The Bowman Lab

Science sometimes gets slow due to weather, bad ice conditions, or the availability of equipment. Fortunately there's never a dull day in McMurdo, as the daily events board outside the dining hall shows.

Thanks to the Advanced Biology and Physical Science students of Omak High School for a great Skype discussion this morning, and thanks to teacher Nancy Ridenour for facilitating!

The dust hasn’t settled from yesterday’s flights yet.  The McMurdo Station staff is scrambling to accommodate all the new workers and scientists, and there are twice as many people around everywhere you go.  Another flight should make it in sometime later today, and more flights are scheduled for Friday.   All the chaos has left Shelly and I with comparatively little to do.  We aren’t scheduled to revisit our ice core time series site at Tent Island until early next week, and we can’t continue work on the ice edge until the new safety personnel have finished settling in.  During winfly Jem and Dan handled safety for science parties out on the ice.  During the summer Dan shifts to the communications department, working as a “rigger” to install radio repeaters and other equipment on the high peaks around McMurdo Sound.  These radio repeaters allow outlying camps to communicate with McMurdo Station without the use of satellite phones.  Jen remains with the department involved in field safety, but has her hands full teaching the new personnel!

We expect things to settle down again by the middle of next week at which time we’ll try to pick the pace back up with our field work.  That is if the ice conditions allow.  Right now a large crack south of Tent Island is preventing all vehicle travel in that direction.  If it closes up just a little bit we’ll be able to drive over it with a Piston Bully.  If it doesn’t we’ll have to try and find a way around it, but no one’s found the end of it yet.

With luck, and if ice conditions allow, we’ll be soon be able to switch from using the Pisten Bully to using snowmobiles to reach the ice edge.  In addition to saving a significant amount of fuel we’ll gain a significant amount of time; we can travel a lot faster over bumpy snow drifts in a snowmobile.  To get ready for this shift Shelly and I took the mandatory snowmobile training course today.  We’ve both driven snowmobiles in Alaska but it was good to get some instruction in snowmobile repairs.  The thought of being stuck way out at the ice edge with temperatures dropping and a snowmobile that won’t start isn’t pleasant, but I think we can deal with the most common problems now.

Otherwise it’s time to relax a little and catch up on other work.  Fortunately McMurdo’s a pretty active place.  In addition to two gyms, a basketball court, library, and movie lounge it seems that every night there’s an event (or multiple events) to keep us entertained.  Last night there were two “secret life” talks, where McMurdo staffers talk about previous jobs they’ve had.  One worked as a space shuttle technician at the Kennedy Space Center for eleven years, the other as a scientist right here in Antarctica!

On Saturday night we got some new satellite images showing that much of the new pack ice that’s been forming off of Cape Royds had sheared away from the landfast ice in McMurdo Sound, leaving a very large lead open west of the Cape. Not wanting to waste the opportunity Shelly and I made a last minute decision to head out and see if frost flowers were forming. Dan graciously gave up his day off to join us. We got off to a late start, we’ve all been pushing pretty hard of late and are getting slower in the morning! The need to bridge a large crack in the ice that’s gotten worse over the last couple of days slowed us further, and by the time we got to Tent Island (roughly half way to the ice edge off of Cape Royds) we were running out of time and the weather was deteriorating.

A kilometer or two later we noticed a funny bump on the horizon, almost directly on our old tracks heading out to Cape Royds. Visibility was still okay in that direction but we couldn’t really make out what it was. Distances are very hard to determine on sea ice, it could have been an iceberg at the ice edge 10 km further on or a seal much closer in. As we got closer the bump slowly resolved into a clump of Emperor penguins just off Inaccessible Island, the first penguins we’ve seen on this trip!

We expected to run into the smaller, more numerous Adelie penguins at some point; they have a colony at Cape Royds. Finding Emperor’s was quite a surprise. They are truly bizarre birds, and it’s difficult to imaging just what they were doing so far from either their colony (the closest one is at Cape Crozier, on the other side of Ross Island) or the ice edge. Both Emperors and Adelies are known for wandering long distances for their own purposes however, researchers in the Dry Valley’s have been surprised by Adelie penguins wandering past them in the direction of the Antarctic interior.

