Underwater Plants

Today, we’ll be discussing the ‘plants’ under the sea. Or, sea sponges and coral.

Sea Sponges

Sea sponges have tiny little openings all over. These are used to catch their food. Their food is smaller then even their microscopic cells. Their diet consists mainly of plankton, choanocytes, and archaeocytes. These tiny creatures drift through the water, aimlessly riding its current. When the undersea current flows into the sea sponge, the microscopic plants and animals become the filter feeder's next meal.

Sea sponges also flow water through their pores, with or without the foods they eat. More on this later.

Sea sponges are what are called ‘simple animals.’ Sponges have no organs or tissues. Instead, they have three layers of cells with different jobs.

The outer layer is the one with the pores. These pores are very small and only let the sponge’s food (mentioned above) enter. The rest of the sponge’s outer layer is quite hard. This is the protective covering of the sponge, and keeps it safe from other animals that might want to eat it.

The next layer, the one in the middle, also plays an important part in the eating process. This jelly-like layer is ridden with many channels. The food and water that enters through the pores of the outer layer are moved through these channels by the middle layer’s cells.

The third and final layer’s (or the inner layer’s) cells take the food and oxygen from the water and build a hard, sharp skeleton to support the sponge. These structures are called spicules.

Now that we have sponges covered, it’s time to talk about coral.

Coral

First of all, coral is made up of tiny little animals called polyps. Secondly, their are two different kinds of corals; hard and soft corals. First, we’ll talk about hard corals.

Hard

Hard corals  are made up of polyps (as mentioned above). Polyps are microscopic organisms that grow and die amongst one another. This growth ad death process gradually creates a large and hard mass of polyp skeletons. True to their names, the hard corals form a protective exoskeleton.

Now, for all corals (for both hard and soft verities), algae is vital. But it plays a particularly important role in hard corals.

Algae doesn’t just give corals their beautiful, diverse shades colors, but it helps them with food. Algaes produce food for hard corals in exchange for a place to live (safe inside of the hard exoskeleton). But this awesome allegiance isn’t the only way hard corals get their food.

At night, hard corals reach out their tentacles to catch tiny organisms called zooplankton that drift through the water. But during the day, the vulnerable tentacles retreat  to their hard homes, the coral, so that they are safe from predators.

Soft

Soft corals are also made of polyps, but these polyps are solely alive. This means that there are no exoskeletons on soft corals. Soft corals can also make a beautiful display when, in the underwater current, they gently and gracefully wave about.

Thanks for reading!
-KittyLover8
© 2013