A disturbing new study by researchers from the University of Basel and the Alfred-Wegener Institute (AWI) brings to light the alarming extent of microplastic contamination in the Weddell Sea, a remote part of the Antarctic Ocean.

Their spring 2021 expedition data reveals a situation far more severe than previously recognized.

Tiny particles, titanic problem

In the context of growing environmental concerns, the term ‘microplastics‘ refers to minuscule plastic fragments, typically smaller than 5 millimeters in diameter.

Consequently, these particles often originate from the gradual breakdown of larger plastic objects. Over time, environmental factors like sunlight exposure, wave action, and physical wear cause these objects to deteriorate.

Moreover, microplastics include intentionally created tiny plastic beads used in cosmetic products like exfoliating face washes and toothpastes.

The issue with microplastics lies in their propensity to infiltrate aquatic ecosystems, leading to ingestion by wildlife under the mistaken belief that they are food.

This poses a direct threat to marine and freshwater species and carries broader implications for human health and environmental integrity.

Related video: Why Isn’t the Arctic Ocean Full of Freshwater Anymore? (Dailymotion)


Analyzing microplastics in Antarctica

The research team analyzed 17 seawater samples from the Weddell Sea. They found significantly higher concentrations of microplastics than those reported in earlier studies.

Subsequently, Clara Leistenschneider, the study’s lead and a doctoral candidate at the University of Basel, credits the discrepancy to their innovative sampling method.

Unlike traditional techniques, which use fine nets to capture particles larger than 300 micrometers, their approach targeted a wider range of particle sizes, from 11 to 500 micrometers.

Employing this method, which involved pumping water into tanks, filtering it, and analyzing it with infrared spectroscopy, the team made a striking discovery.

They uncovered a staggering 98.3 percent of plastic particles smaller than 300 micrometers — sizes likely overlooked by previous studies.

“Pollution in the Antarctic Ocean goes far beyond what was reported in past studies,” Leistenschneider remarks, underscoring the gravity of their discovery.

How microplastics reach Antarctica

The study also delves into the factors influencing the distribution of microplastics in the Weddell Sea. Samples collected north of the continental slope, particularly in areas influenced by the Antarctic Slope Current, showed the highest concentrations.

While the precise reasons for this pattern remain uncertain, researchers speculate on the role of coastal ice and ocean currents in trapping and releasing microplastics.

Gunnar Gerdts from the AWI proposes a theory regarding ocean currents. He suggests they might act as a barrier, limiting the exchange of water — and thereby microplastics — between the ocean’s northern and southern parts.

Tracking microplastics beyond the ocean’s surface

Further investigation is needed to understand the vertical distribution of microplastics, as the study focused solely on surface waters.

However, challenges like limited sampling time and inadequate equipment have hindered a comprehensive analysis of deeper waters.

Such an analysis could uncover different dynamics, given the contrasting nature of deep and surface currents.

The origin of these microplastics in the Weddell Sea remains a puzzle, sparking significant scientific inquiry.

On one hand, possible sources include local ship traffic from tourism, fishing, and research activities. On the other hand, distant regions could contribute through ocean currents or atmospheric transport.

Amidst these uncertainties, one thing is clear: the enduring presence of microplastics in the Antarctic waters poses significant ecological risks.

This situation is potentially exacerbated by the strong Antarctic Circumpolar Current, which may hinder these pollutants from leaving the area.

Microplastics and the future of Antarctica

Leistenschneider plans to study sediment samples to understand microplastic seabed accumulation and its impact on Antarctic icefish habitats. She notes the need for action, especially as Antarctic tourism grows.

She remains hopeful, citing increased global awareness and efforts to combat microplastic pollution. “Research on the topic has dramatically increased awareness in recent years of the problems that microplastics cause for the environment and all living organisms,” she states, advocating for individual responsibility and global solutions.

Overall, her research aims to highlight and address the critical yet overlooked problem of microplastics in Antarctic waters, urging a collective reassessment and action plan.

The full study was published in the journal Science of The Total Environment.


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