It is a rather special and indeed specialist day today: it is #spongethursday, a component of the 11th World Sponge Conference (I’d add the logo, but it closely resembles a pink Covid symbol). Poriferaphiles everywhere should be celebrating these beautiful creatures today. Here are some gorgeous examples. Now you know why sponges deserve a day of their own.
Candelabra Songe (with brittle stars attached)
Black Ball Sponges
One for Valentine’s Day
Spawning Brown Encrusting Sponge
All photos: Melinda Riger, Grand Bahama Scuba – with thanks as ever
The Purple Vase is an unmistakeable sponge, a colourful reef creature (for they are animals, of course) that stands even out amongst the bright corals that surround it. And like corals, sponges are vulnerable to all the usual threats (mainly human-generated).
Catch them while you can in the clear waters of the Bahamas while stocks last. I say this because as study after study concludes, the prospects of reef-mageddon get closer each year. When the corals die off, so in all probability will the sponges and anemones…
After such a depressing intro, let’s move on to take a positive look at the purple vase sponge. As with all sponges, once a newborn sponge is wafted by the current to a place on the reef, it takes root there throughout its life. There, these attractive sponges exist by filtering the water that surrounds them, separating out plankton to feed on. Static filter-feeders, if you will.
You’ll notice that in some of the photographs, the sponges have guests. These are BRITTLE STARS, and they are often found on – and indeed in – purple vases. This is a form of symbiotic relationship known as commensalism, in which one species benefits and the other is neither benefitted nor harmed. The brittle star gains a shelter and a safe base for feeding; the vase gets a harmless companion. Small fishes benefit from the vases in a similar way.
Besides the impact of damaging human interventions (which may be permanent), extreme weather events also affect reef life and the static inhabitants adversely. Storms and hurricanes can cause localised havoc, but the damage is not necessarily permanent. The reef can in time repopulate naturally and flourish again. Humans can even promote this recovery. The photograph above shows a purple vase sponge that was detached from the reef by Hurricane Matthew in October 2016. Melinda Riger in effect replanted it on the reef and it reattached itself and grew. In due course it even acquired its brittle star occupant.
*JIMI AND ‘PURPLE VASE’ – A VOLUNTARY MUSICAL DIGRESSION
In an interview with NME Hendrix is reported to have said that Purple Haze “was about a dream I had that I was walking under the sea.” Originally the song was intended to be ‘Purple Vase’, and reflect the psychedelic experience of life on a coral reef. Realising he was getting bogged down by sub-aquatic imagery (he was a non-swimmer), he toked for a while and then ‘Purple Haze’ emerged almost fully formed. He was always far happier kissing the sky than wandering about under the waves. Most covers of the song are pale imitations of the original, but here’s a rather unusual take that succeeds by trying a different approach…
Credits: Melinda Riger / Grand Bahama Scuba for all great photos; magpie pickings for bits and pieces, with a shout-out to ‘Critter Squad’ for its informative site aimed at kids. And amateur grown-ups can benefit too… commensalism in humans; Friend ‘n’ Fellow audio
A while back I showed a collection of colourful sponges – one that you might come across with minimum equipment. Snorkel, mask, flippers. Oh, and a coral reef, if you happen to have one handy. I suspect that to quite a few people the word ‘sponge’ means soggy yellow thing, as found in the proximity of a bath. Or a scratchy nylon-based equivalent. Well, here are a few more sponges to enjoy. Some I can give you the names of, some I don’t know and am too idle busy to look up… Sorry.
It’s time to take an up-close look at some of the sponges you may find as you snorkel or scuba round the reefs of the Bahamas. I am always amazed by how bright and colourful they are, and by their many different shapes and sizes. Even the unpromising sounding (slightly medical, even?) BROWN TUBE SPONGE turns out to be fascinating to examine closely. Here are some more sponge species.
STOVE PIPE SPONGE
PURPLE VASE SPONGE
BRANCHING TUBE SPONGE WITH ROPE SPONGE
PURPLE TUBE SPONGE
PURPLE SPONGE WITH GIANT ANEMONE
The above sponges represent a fraction of the sponge varieties found on Bahamas reefs. I’ll post some more quite soon. All this has made me want to go for a snorkel. But right now I am 30 miles from the sea. And I have no gear…
HANG ON A MOMENT! WHAT IS A SPONGE WHEN IT’S AT HOME?
It’s really very simple: if you are ever asked the question, just reply “a sponge is a primitive sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibres or calcareous or glassy spicules. Sponges draw in a current of water to extract nutrients and oxygen”.
AND WHAT, PRAY, IS A SPICULE?
You’re having a laugh… if you seriously want to know, read the abbreviated version about themHERE. And admire this microscopic collage of ‘demospongiae spicule diversity’ made available by the wonders of Wiki and the research of about 20 credited scientists.
All photos: Melinda Riger, Grand Bahama Scuba. Tip of the hat to Wiki and scientists