Pop quiz: Can you figure out which of these photos is of Casco Bay?
The correct answer is B—but on any given day or part of the Bay, Casco Bay could look like any of these three pictures.
Why does it matter? Water color can be an important indicator of the environmental health of our waters.
For example, the bluish-green water from Casco Bay in the middle photo above was measured as 6 on the Forel-Ule scale. This tells us that the water color is dominated by phytoplankton, but also that some dissolved matter and some sediment may be present, which is typical for areas towards the open sea.
Image A is of water in the Caribbean and is a 2 on the scale—indigo blue with high light penetration. These waters have often low nutrient levels and low production of biomass.
Image C is from Lake Michigan and is a 18 on the scale. Brownish green to cola brown colors indicate waters with an extremely high concentrations of organic and inorganic compounds, which are typical for rivers and estuaries.
You and Friends of Casco Bay have joined a worldwide effort to better understand how our waters may be changing—by observing water color. The images above are photos taken by volunteers like you and have become part of a worldwide catalog of water color.
Since we launched our Color by Numbers pilot project using the EyeOnWater app three months ago, 178 people have signed up to measure the color of Casco Bay. The map of Casco Bay below shows where volunteers have taken 387 color measurements on their smartphones and tablets.
You are helping us learn more about the environmental health of Casco Bay. The data you collect, using the EyeOnWater app on your smartphone, will become part of a worldwide catalog of water color. The more measurements collected, the more our understanding of the Bay improves.
We look forward to keeping you posted about what we are learning.
For even more about the effort, see:
News Center Maine’s story about Color by Numbers: https://www.newscentermaine. com/article/news/local/this- app-is-changing-the-way- mainers-can-detect-water- pollution/97-581638282/
Maine Public’s coverage: http://www. mainepublic.org/post/ smartphone-app-s-helping- beachgoers-help-casco-bay# stream/0