A diverse research team aboard the U.S. Coast Guard Cutter (USCGC) Healy will conduct sampling along a series of transects over the eastern Bering Sea. Research on the ship is multidisciplinary, with scientists using a variety of techniques to document ocean conditions and the productivity of the Bering Sea ecosystem. Research teams measure the temperature, salinity, and nutrient content of the sea water, changes in sea ice cover, and the concentration of nutrients used and released by phytoplankton. They also conduct surveys of zooplankton, fish, seabirds, and marine mammals such as walrus and seal to assess the health of these populations. A major focus of this cruise is characterizing the phytoplankton bloom associated with the edge of the melting sea ice.
What is plankton? Why is it important everywhere from the Arctic to your local waterway? Let’s catch some females and see if they will lay eggs in our own plankton reproduction study!
"Glad to be back?" One of the first questions that people ask (before "Did you see a polar bear?" and "Did you ever grow your sea legs?") is the hardest to answer. Yes, I am happy to be back in a place with greenery, excited for sun-dresses, ready for bike riding and psyched to see all my students but there's definitely a cultural integration process that goes along with reentry into life post-Healy. Some of the things that have taken some getting used to are the following...
1. There's no "Red Goat" garbage disposal in the school cafeteria for me to accidentally throw metal objects into. 2. My clothes come out much cleaner with Tide than the detergent that doubles as deck cleaner. (At least they smell cleaner). 3. My pager doesn't go off at three am. Oh right, I have no pager. 4. I can't use "I'm in the middle of the Bering Sea" as an excuse for delayed email responses. 5. If I don't go grocery shopping and cook, then good, hot meals don't magically appear at mealtimes. ? It's true. 6. There are no scientists in my classroom to answer all my questions about the world. 7. I don't have to use two hands on the stairs but I can't slide down the rails either. 8. Commuting via subway takes much longer than the trip from my room to the lab. 9. There are no walruses. 10. There are definitely no fun, watertight doors or restricted elevators!
My first class back on my third day home had 50 students in it. Mission: Dissecting shrimp a la the Healy krill team! The kids even cut off some eyes! We certainly hit the ground running.
Summer is almost here though so I will have time to regroup, get used to falling asleep without the rocking of the boat and soak in everything that I learned, saw and did in my 40 days of ice, science and plankton. Stay tuned...
Suiting up in an MSD-900 survival suit felt a little bit strange considering that there was no ice for as far as the eye could see. We were miles from the ice-edge as we pulled into Dutch Harbor but there I was pulling and squirming back through the many zippers and pull-ties. This time I would not be waiting to clunk down the brow in my bunny boots towards the ice though. This time... I was going in the "small boat"!
The Healy 2, or the "small boat"; as it is affectionately referred to by its crew, usually hangs unobtrusively above the portside 03 deck. When sediment traps need to be retrieved, a buoy needs to be checked on or a small crew needs to go into port first, she is lowered from the top of the boat into the water. This is when the fun begins! As the Healy pulled slowly into Dutch Harbor on Monday, a crew of three boatswains was sent ahead to act as the land crew, manning the lines that tie the Healy in place at the dock. I was lucky enough to tag along!
Getting dressed for the ride was no joke, as usual. First, there was the MSD-900, then the PDF (personal floatation device, aka life-preserver). Finally, the helmet as an accessory. Once we were dressed for the party, we squatted on the deck of Healy 2, and held onto the safety lines and she was lowered down into the water with a thud.
Boatswains Andy Yeckley and Jim Merten were behind the driver's console as we sped away from the Healy. Flying across the water was amazing enough until I realized that Andy was going to let ME drive!
Luckily there's no stop signs, traffic lights or speed limits when you are behind the wheel of the small boat but otherwise it is just like driving a car. I revved it up, turned the wheel and soon we were flying towards the port. The sun was shining, the mountains looked crisp still covered in snow and the Tufted-puffins that were feeding in the water around us seemed to be welcoming our arrival back to land! When Healy pulled in thirty minutes later, everyone was out on the deck celebrating the chance to call their families, go on a hike and just get off the boat! Take a look at the work that went in to keeping the Healy from floating away...
