Adam has joined us from Southampton University where he studies the reproduction and morphology of bivalve molluscs in the Southern Ocean. Like their clam and mussel relatives, Adam’s tiny Antarctic bivalves get their food by filtering seawater. Adam is particularly interested in how the species respond to different environmental conditions such as sediment types, depths and temperatures. In the Southern Ocean, bottom water temperatures are a lot more stable than elsewhere, which means that species here may find it more difficult to adapt to temperature changes… a theory which Adam is keen to test.

To see how well his Southern Ocean bivalves respond to small, regular increases in temperature Adam has to work in the 4°C cold room on the ship, one of the best opportunities to study his animals alive as they are hard to maintain in captivity. At the bottom of the Southern Ocean they live at around -2°C! By slowly increasing their water temperature and measuring their rates of oxygen consumption he can test their thermal tolerances and in turn determine how the species may respond to rapidly changing environmental conditions. In this way he can learn about their capacity to adapt, which is useful for understanding the evolutionary history of bivalves in the Antarctic, and for predicting how these species may cope under potential ocean warming in the future.

So far he has been able to test one shallow water filter feeder species and two deeper water deposit feeder species. He is really hoping to catch more of the deeper water species in the next few days to make the most of this opportunity.

Adam Reed with Southern Ocean bivalves. Photo: Jen Jackson, BAS

Jen Jackson (British Antarctic Survey)

Hello from the eastern Weddell Sea! On Sunday 19th February we reached the most southerly point of our expedition. At 77.36 degrees south we had made it as far south into the Weddell Sea as the sea ice would allow us to go – only 30 nautical miles short of the James Clark Ross southern record for this area. On the 17th we began to break into areas of sea ice. The James Clark Ross has a special ice heeling system which makes the ship roll from side to side, helping to ease our passage through the ice. We travel slowly through and stop frequently as the captain searches for a route through the existing cracks, targeting the weaker areas where the ice is more likely to break. The best place to watch this is from the very front of the ship, where you can peer over the prow and watch the action happening directly below.

Sea ice. Photo: Jen Jackson, BAS

The sea surface temperature is now around minus 1.5°C. At this temperature it is so cold that the sea changes in consistency. Ice crystals under the surface dampen the waves giving the sea around us a completely glossy and smooth appearance. Despite the complete lack of haze, it’s often hard to distinguish the sea and sky at the horizon. Minke whales patrol the sea ice; rising in the small pools that form where the ice fractures and separates. The groups of flapping Adelie penguins from the last few days have now been replaced by calm clusters of emperor penguins, craning at us from the sea ice.

Emperor penguins. Photo: Jen Jackson, BAS

The Weddell Sea. Photo: Jen Jackson, BAS

Minke whale. Photo: Adam Reed, University of Southampton

From the 19th we have been slowly tracking north along the Antarctic coastal shelf and into deeper waters, collecting sea floor animals from 300 to over 2,000 metres deep. Each ‘sampling station’ consists of three Agassiz trawls and one epibenthic sledge, which were described by Mel last week. Life on the Antarctic sea floor is incredibly patchy, so we get a much fairer representation of it with three repeats. In the evenings we can review the high quality camera footage of the sledge and get a good look at the habitat we are collecting animals from.

Sea life at our most southerly site included loads and loads of sea cucumbers. We collected well over 200 of these little fellows. When they come out of the sea in the net they look like slime and sludge but are beautiful in the water (at least I think so!). Mel Mackenzie, our sea cucumber expert from Museum Victoria in Australia, was really happy and was kept very busy sorting and identifying. The most exciting part was that we learned a lot about the biology of these little animals from our underwater video camera. We collected excellent footage of a whole ‘city’ of sea cucumbers, each one sitting in a little pit it presumably had dug into the mud. It is wonderful to see the animals in action and we have learned some new things about sea cucumber behaviour in the Southern Ocean.

Agassiz trawl samples: Photos by Adam Reed & Camille Moreau

Our first day of sampling at 2,050 metres yielded an amazing diversity of deep-sea life, from countless worm tubes to loads of tiny sea spiders which clung to the nets on the way up. We spent a fair bit of time picking them off the nets and deck with forceps. The glamour of biology!

BAS cruise JR 275 departed the Falkland Islands on the James Clark Ross in early February and will sample the South Scotia Ridge, southern South Sandwich Islands and Weddell Sea before returning to Stanley in late March. This Antarctic research cruise is running three scientific programs: a biological program collecting animal samples and video footage, a geophysical program including seafloor mapping and collection of rock samples, and an oceanographic program using CTDs and gliders.

