Dilution-to-extinction culturing of SAR11 members and other marine bacteria from the Red Sea

  • Roslinda B. Mohamed

Student thesis: Master's Thesis


Life in oceans originated about 3.5 billion years ago where microbes were the only life form for two thirds of the planet’s existence. Apart from being abundant and diverse, marine microbes are involved in nearly all biogeochemical processes and are vital to sustain all life forms. With the overgrowing number of data arising from culture-independent studies, it became necessary to improve culturing techniques in order to obtain pure cultures of the environmentally significant bacteria to back up the findings and test hypotheses. Particularly in the ultra-oligotrophic Red Sea, the ubiquitous SAR11 bacteria has been reported to account for more than half of the surface bacterioplankton community. It is therefore highly likely that SAR11, and other microbial life that exists have developed special adaptations that enabled them to thrive successfully. Advances in conventional culturing have made it possible for abundant, unculturable marine bacteria to be grown in the lab. In this study, we analyzed the effectiveness of the media LNHM and AMS1 in isolating marine bacteria from the Red Sea, particularly members of the SAR11 clade. SAR11 strains obtained from this study AMS1, and belonged to subgroup 1a and phylotype 1a.3. We also obtained other interesting strains which should be followed up with in the future. In the long run, results from this study will enhance our knowledge of the pelagic ecosystem and allow the impacts of rising temperatures on marine life to be understood.
Date of AwardDec 2013
Original languageEnglish (US)
Awarding Institution
  • Biological, Environmental Sciences and Engineering
SupervisorUlrich Stingl (Supervisor)


  • Marine Microbiology
  • SAR11
  • Red Sea
  • Dilution-to-Extinction

Cite this