Ask a Marine Scientist:

answers to Porifera questions!

Index To Questions

Sponge website information Real and factory sponges Sponge Communication

Sponge reproduction Sponge Life Spans Mystery sponge First sponge genus

Sponge Information - Received from Katie in Hawaii.

Q: I am doing a report on Ocean Sponges, and am having a hard time finding info on the web. Any suggestions? Thanks Katie

A: It seems that you're finding out what many people already know - lots of information is either not easy to find on the Web, or does not yet exist on the Web! A quick visit to a school library might provide you with the information that you seek. In the meantime, there are a couple of sites that have some detailed information on a variety of marine phyla.
The University of California Museum of Paleontology is a good site. If you navigate through it, you'll find information on 4 different classes of sponges: Calcarea, Hexactinellida, Demospongiae and Sclerospongiae. This site also features a page with an excellent diagram of a "typical" sponge.

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Real and factory sponges - Received from Sean in Gilroy, CA.

Q: Hi I'm doing a report on sponges, the differences between them and factory sponges, but I cant seem to find any information on them. Thanks.

A: Sea sponges are animals in the Phylum Porifera. They are relatively simple animals, but are still multicellular, and do things that you would expect animals to do, such as eat, grow, and reproduce. One group of sponges makes a "skeleton" for itself out of a material called "spongin". (Others use calcium carbonate or glass spicules). The material spongin is very soft an pliable. This is why people collected these animals, dried them out, and used their skeletons for bathing. This is still done today, and you can buy a "real" sponge from many bath boutiques. Most commercial sponges today, however, are made from plastics and other artificial materials. For more information on sponges (the animals!), try looking at the OceanLink pages of links to other marine sites.

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Sponge Communication - Received from Micheal Lee in Torrance, CA.

Q: In school, I have the assignment of putting together a report on how sponges communicate, and I can't seem to find any answers. The closest I have gotten is a scientific abstract that is too confusing for me to understand. So can you please tell me how sponges communicate? If not, can you please tell me where I might be able to get this information? Thanks a lot

A: What a great question. It's a pretty obvious question really, but most people don't think that sponges do anything they need to communicate about so they don't come up with it.

The short answer is that for the majority of sponges we don't know how they communicate. There are three groups of sponges. Two of which are cellular, that is are made up of lots of individual cells glued together by collagen and cell adhesion molecules and junctions, as we are. These are the demosponges and calcareous sponges. The third group, the hexactinellids, are syncytial. That means their cells are multinucleate, and in fact they are really really long strings of tissue, strung out like a spiders cobweb over the skeleton) with nuclei that truck around on pathways of microtubules, one of the the structural proteins of the cell that allow other molecules and proteins to move from one spot to another. OK. To communicate quickly i.e. electrically between cells you need to have an aqueous pathway, or a hole
between the cells. First, most cells are excitable themselves. If you stimulate them (poke them or apply current) the current will travel around the cell and activities in the cell will be affected. The membrane, however, acts as a good insulator stopping the current from going beyond. But, in
addition to nerves which are specialized for carrying ions (current=electrical signals), most animals have gap junctions. These act like a sieve for ions and allow a signal to pass from one cell to another.
The thing is that gap junctions haven't been found in sponges at all. They are known from the Cnidaria (jellyfish and anemones) up. So sponges that are cellular technically don't have a way to send a signal rapidly between the cells. But we do know that they can co-ordinate reproduction, as you said,
and some cringe if you touch them, though very slowly. What is likely happening in the first case is chemical communication. A hormone or something is given off by one sponge and picked up though the water it filters all through the body, and so all cells exposed receive the signal to release gametes. This doesn't have to be too quick. In the cringe response it's possible that there could be a mechanical or physical tweaking of one cell to the other, OR more likely there could be a calcium signal, passed
out though normal ion channels from one cell to the other. Calcium is used for slowish signalling in a number of animals (even in our brains by the glial cells) and could be used here, though no one has looked as it's quite a challenge.

Finally, the case of the hexactinellids is quite different. As they are syncytial their cytoplasm is all connected and there are no barriers, like the membrane, to electrical signalling. In fact if you touch a hexactinellid sponge it stops pumping water through the body right away. The response is electrical but is slower than the kind of signal that runs through nerves, mostly because the pathway is really circuitous (windy) and there could be fewer ion channels along the membrane, and likely there are fewer ions travelling in and out of the membrane each time the signal is reboosted as it travels along the sponge, all things that would slow it down. But none the less when something in the water touches a hexactinellid (perhaps a piece of dirt in the incurrent canals) an electrical signal travels through the whole sponge telling it to stop pumping. Why they have syncytial tissues, and why this ability to communicate electrically, a parallel system to nerves, evolved is another really interesting question we know nothing about. Hexactinellids would probably communicate chemically to reproduce like the demosponges, but again NOTHING is known about this at all.

If you want to visualize the structure of a hexactinellid I have a paper in the fall issue of Invertebrate Biology. And if you want to see a blurb on the electrical communication, we have a short communication in Nature, in the spring of 1997 (Leys, S.P. and Mackie, G.O., 1997. Electrical recording from a glass sponge. Nature 387:29-30).

Hope that helps.

Answered by Dr. Sally Leys

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Sponge Reproduction - Received from Jeff and Sue in New Jersey.

Q: Do sponges reproduce by eggs, budding, or both?

A: Sponges reproduce both sexually (with gametes, or egg and sperm) and asexually (without gametes). Sponges are hermaphrodites which means that they are both male and female - they can produce both egg and sperm. The eggs or sperm are released at difference times to enable cross-fertilization with other sponges. After eggs are fertilized, the larva floats about before it settles to the ocean bottom where it will grow into an adult sponge. Sponges also reproduce asexually by the formation of buds or gemmules.

Answered by Adrienne Mason, in consultation with Dr. Andy Spencer.

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Sponge Life Spans - Received from Claudette Bruck in Fort Lauderdale, Florida.

Q: What is the life span of a sponge. Just how long do they live?

A: Some marine sponges live only one year, and others may live many years. Many sponges in temperate regions are usually dormant in the winter, where they lack flagellated chambers and other components of their water canal system. When the temperature increases the sponge redevelops into its functional adult condition. Freshwater sponges also over-winter in either a regressed state or die, releasing gemmules (a type of asexual reproduction, where a sponge releases a packet of essential cells, a gemmule, that can develop into a new sponge). Some sponges species may be considered "immortal", because if you were to take a sponge, blend it up and put the blended up sponge back in the water it would reaggregate to form a new sponge. An example of a sponge that can do this, is a common sponge of the Northwest Pacific called Haliclona sp., a purple, low intertidal sponge species.

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Mystery sponge - Received from Brandy in Montana.

Q: I need to know as much information about the aplysing lonsissma sponge. Information such as their habitat, physical features, special characteristics, and whether they live alone or in a colony.

A: I believe the species you're referring to is Aplysina longissima, a member of the Family Aplysinidae. This family contains sponges with encrusting, massive, club-shaped and fan-shaped growth forms. The genus Aplysina is characterised by a marked aerophobic colour change from yellow or green to darker colours. Their fibers interlace to form a regular pattern with large hexagonal meshes and no specialized surface arrangement.

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First Sponge Genus - Received from Abby in Austin, Texas

Q: What is the genus of what was probably the first sponge on earth?

A: In 1996, Gehling and Rigby identified and described the first probable sponge, Paleophragmodictya, from the Ediacara of Australia. Their specimens revealed a reticulating net of spicules in the sponge body wall, reminiscent of that seen in many hexactinellid sponges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.

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see also: OceanLink's Porifera page!

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