Our Continuous Monitoring Station has been collecting hourly data on the health of the Bay for more than four years.
Data from the station show that this summer has been the hottest one we have recorded since our “Cage of Science” has been in the water.
This graph compares water temperatures from 2016 to this month. The lavender-colored line represents the daily averages for this year.
Staff Scientist Mike Doan says “The data are concerning. This summer’s temperatures were on average the warmest we have seen at the station.”
You can find the most recent data for all the parameters we measure at our Cage of Science here.
In addition to collecting hourly data, for nearly 30 years, we have been spot-checking sites in the Bay. The temperature data from our three Sentinel Sites (see graph below for annual average, data collected May through October each year) show an upward trend as temperatures in Casco Bay have risen by 2.4° Fahrenheit [1.3° Celsius].
“Casco Bay is changing and changing quickly,” reports Executive Director Cathy Ramsdell. “That’s why we have launched the Climate Change and Casco Bay Fund, which will help us put two more Continuous Monitoring Stations in the water, one near Portland and one near Harpswell, and operate all three stations for ten years.”
The $1.5 million Climate Change and Casco Bay Fund will be used over the next decade to understand the ways in which our waters are changing, while we engage the community in assessing and adapting to climate change. Friends of Casco Bay has raised 87% of its goal for the Fund. You can read more about the Fund, our 10-year plan, and make a secure donation here.
What is this Cage of Science that Friends of Casco Bay keeps talking about? We invite you to join Staff Scientist Mike Doan out on Casco Bay for a short tour of our Continuous Monitoring Station. In this 2 ½ minute video, Mike shows off the high-tech components of the station and shares why its stream of data is so important to our work.
If you have ever tried to pick the right shade of green to paint your bedroom, you know there are soothing greens and greens you would never want to wake up to. The same holds true in the ocean.
Algae is one of those “greens” that can be a sign of a healthy ecosystem; but large areas of mudflats may become covered in a nightmarish bright green when algal growth is fueled by too much nitrogen in the water.
In 2019, as the water warmed from spring through fall, volunteers in our Water Reporter observing network tracked algal blooms that appeared in 18 different locations around Casco Bay. The photos they took on their smartphones documented changes throughout the summer, as the algal blooms expanded to worrisome levels in many coves from Cape Elizabeth to Harpswell and West Bath.
In 2017, we tracked algal growth at five sites. We do not have enough historical data to know whether nuisance algal blooms are expanding or simply that we are getting better at tracking more sites, thanks to our growing network of Water Reporters.
In any case, nuisance and harmful algal blooms are an increasing concern. Water Reporters are already discovering and tracking sightings in 2020!
Community Engagement Coordinator Sarah Lyman oversees our Water Reporter program. This year, Sarah hopes to recruit additional volunteers to our band of intrepid Water Reporters who track algal blooms. “Each volunteer will adopt a specific Bay location to observe weekly. Images of algae from the ‘good’ amounts to ‘concerning’ amounts are helpful because we can’t predict where and when a small patch of algae may become a nuisance algal bloom.”
Currently, there are 205 volunteers in our Water Reporter network. Together, they have recorded 991 observations about Casco Bay. If you are interested, learn more at cascobay.org/water-reporter.
Nitrogen fertilizes the ocean, too
Nitrogen encourages the growth of plants on land and in the ocean, where it stimulates the growth of algae, from microscopic phytoplankton to sinuous seaweeds, the base of the ocean food web.
Excess nitrogen can stimulate algal growth beyond what marine life can absorb. Nuisance algal blooms can cover tidal flats with a thick carpet of “green slime,” smothering animals below the mat and preventing juvenile clams from settling into the mud. Large phytoplankton blooms can reduce water clarity. When these blooms die, decomposition sucks life-giving oxygen out of the seawater and releases carbon dioxide, creating acidic conditions that make it harder for clams and mussels to build and maintain their shells.
When we look at our water quality data, we can see that some characteristics of the Bay influence other characteristics. In this example, large phytoplankton blooms have a big impact on the chemistry of Casco Bay.
