It was another good and productive week on the ice. Rory only needed two days to get back up to speed which was important considering our tasks for the week.
I wanted to see if there was a similar feature to the wall of bacteria that we saw at cinder cones anywhere else. A likely location would be Turtle Rocks (also there was a hut there so we might as well check.) There was no wall of bacteria but there was some great marine life.
Crinoids, at one stage of earth’s history, ruled the oceans. Now they are relatively rare to find except in a few key places. We hadn’t seen any yet this year but found a few at Turtle Rocks.
This sponge was a pretty one with the lightening ice in the back ground. Sponges are very difficult to identify, even in areas such as this that have a legacy of over 40 years of research.
I’d never seen Pycnogonid reproduction before this year and it has been everywhere. In the back you can see the silloutte of Rory. There has been an incredible increase in ice algae changing the blue hue of the water early in the season to green.
Pycnogonids are supposed to eat Cnidarians (anemones and such) and Tunicates (Seasquirts). No one seemed to have told the Antarctic pygnogonids that thought. This one is eating a gastropod (snail – likely Amauropsis rossiana) and we have seen them eating pteropods as well (another kind of mollusk – better although poorly known as sea angels.)
It can be challenging to take photos of the animals under the ice. Here’s Clint Collins doing something challenging.
The green of the ice algae and the activity of the cracks makes the sky (i.e. frozen surface) just amazing from below. This is a site where many seals have access to the air because of the ice dynamics that keep breathing holes open for much of the year.
The rest of the week was breaking down our final time point from our experiment. At this point we have had samples running for 6 weeks straight without a problem. It is a huge relief to finish up the last 24 samples. The algae that we added to them all has been either eaten or buried. Green surfaces have become brown again and there are many happy worms even after over a month in these conditions. A few more dives and we are done. Here is a view of an especially wormy core:
The community is still ‘alive and kicking’ after 6 weeks of experiments.
Today started in the not so usual fashion. Rory woke up raring to go and headed to the gym. En route he pulled a muscle in his back and that pretty much ended his day at around 7am. We were going to go to a new dive spot where I heard that there was a pretty cool sediment feature to check out. The place is pretty close to station and called cinder cones.
Immediately upon entering the water I was blown away by the ice shapes. There was an incredible amount of ice algae providing a strange mix of colors and the sea ice cracks were spectacular.
The bottom of the sea ice with strange hues of green (ice algae) and blues (ice).
The real find was the wall of bacterial mat. The bacteria here uses sulfide (H2S) and mixes it with Oxygen to get energy. Its a chemosynthetic process so does not use the power of the sun.
The white in front is bacteria not ice. Its a thick mat of it and is an indication of interesting chemistry in the sediment below.
I now get to sort through the core to see what lives in it. I have high hopes as communities like this have been a focus of my research in the deep sea and I am excited to see what the cold microbial mats contain at a shallow 40ft.
The snowfields of the permanent ice shelf meet the cravasse filled slopes of Erebus.
For the last two days, Rory and I have been staring through microscopes. I’ve been enamored with the microscopic world while he has been counting little glowing dots in the dark. But I think we both have been thinking about our hike that we took last Sunday.
The walk to Castle Rock is along a ridgeline right above town. The entire route is flagged making it safe to travel and it is constantly monitored for shifts in the ice that would make it unsafe. There is even a safety shelter that you can see as a little red dot. As the weather here can go from this (calm, no wind, warm at -11C) to hurricane force winds and wind chills down to -70C in less than an hour. Anytime you are more than an hour from the station you must have a way to shelter yourself and survive such a storm.
This is the goal. Castle Rock. It is only a 3 mile hike but that takes a bit longer than it would elsewhere since we have to be dressed for the occasion.
Later in the season there is a route to the top of the rock but right now we can just hike up to the saddle before the climb. Here is Rory doing just that. The real challenge that day was not getting too warm! With the sun out and no wind I didn’t even don my Big Red (i.e. red coat) and instead sweated away in a fleece. Rory wore his Big Red as a cape.
