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Amazing Sponge Facts

Priya Johnson
Sea sponges are not plants or coral, but animals attached to the ocean floor. Available in different shapes, colors, and sizes, these sponges are fascinating creatures with intriguing body mechanism. Let's find out more about these underwater faunae.
The word 'sponge' either reminds us of the bathroom sponge, or the little yellow energetic sea sponge: 'Sponge Bob'. However, we seldom think of the wonderful sea sponges adorning the ocean floor. Living sea sponges look nothing like the bath sponges found in our bathrooms.
The ones available commercially are only six species, from the thousands of sponge species existing today. There are over 5000 species of sea sponges, and every year one new species is added to the list.
Our understanding of sponges is very limited. What we think is a sea sponge lying on the beach, is actually just its skeleton. The skeleton is composed of needle-like splinters called spicules, and a mesh of protein called spongin. A microscopic examination of this skeleton can tell us which kind of sea sponge it is.
Sponges are simple animals, found in seas and oceans across the globe. Although a large portion of the population is found in sea water, about 150-200 species of sponges are found dwelling in freshwater as well. These multicellular organisms can be found at a variety of depths underwater.
While most of them prefer shallow depths, some prefer the deep. Let's find out more about these mesmerizing and intriguing creatures of the sea!

Key Facts About Sponges

How comes sponges are animals?

✦ Surprised! Well, it's true, sponges are not plants! In fact, it's not even part of a coral reef. It is a multicellular animal classified under the phylum Porifera. Until 1765, they were presumed to be plants. 
✦ Sea sponges are classified as animals, however, lack a brain, central nervous system, digestive system, and also a cardiovascular system. They lack the presence of organs, instead have specialized cells to carry out all essential processes.
✦ So if sponges lack a digestive system, how do they get their food digested and excreted? Well, sponges have scores of pores on their surface, called ostia, through which water containing food and oxygen flows throughout the body. The constant flow of water running through their bodies provides the necessary nutrition.
This mechanism of feeding is termed as filter feeding. The waste is also excreted into the continuously flowing water.
✦ Sponges also exhibit the presence of simple cells that mimic the action of muscle cells. These cells help regulate the flow of water throughout their bodies, by contraction and relaxation movements. 

✦ Sponges have hollow bodies to maximize the efficiency of water flow through their body.

Sponges come in different colors, sizes, and shapes...

✦ Sponges come in various colors, sizes, and shapes. Each sponge variety has a different shape and color. They grow in strange shapes and sizes, with some reaching gigantic proportions as well. The demosponge variety is the largest sponge variety, whose species measure about 1 meter wide.
✦ Their shapes vary from tube, cup, barrel, cone, crust, fan, tubes, etc. In fact, the barrel sponges can grow big enough to even hold an adult. The shape of a sponge is held by a gelatinous matrix of mesohyl tissues, and the calcium carbonate spicules that act like the skeleton.
✦ Sea sponges attached to the ocean floors are really colorful and endearing in appearance. The colors range from bright orange, yellow, red to even duller shades of gray, brown, etc. However, they appear dark underwater, due to presence of a dark membrane cover, whose function is protecting the inner soft skeleton of the sponge.
✦ Sponges are found attached to the ocean floor. They attach themselves permanently to solid substrates, such as corals, rocks, etc. so they do not drift around underwater. They may be found growing on rocks like moss, or may be found freestanding.

How do sponges defend themselves?

✦ Sponges can be attacked by predators or even other sponges near them. So to protect themselves, sponges release toxins into the surrounding water and outside their bodies. This also prevents the cells of other sponges from growing. It is because of these toxins that people handling sponges develop rashes after contact.

How do sponges reproduce?

✦ Sea sponges have both sexes in the same sponge (hermaphrodite), however, they produce only one type of gamete per span. This means some sponges act as the male and some as the female, even though they are capable of playing either role.
✦ Sponges reproduce sexually by releasing a sperm into the water, which is then caught by the neighboring sponges. The sperm fertilizes the egg internally and develops into a minuscule larvae that gets released into the water. The released larva goes and attaches itself to the ocean floor and develops into another sponge.
✦ Sponges can also regenerate from a broken portion. When a part of a sponge breaks off, the broken part will form a new sponge, thereby forming another way of reproduction called budding. This power to regenerate is simply remarkable and helps keep the sponge population in control.

Commercial Uses

✦ Due to the soft texture, grass and wool sponges are used to make bathing sponges. Similarly, there are 4 other species that are also used for bath sponges. The yellow sponges with their rough texture, are perfect for exfoliation.
✦ Having said this, one cannot take a sea sponge from the ocean and use it. Sponge fishermen macerate the sponges collected from the water by squeezing it in buckets of water. They then have the elastic skeleton decalcified, rinsed and bleached.
✦ Sea sponges are also used in the medical field, where surgeons use sponges during surgical procedures. After all, sponges have wonderful absorbent qualities.
✦ Moreover, pharmaceutical companies are conducting several studies based on certain compounds found in sea sponges. Researchers believe that some of these compounds can help prepare antiviral medication to treat conditions like tuberculosis, malaria, and cancer.
Since sponges can be rough and abrasive for some with sensitive skin, one should always check with their health care provider, before using sea sponges on their bodies. People handling sea sponges need to be careful as the toxins released, can cause skin rash.
You could even use sponges to paint. The next time you pick up a sponge for cosmetic purposes, painting, or cleaning, remember these how awesome these sponges are!