used to meet various needs among them hydration, irrigation, livestock production, hydropower generation, and industrial production among other activities. Water is found in various sources among them streams, rivers, lakes, rainwater, glaciers, and groundwater. These sources, together with the species they support, form the backbone of aquatic ecosystems. However, with the increased human activities, the nature of these ecosystems has been a major source of concern lately.
Stressing events that are, to a larger extent, caused by human-induced contamination and pollution have led to a rapidly increasing deterioration of the quality of water in various sources. Similarly, aquatic ecosystems are continually experiencing loss of species and populations thereby threatening their general biodiversity (Doi et al. 1). As is evident, both the factors of water quality and biodiversity are demonstrating similar trends. It is important to understand whether the similarity in trends is an independent phenomenon or a consequence of the two factors having an impact on each other. Understanding how the two relate with each other can help in the formulation of policies aimed at enhancing the quality of the aquatic ecosystem and conserving biodiversity.
Several studies have been conducted to explore how both water quality and biodiversity affect each other as well as their combined effect on aquatic ecosystems. Understanding the role of each factor in the ecosystem has significantly helped in uncovering their respective influences in the ecosystem. Traditionally, biodiversity has been treated as an epiphenomenon of the chemical and physical variation that fosters diversification and enables species to exist together in harmony (Cardinale et al. 572). With regard to water quality, this view can be held to mean that biodiversity is just a secondary factor occurring simultaneously with water quality but not directly related to it. However, there have been several sentiments terming this unidirectional view as an incomplete representation of biodiversity. Various paradigms in fields such as those of paleontology, evolution, and ecology have continually shown that biodiversity is not just a product of the abiotic/ aquatic ecosystem, but rather, a major contributor to the formation of habitats (Cardinale et al. 572). This means that biodiversity has a significant impact on the formation of water sources and, by extension, the quality of water in those sources.
The relationship of biodiversity and water quality in terms of the influence of biodiversity on water quality has been explored, though not extensively. In a study to examine nutrient loading as a major contributor to water pollution, (Cardinale) found a significant relationship between biodiversity and water quality. Biodiversity was, for one, found to enhance the quality of water in streams by helping in the removal of excess nutrients in that are known to degrade the quality of water. This is made possible by division of labor and/ or niche partitioning. The rationale of this approach was that as the number of algae species in a stream increase, their geographical distribution within the stream expand, meaning they are spread across more water and can thus be cleansed through a pollution-removal process common to algae (Cardinale 87). Historically, the cleansing power of biodiversity has been acknowledged with scientists showing the greater capacity of ecosystems with more species diversity to remove pollutants from both water and soil. However, despite the study having a reliable design, it is also subject to the caveats of lab studies and its results should thus not be presumed to work in natural ecosystems (Gewin). Nevertheless, the study presents distinct implications for biodiversity conservation.
The impact of water quality on biodiversity has also been shown in various studies. Hari et al. demonstrated the impact of climatic change on water quality and the subsequent effect on biodiversity. The study found climate change to affect the water quality in terms of its temperature, which, in turn, affected brown trout populations in Alpine rivers and streams negatively (24). According to (Solheim et al. 40), the quality of water is affected by factors such as increased temperature stress, increased erosion, and changes in river flow. This factors, in turn, lead to the reduction of cold-water species, loss of various fish species, and an ultimate loss of biodiversity. A study by Mohamed, et al. also found water quality and biodiversity to have a significant relationship. However, a study by Paul and Goonan had different results where it showed that salinity, a common indicator of bad water quality, is not necessarily bad for biodiversity.
As is evident from the literature, a gap remains insofar as the relationship between water quality and biodiversity is concerned. Further investigation of the construct will help in closing the gap and also provide several implications for biodiversity conservation. In doing so, the study will be guided by the following research question:
RQ: What is the nature of the relationship between water quality and biodiversity in an ecosystem?
The following hypotheses will guide the evaluation of this question:
H1: More biodiversity improves the quality of water
H2: Good water quality enhances biodiversity
H3: The relationship between water diversity and biodiversity in an ecosystem is significant
Data will be collected from different water sources with the main variables being water quality and biodiversity. Two regression analyses will be performed with the first having water quality as the independent variable and the second having biodiversity as the independent variable. The first analysis will help in showing the effect of water quality on biodiversity while the second will show the effect of biodiversity on water quality. Indices to use in biodiversity analysis include Species richness, Shannon index, and Simpson Index. Water quality will be determined by salinity, conductivity, pH, and temperature indices. A t-test will help in showing the differences between the averages of water quality and biodiversity indices for distinct water sources thus helping in knowing whether the research results can apply to other ecosystems. The p-values of the regression models will help in showing the statistical significance of the relationship between water quality and biodiversity.
- Cardinale, B. J., et al. “The functional role of producer diversity in ecosystems.” American Journal of Botany, vol. 98, no. 3, 2011, pp. 572-592.
- Cardinale, Bradley J. “Biodiversity improves water quality through niche partitioning.” Nature, vol. 472, no. 7341, 2011, pp. 86-89.
- Doi, Hideyuki, et al. “Effects of biodiversity, habitat structure, and water quality on recreational use of rivers.” Ecosphere, vol. 4, no. 8, 2013, p. art102.
- Gewin, Virginia. “Algae biodiversity cleans streams.” Nature. International Weekly Journal of Science, 2011.
- Hari, Renata E., et al. “Consequences of climatic change for water temperature and brown trout populations in Alpine rivers and streams.” Global Change Biology, vol. 12, no. 1, 2006, pp. 10-26.