Land is in Sight

Over the past two weeks (since the 24^th) we have been steaming from Bruce’s mooring site in the middle of the Southern Ocean, heading to Punta Arenas. After weeks of enduring the high seas of the Southern Ocean, we were able to see land for the first time yesterday when we entered the Straits of Magellan from the west, and we spent the day marveling at the beautiful fjords that lined our passage. Presently, we are at a fueling pier in Cabo Negro, about a two-hour steam from Punta Arenas, and we should be topping off the tanks within hours and heading to Punta Arenas where we will be setting foot on land for the first time in nearly two months.

Views from our journey through the Magellan Straits. Photo credits: A. Margolin.

It has been a great journey, beginning with two weeks in New Zealand, where I spent a few days kayaking in fjords that passing through the straits reminded me of, reminding me of a distant home that I used to have, if it was mine for only a moment. After spending those two weeks in New Zealand I met up with a group of about thirty new people, who would become my closest friends over the following two months during the TRACERS Cruise. We experienced many great things together, such as the flight from Christchurch to the Pegasus Airfield on Antarctica, running the 5K in the bitter cold with bright smiles, learning about katabatic winds and getting to experience their bite near the Drygalski Ice Tongue where we spent weeks sampling the Ross Sea. Another memory that I will never forget, and was an experience that I will likely never have again, was getting close to the emperor penguins on the Sulzberger Ice Shelf and helping Jerry with his work tagging the birds.

The TRACERS Cruise participants on the Sulzberger Ice Shelf. Photo credit: C. Riesselman.

Tackling the Chief Scientist. Photo credit: C. Riesselman.

Shortly after Jerry completed his work tagging penguins, I had an interview with him that I recently shared on this blog. One thing that he said to me in that process that I did not include in the interview I would like to share with you here, as a closing note to this blog. I had mentioned to Jerry how overwhelmed I was by the hundreds of photos of penguins that I had taken, not knowing how to sort through them and organize them. Jerry’s response was:

“A lesson that I’ve learned in working with these animals is that you wind up with hundreds and hundreds of photos of them—whether penguins or seals—it doesn’t matter. But when I look back at those photos, it’s the people that I wish I had photographed.”

Those words will stick with me forever.

As I look back at my photos, I realize that many of them are not of the cruise participants, but of the activities that we did. However, because of resources like this blog and the ship’s server that allows us to share our photos easily, I know that I will not forget these faces that have become so familiar.

On that note, I wanted to thank you all for following our blog and for allowing us to share these great experiences with you. We are all looking forward to getting back to our friends, families and homes, wherever they may be. Thanks again.

–Andrew

Sacrifices in the Name of Science

In the corridors of McMurdo’s Crary Lab building (a research facility for the advancement of Antarctic science) there is a permanent exhibit showcasing titbits of McMurdoan scientific history. It is a voyage that retraces the footsteps of men who came here with a strong sense of adventure. Many of the remarkable stories of Antarctica recount the sacrifices the first explorers, particularly Robert F. Scott and Douglas Mawson, made in the name of science.

The Worst Journey in the World, by A. Cherry-Garrard (a member of Scott’s second expedition), gives an example of the extremes these men went through to gather data. Edward Wilson, the biologist of the expedition, was convinced the embryos of emperor penguins would provide answers as to the evolution of ancient to modern birds. Due to the emperors’ reproductive calendar, the eggs had to be collected in the dead of winter at a nesting ground at Cape Crozier, some 60 miles South of Hut Point. To survive the cold the explorers spent the long winter in an ice-cave, with not much else to eat than raw seal meat. Even if relatively short, the voyage on foot and the terrible hardships endured by the team of intrepid Brits surpasses, in my opinion, many modern-day expeditions with more ambitious goals.

During their ill-fated trip to the South Pole, Scott and his 4 men collected 35 pounds of fossils.

