Do I hear bongo drums? No, it is Dr. John Nelson, biologist, going to work after several hours of sleep. He works every station so he is up most of the time.
...ready for action
He is collecting zooplankton in a large piece of equipment that looks like a set of bongo drums with nets attached to it. The nets have very small holes (150 micrometers) that allow the seawater and most of the phytoplankton (small, drifting microscopic plants) to flow through but not the zooplankton.
A zooplankton under a microscope, 3.5 mm long.
Zooplankton, are small animals that can drift in the water's currents although they have some means of locomotion They often move vertically in the water as they rise up near the surface to eat at night and fall back down during the day, away from predators. For food, zooplankton eat algae in the water. Copepods are a major type of zooplankton the live in the Bering Sea. Copepods are a favorite of Dr. John.
The nets are tucked into the metal drums.
Dr. John is a one-man show as he must carry the bongo nets outside, attach the collectors to the end of the net, and then attach the weights to hold the nets downA cable line attached to a winch lifts the bongo net into the air. The weight at the bottom will keep the net pulled out while in the water. The bongo net is lowered into the water.
In the cold, everything freezes up including the cable connections.
The cod ends are the cups with mesh at the end. The cups hold the plankton in while the water escapes out the mesh covered holes
When the line reaches five meters from the bottom, the bongo net is raised up. As it comes up, zooplankton get trapped in the net and travel down into the cog ends, small cups, at the end on the nets. The cog ends are removed and the zooplankton is collected and preserved for future counting and identifying. Dr. John is collecting zooplankton at an early stage of the algae's spring bloom. As spring progresses, the number of zooplankton will increase as the sunlight becomes stronger and their food, algae, begins to flourish.
Plankton nets overboard.
Bongo Nets dip...into the water
On this trip, Dr. John is primarily collecting samples. The majority of the work will take place after he is off the ship when a zooplankton taxonomist, someone who is an expert at identifying zooplankton from looking at them through a microscope, will examine the zooplankton in detail. The results from this analysis will be combined with the work of the other scientists on the ship to help understand how the Bering Sea ecosystem as a whole develops into the early spring bloom period.
As the climate changes, how will this affect the growth of the zooplankton John is studying? Dr. John's work is the start of a multi-year test. If all goes as planned, next year, he will be collecting samples to compare to the zooplankton collected this year. Zooplankton are very sensitive to changes. If Dr. John and other scientists observe changes in the zooplankton, then they may be able the predict changes that will be seen in other organisms in the Bering Sea ecosystem.
Kites in the air.