Christine M. Hladik

Detecting the spatial and temporal variability of chlorophyll-a concentration and total suspended solids in Apalachicola Bay, Florida using MODIS imagery

Apalachicola Bay, Florida, accounts for 90% of Floridas and 10% of the nations eastern oyster (Crassostrea virginica) harvesting. Chlorophyll-a concentration and total suspended solids (TSS) are two important water quality variables, among other environmental factors such as salinity, for eastern oyster production in Apalachicola Bay. In this research, we developed regression models of the relationships between the reflectance of the Moderate-Resolution Imaging Spectroradiometer (MODIS) Terra 250 m data and the two water quality variables based on the Bay-wide field data collected during 14–17 October 2002, a relatively dry period, and 3–5 April 2006, a relatively wet period, respectively. Then we selected the best regression models (highest coefficient of determination, R 2) to derive Bay-wide maps of chlorophyll-a concentration and TSS for the two periods. The MODIS-derived maps revealed large spatial and temporal variations in chlorophyll-a concentration and TSS across the entire Apalachicola Bay.

Mapping phytoplankton chlorophyll in turbid, Case 2 estuarine and coastal waters

We tested variants of semianalytic algorithms for estimating phytoplankton chlorophyll pigment in Case 2 waters. Since 2002 we sampled 279 stations in 22 estuaries, bays, and near shore at seven National Estuarine Research Reserves between Delaware and Texas (USA). The following median values and ranges were observed: chlorophyll a = 17.4 μg/L3 (0.2-490.1); total suspended solids = 23.4 mg/L dry weight (0.7-191.1); and CDOM absorbance (440 nm) = 3.11 m-1 (0.00-21.08). Spectroradiometers measured volume reflectance at each station. Sampling was designed to capture upriver to coastal mixing gradients. Algorithms utilized features in the red and lower NIR, with interference adjustments for CDOM absorption and non-algal particle scatter using bands in either the green (550 nm) or NIR between 723-739 nm. Data from an additional 53 inland lake, reservoir, and river stations were included for comparison in algorithm testing. Our best two algorithms were re-parameterized using matchups with AISA Eagle imagery. Ex...