The Seascapes

The Seascapes

Friday, August 20, 2010

A brief pelagic interlude

Densities measured with CTDs along the 4 transects on which we 
collected depth stratified plankton samples with a tucker trawl from 
August 9-12, 2010.   
I am trying hard to focus on the analysis of differences in fish and invertebrate bottom communities in the seascapes to follow up the last post about our bottom sampling methods.  But sometimes fun stuff happens.  First, Chip Haldeman from RUCOOL plotted up the density data we collected with CTDs during our plankton cruises last week. His waterfall plots are just too cool not to share.  Notice the highest density water (darkest red; cold & salty) in the head of the Hudson Shelf Valley in deep water off New Jersey.  The Steven's institute NYHOPs model showed a slug of cold salty water off the mouth of the estuary which could have welled up along the shelf valley. We had strong upwelling conditions all of last week. We tried to sample the plankton in the cold water on August 11th along the New York transect oriented southwest to northeast in the plot above. The positions of our tucker trawl tows on the NYHOPs model temperatures on the 11th are shown immediately below.
 Positions of the tucker trawls on NYHOPs forecast 
temperatures on August 11, 2010 showing the cool water
off the mouth of the estuary. This transect is also shown
stretching southwest to northeast in the plot above. 

RUCOOL used our CTD data to decide how to ballast a robot glider launched today off Sandy Hook.  The glider is to fly from Sandy Hook south to Cape May, New Jersey in a zigzag pattern from the near shore to 40 km offshore.  The glider will provide Steven's institute with temperature and salinity data to better tune the NYHOPs model for near shore forecasting.  It is also equipped with a dissolved oxygen and other optical sensors that will be used in the State of New Jersey's water quality monitoring program. This is exactly the kind of model tuning and habitat condition data we need to do our seascape work better.

At the last minute RUCOOL asked us if we could help with a vessel to launch the glider.  This was invitation for real fun.  Below are some pictures of the robot glider launch and a pod of porpoises that we saw on the way home. The mission of glider RU-16 over the next few weeks can be followed here.

Location where we launched the RU-16 glider on 8/20/2010 overlaid upon the surface salinity forecast from the NYHOPs model.  NYHOPs indicated that we launched the robot on the estuarine plume front which is why we may have had some buoyancy issues with the glider.

Launching the "bird" from the Research Vessel "The Torch".  Highlands New Jersey is in the back round on the right.

The "bird" at the surface.  The glider has a satellite telephone in its tail so the COOL room can upload instructions and download data to the robot anywhere in the world.

The pod of porpoises we saw on the way home about 1/2 mile off Sandy Hook.

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