Differences in the trophic ecology of micronekton driven by diel vertical migration. (4th February 2019)

• Record Type: Journal Article
• Authors: Romero‐Romero, Sonia; Choy, C. Anela; Hannides, Cecelia C. S.; Popp, Brian N.; Drazen, Jeffrey C.
• Is Part Of: Limnology and oceanography. Volume 64:Number 4(2019)
• Page Start: 1473
• Page End: 1483
• Publication Date: 2019-02-04
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; Océanographie; Limnologie; Limnology; Oceanography; Computer network resources; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); Periodicals; 551.4805
• DOI: 10.1002/lno.11128
• Languages: English
• ISSNs: 0024-3590

Abstract

Abstract: Many species of micronekton perform diel vertical migrations (DVMs), which ultimately contributes to carbon export to the deep sea. However, not all micronekton species perform DVM, and the nonmigrators, which are often understudied, have different energetic requirements that might be reflected in their trophic ecology. We analyze bulk tissue and whole animal stable nitrogen isotopic compositions ( δ 15 N values) of micronekton species collected seasonally between 0 and 1250 m depth to explore differences in the trophic ecology of vertically migrating and nonmigrating micronekton in the central North Pacific. Nonmigrating species exhibit depth‐related increases in δ 15 N values mirroring their main prey, zooplankton. Higher variance in δ 15 N values of bathypelagic species points to the increasing reliance of deeper dwelling micronekton on microbially reworked, very small suspended particles. Migrators have higher δ 15 N values than nonmigrators inhabiting the epipelagic zone, suggesting the consumption of material during the day at depth, not only at night when they migrate closer to the surface. Migrating species also appear to eat larger prey and exhibit a higher range of variation in δ 15 N values seasonally than nonmigrators, likely because of their higher energy needs. The dependence on material at depth enriched in 15 N relative to surface particles is higher in migratory fish that ascend only to the lower epipelagic zone. Our results confirm that stark differences in the food habits and dietary sources of micronekton species are driven by vertical migrations.