Karen's Daily Blog

A new list of potential Extreme Experiments appeared in my computer in-box this morning, including a suggestion from Memorial High School in Eau Claire, Wisconsin: Can bacteria taken from hydrothermal vents live when taken away and moved closer to the surface?

Really good question! “I’d be curious to see if they can live up here, but more interested in how bacteria functions in their normal environment,” Extreme scientist Kathy Coyne of UDel says. We decided to use her protist project to demonstrate how experiments are set up on the ship with organisms from the hydrothermal vent environment. (Check out yesterday’s Extreme Blog to learn more about Kathy. )  Kathy pointed out that the key thing in science is to observe (so Memorial was on the right track in suggesting studying bacteria under a microscope), and that the second step is to come up with a hypothesis to explain what you’re observing. Once you have that, then you can design experiments to test your hypothesis. Sometimes your answer is negative, so you know your hypothesis is wrong, and you go back to the old drawing board.

Kathy talks about Team Protist’s (Dave Caron’s lab) observation last year when they found that many of the protists at Guaymas Basin were ciliates (a particular kind of one-celled organism).  “I wondered what function ciliates play. Are they grazing only on certain bacteria, or just on anything they can find?”

Kathy Coyne pictured above.

 

If you read Kathy’s blog yesterday, you’ll remember that most of her sample protists come from the local bays and estuaries in Delaware. With vent animals, you can’t just experiment at our near the place where your samples live naturally, so you have to design an experiment that mimics vent conditions, such as pressure. Kathy found a way to use a pressure chamber to test her ciliates at pressure.

Her next challenge was to find something for the ciliates to eat. Craig Cary suggested using (one micron) magnetic beads – about the size of bacteria – that were coated with proteins to fool ciliates into thinking they were food. If some of the ciliates eat them, you can use a magnet to find out which ones did the eating, because the magnets will pull the ciliates toward it.

Kathy’s plan involved bringing Riftia (tubeworms) tubes up from the ocean floor.  She scraped the inside and outside of the tube to remove the film of biota (called the biofilm) from the tubes, mixing the tube and biofilm (which included ciliates) together into a soup with sterile, filtered sea water.  During this time the ciliates weren’t at the pressure they would naturally be in at the vents. It took Kathy about two hours to make her “soup,” add magnetic beads to it, and place it under pressure in tiny bulbs. She used a hair straightening wand to seal them.  Then she put the bulbs into the pressure chamber for the next 20 hours. (Note that as a control, Kathy killed whatever was living in five of her tubes with formalin. )

The next day she took the bulbs out of the pressure bomb, applied a magnet to the side of each, then rinsed off anything that was not stuck to the magnet. Anything that hadn’t eaten a bead, and dead things that hadn’t eaten a bead were all rinsed to ensure that the magnet didn’t attract anything else but ciliates with a magnetic beads inside their miniscule guts.

It worked!  “YES,” says Kathy.  “In the five live ones there were ciliates, whereas there were no ciliates or protists in the dead mix. This shows that when I do the experiment, I’m not pulling out things that didn’t eat the beads.

Today’s dive was scrubbed again because there are just too many big waves out there to allow Alvin to dive safely. If we do get to go down tomorrow and gather more samples, Kathy has a plan for how to expand her experiment. “I’ll do the same thing, but this time  I’ll analyze the solution with all the biofilm and all the ciliates and everything to see what bacteria are present in that solution and compare that to bacteria that were eaten by the ciliates by the end of the experiment.” Her results can be used by other scientists who want to see a complete picture of how each organism fits into the vent food chain. “We can detect what bacteria are in the solution initially, then later compare that to the ones that have been grazed: what has been eaten compared to what hasn’t.”

Today's Extreme Blogger:
Conrad Pilditch

0740 h Saturday Nov 15 on board the Atlantis and I was climbing into Alvin , about to embark on an adventure to one of the last remaining frontiers on the planet, the deep-sea.  Southwest of the ship, a long way southwest, on the other side of the Pacific Ocean (and the international dateline) in New Zealand, it was 2:40 am on Sunday morning and in a few hours my son would be waking to celebrate his 7th birthday.  He was really excited, a level of excitement that had been building to fever pitch since mid-October when the unofficial birthday countdown begins (the official ‘mum and dad’ countdown begins the day before).  As I was getting into Alvin to spend a day at the bottom of sea, I found myself experiencing those same childhood levels of excitement and anticipation. To quote my now 7 year-old son, this was going to be ‘one of the best days ever’.       

