27.02.2013 (Wednesday). My clock was supposed to ring at 07:00.
Apparently it did but I did not hear it. At 07:25 I emerge from the sleep as
Marc Eléaume puts the light on in our cabin. I get up with difficulties. We
have the time to take our breakfast and we go out. Weather ouside: open sky,
not cold, some waves but not high. The Agassiz trawl is up around 08:25.
Content dominated by sponges. Also small stones, hydrocorals and crinoids. The
sea-urchins people are happy because they get enough of their spiny
friends/victims for their physiological studies. We do not get so many
amphipods, but some interesting like Echiniphimedia
gabrielae and the 'slender spines' form of Echiniphimedia hodgsoni. We suspect that the form with slender projections
and that with robust projections are two different species but we never had the
opportunity to test if they are indeed genetically different. If so, one should
be one more on the list of our undescribed species to describe.
Echiniphimedia complex hodgsoni, species/form with slender projections/spines.
Our traps put at sea yesterday are supposed to be relased from the
bottom at 12:45. However we are in advance on schedule. I am asked by the crew
to release them from the sea floor around 12:15. I rush outside with the
telecommand. I deploy the cable of the hydrophone, connect it to the
telecommand. I send the message of release to the acoustic larger. No reply
message! Oh ghosh, what's happen? The reason is simple: the hydrophone has not
been put in the water and in my excitation, I did not realized that! We put it
in the water. I load again the telecommand. A few second later I send the
release message. Two VERY long seconds and the telecommand makes a bip. The bip
means that the lander has been released. Good! It comes up at a speed of about
1m/s. The depth is 180 m. The conditions of visibility are excellent. About 6
minutes later the lander is seen at the surface, on starboard, ahead of the the
ship. Some ropes of the system are grasped by a hook and fixed to a side crane
of thye ship. The lander is hauled up and put on board. One strange thing: the
flag pole has collapsed and is now twisted as a huge spaghetti. How is this
possible? Careful examination reveals that the flagpole was not a metal stick
with a light plastic sheath as I thought but was entirely in plastic... Marie,
who did not realize that the releasing operation happened in advance of the
time schedule, does arrive. Once again, she will see the operation on video. We
remove the traps from their fixation system. we release their content in
plastic buckets full of cold sea water: hundreds of amphipods and isopods. The
bait was not fresh and we left the traps in water for 24h instead of 48h
(optimal duration according to empirical observations). I was expecting
thousands. Anyway, the main point is not the quantity but the quality. We will
see. I first have to get rid of the bait from the bait boxes: plastic boxes of
8 cm with small holes allowing the smell to spread out but limiting the
possibility of consumption, ...at least for large and mid-sized specimens. Some
small hungry crustaceans managed to get inside the bait boxes anyway. There is
even a small isopod passing its head through one of these tiny hole and looking at us with a comic
expression. I will not look for those guys, who entered the boxes: I throw away
all the stinky half rotten fishes and the gourmets feeding on them. We will
have enough work with the rest.
In the wet lab, we put all the scavenging crustaceans from the trap
in a white tray with cold seawater. They will mostly concern Charlotte
Havermans from our museum (amphipods) and Christoph Held of the AWI (isopods).
We carry out the pre-sorting. First we take out the isopods (Natatolana spp.), then we look for
amphipods (all from the superfamily Lysianassoidea except a single Oradarea sp.) and separate them in five
categories distinguishable by the naked eye. The representatives of these
categories are in fairly similar proportions: a large species with white eyes (Parschisturella carinata), a large
species with elongated red eyes (Tryphosella
murrayi), a medium-sized specieswith non-elongated red eyes (Hippomedon sp.), a small compact species
(Orchomenella pinguides), a large
dark-eyed form (provisionnally
identified as Pseudorchomene plebs).
We go to our dry lab with the specimens. I realize that, when I
made pictures and videos of the recuperation of the traps, I kept the setting
of my camera for the macrophotography of specimens: all my pictures are
strongly overexposed and could be uploaded on this blog only after a delicate
Photoshop therapy. I will try to not repeat this mistake the next time.
We look at the specimens, make photographs and put them in properly
labelled vials with absolute alcohol (best fixation for DNA studies. Under magnifying
lenses, I detect a few specimen of an additional species with red and white
L-shaped eyes referred as Tryphosella group macropareia. Then a big surprise. I was already starting to fix what I believed to be a
pure sample of Pseudorchomene plebs,
i.e. by far the most abundantly amphipod collected in baited traps in
Antarctica. Then my eyes are catched by the unusual tinge of the eye of one
specimen. I look at it under the dissecting microscope. Its eye is
silver-coloured instead of being dark brownish red as in P. plebs. Furthermore the dorsal process of its first urosomite is
slightly more angular than in P. plebs
(something that only a trained or very careful eye can perceive). I take a good
series of specimens and look at them one by one under the dissecting microscope.
The specimens can clearly be separated into two categories by the eye colour
and to a lesser extent by the shape of the first urosomite. There are actually a lot of specimen of that sliver-eyed species. Due to lack of time,
I cannot identify them immediately, but on March 7th, I looked again to them and I identify them as Abyssorchomene charcoti.
At 22:15, the fog has fallen on the sea.
(Cédric)
27.02.2013 (Wednesday). We wake up at 7 am for the Agassiz trawl. Outside, the sky is completely clear of
clouds and the moon is full. It’s still a bit dark but the sun will soon go up.
I find it very unusual to see the moon so clearly with so much daylight
already. In the far, the Antarctic Peninsula
appears progressively as the light increases. It’s like an irregularly shaped
shadow in the horizon. We can even see the shadow of a ship in front of it,
apparently a fishery boat. The sky turns pink above this piece of land, which
makes the whole scenery very surrealistic. It was worth getting up so early,
also for the catch. The trawl brought up a lot of organisms of all sorts, very
clean, and everyone got some interesting material. Less amphipods than
expected, but with the material we already gathered this week, we can´t
complain. We don´t have time in the schedule for a dredge, but today we have to
recover the traps. I am quite exited about that, it´s something new for me and
always a surprise to see if it worked well. The cage wasn´t hard to find back
and was brought on board without any problems. We can soon see a lot of tiny
animals moving in a remaining layer of water at the bottom of each trap. The catch
was successful, the quantity of animals can apparently be higher, even though
it seemed already a lot to me, but the diversity of species was quite good. It
entirely consists of necrophagous amphipods and isopods, as we put pieces of
dead fish in the traps. The amphipods all belong to the super-family
Lysianassoidea, although it can happen that other kinds of amphis get trapped
“by mistake”. The ZDF team was there to take pictures and film the recovery of
the traps and the processing of the catch, as it´s a gear that we don´t deploy
so often. We´ll maybe deploy it 3 or 4 times tops on the whole trip.
Afterwards, we separate the different species in the wet lab. It takes a lot of
time because there are so many animals and we have to pick them up one by one.
Then, we fix them in ethanol for molecular studies.
(Marie)
The lander has come back to the surface.
Sorting samples from the traps.
Tray with hundreds of amphipods coming from the six traps put on the lander. You can se the reflection of the light that we use for a better preliminary sorting of species and categories. During the preliminary sorting, we pay a special attention to the shape and the colour of the eyes of the amphipods. This requires sharp eyes. After that an examination under the dissecting microscope is usually necessary.
Pseudorchomene plebs usually comes in crowds into the traps.
This time, Abyssorchomene charcoti was also found in large number in the traps. Its silver/gray eyes allow easy recognition under the microscope, but not with the naked eyes.
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