We arrived back from our survival training having successfully survived. Today we went north to help out a fellow science group. Since there are only three approved divers on station at the moment and we always (both by requirement and common sense) dive with a buddy, we were asked to join Steve as he did some collections and checked on an instrument. Not all groups that need access to the ocean bring divers, many rely on the station divers. The first dive was at a spot that has a glacier running right down into the water.  Since there is lots of snow on the ice it is pitch black underwater with only a few areas where light peaks through cracks.

This is the view looking along the ice wall. the sea ice is above and other than that it is straight up and down and extends off into the distance.

It is truly an amazing site with yellow bacterial rivers frozen but appearing to stream from underneath its edge.

It was quite dark as there was lots of snow on the ice. Here is Steve, the Dive Safety Officer, swimming towards us with his video light on.

As always. there is amazing clarity which allowed us to see ice forming on the large boulders dropped from the glacier’s persistent movement. Some of the boulders had been there for a long time with large animals growing on them and other boulders seemed to have just fallen off and were completely devoid of animals.

The dive ended with a seal deciding to take some breaths at our dive hole.  After we got out it came up and visited with us, as in kept on looking at us as we packed up our kit.

Here is the seal looking down at us. He was quite happy that we made a hole for him.

The second dive was at a spot that has lots of light and hard hard substrate – no coring possible. But it was neat to see a new site. The ice was in full bloom with lots of algae growing all over except in the hundreds of little brincicles forming on the bottom of the sea ice. There were urchins GALORE.

This is what the seafloor looked like at Cape Evans proper. This species of urchin is Sterechinus neumayeri.

If you look closely here you can see that the urchin is spawning.

Here is the surface of the ice. You can see many many little brine-cicles that form when the sea water freezes. Seawater forms freshwater ice and rejects super salty water out of its base. Where this happens these little seawater icicles form. The color of the ice is from ice algae that is growing underneath it. We have not seen much ice algae this year because most of our sites are so dark compared to this one.

It was so bright that you can see the shadow of the dive hut and our vehicle on the surface of the ice from below. You can also see Rory at his safety stop on his way up.

We’re off to a 2-day Field Safety Training Program (FSTP) Snow School course, which means sleeping out in the elements and no time for blogging.

We’ll be back soon with more adventure stories!

One of the nice things about McMurdo is if you wake up too late for a shower, simply walking between the buildings en route to work does a good job of waking one up.  Today was no exception.  Here are some grabs from the weather station that lives on the building next to the lab:

Always a nice way to start a monday…

Talking to a friend down here, he said “days and months can drag by like they are never going to end but weeks always fly by.”  That was sure this week.  We collected a few samples on Monday but the most memorable part of the dive was that we were mirrored by a seal the whole time.  He didn’t feel like getting his photo taken as is clear from this grainy shot below:

This seal was constant company but would not hold still for a good photo.

Rory labeling away. This week we sliced our cores into a total of 288 different containers to undergo a variety of processing later.

But the main task for the week was breaking down one of the big time points of our experiment. The cores have started to take on their mind of their own and integrate the food we have given them.

Here is one of our cores mid processing. Each one of the syringes go to a different analysis and the rest of the mud that is not in those cores gets sieved and the species separated out from it.

The processing involves getting a bunch of sample vials and bags labeled and then sub coring the mud with a series of syringes that we have cut the tops off. On Tuesday and Thursday we processed a total of 24 cores, which made up four replicates and each of our six treatments. One of those subcores gets sorted live under a scope and that is how I have spent my waking hours since Tuesday. Here are some of the things I have been looking at:

Spiophanes:

Today we headed out to the more beutiful of our two main dive spots in search of an old cage put on the seafloor many years ago and for me to continue my search of worms. As part of the dive we also got to release an octopus that had been collected as bycatch by one of the fish physiology groups working down here. Their research team collects fish from shallow to ~600m using a variety of methods including using fish traps. In addition to the fish species he collects he also occasionally gets octopods. This creates a bit of a conundrum. While he could release the octopods right back into the wild – the octopods have a very poor chance of survival. Seals will hang out around his team while they fish and an octopus can use its many forms of camouflage on the seafloor, in the water column it can be more aptly described as bait. The only other option is to take them back to the station until some divers can escort the octopus down to the seafloor where it can return home under the cover of benthos. As part of our dive today, we performed that service (it took very little arm twisting to get us to do this).
Here is our friendly octopus trying to escape from his enclosure in the water tables next to our lab. He was moments from freedom (in this case death, rather than actual freedom as he would not do well on the floor ) when I stumbled upon him, snapped this photo, and the gently pushed him back into the water. You can see his arms here floating above the rim of the mesh cage that we had him temporarily housed in.

