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Abstract Due to historical under‐sampling of the deep ocean, the distributional ranges of mesopelagic zooplankton are not well documented, leading to uncertainty about the mechanisms that shape midwater zooplankton community composition. Using a combination of DNA metabarcoding (18S‐V4 and mtCOI) and trait‐based analysis, we characterized zooplankton diversity and community composition in the upper 1000 m of the northeast Pacific Ocean. We tested whether the North Pacific Transition Zone is a biogeographic boundary region for mesopelagic zooplankton. We also tested whether zooplankton taxa occupying different vertical habitats and exhibiting different ecological traits differed in the ranges of temperature, Chl‐a, and dissolved oxygen conditions inhabited. The depth of the maximum taxonomic richness deepened with increasing latitude in the North Pacific. Community similarity in the mesopelagic zone also increased in comparison with the epipelagic zone, and no evidence was found for a biogeographic boundary between previously delineated mesopelagic biogeochemical provinces. Epipelagic zooplankton exhibited broader temperature and Chl‐aranges than mesopelagic taxa. Within the epipelagic, taxa with broader temperature and Chl‐aranges also had broader distributional ranges. However, mesopelagic taxa were distributed across wider dissolved oxygen ranges, and within the mesopelagic, only oxygen ranges covaried with distributional ranges. Environmental and distributional ranges also varied among traits, both for epipelagic taxa and mesopelagic taxa. The strongest differences in both environmental and distributional ranges were observed for taxa with or without diel vertical migration behavior. Our results suggest that species traits can influence the differential effects of physical dispersal and environmental selection in shaping biogeographic distributions.
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This content will become publicly available on December 19, 2026
Influences of Dispersal and Environmental Selection on Zooplankton Distributions Across the Upper 1000 m of the North Pacific
ABSTRACT AimTest the response of mesopelagic zooplankton community composition and distributional ranges to dispersal potential and environment, in comparison with the epipelagic zooplankton community. LocationEpipelagic (0–200 m) and mesopelagic (200–1000 m) depth zones of the North Pacific Ocean. TaxonMulticellular zooplankton. MethodsMetabarcoding of two molecular markers (18S and COI) in combination with a global ocean circulation model, analysed by General Dissimilarity Modelling. ResultsWe found no significant difference in beta‐diversity across three depth strata (0–200, 200–500, and 500–1000 m), calculated from the nMDS dispersion of samples within each stratum. Similarity in beta‐diversity within the three depth strata indicates that epipelagic and mesopelagic zooplankton communities have similar levels of spatial turnover in species composition despite differences in the magnitude of environmental gradients and dispersal potential. There were no differences in the biogeographic ranges of taxa associated with each depth zone, but we observed larger temperature, salinity, and dissolved oxygen habitat envelopes as well as narrower potential food ranges for deeper‐dwelling taxa. Ocean basin‐scale community dissimilarity was correlated with dispersal distance, as well as with changes in temperature, salinity, dissolved oxygen concentration, and food flux. Combined Generalised Dissimilarity Models incorporating both dispersal potential and environmental habitat variables revealed that the environmental variables temperature and food flux had the strongest predictive power to explain community dissimilarity.
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- Award ID(s):
- 1948162
- PAR ID:
- 10655939
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Biogeography
- ISSN:
- 0305-0270
- Subject(s) / Keyword(s):
- biogeography community composition connectivity dispersal epipelagic mesopelagic selection zooplankton
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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