“The three emperor penguin eggs collected by Wilson [the expeditions biologist and head of science] and his colleagues on 20 Jully 1911 are sill in the collections of the Natural History Museum in London. They were presented to the Museum in 1913 by Cherry-Garrard.”*

“The ‘Winter Journey’ emperor penguin embryos were cut into about 800 thin slices, stained, and put onto glass slides for microscope study. Their official scientific report did not appear until 1934, by which time ideas about bird evolution had changed.”*

“Ponting [the expedition photographer] took many intimate portraits of the men, here highlighting Cherry-Garrard’s youthful innocence. Cherry-Garrard lived to know that, sadly, his ‘Worst Journey’ for penguin eggs produced no major scientific advance. Even as the eggs were gathered, the penguin theory of bird evolution was gradually being discounted.”*

“Wilson, Bowers and Cherry-Garrard tuck into a well-earned meal back at Cape Evans, having endured some of the worst conditions on Earth in the name of science”*

Despite losing two of their companions and starving from cold and hunger, Scott and his party continued to man-haul the load of rocks (contrast this with Amundsen, who had no scientific agenda and dashed to the pole on ultra light sledges, pulled to and from the Pole by his team of dogs). Scott’s "rock solid data" was to be recovered along with their frozen bodies nearly a year after they perrished. One of these fossils was of Glossopteris indica, a Permian era (approximately 250 to 300 million year-old) beech-like tree. Glossopteris fossils had been found previously in India and Africa, so Scott’s discovery was a key piece of evidence supporting the existence of Gondwana and proved that Antarctica was once covered in temperate forests.

“… (from left, standing) Oates, Scott and Evans, with (sitting) Bowers and Wilson, display the British flag [at the South Pole, a little over a month after Amundsen and his three companions had claimed it for Norway]. The film was found at the Last Camp and developed later.”*

“Both Scott and Amundsen had similar overall routes to the South Pole, although the Norwegians’ Framheim base at the Bay of Whales was just over 100 kilometres closer [to the Pole] than Cape Evans.”*

“This rock contains a fossil of Glossopteris, a type of extinct tree-fern. The rocks that Scott and his Polar Party hauled back included fossils of Glossopteris.”*

On the walls of the McMurdo Station cafeteria there are posters of Yellowstone National Park. It is not hard to transpose these landscapes of tall, forested mountains and fast flowing streams to ancient Antarctica, in the days of Glossopteris.

Ironically, it was the opportunistically collected fossil not the penguin embryos that proved to be the major discovery, but Scott and his men didn't live to realize the significance of their find. 

–Geoff

*All images and captions were taken from the book Scott’s Last Expedition, by Steve Parker, published in 2012 by the Natural History Museum, London for the Canterbury Museum.

Double interview: Alejandra and Dany, cooks of the Nathaniel B. Palmer

I'm currently one of the scientists on the NBP-1302 cruise, where we all know the time of day based on what meal is coming next. There are two main chefs who work hard to cook us all these great meals. Ale works the night shift from 00:30 to 12:30, cooking breakfast and lunch. Dany works the opposite shift, from the afternoon until night, cooking dinner and midnight rations (mid-rats), a meal for people who work during the night shift on the vessel.

Being a cook on a research ship is something completely different than working at a restaurant.  Depending on the ship's destination, its number of passengers, and especially the duration of the cruise, the cook has to be creative with the ingredients he or she has available. They work hard with these ingredients, forming the menus and appeasing the vegetarians, not only for a couple of days but for months at a time.

Let's see what our cooks think about their special role on the Palmer...

–Gianluca

Link: http://tracers-nbp1302.blogspot.com/

Life at Sea in Antarctica: A Not-So-Technical Report

Cody on the Sulzberger Ice Shelf near Cape Colbeck, kneeling in front of a group of emperor penguins. Photo credit: S. Bercovici.

Seven weeks since leaving home and what a wild ride it has been so far! This is my first time in Antarctica and my first time ever at sea. The only past experiences I have had on a boat have been day trips, never overnight. The scenery throughout the trip has just been truly incredible and far surpassed what I even imagined. Cathedrals of icebergs, penguins, seals, whales, aurora australis, and unreal sunsets, to name a few just off the top of my head.

Sunset behind the Palmer. Photo credit: A. Westman.

