Recovery of hydrothermal vent communities in response to an induced disturbance at the Lucky Strike vent field (Mid-Atlantic Ridge)

Abstract

So far, the natural recovery of vent communities at large scales has only been evaluated at fast spreading centres, by monitoring faunal recolonisation after volcanic eruptions. However, at slow spreading ridges, opportunities to observe natural disturbances are rare, the overall hydrothermal system being more stable. In this study, we implemented a novel experimental approach by inducing a small-scale disturbance to assess the recovery potential of vent communities along the slow-spreading northern Mid-Atlantic Ridge (nMAR). We followed the recovery patterns of thirteen Bathymodiolus azoricus mussel assemblages colonising an active vent edifice at the Lucky Strike vent field, in relation to environmental conditions and assessed the role of biotic interactions in recolonisation dynamics. Within 2 years after the disturbance, almost all taxonomic richness had recovered, with the exception of a few low occurrence species. However, we observed only a partial recovery of faunal densities and a major change in faunal composition characterised by an increase in abundance of gastropod species, which are hypothesised to be the pioneer colonists of these habitats. Although not significant, our results suggest a potential role of mobile predators in early-colonisation stages. A model of post-disturbance succession for nMAR vent communities from habitat opening to climax assemblages is proposed, also highlighting numerous knowledge gaps. This type of experimental approach, combined with dispersal and connectivity analyses, will contribute to fully assess the resilience of active vent communities after a major disturbance, especially along slow spreading centres targeted for seafloor massive sulphide extraction.

Northern Mid-Atlantic Ridge Hydrothermal Habitats: A Systematic Review of Knowledge Status for Environmental Management

“…Based on physical and genetic studies, the recolonisation of disturbed sites by Bathymodiolus mussels (foundation species where they are present on the MAR) is only expected to occur by chance (Breusing et al, 2017), indicating that populations of these species have a low resilience to impact. A recent small scale disturbance experiment assessing recovery after an artificial disturbance inside the Lucky Strike hydrothermal vent field demonstrated that after 2 years there was a major change in faunal composition, only a partial recovery of faunal densities, and that the species composition of the neighbouring faunal assemblages strongly affects the species composition of the recolonising community (Marticorena et al, 2021).…”

“…Apart from a recent small-scale disturbance experiment conducted in the Lucky Strike vent field (Marticorena et al, 2021), dedicated resilience and recovery studies have not been conducted for the biological communities colonising hydrothermally active habitats or inactive sulphide habitats on the nMAR. The results from the study by Marticorena et al (2021) demonstrated the complexity of recovery patterns in response to even small-scale disturbances on the nMAR, highlighting the importance of prior information on connectivity and temporal patterns to fully understand recovery processes after a major disturbance.…”

Integrating Multidisciplinary Observations in Vent Environments (IMOVE): Decadal Progress in Deep-Sea Observatories at Hydrothermal Vents

“…Extensive experiments conducted during maintenance cruises (e.g., Cannat and Sarradin, 2010) have produced key insights into the biodiversity, functional diversity, and ecology of MAR hydrothermal communities. These include (re-) colonization processes and relationships between vent and cognate communities along a vent gradient and on different types of substrata (Cuvelier et al, 2014a;Zeppilli et al, 2015;Plum et al, 2016;Baldrighi et al, 2018;Alfaro-Lucas et al, 2020;Cowart et al, 2020;Marticorena et al, 2021). Biological samples have contributed to increasing basic knowledge of species biology (Husson et al, 2017;Marticorena et al, 2020), trophic interactions (Lelièvre et al, 2018;Portail et al, 2018;Zeppilli et al, 2019), biological rhythms (Mat et al, 2020) and physiology (Husson et al, 2018), leading to a growing understand of vent faunal functional traits (Chapman et al, 2019;Alfaro-Lucas et al, 2020;Murdock et al, 2021).…”

Integrated Study of New Faunal Assemblages Dominated by Gastropods at Three Vent Fields Along the Mid-Atlantic Ridge: Diversity, Structure, Composition and Trophic Interactions

“…Indeed, temperatures can display variations of up to 20°C within a few centimeters in response to turbulence, mixing and biological processes (Le Lee et al, 2015). Similarly, a recent study showed that temperature values obtained by probes deployed directly on the substratum were significantly higher than those obtained with the submersible sensor few centimeters above the fauna (Marticorena et al, 2021). This difference questions once again the use of single-point temperature measurements to define the niche of vent species.…”

“…A recent study in LS showed the importance of gastropods early in the recolonization processes following a disturbance (Marticorena et al, 2021). They might take advantage of the microbial films forming on "bare" substratum early in the succession process (Sarrazin et al, 1997;Mullineaux et al, 2010;Mullineaux et al, 2012).…”