Insights on long-term ecosystem changes from stable isotopes in historical squid beaks

Area of Science:

• Marine ecology
• Climate change research
• Stable isotope analysis

Background:

• Arctic marine ecosystems face climate change impacts.
• Traditional proxies (top predators) may not fully capture ecosystem shifts.
• Retrospective studies on short-living mesopredators are lacking.

Purpose of the Study:

• To assess if climate-driven ecosystem shifts are detectable in short-living mesopredators.
• To analyze ontogenetic changes in stable isotope signatures of Arctic squids.
• To use squids as proxies for retrospective ecological studies.

Main Methods:

• Stable isotope analysis of chitinous hard body structures.
• Analysis of two abundant squid species (Gonatus fabricii and Todarodes sagittatus).
• Study of specimens collected between 1844 and 2023.

Main Results:

• Gonatus fabricii exhibited increased diet generalism, trophic position, and niche width.
• Observed shifts in G. fabricii correlate with Arctic "Atlantification" and increased primary production.
• Todarodes sagittatus showed a more generalist diet in recent times compared to the 19th century.

Conclusions:

• Abundant, short-lived mesopredators like squids are effective indicators of climate-driven ecosystem shifts.
• Squid diet generalism and niche width reflect Arctic food web generalization.
• Squids' adaptability suggests they may benefit from short-term Arctic ecosystem changes.