Life on the boat is surprisingly warm and comfortable compared to the harsh conditions outside. Whenever we are working outside on the deck for an extended period of time we are always fully suited in work gear that keeps us plenty warm. For a few weeks we worked outside for 2-3 hours a day deploying plankton nets either towed behind the boat or towed vertically off the side depending on the ice cover. The nets have a mesh pore size large enough for single cell phytoplankton to pass through, but small enough to capture zooplankton and anything larger that happens to be in its path. Net tows are just one of the many things that the Old Dominion crew (Alexander, Melissa, and I) is working on, but they are fun for everybody because the results are instantaneous and visible, as opposed to intangible results from a machine measuring a water sample. Some of the organisms we have caught in the net tows include copepods, amphipods, krill, ctenophores, chaetognaths, fish larvae, pteropods, and even a few larger fish.

(From left to right) Me, Tommy and Alexander deploying the large plankton net. Photo credit: B. Huber.

Fresh net tow sample with lots of fish larvae. Photo credit: B. Huber.

A closer look at a net tow sample. Photo credit: C. Garrison.

We caught a monster! This is an ice fish, caught near the coast of Cape Colbeck. Photo credit: A. Bochdansky.

We end up working long hours every day, but with pleasant breaks in between. The meals are definitely better than I expected and are always something to look forward to. There’s also not much of a concept of time. I rarely know what day of the week it is much less the day of the month. The only thing I’m aware of is that lunch is at 11:30, dinner is at 17:30, and mid rats (midnight rations) is at 23:30! Lots of music and a few good books have also been very enjoyable during any down time that I have. There is also an insanely big collection of movies and tv shows, new and old on board along with several big screens, surround sound, couches and recliners. Not too shabby at all!

The 02 Lounge, where there are frequent viewings of Breaking Bad, Modern Family, Community and a variety of movies. Photo credit: A. Lee.

The 03 Conference Room, where our scientific meetings and Marine Biogeochemistry class are held, along with occasional showings of Gilmore Girls and Downton Abbey. Photo credit: A. Lee.

About a week ago we arrived at an unfamiliar place called Cape Colbeck in hopes that it would be a hotspot for emperor penguins. One of the teams of scientists on board that work mainly with penguins had 21 tags to place on emperors in order to track their activity. Once we wedged our vessel into ice thick enough to walk safely on, the entire crew was able to get off and enjoy the feeling of land (actually sea ice, although, it felt like standing on land) for a few days. It turned out to be an extremely memorable part of the trip. We all enjoyed passing around a soccer ball and a football, building an ice fort, and exploring the area on snowmobiles with sleds dragging behind! Pretty awesome stuff. Day 2 at Colbeck we awoke to the sight of emperor penguins everywhere around the boat and our ice fort! At one point during the day we counted over one hundred penguins visible. The weirdest part is that the penguins had no fight or flight instinct whatsoever, simply curious and clumsy creatures. Some even came within arms distance for a moment. Needless to say, deploying 21 penguin tags was very easy.

Hans and I playing some futbol our first night on the Sulzberger Iceshelf, with people tagging penguins in the background. Photo credit: A. Bochdansky.

Exploring the Sulzberger Ice Shelf. Two snowmobiles were used for Jerry’s group to tag penguins, but only a handful of us were able to assist in the tagging of the birds. Since we weren’t all allowed to go out on the snow mobiles for bird tagging purposes, snow mobile “tours” were arrange so everyone was able to take a couple hours away from the ship, to enjoy the beautiful Antarctic scenery. Photo credit: R. Dunbar.

Penguin invasion! Many of us no more than fifty feet from the Palmer, enjoying the numbers of emperor penguins that would stop by to explore their curiosity. Photo credit: C. Garrison.

Every day at sea the weather and scenery are different. We’ve experienced super thick ice covering the ocean as far as the eye can see, water freezing before our eyes forming a slushy surface layer and fresh pancakes, and the water has ranged from crystal clear blue to cloudy water rich with phytoplankton. Standing upon the bow gazing across the horizon I often can’t stop thinking about the fact that I am standing virtually upside down on the bottom of the earth. Such a drastically different orientation than that of friends back home at that very moment. And then on other days you can’t distinguish any sort of horizon at all. Surrounded by thick sea ice the sky is often so white that you can’t tell where the snowy landscape ends and where the sky begins. The extremely harsh conditions of this environment make it clear that humans are really not supposed to be in this place ever. Modern technology has made it possible to study the rich ocean life present here all while enjoying the comfort and warmth of the NB Palmer vessel. It is truly an experience I will never forget!

