Posted on by Teacher at Sea

Jillian Worssam, July 23, 2008


NOAA Teacher at Sea
Jillian Worssam
Onboard U.S. Coast Guard Vessel Healy
July 1 – 30, 2008

Mission: Bering Sea Ecosystem Survey
Geographic Region: Bering Sea, Alaska
Date: July 23, 2008

Last night I went to bed at four, my wake up call was for seven forty five this morning, needless to say if I have a little difficulty explaining micro-zooplankton there is an excuse.Today I am spending time with Diane Stoeker and Kristen Blattner, both from The University of Maryland Center for Environmental Science.

If she is not at the computer Diane is either at the microscope, the incubators or working on her phytoplankton experiments.
If she is not at the computer Diane is either at the microscope, the incubators or working on her phytoplankton experiments.

Diane and Kristen are studying phytoplankton and micro-zooplankton, and it is amazing how these small components of an oceanic ecosystem are vital for the survival of pretty much the entire environment. Diatoms are small single-celled organisms, called phytoplankton. Diane is studying how fast phytoplankton are eaten by micro zooplankton, and how this “grazing” effects phytoplankton populations.

It is a long process to measure water and extract chlorophyll, Kristen is up for the challenge.
It is a long process to measure water and extract chlorophyll, Kristen is up for the challenge.

Let’s try a visual

Phytoplankton = the microscopic “plants” of the ocean. These organisms photosynthesize and drift with the current. Although some phytoplankton do have locomotive capabilities they cannot swim again the current.

Diatoms are a type of phytoplankton. Zooplankton = small animals who also move with currents and eat phytoplankton as well as micro-zooplankton.

Now enter Diane and Kristen, they look at phytoplankton to find out what is eating them, predominantly micro-zooplankton, and are even looking at their relationship with zooplankton pee and how it might work as a fertilizer for phytoplankton. What these ladies do is collect samples of sea water once a day. They use a mixture of 20% whole sea water and 80% filtered sea water (which removes most of the algae, copepods and protozoa), and a 100% whole sea water sample.

This is part of the larval stage, nauplius of a copepod.
This is part of the larval stage, nauplius of a copepod.

Kristin then strains both types of water pre and post incubation, and will compare the chlorophyll samples. What Kristin is hoping for is that after 24 hours there will be more chlorophyll in the 20/80 sample indicating greater phytoplankton growth, due in part, to the fact that there are fewer predators (micro-zooplankton) in this water. Micro-zooplankton eat nearly 50-60% of the phytoplankton, which they are fertilizing at the same time. This relationship is fundamental to a healthy oceanic ecosystem; you could even say these micro-zooplankton help sustain the growth if phytoplankton in the ocean.

After the 24 hour incubation, samples are taken for further study back at the lab. One specimen they often see is a heterotrophic dinoflagellate. This guy has no chlorophyll and wants to eat phytoplankton; it is in other words a micro-zooplankton.

This little gem does not photosynthesize and locomotors by the little hair like tenacles.
This little gem does not photosynthesize and locomotors by the little hair like tenacles.

As I look at the pictures Diane has taken, I am transported to a word that is so small that to tell the difference between plant is animal is very difficult.

Isn't this a great looking microzooplankton, can you see how it moves?
Isn’t this a great looking microzooplankton, can you see how it moves?

Quote of the Day: The great sea has sent me adrift, it moves me, it moves me, as the weed in a great river. Earth and the great weather move me, have carried me away and moved my inward parts with joy. Uvavnuk Eskimo Song

FOR MY STUDENTS: What other areas of study can we focus on while using microscopes?