Thursday, September 21, 2017

Running South

The aftermath of a wave over the back deck. The float was thankfully still in its
plastic bag. The tape holding the cardboard box closed dissolves after a few
minutes in the water, releasing the float into the ocean (or wherever it is at the time).
We've spent this week in the famous Roaring Forties, named for the westerly winds that are prevalent in this part of the world and often keep the seas high. We left Gough Island (40.3 degrees South) and headed south on what is called 'the buoy run." The weather service onboard the ship deployed drifters that will track currents and weather conditions, and the oceanography team deployed a total of four floats. This included two for the SOCCOM program, floats named Titans and Zora.

The Roaring Forties were true to their name and kept us all rocking and rolling. It's easy enough to adapt when you're walking through a hallway - every once in awhile, a perpendicular step on the wall may be necessary. "Keep one for the ship" means always keep hand free to grab a railing. Less easy is the task of eating in the dining room when everyone's chair is shifting left and right, and the peas on your plate are following suit. The hardest may be to sleep through uneven rolls, a few which threaten to spill you right out of bed. The movement of the curtains on their metal track, the apple in your drawer (don't tell, we're not supposed to have food in our rooms) thumping back and forth with the swell. That being said, I've done alright. Thankfully I can sleep through a lot, and generally sleep better at sea than on shore. But from the grumblings at breakfast and the lack of people socializing in the evenings, I can tell that some of the others have had trouble.

UW technician Rick readied Zora to be boxed up while back
 in Cape Town. The sensor visible at the base of the float
measures chlorophyll fluorescence and backscatter, from
which zooplankton populations can be studied. 
Thankfully the floats were not put off by the weather - both were deployed smoothly and are dutifully at work gathering data. Zora (named for the species of fish people in the video game Legend of Zelda) was deployed at our furthest south station, 47.5 degrees. I was surprised at first to hear that this was the highest latitude some of the scientists onboard have ever been, but then I thought about it and realized it's likely a result of living in the Southern Hemisphere. The only land below 45°S is in Patagonia. Whereas in the Northern Hemisphere, 47.5° runs pretty much along the border between the United States and Canada. All of the UK and half of Europe is above that latitude, as well as most of Russia.

The ship is returning to Gough Island, where there's a few more days of work for the helicopter pilots to do. We did the buoy run ahead of schedule to avoid a storm. Which, considering how high the seas were already, was probably a good idea. It's satisfying to have gotten the work done, and sent the floats off safely. Their work has just begun!

My attempt at drawing a Zora.
Titans, pictured with Cape Town and
Table Mountain in the background.
More on this float in a future post!


Sunday, September 17, 2017

A Float Between Islands

The ship's bosun and his mates stand ready to lower Pixel off the stern of the ship.


Yesterday we deployed another float, our second of the six planned for this cruise. Adopted by Stanford Online High School in California, the float is named Pixel, after the school's mascot.

Pixel was deployed at 06:00 local time, which right now is the same as GMT (Greenwich Mean Time, also referred to as Zulu time). We crossed the zero (also called prime) meridian a few days ago and are now in the West longitudes instead of East. It was still dark out, so not quite as photogenic of an operation as the one from last week, but it went smoothly and that's the important part.

We deployed Pixel during our transit between the islands of Tristan de Cunha and Gough, and it should provide some interesting data. The South Atlantic Subtropical Front crosses through this passage, separating two very different water masses from each other. Oceanographers are able to tell the origin of water throughout the world's ocean using many of the properties collected by these floats, including salinity, pH, nitrate, and dissolved oxygen.

The hope is that Pixel will drift back and forth across the boundary a few times, profiling the water column on each side. It would be great to see plots from this float providing a direct comparison of the tropical-influenced water mass on the north side and the polar-influenced waters on the south.

As I mentioned in a previous post, the scientist studying rockhopper penguins can see the difference in the population that lives on either side of this front as the different water masses support different prey species. She got off on Nightingale Island yesterday, and I will make sure to ask her more questions when the ship picks her up again in a few weeks.

Thankfully Pixel is a simple mascot, so didn't ask too much of my limited artistic skills. 

