While everyone onboard has a love for the ocean, our
specific interests are pretty diverse. Many
of our scientists are focusing on the different chemical compounds in seawater
to explore biogeochemical processes, trace water masses, and examine inorganic
chemical processes occurring in these waters.
Some scientists are in charge of deploying instruments that collect data
of the relative motion and heat exchanged between local water parcels. There are also a number of scientists onboard
who are interested in studying seawater from a biological perspective, from examining
the DNA to investigating the community structure of marine microorganisms.
Steven Baer, a postdoctoral researcher at the Bigelow
Laboratory for Ocean Science, is studying phytoplankton ecology and
biogeochemistry onboard. He’s part of a
team of four (more on the Bigelow/UCI Lab Group to come!) who collect seawater
from the surface ocean down to a depth of around 200 meters – the layer of the
ocean where they expect to have the greatest signs of productivity in the ocean. They filter the seawater to collect
microscopic evidence of life.
 |
[On the aft deck, Steve prepares his samples for analysis.]
|
From Steven Baer:
I’m broadly interested in how phytoplankton make a living,
and their impacts on nutrient cycling in the ocean. This means I do a
number of different types of experiments to determine how microscopic organisms
compete for nutrition, and under what conditions different types of
phytoplankton succeed.
While phytoplankton
are small, they have an outsized impact on the biology and chemistry of our
planet... Because the oceans are so vast, marine phytoplankton account
for at least half of all the oxygen in the atmosphere! They have a major impact on the fluxes of the
primary elemental building blocks of life: carbon, nitrogen, and phosphorus.
However, because phytoplankton are so small, they can be
hard to find. Traditionally, oceanographers would spend a lot of time
looking at water samples under a microscope. With recent advances in
optics and processing power, we are now able to automate cell counting
procedures, specifically using something called a FlowCAM. This
instrument is akin to something called a flow cytometer, which allows us to
enumerate small cells quickly. Basically, we pass a narrow volume of
water past a laser. When the laser hits a cell with chlorophyll in it, it
is picked up by a detector and a picture is taken. It can do this for
large volumes of water, and very accurately.
 |
[Laser light of the FlowCam system]
|
This method is an improvement over the microscope, which would
require a lot of time and expertise to get an accurate count of microorganisms.
In this case, we can detect cells in the range of approximately 5-300
microns. For comparison, the width of
human hair is about 6 microns, and 1 micron (micrometer) = 1x10-6 =
0.000001 meters! For phytoplankton (and bacteria) that are smaller (which
is most of them here in the surface of the Indian Ocean), we take samples back
to the lab on shore and analyze them with an even more powerful laser and
instrument setup.
Below, Steve works in the BioLab onboard and preps his
FlowCam to capture images of marine microorganisms.
 |
| [Images of plankton cells recorded by the FlowCam on 4/2/16] |
This comment has been removed by the author.
ReplyDelete