Apr 10 - KEP, BI and on to the WCB
This week on the JCR
When you left us last time it was 31st March and we were just about ready to kick off the coring to the north-east of South Georgia with Team Mud. After an evening of surveying in the area, work on deck started at first light, with the piston corer being in the water and on the way down to the seafloor by 0600. The whole process took about 3 hours, a 9-metre core of sediment on deck by 0845. After transferring to a second site the process was to be repeated exactly, with a second 9-metre core back on deck, ready for processing before dark. The plan for the next 24 hours of work was to mirror the previous day and, after another night of surveying, the morning was to heralded by a third core of identical length. Team mud already had 3 very good cored at this site but the 4th and final one was just not to be quite as successful. The sediment at the afternoon site was sandier than expected from the surveying and was just too much for the piston corer on board. The coring had though succeeded in obtaining many thousands of years of sediment, to be analysed over the coming years back in Cambridge.
Overnight it was thus on down to Cumberland Bay and the BAS station at King Edward Point, the ship arriving at the jetty at 0830, with a full Monkey Island admiring the view. The plan here at KEP was to undertake 2 days of diving, collecting samples for Kieran's project here on the JCR, (to be explained in full next week) as has been undertaken at various sites throughout our journey around the Scotia Arc. There were 3 dives planned for 3rd April, with the humbers being in the water by just an hour after the JCR's arrival, ready to check for any Leopard Seals present in the area prior to diving. While the diving was taking place the coring equipment, no longer needed, was demobilized and fully stored away, ready for the ship's passage back to the UK. Those not involved in either the diving or the deck work had the opportunity to stretch their legs properly for the first time since being at Jubany several weeks previously.
In the evening all those on board not on duty were invited to a barbecue in the Boatshed at KEP, many catching up with old friends they had not seen for a long, long time. After an ever-so-pleasant evening, work was, as usual, to start again in earnest first thing, with the Humbers back in the water by 0800. Two dives were undertaken to collect the final required specimens and the boats were re-stowed on deck by lunchtime. The ship left the jetty to a farewell from all the winterers left on base at 1600, allowing many on board to witness a beautiful sunset over Cumberland Bay, just as the weather could be seen drawing in ahead of us.
The starting point for the 5th April was to be at Bird Island. The JCR was on DP off Morris Point at 0700, and soon after, two of the ships humbers headed into base with a small quantity of supplies. Four members of the base were to be picked up, leaving the final four alone for about the next seven months. Two of those coming off the island had been there over this last summer, while the other two, Isaac and Sarah, were leaving what had been their home for the last two and a half years. It was to be a true whistle stop visit, with the humbers being tied up at the jetty for only 12 minutes before waving goodbye to the four still left behind.
This quick sortie into Bird Island was to give a few of the science staff a lie in, before what would be a long day's work. The JCR was on station for first of the two Western Core Box moorings by 0945. A CTD was undertaken prior to the recovery of the shallow mooring and the process was then repeated in deeper water. Both moorings were recovered successfully and the ship was heading off to the next BIOPEARL transect station at 1430. The weather forcast was for things to continue to deteriorate, with strong winds expected by early the next morning. The decision had thus been made to work through the night at as many of the 4 stations possible until it was no longer safe. The last trawl was on deck and being sorted at around dawn, to the most stunning of backdrops, with the last item of work being the 1500m CTD which was back on deck at 0730.
The wind had whipped up and the swell continued to increase, making any more work, as predicted, unfeasible and so the ship was hove-to, into the wind and swell, waiting for things to abate. The next day was due to be the the start of the Western Core Box (for the 3rd time this season) but the rough weather continued and the JCR therefore remained hove-to for a second day. The WCB would have to wait for the moment, at least until the next morning (7th April).
But for that you will have to wait until next week.
And now for the Science bit
this week with Jan Strugnell
JR147 is a small octopus-catching component of the cruise comprising two ½ days of fishing around Elephant and Signy Islands. Otter trawls were used to catch octopus due to the fact that they sample a relatively large area in comparison with the Agassiz trawl and are thus more effective at catching octopus. Furthermore, otter trawls can be trawled relatively quickly (~4 knots) which is essential to catch octopus as they are good swimmers and are capable of swimming out of the net.
The project I am working on is using octopuses to test the hypothesis that the Antarctic has acted as a centre for evolutionary innovation and as a source of taxa that have invaded the deep sea. In the past the deep sea has been subjected to massive extinction events due to having very low levels of oxygen. These extinction events were very severe and it is unlikely that many organisms were able to maintain survival in the deep sea during this time. The subsequent development of deep water connections between the Southern Ocean and the major oceans which surround it would have provided oxygen rich waters to return to the deep sea and was possibly a source of octopus to recolonise the deep sea.
