Ecological dispersal barrier across the equatorial Atlantic in a migratory planktonic copepod. (November 2017)

• Record Type: Journal Article
• Authors: Goetze, Erica; Hüdepohl, Patricia T.; Chang, Chantel; Van Woudenberg, Lauren; Iacchei, Matthew; Peijnenburg, Katja T.C.A.
• Is Part Of: Progress in oceanography. Volume 158(2017:Nov.)
• Page Start: 203
• Page End: 212
• Publication Date: 2017-11
• Subjects: Pleuromamma xiphias -- Population genetic structure -- Mitochondrial COI -- Atlantic Meridional Transect Programme (AMT); Oceanography -- Periodicals; 551.4605
• DOI: 10.1016/j.pocean.2016.07.001
• Languages: English
• ISSNs: 0079-6611

Abstract

Highlights: Strong population genetic structure occurred within P. xiphias across the Atlantic. The equatorial Atlantic is a region of strong genetic transition and low abundance. One mtCOI clade and several haplotypes were endemic to the equatorial region. The equatorial Atlantic is an important dispersal barrier for the holoplankton. Abstract: Resolving the large-scale genetic structure of plankton populations is important to understanding their responses to climate change. However, few studies have reported on the presence and geographic extent of genetically distinct populations of marine zooplankton at ocean-basin scales. Using mitochondrial sequence data (mtCOI, 718 animals) from 18 sites across a basin-scale Atlantic transect (39°N–40°S), we show that populations of the dominant migratory copepod, Pleuromamma xiphias, are genetically subdivided across subtropical and tropical waters (global F ST = 0.15, global ΦST = 0.21, both P < 0.00001), with a major genetic break observed in the equatorial Atlantic (between gyre F CT and ΦCT = 0.23, P < 0.005). This equatorial region of strong genetic transition coincides with an area of low abundance for the species. Transitional regions between the subtropical gyres and the equatorial province also harbor a distinct mitochondrial clade (clade 2), have higher haplotype and nucleotide diversities relative to the northern and/or southern subtropical gyres (e.g., mean h = 0.831 EQ, 0.742 North, 0.594 South, F 2, 11 = 20.53, P < 0.001), and are genetically differentiated from the majority of sites in the central gyre and temperate zones of the same hemisphere (significant pairwise ΦST 0.038–0.267, 79% significant). Our observations support the hypothesis that regions of low abundance within species mark areas of suboptimal habitat that serve as dispersal barriers for marine plankton, and we suggest that this may be a dominant mechanism driving the large-scale genetic structure of zooplankton species. Our results also demonstrate the potential importance of the Atlantic equatorial province as a region of evolutionary novelty for the holoplankton.