Pixel is just the latest float to be deployed for the SOCCOM project. Also underway right now is the GO-SHIP P6 cruise, crossing the Southern Pacific Ocean from Sydney, Australia to Valparaiso, Chile. They are also conducting CTD casts and deploying floats, with names like Floaty McFloatface and Magic School Bus. You can follow their blog here.

Wednesday, September 13, 2017

A Day on Tristan da Cunha


Agulhas II off the coast, with the volcano rising in the center, and St. Mary's School (for kids age 3-16) on the right.

The weather was nice today as the ship approached the island of Tristan de Cunha. Passengers were offloaded by helicopter, and then there was time for us scientists to take a trip over as well, being ferried back and forth by the ship's small boat. Tristan is the most remote inhabited island on the planet, 1,500 miles from South Africa and 2,100 miles from Brazil. There's only 260 residents, many of whom are descendant from the same 15 settlers. Even the dogs we saw seem to be from the same family. There's no hotels, but we were able to get our passports stamped and send postcards (which will come back to South Africa on our ship in a few weeks). I recommend reading the Wikipedia entry, it's fascinating. It was quite a treat to get to step on land and see such a unique place. My roommate Caitlin, a scientist studying microplastics, and I walked through town and then out to the lava fields (there was an eruption in 1961) and then to a rocky beach. We saw skuas and albatross by the dozen. I wish we'd had a geologist with us, the rock formations are gorgeous. We had a few hours to explore, and it really did feel like being an explorer as I reckon only a few thousand people have ever been to this place. It was an experience I'll never forget.


Past the lava fields is a rocky beach, with Tristan skuas flying in the breeze.


As we returned to the ship, a Tristan albatross (once thought to be a subspecies of wandering albatross) flew overhead. 

Tuesday, September 12, 2017

Weather Balloons


Weather balloon and instrument package,
with me for scale.
Weather and a few other delays dictated that we put off deploying the next two SOCCOM floats until the return trip. So I've had a few days with nothing much to do, but I'm trying to keep busy by chatting with the other science groups and learning about their projects. 

There's members of the South African Weather Service onboard, some of who will stay on the ship while others get off and work from the islands. Every night, a weather balloon is deployed from the ship - and tonight I went to observe and take pictures.

The balloon is filled with helium on the ship, but on land they're usually filled with hydrogen. A package is attached that measures temperature, dew point (from which humidity can be calculated), and wind speed and direction using a GPS. Last night's balloon went to 21 kilometers before popping. I didn't stay long enough to see how high tonight's went, but I did check out the real-time data plots (see picture below).

From land stations like on Gough Island, a balloon is launched twice a day at roughly the same moment. This global network provides data to forecast weather and track storm movements. It's easy to take for granted that an app on my phone will tell me the forecast, so it's very interesting to see in person how that data gets collected. 
Locations of weather service stations worldwide.
The ascension rate (green), temperature (red), and dew point (cyan) data is plotted in real time.
The calculated humidity (dark blue) spiked likely due to the balloon going through a cloud layer.

Monday, September 11, 2017

Transporting Scientists

Agulhas II will offload scientists and gear
at Tristan, Nightingale, and Gough Islands.
A number of science talks were given today in the ship's auditorium. It turns out that there's multiple field projects on Tristan, Nightingale, and Gough Islands that are being staffed by people on the ship. I'll try to add some figures from the talks, and pictures of the scientists at work if possible.

Antje Steinfurth is on her fourth trip to Tristan Island to study the Northern Rockhopper penguin population, called pinnamins by the locals. 85% of the population breeds on Gough and Tristan Islands. The two islands are 380 kilometers apart (236 miles), but there's a front that crosses through the ocean there that creates a very different environment around each, including a temperature gradient that influences the dominant food source for penguins. I'll see this for myself in the next few days, and we're specifically deploying one of the SOCCOM floats right along that oceanographic boundary. In 2011, an oil spill from a ship that ran aground on Nightingale Island created an environmental disaster and seriously affected the beloved penguins (see more pictures here). Since then, the locals have partnered with government agencies to support scientific studies to monitor the population. Some have been micro-chipped, much like a cat or dog, so that they can be tracked. Antje has set up a scanner that the penguins have to cross in order to get in between the ocean and the nesting grounds. So it counts each individual as they go back and forth.

