Human Impact on SpongesHuman impacts on the ocean have impacted sponge habitats. Humans have increased the carbon dioxide in the air, and as a result are acidifying the ocean. Top: Comparison of sponges overrunning coral in natural and overfished locations.
Sponges are critical components of the ecosystems of coral reefs, where they provide shelter for a variety of organisms including shrimp, crabs, and algae. They are also a source of food for many sponge-eating fish species. Many sponge species form large colonies or aggregates of individual organisms.
Coral reefs are made up of many millions of cnidarians and is the home to terrific biodiversity as well as serving as breeding grounds for many species of commercially important fish. Sea jellies are important predators, part of the food web, in the open ocean. They serve as food for many species as well.
Although few representatives from sponges are approved as drugs, hundreds of new compounds with interesting pharmacological activities are discovered from sponges every year. Several sponge-derived compounds are already in clinical trials as agents against cancer, microbial infections, inflammation and other diseases.
What are sponges? Called Porifera because they are porous or 'pore bearing', sponges are animals designed around a unique body plan of canals and chambers through which they pump water to extract food. There are an estimated 15,000 sponge species living today, but only about half of them have been described and named.
Sponges are classified as animals, albeit primitive ones. They belong to the phylum Porifera. Like other animals, they absorb organic carbon rather than fixing it from inorganic sources such as carbon dioxide. Their cells do not have cell walls (plants do).
The Demospongiae is the largest class and all species of some commercial value belong to this group. The commercial sponge is the macerated and dried skeleton of a sponge. The commercial value of the sponges comes from their great internal surface, thus they can absorb water up to 20 – 35 times their weight.
Their bodies lack true tissues but are composed of many different cell types each with special functions. Also within this middle layer, sponge cells roam throughout the body; transporting food, oxygen, waste products, building organic skeletons, secreting inorganic skeletons, or forming feeding chambers.
Most sponges are hermaphrodites (function as both sexes simultaneously), although sponges have no gonads (reproductive organs).
Many organisms do not have true brains, but rather a "nerve net" of neurons scattered through their bodies. However, sponges do not even have that. This suggests that complex brains were in place as early as 520 million years ago. But they may not have stayed.
Sea sponges can only survive in saltwater, so if you put them in freshwater, they will quickly die. They are also very sensitive to air and do not like to be taken out of the water because their pores get filled with air. If too many of their pores are filled with air, they will die.
Sponges reproduce both asexually and sexually. Asexual reproduction occurs by budding. Sponges may also reproduce asexually. Sperm are released into the surrounding water through the osculum.
Natural sponges are used by car, boat and aircraft enthusiasts to safely wash vehicle finishes, interiors and clean wheels and tires. Baby bathing is one of the most popular uses of natural sponges, as they are extremely soft and gentle on a baby's skin and produce a rich soothing lather.
And yet despite not having a nervous system, sponges are able to respond to their environment by changing the canal sizes in their filter-feeding system, in an action called the “inflation-contraction response.” It's basically akin to what we do when we sneeze.
In order obtain food, sponges pass water through their bodies in a process known as filter-feeding. Water is drawn into the sponge through tiny holes called incurrent pores. As it passes through the channels and chambers inside the sponge, bacteria and tiny particles are taken up from the water as food.
No, sponges are not on the endangered species list. However there are threats to their habitat in some areas, including benthic trawl fishing and coastal development, which causes terrigenous sedimentation.
Coelenterates as a whole are of little economic importance. Seldom used as food by man, they are eagerly devoured by certain fishes and by invertebrates such as the crownof thorns starfish . Certain corals used as ornaments and for the manufacture of jewelry have become rare because of exploitation.
Here are 10 ways to turn a pack of kitchen sponges into an afternoon of fun.
- Give Them a Squeeze. Image courtesy of Pixabay.
- Sponge Paint a Masterpiece.
- Make Water Balls.
- Build a Tower With Quiet Blocks.
- Get Gluing.
- Try Out Some Tangrams.
- Sail Away.
- Play Sponge Tennis.
Some spicules are formed of the mineralized substances calcium carbonate and silica, while others are made of an organic substance called spongin. Spongin skeletons were and are used as scrubbers in bathtubs, though they are fairly expensive. The ubiquitous bathtub accessory called a lufa is NOT a sponge, but a plant.
Sponges are often considered an evolutionary dead end because they are so specialized in pumping water through their bodies that it is considered impossible to be modified into anything else. Although sessile, sponges can change their shape and grow towards water rich food.
