Epibacterial community patterns on marine macroalgae are host‐specific but temporally variable

Abstract

Marine macroalgae are constantly exposed to epibacterial colonizers. The epiphytic bacterial patterns and their temporal and spatial variability on host algae are poorly understood. To investigate the interaction between marine macroalgae and epiphytic bacteria, this study tested if the composition of epibacterial communities on different macroalgae was specific and persisted under varying biotic and abiotic environmental conditions over a 2-year observation time frame. Epibacterial communities on the co-occurring macroalgae Fucus vesiculosus, Gracilaria vermiculophylla and Ulva intestinalis were repeatedly sampled in summer and winter of 2007 and 2008. The epibacterial community composition was analysed by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene libraries. Epibacterial community profiles did not only differ significantly at each sampling interval among algal species, but also showed consistent seasonal differences on each algal species at a bacterial phylum level. These compositional patterns re-occurred at the same season of two consecutive years. Within replicates of the same algal species, the composition of bacterial phyla was subject to shifts at the bacterial species level, both within the same season but at different years and between different seasons. However, 7-16% of sequences were identified as species specific to the host alga. These findings demonstrate that marine macroalgae harbour species-specific and temporally adapted epiphytic bacterial biofilms on their surfaces. Since several algal host-specific bacteria were highly similar to other bacteria known to either avoid subsequent colonization by eukaryotic larvae or to exhibit potent antibacterial activities, algal host-specific bacterial associations are expected to play an important role for marine macroalgae.

Bacterial diversity in relation to secondary production and succession on surfaces of the kelp Laminaria hyperborea

“…It classifies as a member of the genus Granulosicoccus (Lee et al, 2007). Related sequences have been detected on the red seaweed Delisea pulchra, the green seaweed U. australis (Longford et al, 2007), the brown seaweed Fucus vesiculosus (Lachnit et al, 2010) and on the kelp (brown seaweed) Saccharina latissima (Staufenberger et al, 2008), suggesting that organisms within this genus share a preference for seaweeds. The alphaproteobacterial OTU 90 is less abundant (maximum 7.65%), yet frequently detected on L. hyperborea (Table 1, Figure 4a).…”

Permanent residents or temporary lodgers: characterizing intracellular bacterial communities in the siphonous green algaBryopsis

“…These bacteria have been especially well studied from terrestrial habitats [45,46], but have also been reported from marine habitats. Rhizobiales are common epiphytes of Ulva seaweeds [47][48][49][50] and have also been isolated from the surface of kelps where they display antimicrobial activity [13]. Additionally, a Rhodopseudomonas species with the potential to fix nitrogen was isolated from the rhizoidal cytoplasm of the siphonous green seaweed Caulerpa taxifolia [19].…”

Crustose coralline algal species host distinct bacterial assemblages on their surfaces

“…In some cases, algal species host specific bacterial assemblages across large geographic distances (Lachnit et al, 2009). To date, most studies on algal associated bacterial communities have focused on temperate, fleshy algal species (Lachnit et al, 2011) with the exception of a few studies of tropical fleshy algae (Barott et al, 2011;Sneed and Pohnert, 2011). Although CCA are known to be important settlement substrata for a number of invertebrate species and bacteria are known to produce chemical cues that induce invertebrate larval settlement, little is known about the bacterial communities associated with CCA.…”

“…Several studies have demonstrated that different species of macroalgae harbor unique bacterial communities (Longford et al, 2007;Lachnit et al, 2009Lachnit et al, , 2011Sneed and Pohnert, 2011). Within a given geographical area, bacterial communities are often more similar on individuals from the same algal species than they are to individuals from other algal species (Sneed and Pohnert, 2011).…”