While I am happy to go for a run on a solid surface that isn't rocking in the waves, hike up snowy mountains in Dutch Harbor and eat fresh fruit, I am sad to be leaving the bustling science lab, the Healy crew and Bering Sea adventure behind! Tomorrow, I will start the trek home, armed with a bag of Bering Sea mud, a jar of brittle stars, and my pet copepods in tow. My favorite scientists at Oyster-Adams Elementary- I will see you soon!
Alexei Pinchuk peers into a clear plastic bottle that he has taken out of the fridge outside the lab. If you didn't know better, you would think that he was looking at a bottle of chilly water. What he is actually doing is checking on his babies...his baby krill, that is. Looking closely into the bottle I can see three teeny organisms swimming around. Each of them is smaller than a grain of rice and as clear as cellophane. The only colors visible are a little pink dot by their tail and a green spot, in the middle. This green stuff tells Alexei that these one month-old krill have been busy eating. He hopes this means that they will continue to grow.
So why does Alexei, a scientist at the University of Alaska, have a fridge full of krill babies? His role as a member of the nocturnal krill team is that of Poppa Krill. By harvesting gravid (pregnant) females from the various tows each night, he hopes to obtain eggs and raise the babies. He works with the University of Maryland researchers that are trying to establish an index for identifying the age of krill. Right now, the scientists can compare the ages of different krill, or establish relative age, but there is no way to know their exact age. Using Alexei's krill, the UMD team will then be able to look for age-tracers in a population of krill that they know the age of for certain.
Female krill turn blue when they are ready to reproduce. This is a pretty good signal for Alexei when he is deciding whom to keep for his study. "The tricky part is getting the gravid females and then getting the eggs.", he explains. He collects these blue ladies in the hopes that they will follow through and lay eggs. On this trip he has gotten his wish. He has successfully collected eggs, which have now hatched into young krill. This is what he was watching swim around in the refrigerator bottles while I talked to him yesterday. These guys were one month old and still developing. In fact, they hadn't even developed eyes yet! Can you imagine a one month-old baby not being able to see yet?!
Krill, it turns out, are pretty complex and delicate animals. They go through many life stages and successive molts before reaching maturity. Many different variables factor into their ability to successfully grow and reproduce. The most important of these are temperature (when they are very young) and availability of quality food (when they are older). Molting and reproduction are high-energy activities so without proper food stores in the form of lipids (fats), it's not likely that development will be successful.
Alexei's personal research interests are not limited to krill, however. He also studies plankton. He uses two netting systems to collect his samples. The Calvets look like a pair of pants when they go into the water off the back deck. Two long nets follow the figure-eight shaped frame as it is towed behind the ship. He investigates plankton abundance, biomass (how much, how dense) and distribution (how far it is spread out).
In search of still more plankton, I found myself on the fantail again at 1:30am with Alexei's second kind of sampling net, the MocNess. The MocNess is a contraption that few people on the cruise have ever even seen operate. It sits shrouded in its own nets on the back deck, silently waiting for Alexei to unwrap it and send it out in search of plankton. The nets on the MocNess are much finer than most of the other towing contraptions. The finer mesh allows for more animals to get caught in it. It also reduces the amount of water pressure that the little animal bodies are battered with as the net drags through the water. These nets pull up animal samples that are relatively unharmed.
We deployed the MocNess off the fantail in a May snow-shower and then headed up to the control center where Alexei monitored how fast the ship was traveling, how much volume was traveling through the nets and how quickly the whole contraption was moving through the water. By communicating with the boat driver, he could make small adjustments to ensure that he was collecting the samples that he wanted. Meanwhile, the MocNess was drifting silently deeper and deeper. At each station, Alexei watches its movements carefully through remote sensors and decides which depths he wants to take samples from. By closing the series of nets at different depths, he can capture representative samples at different spots in the water column.
Once the nets come back on deck, the cod ends (the bottles at the end of the nets) are snapped off and the samples are filtered. Take a look at what we caught last night...
