Does substrate matter in the deep sea? A comparison of bone, wood, and carbonate rock colonizers

Abstract

Continental margins host methane seeps, animal falls and wood falls, with chemosynthetic communities that may share or exchange species. The goal of this study was to examine the existence and nature of linkages among chemosynthesis-based ecosystems by deploying organic fall mimics (bone and wood) alongside defaunated carbonate rocks within high and lesser levels of seepage activity for 7.4 years. We compared community composition, density, and trophic structure of invertebrates on these hard substrates at active methane seepage and transition (less seepage) sites at Mound 12 at ~1,000 m depth, a methane seep off the Pacific coast of Costa Rica. At transition sites, the community composition on wood and bone was characteristic of natural wood- and whale-fall community composition, which rely on decay of the organic substrates. However, at active sites, seepage activity modified the relationship between fauna and substrate, seepage activity had a stronger effect in defining and homogenizing these communities and they depend less on organic decay. In contrast to community structure, macrofaunal trophic niche overlap between substrates, based on standard ellipse areas, was greater at transition sites than at active sites, except between rock and wood. Our observations suggest that whale- and wood-fall substrates can function as stepping stones for seep fauna even at later successional stages, providing hard substrate for attachment and chemosynthetic food.

Invertebrate trophic structure on marine ferromanganese and phosphorite hardgrounds

“…Trophic diversity was calculated as δ 13 C and δ 15 N total hull areas in this same bivariate space, and species packing was determined through measurement of the mean distance to the centroid and mean nearest neighbor distance. Pairwise ellipse overlaps based on Bayesian posterior estimates were calculated using 2 chains of 20,000 iterations with a burn‐in of 1000 and thinning of 10 (Pereira et al 2022) to examine whether animals are utilizing the same food sources on different rock types, proximity to shore, and OMZ categories.…”

“…Community-level metrics (Layman et al 2007) were calculated using Stable Isotope Bayesian Ellipses in R (SIBER) package (Jackson et al 2011), following Pereira et al (2021Pereira et al ( , 2022, to examine the trophic structure of the megafaunal and macrofaunal communities on different rock types, proximity to shore, and OMZ categories. Source and variability of primary production at the base of the food chain was identified through δ 13 C values and ranges.…”

Cutting the ribbon: bathyal Nemertea from seeps along the Costa Rica margin, with descriptions of 2 new genera and 9 new species

“…This species was collected on naturally occurring and experimentally deployed wood (Pereira et al 2022), including the same deployment associated with a paratype of the scaleworm Peinaleopolynoe elvisi Hatch & Rouse in Hatch, Liew, Hourdez & Rouse, 2020(MZUCR 1000.…”

Sunken trees in the deep sea link terrestrial and marine biodiversity

“…Although research has revealed much about individual taxa, especially xylophagous bivalves, inhabiting deep‐sea wood falls, much less is known about the alpha‐ or beta‐diversity of entire wood‐fall communities, host specificity, or the wooden drivers of each (Judge & Barry, 2016; McClain et al, 2016; McClain & Barry, 2014; McClain, Barry, & Webb, 2018; McClain, Nunnally, et al, 2018; Pereira, Gonzalez, et al, 2022; Voight, 2007; Young et al, 2022) that could potentially elucidate terrestrial anthropogenic impacts would impact deep‐sea wood‐fall communities. On land, dead wood‐inhabiting communities are impacted by time through successional processes and wood decay, wood size through resource and space availability, and tree species through host specificity and niche filtering (Andringa et al, 2019; Müller et al, 2020; Seibold et al, 2015; Ulyshen & Hanula, 2009; Zuo et al, 2021).…”