Day 5 Wanderers, a whale and a box full of sand

The box corer is deployed

Antarctic Minke whale

Albatross in flight

Albatross

The James Clark Ross is nearly 200 miles from the Falklands. On the science menu for today is more coring - if possible we'd like another sediment core from the long gravity corer which worked so well yesterday. But nobody has looked at the seafloor in this area before, so sending down the long steel tube into what could be solid bedrock would be a bad idea, so we first check the composition of the seabed.

On the way to the designated site, the coring scienists monitor the TOPAS display on the ship computer system. Topas is a sub-bottom profiler that can see through the first few metres of sea bed and give clues to what it is composed of. The instrument sends sharp acoustic pings through the water column and into the seafloor. From the returned echo an approximate image sea bed and what lies beneath is reconstructed. This thing is like an echo sounder on steroids - a bit like an x-ray fish finder, but way more powerful.

The ship did a couple of laps around the site to sample the seabed at 3000m water depth. The sub-bottom profiler was switched on the whole time. At first the output didn't look too good, but as long as it's not solid rock we should be able to grab a core. If a site is surveyed for the first time it's much safer to send a box corer down first. This is a large steel crate with a spring-loaded shutter at the bottom - just like a very heavy mouse trap but catching mud instead. When it hits the bottom, the box sinks into the mud, and the spring releases to close the box before its precious contents are hoisted back on deck. This device is used to sample the very top of the slushy sediment layer where the mud meets the water. The gravity corer on the other hand samples the deeper layers of sediments, but often loses the mushy bits at the top, so having cores from both devices gives the complete picture of sediment accumulation.

The box corer is winched down to 3000m at 30 to 60 metres per minute while the cable carries over 2 tons of tension. Nearly 2 hours later the box corer came back up to the deck, but the crew didn't seem too happy - There was no mud in the box. Somehow the mouse trap hadn't triggered? Several theories as to why that could happen were considered, but it didn't change the outcome. There was no mud!

On the second attempt things looked better - the winch paid out lots of cable until it went slack. That's a good sign because the lack of tension triggers the shutter mechanism. If the box corer had hit the seabed upright and sunk into the bottom substrate we'd get a good sample, so everyone was hopeful that the corer had struck proper mud this time. An hour passed before the corer was on deck again. Everyone's eyes were on the crew who opened the box to take a look inside. They unscrewed the box and signalled the waiting scientists:

Thumbs down!

So no luck again. There was no soft sediment at this site, but at least the box corer had gathered material from the sea floor. All that was in the box was sand! Pretty coarse sand actually, which is surprising this far from land. But still it was only sand and no fine sediments with clues to thousands of years of ocean climate. The sand would give us some answers, just not the expected ones. That's science for you! Best
of all, finding the sand had prevented damage to the gravity corer. If we had sent the gravity corer with the long tube into this coarse material it would certainly have bent or been damaged somehow. Just poke
a stick into fine silt and it glides in - poke a stick into wet sand and the harder you strike it the more the sand turns to concrete. That's what the box corer is used on sites that are unknown. It only samples the top half metre of sea bed with a really robust mechanism and can therefore prevent damage to more fragile equipment. However, a small plastic bag of the sand would go to the lab for analysis, but that was to be all for science at this place.

While most of us were assembled on the deck to watch the recovery of the box corer, an antarctic minke whale came to the side of the boat. It breathed out just 10m from us over on the starboard side. Antarctic minke whales are known not to blow, so the exhalatin sounded more like a sigh instead. Nobody had their cameras ready for this unexpected encounter. My photo above is of the second time it breathed, but this
was already much further away.

Spurred on by a close call with southern mega fauna, I stayed on deck with binoculars and camera and watched the albatrosses that had gathered around the ship. This was the first time I saw a Wandering Albatross close-up - it had settled on the water just over the stern. These huge birds have a wing span of up to 3 metres, but at a distance look just like a sea gull. Only when they come to within a few metres of the ship it becomes obvious how absolutely massive they really are. The photo of the albatross in flight shows a Royal Albatross - also a big bird, but not quite as huge as a wanderer. Whichever species it is, their flight is one of the great experiences of the Southern Ocean. They glide over the waves, wings far outstretched and the wing tips almost touching the waves. They use the ground effect like they'd studied airplane dynamics and ride the updraft created by individual waves. The wings hardly move, as most of the energy comes from the wind itself and the albatross is
just going for a ride.

I wish I could put something for scale next to an albatross. Let's say a rottweiler or a small child - a fully grown wandering albatross could match that size. But don't think of them as freakishly big sea gulls - the bird experts on board wouldn't be happy about that ;)

We are now in transit to our next station - over 1 and a half days sailing away - at Orkney passage, a gap in a sea floor ridge near the South Orkney Islands. These slands lie south of 60 degrees and are part of the British Antarctic Territories. South of 60 I shall be in Antarctica proper and I brought a special beer can with me to celebrate this occasion. But we're still in the 50s (degrees of latitudes) and it's still a long way through the Southern Ocean.