Making our way north, out of the Ross Sea on March 3^rd, by breaking our way through some thick sea ice to reach the lead ahead. Photo credit: A. Margolin.

Frozen boat. An iceberg and the sides of the Palmer covered in ice formed by the freezing of seawater. Photo credit: A. Westman.

A big shout out to all my family and friends back in Virginia! Miss you guys and hope all is well.

–Cody

“Nuts” (pronounced ‘newts!’) in the Ross Sea

My name is Meredith and I am a first year graduate student studying biogeochemistry in the Hansell Lab at the University of Miami (RSMAS). Lucky for me, my first significant research cruise has brought me to a region of the world more mysterious and wonderful than I could have ever imagined!

Terra Nova Bay. Photo Credit: G. McDonald.

Emperors on Sulzberger Ice Shelf near Cape Colbeck. Photo Credit: R. Dunbar.

Sunset over pancake ice. Photo credit: M. Jennings.

Cape Colbeck Emperors checking us out at Sulzberger Ice Shelf. Photo Credit: A. Westman.

However, I frequently have to remind myself that I did not travel all the way to the edge of the world from Florida just for amazing sightseeing! I spend a portion of my time learning from other research groups on board as a crash course in 'Oceanography 101' but I also have my own responsibilities in the lab. Primarily, I collect seawater samples from a device that collects water from great depths (called a CTD rosette) to analyze for “nuts” or nutrients (namely phosphate, silicic acid and nitrate), which are essential players in the biogeochemistry of the Ross Sea.

Biogeochemistry is the study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment. It deals with 1) how biological and geochemical processes affect organic matter and its principle components (carbon, nitrogen, phosphorus, etc.) in the biosphere, and 2) how chemical elements and compounds (such as nutrients) cycle between the living and non-living parts of an ecosystem.

Acting as biogeochemical fingerprints, nutrient distributions can help us explain and characterize properties in the marine environment such as phytoplankton productivity and seasonal turnover of the water column. For example, we expect lower nutrient concentrations in the surface layer because available nutrients have been consumed by phytoplankton to fuel a summer bloom. Below the surface layer, concentrations of nutrients are typically higher due to the recycling of organic material by bacteria and should be similar to the nutrient pool available prior to a bloom. Therefore, we can get an idea of the flux of nutrients during phytoplankton blooms. If none of this is making sense, just think of nutrients available to phytoplankton as fresh chocolate chip cookies available to a bunch of graduate students (and Roberta)...

A schematic of the biological pump in action! Image from Ocean Biogeochemical Dynamics, by Drs. Jorge L. Sarmiento and Nicolas Gruber, used in the marine biogeochemistry course that my advisor Dennis Hansell is teaching us aboard the Palmer.

Analyzing the concentrations and fluxes of nutrients will help us understand the broader picture of the biological pump, which is the cycle of organic matter production, its export from the surface ocean as sinking particles (downward transport), and finally its remineralization (conversion from organic carbon to dissolved CO₂). On board, I have been analyzing silicic acid in seawater using a reaction that produces a beautiful blue color in the presence of the nutrient by adding a few chemicals [an acidified molybdate reagent and a reducing mixed reagent (electron donor)].

This blue acidified and reduced complex displays a max absorbance at 810 nm. Photo credit: M. Jennings.

After letting the blue color develop for a couple hours, I use an instrument called a spectrophotometer to detect the light absorbed by this blue solution to calculate silicic acid concentrations after calibrating the instrument with known concentrations of the nutrient. A similar method using a colored chemical complex is also used to analyze phosphate (performed onboard by Sarah).  Nitrate, the third nutrient we are considering, requires a completely different method for analysis, which we will perform back in our lab in Miami.

Amanda and me (front right) working hard at the spectrophotometer. Photo credit: A. Lee.

The Ross Sea is an extremely productive system, making it a very interesting place to study (if our pictures of the gorgeous views and magnificent animals haven't already convinced you!). Even after intense phytoplankton blooms, the nutrient concentrations are much higher in these surface waters than in many parts of the world. Our proposed work has been very exciting to watch unfold as we are discovering what is happening to the system's biogeochemistry at the end of the productive season. I feel fortunate to be a part of this process and am excited to learn more in the weeks to come!

