Nearly all seabirds have ingested microplastics

The pervasive nature of anthropogenic plastic pollution extends beyond the often-visualized scenes of marine wildlife entangled in debris, reaching the remote and pristine polar regions of the Arctic and Antarctica. 

Here, not only macroplastics but also microplastics (0.1 µm—5 mm) and nanoplastics (<0.1 µm) find their way onto floating ice and terrestrial landscapes, transported vast distances or ingested by migratory species from more populous areas. 

Seabirds and microplastics 

In a comprehensive review led by Roma Tre University in Italy, scientists have synthesized four decades of studies, from 1983 to the present, on the ingestion of microplastics by seabirds residing in these regions.

“The Arctic and Antarctica represent two of the most inhospitable and poorly investigated biomes in the world. Although polar regions are still perceived as some of the most pristine places still in existence, these remote places are no longer immune to anthropogenic pollution, in particular, micro- and nanoplastics,” wrote the study authors. 

“Seabirds, avian species feeding mainly at sea, are indicators of change in the environment and represent an early study group of ecological indicators for plastic pollution.”

Focus of the study 

Analyzing over 1,100 samples, the team investigated the presence of microplastics in various components including stomach contents, crop pouches (used for temporary food storage during foraging trips), guano (a mixture of food and metabolic waste), and regurgitated pellets containing undigested food and other particles.

Predominantly, the study focused on pellets, with stomach contents and guano following in frequency, and minimal data on pouch contents.

Seabird species from polar regions

In their review, the researchers identified 13 seabird species from polar regions reported to have ingested microplastics.

These species encompass little auks, northern fulmars, glaucous gulls, thick-billed murres, white-chinned petrels, great shearwaters, sooty shearwaters, king penguins, Adélie penguins, chinstrap penguins, gentoo penguins, brown skuas, and south polar skuas. 

Staggering presence of microplastics 

From these birds, a total of 3,526 microplastic particles were extracted, revealing a staggering prevalence of at least one microplastic particle in 90% of Arctic samples and 97% of Antarctic samples. 

The study noted a median of 31.5 and 35 microplastic particles per sample in the Arctic and Antarctica, respectively, with a single bird harboring up to 36 particles.

The composition of these ingested plastics spanned 14 polymer types, with polyethylene, polypropylene, and polystyrene being the most common, often manifesting as fragments from the breakdown of larger plastic items such as bags, food containers, and foam packaging.

Broader ecological implications 

The ingestion of these microplastics poses significant risks to seabirds, including gastrointestinal blockage, toxicity, oxidative stress, and immune reactions. 

Moreover, the presence of microplastics in krill, a primary food source for certain penguin species, underscores the broader ecological implications and the potential disruption of trophic webs.

Urgent need for conservation efforts 

With 64 seabird species in the Arctic and 43 in Antarctica, witnessing declining populations, there’s an urgent call for enhanced conservation efforts. 

The Arctic, covering about 6% of Earth’s surface, faces additional anthropogenic pressures from tourism, commercial fishing, increased maritime activity, and the consequences of global warming on ice melt and subsequent environmental changes.

This review underscores the global reach of human activity, impacting even the most remote and untouched parts of our planet. It emphasizes the need for continuous dialogue and action to mitigate environmental stressors and protect biodiversity in the Arctic and Antarctica from the encroaching threats of plastic pollution and beyond.

The study is published in the journal Frontiers in Marine Science.

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