DNA Analysis Shows Diverse Diets of Arctic Seabirds

Jenn Hoskins
7th July, 2024

DNA Analysis Shows Diverse Diets of Arctic Seabirds

Image Source: Natural Science News, 2024

Key Findings

  • The study by Wageningen University used DNA-metabarcoding on seabird faeces to analyze diets with minimal disturbance
  • This method identified a wider variety of fish and crustaceans in seabird diets compared to traditional techniques
  • DNA-metabarcoding proved to be a cost-effective and less invasive tool for monitoring Arctic seabird diets and environmental changes
Climate change poses a significant threat to Arctic marine ecosystems, impacting food webs and the species that depend on them. To understand these changes, researchers have focused on the diet shifts of seabirds, which serve as indicators of environmental changes, including species compositions in food webs. Traditional methods of studying seabird diets are often invasive, labor-intensive, and costly. However, DNA-metabarcoding techniques offer a promising alternative for monitoring diet choices with minimal disturbance to wildlife and the environment. A recent study conducted by Wageningen University tested the efficacy of DNA-metabarcoding on seabird faeces collected during short visits to breeding colonies of black-legged kittiwake (Rissa tridactyla), Brünnich’s guillemot (Uria lomvia), and little auk (Alle alle)[1]. This method revealed a wide spectrum of fish species and crustaceans in the diets of these seabirds, surpassing the diversity found using conventional techniques. The study highlights the potential of DNA-metabarcoding as a cost-effective and less invasive tool for monitoring Arctic seabird diets and understanding the broader impacts of environmental changes on marine ecosystems. The study involved collecting faeces samples during brief visits of approximately 30 minutes to seabird colonies. DNA-metabarcoding based on COI and 18S genes was performed on these samples, revealing a rich diversity of diet components. Notably, the technique identified a variety of pelagic and benthic fish species in the diet of little auks, a crustacean specialist, which had previously been underreported using traditional methods. The findings align with earlier research on the impact of environmental changes on Arctic seabirds. For instance, a 12-year study on little auks demonstrated their substantial plasticity in response to sea-ice concentration (SIC) changes, including adjustments in foraging behavior and diet composition[2]. The study found that decreased SIC led to less lipid-rich prey in their diet, negatively affecting adult body condition and chick growth rates. Additionally, mercury contamination was linked to these adverse effects. The new DNA-metabarcoding study complements these findings by providing a more detailed understanding of the diet diversity and potential shifts in response to environmental changes. Further, research on Calanus species, which are crucial components of the Arctic food web, has shown that accurate identification of these species is essential for understanding their role in seabird diets[3]. Genetic identification revealed that a significant portion of Calanus individuals were misclassified based on morphology alone. The diet of little auks was found to consist almost entirely of C. glacialis, even in regions with varying levels of Atlantification. This suggests that the observed shifts in diet composition may be more related to the size reduction of C. glacialis rather than a species shift to C. finmarchicus. The new DNA-metabarcoding approach can enhance the accuracy of such dietary studies by reducing identification biases. Additionally, the study on black-legged kittiwakes from Svalbard indicated that various environmental contaminants could disrupt metabolic rates through their thyroid hormone-disrupting properties[4]. This disruption could affect energy expenditure and, consequently, the foraging efficiency and diet composition of seabirds. The DNA-metabarcoding study's ability to provide detailed dietary information can help in understanding how such contaminants might indirectly influence seabird diets by affecting their metabolic rates and foraging behaviors. In conclusion, the DNA-metabarcoding study by Wageningen University demonstrates the technique's effectiveness in revealing a comprehensive and detailed picture of seabird diets with minimal disturbance to the birds and their environment. This method can significantly enhance our understanding of Arctic marine food webs and the impacts of climate change and pollution on these ecosystems. By integrating findings from previous studies on seabird foraging ecology, contaminant effects, and species identification, the new study offers a robust tool for monitoring and conserving Arctic marine biodiversity.

GeneticsAnimal ScienceMarine Biology

References

Main Study

1) DNA metabarcoding reveals high diversity of fish and macrofaunal species in diets of little auks and other Arctic seabird species in Svalbard

Published 6th July, 2024

https://doi.org/10.1007/s00300-024-03276-3


Related Studies

2) Arctic climate change and pollution impact little auk foraging and fitness across a decade.

https://doi.org/10.1038/s41598-018-38042-z


3) Molecular tools prove little auks from Svalbard are extremely selective for Calanus glacialis even when exposed to Atlantification.

https://doi.org/10.1038/s41598-023-40131-7


4) Contaminants and energy expenditure in an Arctic seabird: Organochlorine pesticides and perfluoroalkyl substances are associated with metabolic rate in a contrasted manner.

https://doi.org/10.1016/j.envres.2017.05.022



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