These Are a Few of My Favorite Species: Carnivorous Sponges

Most sponges, inspiration for dish cleaners and mess absorbers, feed by filtering water through those many holes and channels.  Their scientific name, Porifera, literally means pore bearer.  The channels are lined with special cells, chanocytes, each containing a flagellum that continuously beats.  This whirling action by the flagellum filters nutrients and small particles of food from the surrounding water.  With the particles near, the cell quickly engulfs by wrapping part of its membrane around it like a puppy lost in blanket.  However, in this metaphor the puppy is digested by a dog-sized cell.

Our Deepwater Backyard: Exploring Atlantic Canyons & Seamounts
Image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014.

Flagellum and ingesting puppies, metaphorically speaking, is the norm for most sponges.  However, in the dark depths of oceans and in the black caverns of the marine caves, lurks Earth’s strangest creatures—the carnivorous sponges.

This closeup could almost pass for a flower in your garden, but appears to be a sponge – probably a “carnivorous sponge” of the cladorhizids. Image captured by the Little Hercules camera at about 1000 meters depth. Image ID: expl5560, Voyage To Inner Space – Exploring the Seas With NOAA Collect Photo Date: 2010 July 5 Credit: NOAA Okeanos Explorer Program, INDEX-SATAL 2010

Most sponges are composed of spicules, little shards of silica, that provide structure.  In the carnivorous sponges, Cladorhizidae, some spicules are shaped like hooks.  Unsuspecting tiny crustaceans or other animals near the sponge are often caught in the sheets of hooks that line the surface of the Cladorhizid sponges, much schmutz in Velcro.  In some Cladorhizids copepods may be caught by an adhesive surface.  Once a crustacean is caught, the cells surrounding mobilize, cover, and create a temporary cavity around the crustacean.  Within this cavity the crustacean is digested.  It’s the equivalent of mosquito being caught in your arm hairs, the skins cells then form a layer of skin over it, and finally you digest the mosquito just below the surface of the skin.

Here is the link to a Google Image search so you can see the wide variety of forms these magnificent beasties take.