Thursday, May 29, 2014

Canadians, eh?

left to right: Dr. Mark Wells (U. Maine), Trey Joyner,
Dr. Charlie Trick (Western U.), and Dr. Bill Cochlan (RTC-SFSU)
As a southern boy, I haven't had too many encounters with our friends north of the border. Now, I find myself talking hockey and comparing climates of our homes with three of the four principal investigators: Dr. Cochlan, Dr. Wells, and Dr. Trick. All three of these men of science hail from the colder regions of North America and are proud of it. Dr. Wells lives and works in the States at the University of Maine, and Dr. Cochlan lives and works in California at San Francisco State University. Dr. Charlie Trick, however, continues to live and work in the great Dominion of Canada at Western University in London, Ontario, but was raised in Ohio.

Dr. Charlie Trick proving that fun and science do mix!
This group has been incredible, and it stems from the leadership.
I will be writing more about Dr. Trick in the near future, so I will concentrate on the complimentary work that he and his team from Western U. are doing in our oceanic lab at sea. Julia Matheson, "PJ," as she's known onboard, is a graduate with her master's degree in biology. She has been brought on by Dr. Trick to be his research assistant because of her experience with a sophisticated machine, called a "flow cytometer." Julia quietly works all day from her station, donning heavy jackets in the cold lab. With every 2 mL sample, she uses the flow cytometer to determine the phytoplankton species and concentration. While I was interviewing her, she showed me that the sample in her hand had 19 cells of the raphidophyteHeterosigma akashiwo a species known for forming harmful algal blooms ("red tides"), a fish killer. That means that the concentration of the sample contains 19 of these harmful cells per 100 mL of seawater. The PI's will analyze these results and the results of others to determine a possible conclusion, but they never jump to conclusions. Just like in my classes, they rely on the evidence to guide them, and just like my classes, they use multiple sources.

Julia Matheson, research assistant, Western University,
London, Ontario, will be spending 12 weeks after
our research at sea in Bermuda with BIOS, Bermuda
Institute of Ocean Sciences as an intern with more time at
sea on the R/V Atlantis.
Julia is basically determining the same thing as Brian and Kathryn (see previous post) but using laser technology rather than traditional light microscopy. Both parties are observing the assemblage of the type and concentration of the phytoplankton in each sample. Brian and Kathryn are using concentration techniques, then, looking under the microscope for the general abundance of the phytoplankton present. Julia is using the flow cytometer which automatically sorts the cells by size and chlorophyll fluorescence, essentially observing the same things as Brian and Kathryn. From these two sources, the PI's can be sure that they have an accurate view of the biodiversity of the ocean's primary producers. Julia's machine also allows her to breakdown each sample into high, medium, and low chlorophyll production for each cast and each depth sampled. This is additional information to be shared with the teams to assess the relative health of the planktonic community.

Speaking with Dr. Trick, I realized that the food chain communities are size-based assemblages. In other words, large planktonic cells are food for larger zooplankton. The larger the phytoplankton, the shorter the food web, making it more efficient energetically. If phytoplankton cells, due to oceanic acidification or other variables, are smaller in size, then the food chain is longer, less efficient, meaning that more sun and nutrients will be necessary to provide the same amount of food for fish and other predators at the top of the food chain. Therefore, it is important to find out the cell size and their relative photosynthetic contribution to the natural community. And, like the iPhone, there's an app for that; in fact, there are multiple tools available that our marine scientists utilize aboard the R/V Melville.

Andrew Schellenbach, senior at Western University with
Dr. Cochlan (RTC-SFSU) and Denis Costello and
Kathryn Ferguson in the background.
Andrew Schellenbach, our youngest science crew member at 20 years of age, is a senior at Western Univ., and hopes to use this experience to help guide him in the next chapter of life as he continues his scientific career. His job in this investigation has been to use two types of fluorometers, one approach uses a chemical, called DCMU to disrupt the flow of photosynthetic energy and then measure the fluoresence using a traditional fluorometer; and in another approach, rapid rates of light are used to saturate the photosystems of the planktonic cells. This latter type of fluorometer is called a FIRe. By firing light through the samples, FIRe is able to provide a measure of photosynthetic health--determining whether we have "healthy, happy cells or distressed, sad cells," according to Dr. Trick, co-PI. Andrew explained that FIRe uses a ratio from two different blasts of light, one short and intense, another longer, less intense. The light excites the photosynthetic cells until they are saturated. With each specific ray of light, FIRe records the cells' absorption of light until, no more light can be absorbed; it is saturated. Andrew's analysis using these two methods compliment another experiment onboard that goes even a step further. I will focus on Chuck and the "Radvan" later and show how it provides more evidence from yet another source to determine the health of the phytoplankton in our samples.
FIRe measures photosynthetic health from the ratio derived
from maximums that saturate the cell.

With every experiment, with every method, with every collaboration and with every conversation; together - they reveal a clearer picture. Like observing a diamond from different angles, using different instruments and different eyes, we not only have a better understanding but a greater appreciation for its beauty. Personally, that is what I'm observing here everyday at sea: Beautiful complexity revealed one test at a time.

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