These Emperors weren’t nearly that lost – the ice edge was only 7 km away. I don’t know too much about these birds, but my understanding is that we are now in the time when both parents have left the chicks (who hatched back in late July, early August) at Cape Crozier and the other colonies to hunt. So these foraging parents probably decided to take a little sidetrip deeper into McMurdo Sound.

We spent around 30 minutes watching the group, they seemed to be hunkering down in anticipation of the approaching bad weather. By the time we were ready to move on the weather had deteriorated to the point where we decided to turn back. Conditions haven’t improved much, there’s no wind but heavy snowfall and little visibility. We were supposed to get the first two flights of the summer season today (the first flights in a month), they’ve been delayed for 24 hours. This is no problem to us, but frustrating for the McMurdo staff who have been here all winter – they can leave once these flights make it in!

Thanks to the students of Nespelem Middle School for an excellent Skype conversation this morning. I was really impressed by the depth of some of the questions asked! Thanks also to teacher Sheri Edwards for facilitating and writing a nice article about it here.

The University of Deleware polychaete worm team (Stephanie, Annemarie, Adam, Stacy, Mike). Photo: unknown.

It seems like Shelly and I have been doing nothing but filter water for the last several days, but the end is in sight. I think we’ll finish off the last of our samples this evening, then it will be time to turn our attention to getting some new material. It’s difficult to know when our next opportunity to get on the sea ice will be. On Monday the main science season starts. Three planes each week will bring new scientists and staff for the station. There will be a LOT more people around and many more demands on the safety personnel. For the last four weeks there has been only one other group doing science on the sea ice, a team led by Prof. Adam Marsh at the University of Delaware. This group studies the physiology of polychaete worms that live in the sediment of McMurdo Sound. I’m a tad jealous of them because they collect their samples by diving underneath the sea ice, something that I’ve wanted to do ever since I learned it was possible (probably by watching Jaque Cousteau as a kid).

The best organic goo for finding worms is right at the McMurdo sewage outfall. It's a glamorous job! You can see the team's dive hole towards the back of the image. Photo: Stephanie Guida.

Every Sunday evening one of the science groups gives a public talk in the dining hall on their work. Last week Adam and his team presented, this Sunday it’s our turn. I learned some fascinating things about some of the marine ecology of McMurdo Sound. The benthic, or seafloor life in the Sound is very dense, looking much like a tropical coral reef.  Except in place of hard corals McMurdo Sound has large, delicate sponges. The deeper you go the bigger and denser life gets. This is a result of icebergs continually scouring the shallows, removing everything before it has a chance to get large.

Stephanie and Annemarie painstakingly work through each bucket of sediment for the right worms. Here are some freshly captured Capetella. Photo: Stephanie Guida.

The polychaete worms Marsh’s group studies like to live in places other organisms won’t, such as the sewage outflow site for McMurdo Station. Until recently McMurdo didn’t treat its sewage, and the sediments at the old outflow are particularly rich in organics. Bacteria are quick to colonize such spots and consume the organic material so quickly that all the oxygen is used up. The worms can tolerate lower levels of oxygen than most animals, and also like the high concentration of organics. They burrow through it leaving tunnels that allow new oxygen-rich water to enter. This allows other organisms to follow along and further degrade the organic material.

The group is particular interested in a genus of polychaete worms called Capetella. This genus, in addition to being especially tolerant to low oxygen conditions, is highly resistant to many toxins found in marine sediments. In the old days everything from McMurdo Station was disposed of by simply dropping it into the Sound. As a result some places in the Sound are highly contaminated with heavy metals, PCBs, and other chemicals. Bacteria can degrade many of these materials over time, but without oxygen they perform this service very slowly. Microbial degradation is likely much enhanced by actively burrowing Capetella.

A teaching career does have its perks, summers off and... ice diving? Mike suited up and ready for another dive. Photo: Stephanie Guida.

