NAAMES (North Atlantic Aerosols and Marine Ecosystems Study): NAAMES-II Expedition: May 16, 2016May 16th, 2016 by Kristina Mojica
As we progress on our journey north, it is as if we are travelling back in time through winter and on towards the Arctic. When we left Woods Hole, we were treated with blue skies, calm (occasionally glassy) seas, and reasonably warm air temperatures; a complete contrast to the November cruise! We have been extremely fortunate with the seas thus far and many of us have weaned ourselves off our seasickness medications. With it being late spring, the daylight hours are long and we have been treated to some spectacular sunsets (and if you’re keen for a 3:30 am start, the sunrises aren’t too shabby either)! The sea life has been more abundant than on the previous cruise with a number of whale and dolphin sightings.
But that was all about to change as we entered the ‘ice field’ off the coast of Newfoundland early yesterday morning. Some of us were up at dawn (3 am!) to catch our first glimpse of ice, but alas, we were shrouded in a thick blanket of fog and could barely see 50 m from the boat. It was absolutely freezing and there was certainly an eerie feel; it seemed like we could have been surrounded by icebergs and have no idea about it. But by that point I wasn’t quite sure I even wanted to see an iceberg because if we did, we’d almost certainly be on top of it the fog was that thick (the ship’s foghorn was put to good use)… As the sun rose above the horizon, the fog began to disperse and the sky burned orange. It was pretty special, despite the lack of icebergs. Regardless, excitement bounced around the ship all morning; even some of the crew had donned their cameras in anticipation of the ‘ice’ we were about to see. The fog came and went again and the seas started gathering a bit more momentum. Both the air temperature and the seawater temperature plummeted below 0 °C and the waves began dancing in every direction. But alas, luck was not on our side and the icebergs remained elusive. The crew decided on the ‘path of least resistance’ approach (realistically, the safest option) and managed to clear the ice field by late afternoon. So, no icebergs, but we did get a taste of the Arctic temperatures and colder, rougher weather that is likely to stick with us for a few more days.
This evening, we will arrive at Station 0; our first practice station! We will be getting up at midnight to begin overboard sampling and have a ‘wet’ run-through of most of the deployments we will be making at the real stations. I will be collecting water samples from the CTD rosette casts to look at the cycling of small volatile organic compounds by the plankton in the surface ocean (such as the dimethyl sulfide you’ve heard about in previous posts, which can be released into the atmosphere and lead to the formation of aerosols). We think that in surface ocean, the phytoplankton (the tiny ‘plants’ of the ocean) are producing these volatile carbon compounds, just like trees do on land. Have you ever noticed the smell of a pine tree? That comes from volatile compounds released by the pine tree! The phytoplankton do the same, especially when they get stressed out or die and begin to sink down through the water column. That leaves room for the bacteria to come along and feed on all the carbon compounds left by the phytoplankton (just the same as you eat all your vegetables, just like your mother told you…). Any volatile compounds that are not consumed by the bacteria can then get released into the atmosphere, where they have a number of important roles controlling our climate.
The water samples I collect are incubated in polycarbonate chambers that are bubbled with synthetic air; we use synthetic air because it is cleaner than the regular air we breathe in and so we can be sure that anything we measure comes from the seawater (and not the air). Our chambers are kept at seawater temperature and we have blue and white LED lights that we use to simulate the light conditions the plankton might experience in the surface ocean. Compounds that are produced by the plankton will be stripped from the seawater by the bubbling air and we can then measure them with our specialized mass spectrometer, the aptly named ‘James’ – because he is #007 of his kind! James has been kept very busy on the cruise so far, running almost 24/7, because we have been able to collect seawater from the clean flow-through line running through the ship (which pumps surface seawater through from the front of the ship). So we are excited to see what we find! Wish us luck for Station 0 tonight!