Transcripts of G2013-020_Chesapeake_Flyover_youtube_hq

The Chesapeake Bay is the national treasure. It’s one of the most productive estuaries in the world. It’s the largest estuary in the United States and has the largest land area to water volume ratio of any estuary in the US. Which means what happens on the land greatly affects the conditions of the Chesapeake Bay. Landsat is a critical and invaluable tool for characterizing the landscape and characterizing it in terms of mapping impervious surface, mapping it over time. We have satellite imagery for the Chesapeake Bay that covers the entire 64,000 square miles of the Chesapeake Bay watershed. Unfortunately, the Chesapeake Bay and 90 percent of its title tributaries are impaired. They're impaired with poor water clarity and low dissolved oxygen, as a result of excess nutrients and sediment coming into the bay. Excess nitrogen and phosphorous and sediment that's draining off the land into the Bay is obscuring the clarity of the water. The nutrients are contributing to increased algal growth. And when those algae die at the bottom of the bay and decompose, they starve the bay of oxygen oxygen that living resources need to survive. The sources of those nutrients and sediments are fertilizers, both manure and chemical fertilizers, applied to farmland and applied to residential lawns. It's also from the exhaust from our cars and air pollution from power plants out in the Ohio Valley. Landsat imagery is critical for monitoring changes in impervious surfaces, monitoring changes in tree canopy and and then other ground cover like grasses and shrubs. We can use the satellite imagery to track consistently through time across six states how the condition of the landscape has changed and what it is like. The Landsat satellite is basically a camera in space, and in essence it's actually seven cameras, because it collects the reflection of the sun off the earth's surface in seven bands, seven kind of wavelengths. We use this information to characterize different features on the land such as trees or impervious cover because each one of these features reflects the sun in different wavelengths. We're able to take the information from the satellite and take what's basically a bunch of numbers and translate that into well these numbers correspond to trees and these other numbers correspond to impervious surfaces, and do that consistently across very large areas. Landsat is just invaluable in providing this baseline of observations for science about how human activities on the land affect water quality, affect wildlife habitat, affect air quality. Without it we wouldn't be able to really understand how sources of nutrients and sediment have changed and where they are in the Chesapeake Bay.