Updated: Dec 10, 2020
It's that time of year - the Pogues are on the radio, the decorations in the attic are getting their yearly breath of fresh air, and it's started to feel a bit too chilly for your liking. You might not think it, but creatures of the deep sea are getting festive too.
Down in the depths of the ocean, where sunlight cannot reach, and organisms are few and far between, we find a few festive reminders of the sights and traditions of Christmas.
Watch the video:
This is a sea angel, a tiny pteropod that slowly waves its adapted wing-like parapodia to move through the water column. With its beautiful colours and transparent body, it's easy to see where it got its name. But despite their angelic appearance, they can be cannibalistic, hunting down fellow pteropods for a meal.
One tiny larvacean (below) has adopted an incredible adaptation. It builds a gigantic net made of mucus around itself, in order to capture another festive feature of the deep sea.
A constant stream of delicate particles, drifting ever-downwards into the deep sea. A beautiful sight, indeed, but these aren't the sort of snowflakes you'd want to catch on the tip of your tongue. Marine snow is, in fact, a drift of organic matter. That is to say, poop and dead stuff. It might not sound particularly appetising to us, but for deep sea organisms, it's delicious.
In fact, marine snow is perhaps the only reason that life is able to exist at all in the barren depths. Photosynthesising plants cannot exist in the darkness, so without marine snow, there would be no energy supply feeding most of the deep.
A Christmas Feast
We roast a turkey, they devour a dead whale. And in a similar fashion to our own festive meals, the leftovers last for 50 years, supporting an ever-changing biological community on the sea-floor.
The darkness of the deep sea twinkles. Little blue lights burst and flash, caused by the phenomenon of bioluminescence. Why is it blue? Well, it's because of the intermediate wavelength of blue light. Lights with long or short wavelengths aren't really expressed in the ocean, like red or violet. This same rule explains why the ocean itself appears blue.
Christmas Tree Worms
They're brightly coloured, covered in fine tapering hairs, and decorate reefs the way fir trees decorate our homes. The Christmas tree worm is a form of polychaete worm that uses the hair-like protrusions on its body to capture plankton drifting through the water column.
So there you have it. An insight into the all-year-round festivities that take place in the deep sea. To find out more about our oceans, visit our Deep Sea Hub.