Subantarctic fur seals live on the islands
by the thousands. 
Greg Hofmeyr of the Port Elizabeth Museum is studying layers of fur seal teeth, which grow like tree rings as they age, in order to determine their diets. The seals breed on Tristan Island, and his team will be aboard for three weeks to collect skulls and teeth from any dead seals they find there. Last year they collected got 90 specimens, so I'm picturing a big bag of them being brought by helicopter when we return to the island next month. Recent specimens will be compared to those in museum collections to determine how changes in the environment has affected their diet over the last 50 years.

There's also a French project called Enviroearth that uses monitoring stations on remote islands to detect nuclear explosions. There are arrays of sensors on the ground that pick up seismic waves and some in the air that can detect even the smallest amount of radioactive isotopes. After the madness of the 20th century, an international treaty in 1995 ended nuclear testing. Since then only six detonations have happened (looking at you North Korea). The scientists are also installing renewable energy in the form of solar panels and heaters on houses on the island.

The South African Weather Service has scientists onboard, a few of who will get off at Gough Island to spend a year taking measurements at the station there. It's been monitored for nearly 60 years and the station is getting old, so one of the technicians is stopping at Tristan Island in order to assess relocating the weather station there. Because of the previously mentioned environmental differences between the islands, this raises questions about data continuity. A few of the weather service employees will stay on the ship for the whole trip. They report weather conditions every three hours, which is used to help the captain make navigation decisions, and the data goes to ground truth climate models based on satellite data. On the run south after we leave Gough Island, they will deploy weather balloons and drifting buoys that will further add to the data set.

So there's a lot going on! This is in addition to the 10 scientists who will get off to spend a year on Gough Island, as well as a married couple who will study land birds on Nightingale Island, completely cut off from the rest of the world for six months. And here I thought I lived remotely for long periods of time in order to do science - all of a sudden this five week cruise doesn't seem like such a sacrifice.

Sunday, September 10, 2017

Marine Mustang begins her mission!

Marine Mustang makes it safely into the ocean.
We deployed our first float on Saturday! Its nicknamed Marine Mustang after being adopted by J.C. Parks Elementary School in Indian Head, Maryland. Deployment went smoothly. Though I usually describe my role in all this as “I chuck floats off the ship and then run analyses to calibrate the sensors,” there is absolutely no ‘chucking’ allowed! Lovingly, gently, carefully it is lowered into the ocean. The sensors and housing may be engineered to withstand freezing temperatures and crushing depths, but a fall could prove fatal. The ship's bosun and his mates did a great job.

It's a little less photogenic this time around since each float is packed up in a cardboard box. This prevents any banging of sensors against the ship during deployment. Tape that holds the box together dissolves after a few minutes, releasing the float. I've heard that this one has checked in, and even gone on its first dive to 2000 meters and reported back with data.



The float before it went in the box. I'm quite pleased with my drawing of a horse actually.




CTD deployment, as seen from two decks up.












The CTD cast came before the float deployment. On the Agulhas II, a giant door along the starboard side opens up and an A-frame lowers the CTD into the water. Once it's back on deck, we deploy the float and then sample the water brought back up from various depths between the surface and 2000 meters.

We have had to delay the second deployment due to bad weather. Since yesterday's blue skies and calm seas, both wind and waves have picked up. We'll deploy the float at that location on our way back, in about four weeks. That's the advantage of a cruise that's going out and back.

Below are a few more pictures. More to come in future posts, thanks for following along!


Bon voyage, Marine Mustang!
J.C. Parks Elementary students learn how to reduce their use of plastic,
which is a huge threat to the health of the world's oceans.





Wednesday, September 6, 2017

Setting up in Port

The floats take in a lovely Table Moutain view.
There's always a loading period before a research cruise where the ship is in port and the science party rushes around getting everything prepared. I've been in Cape Town for a few days now and it's been very busy! I will be analyzing seawater samples for nutrient and dissolved oxygen concentrations onboard, so I have a lot of gear to set up. Thankfully since there's only a few scientists on this cruise, I have plenty of lab space. After making sure all my shipments arrived safe and got onboard, I started unpacking. The lab didn't have power or water the first day, so there was only so much I could do.

