Friday, July 6, 2012

Sean - Drogues and plankton tows!

Hey, my name is Sean Brown and I recently began attending Southwestern Oregon Community College with plans to become a marine observer.  The first week of my internship has already given me practice in data management, display, and taxonomic identification that will be very important skills as a marine observer.  The importance of coastal marine resources to humans throughout history and the relationship that we have with these resources today has inspired my interest in marine sciences, and I feel very lucky to be living in such close proximity to a diversity of marine habitats and in the presence of so many people who are enthusiastic about their studies or research. 
For my internship I will be working with Dr. Alan Shanks and PHD candidate Marley Jarvis, assisting in Marley’s research on the dispersal of larvae in the near shore and intertidal around Sunset Bay and the effects that local water currents and circulation may have on that dispersal.  Two local phenomena we will be working with specifically are ocean fronts and the processes of upwelling and downwelling.  An ocean front is defined as a “boundary between two distinct water masses”, where the movement of water on either sides of the boundary are in different directions, can be convergent or divergent, influence upwelling and downwelling, and can have differences in salinity, temperature, and density.  The complexity of fronts is fascinating, occurring on small and large scales, and on different time scales with some being short lived whiles others longer.
   To study the local fronts out of Sunset Bay we will be using a CTD (Conductivity, Temperature, Depth) to measure those three characteristics of the body of water between the front and the coast and the waters outside the front.  The data collected from the CTD can then be displayed as a contour plot, providing a cross-sectional view of the characteristics of that body of water.   Here is an example out of Sunset Bay, with depth in meters and temperature in Celsius.
    We will also be using “drogues” and doing plankton tows.  The drogues are best described as underwater kites that can be placed at different depths and attached to a buoy to track the water currents at different depths.  The plankton tows will be done by towing a small net along the front formation and at different depths.  Depending upon the characteristics of a front, suspended material, including plankton, can congregate along the front and often allow them to be identified visually, where a congregation of debris or foam, etc forms a line across the surface, or even a congregation of birds that are there to feed on the plankton suspended along the front.  I’m excited  to learn more about these processes and will try to explain them more in upcoming posts.   There will be more photos to come so you can get a better idea of what this equipment looks like as well as the beautiful coastline I get to spend my days at work.

1 comment:

  1. Hi Sean. Thanks for sharing your project. It sounds like things are off to a great start. I hear marine observing work is exciting and challenging work - although a constant supply of fresh seafood as a perk! Your work with the drogues is pretty high tech compared to some work I have done deploying large grapefruit and chasing them with kayaks. I look forward to hearing more as the summer progresses. Welcome to PRIME! Jude