LTER Palmer Education: Field Projects

Date: Mon, 5 Jul 1999 21:47:14 +0100
Subject: Open water to the north, science overview and Krill Team
Pictures: Net Mocness, Netted Krill, Ice with NBP, CTD, Krill Team,

How easy it is to forget, after days walking on the ice, that the ocean is really a body of moving water!!! I guess it decided to remind all of us of that fact, and as we proceed back toward the north, we have been encountering swells which remind us of our first days of the cruise. There has been a low pressure system over the Drake, which is responsible for this, and we have taken to tying things down again. Nothing drastic yet, but I'll sure be glad if this changes before we start the actual Drake crossing (not until the 14th of July).

The swell, however, did not prevent us from celebrating the 4th of July in true fashion: yesterday at 4pm, there was a real barbecue going on the helo deck, with chicken, hot dogs and hamburgers, and in the hangar, a table loaded with food, including a cake decorated as an American flag.

After eating, there was music and dancing (not easy with the swell, it's amazing how it affects your balance!), babyfoot games and..fireworks! These were red flares with parachutes, fired from the deck, which illuminated the ice as they came down. There was something surrealistic about the whole event and I had a fleeting thought that I had been given a part in a Fellini movie!

But, despite the celebrations, work goes on! I thought I would take advantage of these next few web pages to try and explain in terms understandable to non-scientific minds what has been going on here for the past few weeks. My criteria for an "understandable" explanation, as I interview the different PI's (principal investigators, or group leaders) are simple: if I can get it, so can the rest of the world! If not, simplify, please! And watch your language (unknown technical terms not allowed)...

Let me start by stating, in words stolen from Ray, the purpose of the cruise: "...an LTER (long term ecological research) sea ice process cruise to investigate and understand sea ice growth processes and the relationship of this processes to the biota (biological processes) during this sea ice growth period.

Key goals of the cruise are to:

  • 1) investigate processes associated with frazil and pancake ice formation.
  • 2) study linkages between the various stages of sea ice growth and the associated biological (ice algae, bacteria, krill) and chemical (pigments and nutrients) constituents.
  • 3) determine the winter association (abundance and distribution) of Adelie penguins in association with the ice edge."

    Now, if you are like me, you read this and say: "Fine! But why is this important? Why are we spending all this effort (not to mention money) to see how ice forms?"

    This is what Ray explained in response:

    The Antarctic marine ecosystem - that assemblage of plants, animals, ocean & sea ice in the Southern Ocean - is the focus of study for the Palmer LTER. This ecosystem is among the largest ecosystems on earth and is estimated to comprise an area of about 36 million square kilometers. A dominant and distinguishing characteristic of the ecosystem is sea ice, which ranges from a minimum extent of 4 million km2 in February to a maximum extent of about 20 million km2 in September. Thus the seasonal growth and decay of sea ice defines a sea ice zone of about 16 million km2, an area greater that the area of Antarctica itself (about 13.2 million km2). The seasonal variability of sea ice, as well as the considerable change in day length, defines the background against which the life history of primary producers (e.g., phytoplankton), krill populations and their prey (such as sea birds and marine mammals) have evolved.

    For example, the life history of Adelie penguins include a 3 week courtship period, a month long incubation period where parents trade duties on the egg, hatching of the chicks and the subsequent task of feeding them (usually 2) until they are developed enough to leave the nest and face the world on their own. The success of a colony of breeding pairs of Adelie's can, each year, be measured by the average number of chicks successfully fledged (a number between zero and two) and this number is a rough indication of the overall ecosystem performance for the year. As might be expected, the success of the Adelie's (or any other plant & animal component of the ecosystem) depends upon a complex mix of physical, chemical and biological events. The scientists on the ship are testing several hypotheses that relate sea ice with this complex mix of events. In particular, this cruise is aimed at better understanding processes associated with the growth or formation of sea ice. A cruise 2 years from now will study the decay stage of sea ice.

    In order to accomplish the goals listed above, the plan of the cruise was to make physical, optical, chemical and biological observations of different sea ice stages, as well as of the water column and snow.

    The thirty-one people working as scientists on the ship are divided into seven groups, each with its specialty, working under a PI:

  • 1) Doug Martinson represents modeling and physical oceanography, and he and Rich are the ones who collect data from the CTD instrument which we send down into the water at regular intervals. Doug is also known for his inability to resist the delicious desserts made by Marta, and for his very funny summaries of operas...

  • 2) David Karl deals with microbiology and carbon flux in the water column. His group always rushes first to get at the CTD before any of us do, because they measure carbon dioxide and oxygen levels in the water, and we mustn't mess it up for them! David lives in Honolulu, and is very involved in trying to help solve the problem of feral cats abandoned on campus and in town. He feeds fifty or more of them, has them neutered and tagged, and is quite passionate about it: neat!

