Rory Blaisdell
Phytoplankton Biomass Sampling
11/18/09
Hi my name is Rory Blaisdell and I’m from Bell High School in Ottawa,
Ontario. I was very excited for this trip, especially being able to work hands on with
the scientists doing real experiments and sampling. One of the most interesting and
“real” experiments the other students and I did, was a test for biomass of
phytoplankton in the water column of two different fiords. We were looking to
calculate the biomass per cubic meter, so we could have an idea about the
productivity of the ecosystem. The way we did this was by analyzing samples for in
situ fluorescence. The chlorophyll a of the phytoplankton gives off fluorescence, so
we use it to calculate the total biomass. We started by splitting into groups, one for
each of the two selected fiords. Late at night with the help of Dominique Boisvert
(INRF) and Joannie Ferland (UQAR) we deployed the Rosette (an instrument used
for measuring and sampling the water column) to the ocean floor and took samples
where, real time, we noticed changes in the fluorescence levels of the water column.
We took these samples back to the lab and filtered each of the different water depth
samples. In filtering them, we ended up with the actual matter; the “bio-mass” of
phytoplankton. We left these samples to sit 18 hours in acetone; this was to extract
the pigment from the samples, leaving us with just the chlorophyll a
We went back to the lab the next day to analyze our samples further, to
measure the fluorescence. We turned off all the lights because it would affect our
measurements, and we stuck the samples (in test tubes) into a flourometer. We
carefully recorded the measurements of fluorescence in each of our different
samples. We then added hydrochloric acid to the samples and measured again. This
was to kill off all the still living components of the sample. Doing this allowed us to
measure not only the total biomass of phytoplankton in that depth of the water
column, but also to measure the degraded pigment within that depth. This gave us
the health of the community at each depth. The final result was a table of data with
numbers that didn’t mean anything to us. Joannie gave us the formulas, and we sat
down to crunch out the results.
It was very satisfying that a couple hours later we had the exact biomass of
phytoplankton at different depths of the water column in each of the two fiords. It
was great to have a tangible result. We could look at the population of
phytoplankton in both of the two fiords and talk about causal relationships between
biomass, and the other environmental factors; the measurements of which were
recorded by the Rosette as we took the samples.
Although our work did not give any scientist a “conclusion” or make any
great discovery, it did add to the data, and will be used in the future to help with an
experiment, or support a hypothesis. Engaging in this “hands on” experiment with
the scientists was a lot of fun, and very rewarding. The late night sampling and lab
work was very worthwhile, and I felt as if I had actually contributed to someone’s
professional work. We got to see the “fruits of our labors” in actual results, and see
what our experiment had come up with. It was definitely worthwhile, very
educational, and above all, my favorite activity onboard the ship.