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Images: Water Flowing Underground

WHOI Postdoctoral Scholar Kevin Kroeger and Guest Student Kayla Halloran install a well in Eastham, Mass., to sample groundwater seeping into a salt pond. Between 5 and 10 percent of the fresh water in the ocean comes from groundwater seeping through submarine sediments. (Tom Kleindinst, WHOI Graphic Services.)

WHOI Associate Scientist Matt Charette (left) and Research Assistant Matt Allen use pumps and instruments deployed on a canoe to collect water samples from Pamet Harbor in Truro, Mass. By measuring the amount of dissolved radon and other chemical tracers—leached naturally from rocks or introduced by septic systems—they can measure the flow of submarine groundwater into the coastal ocean. (Tom Kleindinst, WHOI Graphic Services.)

HYDROLOGIC CYCLE IN COASTAL ZONES—Precipitation either evaporates into the atmosphere, gets taken up by plants, flows into streams, or infiltrates the ground and recharges aquifers. Groundwater flows from inland locations to lakes, streams, or coastal waters. On the seaward side, denser salt water enters sediments and establishes equilibrium with fresh groundwater. Tides and mixing along the freshwater-saltwater interface results in seawater circulation through the sediments.

COOL VIEW OF GROUNDWATER—Infrared images shot by airplane in September 2002 reveal the extent of groundwater seeping into Waquoit Bay, Mass. Bright yellows indicate locations where cool groundwater is emerging from the sandy bottom into the salty, warm waters of the bay. (SenSyTech, Inc. and Ann Mulligan, WHOI.)

GO WITH THE FLOW—WHOI Assistant Scientist Ann Mulligan (foreground), Research Assistant Meagan Gonneea (blue shirt), and visiting student Claudette Spiteri collect data about groundwater discharge into Waquoit Bay, Mass. By measuring water pressure, temperature, and conductivity, they can monitor how fast groundwater is flowing and how the interface between fresh water and salt water changes over time. (Tom Kleindinst, WHOI Graphic Services.)

Research Assistant Matt Allen sits on an airboat and sets up a WHOI-designed automated seepage meter for a three-week deployment in the Florida Everglades. (Matt Charette, WHOI)