By the afternoon of day two, that was up and running so I could test each machine and start making reagents. I had to make a trip to a hardware store to get supplies for securing everything on the lab benches (tables) so it won't fly around if/when we hit some weather. Today (day three) I realized that the power converter I was using for the filtration rig wasn't strong enough and had blown a fuse. Most of our equipment can be used with either 110V (US) or 220V (everywhere else) power, but there's a few things that have to go through a transformer. So I spent a few minutes panicking and then called the chief scientist, who within a matter of minutes had secured me a replacement pump and transformer from a lab at the University of Cape Town. A taxi ride and an hour later, I now have three working pumps instead of zero!

Technician Rick enters the matrix.


I also helped the technician from University of Washington prepare the floats for deployment. He went through a whole series of tests to make sure all the instrumentation wasn't damaged during transport (see photo at right). This involves bringing them out on deck so they can communicate with a satellite, which provided some lovely photo opportunities as well (photo above).
Each float has been adopted by a school, so I wrote the name and drew a few designs on them. We're deploying them in cardboard boxes this time around, so I'll probably decorate those as well.

R/V Agulhas II is quite a ship! It's the biggest I've ever worked aboard, and thankfully has color-coded decks like a parking garage (the lab is on purple fish, or deck 3). There are many differences I've noticed already from the U.S. research vessels that I'm used to - including served meals (rather than cafeteria style) to which men have to wear collared shirts, tea time, a bar (two actually), and the presence of passengers instead of just crew members and scientists. I'll write more about that in an upcoming post. Every ship has its own vibe, and I'm interested to learn more about this one. The South African people I've met so far as friendly and helpful, so that bodes well. Last year I was aboard an Australian research vessel deploying SOCCOM floats and shared that experience in a blog post. 
We leave tomorrow, hope you'll follow along!

Thursday, August 31, 2017

Next Cruise, on a South African Icebreaker!

Stock photo of Agulhas II. It's unlikely that we'll see ice,
we're only going south to about 48°
Hi, my name is Melissa Miller and I'm a marine technician at Scripps Institution of Oceanography. I'll be aboard the next cruise that is deploying SOCCOM floats. The cruise is a resupply run to Gough Island and Inaccessible Island, barely habited places (by humans at least, seabirds live there by the thousands!) in the middle of the South Atlantic Ocean. The ship is an icebreaker called Agulhas II, named after an important ocean current that runs along the coast of Southern Africa.
I've done this before. In March and April 2016, I lived and worked on the Australian research vessel Investigator running nutrient samples and deploying SOCCOM floats. You can read my blog post from that trip here.



Boxes of equipment left Scripps a few weeks ago, with the
floats themselves being shipping from Seattle.



So what does it take to prepare for a cruise like this?
Well, probably the most important thing is to get all the equipment I'll need to the ship with plenty of time to spare. This means that months in advance I get everything set up in the lab, make sure it works, test out all the spare parts (no Home Depot runs when you're at sea!), and then pack it up and send it on its way. Onboard, I will be analyzing the nutrient and dissolved oxygen concentrations of seawater from the surface to a depth of 2,000 meters (over a mile!). I will also be collecting samples that will be analyzed back in the United States for pH and alkalinity, as well as HPLC and POC, which are optical properties (more on all these in future posts!). So lots of equipment is needed! It was all picked up from my lab in La Jolla, California a few weeks ago and has landed in Cape Town. I arrive on Monday and the first item of business will be to make sure everything arrived intact.

I celebrated my October birthday last week by painting
happy little trees with friends. And yes, I'm bringing the
tiara to wear onboard on my actual birthday. 




On the personal side, there's a lot to do to prepare for being away from home for two months. Some fun things, like make sure to see all my friends before I go, take my dog for lots of trips to the beach, eat as many tacos as possible...I even celebrated my birthday five weeks early since I'll be onboard for the actual day. There are also some things that are less fun, like getting vaccines and anti-malaria pills from my doctor so I can explore Africa after the cruise, calling my bank to let them know not to shut off my cards when I try to use them from the other side of the world (almost literally, the antipode of San Diego is off the coast of South Africa. Find out yours here, it's fun!)

