A Watershed Year in Monitoring Our Waters

Posted on Nov 20, 2011

Saturday, October 15th, 2011, marked the last sampling day of the season for our volunteer water quality monitors and, more importantly, the completion of the 20th year that our Citizen Stewards have been collecting data for Friends of Casco Bay.

Peter Milholland, who has been the Citizen Stewards Coordinator for over 16 years, says most Citizen Stewards stay for five years or longer; some have been sampling for nearly two decades. “While we have some retirees, most of our volunteers work full-time in a variety of careers. Most are not professionally-trained scientists. Whatever their background, they are all drawn by their personal connection to the Bay to devote their ‘free’ time to monitoring its health. That sustained volunteer involvement has strengthened the credibility of our long-term data set.”

Why is 20 years of data noteworthy? “Because it is long enough to show a trend,” says Research Associate Mike Doan. He has analyzed what two decades of water quality data tells us about the health of Casco Bay. “Water quality in Casco Bay is generally good, and the long-term trends in dissolved oxygen concentrations are encouraging. Dissolved oxygen, of course, is necessary to sustain marine life. Oxygen levels of the surface water have slightly but significantly increased at all but one of our water column profile sites.

“At the shoreside sites, which our volunteers monitor, the average water temperature has increased by 0.1o C over 20 years. Down through the water column, at the deeper-water sites that our staff members sample by boat, we’ve seen a smaller increase in water temperature. More worrisome, though, is that these sites show a significant decrease in pH, which means that Casco Bay is more acidic than it was 20 years ago. These are troubling trends that we are watching intently as we continue to collect data.”

Time discovers truth. — Seneca, Roman philosopher

Long-term monitoring enables researchers to recognize subtle changes
over time. Continued monitoring is also needed to assess the impact of
actions taken to resolve a threat to the environment or to public health. The
National Science Foundation defines long term as “decades to a century.”
Studies like the ones below are still revealing new truths.

Penguin Food

A study begun in 1975 links Adelie penguin populations to the expanse
of pack ice that builds up around Antarctica each winter. This is because
shrimp-like creatures called krill, the penguins’ principal prey, spend
their first winter tucked into crevices in the underside of the ice. Winter
temperatures on the Antarctic Peninsula have warmed by almost 6o C since
1950, more than five times the global average. Warmer temperatures = less
ice = less krill survival = fewer penguins. Researchers today count only
a quarter as many Adelie penguins on the western Antarctic Peninsula as
they did in 1975.

Photographic Evidence

Photos don’t lie! Photographs of trophy fishes caught by Key West charter
boats from 1957 to recent times provide graphic evidence that these Florida
natives have gotten smaller, thanks to a half-century of overfishing and
habitat destruction. Today’s prize-winning groupers, snappers, and sharks
likely would have been thrown back in 1957!

Human Health

In 1948, more than 5,200 adults in Massachusetts enrolled in the
Framingham Heart Study. Among other ground-breaking findings,
this study was the first to show how diet and cigarette smoking impact
incidences of heart disease and stroke. Still the longest-running study of
human health, it is now tracking the grandchildren of those first volunteers.