Bay Question

Type: Chesapeake
Region:
Location: The Bay

I have a question I was hoping you could help answer. I live in the upper bay near the Key Bridge and I�ve long been curious what causes the brownish/dirty look of our waters? Pollution, sediments, tides, bacteria? I couldn�t seem to find any definitive information on the subject. I would think that the amount of fresh water in the bay would create clearer conditions. What causes our water to appear so dirty versus waters in other areas of the world such as the Caribbean that are so crystal clear?

DNR Response: What causes differences in the color of ocean and coastal waters? The answer lies mainly in the absorption and scattering of light and the particles in the water. Larger volumes of particle-free water effectively absorb longer wavelengths of light like reds and greens, but scatter the shorter wavelengths of blue. In coastal waters like the Chesapeake Bay, however, the water is often teeming with particles like sediment and organic matter which can turn the water brown, or blooms of algae which can color the waters green or even shades of red. The crystal blue waters of the near shore Caribbean are created because there are generally less algae and particles in the water, allowing the blue hues to be seen. For more information, NASA has an excellent review of ocean color science. For information on Maryland's Chesapeake and Coastal Bay water quality visit DNR's Eyes on the Bay website.