Consistency and Variation in the Kelp Microbiota: Patterns of Bacterial Community Structure Across Spatial Scales

Abstract

Kelp species are distributed along ~25% of the world's coastlines and the forests they form represent some of the world's most productive and diverse ecosystems. Like other marine habitat-formers, the associated microbial community is fundamental for host and, in turn, wider ecosystem functioning. Given there are thousands of bacteria-host associations, determining which relationships are important remains a major challenge. We characterised the associated bacteria of two habitat-forming kelp species, Laminaria hyperborea and Saccharina latissima, from eight sites across a range of spatial scales (10s of metres to 100s of km) in the northeast Atlantic. We found no difference in diversity or community structure between the two kelps but there was evidence of regional structuring (across 100s km) and considerable variation between individuals (10s of metres). Within sites, individuals shared few Amplicon Sequence Variants (ASVs) and supported a very small proportion of diversity found across the wider study area. However, consistent characteristics between individuals were observed with individual host communities containing a small conserved "core" (8-11 ASVs comprising 25 and 32% of sample abundances for L. hyperborea and S. latissima, respectively). At a coarser taxonomic resolution, communities were dominated by four classes (Planctomycetes, Gammaproteobacteria, Alphaproteobacteria and Bacteroidia) that made up ~84 % of sample abundances. Remaining taxa (47 classes) made up very little contribution to overall abundance but the majority of taxonomic diversity. Overall, our study demonstrates the consistent features of kelp bacterial communities across large spatial scales and environmental gradients and provides an ecologically meaningful baseline to track environmental change.

The Saccharina latissima microbiome: Effects of region, season, and physiology

“…Those taxa were also found on the meristem part of L. digitata (Ihua et al, 2020) and on the blade of L. setchellii (Lemay et al, 2021), Taonia atomaria (Paix et al, 2021), and U. lactuca (Comba González et al, 2021). Our results are furthermore consistent with the core microbiota found in S. latissima and L. hyperborea in the United Kingdom (King et al, 2022). Granulosicoccus sp.…”

The Saccharina latissima microbiome: algal tissue matters more than region, season, and physiology

“…lactuca (Comba González et al, 2021). Our results are furthermore consistent with the core microbiota found in S. latissima and L. hyperborea in the United Kingdom (King et al, 2022).…”

Alternative approaches to identify core bacteria in Fucus distichus microbiome and assess their distribution and host-specificity

“…Yet, within this variability a suite of taxa frequently found on macroalgal surfaces is emerging across studies, including Saprospiraceae, Granulosicoccus, and Flavobacteria [34][35][36]. Earlier studies reported a handful of core bacterial taxa consistently associated with particular populations in a few macroalgal species, including Kelp [37], Agarophyton vermiculophyllum [38], Fucus vesiculosus [28], Ulva australis [39] and Ascophyllum nodosum [40]. However, these studies were limited in scope, focusing on one location at one point in time, often without corresponding sampling of the macroalgae' environment.…”