sponges on coral reefs

Role of sponges in a coral reef ecosystem

What images come to mind when you think of a coral reef? I don’t think it would be much of a stretch for me to guess that one of your top three images that came to your mind was certainly not of sponges.

If stony corals and clownfish are on the coral reef celebrity A-list, the lowly sponge would have to be on the C-list or lower (or is it sea-list…pun intended, unfortunately, but I couldn’t help myself). But despite their low-rank on the celebrity scale, it turns out that sponges are a surprisingly important part of the reef ecosystem.

sponges on coral reefs
image from wikipedia

According to a study published in Science, and reported on the BBC’s website, sponges recycle 10x’s as much matter as bacteria and contribute as much nutrition as all the algae and corals combined. That’s no statistic to be ashamed of.

Here is another impressive factoid: one of the species studied consumed 66% of its body weight in carbon each and every day.

Both of these points got me thinking…if sponges are this awesome, why don’t we see, hear or read much about them in the saltwater aquarium hobby. I thought for a few moments about it, and all I could come up with was advice (I don’t know from where) to be careful about sponges because they can leak toxic chemicals when they die.

But if Sponges are 10x’s as good at filtering the water as bacteria because they consume huge amounts (relative to their size) of carbon, why is it that we are so worried about the bacteria in our biological filter? Why do we rely on macro algae in our refugia for nutrient export? Why don’t we have designs for DIY sponge scrubbers (instead of algae scrubbers)? Why is it that I know almost nothing about sponges in aquaria?

Diversity tends to be something that helps the stability of almost anything…including populations of animals—I can’t help but wonder if we wouldn’t have better success with our tanks simply by including poriferans more deliberately into our tanks.  What do you think?






Leave a Reply

Your email address will not be published. Required fields are marked *