Poster Presentation Society for Freshwater Science 2025 Annual Meeting

Land cover composition as the main driver of bacterioplankton communities along a Colombian Amazon hydrological network (118787)

Natalie Díaz Ruiz 1 , Juan Luis Parra 1 , María Carolina García-Chaves 1 , Marcela Núñez 2 , Sonia Sua 2 , Gladys Inés Cardona 2 , Hugo Sarmento 3 , Juan Pablo Niño-García 1
  1. University of Antioquia, Medellín, ANTIOQUIA, Colombia
  2. Instituto Sinchi, Bogotá, Colombia
  3. Universidade Federal de São Carlos, São Carlos, Brazil

The study of bacterial communities in aquatic ecosystems as hydrological networks requires a metacommunity framework; where local bacterioplankton communities are interconnected through water movement across the landscape. The evidence suggests that a balance between selection and dispersal processes drives bacterioplankton community composition, mainly through environmental filtering due to water conditions and taxa immigration from soil. However, little attention has been given to examining the impacts of the surrounding terrestrial landscape on these aquatic communities. In this study, we assessed the relative importance of terrestrial landscape composition, local aquatic conditions, and dendritic distance for explaining variations in aquatic bacterial communities along a small Amazonian hydrological network. We sampled 40 sites located in streams and oxbow lakes along a gradient of land cover composition, where we measured the local conditions of the water and quantified the distance between sites according to the flow of water course. Sequencing of the 16S rRNA gene allowed us to characterize the dissimilarity in the composition of the bacterial communities in the network. Using a Generalized Dissimilarity Model, we found that land cover composition had more explanatory power than local aquatic conditions and dendritic distance in explaining bacterial community dissimilarity, mainly in streams. Additionally, we observed significant differences in bacterioplankton composition between oxbow lakes and streams, which substantially differed according to local aquatic conditions. These findings underscore the critical role of both local aquatic conditions and land cover heterogeneity in determining bacterial community composition. Then, our results add landscape heterogeneity to previous evidence of selection factors in shaping bacterioplankton community structure in aquatic networks and establish clear links between freshwater and surrounding terrestrial environments. This could inspire innovative approaches to ecosystem conservation and biomonitoring strategies that include bacterioplankton.

  1. Niño-García JP, Ruiz-González C, Del Giorgio PA. Interactions between hydrology and water chemistry shape bacterioplankton biogeography across boreal freshwater networks. ISME J. 2016;10(7):1755–66. This is related to the importance of water residence time in evironmental filtering by water chemistry for structuring bacterioplankton communties.
  2. Brown BL, Swan CM. Dendritic network structure constrains metacommunity properties in riverine ecosystems. J Anim Ecol. 2010;79(3):571–80 This is related to the importance of aquatic network structure and its connectivity for the structuring of metacommunities.
  3. Shu W, Wang P, Xu Q, Zeng T, Ding M, Zhang H, et al. Coupled effects of landscape structures and water chemistry on bacterioplankton communities at multi-spatial scales. Sci Total Environ [Internet]. 2022;811:151350. Available from: https://doi.org/10.1016/j.scitotenv.2021.151350 This reference discusses about the relative importance of land use and water chemistry on variation of bacterioplankton communities composition, another effort to understand the role of the terrestrial landscape in structuring aquatic bacterial communitites.