Ventifacts and More!

Picture 1: Uneven ice surface on Lake
Chad.   

Venitfact - any stone shaped by the abrasion on windblown sand (Webster’s Dictionary)

After a long work week at Lake Hoare it was time for a little fun. I decided to go on a six hour hike that would take me down the shoreline of Lake Hoare and its western counterpart Lake Chad, around Suess Glacier, and then finally up a steep slope to a ridge in order to see some unique geological features called ventifacts.

Hiking in the Dry Valleys isn’t as easy as it is back in the states. Surfaces are often uneven and comprised of material called till, which is loose rocks and sediment left behind on the surface after periods of glaciation. Walking on this material definitely slows down your travel time and can wear out your legs if you’re not mindful to take regular stops. However, the views are definitely worth it once you get going.

Picture 2: View of Lake Chad from the west.  

As I made my way down Lake Hoare and Lake Chad, it was neat to observe the ice features on the surface of the lakes (Pictures 1 &2).  Preferential melting, wind erosion of ice, and movement of the underlying lake water all contribute to these unique patterns on its surface.

Picture 3 Scalloped features in the glacier ice.

Next up on the journey was Suess Glacier. I needed to walk around the glacier to get to my final destination and I found a nice path between the glacier itself and its terminal moraine (A terminal moraine is a mound of till that is pushed up in advance of a glacier as it moves across the landscape).  It was impressive to be so close to the edge of the glacier and observe features such as frozen waterfalls, scalloped patterns in the ice, and melt water streams (Pictures 3 &4). I was also impressed with its overall size as in some locations the ice face was the height of a five-story building!

After rounding the front of glacier, I made my way up a steep hill which provided some great views of Seuss Glacier (Picture 5). It was nice to stop and take in the vastness of the landscape and the sounds of the wind. It was definitely the most isolated I’ve ever felt from human contact, which was also good motivation to keep moving.

Picture 4: View of an ice waterfall located along the front
face of Suess Glacier.

Upon summiting the ridge, I was greeted by one of many ventifacts (Pictures 6-9). The ventifacts consist of boulders that are frequently subjected to high winds. These winds routinely pick up sand grains which scour the exterior of the rock. In some cases this erosion can leave behind smooth polished surfaces while in other cases there appears to be arms extending from the boulder itself.  The wind was really gusting along the ridge and it was snowing so I didn't stick around too long after taking some pictures.

Picture 5: View of Suess Glacier from the opposing ridge.

The return trip allowed me to take in the same sights form a new direction.  I frequently found myself looking at the edge of the lakes which had melted for signs of fish or other forms of aquatic life. It’s an eerie feeling to be an environment almost completely devoid of life forms you can see with the naked eye. It was at this time I was greeted by Taylor, the resident skua (an Antarctic bird) of the valley. It was nice to have this welcome back to camp.

Picture 6: View of a ventifact.

Picture 7: View of a ventifact.

Picture 8: View of a ventifact.

Picture 9: Rock broken apart by freeze thaw action.

My Experiment

Picture #1: View of Anderson Stream
at Lake Hoare.

Now that you have some background on the Dry Valleys, I thought I would take a little time to talk about my experiment. I’m seeking to determine both the amount and chemical composition of suspended sediments in glacier-fed streams. In case you’re wondering what I mean by suspended sediments, it refers to the particulate (= not-dissolved) material that can be carried by a stream. This is the material that can often give streams a brownish color during storms. There is little to no data on suspended sediment loads and chemistry of Dry Valley streams, so I am excited to contribute something new to our knowledge of these systems.

While glaciers may look like pure compressed snow and ice in appearance they actually carry a substantial amount of sediment.  In the case of these Taylor Valley glaciers, much of this material likely originates from windblown dust within the valley along with some potential contributions of ash from Mt. Erebus, a nearby volcano.  However, it is unclear as to whether these are the only two sources of sediment. 

Picture #2: View of VanGuerard Stream at F6

Picture #3: View of gauge located along Anderson Stream.

