A torpedo ripped through the port side of the passenger-freighter, City of Atlanta, and sent her to the bottom of the Outer Banks near Cape Hatteras. U-123 captain Reinhold Hardigan had found his fifth victim that night in the winter of 1942.

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Now, the wreck of the City of Atlanta is an artificial reefs and popular diving attraction.

During World War II, German U-boats and friendly minefields took a deadly toll of U.S. ships right off the North Carolina coast, near the famous civil war wreck, the Monitor. A National Oceanic and Atmospheric Administration (NOAA) study recently looked at the marine ecosystems supported by these WW2 era shipwrecks.

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They found that different wrecks supported different communities of fish and other species. They also placed temperature sensors to gather data which may corroborate evidence that the waters off North Carolina are warming and becoming home to more tropical species.

In June of 2010, NOAA researchers studied the wrecks of the Keshena, City of Atlanta, Dixie Arrow and EM Clark. They surveyed fish populations as well as other marine organisms, and determined that wrecks at different depths were home to different mixes of species. In general the mid-depth waters (20-40 meters) supported greater biodiversity.

While that was not surprising, the population survey established a baseline for watching changes in marine ecosystems as the waters warm up. North Carolina’s marine communities are made up of a mixture of temperate and tropical species, due to the states’ geographic location in a transition zone between north and south.

The Gulf Stream affects the southern portion of the state’s waters around the wrecks of the Keshena and Dixie Arrow. Whereas the colder Labrador and Virginia currents affect the area north of Cape Hatteras, around the wreck of the City of Atlanta.

Warmer waters allow fish and other creatures more frequently found further south to move north. The NOAA study cites other research which found an increase in tropical animals off North Carolina as well as tropical algae species never before seen in the area.

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The NOAA team placed sensors on the Keshena, City of Atlanta, Dixie Arrow and EM Clark, as well as another shipwreck, the Manuela. They hope to use the data collected by these sensors to monitor changes in the ocean’s temperature for use in future studies.

IMAGE 1: Wreckdiver in the Channel Islands National Marine Sanctuary (Wikimedia Commons)

IMAGE 2: Composite side-scan sonar image released by the National Oceanographic and Atmospheric Administration (NOAA), of the wreckage of a World War II patrol boat in approximately 300 feet of water off the coast of Cape Hatteras, N.C. (Wikimedia Commons)