It is not the primary study on microplastics in Antarctica that researchers from the University of Basel and the Alfred-Wegener Institute (AWI) have conducted. But evaluation of the information from an expedition in spring 2021 shows that environmental pollution from these tiny plastic particles is an even bigger problem within the distant Weddell Sea than was previously known.
The whole of 17 seawater samples all indicated higher concentrations of microplastics than in previous studies. “The explanation for that is the form of sampling we conducted,” says Clara Leistenschneider, doctoral candidate within the Department of Environmental Sciences on the University of Basel and lead writer of the study.
The present study focused on particles measuring between 11 and 500 micrometers in size. The researchers collected them by pumping water into tanks, filtering it, after which analyzing it using infrared spectroscopy. Previous studies within the region had mostly collected microplastic particles out of the ocean using positive nets with a mesh size of around 300 micrometers. Smaller particles would simply go through these plankton nets.
The outcomes of the brand new study indicate that 98.3 percent of the plastic particles present within the water were smaller than 300 micrometers, meaning that they weren’t collected in previous samples. “Pollution within the Antarctic Ocean goes far beyond what was reported in past studies,” Leistenschneider notes. The study appears within the journal Science of the Total Environment.
What role do ocean currents play?
The person samples were polluted to different extents. The offshore samples, which were collected north of the continental slope and the Antarctic Slope Current, contained the best concentrations of microplastics. The explanations for this should not conclusively known. It might be that the ice that tends to form near the coast retains the tiny plastic particles, and so they are only released back into the water when the ice melts. It is also the case that ocean currents play a task. “They may work like a barrier, reducing water exchange between the north and south,” suggests Gunnar Gerdts from the AWI in Heligoland, Germany.
What’s actually true is that ocean currents are a vital factor and the topic of many open questions in the sector. Thus far the researchers have only examined water samples from the ocean surface, but not from lower depths. That is primarily attributable to limited time on the ship expeditions for taking samples and to equipment with insufficient pumping capability. “It might nonetheless be revealing to investigate such data, for the reason that deep currents differ greatly from the surface currents and thermohaline circulation results in exchange with water masses from northern regions,” Leistenschneider says.
Additionally it is still unclear how the microplastics make their technique to the Weddell Sea in the primary place and whether or not they ever leave the region. The strong Antarctic Circumpolar Current, which flows all the way in which across the Antarctic Ocean at a latitude of about 60° south, might prevent their departure. The researchers are also not yet in a position to say conclusively where the microplastics originate. Possible sources include regional ship traffic from the tourism, fishing and research industries, in addition to research stations on land. Nevertheless, the microplastics may also make their technique to Antarctica from other regions via ocean currents or atmospheric transport.
Research results in awareness
Clara Leistenschneider plans to focus next on analyzing the sediment samples she collected in the course of the same expedition. This could provide details about how microplastics are accumulating on the ocean floor, which is home to unique and sensitive organisms and is a breeding ground for Antarctic icefish (Bovichtidae).
With the rise in tourism within the Antarctic Ocean, pollution may increase much more in the long run, further impacting the environment and the food chain.
Nonetheless, Leistenschneider stays cautiously optimistic: “Research on the subject has dramatically increased awareness lately of the issues that microplastics cause for the environment and all living organisms.” Although there is no such thing as a all-encompassing solution, she notes that quite a lot of stakeholders everywhere in the world are working intensively to higher understand the issue and develop progressive ideas to cut back plastic pollution. And, after all, “every individual who engages in environmentally-conscious behavior can bring about positive change.”