I leave tomorrow morning. It's a thirty hour travel "day" to get from San Diego to Cape Town, on top of the nine hour time difference. So leaving Friday morning has me arriving late Saturday night. I'll have Sunday to figured out when/where I am and hopefully see a bit of the gorgeous city. Then a few days setting up my lab on the ship, and off we go! I hope you'll follow along for more on this six week expedition to one of the most remote regions on the planet!

Saturday, January 14, 2017

Shout-Out to Our Classrooms!

One of the best parts about being out here is hearing from our shore-side partners!

And I do mean partners! Before setting out on this adventure, Climate Central teamed up with eight science teachers from six different schools...and most importantly, their students. Each of the science classrooms is using the SOCCOM floats to study earth science and how the climate is changing, and we couldn't be prouder of them!

But this relationship is symbiotic! They use our data, but they help us too! How? By adopting the floats! Through the "Adopt-A-Float" program, SOCCOM is allowing elementary, middle and high school students take ownership and participate in the science.

Now that we've deployed the last float, each of our floats has been named by the students, and each of them is successfully collecting data.

Here are the names the students chose and where their floats were deployed:

Float Number            Release   Deployment Location              School                           Float Name
SOCCOM01 12575  12/27/16  1255Z 057.338 S 068.293 W  Princeton Day School     RE Byrd
SOCCOM02 12573  12/28/16  0615Z 059.008 S 068.498 W  Princeton Day School     RF Scott
SOCCOM03 F0569  12/29/16  0348Z 061.991 S 068.818 W  Bear Tavern Elementary Titus
SOCCOM04 12545  12/29/16, 2150Z 064.189 S 069.101 W  Melvin H. Kreps M.S.      Southstar
SOCCOM05 12543  01/01/17  2145Z 066.383 S 074.468 W  Princeton University        Jorge
SOCCOM06 F0567  01/03/17  0056Z 067.258 S 084.231 W  Melvin H. Kreps M.S.      Kirby
SOCCOM07 12559  01/04/17  0738Z 068.289 S 095.441 W  Passaic Valley H.S          Darwin
SOCCOM08 12549  01/05/17  1941Z 069.666 S 109.093 W  Passaic Valley H.S.         Mann
SOCCOM09 12390  01/08/17  2043Z 068.249 S 128.484 W  John Witherspoon M.S.   Bell
SOCCOM10 12551  01/10/17  0522Z 070.651 S 136.483 W  Sandia Prep School         Sundevil Sam
SOCCOM11 12541  01/11/17  1016Z 072.346 S 146.343 W  Sandia Prep School         Sundevil Lion
SOCCOM12 12381  01/12/17  2243Z 075.644 S 156.968 W  Princeton Day School      EH Shackleton

John Witherspoon Middle School's "Bell" begins its journey
You can find all the data from the floats at http://www3.mbari.org/SOCCOM/AdoptAFloatviz.htm

It's exciting for the scientists on board the Palmer to find out the names the students choose and hear the questions they ask. Not only do the students get to participate in the deployment of the instruments, but now that the floats are returning data, these classrooms will be using the data directly from the floats (the same data that scientists use!) to understand the dynamics of pressure, pH, nutrients, and phytoplankton across the world's oceans.

Just being an observer on the Palmer has opened my eyes to a variety of new worlds - the macro-world of the Southern Ocean with penguins, seals, whales and icebergs as well as the micro-world of phytoplankton and nutrients that can travel across the world. This isn't my last post, but I hope through this journey so far, I've helped to open your eyes to these new worlds too, whether you're a student in the Adopt-A-Float program or you're a student of our world in any other sense!

Greta


Wednesday, January 11, 2017

Wait! First let’s talk about batteries and bladders!

I’ve gotten a few questions about how the floats work, and now’s as good a time as any to answer them!

How does the float control its depth in the water? 

