Mermaid McKenna

Time for another !! Today's topic is bivalves. These are two-shelled creatures, from giant clams to beautiful scallops. Bivalves have gills to breathe and gather food. They are filter feeders. Many bivalves have a foot that they can use to move around and burrow in the sediment. Bivalves can also make their own shells using an organ called the mantle. The mantle secretes calcium carbonate, which is what shells are made of! Bivalves are great for sea life to have around because they filter the water and provide shelter. They are also found virtually everywhere underwater, including on hydrothermal vents!! Hydrothermal vents are an extreme pressure and heat environment, so this is... impressive! And magical :)

Happy Halloween!! 🫧🪸🧜🏼‍♀️🐚

Guess what time it is? Time for another !! 🦈 Did you know that sharks have been around for 455 million years?! That's right, even though sharks don't have bones (they instead have cartilage), they can still fossilize! As sharks age, they deposit calcium salts in their cartilage to strengthen it, and their teeth have enamel. Both calcium salts and enamel preserve quite nicely! Calcium salts are found in bones, so these give shark skeletons a more sturdy structure. That's why shark jaws look like bone! Sharks have a very unique anatomy. For one, they have special electroreceptor organs called the ampullae of Lorenzini. These electroreceptor organs can detect electromagnetic fields in the ocean, as well as temperature shifts. Electromagnetic fields, detected by the shark, are essentially just moving charge. Organisms, such as shark bait, produce electromagnetic fields when their body performs its usual functions, such as sending electricity through its muscles and neurons. Since this is considered moving charge, shark bait produces its own electromagnetic field, which the shark readily detects using its electroreceptor organs, the ampullae of Lorenzini. Despite having the ability to sense prey through electroreceptors, most sharks also have good vision! You wouldn't think they'd need it, but sharks can see well at night and they can see the ocean's colorful display during the day. No wonder they're considered apex predators! There's so much more to know about sharks, thanks to the outstanding research that has been done on them in recent years, but I'll leave you with this for now :) It's crazy to think of the amazing discoveries that can be made when we study the secrets beneath the waves.