Ready for some Marine Science 101?
In the graph below, we compare two types of data we collect at our Continuous Monitoring Station: chlorophyll and pH.
We measure chlorophyll to understand how much phytoplankton is in the water. Phytoplankton are microscopic plants that are the base of the food chain. Chlorophyll is the green pigment in phytoplankton (and all plants) that traps the energy of the sun for photosynthesis. Higher levels of chlorophyll indicate an abundance of phytoplankton. Graphs of chlorophyll show when populations of phytoplankton are on the rise and when they crash.
pH is a measure of acidity. The lower the pH, the more acidic the solution. The pH measurement decreases as acidity increases. That is because pH is an inverse measure of the concentration of hydrogen ions in a solution, measured on a scale of 0 to 14. The scale is logarithmic, and each number is an order of magnitude different. For example, a pH of 7 is ten times more acidic than a pH of 8, and one hundred times more acidic than a pH of 9. pH is an abbreviation for “power of hydrogen.” Any solution with a pH lower than 7 has more hydrogen ions than hydroxide ions. Data from our Continuous Monitoring Station show that pH is around 8.0 on average, but changes hourly, daily, and seasonally.
What is this graph telling us?
The graph above compares chlorophyll and pH data from our station. The two lines track the daily means of that data calculated from July 2016 through mid-March 2020.
You can see the variability in both chlorophyll and pH over time, moving from left to right.
When chlorophyll spikes, there is generally an uptick in pH, and then a decrease in pH as chlorophyll levels drop.
Why does this happen?
Whenever carbon dioxide (CO2) is added to water, the water becomes more acidic (pH goes down). The opposite is true as well. Acidity decreases (pH goes up) as CO2 is removed from the water.
When phytoplankton photosynthesize, they convert carbon dioxide (CO2) from the water to carbohydrates and oxygen. This reduces the amount of CO2 in the water, lowering the acidity. The larger the bloom of phytoplankton, and the longer the daylight hours, the lower the acidity (and the higher the pH). Other factors influence pH as well, but the amount of phytoplankton is a primary driver.
As the bloom ends, much of the phytoplankton die and decompose. The process of decomposition releases CO2 to the water and pH levels go down (more acidic water).
Compare changes in chlorophyll and changes in acidity throughout the year here.
Living close to the ocean, Casco Bay residents are witnessing the effects of climate change happening here now: warming water temperatures, increasing ocean acidity, and more severe storms. We too are seeing the changes in our data and when we are out on the Bay.
From April through October, our Research Associate Mike Doan and Casco Baykeeper Ivy Frignoca are on the Bay frequently to monitor water quality, follow up on pollution reports, or meet with partners on issues best understood from the water. Their vigilance gives them a firsthand view of changes happening in our coastal waters.
Mike, Ivy, and Executive Director Cathy Ramsdell shared these and other observations in our first-ever Casco Bay Matters series. Nearly 400 people attended Ocean Acidification, Climate Change and You presentations about what we are learning about a changing Casco Bay.
They shared how Mainers are working together to shape policies and actions to respond to these threats. Ivy is coordinating the Maine Ocean and Coastal Acidification partnership, a diverse coalition of scientists, lawmakers, aquaculturalists, and seafood harvesters, who collaborate on research and strategies to confront the threats that climate change and acidification pose to Maine’s marine resources. We also are working with legislators to pass a bill to create a state-sponsored Science and Policy Advisory Council on the Impact of Climate Change on Maine’s Marine Species.
Video Recordings of Casco Bay Matters:
If you missed our Casco Bay Matters presentations of Ocean Acidification, Climate Change and You, you are in luck — our stalwart volunteer Deb Dawson recorded and edited videos of our South Portland (March 25, 2019) event. See the series of three videos on our YouTube channel.
Highlights from Casco Bay Matters:
Warmer waters: Friends of Casco Bay has been tracking water temperatures for over a quarter century. On average, water temperatures in Casco Bay have risen 2.5°F (1.4°C) since 1993. The growth, reproduction, and survival of marine life are influenced by temperature.