Party in the ice fort (complete with hot cocoa)!  Photo credit: D. Mucciarone.

–Meredith

The Lab Van: Bringing a little bit of Charleston to the Ross Sea

When research brings us scientists out to sea (as it frequently does) one of the biggest considerations is the logistics of bringing our equipment with us. This includes a lot more stuff than one may realize. In addition to consumables (thousands upon thousands of sample vials and tubes, bottles, reagents, preservatives, pipet tips, zip ties, bungee cords, chocolate, sodas, coffee, etc.) we also have expensive, fragile, and often quite bulky instruments. We can either box these items up and ship them in several installments, or we can simply send an entire lab already stocked. The DiTullio lab group from the College of Charleston has the capability to do the latter.

Our mobile lab (or lab van for short), which we have nicknamed Cougartown after the College's mascot, is a fully functional flow cytometry and gas chromatography laboratory. The van’s construction is based on a standard 20ft shipping container so it is roughly half the length of a tractor trailer, which makes it easier to send anywhere in the world. It was custom built according to specifications laid out by one of our research associates, Dr. Peter Lee. He and I spend the majority of our day (a 12-20 hour day, not a regular 9 to 5’er) in Cougartown, and it suits us just fine, though the interior is not as spacious as you may assume.

“Scientific Laboratory?” More like “Home Away from Home.” Photo credit: J. Kendrick.

Cougartown on the back deck of the NBP during a balmy Antarctic day. Photo credit: P. Lee.

Dr. Lee (Petey), a seasoned and accomplished chemical oceanographer, runs our cryogenic purge and trap gas chromatograph. Using this instrument he extracts dimethylsulfide (DMS) and dimethylsulphoniopropionate (DMSP) from seawater and measures their concentrations down to nanomoles (10^-9) per liter. These compounds are extremely important products of cellular and chemical activity in the ocean that have a disproportionately large effect on the composition of our atmosphere and the regulation of earth's climate. I'd get into specifics, but that's a blog post in itself. Suffice it to say, life would have a hard time existing without them.

My job in the van is to run our high-speed sorting flow cytometer, the Beckman Coulter MoFlo Astrios. MoFlo is short for Modular Flow Cytometer, sorry if that disappoints anyone, it did me.  A sorting flow cytometer (or just “the flow”) is a lot like one of those coin-sorter banks you may have had as a kid. The difference is that the flow sorts microscopic particles at rates of up to tens of thousands of particles per second. When a sample is put into the sample chamber it is pressurized, run through a special nozzle, and shot straight down in a stream 70 microns wide (about the size of a human hair). Cells travel down the stream in single-file past 3 lasers of different wavelengths. As the cells hit the laser beams they scatter the light in several directions. The direction and degree to which they do this gives us an idea of the relative size of the cells. Several compounds within the cells will fluoresce in response to the lasers as well (think of how things glow when you stand in a black light). The wavelengths and intensities of the fluorescence are collected by the instrument and plotted on graphs against one another allowing us to tell different species apart based on how they “glow.” This is a little more difficult in the Southern Ocean as a lot of the phytoplankton species are similar sizes with very similar cellular make-ups. The flow has a few tricks it can do to get around this problem, but I'm not writing a technical essay here.

So how does it “sort” the cells? That's where it gets really cool. A special crystal in the nozzle vibrates the stream causing it to break into distinct droplets with one cell per droplet.  Based on criteria that we give the instrument, it attaches an electric charge to the droplets, which are then run past two powerful electromagnetic plates. When a droplet you want passes the plates, a small electric pulse literally pulls that droplet out of the stream and drops the cell directly into a test tube under it. The MoFlo Astrios can sort into 6 different test tubes simultaneously, meaning those magnetic plates can turn a single stream into 7 streams (the original + 6 more).

Here's simplified diagram of how the flow works. Pretty cool, huh? Reprinted with permission of Beckman Coulter.

By sorting seawater we can separate the phytoplankton community into its constituent species after which we can start cultures of new strains that may not have been isolated before. We can also use the sorted samples to run experiments, or perform species-specific analyses that give us more detailed information than analyzing whole seawater. After a month at sea I've turned dozens of seawater samples into hundreds of sorted cell cultures. 

