7 Aug 2012
CCE LTER Cruise: Day 10, Ahoy E- Front
Written by Dana Lebental, Teacher at Sea
August 6- Day 10
After 10 days of being at sea a lot has happened. And, we found the front!!
This front is where the California Current meets the inshore currents. We have named this particular front “E front” as in eddy front, since it looks like an eddy (possibly two eddies) from the satellite pictures we are getting from NASA.
So now we verify the location by staying up ALL night collecting samples. The sampling started at noon and did not end until noon the next day. It was a long 24 hours. And, no we didn’t do all our work in or by the hot tub!
The samples had to be done at night so we could ensure that the zooplankton was present at the sampling depth (remember they migrate up and down in the water column). So almost every hour on the hour we gently lowered a Bongo Net into the water 300 ft, waited 30 seconds, then gently brought it up. All the water would flow through the net leaving the zooplankton from the light zone of the ocean, also known as the epipelagic zone , to be caught in the net.
When the nets were retrieved we placed the samples in bottles. Based on the picture below of the zooplankton retrieved from the bongo nets, can you tell where the front is?
Another type of sampling we did was lowering the CTD (Conductivity, Temperature and Depth instrument, which looks like a cage with plastic bottles in the middle) into the ocean down to 900 ft. Now the CTD can open bottles at different depths to collect samples. Last night I helped in the chlorophyll lab, so we needed to fill 4 bottles with water from each of the 8-sampling depths. Once the water was obtained, we then went inside to filter the water, which consisted of pouring each bottle of water through a different type or size of filter paper, then collecting the paper, preserving the filter paper in acetone and freezing it. This needed to be completed before the next station. So we were working feverishly.
By the end of the night we had successful completed 13 CTD, Trace Metal CTD and Bong Net cycles. This was my one last look before going to bed 🙂