Inside the float, near the base, there’s a bladder containing oil—mineral oil to be exact. The bladder has a pump that can either inflate the bladder or deflate it. Since we can’t change the mass, all we can do is change the volume. When the float needs to descend, the oil is compressed, using the pump. That increases the density, and the float sinks. When the float needs to rise, the pump releases pressure, and the density decreases, allowing the float to rise. This of course all means that the float itself has to have a very specific mass.

How long does the float “live”?

Technically, a SOCCOM float has enough battery life to take 268 profiles in the Southern Ocean. If we take a profile every 10 days. That gives us over over 7 years of data! Battery life isn’t the only thing that matters though. During the winters, the float is especially strained. Even with sea ice avoidance software, ice can still damage the float in stormy waters. The SOCCOM scientists will estimate the life of a float to be between 5 and 6 years—weathering 4 or 5 winters before it becomes unreliable or the battery runs out.

What happens when the float runs out of power?

When the battery dies, the float sinks sinks to the ocean floor, but sometimes, it can get washed ashore if it’s close enough to land. That’s why it’s got a sticker with contact information on it:



If someone finds a float, he or she can contact the scientists, and SOCCOM will retrieve and potentially be able to reuse the parts or learn more from the how it fared in the water. It would be great to be able to retrieve all the floats once they’re running low on battery, but ship time in the Southern Ocean is expensive and hard to come by. It’s far more cost-effective to use any and all ship time to deploy more floats, especially because the pollution caused by these floats is far and away less than any other data-collection method. Just think about a ship trying to collect all the profiles that a float collects! Just the fuel cost alone would be far dirtier than a float doing the job.

What uses the energy?

The lithium-metal battery inside the float powers three things: the bladder pump, the iridium satellite communications, and the sensors. About one half of the energy goes toward the pump; one quarter goes toward communication, and one quarter for the sensors.

P.S. We're about to deploy Sundevil Lion, named by Sandia Prep School in Albuquerque, NM!

Here's a photo of the float:


... and a photo of us together!



Thursday, January 5, 2017

How Do They Work?

By now, you know that these SOCCOM floats open incredible windows into a vitally important part of our climate system, the Southern Ocean, but how exactly do they do that?

Let’s take a look. First off, there are the sensors.

Here’s a photo of the top of one of the floats with the sensors labeled.

To start, take a look at the temperature and salinity sensor. That’s the black tower that has the tall holes in it. Salinity is measured by measuring the water’s conductivity. If the water has higher conductivity, that means there are more ions in the water, which means a higher salinity. If you know the temperature and pressure, you can calculate an exact number for the salinity of the water from this device.

The temperature probe is actually called a “thermistor” not a thermometer. The traditional mechanics of a thermometer use mercury, but a thermistor is actually a resistor (a metal, ceramic or polymer) whose resistance changes very precisely with temperature. Put thermo- and resistor together, and what do you get? Thermistor!

The reason why the pressure sensor is labeled differently is because you can’t actually see it! It’s behind all the other sensors, but it measures the pressure of the water around the float, and from that you can calculate the depth.

Because the float has these three sensors (T, S, and P), scientists will say that this float has a “CTD,” which stands for Conductivity, Temperature and Density, and that’ll get you your bread and butter parameters that you need to know about the water in every profile.

The pH sensor is connected to the temperature and salinity sensor by a tube that pumps water over from the temperature and salinity tower. That means the pH sensor is measuring exactly the same water that just had its temperature and salinity taken. This pH sensor is called an “FET,” which stands for Field-Effect Transistor. You might know that transistors can be used to precisely measure voltage, but what you might not know is that the voltage this sensor measures is directly proportional to the pH of the water! The tricky thing with this sensor is being able to package it in a way that we can get reliable data at different depths, temperatures and salinities. This particular sensor has just the right packaging to keep it going no matter what kind of punch Southern Ocean packs!

Next up is the oxygen sensor, over on the right. It’s an optical sensor, and it works by shining a blue LED into the water. The fluorescence properties of the water are determined by number of O2 molecules around. With no oxygen content, you’ll have maximum fluorescence, but any oxygen molecules in the water will quench a certain amount of the photoluminescence.

