Watershed Symposium 2017

Deciphering Cyano-blooms Using Molecular Approaches in Utah Lake

Summary:
This abstract will present findings on our continuous monitoring of Utah Lake and tracking the diversity of Cyano Blooms with the help from Utah Division of Water Quality. .

Full Abstract:
Although there are several environmental problems associated with HABs, the presence of CyanoHABs is of particular importance because certain species of cyanoHABs produce cynotoxins which have direct health related negative implications. CyanoHABs cause serious environmental and economic losses. Shallow, eutrophic Utah Lake encountered an extreme algal bloom event in the summer of 2016. As for the summer of 2017, an algal bloom event was identified in one location at the lake, Provo Bay. Conventionally, microscopic identification is used as the main method for phytoplankton identification. However, microscopic counting methods are time-consuming and results given are in low resolution and can overlook smaller cyanobacteria. For example, light microscope techniques usually exclude the study of picocyanbacteria because of the lack of its morphological knowledge (Ouellette et al., 2005) and the small size of picocyanobateria (0.2 to 2.0 μm) (Jakubowska and Szeląg-Wasielewska, 2015). Morover, microscopic methods may not be able to differentiate between toxin-producing and non-toxin producing strains. For example, different strains of Microcystis aeruginosa can be morphologically identical but differ in toxigenicity (Otsuka et al., 1999). To overcome these problems, we have applied molecular methods for cyanobacterial speciation by sequencing all the bacterial DNA from water and sediment samples as well as targeting dominant species in Utah Lake by quantitive PCR. To establish the presence with their functionality, we have been also extracting mRNA and tracking gene expressions. Five sites were monitored in 2016 and cyanobacterial communities were genetically identified via high throughput amplicon sequencing. Similarly, seven sites were monitored in summer 2017. Sediments were collected in August of 2016 and August of 2017. Our findings for summer of 2016 show that temperature and chlorophyll a increased throughout. Nutrients and pH were the highest during the bloom. As for cyanobacteria identification via high throughput amplicon sequencing, Aphanizomenon flos-aquae and Synechocuccos sp (picocyanobacteria) dominated the water column. As for sediment cyanobacteria identification, Aphanizomenon flos-aquae dominated. Furthermore, sediments were dominated by Ca-bound phosphorus and sediment mineralogy contained around 70% calcite. As for summer of 2017 findings, pH, temperature and chlorophyll a increased significantly from early May to mid July. In Provo Bay where algal blooms appeared in 2017, nitrate was significantly reduced while the phosphate was high. Blooms faded towards the end of summer in Provo Bay. In addition, DNA was extracted for each site in 2017 for sequencing and cyanobacterial speciation analysis. Dominant gene expressions are detected by extracting mRNA. By analyzing our collected biological and chemcical data from both summers, we can get a better understanding of algal and cyanobacteria bloom occurences at Utah Lake and capable of determining ecosystem tipping point. Audience will be able to learn; (1) What is CyanoHABs and why they form, (2) what environmental factors trigger their formation, (3) what is the ecological diversity with seasonal changes and (4) how citizens can be involved in ongoing efforts to address water quality problems in Utah.