Joining Adam in McMurdo are fellow benthic ecologist Stacy, graduate students Stephanie and Annemarie, and middle school teacher Mike. Mike is in Antarctica through the National Science Foundation’s Polartrec program which pairs teachers with scientists in the field. Mike dives with the team and shares the experience with his and other classrooms via a blog (with lots of great photos). Check it out if you’re curious about what’s it’s like to dive under the ice in Antarctica!

Last week’s successful sampling efforts have left us with a lot to do this week.  On Monday Dan and I went back out to the ice edge to sample mature first year ice, the final sample in our four part set of ultra-large samples from this area.  Completing that was a huge relief, although melting and filtering all of that ice (900 kg total between frost flowers, young sea ice, and first year ice) is going to be quite a task.  We still have to aquire some equally large samples from glaciers in the Dry Valleys, but logistically this should be much simpler.  Sampling at the ice edge went off okay despite the fact that the motor we normally use to power the coring equipment wouldn’t work.  This sort of thing is pretty normal in the cold, so we switched to a smaller backup motor and finished up pretty quick.

Jeff at Barne Glacier. Photo: Dan Mahon.

Ahead of schedule we decided to do a little reconnaissance of some cracks in the ice near Barne Glacier, an impressive glacier that flows into McMurdo Sound from Mt. Erebus.  The absence of multiyear ice from McMurdo Sound and the abnormally warm winter have left the McMurdo Sound sea ice more difficult to travel over than in normal years.  One of Dan and Jen’s jobs prior to the start of the summer season is to map out safe travel routes over the sea ice and identify problematic cracks.  Fractures are everywhere on sea ice.   Most are not dangerous but some can become wide cracks (essentially small leads) over time if the winds and tides exert enough stress on the ice.  A crack can widen to a half meter of more overnight and then be camouflaged under a layer of snow. 

The route we’ve been taking out to the ice edge is in danger of being blocked off by a crack just like this, right now it can only be crossed safely in a couple of spots.  Normally an alternate route can be found inside of (east of) Tent and Inaccessible Islands, heading north past Cape Evans and the Barne Glacier.  Right now this passage is blocked by a large crack south of Tent Island that might heal in the coming weeks, but we confirmed another impassible crack at the Barne Glacier effectively shutting off this route.  We were very lucky to get such good access to the ice edge early in the season; the summer science groups will start arriving next week and some that work around McMurdo Sound will be hard pressed to reach their normal study areas.

The Barne Glacier was as beautiful up close as it looked like it might be from a distance.  At the base of the glacier the sea ice pulls away, leaving an easy access point for seals.  Seals were lying all around the ice at the base of the glacier and we could see a number breathing through the thin ice there.  After the glacier we headed to our second objective for the day, a site near Tent Island where we are taking periodic ice cores for a time series of microbial community composition during the seasonal transition.  Here’s where the day got a little bit interesting.  We were within sight of being done and back to McMurdo in time for dinner (which rarely happens when we head out) when the ice corer become very stuck in the ice.  As I mentioned earlier the large motor that we normally use wouldn’t start in the cold.  This motor drives the corer slowly, but with a tremendous amount of torque.  Instead we were using a much smaller, faster, and weaker motor.  Midway through drilling the core barrel stuck in the ice, firmly frozen in place.  This happens sometimes with very cold ice. 

There's not way we're rotating this corer out, time to start digging...

The next couple of hours unfolded comically as we went to more extreme lengths to get the core barrel back out of the ice.  After about thirty minutes we realized that no tool at our disposal was going to get the barrel to back out by turning, so we decided to excavate.  This was a little unnerving, core barrels are expensive and made of fiberglass, so they are easily damaged.  The last time I saw one get dug out in a similar situation it sustained serious damage.  We slowly but surely chainsawed and picked a pit around the corer and eventually got it free.  Totally exhausted we finished up and headed for home.

