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Journals 2005/2006

Christine Leavor
Seneca Elementary, Salamanca, New York

"Water Quality in Rhode Island Coastal Waters"
R/V Cap'n Bert
August 8 - 19, 2005
Journal Index:
August 8 - 9 - 10 - 11 - 12 - 13/14 - 15
           16 - 17 - 18 - 19

August 12, 2005
Dissolved Oxygen Samples

We met at the dock, coffee in hand, and launched right away. In fact, we made it to station 6 by 8:45.

Today's routine was pretty much the same, with one difference. Today we also collected samples for dissolved oxygen testing. At each site a Niskin bottle was dropped to collect samples from both the surface and bottom of the Bay. A Niskin bottle is a tank that is open on both ends to allow it to drop through the water column. At the desired depth, a weight is dropped down a wire and it drops on the bottle closing it. The bottle is then lifted and drained into glass collection bottles.

We collected 8 bottles each from both the surface and bottom. I held the Niskin while Kelly filled the bottles and carefully put a glass stopper in each. She had to be sure there was no air bubbles in the samples.

Niskin Bottle. View full version pop-up.   Niskin different angle. View full version pop-up.   Attaching bottle to cable. View full version pop-up.

Then four of the samples were "fixed" by adding drops of Magnesium chloride and Alkaline Iodide. This fixed the dissolved oxygen. The other four were placed in cool water and kept in the dark. Time is important, and they will need to be tested at very precise times- 24 hours from collection. The oxygen in the unfixed bottles will be compared to the fixed ones and the difference will be an indication of the amount of respiration taking place in the samples over a 24-hour period.

Another difference in today's routine was that when Kelly filtered for the chlorophyll samples, she also filtered another sample, which will be tested for organic particulates.

Today I also got to help launch the Acrobat for the tow back. I held a long cable that was attached to the machine, and when Dave gave me the nod, I yanked really hard and that released the machine in the water.

When we got back to dock today, we had to tear down all the equipment and load it all up to be taken back to the University. We won't be going back out until Wednesday, when the whole procedure will begin again. I also noted that I wasn't as tired today as I was Wednesday.