There are 3 groups of octopus that are endemic to Antarctica, Pareledone, Adelieledone and Megaleledone. Studies have shown these octopus groups to be closely related to one another, and to also have close relatives in the deep sea. Unravelling relationships between the Antarctic and deep sea octopus taxa will provide insights into their evolutionary history and will help determine if Antarctic octopuses did infact invade the deep sea. I will examine the relationships between these octopus groups using DNA sequences from representatives from each of these genera.
The second aim of the project is characterise micro-evolutionary processes of 3 octopus species found only in Antarctic waters; (Adelieledone polymorpha, Pareledone turqueti, Pareledone charcoti). Genetic diversity and population structure will be characterised for these octopus and this will provide information on the mechanisms and capability of dispersal of octopus. 50 individuals of each of the three species from both sites were targeted for this component of the project.
So far Iíve managed to catch 295 octopus individuals, 200 of which were from Elephant Island which seems to be a bit of an octopus hotspot! Iíve caught at least 7 species of octopus so far, but probably more. Further work identifying and processing these octopus will continue back at BAS, Cambridge, and Queenís University, Belfast.
Jan with two different Megaleledone Octopuses
And now for a few more of Jan's Beasties
Above Pictures all from Jan Strugnell
And again here are a few more of the Scientists and Crew
A brief and somewhat potted history of South Georgia
by Mike Gloistein.
South Georgia lies at approximately 54° South and is about 170 km long and ranges in width between 2 and 30 km. The island is spectacular in that it consists of a large number of snow-capped mountains and has been described as 'the Alps in mid-ocean' and is in fact the summit of a partly drowned mountain range. There are two principal mountain ranges, the Allardyce and Salvesen. The highest peak is that of Mount Paget at 2934 m and there are twelve further peaks of more than 2000m.
South Georgia was probably discovered by Antoine de la Rochéé who sighted it in 1675 whilst on passage from South America to France. The next recorded sighting was in 1756 by Gregorio Jerez on board the Leóón. It was in 1775 that Captain James Cook arrived and on 14 January one of his midshipmen, Thomas Willis, saw land which was eventually named after him (The Willis Islands at the western end of South Georgia) and named the land in honour of His Majesty King George as Isle of Georgia. As part of his report on the island, Captain Cook made mention of the large numbers of elephant and fur seals and this soon came to the attention of the sealing industry and so started what was to become a somewhat bloody period in the history of South Georgia. Due to the very secretive nature of sealers, many records of the earliest activities are not known, however there are some references that date back to 1786. One vessel, Aspasia, collected some 57,000 fur seal skins in 1800/1801 and whilst this was a large number for a single ship it does give some idea of the slaughter that took place on the island. Sealing would continue, in several waves, for the next 100 years and in 1881 there were regulations put into place to control and protect the seals by giving a closed season between 1 October and 1 April.
The first whaling station was established in King Edward Cove in 1904 and between then and 1965 South Georgia was one of the most important places in the world for the whaling industry. There were whaling stations in seven harbours on the island and during the period some thirteen floating factories were also used. In 1965 the whaling stations were abandoned and whilst at Grytviken a caretaker was employed until 1971, the stations were never reopened and have now become derelict reminders to the past. During the period 1904 to 1965 a total of 175,200 whales were taken at South Georgia compared with 1,432,862 recorded as being taken from Antarctica between 1904 and 1978.
Captain Cook showed little imagination in naming a small island off the western end of South Georgia, Bird Island as, even then, the surrounding sky would have been filled with bird life as it is today. Cold water, rich in nutrients comes to the surface (upwells) near Bird Island supporting a rich marine life on which both birds and seals can feed. Not suprisingly BAS have had a research station on Bird Island since the early 1970s and in recent years the station has been operated year round with 3-4 personnel overwintering. The seal and bird research undertaken there has rightly acquired an enormous international reputation. The island is home to most of world's largest albatross, the wandering albatross, but also to black-browed, light mantled sooty and grey headed species. Numerous other smaller birds and an enormous colony of Macaroni penguins nest on Bird Island. On the beaches around the station thousands of fur seals come ashore each year to give birth and immediately start the breeding cycle again !! Ferocious fights between bull seals over the ownership of harems of females give a real impression of a battlefield early in the season. Later in the season the cove in front of the station fills with hundreds of seal pups which provide huge entertainment to those working there.
And that's it for the moment but we will see you all next week.