Distribution Patterns of Microbial Community Structure Along a 7000-Mile Latitudinal Transect from the Mediterranean Sea Across the Atlantic Ocean to the Brazilian Coastal Sea

Abstract

A central goal in marine microecology is to understand the ecological factors shaping spatiotemporal microbial patterns and the underlying processes. We hypothesized that abiotic and/or biotic interactions are probably more important for explaining the distribution patterns of marine bacterioplankton than environmental filtering. In this study, surface seawater samples were collected about 7000 miles from the Mediterranean Sea, transecting the North Atlantic Ocean, to the Brazilian marginal sea. In bacterial biosphere, SAR11, SAR86, Rhodobacteraceae, and Rhodospiriaceae were predominant in the Mediterranean Sea; Prochlorococcus was more frequent in Atlantic Ocean; whereas in the Brazilian coastal sea, the main bacterial members were Synechococcus and SAR11. With respect to archaea, Euryarchaeota were predominant in the Atlantic Ocean and Thaumarchaeota in the Mediterranean Sea. With respect to the eukaryotes, Syndiniales, Spumellaria, Cryomonadida, and Chlorodendrales were predominant in the open ocean, while diatoms and microzooplankton were dominant in the coastal sea. Distinct clusters of prokaryotes and eukaryotes displayed clear spatial heterogeneity. Among the environmental parameters measured, temperature and salinity were key factors controlling bacterial and archaeal community structure, respectively, whereas N/P/Si contributed to eukaryotic variation. The relative contribution of environmental parameters to the microbial distribution pattern was 45.2%. Interaction analysis showed that Gammaproteobacteria, Alphaproteobacteria, and Flavobacteriia were the keystone taxa within the positive-correlation network, while Thermoplasmata was the main contributor in the negative-correlation network. Our study demonstrated that microbial communities are co-governed by environmental filtering and biotic interactions, which are the main deterministic driving factors modulating the spatiotemporal patterns of marine plankton synergistically at the regional or global levels.

Diatoms shape the biogeography of heterotrophic prokaryotes in early spring in the Southern Ocean

“…Dispersal and drift are additional factors that were identified in biogeographic studies (Lindström and Langenheder, 2012;Wilkins et al, 2013). In contrast, the potential influence of the community composition of microorganisms that can interact with heterotrophic microbes has only recently been taken into consideration in this context (Lima-Mendez et al, 2015;Milici et al, 2016;Zhou et al, 2018). The present study reveals that the spatial pattern in the community structure of heterotrophic microbes in surface waters is tightly associated with changes in the diatom assemblages, rather than to geographic distance and environmental conditions.…”

“…SA11 and Thalassiosira pseudonana with Croceibacter atlanticus van Tol et al, 2017). These findings in combination with the observed co-occurrence of microbial taxa (Gilbert et al, 2012;Lima-Mendez et al, 2015;Milici et al, 2016;Needham and Fuhrman, 2016;Zhou et al, 2018) raise the question of whether interactions have the potential to drive biogeographic patterns of microbial communities in the aquatic environment.…”

“…Using the exudate of a common diatom species as a growth substrate in an experimental approach and in situ observations allowed to establish a link between substrate preferences of several prokaryotic taxa and their presence during spring phytoplankton blooms in the Southern Ocean (Landa et al, 2016). The reported co-occurrence patterns between eukaryotic and prokaryotic taxa extend the potential importance of biotic interactions to larger temporal and spatial scales (Gilbert et al, 2012;Lima-Mendez et al, 2015;Milici et al, 2016;Needham and Fuhrman, 2016;Zhou et al, 2018). These networks could in part be driven by the exchange of a suite of metabolites, discovered in experimental studies using model organisms.…”

“…The production of siderophores by Marinobacter sp. These findings in combination with the observed co-occurrence of microbial taxa (Gilbert et al, 2012;Lima-Mendez et al, 2015;Milici et al, 2016;Needham and Fuhrman, 2016;Zhou et al, 2018) raise the question of whether interactions have the potential to drive biogeographic patterns of microbial communities in the aquatic environment. Diatom cell division was recently shown to be regulated by the excretion of hormones released by prokaryotes based on the co-cultured Pseudo-nitzschia multiseries with Sulfitobacter sp.…”

Insights into protist diversity and biogeography in intertidal sediments sampled across a range of spatial scales

“…It is now widely accepted that both selective and neutral processes are involved in the assembly of microbial communities, but their relative importance remains intensely debated (Zhou et al ; Stegen et al ; Mo et al ). For example, Zhou et al () found that microeukaryote communities were shaped by environmental selection and biological interactions, which are the main deterministic driving factors governing the distribution patterns of marine plankton at global scales. In contrast, Bahram et al () provide empirical evidence that neutral processes play the dominant role in the distribution of soil microeukaryotes at local levels.…”