Apr 17 - The Western Core Box and Shag Rocks
Well, when you last left us we were still hove to, awaiting to start the Western Core Box for the third time this season. Fortunately, the wind and swell did ease off and the James Clark Ross was able to turn to start the transect at 0600 as planned on 8th April. The conditions had actually only lost us one day of transects, leaving the last 3 days of the core box still ahead of us. The first two transects were undertaken as usual, firing XBTs at regular intervals (see 23 November diary entry for full descriptions of the western core box), finishing at about 1600. The evening, as with the last western core box, consisted of time spent trawling for Krill using the Rectangular Mid-water Trawl (RMT), though this time trawling was undertaken for set periods, comparing catch and average krill size at the various depths trawled. Four trawls were undertaken during the evening, finishing at 2200, giving the BIOPEARL team the chance to then undertake a further AGT and EBS in the area, with work finishing at 0130.
Pictures by Huw Griffiths
The next day had an identical plan, starting at 0600 with 2 further transects, and again followed by four hours of RMTs undertaken in the same way as the previous day. The BIOPEARL team again took advantage of the hours afterwards, undertaking a deep EBS to 1500m, finishing at 0200. The third day of the core box consisted of the final 2 transects and then the re-deployment of the two moorings recovered last week. This all went nice and smoothly, with the JCR heading off in the direction of Shag Rocks at around 1800. After having the first day of the Western Core Box hove-to, the weather had significantly improved and, despite its reputation for causing the JCR to roll, most on board managed to sleep soundly throughout the four days.
Picture by Steffi Kaiser
Overnight the JCR steamed west to Shag Rocks, the final BIOPEARL transect, and the last science for the JCR this season. The deck work, as usual, started soon after first light, with the two deep stations completed by 1830. Over recent weeks this area has been renowned for the presence of up to 15 Blue Whales. Over the day's trawling a number of large whales were seen, though none of them were ever closer than several miles from the ship, making it difficult for those on board to safely identify them to species. The previous day's work had left only the two shallow stations still to complete. These were finished in 5 hours the next day and the seasons scientific work was over. The JCR thus was set on a course for Montevideo, where the scientists would be demobilizing several days later.
Although the long hours of deck work were now finished, this became the point that many of those on board stopped being able to sleep. It was on the 14th, the next day, that the ship, for the first time this season really hit truly unpleasant weather. Throughout the morning the winds had been around 30 knots, though, all of a sudden the barometer plummeted like a stone and the winds increased. In a matter of minutes the wind was gusting to 80 knots. At this point the swell hadn't had time to build up, though happily did so over coming hours and days. Although wind dropped, the ship became an unpleasant place to try and sleep for the next few nights.
Friday evening, prior to another night of not being able to sleep, was marked by the first 'pub quiz' for this half of the season, arranged by Matt (Dive Officer) and myself (Dave the Doc), being finally won by the four-person team of Jan, Rachel, Dan and Rich the Purser. The next day was to be the 'End of Cruise' Dinner. The question really would be as to whether the swell would continue, and if so, would plans need to be changed for the Dinner; a buffet on a rolling ship would be little more than a mess.
Anyway, for that, and the ships arrival in Montevideo, you will have to wait until next week.
The Penultimate Science bit for JR144 (and also the season)
During the course of the science cruise SCUBA divers have carried out dives at Deception Island, King George Island, Signy Island and South Georgia. The divers were collecting specific animals required for experiments that were being carried out on the ship. The animals collected included fish, limpets, starfish, brittle stars and a type of small shrimp called an amphipod. The animals were brought back to the ship, and placed in aquarium tanks containing seawater at a range of water temperatures. One tank contained seawater at the same temperature as the sea at the site where the animals were collected, and the other two tanks contained seawater at temperatures 3 or 6oC warmer. The aim of the work was to examine how current, and predicted regional warming of the seas around the Antarctic may affect marine animals. Previous studies have shown that many Antarctic species cannot tolerate water temperatures even a few degrees above their normal water temperature. In turn, this means many Antarctic marine animals may be at high risk from even small increases in seawater temperature. In the current studies, we have been looking for changes in the gene expression of animals when exposed to small increases in water temperature. Measuring changes in gene expression may allow us to use animals as highly sensitive biological indicators of seawater warming. Genes are important because they are the plans and template from which an animal manufactures proteins. Any change in gene expression will in turn alter the types, or amounts, of specific proteins that the animal is producing. Proteins are one of the most important components of an animal, and perform a huge range of tasks, from being one of the major building blocks of growth to acting as enzymes and cellular ‘machines’. Examining changes in gene expression at elevated temperature will hopefully allow us to understand why Antarctic marine animals are so intolerant of elevated water temperatures. In turn, this may allow us to utilize changes in gene expression as a highly sensitive indicator of thermal stress resulting from global warming.
And here is some of this Week's Wildlife from Shag Rocks
Pictures by Steffi Kaiser
Picture by Huw Griffiths
Here are the last few science staff from this cruise
Picture by Steffi Kaiser
Now that should be every member of this last cruise's science staff accounted for. They will be all leaving us alone on the James Clark Ross for the journey north..........but that's next week.