The Effect of Combined pH and Sediment Levels on Chlorella vulgaris Growth, to Replicate Various Water Conditions In South Carolina

Josie Gardiner

School Name

Spring Valley High School

Grade Level

11th Grade

Presentation Topic

Environmental Science

Presentation Type

Non-Mentored

Abstract

Microalgaes such as Chlorella vulgaris are often cultivated commercially to produce biofuel. One setback of microalgae cultivation is having a cost efficient water source that contains the necessary conditions for optimal algal growth. Therefore, the purpose of this experiment was to locate a water source in South Carolina that could be used to supply nearby algae farms. It was hypothesized that the Lake Marion group would yield the highest absorbance. To conduct this experiment, lakewater from Lake Carolina, Marion, and Hartwell was tested for pH and sediment levels. These conditions were then replicated in the lab to cultivate Chlorella vulgaris. Lake Carolina had a pH of 5 and 3 g/L SiO2, Hartwell had a pH of 6 and 0 g/L SiO2, Marion had a pH of 6 and 1.5 g/L SiO2, and the control had a pH of 7 with no sediment. A spectrophotometer was used to measure light absorbance, which correlates to cell density. It was found that the Lake Carolina group had the highest average absorbance of 1.8659, and therefore the highest relative cell density. An ANOVA and Tukey test were ran, which determined that the Lake Carolina group was significantly higher than the Lake Hartwell and Lake Marion groups. This suggests that Chlorella vulgaris grows better in water from Lake Carolina, compared to Lake Hartwell and Marion. These results are likely due to higher sediment levels in Lake Carolina, rather than its pH, since Chlorella does not typically thrive in acidic pH.

Location

Furman Hall 229

Start Date

3-28-2020 9:45 AM

Presentation Format

Oral and Written

Group Project

No

COinS
 
Mar 28th, 9:45 AM

The Effect of Combined pH and Sediment Levels on Chlorella vulgaris Growth, to Replicate Various Water Conditions In South Carolina

Furman Hall 229

Microalgaes such as Chlorella vulgaris are often cultivated commercially to produce biofuel. One setback of microalgae cultivation is having a cost efficient water source that contains the necessary conditions for optimal algal growth. Therefore, the purpose of this experiment was to locate a water source in South Carolina that could be used to supply nearby algae farms. It was hypothesized that the Lake Marion group would yield the highest absorbance. To conduct this experiment, lakewater from Lake Carolina, Marion, and Hartwell was tested for pH and sediment levels. These conditions were then replicated in the lab to cultivate Chlorella vulgaris. Lake Carolina had a pH of 5 and 3 g/L SiO2, Hartwell had a pH of 6 and 0 g/L SiO2, Marion had a pH of 6 and 1.5 g/L SiO2, and the control had a pH of 7 with no sediment. A spectrophotometer was used to measure light absorbance, which correlates to cell density. It was found that the Lake Carolina group had the highest average absorbance of 1.8659, and therefore the highest relative cell density. An ANOVA and Tukey test were ran, which determined that the Lake Carolina group was significantly higher than the Lake Hartwell and Lake Marion groups. This suggests that Chlorella vulgaris grows better in water from Lake Carolina, compared to Lake Hartwell and Marion. These results are likely due to higher sediment levels in Lake Carolina, rather than its pH, since Chlorella does not typically thrive in acidic pH.