Sponges are among the most fascinating creatures of the sea. For a long time, there was a debate about whether or not they should be classified as an animal at all, with many researchers believing they have more plant-like qualities. The fact remains that the sponge is one of the most basic form of multicellular life on Earth, and it is very similar to plants. Nevertheless, these sea-dwelling animals have many impressive secrets to share that has astounded the scientists who have studied them throughout the years.
Sponges are tiny multicellular creatures that usually live on the bottom of the sea, in places such as coral reef formations, or in some cases, even in the deep ocean. They survive basically by anchoring themselves to solid, hard ground and using the pores that their bodies are covered in to filter out the water around them and retain precious nutrients, substances and minerals needed for their survival. Sponges don’t actually have nervous or circulatory systems, and they rely on a few basic systems to channel water through their pores, capture food and use the energy stored in food particles as nourishment.
First of all, it’s important to mention that sponges don’t actually have separate respiratory or digestive systems. They simply feed through their pores, which capture food and send it along through various canals and cavities to be broken down and used throughout the body. The pores (ostia) of the sponge themselves are extremely small – only 50 micrometers in diameter – and the sponges use them to lead food particles through a series of interior canals and chambers where collar cells break down the food and amebocytes distribute the acquired food to other cells within the sponge to complete the feeding process. Particles larger than 50 micrometers will not fit inside the ostia and are instead broken down and consumed by pinacocytes – the exterior flat cells present around the outermost layers of the sponge.
Sponges are capable of taking water in and ejecting it at an extremely impressive rate each day. They have basically evolved a system that allows them to use their simple flagella and pores to take water in at the bottom, then ejecting it through the osculum (a small orifice at the top). By varying the beat of the flagella and controlling the extent to which its spores are open, the common sea sponge is capable of efficiently filtering water through more than 80,000 tiny canals at a rate of 6 cm per minute. At this rate, it is able to filter an amount of water about 100,000 times its own size in as little as 24 hours.
Sea sponges generally live in oceans and seas, although there are some exceptions. Some sponge species also dwell in fresh water regions and are quite adaptable. As for climate, most sponges do fairly well in temperate climates, while others are able to thrive in tropical climates. Generally, however, sponges are highly resilient and can survive virtually anywhere on the globe where there’s water, their remarkable ability to anchor themselves to solid objects and feed on even the smallest particles of food making them capable of dwelling in a wide range of different oceanic habitats.