75 kilograms of dye used to understand ocean mixing dynamics

Researchers released 75 kilograms of rhodamine dye into the Atlantic Ocean, 28 kilometers south of Martha’s Vineyard, Massachusetts, to track water movements and mixing dynamics beneath the ocean surface.

In the study published in the journal Continental Shelf Research, approximately 130 gallons of a rhodamine-ethanol mixture were pumped into the ocean using the research vessel R/V Connecticut. This neutrally buoyant chemical tracer allowed scientists to mark and track a specific water mass.

As a result of observations lasting approximately 33 hours, it was determined that 99 percent of the dye remained in the mixing layer near the surface. The data showed that vertical mixing in the surface layer was approximately 140 times faster than the transition to the lower layer. Researchers stated that density differences beneath the surface acted as a natural barrier and that vertical seepage into deep waters was a slow process spread over days.