Word Art

This is a cool visual of the word frequency of my latest research. It's about iron (Fe), light, and phytoplankton! I made this with the wordle app (www.wordle.net).

Surprising results!

The Antarctic keeps surprising me! When we studied the phytoplankton in the Amundsen Sea Polynya in Antarctica in 2009, we discovered that melting glaciers release iron in the water and that phytoplankton can use that iron for growth and photosynthesis. So, melting glaciers support phytoplankton growth, and because phytoplankton take up CO₂ from the atmosphere this slows down global warming a teeny tiny little bit.

So when we returned to the Amundsen Sea in 2010 to further explore the properties of phytoplankton there, we did not expect to find any effects of iron in the water on phytoplankton. However, we were wrong! We confirmed that glaciers release iron in the water. And we confirmed that phytoplankton can use that. But if you give the phytoplankton even more iron, they grow even faster! Especially, the phytoplankton that was growing at distances of more than 30 miles from the glacier could use more iron. It is like growing tomatoes in your yard, they may grow rapidly and look great, but if you add extra fertilizer (nutrients) they might grow even bigger.

This was quite a surprise to us. Melting glaciers release iron in the Amundsen Sea, and the Amundsen Sea has the most phytoplankton growth in the whole Antarctica, how can iron availability still limit the phytoplankton? One of the clues is that iron is very insoluble in water that contains oxygen. Almost all iron will precipitate and sink out of surface waters, before phytoplankton can use it. So no matter how much iron is released by melting glaciers, most of it will likely not be used by phytoplankton. And, thus, the effects of melting glaciers on phytoplankton will likely be local and not expand very far into the Southern Ocean. Nevertheless, when glacier melting rates increase it is likely that some more iron will be used by phytoplankton, which means a little bit more phytoplankton growth to stop climate change.  However, while phytoplankton growth in Antarctica supports the entire Antarctic food web and is thus generally a good thing, too much phytoplankton growth may be harmful with unknown consequences. Meanwhile, we will keep studying to find more pieces of climate change effects in Antarctica.

http://elementascience.org/article/info:doi/10.12952/journal.elementa.000043

Last station

At 2:45pm we sampled our last station of the cruise! The captain set the time for departure based on his estimate on the transit time back to Punta Arenas. This depends on the location of our last sampling, the latest satellite images with the sea ice conditions, and the weather forecast for the Drake Passage (right now it looks neither particularly good, nor bad). The time kept creeping forward, so Kevin had to cram in as many of the last minute sampling as possible and almost everyone is happy. The last sampling of sediments didn’t make it before the departure which resulted in one unhappy scientist. But 19 other scientist are happy and relieved everything went really well and they can take a breather. We got some pretty interesting results of this area that is well studied in the Antarctic summer, but not this early during the season.

This cruise has gone so fast, it is unbelievable it is almost over. This was the shortest cruise I have ever been on and it was surprisingly stressful to not have much time for layover days in case stuff didn’t work (which always happens in Antarctica). But thanks to the hard work of everyone on the ship we did almost everything we planned. Everyone was amazing and we worked together really well.

This is also a little bit of time of reflection on what an amazing place Antarctica is to come to and study how the ecosystem works. Also, the NB Palmer is a special ship that I have now spent almost 200 days on over four different trips. This ship and the people have a very special place in my life and I hope very much to come back. Because you never know how the future will look and what proposals will get funded every trip may be the last one, so time to soak in some more sea ice images and hopefully a few more penguin sightings. But first some sleep!

Our cruise track 3 days ago. We ended up finishing the red rectangle, so we now have 3 ½ transects from the ocean towards the western Antarctic Peninsula.

Phytoplankton

We are here to study Antarctic phytoplankton. Phytoplankton are microscopic little plants (OK, officially they are protists) that grow in the water everywhere. They are the basis of all life in the oceans, so kinda important. They need light for photosynthesis and nutrients for growth. In the Antarctic waters iron is often the limiting nutrient for phytoplankton growth. Iron is very insoluble in water and there are few sources of iron in Antarctica. Even though phytoplankton only need a little bit of iron, there is still often not enough available for optimal growth. One of our research questions is to determine if the phytoplankton are limited by the availability of iron or light and how different phytoplankton species respond to different availability of these two factors.