In order to get a better handle on how suspended concentrations may change over time I designed my study into three parts: (1) periodic sampling of rivers throughout Taylor Valley, (2) daily sampling of two streams of interest (Anderson Stream at Lake Hoare and Van Guerrard at F6), and (3) diurnal (24 hour) sampling of these two streams of interest (Pictures 1 &2). Like many scientific studies, this one definitely requires cooperation.  Samples for the first part of the study are collected by a group known as the “stream team.” This is a rugged bunch of individuals who often hike to several locations in one day in these valleys to collect samples (Lucky for me they agreed to collect additional samples for my study). Samples for the second part the study, the daily sampling, are collected by the respective camp managers for Lake Hoare and F6 (Again, I’m indebted to their generosity).  It’s the third part of the study that fully occupies my time in the field due the intensive time required. 

For diurnal sampling, you’re basically trying to understand how a system, in this case a stream, operates during the course of a day.  While it doesn’t necessarily matter when you begin sampling, it does require you to sample frequently over a 24 hour period. 

Picture #4: View of filtering equipment in the mini-lab
at Lake Hoare.

In order to have some idea as to how much suspended sediment might be moving down a stream, you need to know the concentration of sediment in the water as well as how much water is moving down the stream at any given time. For the latter, I purposefully chose locations where stream gauges, or devices used to record stream flow are already located (Picture 3).  Therefore, my job is to collect water samples by hand at each sample interval to determine sediment concentration.  One catch is that in order to retrieve enough suspended sediment to analyze for its chemistry I need to collect 10 liters of water (Picture 4). That’s basically the equivalent of 2 1/2 gallons of water!

To date, I finished one diurnal sampling of Anderson Stream, which is loc

ated adjacent to the west side of Canada Glacier.  Although the sun shines all day at this point in the year, its relative height and position change throughout the course of a day.  The unique conditions for this area of the valley cause a peak in streamflow around 4pm and another one around 11pm. The lowest flows are recorded in the morning. Therefore, I spread my sampling intervals out during the morning low-flow period. However, from 4pm to 4am I collected samples every hour.  I subsequently brought these samples to the small lab shed where I’ve been patiently filtering ever since!

Picture #5: View of the drainage patterns in Canada Glacier

 illuminated by the nighttime sun.

The one really neat thing about staying up so late to sample is that you get to see the sun hit the landscape in unique ways. Views that seemed ordinary at first suddenly appeared unworldly.  In some cases, this different illumination of the landscape yielded very important information, such as the appearance of what looked like tiny streams with tributaries draining Canada glacier! (Picture #5) Overall, it gave me the distinct feeling that I was working on an alien planet.

The Dry Valleys

Picture 1: Map of the Dry Valleys. The Lake Hoare and F6

campsites in Taylor Valley are shown with stars.

Picture 2: View of Taylor Valley.

The McMurdo Dry Valleys are a series of ice-free elongate valleys located approximately 50 miles across McMurdo Sound from our current location (Pictures 1&2). The Valleys increase in elevation as you move away from McMurdo Sound, and the upper ends of the valleys are occupied by glaciers. These mountains were initially formed during the late Mesozoic Era (~135-180 mya), when Antarctica broke away from other continents and began its southward trajectory to its current location. These mountains are particularly important because they have largely diverted ice flows from the Antarctic continental ice sheet around this area, thus keeping the valleys ice-free. However, during previous glacial periods, glaciers extended well into the valleys and carved them out into their present form.

The Dry Valleys are considered a polar desert, and are one of the driest places on Earth. One of the primary reasons is because the area receives so little precipitation, the water equivalent of about 5cm a year (less than Las Vegas!). Another reason is because cold winds that originate on the Antarctic ice sheet swoop into the valleys and prevent the chance of precipitation. These unique environmental conditions have existed for hundreds of thousands if not millions of years.

