25.02.2013 - Improving the efficiency of the dredge

25.02.2013 (Monday). I wake up at 10:00. Pallid sun shining on an open sea with scarce icebergs. Waves moderate. The door of our lab must remain open and it is more or less fixed open. I say more or less: it is grating on its hinges as the shipe rolls on the sea. This repetitive and irritating sound makes me nervy.  Yesterday I tried to fixed it with small plastic collars. This morning I found them broken. I put a stronger collar; I manage to reduce the noise but do notsucceed  to suppress it completely. 

The pictures of the OFOS underwater video camera seem promising.

 

The OFOS underwater camera.

The OFOS video camera directly transmits videos and pictures from the Antarctic sea floor at hundred meter depth.

When the Agassiz trawl comes up (station 197-4, Bransfield Strait East, upper slope), it appears that the net has once again twisted around the frame of the trawl. I do not dare to think what would have happened if the dredge would had been fixed with a cable to the frame... There is extremely little in the net and nothing relevant for us. Due to the failure of the operation, it is repeated (station 197-5). This time, the trawl properly works. It comes up with a huge amount of material, but a large part of it consists in stones of varius sizes. However there is also a lot of organisms. We get amphipods but less than we would have expected. Then we use the dredge on the same bottom. It comes with a huge amount of sediment and large organisms: the trick suggested by Henri robert for widening the opening of the dredge did work. We spend quite a lot of time on deck (with the much appreciated help of Ryan Driscoll) for sieving the sediment (black gravel mixed with sand and a little bit of mud. Already a lot of amphipods (and other organisms for various colleagues) are separated and we expect to find much more when we will look at the content of the gravel in the wet lab. We put all this material in a cooled container. At 17:40, we go to diner, as the work made us hungry.  The sorting of the trawl and especially dredge material take a lot of time because it is an exceptionnally good catch, both quantitavively and qualitively (especially for the dredge). We get several species not found until now during this cruise and some, which I have never seen or never seen alive. The cutest species found in the catch is a tiny (7 mm) and spiny species with a name almost impossible to pronounce: Acanthonotozomoides oatsesi. We works until 02:45 and go to bed at 03:00. The last specimens are not sorted out and put together  in a vial of alcohol.

(Cédric)

Take a breath before trying to pronounce the name of this tiny (7 mm) but cute amphipod: Acanthonotozomoides oatesi.

Monday 25.02.13

The Agassiz is deployed a bit after lunch-time. The first trial was unsuccessful because the net turned upside down and got caught in the metal frame, but when we deploy it again, the catch is the biggest we´ve ever had. The dredge is very successful too. The net is full of gravel and countless small amphipods, among which some small epimerids-iphimedids that we didn’t catch before, such as Iphimediella dominici and Epimeria grandirostris. Also 3 specimens of the very rare and very strange-looking Acanthonotozomopsis pushkini. 

(Marie)

 Iphimediella dominici (7 mm)

Again a tiny species with a very long name: Acanthonotozomopsis pushkini (5 mm)