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Watershed Symposium 2018 has ended
Welcome to the official website of the 12th Annual Salt Lake County Watershed Symposium, November 14-15, 2018!  Free and open to all, the Symposium encourages a comprehensive review of the current state of our watershed while creating learning and networking opportunities for a broad array of stakeholders. Sessions cover a broad range of topics on water quality and watershed issues with local, regional, and national relevance.  Hosted annually by Salt Lake County Watershed Planning & Restoration.

Powerpoints and audio recordings are available!  Click on a session and scroll down to the attached files.
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Wednesday, November 14 • 3:20pm - 3:50pm
Phosphorous, Grazers, and Temperatures May Intensify Utah Lake HABs

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Phosphorous, Grazers, and Temperatures May Intensify Utah Lake HABs

Our results indicate that HAB contributors are triggered by more biologically available phosphorus and higher temperatures that stimulate Eukaryotic grazer populations. Further, we observed that the most dominant HAB species, Aphanizomenon, had no identifiable triggers but was so prolific that its growth ultimately curtailed its own bloom.

Full Abstract
The inception and persistence of harmful algal blooms (HABs) is linked to the appropriate conditions for a given cyanobacteria to break dormancy and become abundant. Certain cyanobacterial species may exploit natural and anthropogenic nutrients, such as phosphorus (P) and nitrogen (N), thrive under seasonal fluctuations in meteorological and physicochemical lake conditions, and/or escape predation of eukaryotic grazers to grow and potentially produce cyanotoxins. To identify specific environmental cues or conditions promoting individual HAB species, we tracked shifts in abundance of major cyanobacterial species in response to fluctuations in nutrient availability, top-down grazer pressure, and atmospheric and lake chemistry weekly through the spring and summer (May 5th – Oct 10th) of 2017 across three locations (mouth of Goshen Bay and Provo Bay, and 1 mile west of Vineyard) in Utah Lake, UT, USA. We found that 11 cyanobacterial operational taxonomic units or species across five genera (Aphanizomenon, Anabaena, Synechococcus, Microcystis, Planktothrix) contributed to three to six HABs, depending on location, constituting anywhere from 4% to almost 50% of the total bacterial community in surface waters. Based on linear mixed effects models, HAB contributors were triggered by species-specific interactions with light availability, total P (TP), total dissolved P (TDP), soluble reactive P (SRP), water temperature, and three grazers (Genus: Copepoda, Cyclopoida, and Diplostraca). For example, Synechococcus sp., a microcystin-producing picoplankton, which was only second in abundance to Aphanizomenon in HABs, was positively related to SRP and temperature (R2=0.35, F value=13, p-value<0.001). A HAB species of global concern and non-heterocystous former, Microcystis, was negatively related to total P (TP), but positively related to total dissolve P (TDP) demonstrating that the movement of P between occluded and available forms may structure its blooms (R2=0.18, F value=5.3, p-value=0.008). Similarly, Planktothrix, was also positively related to more available forms of P, SRP, and its growth potentially stimulated Copepoda grazing (R2=0.35, F value=5.7, p-value=0.003). Alternatively, Aphanizomenon sp., the most abundant bloom species, was negatively related to higher light penetration and positively related to total organic carbon (C) and Cyclopoida grazers, suggesting that Aphanizomenon altered physical, nutrient, and grazer characteristics; was insensitive to lake conditions; and potentially created a negative feedback causing its bloom to decline (R2=0.31, F value=4.8, p-value=0.007). Our results indicate that HAB contributors are triggered by more biologically available phosphorus and higher temperatures that stimulate eukaryotic grazer populations. Further, we observed that the most dominant HAB species, Aphanizomenon, had no identifiable triggers but was so prolific that its growth ultimately curtailed its own bloom.

Speakers
SC

Scott Collins

Research Student, BYU
Scott Collins is from Manassas, Virginia. He completed his undergrad at BYU in Environmental Science with minors in Business and Italian. He is currently pursuing a Master's degree in Environmental Science at BYU. After finishing his Master's degree he will pursue a career in Water... Read More →
avatar for Erin Jones

Erin Jones

Graduate Researcher, Brigham Young University
Erin is a PhD candidate at BYU in environmental sciences. Her research interests include aquatic microbial ecology, limnology, urban water quality, science education, and public outreach.



Wednesday November 14, 2018 3:20pm - 3:50pm
Lower Level - Ballroom C Utah Cultural Celebration Center, 1355 W 3100 S, West Valley City, UT 84119

Attendees (8)