Author: Abbrar  Labban,   (Red Sea Research Center, King Abdullah University of Science and Technology)

Designation: 

Description:
Interactions between autotrophic and heterotrophic bacteria are fundamental for marine biogeochemical cycling. The impact of global warming on the dynamics of these essential microbial players is not well understood.  The aims of this study were to identify the major groups of heterotrophic bacteria present in two Red Sea Synechococcus and Proclorococcus cultures and to assess their responses to experimental warming using the metabolic theory of ecology (MTE). Synechococcus RS9907 and Proclorococcus RSP50 co-cultures were acclimated at different temperatures, from 24 to 34°C and 22 to 30˚C respectively, encompassing the Red Sea natural range. Three dominant heterotrophs (pertaining to the genera Paracoccus, Marinobacter, and Muricauda) were detected by 16S rRNA gene sequencing in the RS9907 co-culture. The temperature response of Synechococcus, which grew at 0.94-1.38 d^-1, estimated as the activation energy, was similar (0.34 ± 0.02 eV) to the value hypothesized by the MTE for autotrophs (0.32 eV), while the heterotrophic groups values ranged from 0.16 to 1.15 eV and were negatively correlated with their corresponding specific growth rates (2.38-24.4 d^-1). Preliminary results of the RSP50 co-culture showed higher activation energy of Prochlorococcus (0.45 ± 0.02 eV). Our findings suggest that the responses of bacterioplankton in microbial consortia to potential ocean warming might not be explained by theoretical universal rules. Future transcriptomic analysis will allow a deeper understanding of the bacterioplankton metabolic interactions in response to temperature.

Category: Scientific Program Abstract > Special Sessions > SS38 Too hot to handle? Getting to grips with global change impacts in subtropical and tropical coastal waters