Award Date

5-1-2014

Degree Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

Health Sciences

First Committee Member

Shawn Gerstenberger

Second Committee Member

Steve Weber

Third Committee Member

Jeff Janik

Fourth Committee Member

Penny Amy

Number of Pages

82

Abstract

The water chemistry of Lake Las Vegas (LLV), a Southern Nevada man-made reservoir, is influenced by both anthropogenic and natural sources. These sources affect the reservoir's water chemistry, which may promote harmful algal blooms (HABs) leading to massive fish kill events. Fish kills, caused by the golden algaePrymnesium parvum (P. parvum), continue to pose a threat in the reservoir. However, no effective treatments to controlP. parvumin large reservoirs such as LLV have been determined. This cross-sectional study evaluated important variables that may affectP. parvumHABs in LLV, including non-P. parvumbiomass (mg/m3), total zooplankton abundance (#/m3), temperature, TDS (salinity), mineral concentration (Ca, Mg, K, Na), total nitrogen (TN), total phosphorous (TP), and N:P ratios. Using secondary analysis from Water Quality Monitoring Reports, mid-month data was collected from December 2009 through December 2012 (N=38). This time frame was selected due to an algal bloom occurrence in December 2009, which led to the first fish kill event approximately thirty days thereafter. Univariate and multivariate regression analysis were performed using a 30 day lag in order to traverse appropriate date ranges to determine variable significance for hypotheses testing. Statistical analyses found temperature, TDS (salinity), mineral concentration (Ca, Mg, K, Na), and TN to be significant predictor variables (p≤0.1) forP. parvumbloom formation. Observational analysis of interactions between independent variables onP. parvumbloom formation was also assessed, which may be key to making profound research discoveries. This study supports the findings in the literature; however, becauseP. parvumblooms in LLV are unique compared to other strains, different treatments for mitigation may be needed. Further studies are needed to elucidate the mechanisms of golden algae biosynthesis, its biology and ecology, as well as its associated toxicity, in order to better manage blooms leading to fish kill events in LLV.

Keywords

Algal blooms—Control; Fish kills; Prymnesium parvum; Water chemistry

Disciplines

Environmental Sciences | Natural Resources Management and Policy | Terrestrial and Aquatic Ecology

Language

English


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