Planctomycetes in Lakes: Poor or Strong Competitors for Phosphorus?

Abstract

bExperiments were conducted with water samples from two perialpine lakes with differing eutrophication status in order to examine the effects of inorganic-nutrient amendments (nitrogen as NO 3 ؊ or NH 4 ؉ and phosphorus as PO 4 3؊ ) on the dynamics, structure, and composition of Planctomycetes and to test the hypothesis that the community structure of Planctomycetes members and that of the other bacteria (without Planctomycetes, here referred to as bacteria-wP, the most represented groups within the community) would be similarly impacted by nutrient additions. Initial samples were characterized by high total nitrogen-tototal phosphorus ratios (range, 39 to 55), suggesting P rather than N was the limiting nutrient for microbial communities. Consistent with this, P additions stimulated phytoplankton growth and affected the community structure of bacteria-wP but, surprisingly, not that of Planctomycetes. N additions did not significantly affect the community structures of bacteria-wP and Planctomycetes or the Planctomycetes phylotype composition. The estimated generation time of Planctomycetes was 123 h. These findings could suggest that the generally well-accepted statement that bacteria (as a whole) are superior to phytoplankton in the ability to obtain phosphorus under P limitation might actually not hold for Planctomycetes. Planctomycetes might be poor competitors for P that do not respond quickly to the nutrient supply, which may help explain why their abundance is low in aquatic systems. The alternative view that Planctomycetes could be strong competitors for P (storing it) is also discussed. Our findings highlight the need for further studies examining Planctomycetes-phosphorus relationships in aquatic ecosystems.

Insights into the cyanosphere: capturing the respective metabolisms of cyanobacteria and chemotrophic bacteria in natural conditions?

“…Nevertheless, some discrepancies were observed. For example, Planctomycetes that are commonly present in aquatic ecosystems at low abundances (Pollet et al ., 2014; Singer et al ., 2017; Faria et al ., 2018), were detected at the DNA‐level but not at the mRNA‐level. This could be explained by a low cellular activity for these bacteria in the environmental conditions sampled or by a low number of available Planctomycetes genomes in the reference databases leading to an ‘under‐assignation’ of mRNA from these bacteria.…”

The response of the soil bacterial community and function to forest succession caused by forest disease

“…thunbergii forms ectomycorrhizal (ECM) association (Phillips et al., 2013). Planctomycetes were proposed as slow‐growing bacteria that are at a disadvantage when competing with plants for nutrients, especially phosphorus (Fuerst, 1995; Pollet et al., 2014). The fast growth of L. formosana in the latter stage of succession might demand more nutrients than P. thunbergii , which could partially explain the decrease of Planctomycetes in abundance due to nutrient competition.…”

Planctomycetes as a Vital Constituent of the Microbial Communities Inhabiting Different Layers of the Meromictic Lake Sælenvannet (Norway)

“…These data, together with spatiotemporal abundance patterns (using CARD-FISH (catalyze reporter deposition fluorescence in situ hybridization)), were used to elucidate the evolutionary history of lacustrine Planctomycetes and their genome evolution patterns linked to their lifestyle strategies [ 5 ]. According to [ 6 ], Planctomycete abundance ranges from 0 to 11% of the aquatic planktonic prokaryotic community. Due to the relevance of Planctomycetes in nitrogen and carbon biogeochemical cycles [ 7 , 8 , 9 , 10 , 11 ], their potential role in aquatic ecosystem functioning is being recognized.…”