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On the Shelf

We’ve left port and are steaming east, northeast towards our first station. We will be cruising along the shelf at 11 knots for the next few days.

Our first station will be in an anticyclonic eddy near 50 degrees N (this is eddy A1 in the map below).

Map of our cruise and track and eddies.

Map of our cruise and track and eddies.

It’ going to take us another 6 days to get there. During the transit, samples are being continuously analyzed from the through-flow system which takes sea water from just below the surface and pumps it through a multitude of instruments.

chogram
We have also started to collect acoustic data using the ship’s acoustic doppler current profiler (ADCP). Although this is an echosounder that is designed to measure ocean currents, but I’ve also been looking at the amplitude of the acoustic backscattering in the water column. Yesterday around sunset, we observed the vertical migration of zooplankton and micronekton (little beasties that eat smaller beasties and plants) to the surface. It was exciting to watch this unfold in real-time.

At the same time, we started to see these little critters in the imaging flow cytobot.

ifcb

Check back in a day or two and I’ll post a short video giving a tour of the ship, our home for the next month.

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Has Lydia found a new eddy?

There has been lots of excitement recently about Lydia, an approximately 2,000 lbs. white shark, and her recent eastward movement offshore towards a region populated with large Gulf Stream eddies. Until yesterday, Lydia was moving mostly due east. But now, she has taken a sudden turn north. To investigate if her change in course could be cued by the presence of a particular eddy, I overlaid her track on a map of near-real time SSH (data from http://eddy.colorado.edu/ccar/ssh/nrt_global_grid_viewer).

Sure enough, her turn to the north puts her in the region of a large anticyclonic (clockwise rotation) eddy or meander, characterized by warm water low in chlorophyll (algae).  We’ll have to see where she goes next to find out of she decides to stay in this eddy, or keeps moving north-northeast.

Lydia's track (starting Nov 4th and ending Nov 24th, 2014) overlaid on a map of sea level anomaly (often referred to as SSH, sea level height).

Lydia’s track (starting Nov 4th and ending Nov 24th, 2014) overlaid on a map of sea level anomaly (often referred to as SSH, sea surface height).  Track data courtesy of ocearch.org and SSH data of the Colorado Center for Astrodynamics Research (CCAR).