Along the 7,500-mile Gulf of Maine shoreline, forecasters are predicting an extreme high tide Oct. 9. Participants in the first-ever Gulf of Maine King Tides Photo Contest will document how the astronomical high tide that day affects wharves, causeways, marshes, beaches and other coastal settings. Interested citizens are encouraged to join the contest, submitting images from cameras or smart phones.

Organizations from three states and two Canadian provinces are collaboratively planning the Gulf of Maine King Tides Photo Contest, which invites images of coastal settings from Cape Cod Bay in Massachusetts to Cape Sable in Nova Scotia.

Sea levels within the Gulf of Maine have increased more than half a foot over the past century, and scientists anticipate an additional rise by 2,100 of at least two feet, and possibly more than three feet, according to the Gulf of Maine Council on the Marine Environment.

The Gulf-wide contest is part of the international King Tides Project, involving community initiatives that help people envision a world in which sea levels are markedly higher than they have historically been.

Details on contest participation can be found at gulfofmaine.kingtides.net. Photos should be taken around the midday high tide on Thursday Oct. 9 (see local tide charts for exact timing) and submitted online by Oct. 15.

Contest winners, announced by Oct. 31, will receive gifts contributed by Patagonia and Photo Market in Portland. The grand prize is a Fujifilm FinePix XP170 waterproof digital camera, and the two runner-ups will receive Patagonia down sweater jackets.

Organizational partners in the regional King Tides Project include the Gulf of Maine Council on the Marine Environment-Climate Network, King Tides Project, Casco Bay Estuary Partnership, Ecology Action Centre, Envisioning Change/University of Southern Maine, EOS Eco-Energy, Friends of Casco Bay, Great Bay National Estuarine Research Reserve, Maine Geological Survey, Massachusetts Bays National Estuary Program, New Hampshire Coastal Adaptation Workgroup, New Hampshire Department of Environmental Services/Coastal Program, New Hampshire Sea Grant, St. Croix Estuary Partnership, and Wells National Estuarine Research Reserve. Funding support for the King Tides Project comes the Limulus Fund at the Maine Community Foundation.