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A guide to freshwater sponge!!
Marine life has always been a mysterious world of fantasies since our childhood days. The silent, sleeky creatures of the deep waters on the sea bed always intrigue scientists worldwide to know them better, discover them, and find their potential benefits that humankind can reap.
If we look at the taxonomic hierarchy of the animals, we can find that the sponges conquered the title of most primitive animal till discovered. They are invertebrates, do not have even tissue, and are known as Parazoa.
Let us have a glance over the article to know the characteristics of freshwater sponges and discover their 12 amazing facts-
12 Interesting Facts about Freshwater Sponge
1. Sponges Have Only the Cellular Level of Organization
Generally, based on the group of organization, organisms are classified into:
- Cellular Level
- Tissue level
- Organ and organ system level
As sponges are the most primitive organisms, they have cellular-level organization. Specialized cells perform all the necessary functions like digestion, excretion, and reproduction.
2. Sponges Bear Several Specialized Cells
As they have a cellular level of organization, their cells get specialized to perform certain functions:
- Trophocytes provide food to developing cells and are also called nurse cells.
- Collencytes secrete fibers that form a net in their body layer mesenchyma.
- Gland cells secrete mucous and other digestive juices.
- Germ cells mature to form sperm and ovum.
- Phagocytes engulf food, waste, damaged tissue, and other things.
3. Freshwater Sponge Is the Indicator of the Quality of Water
Sponges belong to the phylum Porifera, in which, among all the families, only one family Spongillidae, dwells in freshwater while most others are marine sponges. Freshwater sponges attach to a substratum like rocks in clean lakes, rivers, and streams.
They are found in depths ranging from the shallow inter-tidal zone to the deep sea beds. Since they are sensitive to pollutants in water, their presence indicates the quality of water. Thus, the habitat of a freshwater sponge means good quality water.
4. Freshwater Sponges Are Master Filter Feeders
Mostly the freshwater sponges are filter feeders. They strain suspended tiny organisms like zooplankton and phytoplankton and consume them as food.
They pass the water over their specialized filtered structure, where all the tiny microscopic algae, plants, and animals get stuck and eat them.
The water enters through tiny holes all over their body called the Ostia and gets out through a large hole called the osculum. Thus they collect their food from the water by running it again and again through their body cavity.
5. Freshwater Sponges Reproduce Both Sexually and Asexually
As they are quite primitive creatures, they have the developed mechanism to lay eggs or give direct birth. They are primarily hermaphrodite, while others are successively hermaphroditic.
They reproduce by:
- sexual reproduction,
- asexual reproduction, and
- through gemmules.
Gemmules are tiny reproductive structures that are dormant, which facilitates them to survive harsh climatic conditions. When a favorable climate comes, they develop into new sponge colonies.
Asexually, they reproduce primarily by budding, where a part of their body falls and develops into a new sponge.
Sexually, they reproduce by gametes, through egg and sperm, produced from respective organs and after meeting develop into new separate sponges.
6. They Are the Most Asymmetric Creature
Sponges do not have regular shapes or sizes, instead, they appear as benign growing masses in the sea bed. As algae increase on them, their color ranges from different shades of green to light brownish; sometimes, some even appear light yellow.
They are asymmetric, and some may be a few millimeters in size, while others can extend over meters and live as colonies.
7. They Are Blessed with a Siliceous Skeleton
For most freshwater sponges, their skeleton is made up of silica as opposed to most other varieties, where they are made of calcium carbonate.
So, most freshwater sponges are siliceous as their body skeleton comprises silica spicules. Spicules are the e structural component of sponges, and they vary from species to species.
8. Canal System in the Freshwater Sponges Is the Most Advanced One
A canal system consists of interconnected cavities that help respiration, obtaining food, excretion, and reproduction. It can be of three types, leucon, and sycon. For most of the freshwater sponges, the canal system is leucon-type.
It is an advanced canal system in which water enters through the dermal Ostia, moves to the flagellated chambers through incurrent canals, and moves outside through excurrent channels.
9. Freshwater Sponges Come in a Variety of Species
Some of the species of freshwater sponges are:
- Spongilla lacustris
- Ephydatia cooperensis
- Clypeatula cooperensis gen.
