By ALEX DOMINGUEZ

Associated Press

SOLOMONS, Md.

--Across the environmentally fragile Chesapeake, researchers are spreading out to see what Sandy has wrought. So far, the indications are that the impact has not been as great as last fall when a pair of tropical storms caused widespread flooding that dumped mud, debris and sewage into the bay.

River flow, levels of pollutants, salinity and water clarity are among the items being measured in the bay and rivers, creeks and streams that feed the watershed.

On Thursday, five Department of Natural Resources biologists were on the Patuxent River in southern Maryland aboard the research vessel Kerhin, taking water samples up and down the river.

Near the river's mouth, Laura Fabian dropped overboard a black-and-white Secchi disc, which is used to measure water clarity. She played out line to see how deep the river was at the spot, unable to see the disc after a few feet.

"Secchi is one, air temp is 12, wind is still west at four to six," she yells out, noting the temperature in Celsius degrees. The samples are measured for clarity, salinity and levels of phosphorous, nitrogen, ammonia and related pollutants.

Upriver at Jack Bay, the salinity levels drop in shallower water and the disc isn't visible after about a foot.

"All of a sudden that fresh water is on top," said Debbie Howard, another DNR biologist on board the Kerhin. "This could be the start of the fresh water that's coming down the Patuxent from the storm."

She holds up a gallon milk jug of water from the surface, noting how much browner it is than water taken from a deeper level in that spot on the river.

The trip is a regularly scheduled monthly sampling cruise of the river that happens to come just days after the storm hit, providing early data on its environmental impact.

The National Oceanic and Atmospheric Administration, meanwhile, says its systems of interactive Chesapeake Bay buoys tracked storm data at 10 locations as the storm passed through. The top wind speed was at the Potomac/Point Lookout buoy at 57.9 mph Monday evening, while the maximum wave height was 14.9 feet that morning at the First Landing buoy near the mouth of the bay, NOAA said.