Presentation Abstract
Canopy-forming kelps create vast underwater forests that are among the most productive marine ecosystems. In addition to providing vital habitat for macroscopic organisms, kelps also host an abundant microbial community in their surface mucus layer. In the Salish Sea, two canopy-forming kelps with contrasting life histories co-occur; Macrocystis pyrifera, a perennial species, and Nereocystis luetkeana, an annual species. Kelp-associated microbial communities were sampled along a spatial gradient, including sites from the outer Olympic Coast, Strait of Juan de Fuca, and Puget Sound. We characterized the microbial communities associated with each kelp species and the surrounding seawater using next-generation Illumina sequencing of 16S rRNA genes. Our preliminary results show that canopy-forming kelps host complex microbial symbiont communities that are host-specific and distinct from free-living bacteria in the surrounding seawater. Based on fluorescence microscopy data, up to 25 million bacteria live on just one square centimeter of N. luetkeana tissue. In addition to examining spatial variation in the kelp microbiome, we examined the impact of N. luetkeana and M. pyrifera kelp forests on the surrounding seawater chemistry. We used an enriched carbon stable isotope tracer experiment (13C-bicarbonate) to demonstrate simultaneous carbon fixation and dissolved organic carbon (DOC) production by N. luetkeana from Tatoosh Island, WA. During the daytime, carbon fixed by N. luetkeana is leaked into the surrounding seawater at a rate of 10 μmol DOC per hour per gram of dry mass. This carbon presents an abundant food resource for heterotrophic microbes in the surrounding seawater. Given the immense surface area of kelp forests, the kelp microbiome has potentially far-reaching impacts on kelp forest productivity and coastal nutrient cycling.
Session Title
Kelp Distribution and Recovery Strategies in the Salish Sea: Part II
Keywords
Nereocystis, Macrocystis, Microbes, Carbon cycling
Conference Track
SSE1: Habitat Restoration and Protection
Conference Name
Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)
Document Type
Event
SSEC Identifier
SSE1-235
Start Date
6-4-2018 10:30 AM
End Date
6-4-2018 10:45 AM
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Kelp bed ecology--Washington (State)--Puget Sound Watershed; Algal communities--Washington (State)--Puget Sound Watershed; Marine ecosystem management--Washington (State)--Puget Sound Watershed; Marine microbial ecology--Washington (State)--Puget Sound Watershed
Geographic Coverage
Salish Sea (B.C. and Wash.); Puget Sound Watershed (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Included in
Fresh Water Studies Commons, Marine Biology Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons
The microbiome of the canopy-forming kelps, Nereocystis and Macrocystis, from the outer Olympic Coast to the Puget Sound
Canopy-forming kelps create vast underwater forests that are among the most productive marine ecosystems. In addition to providing vital habitat for macroscopic organisms, kelps also host an abundant microbial community in their surface mucus layer. In the Salish Sea, two canopy-forming kelps with contrasting life histories co-occur; Macrocystis pyrifera, a perennial species, and Nereocystis luetkeana, an annual species. Kelp-associated microbial communities were sampled along a spatial gradient, including sites from the outer Olympic Coast, Strait of Juan de Fuca, and Puget Sound. We characterized the microbial communities associated with each kelp species and the surrounding seawater using next-generation Illumina sequencing of 16S rRNA genes. Our preliminary results show that canopy-forming kelps host complex microbial symbiont communities that are host-specific and distinct from free-living bacteria in the surrounding seawater. Based on fluorescence microscopy data, up to 25 million bacteria live on just one square centimeter of N. luetkeana tissue. In addition to examining spatial variation in the kelp microbiome, we examined the impact of N. luetkeana and M. pyrifera kelp forests on the surrounding seawater chemistry. We used an enriched carbon stable isotope tracer experiment (13C-bicarbonate) to demonstrate simultaneous carbon fixation and dissolved organic carbon (DOC) production by N. luetkeana from Tatoosh Island, WA. During the daytime, carbon fixed by N. luetkeana is leaked into the surrounding seawater at a rate of 10 μmol DOC per hour per gram of dry mass. This carbon presents an abundant food resource for heterotrophic microbes in the surrounding seawater. Given the immense surface area of kelp forests, the kelp microbiome has potentially far-reaching impacts on kelp forest productivity and coastal nutrient cycling.