We're not done yet though! Resetting the nets means reversing the process with the cod ends (re-snapping them into place), replacing the nets and then snapping in a series of release bars. At 3:00am we were ready and in place for the second tow which was only one station and 30 minutes away! The propellers went to work and we steered in the direction of the next sample station two miles away through the dark and chilly waters...
So where in the world does a producer eat other animals, a consumer make its own food and sometimes either will decide to do both? Welcome to the wacky world of the Bering Sea ecosystem!
In theory, there are two main categories of eaters- heterotrophs and autotrophs. These are basically the producers and consumers. Autotrophs have the ability to make their own food. Heterotrophs need to consume energy from other sources.
Mixotrophs throw a monkey wrench into the neat order of this organizational system. Mix-o-troph- the name even sounds "mixed-up"! These guys are the flexitarians of the plankton world. Generally, they have dominant behavior in one of the first two categories. This is how the mixing part happens...
Heterotrophs, the ones that eat for energy, often consume plants. Plants carry out photosynthesis in chloroplasts by manufacturing chlorophyll. Through a process called "kleptochloroplasty", some heterotrophs can consume a chloroplast-producing organism, incorporate the cells into their own body and then begin producing chlorophyll themselves. Crazy, huh? Eat a plant, make the cells your own and then start making your own food with these cells!
The craziness doesn't end there...some autotrophs, namely phytoplankton, can act like heterotrophs when the going gets tough. In times of low light, when production is reduced, these guys start to eat each other. Yes, plants eating other plants!
Celia Ross and Julie Arrington, both from Oregon State University, have spent their time on the cruise sorting through this complex world. To make it even more confusing, they have to do it in the dark. The best way to tell whether something microscopic is a heterotroph is to search for an autotroph that it has consumed. In order to do this, though, they have to be looked at with a special blue light. By shining this light through a water sample, Celia and Julie can see the chlorophyll glowing red. They can then zone in on which of the plankton in their water sample are heterotrophs by looking into their bellies. Is it glowing? Then it has eaten something green and growing!
I stumbled into the main lab at 10.30 pm last night, already a little sleepy from a day of webcasting, multicoring and VanVeen grabbing. I was tired but determined to stay up with the mysterious Krill Gang for the night before I ran out of days to do it. The first person I found hovered above a microscope was Tracy Shaw, a technician at NOAA's Hatfield Marine Science Center in Oregon. Fresh from a day of sleep, her workday was just getting warmed up as most of the ship was heading to bed. At her workstation a Tupperware was swimming with krill that she has been experimenting with almost a month. These little guys have been very hungry. They are unwilling participants in a "starvation experiment" that she has been carrying out as part of an overall look at how krill live in the Bering Sea and what they eat along the way. The starvation part is important because they are looking to find out how long certain foods take to show up in the krill's body composition. They want to know how the body composition changes over time in the days after they eat a certain food. This way they will be able to tell what and when the krill that they catch have eaten. The inhabitants of Tracy's bowl had feasted on a buffet of ice algae and now they were ready to be measured.
Krill are "vertical migrators", meaning that they travel up through the water column at night to feed in the dark. In order to study these guys while they feed, the scientists that study them have to adapt their sleep schedule to work "krill hours". These are a far cry from banker's hours. The krill team comes up at night to feed too. Breakfast for these guys is usually after most people aboard the Healy have eaten dinner. At 11.00pm the night-shifters convene in the Mess Hall to eat "mid-rats" (the late dinner) together. This is just the beginning though. Bongos go out at 2am and there's work to be done beforehand.
Last night, I was in the lab and on the fantail at some pretty ridiculous hours to find out what the vertical migrators and their night-owl scientists do in the wee hours!
While Tracy is trying to find out what these critters eat, other members of the team are working to solve other mysteries.
Who's out there? Dr. Evelyn Lessard, from University of Washington is the Co-Chief Scientist for the cruise. She is also the head of Team Krill. As a microplankton ecologist, she generally studies organisms much smaller than krill but aboard the Healy she is interested not only in the plankton but in their relationship to the krill population. Before the cruise begins, Evelyn knows what types of experiments she will be conducting. Each sample is unique though. When a water sample comes off the CTD, it's only a guess which investigations will be appropriate for what's in that sample. That's where her FlowCam comes in. By taking a small sample of the seawater and running it through this instrument, Evelyn can tell right away who or what she's got in there.
