Kelpful interactions: microbial community assembly on Saccharina latissima under heat stress

Kelp forests are highly productive ecosystems in temperate coastlines that are threatened by increasing extreme temperature events in the Anthropocene. These rising temperatures cause cellular damage to many cold-adapted kelp species that can result in widespread population mortality. Coated in dense, diverse microbial biofilms, kelp blades are hotspots of microbial interactions, yet the ecological dynamics governing the assembly and succession of these communities remain largely unknown. Here, we conducted mesocosm experiments with Atlantic sugar kelp (Saccharina latissima) to investigate how microbial communities assemble and take over as the kelp grows from the youngest (meristem) to the oldest tissue (distal) under heat stress. Applying novel continuous diversity measures to 16S rRNA gene sequencing at high temporal and spatial resolutions, we aimed to determine whether random environmental colonization or host selectivity drives the community composition of kelp biofilms. Subsequently, we analyzed how these microbial dynamics are altered in physiologically stressed kelp under rising temperatures. By elucidating microbial successional patterns on kelp, this work sheds light on how kelp may selectively filter their microbiomes and how heat stress may disrupt this potentially symbiotic relationship, impacting kelp health and resilience in a changing climate.

Presentation Preference: Poster

Primary Presenter: Marcus Lin, McGill University (marcuslin@g.ucla.edu)

Authors:

Marcus Lin, McGill University  (marcus.lin@mail.mcgill.ca)

Daniel Gossard, Woods Hole Oceanographic Institute  (daniel.gossard@whoi.edu)

Scott Lindell, Woods Hole Oceanographic Institute  (slindell@whoi.edu)

Rowan Barrett, McGill University  (rowan.barrett@mcgill.ca)

Nagissa Mahmoudi, McGill University  (nagissa.mahmoudi@mcgill.ca)