Effect of Availability of Nitrogen Compounds on Community Structure of Aquatic Bacteria in Model Systems

Abstract

To test if the quality and concentration of dissolved nitrogen (N) species could be a selective force in shaping bacterioplankton community structure, competition for various N compounds among five heterotrophic marine bacteria (Pseudomonas strains B, B25, and AX; Bacillus strain A6; Erythrobacter strain F19) was examined. Two of the five strains (AX and B25) were capable of utilizing urea for growth. The five strains were inoculated into dilute (1/1,000 strength) ZoBell medium enriched with various N sources (free amino acids, casein, ammonium, nitrate, or urea). Regardless of the added N source, the communities were either dominated by strain B (at 50 microM N) or strain AX (at 250 microM N). Without any addition of N, strain F19 dominated. If F19 was not included in the community, strain B25 dominated. Despite these differences in community structure, consumption of the added N compounds was surprisingly similar and no advantages of urea for the urea-utilizing bacterium B25 were obvious. To examine if urea could be of selective advantage to the urea-degrading strains B25 and AX, communities with and without B25 were amended with urea N. As expected, strain B25 became dominant when present, but without this strain the non-urea-utilizing strain B outcompeted the urea-utilizing strain AX. Possibly, strain B benefited from N released during catabolism of urea by strain AX. Changes in community composition did not result in major changes in the nitrogen dynamics. The results indicate that dissolved N species can be a selective force in shaping microbial communities. Relative to nutrient generalists, nutrient specialists may either have competitive advantages or stimulate growth of other species by synergetic interactions. Results from the model communities suggest that there may be a large degree of unpredictability in the making of microbial communities, whereas major ecosystem functions such as N cycling appear relatively stable.

Genetic and metabolic diversity of Arctic bacterioplankton during the post-spring phytoplankton bloom in Disko Bay, western Greenland

“…5). In a recent study by Frette et al (2009) it was demonstrated that availability of different dissolved species of nitrogen affected the community structure in model ecosystems. Therefore, the driving force for changing the bacterial community structure in Disko Bay was probably shifts in availability and composition of phytoplankton-derived DOM.…”

Community composition and activity state of estuarine bacterioplankton assessed using differential staining and metagenomic analysis of 16S rDNA and rRNA

“…Studies in diverse aquatic environments have shown that bacterial abundance and community composition covary with numerous factors including organic matter sources and composition (Cherrier et al 1996, Eiler et al 2003, nutrient availability (Stepanauskas et al 1999, Frette et al 2009), water temperature (Shiah & Ducklow 1994, McManus et al 2004, predation (Jürgens & Güde 1994, Gasol et al 2002, and viral lysis (Thingstad & Lignell 1997). Determining the relative importance of these factors is challenging, particularly in estuaries, which experience large and frequent changes in environmental conditions.…”

Tenacibaculum sediminilitoris sp. nov., isolated from a tidal flat

“…html; Parte, 2014;Kim et al, 2016). Members of the genus Tenacibaculum have been isolated from a variety of marine environments and marine organisms (Suzuki et al, 2001;Frette et al, 2004;Yoon et al, 2005;Sheu et al, 2007;Heindl et al, 2008;Piñeiro-Vidal et al, 2008Wang et al, 2008;Lee et al, 2009;Oh et al, 2012;Li et al, 2013;Kim et al, 2013Kim et al, , 2016. The aim of the present work was to determine the exact taxonomic position of strain YKTF-3 T by using a polyphasic characterization.…”