Once she has a peek into the microscopic world in the sample, she can make decisions about which kinds of experiments she will learn the most from. So what does she see through this magical FlowCam? Using a white light, a green laser and a digital camera, this mega-microscope captures pictures of plankton that you can't easily see. These guys are small and beautiful!
Even an expert like Evelyn will admit that the microzooplankton world is a very confused one. Organisms that seem like plants eat other organisms. Organisms that seem like animals produce their own food and there are even organisms that no one knows how to classify yet! (More on all this later). During Evelyn's career much has been discovered. She says, "One of the exciting things about my field is that when I started [microzooplankton] had been virtually ignored because when you pull up a net you can't see them!" Luckily, Evelyn can see, sort, classify and discover them.
So what's this have to do with krill? The big picture in the krill department is the idea that by looking at the population from many different angles, the team will get an idea of population dynamics under different conditions. Evelyn explains what the main idea is, "We are trying to determine how critical the ice is to their survival." Each member of the team has their own question work on so that they can contribute their data to the krill-conversation.
How old are they? Dr. Rodger Harvey and Rachel Pleuthner are from the University of Maryland, not so far from Oyster-Adams School! Rachel was breaking down her workstation when I arrived in the lab. As we near the end of the cruise, experiments are being packed away little by little. Until now, Rachel and Rodger have spent the last five weeks staring deep into krill eyes. Eye tissue is one of the places that krill accumulate a substance called "lipofusion". Lipofusion is a waste product that piles up over time in neural tissues. The older the krill, the more there is. But how old? That's what their team hopes to figure out. By working with another scientist (stay tuned to find about Alexei Pinchuk), who will begin raising krill, Rachel and Rodger are trying to establish an index for how much lipofusion indicates a certain age. Why is this important? By looking at the population of krill for a given year, biologists can identify environmental influences on the population. This can help answer questions like- Was there enough food in the past year to allow krill to get healthy enough to reproduce? Or...How old does the average adult get? Knowing how old or young a population is helps the krill team to understand the lifecycle, environment and dynamics of the communities.
Who Eats What? Meanwhile, Gigi Engel is bundled up, hovering over a tray of microscopic organisms with a "Crazy Straw" in her mouth. She is looking for "protists", single-celled organisms like phytoplankton, microzooplankton, ciliates and dinoflagellates. These itty-bitty consumers often have something called "biomarkers" that help identify them. The biomarkers are lipids, or fats that are unique to certain organisms. Once these little guys get eaten by predators, the "biomarkers" turn up in bigger organisms, Looking for these markers can help biologists and ecologists understand the connections in the food web. This type of tracing has been done in other populations but according to Gigi, no one has really explored it in protists yet. "That's where I come in," she says. She is capturing cells in a filter lodged in her crazy straw-looking device. Next week, she will take these little pets back to Seattle with her and continue her work.
After 21 hours of science, my brain had taken in all it could handle. Four in the morning is way past my usual bedtime but the Healy is definitely an unusual place! Stay tuned, there's five days to go and you never know what could happen next!
Yesterday we bid farewell to the ice and it was a perfect finale! After backing and ramming for hours to travel just a few miles through intensely thick ice that rocked the boat with its "rubble fields" and "ridges", we arrived at our final ice station!
Gloveless and sporting t-shirts under our MSD900s we hit the brow ready to drill cores and collect samples for one last glorious day before real spring takes hold and the sea ice begins to disappear into open-ocean.
We wanted to stall, drill just a few more cores, collect a few extra samples... any reason to stay off the boat but eventually we did have to get back on board. We are now headed back into the excitement of the bloom with the frenzy of activity that accompanies it. I will miss the ice but I sure won't miss getting dressed for it!...
[video]
Yesterday we bid farewell to the ice and it was a perfect finale!
