Eclipse foreshadows future of state marshes

Tomorrow’s solar eclipse in Connecticut won’t be the total darkening of the sun visible in other parts of the country. Still, everyone who lives near and cares about our coast should pay attention to the effects of this celestial phenomenon. How well the state’s people and wildlife survive the future could depend on it.

Here, the sun will be in partial shadow during the eclipse, but high tide around 9:30 a.m. will be higher than normal, said James O’Donnell, executive director of the Connecticut Institute for Resilience and Climate Adaptation at the University of Connecticut’s Avery Point campus in Groton. Not by much, but the extra gravitational pull from the alignment of the sun and moon will be enough to put our low-lying tidal marshes under a few more centimeters of water than on a typical day.

“As far as marshes go, this is a big deal,” said O’Donnell, also a marine science professor at UConn. “A small change influences how long the marshes remain flooded at high tide.”

More seawater staying longer on the marshes — intertidal zones that are nurseries for fish, nesting and feeding areas for birds and flood buffers for the human landscape — means the saltmeadow cordgrass and smooth cordgrass that paint coastal vistas those vibrant greens and yellows are less able to trap sediments needed to replenish them. It can drown the eggs and chicks of saltmarsh sparrows and other birds that nest on marshes. At tomorrow’s high tide, marshes like Barn Island in Stonington or Pattagansett in Niantic will only have the tips of the grasses poking above the water. They will be crowded with snails and marsh insects that are the base of the food chain, seeking refuge from total immersion.

This would present no challenge to marshes if this were just a once-in-a-while occurrence. The problem, said O’Donnell, is that what will happen tomorrow because of the eclipse is happening more often and more intensely as sea levels continue to rise as the planet warms with climate change. Sea levels as measured at the National Oceanic and Atmospheric Agency’s tide gauge in New London have been increasing about 3 millimeters per year since the 1940s. At the same time water has been rising, the state’s hills and valleys have been sinking about 1 mm per year.

“Seas are rising as Connecticut’s land is going down,” O’Donnell said.

Over the longer term, projections are that Connecticut will see some of the greatest impacts of rising seas “as a consequence of how ocean circulation is changing as the atmosphere and oceans warm,” O’Donnell said. With so much of the state’s cities, towns and neighborhoods built in the flat valleys just above current sea level, that puts large areas of Connecticut at risk for frequent flooding, especially during hurricanes like Irene that hit in late August in 2011, and Sandy that happened in October a year later.

Though the effects of rising seas and warming global temperatures might not sound like a big deal – less than 2 degrees Fahrenheit since 1880 – incremental changes on planetary scales make big differences to plants, animals and people alike.

“Climate change isn’t a hypothetical thing in the future,” said Prof. Chris Elphick, UConn associate professor in the UConn Department of Ecology and Evolutionary Biology and the Center for Biological Risk. “It’s happening now.”

Elphick, along with colleagues from UConn and Virginia Tech, authored a research paper published earlier this month in the Proceedings of the National Academy of Sciences that raises important questions about actions that need to start now to prepare for the future. With funding from Connecticut Sea Grant – which not only supports research but also works directly with coastal communities confronting these issues – the researchers surveyed more than 1,000 owners of properties near marshes to learn the best ways to preserve both the natural and human habitats. Marshes, noted Elphick, are trying to push inland as seas rise, and will need open space along the shore if these critical ecosystems can exist at all.

“There are areas along the coast where parking lots are under water and marsh plants are starting to grow in lawns,” Elphick said.

The research shows the majority of property owners don’t favor giving easements on their property that would prohibit development in areas where marshes are migrating. Though conservation groups often use this mechanism, other strategies had more appeal to coastal landowners. These include restrictive covenants, in which an entire neighborhood agrees to forego armoring their shorelines with seawalls that prohibit marsh migration and can cause erosion and other problems. Another tactic they favor is future interest agreements, in which landowners agree to accept fair market value for their property at the time of signing if future flooding reduces the value by more than half. The future flooding would allow dry upland to turn into coastal marsh.

Overall, the message is clear. Ignoring climate change and sea level rise now will only intensify its effects in the future. The moon and the sun will still be doing their dance in the sky, but the people, plants and animals on Earth below may be in a sweltering, watery and far less habitable world.

Judy Benson is the communications coordinator for Connecticut Sea Grant, based at the Avery Point Campus of the University of Connecticut. She was formerly a staff writer for The Day.

 

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