- Radiospongilla sceptroides
- Corvospongilla lapidosa
- Dosilia plumosa
- Ephydatia muelleri
- Radiospongilla cerebellata
- Ephydatia meyeni
- Eunapius carteri
(The first word is the genus name, and the second is species). More and more keeps going to be identified. Ephydatia cooperensis is an endemic sponge species found in Western Montana.
Some freshwater sponge species were also identified in the Washington DC area in North America and mentioned in US Forest Service species.
10. Freshwater Sponges Have a Commercial Value Too
Research keeps discovering more and more uses for sponges in our lives. The quality of water has always been a long-term concern, and the presence of freshwater sponges indicates the excellent quality of water. Contact with polluted water can kill them.
- Their beautiful shape, size, and color have always fascinated humankind, and hence they are used as decorative items.
- Several species are also used for cleaning industries and also for cushioning purposes.
- Spongin fibers, spicules extracted from them, are used for painting, bathing, and other purposes.
- Some species produce toxins that are even harmful to man.
- Some species also have pharmaceutical value as they have anti-human or, anti-inflammatory activity.
11. Sponges Play a Crucial Role in Aquatic Ecology
Sponges play a pivotal role in maintaining the coral ecosystem. The silent creature in the sea bed has a lot to do in preserving the biology of the aquatic ecosystem.
- They form a symbiotic relationship with many green algae and bacteria. In this relationship, the presence or absence of sponges also affects other animals and plants.
- They are a part of the food chain. They eat plankton and, in turn, get consumed by other animals like sponge-eating fishes.
- They also contribute to the biogeochemical cycling of nutrients like silicon, nitrogen, and carbon.
- They help in the benthopelagic coupling, which means coupling ecological activity in the water column to that taking place in the sea bed.
- Several groups and institutes like the Montana Natural Heritage Program work with the conservation of sponges in their areas.
- Heavy boat traffic, as it affects aquatic life, also affects the sponges.
- Unauthorized boat docking and pollution in freshwater also harm the sponges.
12. Phylogenetic Relationships- The Most Primitive Animal
In the metazoan phylogeny, Porifera is the first phylum. The two oldest sponges groups are- Hexactinellids and Demosponges. They diverged from the choanoflagellates about 1020 million years ago.
13. Freshwater Sponges Can Be Cultivated Too
New sponges can be cultivated in several methods, mainly in clean, still fresh water like lakes and ponds. Sponge culture is a part of aquaculture and provides a year-round income for the cultivator.
It is quite easy and does not involve much hard work. The regenerative capacity of the sponge is exploited for cultivation purposes. Small parts of the sponge being cut are provided with an adequate environment, including the right temperature and nutrients from where a new sponge population can arise.
Some methods to be mentioned include:
- Floating Raft method this method, a raft is bamboo of bamboo, and tiny pieces of sponges keep hanging from which new sponges arise.
- Disc Method- Through this method, a disc of a particular size made of cement is being cut and kept at a fixed depth inside water. Small pieces of sponge are held there from which new species develop.
14. Freshwater Sponges Can Live upto 200 Years
Usually, in the temperate region, the freshwater sponges live for a few years. However, some deep-ocean or tropical species may live for as long as 200 years or even more.
Some Last Words
Currently, finding freshwater remains the most challenging task. Most freshwater sources are polluted with toxic compounds that prove fatal for aquatic life with increasing pollution. Many species get extinct much before they are discovered and known. With the reduction in the water population, more and more freshwater sponges may start to appear.
Although the sponges are the most silent and primitive creatures we should not undermine their importance and value in our ecological system. We must conserve them as we, also a part of Mother Nature, follow the eternal hymn to live and let live.
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I hope you found the facts on freshwater sponges interesting enough. If you have any questions, feel free to contact us.
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Frequently Asked Questions
1. How many sponges are freshwater?
There are around 150 species of freshwater sponges found in lakes, ponds, and water streams.
2. Do freshwater sponges eat?
Yes! They are a part of the food chain. They are filter feeders and eat plankton, viruses, and bacteria.
3. Why are Porifera called sponges?
Porifera means pore-bearing. Sponges are named after small holes on their bodies which represent pores.
4. Do sponges have organs?
No. Sponges don’t have any internal organs but their specialized cells can function in digestion, excretion, and reproduction.
5. Is a sponge a fungus or an animal?
A sponge is considered to be an aquatic animal.