More carbon dioxide in our coastal waters from air and from land: We know that burning fossil fuels adds carbon dioxide to the atmosphere, trapping heat and warming the planet. Nearly 30% of atmospheric carbon dioxide is absorbed by the ocean. Carbon dioxide mixes with water to form carbonic acid, making the water more acidic. This is ocean acidification.
Maine’s nearshore waters are also at risk from coastal acidification. Excess nitrogen from sewage treatment plants, polluted stormwater, and fertilizers can stimulate massive algal growth. When the algal blooms die, decomposition depletes the area of lifegiving oxygen and releases carbon dioxide, further acidifying the water.
Threats to the ocean food web: More carbon dioxide in our waters means less shell-building material (calcium carbonate) for clams, mussels, and planktonic creatures that support the ocean food chain. Data from our Continuous Monitoring Station enable us to calculate the calcium carbonate saturation state — what scientists term omega aragonite — which can tell us whether, at any given time, enough calcium carbonate is readily available to shell-building creatures. Shell formation becomes more difficult for some species when the amount of available calcium carbonate falls below a 1.5 aragonite saturation state.
Sea level rise: As water warms, it expands, and the seas encroach on our coastline. Coastal observers and property owners are reporting more erosion.
Increasing precipitation: Maine has seen a six-inch rise in average annual precipitation since 1895, further threatening coastal properties. Torrential rains intensify erosion and flush overloads of nitrogen, pollutants, and sediments into coastal waters.
Those who depend upon the sea can attest to the fast pace of change. What do these changes mean for Casco Bay?
As oceans become more acidic, we can anticipate more pitting or thinning of the shells of many commercially viable species in Casco Bay, such as clams, mussels, and oysters.
Voracious green crabs — which eat juvenile shellfish — thrive in warming waters.
Rising water temperatures are linked with shell disease in crustaceans, directly impacting Maine’s iconic lobster fishery.
Scientists and lobstermen are documenting lobster populations shifting north and east.
Copepods, tiny crustaceans that are the main food source for juvenile lobsters, may not be as plump as they once were. In laboratory experiments that simulate climate changes now happening in the Gulf of Maine, copepods were less fatty. With a less nutritious diet, young lobsters must divert energy from growth and resisting disease to finding enough food to survive.
The climate is changing faster than expected. Greenhouse gases, such as carbon dioxide and methane, are the culprits. The burning of fossil fuels for homes, industry, and transportation releases almost 10,000 million metric tons of carbon dioxide into the atmosphere every year. 1
Carbon dioxide is changing not only our climate, but also the chemistry of the ocean. About 30% of the carbon dioxide we release into the atmosphere is absorbed by the ocean. 2 In marine water, carbon dioxide decreases pH and increases acidity through a process known as ocean acidification.
Excess nitrogen from sewage treatment plants, polluted stormwater, and fertilizers, is also adding carbon dioxide into nearshore waters through a process known as coastal acidification. 3
Nitrogen can fertilize massive algal growth in our waters. When the algal blooms die, decomposition depletes the area of life-giving oxygen and releases carbon dioxide, acidifying the water.
The impacts of climate change are evident right here in Casco Bay
Friends of Casco Bay has been tracking water temperatures for over 25 years. On average, our data show a 2.5° F increase in water temperatures since 1993.
Sea Level Rise
As water warms, it expands, and the sea encroaches on our coastline. Coastal observers and property owners are reporting an increase in erosion.
Maine has seen a six-inch average increase in annual precipitation since 1895, further threatening coastal properties. 4
Threats to the Ocean Food Web
More carbon dioxide in our waters means there is less shell-building material (calcium carbonate) for clams, mussels and oysters, as well as for tiny critters at the base of the ocean food chain. The saturation state of calcium carbonate is a key measurement of shell-building material for many organisms. Shell formation becomes more difficult when the amount of available calcium carbonate falls below a 1.5 saturation state. 5 Our recent data indicate that for nearly half the year, levels of calcium carbonate in Casco Bay are not sufficient for shell-building.
