Ms. Callaghan’s Classroom
Jil Callaghan is a 6th grade science teacher at Houck Middle School in Salem, Oregon. She is posting blogs for her students while aboard the Research Vessel Sikuliaq as part of a teacher at sea program through Oregon State University.
Getting to the Bottom of What’s Happening in the Arctic Ocean
Yesterday we did our first deployment of a piece of science equipment that is called a multi-corer. I got to help out and had fun! First you have to wear what’s called a big orange “float coat” that will help you stay afloat if you go overboard, but it also helps keep you warm 🙂 You also have to put on a hard hat. In the photo above, I got to help pull the multi-corer back towards the ship – we use hooks to attach ropes to loops on the multi-corer.
What’s a multi-corer?
A multi-core is a piece of scientific equipment that we send down to the bottom of the ocean where it drives 4 tubes into the sediment layers down there. As we lift it up, it snaps shut, giving us tubes with “cores” of the sediment (mud) at the bottom of the sea. It also has a CTD tube to collect water, measure temperature, and salinity; an altimeter to measure pressure and depth; as well as a very expensive curved lens for the camera; and 2 lasers.
What does the mud tell us?
Dr. Miguel Goñi from OSU is looking for evidence of animals and plants that have died and fallen to the ocean floor. Looking at what is on the ocean floor gives us an idea of what has been growing and living in the water up above. Based on the rate at which sediment falls to the bottom, and the depth of the samples we collect (some of that mud down there is very thick, like clay, and hard to push through), our samples can tell us what’s been happening for the last 200 years!
One thing that we can see evidence of is phytoplankton blooms – where the ocean currents bring nutrients (food) and the phytoplankton (microscopic marine plants) suddenly grow like crazy – called a “bloom”. After they use up the nutrients they die, and some will fall down all the way to the bottom of the ocean (others will be eaten before they reach the bottom). This layer of dead phytoplankton as evidence of blooms is one of the things that Dr. Goñi is looking for in his core samples.
The above illustration shows various benthic animals: 1. common whelk, 2. blue mussel, 3. Neptune whelk, 4. periwinkle, 5. Yoldia hyperborea, 6. sand gaper, 7. limpet, 8. scallop, 9. chiton, 10. common starfish, 11. green sea urchin, 12. brittlestar, 13. ragworm, 14. pectinaria worm, 15. scaleworm, 16. skeleton shrimp, 17. isopod, 18. barnacle, 19. benthic amphipod.
See Ms. Callaghan’s other posts here.