King Neptune and the end of science

The polar circle is located at a latitude of 66° 33′ 44″ S. South of this latitude there is 24 hours of daylight in the summer and 24 hours of dark in the winter (for at least 1 day a year). During our cruise we crossed this line, but since summer is just starting we did not get 24 hours of daylight, but as you could see in the previous blog, it was pretty close.

The polar circle might be defined based on daylight, but it also has a somewhat more mythical meaning. South of this latitude, one enters the realm of King Neptune. Rumour has it that he is not always pleased with intruders into his kingdom and that the consequences for those involved could be severe…… The latter information was given to those on the ship who hadn’t been this far south before (known as pollywogs) and this was the first step in the ancient maritime tradition of a crossing ceremony. Due to the unpredictable nature of work at sea, the arrival of King Neptune on board was delayed several times, but finally, when we were already on our way back, he made his appearance with his wife, their baby and his royal guard.

Ella was one of the unfortunate souls who needed to please King Neptune and undergo a special cleansing ritual. Rob is no stranger to this ritual as he crossed both the Arctic and the Antarctic Polar circles as well as the equator so already got acquainted with the King on those occasions. 

Luckily Ella did a good job of impressing the royal family with a skid featuring some crewmembers, a mermaid and a trace metal chemist who had to figure out a way to get trace metal clean samples after the trace metal clean rosette was no longer an option. All that was needed after this was a short visit to the barber/beautician/tattoo artist to become presentable and picking up a toy for the baby from a sea chest.

Ella getting a makeover with some unusual beauty products (left) and trying to get the baby a toy to play with (right)

Overjoyed that she had managed to pass the ritual and now had entered into King Neptune’s inner circle, all that Ella needed now, was to have her picture taken as proof of this joyful moment.

Besides rinsing of some excess beauty products of course……

The crossing ceremony also marked the end of all science on the ship. We are on our way back and done with analysing samples aboard the ship. Now it is just a case of packing everything up, cleaning the labs and doing the unavoidable paperwork to get our precious samples back to the lab at Otago. So for now it is goodbye ice, goodbye penguins and whales, but also goodbye to all the people aboard the ship. One thing about working so closely together with a group of people on the same project is that you get to know them well in a quite short time frame. The saying goodbye to our shipmates is never easy, but we might sail together again in the future as there is much, much, more science to be done here around this marvellous white continent. 

Thanks to all crew and scientists aboard the Palmer for your help and making this expedition unforgettable!

Life on board the Nathaniel B. Palmer

Life on board the Nathaniel B. Palmer

We have been living on board for about three weeks now and the ship almost feels like home. Work continues around the clock so there are always people working. There are hot meals four times a day and coffee and snacks are available all the time. To make sure we do not go overboard on the food and snacks, one of the scientist organised weekly Monday weigh-ins, just in time to see if you have to hold back on Taco Tuesday.

Ella and Rob divided the day in two blocks where Ella is working the night shifts and Rob the day. However, now that we are sampling with two GO-FLO’s on a wire, it takes a long time to collect samples. At many sampling locations (called stations) we want to collect a large number of samples and we both need to be present. This means sleep is not always easy to come by, but who needs sleep when there are metals to analyse and beautiful views to see. 

A sunset/sunrise over the ice. We are below the polar circle and as the summer is starting down here, it barely gets dark. The sun starts to set but rises just as it disappears below the horizon. In a few weeks there will be 24 hours of daylight around here. If you look carefully at the left photo you can see the ice is not a solid sheet anymore, but consists of many small pieces, called floes.

 

 

Rob’s cabin after a bit of a tidy up (guess what is behind the curtain…..)

On board, we sleep in cabins that most of us have to share with a roommate. The cabins have bunk beds with curtains that come in handy if you want to sleep during the day and do not want to be disturbed by your cabin mate who is on an opposite shift. Climbing in and out of the top one can be a challenge when the ship is rocking and rolling on the open ocean! Lately we have mainly been in the sea ice that, at this time of year, still surrounds Antarctica. So no more rolling, but if the ship is breaking through some heavy ice, it can still be quite bumpy. Every spring this ice breaks up and sunlight penetrates the water, allowing phytoplankton to flourish. The phytoplankton is the food for bigger organisms that feed the iconic Antarctic wildlife. It is still early in the season, but we have spotted some seals and whales and an Emperor Penguin paid the ship a visit! It stayed next to the ship for a long time while we were taking samples, posing for pictures and squawking at us, almost as if it was asking us what we were doing and why we looked so funny.