At the beginning of our dive, Rory put the octpus on his hand and it stuck. Actually it stuck both of his hands together but since that meant Rory couldn’t adjust his buoyancy, he had to coax the octopus onto only one hand. The octopus stayed on that hand the entire way to the seafloor.  After it they reached to bottom Rory had a bit of difficulty getting the octopus off as it seemed pretty content to be on him rather than free. As soon as he got the octopus to let go it took off and stuck to my hand for a while. Apparently this individual likes dry gloves as much as we do.Then the octopus settled down and relaxed on the seafloor as we went looking for the old cages and I continued to look for dense worm communities.

We ended up finding the cage and taking some photos. These cages have been in place for more than 30 years. Everything that is on them that cannot move (what we call sessile) gives us information as to how fast things grow here. For example sponges. The cage was about 3ft high – the same size as these sponge below. How old do you think they are?

Today was a good one.  We started out in the lab processing samples from an experiment that we broke down on Saturday.  Like all weekends we spent the last one working and putting samples into the freezer and preservatives. It feels great to be making progress towards the end of our project, even though that is still a month and a half away.  As we were typing away Rory noticed a lot of people on the ice and pointed them out.  Well it turned out to not only be a lot of people but a quite a few people and a group of very lost emperor penguins.

Its rare to see Emperors here as they normally roost during the winter on the far (far!) side of the island at Cape Crozier. Cape Crozier is 55 miles as the penguin waddles from here adding around 100 miles to these penguins journey. There appeared to be quite a bit of dissent among the ranks as they often stopped and grrrred at each other while walking by the station. This group was likely females on their way back to feed the chicks that they hatched over winter.

The rest of the day we spent jumping in the water to finish an experiment.  We had noticed that as the light become more abundant during the rapidly approaching summer, diatoms appeared on the sediment surface. Diatoms are plankton (i.e. microscopic plants of the sea) and are a potential food source for animals. We decided to measure how much energy these emerging diatoms were producing by doing an in situ (i.e. underwater) experiment.  To measure this we took cores and blacked them out (using some handy electrical tape) and left others clear (replicated at all of our sites, of course). The black cores would let no light in so we knew there was no photosynthesis going on and the clear cores did let light in allowing any plants present to act normally. One black and one clear core were used to collect sediment without disturbing it, and then placed upright overnight on the seafloor. We let them sit there for 24 hours and then measured the amount of oxygen in the cores (we had also measured the oxygen concentration in the water when we set out the experiment yesterday). The difference between the starting oxygen and the ending oxygen of these cores told us how much oxygen was used by the community that we trapped in our cores. Since we know that photosynthesis produces oxygen, the difference between the clear cores and the dark cores tells us how much photosynthetic production is occurring. In other words: Photosynthetic production (measured by O2) = Oxygen produced by photosynthesis – oxygen consumed by the community. The clear cores integrate both the oxygen produced by photosynthesis the amount consumed by the community and the dark cores only measure the amount consumed. Simply by subtracting the amount of oxygen in the dark cores from that in the clear cores to get how much net photosynthetic energy is being produced. The answer? At this time of year the seafloor photosynthetic community is producing ~ 19 mg O2 per square meter. We can use this number (after repeating the experiment a few more times throughout the year) to come up with an estimate of the amount of food benthic (seafloor) production provides for the animals that live in and on the sediment. To put that in perspective, that is about 25% of the daily food used by this community today.

Not everything works as planned though. For example we had issues with sea urchins deciding that they wanted to climb on top of our treatments, knocking them over (this treatment was to measure what was going on in the water – hence no sediment). Not to mention another one deciding that my station marker would make a nice addition to this particular individuals camouflage.

At the end of the dive we took our samples back to the lab to measure the oxygen and saw a nice fish along the way. This is Trematomus bernacchii, one of the fish we often see here, hiding underneath Alcyonium antarcticum, a soft coral.