Microplastics Affect Global Nutrient Cycle and Oxygen Levels in the Ocean

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The effects of the steadily increasing amount of plastic in the ocean are complex and not yet fully understood.

The effects of the steadily increasing amount of plastic in the ocean are complex and not yet fully understood. Scientists at GEOMAR Helmholtz Centre for Ocean Research Kiel have now shown for the first time that the uptake of microplastics by zooplankton can have significant effects on the marine ecosystem even at low concentrations. The study, published in the international journal Nature Communications, further indicates that the resulting changes may be responsible for a loss of oxygen in the ocean beyond that caused by global warming.

Plastic debris in the ocean is a widely known problem for large marine mammals, fish and seabirds. These animals can mistake plastic objects, such as plastic bags, for similar-looking food items, such as jellyfish. Tiny zooplankton can also mistake very small plastic particles for food and ingest them either accidentally or by chance (when the particles have combined with organic particles).

The direct effects of such microplastic ingestion on zooplankton are poorly understood, but the broader effects on ecosystems of zooplankton replacing some of their food with plastic are much less well understood. Now, for the first time, a research team has used an Earth system model to simulate how zooplankton that ingest microplastics could affect the base of the ocean food web and nutrient cycling. The results, now published in the international journal Nature Communications, suggest that even low concentrations of microplastics can have a strong impact on ecosystems. “This influence is already sufficient to affect global nutrient cycling”, says Dr Karin Kvale, lead author of the study.

Read more at Helmholtz Centre for Ocean Research Kiel (GEOMAR)

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