The heterocomplex undergoes cycles of association and disassociation to transfer one electron, which is the rate-limiting step in nitrogen reduction .

And studies have shown that the low level of oxygen in the water, which nitrogen reduction was supposed to correct, is a more complicated issue than previously thought.

The plan's priorities include nitrogen reduction, habitat restoration, storm water control, sewer overflow abatement and sediment remediation.

While New York City received an A minus for nitrogen reduction, it received only a D for controlling non-point source pollution.

By contrast, Connecticut received two A minuses - for nitrogen reduction and petroleum-spill prevention.

Instead, the Connecticut D.E.P. cut back on grants and loans - and on the size of the nitrogen reduction it will require.

The Citzens Campaign for the Environment Long Island Sound Report Card gave Connecticut A- scores, for nitrogen reduction and petroleum spill prevention.

New York City, while also getting an A- for nitrogen reduction, rated only a D for controlling nonpoint source pollution.

Nassau County's best score was a B+ for non-point source pollution; its worse score was a C- for nitrogen reduction.

Different mixing rates, in turn, can compound the problem of low oxygen that kills the animals that local governments are working to save through nitrogen reduction.