By Dave Sigworth, Maritime Aquarium publicist
This week brought more amazing news about sponges. We’ve been long-time big-time fans, and the latest news makes us even more convinced that you too should be grateful for the simple humble sponge.
It was cool enough, a few years ago, when genetic researchers announced that they believe sponges were the first organisms on Earth to develop more than one cell, meaning that all multicelled animals since then – and that includes you – can trace their family trees back to those innovative ancient sponges.
Now, this week, a team of British researchers said they think sponges provided the initial oxygen that was needed to kickstart greater animal life on Earth.
In an article titled “Take A Breath and Thank A Sponge,” The New York Times reported that a team led by Dr. Timothy Lenton of the University of Exeter may have solved the mystery of what force millions of years ago raised oxygen levels in the ocean high enough to support complex oxygen-breathing animal life. They think it was sponges. Here’s the article.
At first glance, of course, sponges may seem about as exciting as a head of colored cauliflower. They don’t really move. You can’t make eye contact with them. They don’t bite. Except for maybe fire sponges, which are toxic to the touch, they’re not scary.
But did you know that sponges feed without having any sort of mouth or digestive system? And that if you (cruelly) ran a live sponge in a blender, its cells – like something out of a science-fiction horror movie – would wriggle back together and eventually form a new sponge again?
Sponges are found in all the oceans. Here in Long Island Sound, there are just two species. One is boring – literally. It bores holes into clam and oyster shells. The yellow boring sponge (Cliona celata) isn’t trying to get at the clam or oyster meat; it just wants to firmly anchor itself down on a shell. (If there’s a mollusk still alive inside the shell, however, the result is usually fatal.)
The yellow boring sponge and some other sponges are encrusting, meaning that they cover a surface like moss covers a rock. Other species of sponges stand upright off the sea floor, such as Long Island Sound’s other native sponge – the red beard sponge (Microciona prolifera). Red beard sponges grow on rocks, shells and pilings, forming dense clusters of fingerlike lobes that grow about 5 inches high. The sponge is reddish-orange but quickly fades to a grey-brown when brought out of water.
(Come out this summer on the Aquarium’s hands-on Marine Life Study Cruises and you’ll most likely see one or both kinds of sponges come up out of the water.)
Yellow boring and red beard sponges feed like all other sponges feed: by filtering tiny organisms, some as small as bacteria, out of the water. Sponges are full of tiny holes and canals, into which sea water flows. Special cells capture the food. Filtered water and the sponge’s wastes are expelled through larger holes called oscula.
Sponges draw in water constantly. It’s been estimated that, in one day, a sponge the size of a gallon of milk can filter as much water as is in an average backyard swimming pool. By doing so much filtering, sponges help to keep marine habitats clean.
Just another reason that we’re indebted to sponges.
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