Skip to content

Microplastics Were Found in All Studied Cormorant Nestlings and Were Linked to Gut Microbiota

Great cormorants at a nest on a tree trunk above a lake
Research · Disease, parasites & microbiology

Microplastics were detected in every great cormorant (Phalacrocorax carbo) nestling examined in a 2026 study of wild birds at two early developmental stages. Researchers combined microplastic measurements with 16S rRNA sequencing, a method used to profile the composition of bacterial communities, to investigate whether exposure was associated with the developing gut microbiota.

The researchers examined ten naturally deceased nestlings collected in Longfeng Nature Reserve, Heilongjiang, China, in May and June 2024. Five were at the downy feather stage and five at the emerging pin-feather stage. Samples came from intestinal contents and tissue.

The bacterial communities were dominated by Firmicutes, Proteobacteria and Fusobacteria. Microplastics were measured with laser-direct infrared imaging, allowing the researchers to characterize their abundance, polymer diversity and particle size.

Associations changed with developmental stage

The abundance, diversity and size of microplastic particles were significantly associated with both alpha diversity — the diversity of bacteria within each sample — and the broader composition of the gut microbiota. These relationships differed between the two developmental stages, indicating that the association between microplastics and the microbial community changed as the nestlings developed.

Microplastic concentrations themselves also varied between developmental stages, but that difference was not statistically significant. The study therefore does not support a simple conclusion that one age group contained more microplastics than the other.

Predicted microbial function also depended on developmental stage

The predicted functional profile of the gut microbiota — an estimate of the metabolic and other functions the bacterial community may perform based on its composition — was significantly influenced by developmental stage. The effects associated with microplastics depended on their interaction with developmental stage rather than showing a uniform independent effect across all nestlings.

Graphical overview of microplastics and gut microbiota in great cormorant nestlings
The study’s graphical abstract shows the two developmental stages, microplastics and gut bacteria. DF: downy feather stage; AF: emerging pin-feather stage. Yang et al. (2026), Global Ecology and Conservation. CC BY 4.0.

The authors interpret the results as evidence that environmental microplastic exposure can influence the developing gut microbiota of wild great cormorant nestlings, but they also call for further research to determine the mechanisms involved and whether the observed microbiota changes have long-term consequences for individual health.

Sources and image credit

  1. Yang, T., Xu, P., Chen, L., Yu, B., Meng, L., Wang, H., & Wu, Y. (2026). Microplastics-related alterations of gut microbiota during two early developmental stages in wild great cormorant nestlings (Phalacrocorax carbo). Global Ecology and Conservation, 67, e04175.Longfeng Nature Reserve, China; ten naturally deceased nestlings, sampled May–June 2024.

Image: Sbokil123 / Wikimedia Commons — great cormorants at a nest in Periyar National Park, Kerala, India, 5 November 2015. Representative species image, not the birds sampled in China. Cropped to 16:9. · CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Disease, parasites & microbiology

SPECIES IN THIS STORY

Species in this story

Great Cormorant Phalacrocorax carbo Explore species

Independent research and conservation news archive

Did you find this information useful?

Wildlife Vagabond is independently built and maintained. Voluntary support helps cover source verification, hosting and continued work on research and conservation news.

Support Wildlife Vagabond

The news archive will remain freely available.