We are now sampling Antarctic waters in the spring, earlier in the season than I have ever been here. During the winter, there is no light, so phytoplankton cannot grow. When the spring begins the days get longer very rapidly and the light availability increases, so phytoplankton can start to grow. We always thought that around this time light availability controls the phytoplankton growth.  We reasoned that there is still plenty iron available for the phytoplankton, as they have not had the time to take it up yet. However, we now measure very low concentrations of iron in the water, so we may have to rethink that. It may be that the phytoplankton are constantly starved for iron, throughout the whole growing season. Another factor is that large areas are still covered by sea ice that prevents a lot of light from penetrating the water, so here the phytoplankton are still in the dark. Moreover, phytoplankton also grow in the ice. They are then called “ice algae” and they grow at the bottom of the ice, where there is a bit of light available. We have no idea how much iron is available to these algae, but we’re trying to measure it (the methods to measure iron in sea ice are not well developed, so we’re giving it a try).  Some ice algae are different species from the ones we find in the water column, and some are the same. We are now finding a lot of a species that we normally find in the water column in the ice, which is very cool. It raises all kinds of questions on how a unicellular species goes from growing in the ice to growing in the water column and vice versa.

One of the coolest pieces of equipment on the ship takes pictures through microscope lenses of all the phytoplankton in samples that we take from the ice and the water column. So we get a lot of very pretty pictures and a good sense of what is growing in the ice and in the waters below it. 

Eucampia

Phaeocystis

Chaetoceros

Diatom

Radiolarian

A day in the life of an Antarctic oceanographer…

5:26 my alarm goes off and I wake up to the sound of sea ice crushing under the ship. Through my little porthole I see a beautiful morning in the white world of sea ice. I’m lucky enough to have my own cabin this cruise, so I turn on the TV system that displays the waypoints and all kind of other information to see what’s going on. We are still 10 nm away from the next station and we’re going slowly through the ice. At 6 am, I relieve Kate from her watch and she tells me what has happened during the night. By now everyone is pretty much in the groove and everything went well. It looks like it will be a while before we are at the next station, so we have some time. It is a beautiful morning and Gert is going outside to take some pictures. It is tempting, but I decide to catch up on a little bit of sleep and go back to bed for a nap.

8:15 Pring!!!!  Gert gives me a call to let me know that the “CTD is in the water!” The CTD (conductivity, temperature, density sensors) is our main sampling device. The sensors display the data in real time on the computer of the CTD station. This is where everyone hangs out to see what’s going on under the ice. The CTD detects some fluorescence of phytoplankton pigments down to 70 m depth. We measure the water column properties all the way to the bottom, which is about 500 m deep here. On the way up, we close big 12 Liter (3 gallon) niskin bottles with a remotely controlled trigger mechanism to take samples of the water column. When the CTD is on deck, everyone crowds around it to take their measurements. For some people this is done within minutes, other will take up to three hours.  A student will do my measurements, because I will be on deck for the next three hours to help with other sampling.

9:00-12:00 Together with two technicians and another scientist we are working on the back deck to get water that is not contaminated with iron or other metals to the trace metal clean van where Rob is ready to filter it and measure the very low concentrations of metals in the sea water (I’ll explain more later).

12:00 Time to warm up and have lunch in the galley

12:30 Coffee time in the aft control room. The controls of a lot of the winches are here and it’s a nice place to look out over the back deck and the ice. We make a cup of cappuccino with the espresso machine in the office of one of the techs and hang out for a bit.