So how does a scientist from New Zealand get from there to here?  Well by aeroplane of course, not just one but several.  The first plane trip was the one my family took to New Zealand when I was five --  a good move mum and dad because it meant I got to grow up on the pristine east coast of the North Island.  During my school years I developed a passion for diving and exploring the coastal waters around our home.  When I left high school I knew I wanted to be a marine scientist, with the grand aim of finding someone to pay me to do my hobby.  After several more plane rides and ten years of study at New Zealand and Canadian Universities, I had a job at the University of Waikato in New Zealand where finally, much to the relief of my family and the bank, someone was actually going to pay me to study the sea.

I have been at Waikato now for ten years, where I teach marine ecology and oceanography.  My research looks at soft sediment ecosystems, the sand and muddy sediments that comprise the single largest habitat on earth.  These sediments support an incredible diversity of organisms (such as worms, crabs and shellfish) and the transformations occurring in these sediments affect global carbon budgets and the productivity of the overlying water by supplying nutrients essential for plant growth.  In coastal waters this ecosystem is amongst the most impacted by human activities; it is the final resting place of many pollutants and is disturbed by dredging for coastal development and fishing activities.  My main focus has been on how the activities of animals that live in the sediment affect the exchange of materials to and from the water column.  Together with graduate students we have been interested in how these animals influence sediment movement, nutrient exchanges and the settlement of newly arriving species.   Like most soft sediment ecologists, the majority of my work has been conducted in the comparatively shallow coastal waters close to home and not the deep sea, a real shame given that nearly 62 % of the Earth’s surface lies 1 km below the surface.   A combination of factors results in this basis bias?; funding for research tends to focus on human impacts which are most acute in coastal environments and most commercial fish species that feed on animals in the sediments live in shallower waters.  Accessibility is also a big factor as is cost; it is  very expensive and difficult to work in the deep sea.

About eight years ago I was lucky enough to become involved with a group of scientists from New Zealand who were studying deep-sea environments.  Our research examines the connectivity between animal biodiversity and biomass in the sediments and their food source, the plant production in surface waters which eventually settles to the sea bed.  The goal of this work is to gain a better understanding of the fate of carbon incorporated by the small oceanic plants (called phytoplankton) during photosynthesis, an important link in the global carbon budget.  During the last several years I have participated in a number of research voyages on board New Zealand’s only blue water research vessel theTangaroa (named after the Maori god of the sea).  The Tangaroa is a modern very well equipped research vessel but it has no submarine capable of taking scientists to the ocean floor.  While we can learn much from towed video/camera systems and dredging the sea bed, to see it with one’s own eyes is truly wondrous.  In my mind camera images are always filtered (e.g. by the person operating the camera, or by the field of view) and nothing can compare to actually seeing and experiencing something with one’s own eyes.  About the same time I started working in deep sea environments Craig Cary was on sabbatical at the University of Waikato.  After Craig’s departmental seminar began several years of subtle “I would be really interested in participating in one of your hydrothermal vent cruises” and not so subtle “I really, really, really want to go” and even in the eyes of some, behaviour that could be classified as down right grovelling.  So it was with great excitement when earlier this year Craig indicated he needed help in the lab on his Extreme 08 Voyage and would I like to go.  Another plane ride (actually two) and I was on board the Atlantis heading for the hydrothermal vent field at 9° N.

Deep-sea clams.

 

So was my trip the sea bed onboard Alvin ‘one of the best days ever’? You bet!   To see right outside the window of Alvin a few feet away chimneys spewing forth super-heated water and the abundance of life colonising the newly formed sea floor, incredible.  What no camera can catch is clarity and intensity of the colour, the bright red plumes of Rifta, the whiteness of the scavenging crabs and bright yellow mussels against the black basalt.  The trip down and up was also spectacular. Around 1000 m we passed through a layer of bright blue bioluminescence that looked like thousands of tiny lights switching on and off.  The dive also gave me a start on some preliminary research examining the chemical composition of vent clam and mussel shells to see whether they can provide a record of environmental variation (a little like looking at tree growth rings).    The completion of my first dive was  made especially memorable by my colleagues in the lab: the iced water bath was shocking but the coffee grind shampoo was an inspirational touch.  I really hope they all get the opportunity to experience life at 2500 m, and if they do rest assured I will be waiting for them topside with a suitable reception.   Now the real question is how can we get a submarine down under to explore the hydrothermal vent fields in New Zealand waters?  

Photo Gallery

Clamming up!

Video Gallery