Changing climate is messing up the transition to spring

  • The arrival of the dark-eyed junco ending its winter migration is one of the early signs that spring is about to arrive in Merrimack County. Courtesy—

Granite Geek
Tuesday, March 14, 2017

It’s seven degrees outside as I write this, and it’s probably snowing like crazy as you read it, but let’s ignore reality and talk about the transition to spring.

The geeky angle? According to research led by UNH, the seasonal shift out of winter is only starting earlier but is taking longer than it used to. You can guess the reason.

“Historically, the transition into spring is comparatively shorter than other seasons,” said Alexandra Contosta, a research assistant professor at the UNH Earth Systems Research Center, as quoted by UNH News Service. “You have snow melting and lots of water moving through aquatic systems, nutrients flushing through that water, soils warming up, and buds breaking on trees. ... Things seem to wake up all together, which is why spring seems to happen so quickly and can feel so dramatic.”

However, snow cover in the Northeast has declined significantly in the past 30 years, which is no news to disgruntled skiers. Researchers wondered what effect this climate change-induced decline is having on the timing and duration of our “vernal window,” the delightful science term for the transition.

So they looked at three years of data from soil and water sensors that monitor snow levels and the forest canopy across the state, plus climate and satellite data, and a final topping of precipitation and stream data collected by more than 100 volunteers hither and yon. They were interested in the dates of events such as snow melting and leaves emerging, and at the amount of time between these events.

Their findings, published online in the journal Global Change Biology, said that warmer winters with less snow have resulted in a longer period between spring events, and thus a more protracted vernal window.

That change can affect all sorts of things – from treehugger issues like songbird populations, which suffer if the life cycle of certain edible insects gets out of whack with hatching cycles, to pocketbook issues like transportation costs, which go up if a longer mud season extends the period for delivery-truck-confounding weight limits on town roads.

New Hampshire EPSCoR’s Ecosystems & Society project includes a host of co-authors including some from Dartmouth College, Keene State College, Plymouth State University, Saint Anselm College and White Mountains Community College.

Update: Drilled wells may not be safer than dug wells, after all

Last week’s Granite Geek, which discussed research into arsenic and related elements in New Hampshire wells, contained a misleading statement.

By “misleading” I mean, of course, “wrong.”

In the column I compared wells that have been drilled deep into bedrock vs. shallow wells dug into sand or soil, and said that drilled wells were “safe from surface pollution.”

Nope. In fact, studies of MtBE, a pollutant associated with gasoline that has tormented New Hampshire, find that in some geological circumstances drilled wells are actually more affected by surface pollution, not less.

That possibility is raised in two papers from the U.S. Geological Survey, in cooperation with New Hampshire Department of Environmental Services, that were brought to my attention by Joseph Ayotte, chief of the Groundwater Quality Studies Section of the USGS office in Pembroke.

One study found no difference in pollution between the two types of wells.

“Concentrations of MTBE detected in this study were not significantly different ... in unconsolidated wells than in bedrock wells,” said a study by Ayotte and colleagues published in Environmental Science Technology. (“Unconsolidated” is geology-speak for sand and gravel and other “discontinuous glacial deposits that overlie the bedrock,” so an unconsolidated well is a dug well.)

More surprisingly, a later report in the same journal by Ayotte and colleagues, looking at trends in MtBE in southeast New Hampshire from 2005 to 2015, found that some drilled wells actually hold onto the pollution longer than dug wells.

“The shallow glacial-aquifer wells had a 100% decrease in the MtBE detection frequency between 2005 (33.3%) and 2015 (0%), owing to higher porosity, greater rates of dispersion, and greater ability to dilute contaminants than do fractured bedrock aquifers,” it said.

In other words, drilled wells were polluted by MtBE just as much as dug wells were, and sometimes they stayed polluted for a longer period.

Why? It seems that, in certain geological circumstances, the fractures in bedrock that water moves through act almost like straws, allowing polluted water to travel farther – and hang around longer – than the water oozing into your well through sand and gravel.

Whatever the geology, the lesson is this: Just because you have a drilled well doesn’t mean you can sit back and feel safe, regardless of what some doofus of a newspaper columnist says. Test your well water regularly.

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)