Satellite views of Cape Royds on 9/21, 9/22, and 9/23 showing the rapid freeze up of the lead that opened on 9/20. Cape Royds is the southern (bottom) projection of land. The small islands south of Royds are the Dellbridge Islands. The odd white feature south of the islands is the Erebus Glacier tongue. This is an unusual instance of a glacier intruding far into marine waters, usually they break up into ice bergs relatively quick. The tongue does calve icebergs but not enough to prevent the extension.

It’s been good frost flower growing weather in McMurdo Sound over the last few days and we benefitted with an excellent collection on Friday.  Heading out with Dan and Jen we got as close to our old sampling site at Cape Royds as we could, which it turns out wasn’t very close.  The ice had sheared off further from the old edge than we had thought; you could see our old tracks go right off the ice edge!  In this case the edge didn’t mean open water though, temperatures have been hovering between -30 and -40 C (approximately -20 to -40 F) driving a lot of new ice formation.  The photo above shows the whole evolution of new ice edge, starting with the first satellite image of the area for the season on September 21.  The middle image is from the 22^nd, and the right image is from the 23^rd.  On the 21^st the thick black line is the new lead between the land fast ice to the south (bottom in the image) and the drifting pack ice to the north.  Only 24 hours later in the middle image the lead has frozen so solidly that it is indistinguishable in the satellite image from the older young ice present elsewhere on the 21^st.  That sudden growth of young ice seems have held everything in place between the 22^nd and 23^rd.  Despite a persistent breeze from the south there is almost no change to the location of individual ice floes.  Yesterday the wind really ripped through McMurdo Station and we don’t have the next satellite image yet.  It’s entirely possible that an even newer lead has opened between the land fast ice and the pack ice!

Flat Stanley's excited to start collecting frost flowers.

Virtually every surface of the young ice that we visited or could see from standing on top of the Pisten Bully on the 23^rd was completely covered in frost flowers.  Out in the pack ice, where young is continually forming throughout the winter, the frost flower environment is impressively vast.  Spatially it’s much like looking out over a vast grassland.  It’s partially their extent that makes frost flowers interesting.  Because the ice surface temperatures are so low any microbial metabolism within frost flowers must be low, but the cumulative effect within all the frost flowers present at any one time could have interesting consequences.

Going big with sample collection. In this haul we pulled in 300 kg of frost flowers and equal quantities of young sea ice and seawater. The seawater we have to keep in the vehicle so it doesn't freeze on the ride back.

On this sampling effort we needed to go really big.  Our final analysis requires a lot of DNA, so we need a lot of bacteria!  Taking advantage of the fact that we could drive nearly to the frost flowers we almost doubled our haul from September 19^th, pulling in 300 kg of frost flowers (661 lbs) and equal amounts of young sea ice and seawater.  Now comes the really hard part, getting all that material melted down and filtered!  It will take us more than a week to get caught up on that part of the process, and in the meantime we still have to collect an equally large quantity of mature first year ice to round out our sample set.  We might have to divide-and-conquer tomorrow to avoid falling behind schedule, with Shelly filtering and me getting more ice cores.  Whether we can do that depends on whether we can get Dan or Jen to spend a whole day helping me in the field…

I haven’t yet spend a lot of time on this blog talking about working or living conditions here at McMurdo (both are pretty good).  To give a little introduction to Crary Lab, the excellent new science building where we’ve been spending much of our time, I’ve prepared a short video tour of the -1 C cold room where we do most of our sample processing.  To go along with it there’s a 360 degree photosynth of the room, and as a bonus a similar photosynth of the station from the Crary rooftop (I needed an excuse to play around with photosynth some more).

I know there are several teachers with classes reading this blog.  We would like to visit a select number of classrooms via Skype (or an alternate media, possibly Vyew) over the next 2-3 weeks to share some of our experiences and to let students ask questions.  As you might be able to tell from reading this blog we have to retain a certain amount of flexability in our schedule in order to take advantage of changing conditions.  As a result we don’t know how many calls we can accomodate.  Priority will be given to teachers with whom I’ve already communicated with on this subject (including teachers of the PSBB Millenium School), followed by first-come first-serve.  You can sign up via Google Docs here.  Once I have the information specified on the sign up sheet I will email you to arrange a specific day and time that works for your class and to work out any technical issues.

