Community succession in hydrothermal vent habitats of the Eastern Lau Spreading Center and Valu Fa Ridge, Tonga

Abstract

Patterns of succession in Lau Basin hydrothermal vent communities determined with high-resolution imagery and in situ physico-chemical data collected over 4 yr and analyzed within a Geographic Information System show that Alviniconcha snails are a pioneering group, the snail Ifremeria nautilei is a mid-successional species, and the heat-intolerant mussel Bathymodiolus brevior dominates when venting declines. The associated fauna also changes as communities progress through the successional stages, and eventually non-vent-endemic deepsea species appear when venting has mostly subsided. This is a unique example of primary succession in which the primary producers form symbiotic associations with mobile animals, resulting in successional patterns not observed in other systems. I. nautilei dominates newly formed substrates or venting sources where both I. nautilei and Alviniconcha spp. are already established (e.g., by migration), while Alviniconcha spp. seem to be better at colonizing newly active vents (e.g., by settlement) that are remote from colonized vents. Thus, on the scale of a 5-39 m 2 diffuse flow area or a single edifice, the mid-successional species dominates new substrates instead of the pioneering group. These communities are remarkably stable over long time periods relative to other hydrothermal vent regions. In addition to the sequential replacements of species as sites age and overall conditions change, Lau vent animals track changes in vent fluids and relocate themselves when local hydrothermal plumbing changes over small spatial scales.

Long-Term Stability of Back-Arc Basin Hydrothermal Vents

“…We imaged the edifices with a forward-mounted camera and made spatially explicit in situ thermal measurements using a temperature probe and the ROV manipulators. Details on the hardware used before 2016 are available in Podowski et al (2010) and Sen et al (2014). During the 2016 expedition, we used an add-on 18-megapixel Canon EOS Rebel T5i digital still camera with a 20 mm Canon lens and the ROPOS high-temperature probe.…”

“…Long-term time-series have been achieved at only a handful of the better-known sites, the majority of which are on medium to fast spreading rate mid-ocean ridges (≥55 mm·year −1 ), such as the Galapagos Rift, the East Pacific Rise, and the Juan de Fuca Ridge (Glover et al, 2010;Beaulieu, 2015). Based on these studies, hydrothermal vents are widely considered to be dynamic, ephemeral habitats (Goldfarb et al, 1983;Chevaldonné et al, 1991;Haymon et al, 1993;Sarrazin et al, 1997;Tunnicliffe et al, 1997;Shank et al, 1998;Johnson et al, 2000;Mullineaux et al, 2003;Cowen et al, 2007;Sen et al, 2014). However, the long-term natural variability of back-arc basin hydrothermal vents is largely unstudied (Boschen et al, 2013;Levin et al, 2016).…”

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

“…At Juan de Fuca Ridge, directed changes in community composition from polychaetes (Paralvinella sulfincola and P. palmiformis) to limpets (Lepetodrilus fucensis) to tubeworms (Ridgeia piscesae) over 4 years were related to both changes in fluid flow and associated interactions, appearing to follow a dynamic succession model that allows reversal with changes in fluid flow (Sarrazin et al, 1997). Non-vent endemic deep-sea species appeared in patches where venting subsided (Podowski et al, 2010;Sen et al, 2014).…”

Rapid colonisation by nematodes on organic and inorganic substrata deployed at the deep-sea Lucky Strike hydrothermal vent field (Mid-Atlantic Ridge)

“…While succession of large animals at vents is relatively well observed (Sen et al 2014), we know much less on the associated meiofauna and, in particular, on nematodes (Gollner et al 2013). A study on mussel beds of different ages (4 to >20 years) showed that nematodes were less abundant and diverse at younger sites (Copley et al 2007).…”