Wednesday, June 2, 2010

Packing for Moorea: Measuring the Wind

To figure out how hermit crabs use their 'noses' (antennules) to find food, you have to know two things: 1) how hermit crabs actually sniff (we know this already), and 2) what sort of environment they are sniffing in.

Imagine two kinds of environments. Let's say they are in windy, open field and in the woods. What is different about these two environments? The field is windier, scientists would say the wind velocity, or speed, is greater. It is also more 'blustery' in the field, wind is whipping around you in lots of different directions. Scientist call this turbulence, and it describes how mixed up the air is. The woods are less windy because the trees filter all the wind with their leaves and trunks. This makes the wind velocities slower and the wind less turbulent.

Now, imagine you are trying to sniff something out in the field and then in the woods. How could you figure out where the smell was coming from in each environment? Do you think it would be harder to follow a smell out in the open field or in the woods? Would you behave differently following a scent in the field and in the woods?

Knowing how much turbulence and velocity wind an environment has is important when we are trying to figure out what hermit crabs are doing to find food. So, I have to measure how fast and turbulent the wind is where the hermit crabs live. I can do this with an anemometer, which measures wind velocity. If I take a lot of measurements at different heights above the ground, I can calculate how turbulent the wind is.

Above is a picture of where I collect hermit crabs. You can see two different environments. One is the beach, which is pretty open like a field. The other is in the forest right beside the beach, and the trees filter out the wind. Since hermit crabs live both in the forest and on the beach, I am going to take measurements from both sites and see how they are different from each other. Then I will put a piece of food out for them to find, and videotape how crabs find the food while the wind is blowing.

Here is a video describing the different parts of the anemometer and how it works. What other things do you think I should measure while I'm in Moorea?

And here is a video of us going out into "the field" (Briones Regional Park) to test everything out and make sure it all works before I go to Moorea.

Next stop, Moorea!

1 comment:

  1. I'm impressed Matt knew how to help you set up the anemometer. I would have been sitting in the grass watching you do it. haha.
    ps I'm glad you shared that you smelled poop at the beginning. ;)