Robots and Gulf Stream: Looking at Continental Shelf Meets Gulf Stream

In new ocean-robot findings, a research project off the Massachusetts coast learned more about how warm Gulf Stream currents and chillier waters along the continental shelf combine and exchange. This happens when the waters offshore, which arrive from the tropics, barge onto the Mid-Atlantic Bight shelf and run into waters that came from near-Arctic regions, according to a release.

Altogether, the interaction between the two water types can have a powerful effect on biogeochemistry, fisheries and circulation on the shelf. "Normally, the Gulf Stream water, which is very warm and buoyant, doesn't come in direct contact with the water on the continental shelf, which is much colder. There is a cascade of potential implications that need further study," said Weifeng ‘Gordon' Zhang, at Woods Holes Oceanographic Institution (WHOI), in the release.

While scientists have known since 2006 that there was a long body of warm water along the shelf edge--the result of an extended part of the Gulf Stream--and that it extends from Massachusetts toward Cape Hatteras, N.C., they only recently were able to study that phenomenon. Their findings regarding it were published in the journal Geophysical Research Letters.

In order to conduct the study, the team used autonomous vehicles called "gliders" to gather data in a pre-planned path in the ocean. These robots collected data from April through June 2014. From this data, the scientists learned that the long extensions of warm water are nearly 100 meters deep, nearly to the seafloo, according to a release.

The team thinks the interaction between these two waters might help certain fish, like American eel, to cross the shelfbreak barrier and swim toward coastal estuaries. This may increase the survival rate of young eels. For other marine life, the warm-water intrusion might lower the nutrients in the water, bringing in less-dense Gulf Stream surface water and tamping down the cold, nutrient-rich water that would normally be there, said the release.

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