Big Mouths, Glowing Spines - Video Transcript
BIG RAPA Tow Net – Station 1 Video Script
One way for microbial oceanographers to collect and view the microorganisms living in the surface ocean is to drag a net with a collection cup attached at the end. Effectively this concentrates the sample of microorganisms.
Ricardo Letelier and Angel White, scientists from Oregon State University, employ this technique.
So this is one of the oldest tools we have had in biological oceanography. It’s basically a net. It’s the same type of principal you have to catch fish. It has mesh, two different sizes, a large size in the cone and a smaller one in this bucket that will trap everything. So all the organisms that are larger than the size of the mesh will get trapped. They will be washed into this bucket. We will deploy it for around 10 to 15 minutes, until we consider that we have enough material. And then we will bring it back on deck and look at it under a microscope to see what we find here.
And essentially now the step is to look at all this biomass under a microscope and see what’s there. We’re on this cruise mostly to look at photosynthetic microbes. They use carbon-dioxide and light to make plant biomass. Interestingly, they’re not the only things in the ocean. There are a lot of things that have developed mechanisms and make a living on eating these different plants. Some have hard parts. Some have soft parts. Some have spines. The zooplankton, the grazers, you’ll see some pictures of those. There is phenomenal diversity. You’ve got organisms with long red antenna. With huge mouth, arroworms, it has a mouth twice the size of its body. Really dizzying array of movement and motion under the scope.
Basically we’re going to look at this biomass and get an idea of what types of phytoplankton, what types of plants are in the surface ocean and what types of grazers or zooplankton are in the surface ocean.
So we’re in an upwelling regime right now. What that means is deep cold nutrient-rich water is being brought to the surface. So this is a very productive region. In this region we get phytoplankton called dinoflagellates. They are armored phytoplankton. They’ve got hard parts. They are encased in hard parts, but they’re still plants. They still use light and CO2 to make phytoplankton biomass. In these samples we are seeing tons and tons of dinoflagellates, these armored phytoplankton. And in association with that, we’re seeing the organisms that make a living eating them. We’re seeing copopods. So lots of copopods. They’ve got these round bodies, long antenna, these very lipid-rich bodies. They store these wax esters, fats. That’s essentially the food web we’re seeing here. Lots of copopods, lots of dinoflagellates. It’s going to shift incredibly once we get out to the blue water. We’ll see a totally different microbial community structure. Right now it’s fun to interestingly to look at what’s here. It’s really fun to see.
What about the microorganisms that didn’t get trapped in the net? Stay tuned to learn about them.