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Marine zooplankton are rapid-responders and useful indicators of environmental variability and climate change impacts on pelagic ecosystems on time scales ranging from seasons to years to decades. The systematic complexity and taxonomic diversity of the zooplankton assemblage has presented significant challenges for routine morphological (microscopic) identification of species in samples collected during ecosystem monitoring and fisheries management surveys. Metabarcoding using the mitochondrial Cytochrome Oxidase I (COI) gene region has shown promise for detecting and identifying species of some – but not all – taxonomic groups in samples of marine zooplankton. This study examined species diversity of zooplankton on the Northwest Atlantic Continental Shelf using 27 samples collected in 2002-2012 from the Gulf of Maine, Georges Bank, and Mid-Atlantic Bight during Ecosystem Monitoring (EcoMon) Surveys by the NOAA NMFS Northeast Fisheries Science Center. COI metabarcodes were identified using the MetaZooGene Barcode Atlas and Database ( https://metazoogene.org/MZGdb ) specific to the North Atlantic Ocean. A total of 181 species across 23 taxonomic groups were detected, including a number of sibling and cryptic species that were not discriminated by morphological taxonomic analysis of EcoMon samples. In all, 67 species of 15 taxonomic groups had ≥ 50 COI sequences; 23 species had >1,000 COI sequences. Comparative analysis of molecular and morphological data showed significant correlations between COI sequence numbers and microscopic counts for 5 of 6 taxonomic groups and for 5 of 7 species with >1,000 COI sequences for which both types of data were available. Multivariate statistical analysis showed clustering of samples within each region based on both COI sequence numbers and EcoMon counts, although differences among the three regions were not statistically significant. The results demonstrate the power and potential of COI metabarcoding for identification of species of metazoan zooplankton in the context of ecosystem monitoring.
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Population connectivity of the euphausiid, Stylocheiron elongatum , in the Gulf Stream (NW Atlantic Ocean) in relation to COI barcode diversity of Stylocheiron species
Abstract The euphausiid genus Stylocheiron includes species with biogeographical distributions spanning multiple ocean basins. Despite their circumglobal distributions, the species show low levels of genetic diversity and little or no evidence of population structure based on the mitochondrial cytochrome oxidase I (COI) barcode region, with the exception of a possible cryptic species within Stylocheiron affine. Stylocheiron elongatum showed < 1% variation of the COI barcode region among populations in different ocean basins, but analysis of samples collected from the Florida Current (February, 1993) and Gulf Stream Meander Region (April, 1993) in the Northwest Atlantic Ocean revealed small-but-significant genetic differentiation between samples based on a different section of COI and mitochondrial cytochrome b (CYB). Both COI and CYB showed large haplotype and small nucleotide diversities, departures from neutral expectations, and haplotype networks consistent with persistent genetic structuring of the species population. These patterns of diversity indicate the presence of selection driving population divergence. We hypothesize that position-keeping by this deep-living, non-migrating euphausiid species may prevent genetic homogenization (panmixia) in the dynamic Gulf Stream System. This study demonstrates the importance of analyzing patterns of genetic diversity and structure at regional and global scales to understand the ecological and evolutionary processes impacting marine zooplankton.
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- Award ID(s):
- 1840868
- PAR ID:
- 10443592
- Editor(s):
- Grant, William
- Date Published:
- Journal Name:
- ICES Journal of Marine Science
- Volume:
- 78
- Issue:
- 9
- ISSN:
- 1054-3139
- Page Range / eLocation ID:
- 3464 to 3476
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1093/icesjms/fsab158