That's what we do in the van, so what's it like to spend pretty much all our time in there? There are a lot of pros and cons to bringing your lab with you. On the plus side, setting up your workspace at the beginning of the cruise is easier since it's mostly set up already. While everyone else is unpacking boxes, putting things together, and strapping things down (everything has to be tied down at sea) we just have to turn our instruments on and calibrate them since we did all the setting up and tying down months before the cruise. We also have our own soundsystem and since there's only two of us in the van, there's very little argument about what kind of music to play while we're working. Another great thing about working in the van is that our workstations are literally the same two we use back in Charleston so it's like taking a piece of home with us when we're so far away.

Petey and me at our workstations. Photo credit: A. Margolin.

That last one is kind of a pro and a con, since it limits the new experiences you have. It also isolates you somewhat from the rest of the science team. Two months at sea is long enough that you still get to know everyone, but you miss out on a lot of inside jokes and pictures (and you frequently don't get told when they're making liquid nitrogen ice cream in the galley). A more technical problem is that the flow is pretty sensitive to vibration, and the van is sitting on the back deck directly above the ship's propellers. When we chew up big chunks of ice it shakes us pretty violently and that makes work a lot harder. Being on the back deck also means going between the van and the rest of the ship takes you across a weather deck (i.e. outside). That's kind of nice on tropical cruises, but Antarctica is quite cold and the back deck is prone to boarding seas and changing weather. You never know if you'll be walking out into snow, icy winds, or frigid, ankle-deep water the next time you have to go to the head. In all honesty though, that kind of adds to the sense of adventure that we all get out here.  Speaking of adventure, here's what it looks like after a wave washes completely over the top of the van (with us inside) in super cold weather.

It might be hard to see, but the whole thing is covered in about a ½ inch of ice. Photo credits: P. Lee.

What isn't nice in tropical climes, but isn't so bad here, is that all the electronics generate a lot of heat. Even when the outside temperature is 20°C degrees below zero (Like in the first photo up there) we have the air conditioner running to keep it at room temperature!

Cougartown has been our home base for two cruises so far and apart from a few minor issues here and there it's worked out great. The freedom and comfort it affords us is definitely worth any slight inconveniences. We also make improvements to the van and to our instruments in between cruises so it gets more and more comfortable and functional all the time!

Even an instrument like the Astrios needs a little fixing now and again. Here I am replacing some components in the electronics rack. Photo credit: P. Lee.

–Jacob

Give Us the Water! How Much? All of It!!

Well, just how much water IS there to be had in the Ross Sea? There are approximately 265,000,000,000,000,000 liters*.  Did that number go in one eye and out the other? It did for me. Let’s just say that’s a lot of water and scientists want to know about all of it—where it came from, where its going, the chemistry, the biology, temperature, salinity, floating particles, etc. etc. etc….

There are two issues I’d like to explain to you:

1.              Where do you decide to collect this water?

2.              How do you collect it?

Just think, after reading this blog you’ll be that much more prepared for Thursday Night Trivia or to impress your friends at a dinner party!

Where oh Where?!

Obviously we cannot take ALL of the water in the world and measure its properties.  We can, however, do our best to characterize as much of it as possible. In fact, all over the world cruises like the one we are on are out collecting information about the oceans. Using software, like Ocean Data View, scientists can have a pretty good idea of what is going on. All of these blue dots are locations where water was analyzed.

A map that Allison made using the GLODAP dataset with the program Ocean Data View (ODV), which she learned how to use in a course Dennis is teaching us aboard the Palmer, entitled Marine Biogeochemistry.

This is a map of the Ross Sea, which displays locations where samples were collected during TRACERS. Map credit: A. Lee using ODV.

How do scientists even begin to know where to choose to take samples? Let’s explain this with an analogy we might all relate to:

If you know that your dog hid your favorite pair of slippers in the backyard and you wanted to find them, where would you look? Would you start in one corner of the yard and work your way to the other corner in rows? Probably not. You wouldn’t start your search aimlessly looking everywhere, that would take you all evening and you don’t want to miss your favorite showing of The Simpsons! You’d have some sort of plan and rule out certain areas first. You would look for dirt that seems to have been dug up, you may look under the dogs favorite corner, you may even look under the porch. If you knew your dog’s behavior well enough, then you might even know exactly where she’s hidden your slippers!