McMurdo Sound, right about the time the temperature hit the record low so far for this year. The memorial visible on the hill is Vince's cross, George Vince was a seaman on Scott's first voyage to Antarctica.

It’s a cold one today at McMurdo, we just past the magic temperature of -40… the point where the Celsius and Fahrenheit temperature scales converge (briefly).  This is the temp without windchill, with the windchill it’s a brisk -59 C (-74 F).  I took a brief walk to snap this picture of the sunset and made the mistake of facing into the wind for a few seconds, the tears froze to my face instantly.  I wouldn’t want to be at the ice edge right now (it was much warmer when we were there on Monday), but I bet young sea ice and frost flowers are forming everywhere on the open water. 

We hear a lot about windchills and we’ve all experienced how much cooler it feels when the air is moving past us.  Many people misunderstand the term however.  It’s not that the air is any cooler when there’s wind around, we feel cooler because we’re losing heat so much faster.  This heat loss is what the body registers as temperature.  A piece of metal placed outside at -40 C with a windchill of -59 C will never get colder than -40 C, but it will reach that temperature much faster than on a still day. 

It’s been a warm, snowy year and as a result the sea ice around McMurdo Sound is warmer (and thinner) than usual.  Among other things this has being causing problems for travel over the ice; cracks and weak spots are continually appearing.  Today’s low temperatures, aided by the wind chill, should rapidly cool any exposed ice surface and have a noticeable impact on ice growth and ice strength. 

Update… I just got word that it bottomed out at -42 C, the coldest day of the year so far for McMurdo Station!

Young ice rafted up at the ice edge. The ice floe that we ultimately sampled is on the right. This photo is looking south toward the land-fast ice, you can see Mt. Discovery in the background.

Yesterday we finally made it out to where we can sample frost flowers, retracing Dan and Ryan’s track from Saturday out to Cape Royds.  We were stopped from reaching the ice edge itself by an abrupt transition from ice over one meter thick to ice only 50 cm thick.  In reality this is plenty of ice to support the weight of our vehicles, but McMurdo Station rules prevent vehicle travel on ice thinner than 76 cm (30 inches).  So we parked our vehicles, shouldered packs, and headed to the ice edge to see what we could find.  To understand what the ice edge looks like right now it’s necessary to understand the weather conditions over the last several days.  We had an intense period of wind blowing primarily from the SE, followed by a couple of nicer but cool days, and finally a day of mild but persistent north wind.  Yesterday was absolutely beautiful, possible the nicest day since we arrived.

Sampling frost flowers is as easy as scraping them from the ice surface with a clean shovel into a sterile plastic bin. Photo: Shelly Carpenter.

The period of strong SE winds cleared the ice edge of any recently formed ice, leaving an abrupt line between thicker, land-fast ice (ice that is anchored to the shoreline) and open water.  In the open water ice still would have been forming, but the wind would have quickly driven this young ice out toward the open waters of the western Ross Sea.  Once the SE winds ceased ice would have formed in place, some of it attached to the land fast ice and some of it drifting freely.  Sunday’s mild north wind would have driven all of this ice south, against the thick land-fast ice.  With nowhere to go this young ice would have “rafted up”, with some floes getting pushed underneath others.  Think of a much scaled down version of the plate tectonics that gives rise to ocean trenches and mountain ranges.  This is what we found at the ice edge yesterday. 

Sampling the young ice underneath takes a little more effort, but the work still goes pretty quick. Photo: Shelly Carpenter.

A young ice flow that is rafted on top of another flow will quickly drain of salt, and presumably of many microorganisms.  As a result this ice is of limited use to us for our current study.  Fortunately we were able to find a large pan of young ice that had not rafted.  Had the north wind been stronger we might not have found anything suitable in the area.  Like all of the other floes we observed this one was completely covered with very salty several day old frost flowers.  We did a quick check of the salinity of the frost flowers, the whole field was almost three times the salinity of seawater.  Bacteria generally get transported with salt in sea ice.  More salt means more bacteria, so this was perfect!  We trekked back to our vehicles to collect our sampling gear and get to work.