What do these changes mean for Casco Bay?
As marine waters become more acidic, we can anticipate more pitting or dissolution of the shells of many commercially viable species in Casco Bay.
Rising water temperatures are linked with shell disease, directly impacting our lobster fishery and tourism industries.
Climate change is bad news for clams because green crabs — which eat juvenile shellfish — thrive in warming waters. 6
The distribution and populations of marine species in the Gulf of Maine are shifting. Scientists and lobstermen are documenting the shift in distribution of Maine’s iconic lobsters north and east.
Copepods are tiny crustaceans that are the main food source for juvenile lobsters. In laboratory experiments, copepods raised in conditions that simulate the climate changes occurring in the Gulf of Maine were less fatty. With a less healthful diet, young lobsters must divert energy from growth and resisting disease to finding enough food to survive. 7
What is Friends of Casco Bay doing?
We helped form the Maine Ocean and Coastal Acidification Partnership (MOCA) to coordinate climate change research and policy change work. MOCA is a diverse coalition of researchers, policy experts, lawmakers, aquaculturalists, and seafood harvesters. We are working to create an action plan for Maine to protect the health of our coastal waters.
LD 1284 has been selected by the Environmental Priorities Coalition, a group of 34 environmental organizations, as one of its five priority bills to address climate change in Maine.
Our Water Reporter volunteers are recording observations of how the Bay is changing. These observations strengthen our advocacy efforts as these reports are shared with regulators, legislators, and other decision makers, alerting them to conditions in the Bay.
What can you do?
Tell your legislators to support LD 1284 to create a science and policy advisory council to address the impacts of climate change on Maine’s marine species.
On July 20, 2016, our Continuous Monitoring Station began recording data hourly, 365 days a year. We are excited to share the first two and half years of data, collected at our water quality monitoring site in Yarmouth, near the coastal midpoint of Casco Bay. We will update these graphs monthly, so come back often and see for yourself how Casco Bay is changing.
You may know that Friends of Casco Bay’s Continuous Monitoring Station—AKA our “Cage of Science”—gives us vital data about the health of the Bay. But did you also know that observations of what sea life is growing on and hanging out in the station also give us important information about conditions of our waters? In this video, Research Associate Mike Doan shows us some of the sea critters that visited the Cage of Science in August.
As always, Casco Baykeeper Ivy Frignoca has been on the move, working across Casco Bay, the state—and the nation—on efforts to protect the environmental health of Casco Bay.
A peek into her appointment calendar shows some of the highlights so far this year, as she continued to track Legislative issues and to comment on proposed wastewater and stormwater discharge permits that the Department of Environmental Protection issues to municipalities.
I became coordinator of the Maine Ocean and Coastal Acidification Partnership (MOCA) for 2018.
I will help coordinate research and advocacy on ocean acidification with a strong statewide network of policy makers, fishermen, shellfish growers, and scientists. This year-long role supports our work examining coastal acidification and excess nitrogen.
I invited Portland’s Water Resources Manager, Nancy Gallinaro, and Portland Water District’s Director of Wastewater Services, Scott Firmin, to travel with me to meet the new Environmental Protection Agency (EPA) Region 1 Administrator, Alexandra Dapolito Dunn. We highlighted our joint efforts to reduce nitrogen pollution, combined sewer overflows, and stormwater pollution to Casco Bay. I shared our data showing the impacts of climate change on Casco Bay.
Administrator Dunn accepted our invitation to come to Maine in June to attend a meeting of the Maine Nutrient Council, a group convened by Casco Bay Estuary Partnership. Afterward, Administrator Dunn will tour the Bay on our Baykeeper boat, a great opportunity for a close-up view of issues that threaten the water quality of Casco Bay.
I traveled to Washington, DC, at the invitation of Ocean Conservancy, to meet with our Congressional delegation and ask for full funding for the National Oceanic and Atmospheric Administration and the EPA. The measures we pressed for passed in the omnibus budget!
