New York Harbor Summer 2002
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The goal of the project was to study the flow and mixing of water in the inner part of New York Harbor, including Newark Bay, the Kill van Kull, the Arthur Kill, and parts of the Passaic and Hackensack rivers. This knowledge adds to our understanding of the transport of dissolved substances, including contaminants introduced by heavy industrial use and intense shipping activity.

The study begins with the injection of a small amount of an inert gas tracer, sulfur hexafluoride (SF6), into upper Newark Bay. Measurements of SF6 throughout the study area were taken for 12 consecutive days to study the spreading and mixing of the tracer-tagged water. Tracking the tracer patch allows direct visualization of the spreading and mixing of certain contaminants, while simultaneously yielding fundamental data about the underlying physics of the estuary.

The New York/New Jersey Harbor is of great economic importance to its surrounding communities. Large cargo vessels such as the one above, as well as oil tankers, are common throughout the area. Newark Bay and the Kills are lined with refineries and port facilities for tankers, container ships, car carriers, and bulk carriers.

The Riverkeeper, a 36-ft work-boat carrying the tracer monitoring equipment, including our near-real-time gas chromatography flow-through sampling system, is an ant compared to the shipping traffic found in this region.			The Hackensack and Passaic rivers deliver both dissolved and sediment-bound contaminants to the Inner Harbor. Due to ever-larger ships, the navigation channels are periodically dredged, resuspending sediments laid down in prior years.
John secures the pump mount onto the boat. The submersible pump is lowered to a depth of 1 meter. The water flows into the extraction system where gases, including SF6, are stripped out. The concentration of SF6 is then determined by onboard gas chromatography.			Nick prepares for a CTD cast near Liberty Island. The CTD provides a profile of the salinity and temperature structure throughout the study area.
Ted uses a tape measure to make sure the boat will safely pass under a bridge on the Passaic River after the tide rises.
Rica checks the water flow rate of the extraction system.			Peter and Ted prepare for SF6 injection in upper Newark Bay, July 13. "Injection", in this case, meant bubbling less than a mole of trace gas into the water from a depth of about 6 meters.
Peter takes a depth profile of the water column. In an estuary, water dynamics are greatly influenced by the interaction of saline ocean water and fresh river water. Tracer depth profiles, along with CTD profiles, provides a better understanding of the vertical density structure of the water column, and the ease with which dissolved substances will mix vertically.			Nick takes water samples for CFC's for a parallel study. Tracer studies can help identify where dissolved contaminants, like CFCs, will more commonly go.

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