NOAA Teacher at Sea
Onboard U.S. Coast Guard Vessel Healy
July 1 – 30, 2008
Mission: Bering Sea Ecosystem Survey
Geographic Region: Bering Sea, Alaska
Date: July 18, 2008
So there I was feeling really confident on my introductory journal on krill only to realize I really knew nothing at all. Tonight I sat down with Alexei Pinchuk and Rachel Pleuthner, wow, I am so impressed with the depth of their knowledge and expertise. But now I am tasked with trying to open a small window into this vital part of an oceanic food web.You have met Kirby the krill, but we should have called him Sam the spud, for the krill is the potato of this ecosystem. These little guys fuel this bionetwork like there is no tomorrow. But I am getting away from myself. Let’s get back to the krill science going on aboard the HEALY.
The krill team is currently involved with at least three different experiments, and I will try to describe each, but please cut me some slack, this is a field of discovery I am just beginning to learn and as Rachel was explaining I would find myself not writing notes and becoming totally engrossed with the discussion.
Experiment # 1: Krill grazing /aging
We already touched on this aspect of the krill work, looking at the diet of krill over a 24 hour period. But what we didn’t hit on was what is then done with the krill after they have grazed. Tracy will measure and key out the specific species of each animal and then pass the krill off to Rachel…Rachel in turn will remove the eyes. Yes, this delicate operation will give a general idea on the age of the krill. Basically our team will extract from the eyes a substance called lipofusion which can then be used to age the krill.
Did that make sense? Because now Alexei comes into the picture, he is trying to actually raise krill in a controlled setting, providing valuable baseline data on how old a krill is to the day. When lipofusion is removed from wild krill it gives a general idea on aging, but is not completely quantitative, thus the two experiments work together to finding the exact age of a krill.
Experiment #2: Starvation is another component to the work the krill grazers are completing. At the start of the voyage, 14 days ago, approximately 20 krill were placed in filtered sea water. What that means is that the krill salad bar was empty. Then, once a week a sample has been removed to look at the lipids. The type of lipids in a krill will tell the scientists what they had been eating, and how the components are breaking down in their systems.
A krill can live up to three years, with their specific ecosystem and species as two variables that can affect longevity, but what about the source and timing of food. If the juvenile (nauplii – first stage in krill development) hatch when there is no food and they need food well, you can guess what will happen. There are though some krill who store their lipids all winter so that they pass this nutrient source to their young, really fat babies, who are in turn not as dependant on the first zooplankton bloom.
Ughhhhhhh I really do have a beginning understanding to this krill research, but explaining it has been a challenge. I still have more to share, but need to do a bit more of my own fact finding and research.
Photo of the day:
Quote of the Day: For whatever we lose (like a you or a me), It’s always our self we find in the sea. -E.E. Cummings
FOR MY STUDENTS: Are there any microscopic organisms that might live in our aquatic ecosystems that you think we could study?