 

An Emperor Penguin and a whale. The greenish discoloration you can see in the ice behind the whale is actually phytoplankton that lives in the sea ice. These are known as ice algae.

In this photo you can see the ice algae even better

Beautiful view of the Antarctic Peninsula with the sunlight reflecting off a glacier.

Bad Luck

Bad luck

After about 17 successful deployments of our trace metal clean rosette, we were faced with a little tragedy. The trace metal rosette broke and we can no longer use it to collect our samples. This does not only affect us for the iron measurements, but other scientists on board were also relying on trace metal clean water for the work they are doing. So we had to explore alternative methods to collect water without contaminating it for iron and other metals.

We tried collecting water with the zodiac. We would lie flat on our stomach on the tip of the rubber boat while it was slowly going against the wind and current and dipping a clean bottle just below the surface. This way you can collect water that has not been contaminated by the boat. This worked relatively well, but it is quite time consuming and you can only get a surface sample and nothing from deeper in the ocean. Also when there is wind and a lot of waves it becomes quite tricky to not lose the sampling bottle or yourself for that matter. During the last zodiac sampling exercise when the sea was quite choppy, Rob was held by two guys while sampling from the tip of the zodiac and got very refreshed by waves splashing seawater of about -1.7°C (salt seawater freezes below about -1.8°C) in his face.

Sampling from the little zodiac in the open ocean. On this day the water was quite calm but the zodiac looks awfully small on the big ocean

Rob going to get some trace metal clean samples from the zodiac

In the mean time we had been pondering about a way to get more samples, also from deeper in the ocean. We still had two spare GO-FLO’s left and with the help of Tom, a marine technician on board the ship, Rob managed to rig the GO-FLO’s so that they could be attached to the cable by themselves and be closed by dropping a ‘messenger’. A messenger is a weight that wraps around the cable that you can then drop into the water. It sinks quite fast along the cable until it meets the first GO-FLO that is attached to the wire. The messenger then hits a bar that is subsequently pushed down and the GO-FLO closes and releases a second messenger to close the second GO-FLO that is attached to the wire below.

Left: Getting the GO-FLO’s on and off the wire takes a couple more hands, luckily everyone is helping out. Marine Technician Alec and scientist Anna are very happy they managed to get the GO-FLO attached. Right: Taking the GO-FLO back of after deployment, you can see the messenger weight on top of the white push bar that Tom made from scratch.

This was how trace metal clean sampling with GO-FLO’s was originally done before trace metal clean rosettes existed, but the GO-FLO’s we had were modified to fit on the trace metal clean rosette and did not have the necessary parts to be deployed on the wire. Luckily Rob knew how this was supposed to work and Tom is a very skilled craftsman who was able to make the missing parts. It took a bit of tinkering and improvements as we were going, but we now have two working GO-FLO’s that we can deploy on the cable. Based on the length of cable used, we know how deep we sample and we have successfully sampled to 750 m depth. It takes the messenger about three minutes to reach this depth, but overall the whole process is very time consuming. To get samples at six depths, we have to deploy three times and in between have to wait for the samples to be drawn from the GO-FLO’s , taking about three hours. With the trace metal clean rosette it would take only an hour and we would have twice the amount of samples! But at least we are still able to continue our work in this spectacular place on earth where Rob finally managed to photograph a lonely penguin.

A lonely and distant penguin, but a penguin nonetheless!

Small icebergs on the horizon.

Big tabular iceberg in the sea ice

Measuring Iron

After a crossing the stormy Drake Passage and feeling a bit seasick, we have are now near Antarctica where the sea has been much quieter and filled with ice. You can see where the ship is on this website: http://www.sailwx.info/shiptrack/shipposition.phtml?call=WBP3210

 

 

The shore of the Antarctic Peninsula  with small icebergs floating around                      The view from the snow covered back deck

There have been plenty of seabirds such as albatrosses and penguins, but we have not yet spotted a penguin. Other people on the ship have, so will keep an eye out for them! This is not so easy though when you spend most time inside our bubble where the iron measurements system is now working around the clock.