This is the view north. You can see an ice tongue off as a different shade of light about half way to the islands. That ice tongue causes many cracks in the sea ice that we have to monitor as we travel around. The islands are Tent Island, Inaccessible Island, and then Big and Little Razorback islands before the north end which is Cape Evans and one of the sites we occasionally dive.
The Expanse Looking South. The next stop here is the south pole. Flat. White. Snow and Ice for miles. This is the view the initial explorers saw as they attempted to tackle the continent at the turn of the last century. It is still an awe inspiring view and so close to where we live and work now.
Julia McFarland’s 7th Grade science class from Egan Junior High School from Los Altos, CA asks:
How thick is the ice and when you jump in how cold is it?
The ice is currently right around 1.4 meters thick or 4- 5 ft. The water is -1.8C or 28 F. This is two C below freezing and as cold as seawater gets before it freezes. As soon as we jump in all of our skin that is exposed, which is only our lips, goes numb immediately so it really is not that cold after the initial shock.
You can see here that we are pretty much entirely covered up. The little sliver around our lips is all that is exposed.
The ice is slowly thickening during this time of year and at one of our dive spots it has gotten to around 12 feet. A lot of that ice is unconsolidated “brash” ice which means if we touch it it moves more like a slushy or more like snow than ice. Starting in mid to late November the weather warms where the sea ice is no longer thickening and it will eventually break out. This normally happens every year but every once in a while the sea ice will stay here for a few years creating very thick ice, in the past decade we have seen 12-18 ft of ice where we have 3 ft this year.
This is what the bottom of 12ft of ice with 6ft of snow on top looks like.the jagged ice around the side is the brash ice.
As the season progresses a few things happen. The visibility in the water gets worse, the station gets crowded, and other animals start showing up. While this normally just means seals that have come up to pup, there are also weird wanders.
This Weddell Seal was quite happy to make use of our dive hole to come out and relax in the sunshine. Because he was there we ended up diving outside of the hut (meaning we were exposed to -25C with windchill while getting ready to jump in the oca) so the seal would keep access to the ocean. But we couldn’t really argue with a face that that.
While we were underwater these two Emperor pengiuns happened by. We had seen them earlier as we were driving to the site. They came right over to me on their bellies scooting along. One of the nice things about working in an area where humans don’t harvest the wildlife is that the animals are curious about us and so as long as we stand still they come say hi.
Why walk when you can scoot?
I think this is the secret to moving on the ice. Stay low and you never fall far and won’t trip on a ridge of ice.
We went out that day to dive on a new site. It was very interesting in that it was the top of a sea mount at the end of a glacier tongue coming off an active volcano. The entire top was covered by a single species of sponge, a few anemone’s and bunch of nudibranchs that were eating the sponge.
There was a great field of nothing but this on top of the seamount. It was just discovered in the last few years and we were the first divers to see it. Very cool. We were there en route to another dive location with the group that was studying it. Since we were sharing resources we decided to dive too.
The real purpose of the trip for us was to get some samples of the bacterial rivers coming from underneath the glacier. I put in a photo of it before but the more we talked about it the more we thought it could be something very novel so we went back. Rory and I spent the better part of a week devising multiple ways to get through the ice and collect samples of it. Amazingly the first approach worked. We took a sample from the vein of the glacier using the same technique as if it was our arm 0 using a really big syringe with a really big needle. I was most proud of not stabbing myself in the hand with the needle after taking the sample. While normally we just discard needles rather than recap them – that is not an option when you are at 90ft with nothing but a mesh bag and are floating around in a big balloon (i.e. drysuit) that doesn’t like sharp things.
This syringe worked surprisingly well to get the sample from beneath the ~3cm of ice. You can see the wall of ice that was ~ 90ft to the seasurface and another 90ft above that towering over our head. The syringe saved us from using ice screws, a hammer, a hole making bit from a drill, and a bunch of other things that Rory had brought just in case.
Here’s another view of the wall for perspective.
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.
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:
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.