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Post subject: Scientists to monitor ocean's oxygen levels
 Posted: Nov 08, 2006 - 01:02 AM
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Puffer
Joined: Dec 31, 1969
Posts: 73
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Scientists to monitor ocean's oxygen levels
Posted by the Asbury Park Press on 11/6/06
BY KIRK MOORE
STAFF WRITER
NEW BRUNSWICK — On land, it would be as if summer winds pushed in masses of dead, dank air, so heavy that people would flee not just to cool off, but to breathe.
That's what fish experience every summer in parts of the ocean off New Jersey, when levels of dissolved oxygen plunge to dangerously low levels.
Now scientists are planning the most comprehensive effort ever to assess ecological conditions in New Jersey's coastal ocean and bay waters, by checking on animals that can't swim away — clams, worms and other organisms that are cold-blooded "canaries" in the ocean's coal mine.
"In summer almost 100 percent of coastal waters are low-dissolved-oxygen . . . but we don't know if our biological organisms are harmed by that," said Michael J. Kennish, a professor of marine science at the Rutgers University Institute of Marine and Coastal Sciences. "We're looking at the sea floor organisms because they're the best indicators."
The federally funded, $500,000 research effort will go into high gear during summer 2007, when ocean life is at its peak and so are fluctuations in oxygen levels. Findings from all along the state's 127-mile coast could reveal recurring hot spots of environmental problems, with implications for the state's $20 billion tourism industry, beach-oriented businesses and the recreational and commercial fishing communities, scientists said.
Dissolved oxygen in the ocean has been routinely monitored for years. An extreme, widespread low-oxygen event in 1976 killed millions of fish and clams, and pollution incidents crippled tourism in 1987-88. Since then, the U.S. Environmental Protection Agency's water monitoring helicopter has been a familiar sight along the beaches, dipping its sample bottle to collect water quality data.
Compared with the late 1970s and early 1980s, years of data series show improvement in oxygen levels, according to state Department of Environmental Protection reports. But that information is just a small part of the story, said Kennish, an organizer of the planned 2007 coastal assessment.
"Even if the water at the beach looks good, there's still this problem with dissolved oxygen," said Kennish, who has studied the coastal environment since he was a Rutgers student in the 1970s. "There's two things going on here. There's the Hudson River plume and all the stuff that brings down past Asbury Park."
The river flow carries pollutants and nitrogen compounds, called nutrients, that act like fertilizer for microscopic ocean plants called phytoplankton. From the south, summer winds trigger cold currents, called upwellings, that push nutrients toward the surface and trigger phytoplankton blooms near Long Beach Island.
When those tiny plants die in great slicks, they are digested by bacteria "that chews up all the oxygen in some areas," Kennish said. "If you had a very low, widespread dissolved-oxygen event, it would kill everything."
A two-day conference at Rutgers last week brought together scientists from universities, the DEP and the EPA. They emerged with a list of recommendations, from analytical models to novel hardware, such as a prismatic camera that EPA scientists to take pictures of animals where they live.
Traditionally, scientists use probes that grab samples of bottom muck. With the camera, "basically you're just driving the boat and dropping the camera on station," said EPA scientist Giancarlo Cicchetti.
When the device lands on the sea floor, the prism pokes into the mud, allowing scientists to take cross-section photographs of the sediment and the small animals living there. The differences in those photos — light-colored mud and burrowed worms in healthy water, and black, dead silt in polluted zones — are "a very effective tool for communicating these conditions to the public," Cicchetti added.
The Department of Environmental Protection uses fairly complex criteria, approved by the federal Environmental Protection Agency, to analyze freshwater environments at 800 locations around the state. DEP officials say they want a saltwater methodology that's as technically reliable — and thereby defensible in court, in case industry or environmental activists challenge it.
There are 17 sewage treatment plants discharging their treated water to the ocean through 14 outfall pipelines, and this project will include the first comprehensive look at how dissolved nutrients in that water affect the ocean.
"Every time you see low dissolved oxygen, everyone jumps up and points a finger at the discharges," said Nancy Immesberger of the DEP's water quality unit. But low-oxygen events may be more influenced by the Hudson River plumes and upwellings, she added.
Copyright © 2006 Asbury Park Press. All rights reserved.
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