Here you can see our Flow Injection Analysis set up that we use to measure the concentration of iron. On the left, inside the flow bench, is the autosampler with small bottles full of different seawater samples. It gets pumped around into the network of small white tubes you see in the middle. Here the iron in the seawater catalyses the reaction between luminol and peroxide. This reaction produces blue light that we can measure, more light means more iron. The lowest concentration we have measured so far is 0.03 nanomol per litre of seawater (0.03 x 10^-9).

Before we can measure a seawater sample, we have to collect it from the ocean. We use a trace metal clean rosette that can collect water at 12 different depths in the ocean. In the next photo you can see the rosette on deck, just before it gets deployed and in the ocean on its way down to the deep. The grey tubes are called GO-FLO samplers. They are almost completely made out of plastic and do not contaminate the seawater with metals. The GO-FLO samplers are open on the way down and when the deepest point has been reached, one can close the samplers on the way back via a computer on the ship. This way we get 12 samples from 12 different depths.

The trace metal clean rosette on deck (left) and in the water (right). The rosette is suspended on a kevlar cable that is also free of metal. On the inside of this cable is the communication wire that allows closing of the GO-FLO’s as well as the reading of the sensors that are attached to the rosette.

After the rosette comes back on deck, the GO-FLO samplers are taken of the rosette and carried to the trace metal van. This is a modified shipping container, that just like the bubble, has clean air inside that is free of dust and metals. To keep it this way we dress up in very fashionable looking suits as you can see in the next photos.

Rob inside the trace metal van wearing a trace metal clean suit. All 12 GO-FLO’s are hanging on the wall and are ready to have water drawn out of them for iron analysis on board the ship. In addition we take samples to take back to the University of Otago to analyse them for other metals such as manganese and zinc.

Inside the trace metal van it is very easy to forget were you are, but when you come out, you might all of a sudden be greeted by an amazing vista of melting Antarctic sea ice! In the next blog we will write about life on board the ship.

Leaving for Antarctic

We arrived in Punta Arenas in Chile on the 22^nd of October after leaving Dunedin. Since we crossed the International Date Line, we arrived about the same date and time we left which felt slightly strange. Our home for the next month, the US Research Vessel Nathaniel B Palmer was already waiting for us at the pier. 

This large ice breaker will take us to the Western Antarctic Peninsula where we will take samples to measure the concentration of iron and many other metals. The concentrations of metals are incredibly low, comparable to 1 paper clip dissolved in 15 Olympic swimming pools. This means you have to be extremely careful to not contaminate the samples, which is not easy on a metal ship. Additionally, there is plenty iron in the human body, including in skin particles or hairs. 

To keep our samples clean, we had to build our own clean air laboratory on board, called a ‘bubble’. This is made from PVC tubes, plastic and lots of tape. Filtered air that contains no dust or other particles is blown into this, making the plastic walls bulge out which made people call it the bubble. Inside we have ‘flow benches’ that blow clean air in and keep all contamination out of our samples. 

 
Building the bubble with PVC tubes, plastic sheets and lots of tape! On the right you can see the filter through which the clean air is blown in and on the bottom left one of the flow benches.

In the next blog we will show some pictures of how we dress up in suits inside the bubble and of the (hopefully by then) working set up for the iron measurements.  

Introduction to the project.

Introducing Rob and Ella, lecturer and Honours student from the University of Otago’s Chemistry department. We will be investigating the amount of dissolved iron in the oceans and seas around Antarctica. On this blog we will share some photo’s and experiences.

Dr Rob Middag (left) and Ella Patterson from the University of Otago

Why dissolved iron?

Metals are not usually regarded as food, yet metals are essential nutrients for all organisms. They form the reactive centres of enzymes, enabling these to perform biochemical functions, such as oxygen-transport or photosynthesis. As such, trace metals are central to the health of individual organisms as well as entire ecosystems. In the open ocean, the base of the food web is formed by unicellular algae, known as phytoplankton. For certain ocean regions such as around Antarctica, it is known that trace metals, notably iron, can limit the amount of phytoplankton that can grow, and thus the amount of life that can be sustained. Since phytoplankton take up CO₂ from the atmosphere, iron influences atmospheric CO₂ levels and global climate. Coastal Antarctica harbours large phytoplankton blooms that sustain Antarctica's key higher organisms such as penguins and whales. This region is experiencing dramatic change as the glaciers are melting rapidly. This project will reveal what role trace metals play in the Antarctic ecosystem and give us the ability to predict how its role in global climate will change under future climate scenarios.