Scallops return to Barnegat Bay

Research professor Michael Kennish: This is really exciting. Scallops were totally decimated years ago, and now they're coming back. "Around 50 years ago, these things were really plentiful." The scallops' reappearance is one bright spot in the troubled modern history of Barnegat Bay, years that have seen native fish and plant species fade away, and even a near-disappearance of the bay's once mighty clam resources.

Using such high technology as robotic submarines along with old-fashioned hand sampling, they aim to document how pollution affects coastal bays and the natural communities that live there. Their findings have enormous implications for New Jersey's coastal communities and their quality of life because contamination coming from the bay watersheds and air pollution fallout "affects the entire structure and function of the ecosystem," said Kennish, who lives in Dover Township not far from the bay. "Usually the organisms that like it are the kind of things people don't want to see."

Most studies of coastal ecosystems focus on the "water column," scientists' shorthand for top-to-bottom chemical conditions in the water, Kennish explained. The Rutgers research goal is to connect water conditions with the state of animals and plants on the bottom, and thus develop a "biological indicator index" that will document the connections between life and the water.

"The bottom community is critical for that because these organisms aren't mobile. They can't swim away like fin fish when the conditions change," Kennish said. "It hasn't been done before in New Jersey, and this particular method hasn't been tried anywhere before."

What eelgrass shows: There's a long-held notion that bay ecosystems will bounce back with improving water conditions, but that assumption has been alarmingly wrong in the Barnegat region. For most of the 1990s, state environmental officials could announce water quality improvements that allowed more and more areas of the bay to be reopened for shellfishing. But even as seasonal bacteria counts went down, so did the numbers of clams in the bay. One state survey estimated that clam resources in Little Egg Harbor, at the southern end of the Barnegat estuary, plunged by two-thirds between the late 1980s and 2001, and show no sign of regaining their former numbers.

From the university's Institute of Marine and Coastal Studies field station in Little Egg Harbor Township, field researchers ride out to conduct an array of projects, from mapping the bay bottom with autonomous submersibles, to studying its eelgrass meadows. That's where researchers Haag and Greg Sackowicz find the scallops, just one of a whole suite of animals that shelter and feed among the long fronds of underwater grass.

Stormwater runoff carries pollution from parking lots and housing developments to bay tributaries: nitrogen compounds from excess lawn fertilizer and animal waste, pesticides, oil from car engines. Some of that material acts as plant nutrients and feeds persistent outbreaks of microscopic algae that reduce the sunlight reaching eelgrass, Kennish said.

So "sea grass is a good indicator because it's very sensitive to the amount of light in the water," explained Lathrop, who's director of the Rutgers center for remote sensing and spatial analysis. He oversees the matching of data and geographic locations, techniques that "follow what's happening in the watershed all the way down to the bay."

"When damage is happening from nutrient levels, it starts at the microscopic level," said Kennish, who has warned for some years that consequences of nonpoint-source pollution have been underestimated. Nutrients also feed mats of macroalgae, large expanses of simple plants such as sea lettuce that have overrun eelgrass beds and other areas of the bay, Kennish said.

"It's like a quilt. There's patches of sea lettuce all over," he said. "It kills the benthic community (organisms that live on the bay bottom). The organisms can't deal with it. It also damages the exchange of gases between the bottom sediments and the water column. So it's affecting the basic chemistry."

The work that's being done in Barnegat Bay will help uncover water pollution and natural resource problems all along the state's 127-mile seacoast and in its coastal bays and estuaries, Kennish said. The ultimate goal, he said, is to "develop indicators of ecosystem health for the sea-floor communities in the near-shore and estuary waters of New Jersey." [org pub Asbury Park Press, written by Kirk Moore]