What are jellyfish?

It was another great weekend on the beach for my family and everyone had new and exciting Beach Chair Scientist questions. The best part about being a Beach Chair Scientist is clarifying misconceptions, so I am going to start with the question that seemed to garner the most discussion this weekend “What are jellyfish?”.

Jellyfish, contrary to their popular common name, are not fish at all! As a matter of fact, neither are starfish. Popular nicknames to avoid this misconception can be to call them jellies or seastars.

Jellies are basically giant plankton. Plankton is anything (living) that is free-floating. It can be a plant (known as phytoplankton) or an animal (known as zooplankton). Jellies are zooplankton. Floating is easy for them. They are over 90% percent water. People are approximately 70% water.  Jellies are in the family Cnidaria (the c is silent). Also in this group are sea anemones and coral.

What do jellies, sea anemones, and coral all have in common?

1. One giant cavity for all digestion
2. Stinging cells (known as nemotacysts)
3. Tentacles
4. Radial symmetry (no matter how you slice it, you will have 2 halves)

Jellies are essentially a giant mouth with intestines surrounded by a skeleton. They have a nerve-net surrounding their transparent skeleton. The nerve-net in some species extends towards the tentacles. Not all jellies have painful toxins in their tentacles.

What do you do if you are infected with a toxin tentacle?

1. Wash with soap and water
2. Apply alcohol, or meat tenderizer and Vaseline
3. Apply ice and contact a doctor

Image (c) pdphoto.org

Do you have another great question? Email info@beachchairscientist.com and just let me know.

Is seaweed really a “weed”?

Actually seaweed is a term given too many different types of marine plants that grow in the ocean and none of them are weeds, in the sense that we would try to get rid up them with a weed killer.

The basic scientific term would really be algae. Algae (Red, brown, or green) are a very large single celled phytoplankton.

Phytoplankton in the world’s oceans is extremely important due to their immense numbers.
Did you know there is more phytoplankton producing oxygen and absorbing the carbon dioxide than there are trees on the land?

Do you have another great question? Check out www.beachchairscientist.com and enter your request!

The First Beach Chair Scientist post is about my favorite animal – The Atlantic Horseshoe Crab

Some might say that the horseshoe crab is quite possibly the scariest looking creature along the shoreline. However, I disagree. There’s actually a sweetheart of an animal underneath that tough, pointy, chitin exoskeleton. I am certain that the horseshoe crab has survived since before the time of the dinosaurs due to its ability to adapt and take in stride all conditions (Darwin’s theory of ‘only the strong survive’ should more aptly be taken as ‘the most adaptable species will prevail‘).

The shells that you may see washed up along the coast line are probably molts. Horseshoe crabs have to shed their exoskeleton just like crustaceans. They grow on average a quarter of their size each time they shed. Females grow to be approximately two feet across and males and a bit smaller (which helps for reproductive reasons).

Another reason that the horseshoe crab is a lot less intimidating than one might think is that the pointy ‘tail’ (telson) is not going to sting you at all. It is what helps the animal turn itself over when the ocean currents flip it a bit. For ten months out of the year horseshoe crabs live in the depths of the ocean floor. They are most often seen coming to the shore in May and June.

Image (c) FreeFoto.com

Please visit the Limulus Love page for more information about the Atlantic horseshoe crab.