  • 3) Jinro comes from Japan, and works there and in New York. His specialty is studying the physical characteristics of ice. He becomes very excited when he sees a beautiful pancake! He has taken many core samples of ice, and even in weather like today's, when the swell is strong, he goes out in the zodiac with a few accomplices to trap a few unweary pancakes, measure them, take their temperature, and bring them back into his minus twenty degrees lab. There, with Tim, he slices them, analyzes them, photographs them... sometimes even melts them to learn more about them. He has been spending so much time in there, you'd expect him to be ice himself by now! Jinro has two claims to fame: he got married the day before leaving to come on this cruise, and he incurred the wrath of Neptune by claiming that the King might need cleansing as much as us poor neophytes: for that crime, he was sentenced to extra harsh treatment!

  • 4) Langdon Quetin and his group are the divers and krill specialists. They try and catch the little creatures under the ice or in the water column with a big net. I still shiver every time I see them disappear under the ice in the dark, freezing water, and keep my fingers crossed that they will not encounter a "sea leopard " (as they were called earlier). Reading "Endurance", I learned that leopard seals can weigh over a thousand pounds, chase other seals, penguins or humans on the ice, and happily catch them with their enormous jaws. Brrr... Langdon had the best 4th of July outfit during our barbecue: over his long underwear, he sported colorful shorts and a hawaiian shirt!

  • 5) Eric and Peter make up the birds and mammals team. They seem to have binoculars almost permanently glued to their eyes when they are up on the bridge, in hope of catching sight of any animal within a two miles radius. Since their job can only be accomplished in daylight, they get kidded about their choice of the Antarctic winter to come and work... Eric also hears comments from time to time about his (charming) Australian accent, but he has no trouble coming back with a witty reply, so beware!

  • 6) Maria Vernet, who is originally from Argentina, studies phytoplankton presence and concentration in the ice and water column. Her group goes through an amazing quantity of water from the CTD, and is often accused (jokingly) of not leaving any for the rest of us. Besides working in the main lab, they also hide in a little dark room where they do observations under the microscope, and they have a trailer on the helo deck, where they deal in radioactive materials: dangerous bunch! A few days ago, as we were all excited about the beauty of Jenny Island in the moonlight, Maria was overheard to tell Brian "go look at... the beautiful ice samples we have collected!" That's being in love with your work!

  • 7) The last group, to which I belong, is headed by Ray Smith, who is also the main PI on this cruise, with the responsibility of coordinating all the various experiments. of being the link between the Captain and his crew and the scientists, of planning ahead the route and the scientific events (we've had close to two hundred at this point), and of keeping a record of everything accomplished. Sometimes a twenty-four hour a day commitment! The group's experiments have to do with the optics of snow and ice in its various stages of formation, as well as measuring how much biology is entrapped in the ice. For this purpose, besides taking water and ice samples either by hand or with the CTD, other instruments known a "PRR" or "frazil meter" or "ROV" (do you really want to know what those stand for?) are often dropped into the water. David M. is the miracle worker of the group who fights the fits of malfunctioning which seem to affect the machines regularly.

    A couple of days ago, I observed Langdon's group (Tracy, Jenny, Jared, James, Matt and Stephanie) as they pulled out their net: I had not had a chance to do that before. Langdon and his group are the divers, but they also sample what's in the water by lowering a large net behind the ship, and letting it be slowly dragged for about an hour. This device is called a "MOCNESS", which is an acronym for "multiple opening/closing net environmental sensing system" (say that ten times fast!).

    Seen from above, it looks like a weird monstrous octopus, since the main net is divided into a series of smaller "arms", each ending with a "basket" which traps what unlucky little creatures were in its path. The net is first lowered closed to a certain depth (usually about 320 meters) then as it is pulled back up, each of its eight baskets can be triggered at a chosen depth: that gives an idea of the distribution of the catch in the water column.

    Once the net has been brought back on the deck, and disconnected, the containers are put into pails and carried inside the lab, where their contents are identified, counted,measured, and examined under the microscope.

    I asked Langdon what they had mostly caught, and he answered krill, krill larvae, salps, ctenophores and siphonophores. The day I was there, there had been quite a number of krill caught, and excitement was in the air: the krill had been conspicuously absent so far! Salps are strange animals made of a jelly-like substance, and their shape is that of a tube, through which water flows as they swim. A filtering membrane catches phytoplankton, which constitutes their food. That is why, after Langdon's group is done counting the salps, they hand them over to Maria, who studies the phytoplankton. More about her later...

    Next to the lab where all this happens is another room called the "aquarium" room. In there are several small tanks, where krill larvae can be kept and their rate of growth observed and measured.

    I have talked several times before about "the bird people", Eric and Peter. Despite their nickname, they not only observe and count birds, but also marine mammals, seals and whales. This cruise has been "lean" for them, since we have not found very many animals of any kind, except for a few hundred Adelies. Even with them, Eric and Peter were not able to do as much as they wanted: not allowed to catch them on Dion Island, they tried to go to Ginger Island to pump a few more stomachs, but the fog and the ice moved in suddenly, and we had to pick them up from the zodiac sooner than planned.

    Like each profession, the bird specialists have their own jargon, some of which may be surprising to the non initiated: how many times have you heard someone calmly state, over breakfast, "today, I'd like to regurgitate, if possible"... which of course, means pumping penguins' stomachs!

    Well, enough for today, I will tell you about the other groups in the next few days. Happy belated 4th of July!

    PS: picture: the MOCNESS being emptied of its contents.