Deep-sea shipwrecks represent island-like ecosystems for marine microbiomes

Abstract

Biogeography of macro- and micro-organisms in the deep sea is, in part, shaped by naturally occurring heterogeneous habitat features of geological and biological origin such as seeps, vents, seamounts, whale and wood-falls. Artificial features including shipwrecks and energy infrastructure shape the biogeographic patterns of macro-organisms; how they influence microorganisms is unclear. Shipwrecks may function as islands of biodiversity for microbiomes, creating a patchwork of habitats with influence radiating out into the seabed. Here we show microbiome richness and diversity increase as a function of proximity to the historic deep-sea shipwreck Anona in the Gulf of Mexico. Diversity and richness extinction plots provide evidence of an island effect on microbiomes. A halo of core taxa on the seabed was observed up to 200 m away from the wreck indicative of the transition zone from shipwreck habitat to the surrounding environment. Transition zones around natural habitat features are often small in area compared to what was observed at Anona indicating shipwrecks may exert a large sphere of influence on seabed microbiomes. Historic shipwrecks are abundant, isolated habitats with global distribution, providing a means to explore contemporary processes shaping biogeography on the seafloor. This work is a case study for how built environments impact microbial biodiversity and provides new information on how arrival of material to the seafloor shapes benthic microbiomes.

Deep‐sea wooden shipwrecks influence sediment microbiome diversity

“…The extent of influence of this shipwreck is comparable with that observed for organic falls (Smith et al 2015). It is possible the shipwreck's influence on the surrounding seabed goes beyond the area examined in this study, based on observations of larger shipwrecks and their microbiomes (Hamdan et al 2021). We note, however, the size and age of sites in the current study are smaller and older, respectively, than previously investigated locations.…”

“…These results are intriguing given that many organic fall studies (Goffredi and Orphan 2010;Fagervold et al 2012) and previous shipwreck studies (Hamdan et al 2018(Hamdan et al , 2021 report increased bacterial diversity with increasing proximity to features. Hamdan et al (2021) reported increased bacterial diversity, and richness surrounding a larger steel-hulled historic shipwreck that extended up to 200 m on the seafloor. In that study, the relationship of proximity and diversity was nonlinear, and instead step-like at intermediate distances.…”

“…In the deep sea, microbial life relies on the biological carbon pump, sinking organic matter (OM) from the euphotic zone, or chemolithotrophy (Zinger et al 2011; Bienhold et al 2013). Natural (reefs, hydrothermal vents, cold seeps) and artificial features on the seabed alter the local environment, biogeochemistry, microbial community composition and diversity (Zinger et al 2011; Bienhold et al 2013; Hamdan et al 2021). To date, the majority of microbial ecology studies in marine sediments have focused on geological features such as hydrothermal vents and hydrocarbon seeps, which are considered hotspots of biological activity and diversity (Orcutt et al 2011; Anderson et al 2015; Ruff et al 2015) and select for phylogenetically distinct microbial communities (Dick 2019) and metabolic pathways (Dombrowski et al 2018).…”

“…Although many microbiome studies have focused on natural features on the seabed, built environments (e.g., artificial reefs, shipwrecks, oil, and gas infrastructures) are frequently overlooked. Historic shipwrecks (> 50 years old) can be viewed as islands of microbial biodiversity, similar to natural seafloor features (Hamdan et al 2018(Hamdan et al , 2021. They provide food, refuge from predation, hard substrate for microbial colonization, and assist in dispersal and recruitment of microorganisms and macrofauna (Walker et al 2007;Hamdan et al 2018;Mugge et al 2019).…”

“…Moreover, some built environments are composed of materials not naturally occurring on the seabed (metal, plastic, composites;Mugge et al 2019). Large, metal-hulled shipwreck isolated on seabed influenced sediment microbiome diversity and richness, resulting in an increase in both with proximity and extending outward 200 m onto the seabed (Hamdan et al 2021). The size and composition of these halos of biodiversity are dictated by the time since shipwreck arrival on seabed, since their increase in size may be in response to hull degradation and resource utilization (Stieglitz 2013;Reeds et al 2018), along with physical alterations of sediment resulting from the presence of a high relief (> 1 m) structure (Harris 2014).…”