Back in Maine, I submitted comments opposing offshore drilling and then attended a meeting hosted by the Bureau of Ocean and Energy Management, to voice Friends of Casco Bay’s opposition to offshore drilling. I supported a resolve that was passed unanimously by our state legislature expressing its opposition to offshore drilling.
I testified at a public hearing as we worked to swiftly defeat a bill that would have practically eliminated the ability of municipalities to pass pesticide ordinances. If you contacted legislators after receiving our email alert about this issue, thank you! The bill was defeated!
I traveled to New Hampshire to attend a meeting of experts concerned about the rise in harmful algal blooms throughout the region, so we could learn more about new species appearing in Casco Bay.
I attended a meeting in West Bath, which drew together people who live and work along the New Meadows River, to discuss how expanding efforts in aquaculture may figure into the many uses of the estuary.
Research Associate Mike Doan gave Kate Simpson and Kayla McMurray, staffers for Senator Susan Collins, a ride to our Continuous Monitoring Station in Yarmouth. I met them at our “Cage of Science” as we demonstrated how we use technology to monitor the Bay hourly, 365 days a year. We explained that though we do not receive funding directly from the EPA, the Agency has a vital role in advising state regulators on strategies to reduce pollution, funding other research, and enforcing the Clean Water Act. This work helps us all protect the environmental health of Casco Bay.
The Maine Ocean and Coastal Acidification Partnership (MOCA) is a volunteer partnership that seeks to coordinate the work of governmental agencies and private organizations and citizens who are studying and implementing means to reduce the impacts of or help adapt to ocean and coastal acidification.
With my colleagues in the MOCA Partnership, I hosted a workshop for nearly 60 scientists, harvesters, policy makers, and advocates on What We Know about Ocean Acidification and Maine’s Lobsters. The event at Bowdoin College featured current research on the effects of climate change on lobsters and emphasized the need for ecosystem-level, long-term studies.
As the year progresses, I look forward to continuing to keep you updated on the biggest issues affecting the health of the waters we all love.
Covered with sea squirts, sea stars, and other marine hitchhikers, the newest member of our monitoring team looks like an abandoned lobster trap. It may be homely, but we are pretty impressed with what it does, collecting water quality data hourly, 24 hours a day, 365 days a year. It is our Continuous Monitoring Station, which will help us answer the question “How are our coastal waters changing over time?” Research Associate Mike Doan calls it “the cage of science.”
It has been just over a year since we placed a carbon dioxide sensor and a data sonde—an electronic device that records temperature, pH, and other characteristics of water quality—inside this modified lobster trap and moored it in healthy waters near the center of Casco Bay off Cousins Island in Yarmouth.
After one full year, we have over 8,760 hours of data on oxygen levels, carbon dioxide, pH (the level of acidity of the water), salinity, temperature, chlorophyll fluorescence (estimated phytoplankton abundance), water clarity, and water depth.
Thanks to our 26-year data set on water quality in Casco Bay, we understand when and which areas of the Bay are likely to exhibit challenged water quality conditions that require further study. Armed with this baseline data, we can now consider how to address the question, How is the Bay changing?
The steady flow of data from the Station already is helping us detect and document how climate change and emerging coastal stressors may be affecting the Bay. Hourly data helps us identify daily, seasonal,
and annual trends to better understand the extent to which ocean acidification may be impacting the water chemistry of Casco Bay. In future years, we hope to deploy two more “cages of science,” one in challenged waters in Portland Harbor and one near Harpswell to help detect the influence the Kennebec River has on Eastern Casco Bay.
What is a data sonde?
A data sonde, such as the one being used by Research Associate Mike Doan, is an oceanographic
monitoring instrument that takes multiple measurements of water quality simultaneously. In
addition to being used as part of our Continuous Monitoring Station, data sondes are used by
staff scientists in other water quality monitoring efforts from shore and by boat. The data is
downloaded to a computer and analyzed to provide a long-term picture of water quality over
time. We thank Casco Bay Estuary Partnership and our generous members for helping fund
our Continuous Monitoring Station’s first year.