We usually think of ecosystems as fairly static, moving over hundreds of years, not days or weeks. But some of Earth's ecosystems are actually defined by constant movement — and so it is with the neuston. This understudied zone is right at the water's surface, both above and below.
It contains bacteria, protozoans, certain species of fish, jellyfish, sea anemones, crabs and velellas (those blue floaties that land on beaches and are also called by-the-wind sailors). They can be found in freshwater ponds and lakes, too — water skeeters or gliders are one of the bugs that's a part of the neuston in that scenario.
In the ocean, the neuston moves passively, following the currents, and can be found thousands of miles from shore. If this sounds familiar to the plastic in the garbage gyres that plague oceans worldwide, that's no coincidence. The neuston territory and the gyre territory overlap completely.
You can see evidence of that in the collection made in the video above, which features both a jellyfish and plastic bits that researchers are counting for an ocean survey.
So, if we clean up the plastic — using a method like the Ocean Cleanup project, which involves giant booms essentially sweeping the surface of the ocean — we also could also clean out the neuston.
And that's a problem. The neuston is an important ecosystem, and its health affects other ocean systems. Like a reef, or the shallow banks of places like the inter-island zones of the Bahamas, the neuston serves as a nursery for some fish, which also makes it an ideal place for other animals like leatherback turtles, octopuses and other fish to hunt for easy food.
Neustons are also complex ecosystems. Rebecca Helm, a jellyfish expert who is a professor at the University of North Carolina at Chapel Hill, writing in The Atlantic recounts how little has been written about the neuston and her difficulty in finding materials. She finally found a few journal articles about the neuston, written by a Russian oceanographer A. I. Savilov who had done surveys across the Pacific.
Savilov described seven unique neuston meadows in the open ocean, each with its own unique composition of animals. Just as rainforests differ from temperate forests, these neustonic ecosystems are unique. And one of them, Neuston Ecosystem 2, is in exactly the same spots as the "garbage patches" where the Ocean Cleanup plans to operate. This makes sense: The neuston ecosystem is entirely passive — floating just like plastic — and evolved over millions of years to thrive within these regions, where surface-bound objects collect.
But we know so little about this ecosystem — which means we could lose it before we've even gotten to know how important it is beyond the basics.
Helm makes an important and eloquent point:
The Ocean Cleanup says it wants to protect animals at the ocean’s surface from plastic, but neuston is the ecosystem of the ocean’s surface. There is a reason turtles and sunfish eat floating surface plastic: It looks like neuston. Using these wall-like barriers to collect plastic in spite of the neuston is like clear-cutting a canopy in the name of helping a forest. There is no point in collecting plastic if by the end there is nothing left to conserve.
The Ocean Cleanup group responded to Helm's story with its own point: The plastic already threatens the 117 endangered ocean species that live there, and it's causing ongoing damage to that ecosystem. "There is strong evidence that the hundreds of thousands of tons of toxic plastic that is floating in the ocean is damaging ecosystems, which, ironically, may include the neuston," said Claire Verhagen, a spokesperson for The Ocean Cleanup, in an email.
Clearly we need to understand more about the neuston — and the creatures that live there, like the one you see the in the video below. Especially before we drag it with giant booms in our quest to rid the oceans of plastic.
Editor's note: This story has been updated since it was originally published in early February 2019.