27.01.2013 (Sunday). ...00:00-03:00
: we sort the sample of the second Agassiz in our dry lab (no time for the
material of the Rauschert dredge which is stored in a cooled container). Most
specimens are photographed with my new camera Nikon D5100 combined with a Sigma
150 mm objective mounted on a rail. Very powerful gear but I have problems for
getting enough depth field. Specimens are then fixed either in absolute or in
95% alcohol and put in the freezer at -20°C. At the end, we are both completely
exhausted. I sleep until 10:00. Morning: weather cloudy. The sea remains very
calm. Examination of the GOPRO videos from yesterday: very disappointing. All
images are taken with a fish eye effect, which can apparently not be removed.
Most sequences are just good for the bin. Agassiz trawl at the North of
Joinville around 15:00, deeper than yesterday: around 450 m depth. A lot of
serolid isopods (even bigger species than those from Patagonia): Ceratoserolis group trilobitoides (up to 60 mm long! -
some with eggs in their brooding pouch) and two Serolis bouvieri (about 35 mm); some scavenging isopods of the
genus Natatolana; many shrimps
(mostly Notocrangon antarctictus
mixed with some Chorismus antarcticus);
some Antarctomysis (bigger than
yesterday); not many amphipods (e.g. big Eusirus
spp.). Rauschert dredge at 17:30 (a little bit of snow); bag of net not
tied properly and we lost a part of the catch. Still interesting species like Parepimeria major. After sorting the
remaining muddy gravel, we take the sample of the dredge of yesterday (as said
earlier, we had no time for that yesterday and had to put it in a cooled
container). Most animals are already dead despite they were put in a cooled
room (probably the traumatism resulting from their capture). Work finished at
23:30. Around midnight, I hear strange noise. I look by the window: the ship
enters into the ice...
Sample from the Agassiz trawl as it arrived on deck.
Marie working on deck
Ceratoserolis group trilobitoides. We got a lot of specimens from that species. Some were about 60 mm long. There are two or three very similar species in the area and i cannot identify them on board with the literature at hand.
The pink disk is the ventral brood pouch full of eggs of a big female of Ceratoserolis group trilobitoides.
Serolis bouvieri is a less abundant and rather different species of Antarctic serolid. It is about 40 mm long.
The Rauschert dredge is a smaal gear (a bit more than 50 cm wide), which is very efficient for collecting small crustaceans in Antarctic seas.
Parepimeria major: a rather uncommon Antarctic amphipod collected in our dredge.
Rhachotropis antarctica is a very common Antarctic amphipod. However it is very fragile and usually we only get badly mutilated specimens. The legs of this one are nearly intact.
(Cédric)
Still in Joinville North, we are going
to sample at a deeper station, around 430 m. The Agassiz catch is not as
impressive as the second one of yesterday. When the subsample is withdrawn, we
look in the mud for big amphipods but I can only find a few. We sieve some of
the mud, but there’s not much more in it. The Raushert Dredge opened on one
side, so we probably lost part of the catch. As a result, the samples obtained
are not very abundant as well. A lot of tiny amphipods, but not many Epimerids
and Iphimedids. We finish to sort out this catch around 23h. We then gather in
the red saloon with some other students and suddenly hear a roaring sound like
thunder and the boat is trembling. The ship is going through the ice! We head
outside to look at the spectacular sight of the ice breaking under the power of
the boat, passing under it and then projected on the sides. The ice is pale
blue underneath, sometimes brown from the sympagic algae, quite thick. During
the night, I wake up from time to time because of the sound and the trembling
from the ice-breaking.
Hauling the dredge
(Marie)
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