Remote Sensing Spatiotemporal Assessment of Nitrogen Concentrations in Tampa Bay, Florida due to a Drought

Abstract

A long-term low nitrogen to phosphorus (N:P) ratio in the Tampa Bay, Florida, estuary system suggests that nitrogen is more limiting than phosphorus. However, south Florida suffered from a drought around 2007, and the reduction in runoff flowing into the bay affected local ecosystem dynamics. This study presents a remote sensing study to retrieve spatiotemporal patterns of total nitrogen (TN) concentrations in Tampa Bay under drought impacts through the integration of Moderate Resolution Imaging Spectroradiometer (MODIS) images and a genetic programming (GP) model. Research findings show that the drought impact on TN in Tampa Bay is both a seasonal and yearly phenomenon. Without the presence of ocean water intrusion, the whole bay would show a relatively uniform TN distribution during the drought period until the flow input from rivers returned to normal. Based on yearly comparisons, temperature could be the limiting factor on the plankton growth in Tampa Bay. To further substantiate the credibility of a nutrient estimation algorithm, a k-means clustering analysis was conducted to demonstrate sea-bay-land interactions among ebbs, tides, and river discharges. The seasonal cluster distribution in 2007 is generally consistent with the conventional segments division of Tampa Bay.

Tampa Bay estuary: Monitoring long-term recovery through regional partnerships

“…Methods to remotely-sense water quality parameters, such as colored dissolved organic material (CDOM) (Le et al, 2013), nutrients (Chang et al, 2012(Chang et al, , 2013, chlorophylla (Le et al, 2013a,b,c) and other parameters (Hu et al, 2014), are now being developed in the region. These products may offer greater spatiotemporal coverage in determining the water quality state of the estuary over traditional in situ collection methods, ) - Table 2 Example of annual compliance assessment steps for a hypothetical bay segment in Tampa Bay.…”