Scientists do the same thing with oceanography. We pour over charts and based on the knowledge of where water moves, how water moves, the topography of the ocean bottom (bathymetry) and the location of living organisms such as algae, scientists choose these certain “hotspots” and start there.

We have drawn a line that we would like to investigate. In the upper right corner is a photo of chlorophyll (or algae) from satellite data. Photo credit: A. Lee.

I think it is time to introduce the HOW we collect the water:

This is the old-school method: Tossing the Pail. When you need deeper depths you simply add more rocks or weight to the bottom of the bucket so it sinks. Photo credit: A. Margolin.

Hmm something doesn’t seem right about this method. It’s the modern age! Isn’t there some sort of fancy technology we can use for this? Why, yes, yes there is. But this requires us to dive in to some terminology.  Let’s cater to you visual learners:

This is the CTD rosette that we use to sample the ocean. Photo credit: A. Lee.

The Niskin bottles hold 12 liters of water each and are arranged in a circle called a rosette. Commonly, we just refer to the entire thing as a CTD but technically, a CTD is the little package of sensors attached to the Rosette that measure Conductivity (Salinity), Temperature and Depth. The information about the salinity, temperature, and depth, as well as fluorescence of chlorophyll (algae) and oxygen levels are sent to the ship as we lower the CTD package to the bottom of the ocean.

On the left, Rob and Kevin look at the CTD data as the rosette is lowered. On the right, the CTD data is displayed on the computer. Photo credits: A. Lee.

We can look on the screen as the profiles are being recorded and decide on what depths the bottles should close at as the CTD comes back up to the surface. Once the CTD reaches the bottom, one of the ET’s (either Sheldon or Kevin) will push a button to close Niskin bottles at the desired depth, collecting that water for us to analyze in our various laboratories on the Palmer. 

The CTD rosette being deployed. Photo credit: A. Lee.

Each time this “CTD” or “Rosette” goes in to the water it is called a “cast”. Over the past 33 days, we have taken 135 casts. We collect seawater about 4.5 times a day (in addition, each time it enters and exits the water we have to do 25 pushups). That doesn’t seem like a lot but considering we have to actually DO something with all the water once we collect it, time flies and its already time for the next cast.**

Now that the CTD is on deck, everyone wants the water from it. Before anyone can take the water, a “water budget” is created so there will be no fighting for who goes first. Before the cruise started, scientists sat down to discuss the volumes they needed based on the types of studies/analyses they intended to do. Those people collecting for gases go first because once the volume leaves the Niskin, air fills the top and can change the gas composition inside. Everyone goes in order and if you cut in line you get elbowed.

Santiago patiently waits just outside the Baltic room while (from left to right) Dave, Rob, Cassandra and Petey sample for gases. Photo credit: A. Lee.

Once everyone has taken their share of water, we each head back to the lab to begin our analysis or collection method to store it for later analysis.

Dave taking a break from eating desserts to do some POC’ing, Roberta’s filtration setup for microbes, Rachel in the lab ready to analyze some phytoplankton, and Meredith preparing for nutrient analysis. Photo credits: A. Lee.

To read more about exactly what is done with the water by each scientist on board, stay tuned to more blog postings!!

–Allison

PS – Check out Cassandra’s new National Geographic post on TRACERS!!! http://newswatch.nationalgeographic.com/2013/03/12/fighting-for-the-last-tomato-surviving-a-field-season-in-antarctica/

*Yes, I actually calculated that with the help of Kim Goetz and GIS software. The Ross Sea is a small blip on the map and water is circulating in and out constantly so there is no real fixed volume.  

** Now that you know some terms I want to throw some more calculations at those of you who like to nerd-out. Just hold my hand and follow me: If our Rosette has 20 Niskin bottles that each hold 12 liters, then that is approximately 240 liters per cast that we can take. If we were to actually take all of the water in the Ross Sea averaging 4.5 casts a day it would take us ONLY 245,000,000,000,000 days or 672,000,000,000 years! So ya, moral of the story, thank Bessy for software that helps analyze ocean data because there is no way to sample all of the water in the Ross Sea much less the entire global ocean!