Week 1 – Sailing from Stanley to the South Sandwich Islands – Feb 13 2012
Mel Mackenzie (Museum Victoria)

It has been a surprisingly busy first week for all aboard the James Clark Ross. From the excitement of the first wildlife sightings of whales, dolphins, penguins and albatross as we left the Falkland Islands, to the less-joyous attempts to gain our sea legs as we crossed Drake Passage, the EvolHist (biology) team have been busy adjusting to life and work onboard a moving ship.

Breaching Dwarf Minke whale. Photo: Jimmy Rudd – BAS

On Thursday as we moved into the calmer waters of the Scotia Sea our resident geologist Phil was able to deploy his first ‘rock dredge’ near some seafloor volcanoes. The dredge is a simple but useful tool. Rocks are dislodged by the sharp frame around the first net as it is dragged along the sea floor. This is followed by the effective ‘back up’ of a metal cylinder with a solid base, which can also collect rock (and sediment samples) if the first net is not successful.

James Clark Ross crewmen Dave and Seamus, assisting with deployment of the rock dredge. Photo: Melanie Mackenzie - Museum Victoria

On our second dredge for the day – success! There was a buzz on deck as Phil realized we’d struck what he was after – magnesium-rich rocks called ‘peridotite’. These particular peridotite rocks have been carried by lava all the way from the earth’s mantle, a phenomenon not known from any other place on the major spreading ridges of the ocean floor. These amazing little rocks are still being studied by Phil and his colleagues and have only been collected from this site once before.

British Antarctic Survey (BAS) geologist Phil Leat with his proud haul of 'peridotite' rock. Photo: Melanie Mackenzie - Museum Victoria

On Friday night a lucky few braved the cold night air to glimpse their first iceberg from ‘Monkey Island’ at the top of the ship. My first sighting was just after 5.30 am the following day as we neared the South Orkney Islands. It was a beautiful sight to see these huge bright white plateaus bobbing by, and a sure sign that we’d moved into true Antarctic waters.
The marine geology team had been busy ‘swathing’ our path, bouncing sound waves off the ocean floor to create a ‘virtual map’ of its depth and make-up, and allowing us to choose a suitable site for deployment of our scientific trawl equipment.

BAS marine geologist Gwen Buys with ‘swath’ showing current depth in metres. Photo: Melanie Mackenzie - Museum Victoria

We started our test sampling with the Agassiz trawl (AGT), a sturdy piece of collecting equipment, made up of a metal frame and thick net, and less likely to be damaged if we happen to find ourselves in a rocky area.

The frame and net of the Agassiz trawl (AGT). Photo: Melanie Mackenzie - Museum Victoria

A two minute trawl yielding many of the animal groups we had hoped to see including sea spiders, sponges, brittle stars and many other creatures, even my own favourite sea cucumbers! With only small rocks brought up with the catch it was then safe to deploy the more sensitive epibenthic sledge (EBS) while we sorted through the first catch.

Brittle stars were abundant on our first trawl, often found clinging to sponges. Photo: Pete Lens – British Antarctic Survey

Brittle stars were abundant on our first trawl, often found clinging to sponges. Photo: Pete Lens – British Antarctic Survey

The team quickly sort through the catch, preserving and storing the material for later taxonomic and genetic work. Photo: Pete Lens – British Antarctic Survey

The epibenthic sledge (EBS) with two nets at back and camera at front. Photo: Melanie Mackenzie - Museum Victoria

The epibenthic sledge uses two nets to collect animals from the ocean floor, and this particular sledge has also been fitted with camera equipment, allowing us to glimpse the animals in their environment. Being able to link the preserved animals back to this footage later will help build a more complete picture of abundance, habitat, and interaction between animals. Deploying the equipment requires skill, a good harness, and a little bravery as the trawl is lowered over the back deck.

Crew and scientists deploying the epibenthic sledge. Photo: Melanie Mackenzie - Museum Victoria

Tonight we’re heading towards some volcanic calderas near the South Sandwich Islands. With a little luck we’ll miss the worst of the coming storm and will be able to start our next deployments early tomorrow. But for now, as the ship has started rolling again, I think it would be wise for me to sign-off and grab a hand rail before I get too dizzy!