So if it’s so cold and dry how are we able to study streamflow in the Dry Valleys? The answer is a few weeks out of the year a combination of relatively higher temperatures and an increase in sunlight during the summer months initiates melting in the glaciers that are located along the edges of these valleys. This glacial melt water becomes the primary source of streamflow in the Dry Valleys. Another relatively minor contribution to streamwater can come from the melting of permafrost, or frozen water, stored just beneath the surface in the surrounding soils. Therefore, each year’s stream flow is ultimately dependent on the relative warmth of that particular summer.

Picture 3: View of Lake Hoare, one of the many closed basin

lakes located in the Dry Valleys

What has drawn so many scientists to study the Dry Valleys is that they are the closest environment we have on Earth to what we might expect on Mars. It is generally accepted that Mars had significant quantities of water in the distant past. However, for reasons we don’t completely understand, much of this atmosphere is gone and any water is limited to either ice caps at the poles or in the soil as permafrost. This hopefully sounds similar, since it parallels what I mentioned about the primary sources of water in the Dry Valleys. Furthermore, some scientists think the Dry Valleys represent the late stages of water cycle evolution on Mars. With seasonal melting from glaciers or ice caps feeding closed basin lakes (Picture 3).

Picture 4: Different life forms found in the Dry Valleys include but are not limited to: (a) lichen, (b) nemotodes, and (c) cyannobacteria mats (Sources: [a&b] NZ Antarctic Biocomplexity Survey, and [c] USFWS Marine Fisheries Research Office).

Finally, many scientists come to the Dry Valleys to study its life forms. After looking at the above pictures you might ask where is the life? However, it turns out the Dry Valleys are teeming with life, just not in forms that we can readily see with the naked eye (Picture 4). Algae are found in the glaciers and lakes, and fractures in rocks (along with lichens).  In some locations, cyanobacteria mats are located along streams or in the lakes. The soils have also been found to contain a large diversity of microbes along with nematodes or roundworms. All of the life forms have managed to adapt to an extremely harsh environment. For a complete description of all the different life forms found to date in the valleys, you can click here: http://nztabs.ictar.aq/dv-biology.php.

In the next post I’ll elaborate more on my own experiment and how it will hopefully contribute to our knowledge of the Dry Valleys.

Into the field!

Picture #1: View of an iceberg trapped in sea ice in
McMurdo Sound.

On Sunday, we took a 40 mile helicopter ride across McMurdo Sound to the Dry Valleys (I will talk about the Dry Valleys and why they’re important in the next post). This was initially going to be a reconnaissance trip to pick ideal sampling locations; however, we decided the night before that it was probably in my best interest to stay in the field for now as stream flow can often be intermittent and sometimes only last for a couple of days a year. Therefore, it was a good idea to get going.

Picture #2: View of the Taylor Valley, one of the Dry Valleys.

Once we traversed McMurdo Sound, our helicopter ventured up Taylor Valley, which might be the most studied of the Dry Valleys (Pictures 1&2). The first stop was a campsite known as F6, which is located in close proximity to Canada Glacier (Picture #3). More importantly it is located near the mouth of Van Guerrard Stream into Lake Fryxall, one of many closed basin lakes (a lake from which there is no outlet to the sea) located in the valleys.  This stream is one of two that I will be focusing on for my study and the good news is that it was flowing!  We took a sample volume of 20 liters, which I will later filter in order to determine the amount of suspended sediments being carried by the stream.

Picture #3: View of the F6 campsite.

Picture #4: View of the main building at the Lake
Hoare campsite.

Picture #5: View of tents with Canada Glacier in the

background. Mine is the second from the left!

Our next stop was the Lake Hoare campsite, which is located on the western side of Canada Glacier and on the shoreline of another closed basin lake with the same name (Picture 4). The lake is fed by Anderson stream, which is the second stream I will be focusing on for my study.  The stream is sourced from glacial melt and will likely be one of the most scenic rivers I have ever sampled.

