Imagine a raft of sea ice in the Arctic Ocean, and you probably envision a flawless marriage of white and blue. But in summer, something much greener and gooier lurks beneath the surface. a species of algae, melosira arctica, grows in large, dangling masses and curtains clinging to the underside of Arctic sea ice, mostly obscured from a bird’s eye view.
Composed of long threads and clumps of single-celled organisms called diatoms, the algae are a key player in the polar ecosystem. It is food for zooplankton, which in turn feeds everything from fish to birds and seals to whales – either directly or through an indirect, upward cascade down the Pac-Man-like life chain. In the deep sea, benthic creatures also rely on preparing meals from sunken clumps of algae. After an assessment M.arctica billed about 45% of arctic primary production in 2012. In short: the algae support the entire food web.
But something else abounds in the hidden, slimy world of ice cream foam: microplastics. Researchers have documented alarmingly high concentrations of tiny plastic particles in samples from M arctica, after a new study published Friday in the journal Environmental Science & Technology. The work adds to the growing evidence that microplastics really are everywhere: in freshly fallen Antarctic snow, the air, baby poop, our blood-overall.
All 12 algae samples that the scientists collected from ice floes contained microplastics. In total, they counted around 400 individual pieces of plastic in the algae they examined. Extrapolating this to a volume concentration, the researchers estimate that each cubic meter M.arctica contains 31,000 microplastic particles – more than 10 times the concentration they found in the surrounding seawater. It could be bad news for the algae, the organisms that depend on it, and even the climate.
Although microplastics are seemingly ubiquitous, the results were doubly surprising Melanie Bergman, first author of the study and biologist at the Alfred Wegener Institute in Bremerhaven, Germany. In an email, she told Gizmodo that she didn’t expect to document it such high amounts of microplastics in M.arctica, yet to be for these concentrations so much higher than what was in the water. But in hindsight, it probably explains the gummy nature of the algae.
Sea ice itself contains a lot of microplastics (up to millions of particles per cubic meter, depending on location, acc previous research miner continued). Sea ice both binds plastic from the ocean through its freeze/melt cycle and collects pollution from above as it is deposited by wind currents. This sea ice contamination, in turn, likely leaches to the algae. “When the sea ice melts in the spring, microplastics are likely to be trapped [by] their sticky surface,” Bergmann assumes. And both ice floes and attached masses of algae move about, picking up plastic particles as they follow ocean currents.
Within the Arctic marine ecosystem, previous research has found the highest levels of microplastics in sea floor sediments, the biologist explained further. The algal cycle could explain a large part of these plastic deposits. By getting caught in a dirty web of M.arctica Filaments, the tiny pieces of man-made garbage, hitchhiking to the bottom of the ocean. Large chunks of algae sink much faster than tiny pieces of debris, which tend to float in the water column. So, on the plus side, the new study solves something of a conundrum. But the benefit of the new knowledge is perhaps the only silver lining here.
Since the algae are the scaffolding of an arctic food web, anything that eats them (or eats something that eats them) will almost certainly ingest any plastic within. The health effects of microplastics aren’t well established yet, but some early studies suggest they’re probably not good for the people or wildlife. In this way, M.arctica‘S sticky The affinity for plastic could slowly poison the entire ecosystem.
Then there’s the way the pollution could damage the algae itself. Laboratory tests of other types of algae have shown that microplastics can prevent the ability of an organism to photosynthesize and damage algal cells. “We don’t yet know to what extent this occurs with different algae and whether it also affects ice algae,” says Bergmann; The effects of microplastics appear to vary greatly depending on the species, she added.
But in the age of climate change, any additional stress on already rapidly changing Arctic systems is undesirable. And if algae are indeed less able to photosynthesize when stuffed with plastic, then they are also less able to sequester carbon and less mitigate climate change — a small but potentially significant Arctic feedback loop, explained she.
All of this is still a question mark for now. More research is needed to understand how microplastics travel through the food web and what it does to the organisms that ingest them (Bergmann hopes to conduct future studies specifically on the deep-sea creatures that live among the plastic-infested sediments). But if scientific experiments don’t soon uncover the consequences of our plastic addiction, time likely will. “As concentrations of microplastics increase, we will see an increase in its impact. In certain areas or species, we can exceed critical thresholds,” said Bergmann. “Some scientists believe we already have.”