An aquatic ecologist in the College of Agriculture and Life Sciences is trawling the Hudson's depths, hauling up fish and invertebrates to find out whether dredging after the 2001 terrorist attacks stirred up contaminants and harmed life at the river's bottom.

Two days after the Sept. 11 terrorist attacks, James Ortenzio, who was chairman of the Hudson River Park Trust, took action to set up the path for debris removal from the World Trade Center out of Manhattan. He also began thinking about the environmental impact of the debris removal process.

Ortenzio got in touch with the U.S. Army Corps of Engineers to figure out a way to get an emergency permit to dredge a few parts of the Hudson River around piers along Manhattan's lower west side to allow barges and tugboats to get into the area. By that Friday at noon, dredging began and took a week to complete. The next Tuesday, debris was being removed from the site and loaded onto barges just four blocks north of the World Trade Center site. Ultimately, more than 100,000 truckloads (71 million tons) of debris took this route.

It was on the day the dredging began that Ortenzio realized that the river bottom had been invaded by a massive scoop that might have long-term consequences to the Hudson's aquatic life. He felt a particular concern since the Hudson River Park is an organization of the city and state of New York that is redeveloping New York City's waterfront from Battery Park through 59th Street-more than five miles of Manhattan's coastline.

"To dredge a river is quite serious, and it would have taken probably years to accomplish what had been decided in one morning," Ortenzio says of the granted permits. "I realized we were disturbing, without process, something that we all consider to be valuable-the river bottom."

As a member of the Cornell University board of trustees at the time, Ortenzio asked the university for help.

 

The following Monday morning, Ortenzio called then-Cornell President Hunter Rawlings and explained that he needed to begin some sort of environmental assessment and needed an aquatic ecologist. Rawlings put him in touch with Mark Bain, director of Cornell's Center for the Environment and an associate professor in the College of Agriculture and Life Sciences' Department of Natural Resources.

Bain quickly learned that about 120,000 cubic yards of river bottom had been removed at Pier 25, with additional dredging at Pier 79 and Pier 6. The dredging alone--even without considering the possible air--and dust-borne toxins from the 9/11 attacks settling into the Hudson-could have stirred up contaminants in the river bottom that had been untouched for decades.

Bain, who was already familiar with the Hudson River area from studying the Hudson's shortnose and Atlantic sturgeon, first went down to the site in early October 2001. "The building site was still smoking and the debris they were putting in the barges was still smoking," Bain recalls.

Seeing the site presented Bain with a completely new challenge. "We had never done sampling or studies on fish or invertebrates in an urban area like that," he says of his research team. "I didn't have any idea what kind of sampling gear we would need or what the logistical problems would be."

Bain secured funding from the Hudson River Park Trust in two one-year grants, and he was able to begin the study in the summer of 2002. It will last through this summer.

This assessment will eventually provide information and a recommendation to New York State and the city regarding how to best proceed with recovery of the river environment from the 9/11 disaster.

The eight study sites are fairly evenly spaced from Battery Park to Pier 95, which is nearly as far uptown as the south end of Central Park. Only one site, Pier 25, includes a dredging impact area just off Battery Park, where debris removal barges spent time for months. For a week each month, Bain's team of four field researchers visits each of the eight sites, trawling four times with a 20-foot otter trawl and dropping a grab sampler four times, generating 64 samples a month.

The otter trawl is a drag gear, kind of like a big weighted net bag that rides along on the bottom, capturing fish and lots of other large debris. The grab sampler, which retrieves substrate in 9-inch by 9-inch parcels, is used for the invertebrate sampling, says Geofrey Eckerlin '01, Bain's field crew leader and a technician in the Department of Natural Resources.

The fish are measured, weighed, and examined for any external physical anomalies, and released. The invertebrate sampling takes longer, since the huge bucketfuls of muck have to be strained, the sediment contents sorted and stored in preservatives to be examined and identified with 40x magnification later at a lab.

Bain doesn't have enough analyzed data from the invertebrates to come to any conclusions, but he says that based on the fish and other river-bottom organisms they have caught and examined, the variety and health of the aquatic life they have found looks typical for the type of estuary, brackish-water area of the East Coast that this part of the Hudson River should represent. The river appears to be supporting the variety of fish it should. "It's not polluted nor dead, which is a perception a lot of people have," Bain says of what was true of the oxygen-starved Hudson River of 30 years ago.

The greater worry may still be the impact on the several dozen species of invertebrates. Since the area around Pier 25 was deepened and dredged considerably, the actual living space of these invertebrates was drastically changed. "They have a greater chance of showing effects because their actual living space was removed," Bain says. Much of the debris that settled out of the smoke and toxic clouds from the World Trade Center site may have also sunk to the bottom of the river and settled there, in addition to whatever contaminants the dredging might have stirred up.

"So far, we don't have any observations from our work that suggest that the dredged area is different than the undredged parts of the New York City coastline," Bain says. "If that conclusion persists, we would be saying that there wasn't any real change made by the dredging, which would be fine."

At the end of the two-year study, Bain will make a recommendation which could suggest putting the dredged area back the way it was or leaving it in its new deepened state. The study will also have the benefit of giving the Hudson River Park valuable information about its waters.

"It has been a couple of decades since anybody had sampled fish and aquatic life in the park area," Bain says. "During that time, water quality has improved greatly in New York Harbor. Early in the period of this waterfront improvement, there were still times when there was no oxygen in the water, in the '60s and '70s and even into the '80s. Now, there are really good conditions for fish all the time," Bain says.

Bain's study also documents the high productivity of an estuary like the Hudson River-a mixing zone between marine and fresh water. An estuary supports the early life and growth of many species of fish, many of which, like bluefish and striped bass, are commercially important. Estuaries tend to be populated by very transient types of aquatic life because of their nature as a transitional habitat.

"It's very different than what you would see in a stream, lake, or in the ocean," Bain explains. Some species are only found in the water at certain times of the year, and there are definite population peaks and valleys.

"All this is evidence that the place is functioning, and the environment appears to be supporting normal types and varieties of estuarine fish," Bain says.

- Joe Wilensky