Home » The Bay Is Blooming

The Bay Is Blooming

What are the signs of spring for you? Chirping chickadees? Street sweeping? Longer daylight? Changing the clocks? (March 8th is the start of Daylight Savings Time!)

The lengthening daylight jumpstarts the growth of phytoplankton, the single-celled plants that are the foundation of the ocean food web. Like plants on land, they respond to increasing sunlight by bursting into bloom.

The graph of chlorophyll fluorescence shows the increase and decrease in phytoplankton abundance in Casco Bay throughout the year at our Continuous Monitoring Station in Yarmouth.

How can we know what is happening in the ocean? Our Continuous Monitoring Station indicates the abundance of phytoplankton in Casco Bay by measuring chlorophyll fluorescence. Chlorophyll is the green pigment in plants that traps the energy of the sun for photosynthesis.

Our long-term monitoring station, anchored just above the sea floor off Cousins Island in Yarmouth, collects measurements of temperature, salinity, pH, dissolved oxygen, carbon dioxide, and chlorophyll fluorescence, every hour, year-round.

Staff Scientist Mike Doan observes, “Our Continuous Monitoring Station is going into its fifth year of data collection. During the first two springs [2017 and 2018], the chlorophyll levels peaked, as expected, around March, which would be consistent with seasonal phytoplankton bloom cycles. Last year, we experienced a winter bloom that peaked in January, much earlier than we would have expected. So far this winter we have experienced a similar situation, with a moderate bloom over the winter. We are very interested in seeing what the February and March data tell us.”

We update our website each month, so come back often to see if these early blooms continue to occur in Casco Bay, yet another signal that things may be changing in the Bay.