South Atlantic cruise on "RV Akademik Ioffe" 2009
Author: Dr. Angel Perez Day 15-16
November 8-9, 2009
We are in our second day of continuous steaming after Superstation 4. Wind force has increased considerably reaching 20 knots this morning, as we entered the Ascension Island EEZ. Waves are 1,5 - 2 m high which doesn't seem to affect the Ak Ioffe's stability or our life on board except for the whale watching activity that becomes more difficult. We have devoted our time to species identification and feeding the MAR-ECO data bank. That will help scientists to begin analysing diversity data shortly after our return. So far we have inserted 178 samples of 114 especies including fish, cephalopods, corals, holothurians, urchins, crustaceans, sponges e other animals. We have reached 2,213 individual records in the data bank, and there still more to enter.
November 10-11, 2009
The fish group decided to make extra short nocturnal trawls with the IKMT net during our route to Superstation 5. The first one took place in the first hours of tuesday November 11th, just as we finally moved out of Ascension Island EEZ. The second, occurred on following evening over the Mid-Atlantic Ridge approximately at 16oS. Both of them were aimed at sampling the scattering layer that was very thin and normally divided in a deep branch, at 200-300m, and a shallow branch, at 20 - 30m depth. Catches were poor when compared to the ones obtained at the equatorial area, but still a considerable diversity of mesopelagic fish and squid was recorded.
November 12, 2009
We arrived at Superstation 5 around 11:00hs today and started by conducting a CTD cast 2500 m deep. We were also able to collect water samples at 2000, 1000 and 500 m depths to be used for microbiological studies. Plankton sampling followed immediately with the WP2 net being hawled vertically from 1000 m depth to the surface. That procedure produced a very poor sample and there was a general feeling that we had definetely entered the tropical oligotrophic (nutrient-poor) waters. That feeling was confirmed in the following pelagic trawls which produced a very modest catch of macrozooplankton, fish and cephalopod. The first of the two trawls, however, went down to 2,200m depth and captured some interesting bathypelagic forms such as the viper fish (Chauliodus sloani), gulper eel (Eurypharynx pelecanoides) and a young Ctenopteryx sicula, a squid that has fleshy fins that surround the mantle. Searching for flat seafloor to opperate the sigsbee trawl was again not an easy task.
The benthos group decided for a depression observed among seamount summits, around 3700 m deep, hoping that sediment layers would be accumulated on it. After a four hour opperation the trawl was finally brought to the surface containing several vulcanic rocks, mostly manganese crusts, but no soft sediments. Catch was poor and mostly composed of sponges. Superstation 5 completed, we started to steam immediately to Superstation 6, only 15 miles away.
November 13, 2009
Superstation 6 started at 1:00h of this friday 13th, this time with the operation of the IKMT net in two consecutive trawls, the first one reaching 2000 m deep mesopelagic layer. It is not known whether any of us were superstitious at all, but the events thereafter were no doubt strange, to say the least. The best description of them was provided by Kat Bolstad:
"What Luck” by Kat Bolstad
Every morning (well, those when we aren’t still in the lab at daybreak), we are awakened by an announcement at 7am. Today, it went like this: ‘Good morning, everybody. Ship’s time is seven o’clock. Today is Friday, the 13th of November. We are still drifting at the station.’Two things about this announcement struck me, although I didn’t think them related at the time. First, it’s Friday the 13th. Second, we should have had two nekton samples, starting around 4am, and the station should have been finished by now. Yet here I was, still happily in bed.It turned out there may have been a connection after all, at least to anyone of a superstitious nature. While reeling in the first nekton trawl, just as the catch was being lifted from the water, the cable holding the net snapped – literally, twang, ends flying and crew on deck ducking for cover. This could have been completely disastrous, but by extreme luck, it wasn’t – no one was injured, and what’s more, the net wasn’t lost. The seaward end of the snapped cable wrapped itself twice around the top of the gantry used to deploy and retrieve the net, securing itself in place in just about the most unlikely way possible. So the net dangled, but in relative security, until an additional cable could be secured to reel it in. (This was all related to me over breakfast, just before I spilled my cup of tea over most of the table – I’d like to say that that was also abnormal bad luck, but I should probably just confess that I’m not the most coordinated person in the morning.)When the catch was finally brought in, we weren’t sure what it would hold, and what condition it would be in after all the morning’s drama and delay. But we should have predicted that if there was one day of this cruise destined to bring in Vampyroteuthis infernalis, the vampire squid, Friday the 13th would be it. And not one, but two specimens – both small (mantles about the size of a walnut and an almond), but in quite good condition, relatively. Vampyroteuthis is an ancient order of cephalopods, with a very gelatinous body and thin, delicate skin that ranges in colour from brick red to deep purple-black. It looks like a small octopus, with eight short arms and a deep web, but it also has paddle-shaped fins and two photophores (light organs) at the end of the mantle, and two tentacle-like sensory filaments that retract into pouches near the first (dorsal) pair of arms. Our larger specimen was in better shape, although its mantle was inside out (we gently rectified this before fixing it in formalin). The oral face of its arms and web were deep, solid, inky black and the tiny finger-like cirri on the arms could still be seen. The eyes were perfect and some shreds of delicate skin still clung to the mantle and fins, and both photophores were present. Although Vampyroteuthis is not terribly rare in the oceans, specimens of it are rare, especially in decent condition, so today we consider ourselves lucky indeed."Lucky or not, Superstation 6 was basically finished right in its first sampling activity. Before breakfast, however, we still were able to conduct plankton sampling with the WP2 net that has been deployed by a different winch and therefore not affect by the unfortunate events. After that some of us could finally go to bed, while the Ak Ioffe started her route to SE, towards the Angola Abyssal Plain and away, at last, from the Mid Atlantic Ridge. We hope to be back in the future, hopefully with more time, sampling opportunities and "luck".
November 14, 2009
Author: Dr. Angel Perez
The day today was devoted to repair the wire of the main winch as to allow us to continue with our sampling programme in the fore coming Superstations at the Walvis Ridge. It was concluded that there were several fragile sections in the wire that needed replacement and thus the day started with nearly 1 km of wire been released into the sea in order to reach these damaged sections previously rolled in the which's drum. While one end of the wire was free at sea, onboard the wire was tied to the stern and cut apart from the drum's "bad" wire. This was discarded to the sea (~1 km) and then the harsh and tedious mending work begun. First the "good" wire still in the drum was merged with the segment that was hanging from the ships stern. Then a brand new 1.5km wire was added to the end of the restored one. This work lasted the entire day and was done by very skilled members of the crew with help of some scientists. As the sun set today the winch drum was already loaded with continuous and hopefully strong 6 km of steel wire, ready for the remaining of this first South Atlantic MAR-ECO cruise. The benthos group had planned an abyssal trawl in the next days. It will be a chance to test it. See also special reports from the pelagic sampling (by Stas Kobyliansky, Shirshov Institute of Oceanology) and benthic sampling (by Andrey Gebruk, Shirshov Institute of Oceanology)