State environmental officials say they will go to court in an effort to block a plan for seismic testing of the ocean floor off the New Jersey coast.

The National Oceanic and Atmospheric Administration has already approved the testing that's designed to examine ocean sediments as part of a study of climate change and sea level rise.

But a representative of the state Department of Environmental Protection said the department will seek an injunction Thursday in federal court to block the research project.

New Jersey Sierra Club director Jeff Tittel, who said Wednesday he believes it's really about mapping the ocean floor for potential oil and gas drilling, said he's concerned about the environmental effects of the testing.

"People don't realize when they do this seismic testing, it's like an underwater explosion, and those shock waves that go out impact fisheries and actually can hurt and threaten the lives of many sea mammals, especially right whales and dolphins," he said.

Researchers at Rutgers University, the University of Texas, and the National Science Foundation are hoping data from the tests of ocean sediments will help in their study of climate change and sea level rise.

Connie Barclay, a spokeswoman for the NOAA, said the agency acted after extensive scientific review of the plan. It also expanded zones where research would be prohibited.

The Associated Press contributed to this report.