This is a profile of the young ice that we sampled, with the top of the ice on the right and the bottom of the ice on the left. The growing ice front, or bottom horizon where the ice is adding thickness is defined by the white band. Below the white band frazil ice is accreating to the underside of the ice. As ice continues to accreate the band will move steadily downward driven by the movement of the freezing point lower in the ice column.

It didn’t take us very long to collect perhaps 500 kg of frost flowers, young ice, and water.  It took much longer to haul these samples 2 km back to the vehicles.  We had counted on being able to drive much closer to where we wanted to sample so we only brought one small sled for hauling.  Not nearly enough unless we wanted to make a half-dozen trips!  So we improvised a sled from a plastic containment berm that we use when fueling our saws and drills in the field.  Not ideal, but it got the job done.  However there are sore legs and sore backs all around this morning.  Many thanks to Dan and Kevin (who volunteered to go out with us yesterday), we couldn’t have done it without them!  We packed up just as the sun was setting and got back in time to eat a late dinner before turning in.  This afternoon Shelly and I will begin the much longer process of melting and filtering all of this material and sorting out our field gear for the next excursion…

Putting our backs into it. Dan and I reenact some of the finer scenes of Antarctic exploration in an effort to get our samples back to the vehicles. Photo: Shelly Carpenter.

After some initial seal related frustrations we were treated with a spectacular Antarctic day. It's a little difficult to make it in this photo, but at one point we got a beautiful double "ice-bow". The source of the ice-bow is the same as a rainbow, except that ice crystals not water droplets are causing the refraction. You can make out the large red splotch where the seal left one of his or her many markings on around our old pool.

I said it was good to have a Plan C as well.  Sunday’s normally a day off at McMurdo but after breakfast we headed out to check on our not yet complete frost flower pool and to see if we could get a little further on removing all the ice from it.  Unfortunately it was immediately apparent on arriving at our site that we’d have to abandon Plan B.  The seal that we had seen nosing around the day prior had clearly claimed our pool as a hang out spot, with a neatly maintained seal hole in one corner of our pool.  That alone wasn’t a huge problem but seals are pretty messy animals.  Like other aquatic creatures they aren’t too picky about when and where they relieve themselves.  Seal holes are usually pretty well marked with fishy pink excrement and this one was no exception.  In fact this particular seal seems to have gone above and beyond the norm in this case.  From a microbiological standpoint the pool is irrevocably contaminated even if we could get rid of the seal, which we can’t.

Our intrepid volunteer for the day Sandwich (neither Shelly or I got the backstory on her nickname) gets ready to drill some holes in our new pool.

It was however, a beautiful Antarctic day and we didn’t want to waste it.  We quickly hatched Plan C, which was to dig a pit about half the thickness of the ice and then drill a couple of small holes all the way to the bottom.  This shouldn’t look that attractive to a seal as a breathing hole and should give us some frost flowers.  The downside is that this sort of pool isn’t going to circulate as well as a pool with an open bottom.  I don’t know exactly what this would mean for the marine microbial community that might ultimately end up in the frost flowers, but it might not exactly represent a natural situation.  But then again it might be good enough.  If we are unable to sample natural frost flowers a few such pits (if they work) might get us the samples we need.

And here's our new seal-free pool starting to freeze over.

Fortunately the chance to get some natural frost flowers has never looked so good!  Dan’s long scout with Ryan, another McMurdo staffer on Saturday was pretty successful.  Maneuvering around cracks and thin ice they were able to get to Cape Royds.  Enroute they past some small leads chock full of frost flowers.  Even better from Cape Royds they were able to see the ice edge, with large expanses of young ice leading to open water.  Although they didn’t get out on this young ice it has a whitish look that suggests it is covered with frost flowers.  With luck we’ll be on our way up there early tomorrow, pending approval from the McMurdo Station managers and good weather…

First glimpse of an Antarctic frost flower, from Dan and Ryan's trip to Cape Royds on Saturday. Photo: Ryan Wallace.