Given the fact that I will be spending at least a week at this campsite, it was important to learn the rules of the site itself as well as my responsibilities for maintaining it. The camp consists of a series of tents which surround a couple of small common huts, which are used for eating and conducting experiments.  There can be several different scientists staying at the camp during any given time, so I was showed which tent would be home for the next week. Fortunately, average January daily temperatures in the Dry Valley and McMurdo area hover around 32 degrees and I’ve brought along the appropriate cold weather gear.

The camp is overseen by Rae Spain, an Antarctic veteran with over 20 years of experience in the field, and her assistant Rene . Rae was recently featured in Food & Wine magazine http://www.foodandwine.com/blogs/
2014/11/6/how-to-cook-an-amazing-
thanksgiving-dinner-at-the-south-pole) due to her ability to make terrific meals with very limited ingredients. Even though the living conditions might be a little rugged, there will at least be good food!

Observation Hill

Picture #1: View of Observation Hill located on the south
side of McMurdo Station.

We initially planned to go into the field on Thursday but our helicopter was unfortunately experiencing mechanical issues. This is a bit of a bummer as we were supposed to take a reconnaissance trip out to the Dry Valleys to look for an ideal location to conduct my experiments.  There is also a two day moratorium on helicopter travel due to a New Years vacation for staff members so the trip will have to wait until Sunday. It’s a little frustrating but can definitely be expected as things don’t often go as according to plan and you just have to roll with it.

Picture #2: This memorial cross located
at the top of Observation hill was erected
in 1913 in memory of Robert Falcon Scott
who died while returning from the South
Pole in 1912. 

Fortunately, there is plenty to do in the lab and this has afforded me some time to catch up. I also decided to take in a little of the local scenery by hiking to the top of observation point, which is a 754 foot (230m) hill located at the south side of the station (Picture #1). The hill itself is volcanic in origin and the trail to the top was underlain with loose cinders of a variety of sizes. While it meant having to carefully watch your step at times, the views at the top were definitely worth it.

There were plenty of sites to take in at the top, including a memorial cross for polar explorer Robert Falcon Scott (Picture 2). Scott was an British explorer who set out on an expedition to become the first individual to reach the South Pole. While he did reach the south pole on January 17, 1912 he found that he was proceeded by a Norwegian explorer Roald Amundsen. Unfortunately, Scott's party of five succumbed to a combination of the elements and starvation on their return journey. Scott used the area of McMurdo as his base of operations and the hut he constructed in 1902 is still located at the edge of town.

Picture #3: View of Mount Erebus to the North.

Another sight you can take in from the top is Mount Erebus (12,448 ft) (Picture 3).  Mt Erebus is also located on Ross Island (the same island as McMurdo) and is approximately 25 miles to the north.  It is the second highest volcano in Antarctica and has been technically considered active since 1972.

Picture #4: View of wind turbines which provide supplemental
energy to McMurdo Station.

Observation point also provided a great vantage point for three wind turbines used to provide supplemental power to McMurdo Station and New Zealand's Scott Base (located within walking distance)(Picture 4). Installation of the turbines was completed in December 2009 and they currently provide up to 15% of the electricity needs for McMurdo, and over 85% of the same for Scott Base. Given the main power source for both bases energy needs currently comes from diesel fuel (more on this to come later), these wind turbines will save the need for ~120,000 gallons of diesel fuel annually.

Picture #5: Panorama view of McMurdo Station taken from the top of Observation Point.

Finally, there were also some great views of McMurdo Station and the Transantarctic Mountains located to the west across of McMurdo Sound (Pictures 5 &6). Our field sites are located at the base of these mountains so hopefully will be heading in this direction in the near future.

Picture #6: Panorama view of the Trans Antarctic Mountains located to the west across McMurdo Sound.

Training, training, and MORE training!

As you might guess from the title there has been an abundance of training sessions over the last three days. The list is as follows: light vehicle training, recycling and waste, general fire and safety, environmental field training, MacOps training (communications while in the field), outdoor safety training, and field and support training. Whew!  All of this training coupled with spending time in the lab getting acquainted with instrumentation I will be using for the next month equals a busy couple of days.