13:00-15:00 Bottle washing with Tom! We do experiments on board with phytoplankton without contamination from the trace metals from the ship. So Tom and I dress ourselves in stupid white clean room suits and get in the trace metal clean van to wash our experiment bottles with acid and ultra clean water. I label 63 bottles to be ready to start an experiment tomorrow. We will fill them with water & phytoplankton and add iron to half of them in order to study the effects of extra iron on phytoplankton growth at different light levels. The bottles will then be incubated in incubators on deck so the phytoplankton can grow.

15:00 A cup of tea on the bow! The ice has increased and we’re going pretty slow now. Outside, on the bow it is amazing to see how the Palmer crushes through the sea ice. At one point we come to a full stop. After a while we hear some additional sound from the engines and with four engines we come roaring back to speed.

15:30 Time for some data analysis on the computer. It is hard to find time and stay up with all the data we’re collecting. Meanwhile, our progress through the ice is slowing down and Kevin (our professor and chief scientist) and I discuss abandoning our sampling line and turning around. This means the experiment that was planned for tomorrow will have to start tonight, together with a lot of other measurements. We make a schedule for the night so that we have enough hands for all measurements and experiments and everybody will get at least a few hours sleep.

18:00 The cooks Mike and Michael (both from New Orleans) have prepared a delicious dinner in the galley.

19:00 I’m anxious to see the CTD go in the water, because I will have to get up at midnight to start the experiment. Time to label some last vials for the experiment and play on my ukulele while waiting. When the ships officers manage to make a hole in the ice that is large enough to sample, we see on the CTD sensors that there is no phytoplankton whatsoever in the water. This area has been covered with ice since the winter and no light has penetrated yet to make the phytoplankton grow. We decide not to start an experiment, which means the schedule for the night is rewritten and I don’t have to get up at midnight J. 

20:00 I help out with the trace metal clean sampling on the back deck and 2 seals come to check us out and use the hole we made in the ice to breathe. It is a very cool show!

21:00 Everything goes smoothly on deck and I’m not needed anymore. Time for a shower and to go up to the bridge to enjoy the beautiful icescape and hang out with the chief mate Chris. Officers are always happy for the scientists to come up and hang out and chat a bit. The officers are mainly the same from last year and we got along really well, so it is fun to catch up and gossip a bit. It’s a beautiful night, with the mountains of Adelaide Island on the horizon at ~60 nm away. Two emperor penguins swim around in our sampling hole, it doesn’t get much better in Antarctica than this!

00:30 A night time abandon ship drill. Every week there is an abandon ship drill for all scientists and crew and the coast guard requires a quarterly drill at night. This seems fairly useless as it is still light at midnight, but who am I to think about these things!

1:00 Time to go to bed. The sampling continues to 4 am, after which we turn around and head a bit further north for more sampling. This transit means I get to sleep in, yay!

Sunset two days ago.

More scenic sampling!

Hi all,

Things are busy on the Nathaniel B. Palmer! We are sampling the phytoplankton in the ice and the water column to quantify and characterize them (we kill them and take them home to analyze!). Several people are doing different experiments with the phytoplankton (we torture them with different environmental stresses and then we kill them!). Things are going pretty well and it is very scenic! Last night we came very close to a big iceberg with some very cool layered ice structures. Today, several Minky whales were checking out our sampling devices and used the hole the Palmer made in the sea ice to breathe. It was magical to deploy our gear while you hear the puffs of exhaling whales at 50 ft from the ship. You wonder what they make of our big orange ship with equipment dangling over the side in their white and grey world.

Scenic sampling!

Today we sampled the waters close to the western Antarctic Peninsula. We did not find much phytoplankton, but it sure was pretty! And we saw a school of penguins porpoising around, my first of this cruise.

Later in the evening some lucky researchers took the zodiac out to get some samples of sea ice, sea ice algae, and krill that is eating the sea ice algae. This was one of the most beautiful days I have ever experienced in Antarctica! We are so lucky to be able to work in this amazing place! Right now, the moon is shining over the pancake ice that moves in a huge swell that comes all the way from the Drake Passage to here. It is almost too beautiful to go to sleep, but in seven hours my alarm will sound for some more sampling. Probably not as scenic as today, but we’ll take it anyway!