Presenter: Patrick Gray (Duke Marine Lab)

Description:
Strong persistent fronts, such as the Gulf Stream’s north wall, are reliable hotspots of submesoscale dynamics, linked to increased productivity in phytoplankton, zooplankton, and fish, and represent a hotspot of ocean predator diversity. The Gulf Stream front just downstream of the current’s separation point at Cape Hatteras, N.C. provides an ideal observatory for investigating physical-ecological interactions. This area of intense fine-scale variability is the interface of two contrasting biogeochemical provinces, and contains many communities rapidly transported from further upstream. In two recent cruises we investigated how the fine-scale physical environment of the front structures biological communities in this region. This was done with a range of methods including tightly spaced vertical profiles, active acoustics, sampling for DNA, flow cytometry, and nutrients, ocean color drone surveys, and an array of inline optical and chemical sampling. We will present early results on the observed biophysical environment and contrast our two cruises, the first of which captured the front without any dominant submesoscale features and the second which captured a large frontal eddy moving through the study region.