Date: Thrs, 08 Jul 1999
Subject: Rough waters and science: phytoplankton and modeling/ctd groups Pictures: Phytoplankton Team, Modeling/CTD Team

We are running in front of a big storm, hoping we can get to the shelter of the coast before it catches up with us. A few moments ago, I went up to the bridge to take a look outside, and it was impressive: dark waters churning all around us, with big white crests on them. And when you looked toward the back of the ship, you could see the water rising way above the level of the deck, looking like it was intent on covering it with water momentarily.

Inside the ship itself, though we can of course feel the swell, it is not as bad as one would expect from the scene outside: the ship has a system of water stabilizers which do quite a good job at preventing it from rolling from side to side. But still, maneuvering through hallways and up or down stairs becomes an exercise in balance control (not to mention trying to get dressed other than sitting down, or taking a shower...

For those of you who saw the web page sent a couple of days ago, if I tell you that we just left station 600.160 and are heading toward 600.140, where we should be in about 2 hours, you should be able to 1. locate us on the grid...2. Figure out the speed of the ship and...3. figure out latitude and longitude: anyone wants an A???

Despite the unfriendly elements, work continues, and so far we have been able to lower the CTD, as well as nets and the PRR into the water at each planned station. However, yesterday the swell got to me. I forgot that I should not try to read, especially small print, when there is so much motion (same as I cannot read in a car): I started feeling queasy, so I had to forget about web page and other work, and go lay down for a while... when I woke up it was the end of the afternoon! Today seems much better, either because my body is getting used to the storm, or thanks to the patch I put behind my ear.

Today, I sat down with Doug and Maria to ask them about their work. Let me tell you, squeezing five minutes out of these PI's is sometimes difficult: they seem to be busy every minute of the day!

Maria and her group (left to right: Maria, Marnie, Martha, Irene, David and Brian) study phytoplankton. That is a very long name for microscopic, unicellular plants which float within the water. Phytoplankton, making use of the sun's radiant energy and in the presence of nutrients produce organic carbon. They are very important since they represent the base of the food chain: they get eaten by krill, krill larvae, protozoa and salps, which themselves are a source of food for birds, penguins, seals, whales, etc...

Maria and her group are also interested in the location of the phytoplankton, their distribution, composition and quantity,and the difference between summer and winter stages (because of greatly reduced sunlight, an essential element for growth, phytoplankton grow very slowly or not at all until light returns in the spring and summer.

They not only sample the water, but also the different kinds of ice, to see if they contain ice algae. A lot of the work they accomplish is done looking through a microscope, where they study the different species of phytoplankton by their morphology, fluorescence, and the presence of chlorophyll_a (only live cells contain it).

I mentioned, in an earlier web page, that this group also works in two trailers, set up on the helo deck. The reason for this "quarantine" is that they work with C14, a radio-active material. By "spiking" a sample with C14, then placing it under conditions where growth is possible, the uptake of C14 can be used as an indicator of how much organic carbon is produced (i.e., how much growth has occurred) by the phytoplankton. Analysis of the concentrations of photosynthetic pigments (compounds that absorb light) provides an indicator of various phytoplankton groups, since various phytoplankton groups typically have different pigment composition.

I also cornered Doug after he had just finished getting the CTD ready for the next cast, which means making sure that all the bottles are empty, open and triggered so they can be remotely closed at the right depth.

Doug (and his team mate Rich) are concerned with making measurements of the physical characteristics of the ocean, primarily the temperature and salinity as a function of depth but also other properties as well: ie oxygen, fluorescence, light absorption and scattering. Attached to the CTD are a number of sensors which can detect these properties as the CTD goes up and down through the water column. Selected properties can, in real time, be plotted on a computer screen in front of Doug, and sometimes he gets really excited by what he sees there: scientists get excited, I've discovered, at the strangest things!

Like with most of the research done on the ship, this method of doing physical oceanography is relatively new, and really took off with the birth of computers, These physical data as well as many of the results obtained by various groups will become part of a base line of data upon which other scientists can build: that is the concept of an LTER.

The measurements which Doug and Rich record provide background information on the ocean, and by observing changes in salinity and temperature, they can find out where the water comes from (there is a concept of a "great conveyor belt" of deep sea currents, which circulate at all times around the world's oceans), and its "age". I enquired what "age" meant in terms of water, and was told that it means the amount of time that a given body of water has been submerged without going back to the surface to replenish itself by exchanges of heat, O2 and CO2 with the atmosphere.

Another element of study is how the physical characteristics of the ocean affect the formation of sea ice and the exchange of heat, wind energy and gases between water and air. Sea ice is an important barrier between the ocean and atmopshere, thus its presence or absence makes a very big difference in ocean/atmospheric interaction. Consequently, sea ice is an important, if currently poorly understood, influence of global climate. One objective of this work is to better understand this influence of sea ice and to be able to differentiate between annual variations and longer term trends.

I asked Doug if there had been any surprises for him on this cruise, and he answered that he had been surprised by how little ice seemed to have formed this winter, but also by the fact that sea ice seemed to be able to form even when water is above freezing point.

While I have been providing very brief descriptions of the diffenent groups it is important to understand that these scientists are working as an integrated team: the physics, sea ice, optics, chemistry and biology are not, to nature, divided into distinct disciplines. Thus, this interdisciplinary team is also working to interact across the traditional boundaries of science so as to better understand the broader elements of this polar marine ecosystem.