Sponges of Key West
When Key West scuba diving there are a lot of sights to be seen. This includes quite a bit of marine wildlife, from flashy tropical fish to the more quiet animals. While most people have seen dried sponges sold in stores, it is a novel sight for many to see them living and thriving in their natural habitat. With a variety of colors and sizes, these understated marine animals are a sight worth seeing.
Sponges have porous bodies that allows water to flow through them. Since they cannot move quickly or hunt in the traditional sense, this is how they obtain their food. They filter it out of the water as it passes through their body. Waste is removed in the same manner. They can open or close their intake pores to control how fast water is flowing through them, or to stop the flow if they need to work sand or other blockages out of those channels.
Their actual shape can vary greatly, and is held together by mesohyl, a jelly-like material that also characterizes jellyfish. Their lifespan varies greatly as well between different species of sponge. While some only live a few weeks, others can live decades or even a couple hundred years. It is possible that there are even species which have survived thousands of years. There are three main groups of sponges, but the most numerous group is demosponges, which is also the group that grows to be physically largest. This group can be very colorful, making them a beautiful find on any dive.
Sponge Eating Habits
As already mentioned, sponges do not eat in the normal sense of the word but filter food out of the water that flows through them. There are a few species of carnivorous sponges, but they are in the minority. These species have added crustaceans such as shrimp to their diet. Though their method of hunting is not entirely understood, there is at least one cave dwelling carnivorous specie that wraps its prey in threads to capture it.
Sponges are found all over the world in many varied aquatic environments. Though there are more saltwater sponges, freshwater species do exist as well. Likewise, they are found everywhere from the deep ocean to more shallow seabeds.
Though they do use the movement of the water to help them filter water, they also stay away from water that is too silty or stirred up, as it can cause their pores to become too clogged. They also generally require a hard surface to settle down and attach to, though there are species of sponge that are capable of settling on soft surfaces as well. Juvenile sponges are free floating before they find their preferred spot to settle on. Even then, they are capable of movement, but it is infinitesimally slow. Though there are numerically fewer sponges in tropical waters, the ones that are found there are more varied and diverse in their appearances.