Author:
Huber Paula,De Angelis Daniele,Sarmento Hugo,Metz Sebastian,Giner Caterina R.,Vargas Colomban De,Maiorano Luigi,Massana Ramon,Logares Ramiro
Abstract
Abstract
Background
The backbone of the eukaryotic tree of life contains taxa only found in molecular surveys, of which we still have a limited understanding. Such is the case of Picozoa, an enigmatic lineage of heterotrophic picoeukaryotes within the supergroup Archaeplastida, which has emerged as a significant component of marine microbial planktonic communities. To enhance our understanding of the diversity, distribution, and ecology of Picozoa, we conduct a comprehensive assessment at different levels, from assemblages to taxa, employing phylogenetic analysis, species distribution modeling, and ecological niche characterization.
Results
Picozoa was among the ten most abundant eukaryotic groups, found almost exclusively in marine environments. The phylum was represented by 179 Picozoa’s OTU (pOTUs) placed in five phylogenetic clades. Picozoa community structure had a clear latitudinal pattern, with polar assemblages tending to cluster separately from non-polar ones. Based on the abundance and occupancy pattern, the pOTUs were classified into four categories: Low-abundant, Widespread, Polar, and Non-polar. We calculated the ecological niche of each of these categories. Notably, pOTUs sharing similar ecological niches were not closely related species, indicating a phylogenetic overdispersion in Picozoa communities. This could be attributed to competitive exclusion and the strong influence of the seasonal amplitude of variations in environmental factors, such as temperature, shaping physiological and ecological traits.
Conclusions
Overall, this work advances our understanding of uncharted protists’ evolutionary dynamics and ecological strategies. Our results highlight the importance of understanding the species-level ecology of marine heteroflagellates like Picozoa. The observed phylogenetic overdispersion challenges the concept of phylogenetic niche conservatism in protist communities, suggesting that closely related species do not necessarily share similar ecological niches.
Funder
Fundação de Amparo à Pesquisa do Estado de São Paulo
H2020 Excellent Science
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Severo Ochoa Centre of Excellence
Consejo Superior de Investigaciones Cientificas
Publisher
Springer Science and Business Media LLC
Reference101 articles.
1. Falkowski PG, Fenchel T, Delong EF. The microbial engines that drive earth’s biogeochemical cycles. Science. 1979;2008(320):1034–9.
2. Guidi L, Chaffron S, Bittner L, Eveillard D, Larhlimi A, Roux S, et al. Plankton networks driving carbon export in the oligotrophic ocean. Nature. 2016;532:465–70.
3. Sherr E, Sherr B. Understanding roles of microbes in marine pelagic food webs: a brief history. In: Microbial ecology of the oceans: second edition. 2008. p. 27–44.
4. de Vargas C, Audic S, Henry N, Decelle J, Mahé F, Logares R, et al. Eukaryotic plankton diversity in the sunlit ocean. Science. 1979;2015(348):1261605–1261605.
5. Massana R. Protistan diversity in environmental molecular surveys. In: Marine protists. Tokyo: pringer Japan; 2015. p. 3–21.