Archive for February, 2013

Heavy Metal Movers

Tuesday, February 12th, 2013

wood frogs

Juvenile wood frogs emigrating from their birthplaces in vernal pools into the terrestrial ecosystem may transfer mercury they accumulated during larval development into the food web, according to a team of University of Maine researchers.

The team, led by U.S. Geological Survey and UMaine wildlife ecologist Cynthia Loftin, conducted its study at four short-hydroperiod (likely to dry by mid-June) seasonal woodland pools in Acadia National Park on Mount Desert Island, Maine.

The researchers found mercury levels in the 1- to 2-week-old embryos were near or below detectable amounts, indicating that transfer of mercury from mother to eggs was absent or minimal. However, mercury accumulated rapidly in the 6- to 8-week-old tadpoles.

Mercury, a heavy, toxic metal, occurs naturally and is introduced into the environment by metal processing, coal burning and mining. People are exposed to mercury by eating contaminated fish and wildlife. Over time, low-grade mercury exposure in people can impact cognitive thinking and fine motor skills.

While concentrations of total mercury differed among the pools and were greatest in the unburned softwood-dominated setting, the levels increased in all pools throughout the season. The pools dried in June and refilled with September and October rain.

Wood frogs can travel some distance from their natal pools. During summer, fall and winter, they live in wetlands and on land. In the winter, they hibernate underneath leaf litter, woody debris and soil. They return to pools in the spring to mate.

For a better understanding of the transport of this contaminant from seasonal pools into the surrounding environment and potential for uptake into the terrestrial food web, future studies should focus on the ratio of total mercury to methylmercury (produced by burning of fossil fuels) in embryos, tadpoles and juvenile frogs leaving natal ponds, according to the research team, writing in the journal Northeastern Naturalist.

Loftin teamed with Aram Calhoun, professor of wetland ecology; Sarah Nelson, assistant research professor at the Senator George J. Mitchell Center; Adria Elskus, associate professor of biological sciences; and Kevin Simon, assistant professor in the School of Biology and Ecology, to conduct the study.

Research Explores How to Empower Sustainability Stakeholders Today and in the Future

Tuesday, February 12th, 2013

SustainabilityEncouraging people to be engaged in sustainability efforts today that will make a difference tomorrow begins with a look back, says a team of University of Maine resource economists. Reflecting on societal decisions that have come to bear and learning from those aspects that we regret, or for which we are grateful or indifferent could lead to the ultimate motivating question: What actions will the future regret and what will it be thankful for?

Retrospective thinking — learning to evaluate reactions to the legacy we leave — is a means of raising awareness of the potential implications of current actions on the future, according to UMaine School of Economics researchers Mark Anderson, Mario Teisl and Caroline Noblet, writing in the journal Ecological Economics.

It is broadly understood that successful sustainability awareness and action require intergenerational equity and stakeholder engagement. It also is generally argued that we cannot presume to know future preferences — both individual and collective — that change over time.

For a community to engage the future as stakeholders in sustainability, the researchers propose four steps, which will be tested in a survey this spring.

  • A broad cross section of community members think about previous societal decisions they are grateful for, indifferent to or regret.
  • Participants discuss their regrets and gratitude in small group settings to identify common elements of past decisions to help uncover the community values expressed in historical regret or gratitude.
  • Common elements are used in a survey of the whole community to gauge consensus.
  • Community groups consider the survey data and how this information helps people think about future reactions to current decisions.

“Reflecting on what about previous decisions contributed to or detracted from sustainability is a concrete exercise in intergenerational thinking,” according to the economists, whose research is supported by Maine’s Sustainability Solutions Initiative, a program of UMaine’s Senator George J. Mitchell Center.