Jubany to the South Orkneys
So let me see? Where were we when you left us last week? Oh yes! We had just arrived outside Potter Cove, where the Argentinean base of Jubany is situated. Weather had been particularly rough on our passage from the last trawling site and we had been forced to sit on DP outside the cove overnight as it would have been unsafe to send any of the Humbers into shore that evening. Fortunately, though, the wind died down overnight and the sea state calmed. The engine room was ready on standby at 0700 and by 0730 the ship was already at anchor in the cove, in full view of the base itself. The main aim of this leg of the journey was to collect inshore samples of a number of species using the dive team. (the specifics of the project will be explained next week) The Argentinean base has it's own diving facilities so the plan was to first send one of the Humbers ashore to gain some local knowledge of the best locations for collection of the required species. Three of the six-strong dive team were on base by 0830, while the others were on the ship preparing equipment for the first dive. Whilst at base, arrangements were made for a group of 20 guests to come over to the ship for lunch the next day, and subsequently to allow those that were free on the ship to be shown around the base.
After the team had returned to the ship two days diving and fishing commenced. The first set of divers were in the water by 1030, and a total of 3 dives were undertaken during the day. Over lunch the Cargo Tender was launched and the Fish Team deployed three Trammel Nets at separate sites around Potter Cove.
The 9th of March was to be a busy day for all on board, with two of the ship's three Humbers and the Cargo Tender being launched first thing. Two more dives were to be undertaken in the morning while the Cargo tender recovered all the Trammel Nets, which had, overnight, been highly successful. The fish team worked on the aft deck sorting the catch through the afternoon and then took DNA samples until late into the night. At 1200 the Cargo Tender went into base to pick up our guests. A buffet was laid out in the Officers Lounge, and the guests taken on a tour around the ship by the science staff on board. After 1400 the favour was to be returned, and those without on-board commitments were given the opportunity to visit and be shown around the Argentinean Base Jubany.
Due to the need for a steady ship to allow work to be undertaken on the collected samples (see next week) the ship stayed at anchor overnight, heading back out into open water on Fri 10th. These next few days were devoted to the Fish and Octopus Teams, both of them using the Otter Trawl for collection of their specimens. The 10th, though, was unfortunately just not to be. It was essential to find a flat-bottomed portion of the seabed that would be safe to trawl, but unfortunately it wasn't until late in the evening that an appropriate site was pin-pointed. Trawling commenced at first light the next day and continued until around lunchtime.
The ship then set off to the North-east in the direction of Elephant Island where of the Fish, Octopus and BIOPEARL teams would be trawling over the coming four days. Initially it was to be the turn of the BIOPEARL team, with the first CTD of their four-station transect started at 1630 11th march. Work continued until 2200, and resumed at 0600the next morning, with the whole transect completed by late on the evening of the 12th. Overnight the ship steamed to the west of Elephant Island, to another trawling site for the Fish and Octopus teams. The site was first surveyed to identify an area of seabed suitable for bottom-trawling, and the Otter trawl was deployed soon after 0600. Trawling was continued over the next couple of days, with great success, particularly with respect to Octopus specimens.
After an extra epibenthic sledge was undertaken in the evening of the 14th, the ship set course eastwards for the South Orkneys, where the next area of trawling was to be undertaken. First, though, was the turn of Mud Team. Claire and Anna were planning to take cores of sediment from an area of deep water called the Hesperides Trough between South Shetlands and South Orkneys using a piece of equipment known as a Piston Corer. Over the coming 24 hours they surveyed the sediment on the seabed of this region before undertaking a couple of cores, both of which were highly successful, in a water-depth of about 2500m. The two 10-metre core samples will be examined for microscopic organisms over the coming years back in Cambridge. You can read more about the specifics of their mud in a couple of weeks.
On completion of the coring in the area of Hesperides Trough, the JCR continued her eastward progress towards the South Orkneys. Here there would be more sea floor sampling with the BIOPEARL team, Trammel Netting, trawling for fish and octopus, diving and hopefully a visit into Signy Island itself. For that, we will just have to wait and see how the weather fares and for yourselves, you will have to wait another week.
And now for some of the Science Stuff
This week with Huw Griffiths
The largest project being run on this cruise is benthic sampling (collecting organisms from the bottom of the sea) as part of the BAS project BIOPEARL. We are looking at seven different locations and are taking samples from different depths at each place (1500m, 1000m, 500m and 200m deep). We are using three types of equipment to look at different biological and environmental factors. We use a device known as a CTD (Conductivity, Temperature, Depth gauge) to measure the temperature and salinity of the water. We use two types of fishing gear to sample the animal life. The first is the ‘Epibenthic sledge’, a type of net which slides along the sea floor collecting the very small animals which float just above it. Secondly we use a benthic Agassiz trawl, a bigger net which drags along the bottom scooping up most of the larger creatures in its path e.g. starfish and sea urchins.
The samples we collect are sorted into the different types of animals and if possible identified to species level. As much information as possible, such as total numbers and weights of each species, is recorded in a database so we can compare our catches from the different sites. One of the main aims of this project is to look for patterns in biodiversity in this region. Many of the samples will be used later for DNA analysis to show the genetic diversity and to help identify species. This work will provide a vital contribution to the Antarctic component of the “Barcode of life” project, which aims to gather information on the genetics of every species on the planet. Some animals, such as brittle stars, will be looked at in greater detail to see how the way in which they grow is affected by living in this unique environment.
Now some of the this week's samples
Pictures by Dave Barnes
And finally again for some of the glorious scientists and crew
More from the James Clark Ross, with more beasties.......Oh and more science specimens.......next week.