The Hardest Workers in the Ocean
Written by Roy Kittrell May 2024.
As Labour Day approaches this month, we take a look at some of the hardest workers across the ocean and in our reefs and celebrate the time and effort taken by these remarkable creatures to keep our ecosystems functioning and beautiful!
Phytoplankton
They say that every time someone wears a ‘save the rainforest’ t-shirt, a phytoplankton sighs. This is because, contrary to popular belief, the vast majority of the breathable oxygen (estimated to be more than 50%!) on our planet comes from photosynthesis done by these remarkable little organisms in our oceans! That’s right, the air you’re breathing right now, that allows you to live, came from the tireless work done by a microscopic organism.
Despite being so important for our day to day lives, you sure don’t see many hippies out campaigning to save the phytoplankton, despite the threat of climate change altering their abilities to do this.
Larvaceans
Imagine you’ve just dived into the black waters of Anilao on a nice, cool evening in the Philippines. You descend down towards the lights that are hanging to attract sea creatures for you to see. Suddenly, a tiny, thin tadpole-like creature with what looks like a slimy croissant attached to it’s back begins to swim past you. This is the Giant Larvacean and it’s doing very important work to keep our oceans free of microplastics!
Larvaceans are a branch of a fascinating type of animal called a tunicate, which are almost like a common ancestor we have between Hydrozoa and vertebrates. Tunicates for the large part don’t look like Larvaceans, most only look like this in the larval first part of their life cycle, before becoming benthic floor-dwelling filter feeding animals. The Giant Larvacean decided it would just stay at it’s juvenile stage forever, a phenomenon in Biology called Neoteny, and it also developed a few other pretty cool tricks.
One of them was the ability to build that large net of sticky mucus around itself. This filters large and small particles of food in the water column into it’s mouth, but it also catches other inedible particles like microplastics and filters them out of the water! When the larvacean is done feeding, it discards this net, and those particles fall to the ocean floor and are buried away forever.
The invaluable service provided by these amazing organisms is just one of the ways we can hope to start tackling the problem of cleaning our oceans, so let’s all thank these tiny and magnificent animals for their services!
Sponges
Admit it. You’ve been on dozens of dives, and you have some great videos and pics to show all your buddies on TikTok, Instagram, and whatever other social media you use. But when you are picking the pics to upload, which ones are you choosing? The ones of the cool looking turtles I would imagine. Maybe some colourful fish, some nudibranchs. But I’ll bet there are some organisms you didn’t take pictures of. I’ll bet you didn’t take any pictures of all the Sponges that live in our oceans, did you? DID YOU. Here they are, just quietly filter feeding thousands of litres of water a day PER SPONGE, for literally billions of years, not asking anything from anyone, keeping our waters clean and the visibility up, and you didn’t even take a single picture of them.
Sponges are one of the oldest kinds of organisms on Earth, and are vital to the health of all of our reef ecosystems clearing suspended sediment and bacteria which allows corals to thrive and get sunlight.
Next time you go diving I suggest you take a moment to say THANK YOU to a sponge, and apologise for the neglect to these amazing, wonderful, hardworking little organisms.
-Roy Kittrell is an avid naturalist and underwater photographer, his work can be found on Instagram @roythedivebro