The bacterium clings to the plastic and, if possible, ‘surfs’ across the oceans.

Researchers write that in the magazine Environmental Pollution† They base their conclusions on a rather unusual study in which they place a lander fitted with two common types of plastic – polyurethane and polystyrene – on the 1,800-meter-deep patch of the Atlantic Ocean floor. After some time, the researchers retrieved the lander to find out which bacteria had adhered to the plastic.

Results

The researchers then found bacteria on the plastic that we previously did not know would like to adhere to plastic. Halomonas titanicae is a good example of this. The bacterium was – as the name suggests – isolated for the first time on the remains of the famous ship RMS Titanic. There, the bacteria feast on rust. But research now shows that the bacterium also likes to attach itself to plastic.

extremophiles

In addition to this bacterium, the researchers found many more bacteria on the plastic, including so-called extremophiles: bacteria that can survive under extreme conditions. Examples are calorithrix and Spirosoma† bacteria that can also be found in hydrothermal vents and Arctic permafrost respectively.

Here you see the lander that the researchers put on the bottom of the ocean. There are two different types of plastic on board the lander. Image: Newcastle University.

pathogen

Somewhat worryingly, the conclusion is that also Aliivrio clung to the plastic. This pathogen already has a negative effect on fish farming in several places. The fact that the bacterium also likes to attach itself to plastic may be a cause for concern in view of the growing amount of plastic in the oceans.

All the more so, because the smaller pieces of plastic we see in the oceans move easily. And with that, the bacteria that attach themselves to the plastic – including these pathogens – may be able to move quite easily from one area to another and even reach apparently relatively isolated areas.

More insight into how (micro)plastics in the deep sea and the organisms they encounter there decay is important, says researcher Max Kelly. “The deep sea is the largest ecosystem on Earth and probably the final resting place for most of the plastic that ends up in the seas. But it is also a difficult place to study. Now that deep-sea experts, engineers and marine microbiologists have joined forces, our research team can provide greater insight into the bacterial community that adheres to plastic, and thus reveal more about the ultimate fate of plastic in the deep sea.”