The oxygen sensor is kind of a variation on the nitrate sensor, which is short, and looks a little bit like a whistle. Instead of just blue light, the nitrate sensor sends many different frequencies of light into the water and measures the absorption spectrum of the water across the different frequencies.

Last but not least are the backscatter and chlorophyll sensors which we’ll talk about together because they’re wrapped up in one package down at the bottom of the float. (Why are they at the bottom? Because they’re heavy, and we want the float to stay vertical as it rises and sinks!)


Here’s a photo of Steve Riser with Southstar, named by Melvin H. Kreps Middle School. Down by his foot is the chlorophyll and backscatter sensor. The chlorophyll sensor optically measures something called chlorophyll fluorescence, which is slightly different from chlorophyll itself. When we deploy the floats, we calibrate that sensor using samples that we’ve collected from the larger rosette-shaped CTD.



Here’s a photo of that CTD. There are two parts to it—the 24 bottles around the edge, and the sensors at the bottom. This photo was taken right before it went out that door and sunk to a depth of 2000 meters. At different depths, the scientists will close the bottles, one at a time, in order to capture water from different depths, all the while monitoring the sensor readings from the ship.



The cable that holds the CTD from the boat is conductive, so as the rosette sinks, we can watch the data come in from the sensors, meter-by-meter. If there’s something particularly interesting at any depth, the scientists can actively “fire bottles,” or close them, capturing the water at that depth, on its ascent.

The CTD can also be sent all the way to the bottom of the ocean (which sits at around 4000 meters below the surface). Sometimes the scientists like to do “deep casts” like this. We’ve done that twice now, sending along some styrofoam cups. At 4000 meters, they’re under a heck of a lot of pressure. Oceanographers tend to measure pressure in decibars because it just so happens that the numerical value for pressure in decibels is close to the numerical value for depth in meters!

Take at look at this poor old Styrofoam cup!



Next up: we’ll take a look at exactly what these measurements tell us about the Southern Ocean!

Greta

Sunday, January 1, 2017

Ending 2016 at Rothera



As we approached, the British base, Rothera, we got our first taste of ice-breaking. It was thin sheet ice that stood between us and the Brits, the kind that took only a bit of pressure break. A long dark
crack shot down the ice in front of us. It widened quickly as we sailed forward.




The wind is fierce. I and a few of the scientists, including Stephen Riser, stood at the bow of the ship. Our hats, hoods, mittens, and heavy coats were doing their best to protect us from the chilling wind
that came straight to our faces and made our eyes tear up.

Every few minutes, we'd pass a pair of seals lying on the pancaked ice. They'd awaken from their peaceful nap in the summer sun, look up at us lazily and gave us a chiding roar. We couldn't really hear them over the sound of ice sloshing against our bow and the loud hum of the ship.



Rothera is the largest British Antarctic Survey base. There's an island just west of the Antarctic Peninsula mainland called Adelaide, and Rothera is located on the eastern coast of that island, so you can see the mainland from it. Once we docked, we stepped foot on solid ground for just a few hours. Each of us chose between taking a tour of the coastline around the base, the glacier, their marine aquarium, or their air facility. Ted and I opted for the glacier.



Up we went in the "Tucker-Terra," a monster Snow-Cat truck that conveyed us up the glacier to a snowy pass. The people working at Rothera take full advantage of their physical location. They're
rock-climbers, ice-climbers, skiiers, snow-campers, as well as scientists... and runners.

December 31st was the day of their annual 10k race. It took place on the runway at the base. The Rothera-rians invited the Palmer-ians to join in the race, and we gladly accepted!

Some of us even pulled together a 5-person relay team, (snagging first place in our division... by default).

In the summertime at Rothera, (which is right now), the sun never really sets. It might resemble dusk around midnight, but that's it. At 0300, it may as well be 0800. And it's bright... the ice and snow
reflect so much light. That makes it easy to spot the tiny dots that are actually penguins!


After our visit to Rothera, we returned to the ship and began sailing back out into the deep ocean. Our next float will go into the water later tonight. I'll keep you in suspense of the name...

I'll be back with a summary of how it goes and a walk-through of a typical float profile!

Greta