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Sponges

Holly Chesmore

Historical Geology

Spring 2009

Sponges

 

Sponges are one of the most primitive animals that live in the ocean and have been in existence since the late Proterozoic.  They are sessile, multicellular, filter feeders with no definite symmetry.  They are called Porifera because they are pore bearing.  They have a unique body plan of canals and chambers that connect to the open pores on their surface.  Sponges eat by pumping water through their smaller pores called ostia, taking out the nutrients, and then releasing the waste through their larger pores called oscula.  They have no centralized gut, front or back.  Sponges also lack nerves and muscle, which means their only movement is by the individual cell crawling.  

 

 

All but one group of sponges are marine, and grow in all depths of the sea.  Those living in calm water tend to grow into tall, symmetrical, and bushy forms, while those that live where currents flow tend to develop low, encrusting shapes. 

 

                                                                                              Photo by UCMP

 

There are an estimated 15,000 sponge species living today, but only half of them have been described and named.  There are three classes of sponges that have been defined.  Demosponges are cellular and supported by a siliceous skeleton of two- and four-rayed spicules, which are made of silica or organic fibers that serve as supports.  Hexactinellida, or glass sponges, have a six-rayed glass skeleton and are syncytial rather than cellular.


Photo is copyright free for non-commercial educational uses. 
Just credit photo to R.Weller/Cochise College.

 

Calcareous sponges make up less than 5% of living sponges and are characterized by a calcium carbonate skeleton and cellular organization.  This is the only group in which the three grades of sponge body design are apparent.  These three groups include the Asconoid, which have cylindrical hollow bodies, straight canals, and tend to grow in groups; the Syconoid, which are similar to the Ascenoid but have a thicker body wall, branched canals, and do not normally form in groups; and the Leuconoid, which are the most common modern sponges that have a longer canal with more branches that lead to  specialized chambers, and live in large groups with each sponge still having their own canal system, but tending to act as one large organism.

 

Barrel Sponge

Photo by PBS shape of life
 

Tube sponges

Photo by PBS shape of life
 

Branching sponge

Photo by PBS shape of life
 

Indonesian sponge

Photo by PBS shape of life

 

Most people think of sponges as small and colorless or dull.  Actually, some sponges can grow to over 6 feet in diameter and can be a variety of colors.

 

Tube Sponge (Callyspongia vaginalis)
Photo Corel Corporation

 

Tube Sponge
(Callyspongia vaginalis)

The tube sponge is one of the most common varieties of sponge to be found on the reef.  It is distinguished by its long tube-shaped growths, and ranges in color from purple to blue, gray, and gray-green.  Filtered water is ejected through the large openings on the ends.  This is one of the few coral reef invertebrates that are blue in color.

 

 

Vase Sponge (Ircinia campana)
Photo Corel Corporation

 

Vase Sponge
(Ircinia campana)

The vase sponge is a common species found in the Caribbean off the eastern coast of Florida.  It is characterized by a large bell shape with a deep central cavity.  This sponge grows up to 2 feet wide and 3 feet high.  It ranges in color from purple to red and brown, and is found attached to rocks near the sandy bottoms.

 

 

Yellow Sponge (Cleona celata)
Photo Aris Entertainment

 

Yellow Sponge
(Cleona celata)

This small yellow sponge species is commonly found throughout the Pacific coastal waters of the United States.  It grows in small colonies and ranges in color from orange to bright yellow.  This sponge can be found encrusting rocks on the coral reef face.

 

 

Red Tree Sponge (Haliclona compressa)
Photo Corel Corporation

 

Red Tree Sponge
(Haliclona compressa)

This bright red sponge species is very common throughout the Caribbean Sea and usually grows to a height of about 8 inches.  This species is easy to keep in a home aquarium, but requires a moderate water flow and dim light to do well.

Photos by real life sponges

 

Most sponges are hermaphroditic; however they are only one gender at a time.  They can reproduce sexually or asexually.  To produce sexually, sperm is released into the canal of one sponge, and then pumped out through the osculum, top, into the surrounding water, where it then flows into the canal system of another sponge and reaches the egg.  When the larvae is ready, it is released from the parent sponge into the surrounding waters, where it swims or crawls around and eventually settles to grow into a new individual sponge.  Sponges reproduce asexually by releasing special groups of cells called gemmules into the surrounding water which eventually germinate under the right conditions and also grow into a new sponge.

One of the most amazing things about sponges is there ability to recover from damage.  Because the cells are not linked in a tissue, it is possible for them to be separated and then come together again to form a new sponge.

 

References:

Science Week http://scienceweek.com

http://www.ucmp.berkeley.edu/porifera/porifera.html

http://www.earthlife.net/inverts/porifera.html

G:\real life sponges.mht

http://www.pbs.org/kcet/shapeoflife/animals/porifera.html

http://shywalker.cochise.edu/wellerr/aawellerweb.htm