Tenmile Lakes HAB Report 2012

Identification Information

Citation

Originator: Tenmile Lakes Basin Partnership and Jake Kann

Publish Date: 4-8-2013

Online Link: http://tlbp.presys.com/Tenmile_Lakes_2012_summary_report_final_4-8-13.pdf

BPA Project #:

Contact Information

Agency: Watershed Councils

Name: Richard Litts

Job Position: Monitoring Coordinator

Telephone: 541-759-2414

E-Mail Address: tlbp@presys.com

Description

Abstract: 2012 marks the first year for which public health monitoring was based on direct algal toxin measurements (as opposed to cell density of potentially toxigenic cyanobacteria) in Tenmile Lakes. Cell density values provided by LSSU used non-standard laboratory methods that appear to cause reported cell densities to be biased low relative to alternative laboratories. Thus, 2012 cell density results could not be compared to previous years. However, because toxin values were available for all samples this did not affect the ability to compare to public health thresholds. Initial exceedances of public health guideline values for drinking water began in late August at N16 and Davis Dock. However, these were for cylindrospermopsin, and as described above, the presence of this toxin is uncertain at this time, and further work would be required to confirm its presence. There was only one occurrence of microcystin exceeding the drinking water guideline level in 2012, with a value of 1.45 µg/L detected at Davis Dock on 9/4/2012. This is in contrast to previous years when both Microcystis and microcystin greatly exceeded both drinking water and recreational public health guidelines (e.g., see Table 2 above) Although localized blooms and blue-green algal scums were noted that clearly had the potential to exceed recreational guidelines, toxin concentrations remained relatively low. One possibility is that Coelosphaerium/Woronichinia may have replaced Microcystis as the dominant species during 2012. The presence of Coelosphaerium may also explain why levels of microcystin in 2011 were lower than expected based on the microcystin-cell density relationship for previous years (Kann 2012). Other explanations may include either environmental factors, genetic factors, or both leading to variable ratios of toxin produced per unit algal density (Kann 2012; Bozarth et al.). The previous laboratory appeared to not have distinguish between Microcystis and Coelosphaerium/Woronichinia.

Purpose: Harmful Algae Bloom assessment.

Time Period of Content: June 2012 - Oct 2012

Geographic Extent: Tenmile Lakes, OR

Status: Final

Use Constraints:

Format: PDF Document

Data Quality Information

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Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description: Field attribute information is available in the database table field descriptions.

Is a physical copy maintained for reference at Headquarters? Unknown