While all of this training might seem like overkill at first, I've really grown to appreciate the thought that is put into all of these safety protocols. McMurdo is a small town which swells in size from ~150 during the winter to ~1,000 in the summertime. This large population change is largely due to the influx of scientists coming in from around the world to conduct a variety of experiments across the continent, and the fact that McMurdo is used a staging ground for these endeavors.  Many projects, such as my own, will require transportation by helicopter or plane to relatively remote locations. Therefore, preparing for sudden changes in weather conditions that might leave you stranded in the field for a couple of days is an absolute must! For example, even if you might just be planning a day trip, it is important to bring enough food and warm clothing to last for a couple of days in the event of an unplanned snowstorm. It is also imperative to have a multiple ways to communicate with those back at the base in the event of an emergency or if there is a need for additional supplies. 

Unfortunately, training doesn't leave you with many flashy photos. Therefore, I’ll leave you with this gratuitous photo of Weddell Seals sunbathing along a pressure ridge (or break) in the sea ice on McMurdo Sound. 

Happy New Year!

Touchdown!

(My apologies for the belated post, but there have been some delays due to training and lack of internet access)

Picture 1: View of my fellow passengers before takeoff.

Picture 2: View of the interior of the C-130.

Time for the final leg of the journey! Fortunately, the weather cooperated on the morning of the 28^th and we were given permission to board our flight. In addition to the scientists I met from the University of Colorado, we were joined by three scientists from New Zealand, two from China, and two from Japan making this a truly international endeavor.  Our plane was operated by a crew of five from the New York National Guard, which felt strangely fitting as I'm a native New Yorker myself. 

It took a little while to load the plane as we were not only carrying the our own luggage and scientific instruments but also some resupply for the McMurdo Station in Antarctica. However, it wasn't too long until we were in the air.

Riding on a C-130 was an experience unto itself.  The interior of the cabin was unfinished and a little unsettling at first (Pictures 1 and 2). At the same time, it was interesting to see a lot of the inner workings of an airplane that we don’t normally get to observe.  It was also the coldest flight I’ve ever taken due to the lack of cabin insulation so it was a good thing we were wearing our cold weather gear!

About six hours into our eight our flight, the view was nothing short of amazing. Small icebergs drifting in the ocean began to dramatically increase in size and soon we were observing large chunks of sea ice (Pictures 3 &4). This is the austral summer or summer in the southern hemisphere, and we just passed their summer solstice.
Given Antarctica is located below the Antarctic Circle, there can be more than 20 hours of sunlight 

Picture #3: View of increasing sea ice while approaching
Antarctica.

a day during the months of September to March, and for certain portions of the year (including now) the sun stays above the horizon for 24 hours a day.  All of this excess sunlight heats up the seasonal sea ice that forms during the winter months and initiates its melting.

Picture #4: View of sea ice extent around Antarctica

as of December 28, 2014 (Source: National Snow and
Ice Data Center).

Our destination, McMurdo Station, is situated on the coast of McMurdo Sound, which itself is part of the Ross Sea.  The base is located near the transition between permanent and seasonal sea ice on McMurdo Sound. The permanent sea ice is an extension of a glacier that floats on McMurdo Sound, is much of greater thickness (>250 ft), and does not melt during the summer months. As mentioned above, the seasonal sea ice will typically melt from year to year, although its spatial extent will ultimately depend on how warm it is that given year. With that being said, when looking for along flat runway to land a plane, you probably want to chose an area with thick enough ice to support the weight of an aircraft. Therefore, our pilots chose to land in and area called Williams Field, which consists of a snow packed runway situated well within the area of permanant sea ice in McMurdo Sound.

Picture #5: View of our plane on the Williams Field "runway."

The landing was incredibly smooth as we landed on retractable skis located on the bottom of the aircraft.  Upon landing, we stepped out onto the ice and what was the most surreal landscape I’ve seen in my lifetime.