I was finally able to get back out to the beach and work on my project. I'm trying to determine if mole crabs prefer a certain sediment size/type for their habitat or if it doesn't affect them at all. This time I traveled south to Frank Rendon Park in Daytona Beach Shores. This is a part of the county that allows driving on the beach. I noticed right away that the sand on this beach was very hard. I walked about a quarter of a mile south from the beach ramp pausing occasionally to dig for mole crabs. I did not find a single mole crab. I did however find tons of washed up jellyfish and a few
egg cases, or devil's purses. Egg cases surround the fertilized eggs of sharks or skates.
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| Jellyfish |
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| Egg Case |
I decided to to take a sample of the sediment anyway to compare to the sediment where I did find mole crabs. Just looking at the samples I can see a difference between the two. One sample is full of broken shells and has a reddish-brown color to it. The other sample is your typically looking sand with no color or shells. I'm going to use the sieves in the lab to record the sediment size of each sample. I also want to record how much of the sample is
biogenic, comes from organisms, and how much is
lithogenic, comes from land.
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| Sediment Samples |
I find those egg cases fascinating; so glad I got to see one up close at the Marine Science Center. Did you check if the egg case was empty?
ReplyDeleteThe ones we saw at the Marine Science center were the first I ever saw. Then I found 3 at the beach! They were all empty.
DeleteIn class I had asked you if these mole crabs occur only on North American shores or also, e.g. in Europe. If these mole crabs were to ever make it to European shores, would they be harmful or useful to the environment?
ReplyDeleteI will look into this!
DeleteDo you know what species of jellyfish that might be? I also saw a few during my field work today, I am wondering if it is a breeding or migrating season for them.
ReplyDeleteThey are called Cannonball jellyfish!
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