Schmidt Katrin, Niehoff Barbara, Cornils Astrid, Hagen Wilhelm, Flores Hauke, Heuzé Céline, Welteke Nahid, Knϋppel Nadine, Dorschner Sabrina, Woll Matthias, Jones Katie, Laudone Giuliano, Campbell Robert G, Ashjian Carin J, Gelfman Cecilia E, Shoemaker Katyanne M, Jenkins Rebecca, Kvile Kristina Øie, Lebreton Benoit, Guillou Gaël, Hoppe Clara J M, Sakinan Serdar, Schaafsma Fokje L, Hildebrandt Nicole, Castellani Giulia, Belt Simon T, Fong Allison A, Atkinson Angus, Graeve Martin
School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK.
Alfred Wegener Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany.
Commun Earth Environ. 2025;6(1):431. doi: 10.1038/s43247-025-02389-9. Epub 2025 Jun 4.
Seasonal vertical migration of large lipid-rich copepods is often described as a mass descent of animals when primary production ceases, with important implications for mesopelagic food webs and global carbon sequestration. This view ignores the existence of surface-resident individuals, but here we show that non-migrants can form a substantial part of the populations of polar migrant species. In the Central Arctic Ocean, the biomass-dominant was evenly distributed throughout the water column from November 2019 to March 2020, with ~20% of subadults and adult females remaining in the upper 200 m and ~41% migrating to 1000-2000 m. These vertical positions aligned with differences in the copepods' cholesterol content, which can enhance the tissue density at higher temperatures. Gonad development and the vertical distribution of their offspring indicate that both non-migrant and migrant females contribute to the population recruitment. We reinterpret copepod seasonal migration as a bet-hedging strategy that balances nutritional benefits near the surface with survival benefits at depth, and thereby contributes to the species' resilience under climatic change.
富含脂质的大型桡足类动物的季节性垂直迁移通常被描述为在初级生产停止时动物的大规模下沉，这对中层食物网和全球碳固存具有重要影响。这种观点忽略了表层定居个体的存在，但我们在此表明，非迁移个体可构成极地迁移物种种群的很大一部分。在北冰洋中部，从2019年11月到2020年3月，生物量占主导的桡足类动物在整个水柱中均匀分布，约20%的亚成体和成年雌性留在上层200米处，约41%迁移到1000 - 2000米深处。这些垂直位置与桡足类动物胆固醇含量的差异一致，胆固醇可在较高温度下提高组织密度。性腺发育及其后代的垂直分布表明，非迁移和迁移的雌性都对种群补充有贡献。我们将桡足类动物季节性迁移重新解释为一种风险对冲策略，该策略平衡了表层附近的营养益处和深处的生存益处，从而有助于该物种在气候变化下的恢复力。
