MODELING CHLOROPHYLL-A CONCENTRATIONS USING LANDSAT 8 SATELLITE IMAGERY

The Ohio River system supplies water to ~5 million people making its cleanliness essential. The frequency at which harmful algal blooms appear in the Ohio River is continuously increasing as a side effect of human activities. Harmful algal blooms should be monitored due to the negative effect that they have on human and ecosystem health. The major objective of this project is to develop an algorithm to calculate chlorophyll-a concentrations from satellite images. Four locations were sampled on two separate days (July 3^rd and October 6^th) near the Thomas More Biology Field Station. Two samples were taken upstream of the field station (OR1 and OR2) and two were taken downstream (OR3 and OR4) during each sampling period. Water quality parameters including geographic coordinates, salinity, pH, dissolved oxygen, nitrate concentration, chlorophyll and phycocyanin concentrations were measured using a YSI portable water quality monitoring sonde. The October sampling site yielded higher concentrations of chlorophyll-a (OR1 = 2.14 mg/l, OR2 = 2.20 mg/l, OR3 = 1.99 mg/l, OR4 = 2.49 mg/l, mean = 2.21 mg/l) while July samples yielded lower (OR1 = 2.36 mg/l, OR2 = 2.22 mg/l, OR3 = 2.01 mg/l, OR4 = 2.15 mg/l, mean = 2.19 mg/l). Sampling site location OR3 had the lowest chlorophyll-a concentrations indicating an area low in algal bloom productivity. Nitrate concentrations were higher in October (OR1 = 160.30 mV, OR2 = 164.10 mV, OR3 = 161.70 mV, OR4 = 161.90 mV, mean = 162 mV) than in July (OR1 = 177.70 mV, OR2 = 136 mV, OR3 = 179.40 mV, OR4 = 103.40 mV, mean = 149.125 mV) indicating a correlation to chlorophyll productivity. Chlorophyll-a measurements across both sampling periods indicate the Ohio river is an oligotrophic body of water. Separate algorithms will be developed to calculate the chlorophyll-a concentrations from LandSat 8 satellite imagery. LandSat 8 imagery will be extracted through Earth Explorer and will be analyzed using ArcMap. The desired results would provide chlorophyll-a measurements similar to those collected during field measurements. Calculated Chlorophyll-a concentrations will be compared to concentrations measured using YSI. Findings of the project can be used to efficiently monitor harmful algal blooms to improve drinking water quality.