Day 10 & 11: 30 June – 1 July 2020

What‘s this? It looks like a rusty can of some liquid or food – did someone drink a soda and it ended up 3700m deep being the new home of pantopods, amphipods, sponges and cnidarians?
What‘s this? It looks like a rusty can of some liquid or food – did someone drink a soda and it ended up 3700m deep being the new home of pantopods, amphipods, sponges and cnidarians?

Another day with a successful ROV dive finished. We observed various different species and traces – from the most peculiar feeding trails made by Holothurians (sea cucumbers), tracks from trawling nets, piled up sediment with a wormhole on top (which resembles a mini volcano), small red shrimps drifting slowly through the water, and lovely sponges in the middle of the deep-sea desert that are blooming with life and give home to a lot of small creatures. A lot of the species are known already and can be identified in real time by the deep-sea life experts on land who are watching the video stream and tune in on board via live chat.

Beautiful sponges growing on consolidated sediment substrate - this one is probably over 700 years old.
Beautiful sponges growing on consolidated sediment substrate - this one is probably over 700 years old.

 

All of a sudden during our journey along the seafloor, the environment has changed and we are facing a massive slope which is quite steep. This is probably the remnant of giant debris flows of former times and moving plates, when the Aegir Ridge was still tectonically active. A consolidated sulphite substrate bottom is home to various species of crustaceans, sponges and also polychaetes – little worms that live in/on the benthos. Surprisingly, not one single fish was around although this region is known to be a popular fishing area. Just before the ROV ascended back to the ship, we found a plastic tube sticking in the seafloor. It was already forming a home for an anemone and decapods – a literally living example of the fate of litter on the deep-sea floor.

 

Cleaning the ocean floor!
Cleaning the ocean floor!

Once it sinks, it rapidly becomes a vivid habitat to all sorts of animals. However, it also starts to decay, falling apart into smaller and smaller pieces until it is broken down to sub-millimetre sized pieces. These are taken up by the tiniest animals in the food chain, those are eaten by the next bigger ones and so on and so forth, until it is everywhere, in every body. This is not only theory, let’s face it – our biologists on board have already found microplastic in the sediment from 3000m water depth when examining the MUC, EBS and box core samples. It is already all around us and it’s probably impossible to ever totally free our oceans from microplastic again, but we should strive to stop putting more in.