Title

Relationship between microbial communities and metal mobility in urban watersheds, eastern San Francisco Bay Area, CA

Poster Number

12

Lead Author Major

Environmental Science

Format

Poster Presentation

Faculty Mentor Name

Laura Rademacher

Faculty Mentor Department

Earth and Environmental Sciences

Abstract/Artist Statement

Urban watershed-reservoir systems in the eastern San Francisco Bay area were investigated to determine the relationship between microbial communities and metal pollutant mobility. Results indicate that microbes and redox conditions play an important role in metal solubility. Three sites were selected for this research: 1) Lake Aliso/Lion Creek, a watershed impacted by an abandoned sulfur mine; 2) San Lorenzo Creek Reservoir/San Lorenzo Creek, located adjacent to a major freeway in an urban area; and 3) Lake Anza/Wildcat Creek, a low human impact watershed. Corresponding water and surface sediment samples were collected from each reservoir and from the primary tributaries that discharge into each of these reservoirs during summer 2013. DNA was extracted from each water and sediment sample then the 16S gene was amplified by polymerase chain reactions (PCR) and sequenced to determine the microbial community composition. Samples were also analyzed for metal concentration using inductively coupled plasma mass spectrometry (ICP-MS) and for field parameters including dissolved oxygen, pH, conductivity, and temperature using a YSI multiprobe. Iron concentrations in Lake Aliso waters increase between the lake inlet and outlet, and an abundance of the bacterial genus Geobacter was found within the lake. This suggests that Geobacter bacteria may mobilize Fe within the lake. San Lorenzo Creek Reservoir displayed high concentrations of Arsenic, particularly at the outlet site, and the abundance of bacterial genus Desulfomicrobium found in the lake is likely responsible for this. Further microbial analysis and conclusions from this study may be useful in the mitigation of redox sensitive pollutants in watersheds with small reservoirs.

Location

DeRosa University Center, Ballroom

Start Date

25-4-2015 2:00 PM

End Date

25-4-2015 4:00 PM

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Apr 25th, 2:00 PM Apr 25th, 4:00 PM

Relationship between microbial communities and metal mobility in urban watersheds, eastern San Francisco Bay Area, CA

DeRosa University Center, Ballroom

Urban watershed-reservoir systems in the eastern San Francisco Bay area were investigated to determine the relationship between microbial communities and metal pollutant mobility. Results indicate that microbes and redox conditions play an important role in metal solubility. Three sites were selected for this research: 1) Lake Aliso/Lion Creek, a watershed impacted by an abandoned sulfur mine; 2) San Lorenzo Creek Reservoir/San Lorenzo Creek, located adjacent to a major freeway in an urban area; and 3) Lake Anza/Wildcat Creek, a low human impact watershed. Corresponding water and surface sediment samples were collected from each reservoir and from the primary tributaries that discharge into each of these reservoirs during summer 2013. DNA was extracted from each water and sediment sample then the 16S gene was amplified by polymerase chain reactions (PCR) and sequenced to determine the microbial community composition. Samples were also analyzed for metal concentration using inductively coupled plasma mass spectrometry (ICP-MS) and for field parameters including dissolved oxygen, pH, conductivity, and temperature using a YSI multiprobe. Iron concentrations in Lake Aliso waters increase between the lake inlet and outlet, and an abundance of the bacterial genus Geobacter was found within the lake. This suggests that Geobacter bacteria may mobilize Fe within the lake. San Lorenzo Creek Reservoir displayed high concentrations of Arsenic, particularly at the outlet site, and the abundance of bacterial genus Desulfomicrobium found in the lake is likely responsible for this. Further microbial analysis and conclusions from this study may be useful in the mitigation of redox sensitive pollutants in watersheds with small reservoirs.