Direct effects of organic pollutants on the growth and gene expression of the Baltic Sea model bacteriumRheinheimerasp.BAL341

Abstract

Summary Organic pollutants (OPs) are critically toxic, bioaccumulative and globally widespread. Moreover, several OPs negatively influence aquatic wildlife. Although bacteria are major drivers of the ocean carbon cycle and the turnover of vital elements, there is limited knowledge of OP effects on heterotrophic bacterioplankton. We therefore investigated growth and gene expression responses of the Baltic Sea model bacterium Rheinheimera sp. BAL341 to environmentally relevant concentrations of distinct classes of OPs in 2‐h incubation experiments. During exponential growth, exposure to a mix of polycyclic aromatic hydrocarbons, alkanes and organophosphate esters (denoted MIX) resulted in a significant decrease (between 9% and 18%) in bacterial abundance and production compared with controls. In contrast, combined exposure to perfluorooctanesulfonic acids and perfluorooctanoic acids (denoted PFAS) had no significant effect on growth. Nevertheless, MIX and PFAS exposures both induced significant shifts in gene expression profiles compared with controls in exponential growth. This involved several functional metabolism categories (e.g. stress response and fatty acids metabolism), some of which were pollutant‐specific (e.g. phosphate acquisition and alkane‐1 monooxygenase genes). In stationary phase, only two genes in the MIX treatment were significantly differentially expressed. The substantial direct influence of OPs on metabolism during bacterial growth suggests that widespread OPs could severely alter biogeochemical processes governed by bacterioplankton.

Labile Dissolved Organic Matter Compound Characteristics Select for Divergence in Marine Bacterial Activity and Transcription

“…In Baltic Sea experiments, Rheinheimera sp. were highly responsive to nutrient additions (e.g., glucose, ammonium, phosphate, n-alkanes) or changes in environmental conditions (Pinhassi and Berman, 2003;Lindh et al, 2015a;Karlsson et al, 2019). A search for Rheinheimera sp.…”

Genomic and Seasonal Variations among Aquatic Phages Infecting the Baltic Sea GammaproteobacteriumRheinheimerasp. Strain BAL341

“…Members of the bacterial genus Rheinheimera exist in various environments, and they have been found in soils (31) and aquatic habitats, including both freshwater (32) and marine (33) environments. They have also been shown to proliferate in more extreme environments, for example, in iron backwash sludge (34), and are able to degrade hydrocarbons such as n -alkanes (35). Bacteria within this genus have been detected in the brackish Baltic Sea (36), and transplant experiments with shifting salinities have noted stabilizing or increasing abundances as adjustment effects (37).…”

Field of the Dissolved Oil Products Concentration in the Sevastopol Bay Waters (the Black Sea)

“…By means of this device, arrays of synchronous measurements (in situ) of TSM and DOM contents in a sounding mode with a resolution of 0.1 m in depth were accumulated and analyzed. Note that the DOM, which characterizes anthropogenic, including bacterial, pollution, is attributed to one of the best water quality indicators in coastal marine and oceanic waters [10][11][12].…”