Copepod assemblages along a hydrothermal stress gradient at diffuse flow habitats within the ABE vent site (Eastern Lau Spreading Center, Southwest Pacific). (July 2021)

• Record Type: Journal Article
• Authors: Diaz-Recio Lorenzo, Coral; Bruggen, Daisy ter; Luther, George W.; Gartman, Amy; Gollner, Sabine
• Is Part Of: Deep sea research. Volume 173(2021)
• Publication Date: 2021-07
• Subjects: Hydrothermal vents -- Meiofauna -- Copepods -- Deep sea -- Deep sea mining; Oceanography -- Periodicals; Océanographie -- Périodiques; 551.4605
• DOI: 10.1016/j.dsr.2021.103532
• Languages: English
• ISSNs: 0967-0637

Abstract

Abstract: Copepoda is the most diverse and abundant taxon at deep-sea hydrothermal vents, contributing significantly to the biodiversity and thus is important in maintaining ecosystem functioning. To date we lack knowledge on meiofauna, specifically copepod community dynamics, in the entire region of the Eastern Lau Spreading Center. We explore abundance and diversity of copepods associated with foundation species thriving at distinct physiochemical regimes at the active vent site ABE. Diffuse flow habitats within ABE are dominated by three foundation species: (1) the snail Alviniconcha hessleri, exposed to average vent fluid temperatures of ~24 °C, (2) the snail Ifremeria nautilei at ~12 °C, and (3) the mussel Bathymodiolus septemdierum in average temperatures of ~6 °C. In each habitat, three samples were taken using a quantitative collection device (mussel-pot). Copepod abundance ranged from 1 to 30 ind. per 10 cm 2, with no significant differences between the three habitats. A total of 18 copepod species were identified. In the Alviniconcha habitat, the vent endemic dirivultid copepod Stygiopontius lauensis dominated the community, representing >90% of the individuals. Species richness and Shannon diversity were significantly higher in the Bathymodiolus habitat, correlated with lower temperatures, lower hydrogen sulfide concentrations and higher oxygen concentrations. This increase in diversity was driven by a community mostly comprised of habitat generalists including genera reported from shallow coastal waters, shallow vents, and peripheral vent environments. This study provides the first quantification of biodiversity and community structure of copepods along a physiochemical stress gradient at a relatively stable Southwest Pacific vent site prospective for deep-sea mining. Highlights: Copepod communities at the ABE vent field are unique. Three vent-endemic dirivultid species dominate in mid-high H2 S/HS- concentrations. Species richness is significantly higher in mid-low H2 S/HS- concentrations. Harpacticoid copepods are common in mid-low H2 S/HS- concentrations. This study provides biodiversity data, helping inform mining policy at ABE.