|Our whole class :)|
Friday, May 23, 2014
To monitor the sand crabs, we used a large tube to scoop up sand were they might be burrowing (the white thing Charlottes holding), then we put the sand into a sieve, and poured water into the sieve to sort the sand form the rocks/sand crabs (Jesse and Emily). Our group did not find and sand crabs, but other groups did.
|In the picture from left to right: Jesse, Charlotte, Emily, Olivia and Jasmine.|
In the back round from left to right: Chimi, Max, Sam, Aschabel , Liam, Knoa and Anika,
nora and some other people. :)
Our class only saw a couple of sand crabs but we did find this one. Our science teacher pulled back the telson and we saw all the tiny orange eggs! The Telson is the part of the shell underneath the sand crab that covers its eggs.
|A female sand crab with eggs!|
The Sandy Beach is located along the coast of California. It has a very rich ecosystem with many different organisms. For many organisms it is a very difficult place to live. There is almost nothing to attach onto and they have to deal with crashing waves, changing tides and and a beach that changes with the season. Many of the animals live in the swash zone. The swash zone is the area in the sand where the waves crash.
One of the very important species living in the swash zone is the Pacific Mole Crab, also known as the sand crab. It is a small crab-like organism and it is grey or sand coloured. They are usually found in large quantities in spring and fall. In the winter they are carried offshore into sandbars. They then return the following spring with the sand which rides with the tide. Sand crabs are one of the most important species in this ecosystem because they help monitor the health of the ecosystem.
|Our 7th grade class monitoring sand crabs at Muir Beach|