Thursday, December 1, 2011

Moving south with the ice

We have now bid farewell to the Chukchi Sea and are in the northern Bering, working north of Saint Lawrence Island.  Most fantastically, the ice is coming with us!  Winds have been from the north, bringing cold air south and also blowing the ice south so that we are still in ice.  Right now the ship is rumbling and bouncing up and down as she cuts through the ice.  The ice consists of pancakes cemented together with new ice.  In the image from the “aloft con”, or “happy”, camera the ice is clearly visible in the flood and ice lights from the ship.  We are heading to a station to the east of St. Lawrence Island and should arrive there at around 11 PM.

View of the bow of the ship and new ice in the flood and ice lights from the "happy cam"
Yesterday we worked across Bering Strait.  We arrived at our first station as the sun was rising and lightening the sky, although we never actually saw the sun (too cloudy).   Note also that we were there at about noon, showing how late in the day the sun actually rises here.  We had a beautiful view of the Diomede Islands that are located in the center of Bering Strait, with Little Diomede on the US side and Big Diomede on the Russian Side.  Little Diomede also is the home to a small community of about 100 people that clings to the southern tip of the rocky island.  

Little Diomede Island viewed across the new ice from our sampling location.

Today we sampled to the south of Bering Strait along the US-Russian border.  Here we caught a fantastic number of krill!  Bob, Celia, Donna, Kristina, Joel, Phil, and Chantelle all worked to sort out the krill and some Calanus copepods and set up a grazing experiment to see how much and what the animals are eating.  So as I am writing this the experimental bottles are on the plankton wheel in the cold room, rotating slowly to keep the food in suspension and available to be filtered out by the small crustaceans.
Dish of krill viewed through a microscope. 

What are these animals going to eat, one might ask, in the dark and cold of early winter here in the Bering Sea?  Well, there are low numbers of phytoplankton present as seen in the low quantity of chlorophyll or plant pigment in the water (measured by Dean and also by the fluorometers on the CTD rosette and in the system that measures temperature, salinity, and fluorescence constantly from the seawater) and seen by Sam in his system that photographs phytoplankton to see what types and how many of each type are present.   So the crustaceans might be eating the scant phytoplankton.  We expect also that there are smaller zooplankton, or microzooplankton, present that the larger copepods and krill can feed upon.  After we do our experiments, we will count the numbers of microzooplankton in the bottles to see if the copepods and krill have been eating them. 
Sam and Dean watch the computer screen as Sam’s instrument catches images of phytoplankton from a sample.  Sam and Dean both study phytoplankton.

An example of a phytoplankton image from Sam’s instrument.

As we have moved south, the sun has risen again and now remains above the horizon for a few hours.  A few weeks ago we entered the dark of Arctic winter; now we have emerged from that darkness and are once again enjoying the light.

View of sea ice with sun today.         
The CTD and rosette enters the water near some recently broken ice.

1 comment:

  1. Am surprised to see the ice cover so far south. Thanks for the post and pics and we are looking forward to more. Be safe.