Browsing by Author "Gouraguine, Adam"

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    Multiscale Spatial Variability and Stability in the Structure and Diversity of Bacterial Communities Associated with the Kelp Eisenia cokeri in Peru
    (2023) King, Nathan G.; Uribe, Roberto; Moore, Pippa J.; Earp, Hannah S.; Gouraguine, Adam; Hinostroza, Diego; Perez-Matus, Alejandro; Smith, Kathryn; Smale, Dan A.
    Ecological communities are structured by a range of processes that operate over a range of spatial scales. While our understanding of such biodiversity patterns in macro-communities is well studied, our understanding at the microbial level is still lacking. Bacteria can be free living or associated with host eukaryotes, forming part of a wider "microbiome," which is fundamental for host performance and health. For habitat forming foundation-species, host-bacteria relationships likely play disproportionate roles in mediating processes for the wider ecosystem. Here, we describe host-bacteria communities across multiple spatial scales (i.e., from 10s of m to 100s of km) in the understudied kelp, Eisenia cokeri, in Peru. We found that E. cokeri supports a distinct bacterial community compared to the surrounding seawater, but the structure of these communities varied markedly at the regional (similar to 480 km), site (1-10 km), and individual (10s of m) scale. The marked regional-scale differences we observed may be driven by a range of processes, including temperature, upwelling intensity, or regional connectivity patterns. However, despite this variability, we observed consistency in the form of a persistent core community at the genus level. Here, the genera Arenicella, Blastopirellula, Granulosicoccus, and Litorimonas were found in >80% of samples and comprised similar to 53% of total sample abundance. These genera have been documented within bacterial communities associated with kelps and other seaweed species from around the world and may be important for host function and wider ecosystem health in general.
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    The intensity of kelp harvesting shapes the population structure of the foundation species Lessonia trabeculata along the Chilean coastline
    (2021) Gouraguine, Adam; Moore, Pippa; Burrows, Michael T.; Velasco, Eliana; Ariz, Luis; Figueroa-Fabrega, Luis; Munoz-Cordovez, Rodrigo; Fernandez-Cisternas, Italo; Smale, Dan; Perez-Matus, Alejandro
    Kelp are foundation species that support high levels of biodiversity and, either directly or indirectly provide a wide range of ecological goods and services to human society. In recent decades, due to the high demand for kelp-derived products such as alginate, commercial wild harvesting has increased, leading to declines of kelp biomass in some regions. Chile accounts for 40% of the global kelp harvest, with the subtidal kelp, Lessonia trabeculata being one of the main target species. Currently, however, there is a lack of information on how different degrees of harvesting intensity, governed by distinct management regimes and their enforcement influences L. trabeculata populations. Here we examined the effect different management regimes, characterised by distinct levels of exploitation of kelp and kelp-associated fauna, have on L. trabeculata density and morphology along similar to 1600 km of the Chilean coastline. The findings demonstrated that harvesting intensity likely influences both L. trabeculata density and morphology. Juvenile density of L. trabeculata was five times higher in the most harvesting-affected areas, while kelp morphology values, including holdfast diameter, number of stipes and total length, were always higher in the less-intensively harvested areas. Our study suggests that different degrees of protection can influence density and morphology of subtidal L. trabeculata populations, which in turn has important implications for the conservation of the kelp forest ecosystems and management of this important fishery.