Ocean Cleaners Under Threat

Article | Updated 9 months ago

When you think of sponges, the first thing that comes to mind would probably be the cleaning sponge in your kitchen. Believe it or not, those cleaning sponges used to come from the ocean. Divers walked along ocean floors plucking sponges off the sea bottom.

Sponges Bleach Too

Did you know, just like corals, sponges bleach too? This happens when micro-organisms, zooxanthellae or cyanobacteria that reside in the tissues of sponges die or leave the host sponge.

The tiny plant-like organisms called zooxanthellae live in the tissues of many animals including corals, anemones, jellyfish and sponges. They capture sunlight and convert it to energy, just like plants, providing important nutrients to the sponges. Zooxanthellae can die when the ocean conditions change in heat waves and acidification events.

What role do sea sponges play in our oceans? Being filter-feeders, the tiny pores in sponges make really important and massive filters, keeping our seawaters in good conditions for other sea animals.

Key points:

  • Similar to corals, sea sponges bleach too.
  • Sponges help keep our oceans in good conditions.
  • The tropical whip sponge of Pilbara and Kimberley region has recently been more correctly classified and given a name change.
  • Oceans are being perturbed and it’s time we act now.

What’s in a name

Found abundant in the waters up north in the Kimberley and Pilbara is a common and sizable sponge that recently underwent a name change.

Known as the tropical whip sponge due to its body shape, the species from Indonesia was first described as Dendrilla lacunosa in 1912. 100 years later, its been studied in the Pilbara and Kimberley regions of Western Australia.

During fieldwork with by the WA Marine Science Institution (WAMSI), Dr. Jane Fromont, Western Australia Museum’s sponge taxonomist noticed the large, whip-like properties of Dendrilla sponges to be extremely unusual. These shallow water sponges found at around 10 metre depth, were typically small and delicate. She decided to gather the help of a few international sponge experts to find out if this sponge was really a Dendrilla or not.  

Sea sponge

Ernstilla lacunosa
Image copyright 
Christine Schönberg

With the help of some fancy molecular techniques, a team of international sponge scientists established a new family of sponges. Instead of being a Dendrilla, this tropical whip sponge now belongs to the Ernstillidae family, an entirely different subclass.

Underwater diver Dr Jane Formont

Dr. Fromont out in the field
Image copyright WA Museum 

This name change is equivalent to having humans (Homo sapiens) being taken out of the subclass Placentalia (describing primates), and reclassifying them into subclass Marsupialia with all the kangaroos.

This just shows how little we know, and still have to find out about our oceans and the organisms that live in it. What’s unfortunate is that some species go extinct before we’ve even got the chance to study them, or before they’re even given a name.

The ocean would not what it is and would not be able to host beautiful species of whales, dolphins and sharks, if there weren’t corals and sponges on the bottom taking care of the filtering. With higher global temperatures, climate change and bleaching events occurring in recent years, it puts this system in danger. The balance of our oceans are also perturbed, it’s time to act now.

Siti Mutaza – Science Communication Practicum
University of Western Australia Student