The effect of bacteria on the growth and competitive ability of marine benthic diatoms

The interactions between marine benthic diatoms and bacteria found within biofilms can have important consequences for diatom growth dynamics. This thesis attempts to address the ecological nature of these interactions by means of co-culture experiments using different diatom and bacterial strains. Our results revealed the complexity of diatom-bacterial interactions which ranged from being synergistic to antagonistic in nature. Single-species interactions between different diatom strains revealed that bacterial-diatom interactions tend to be species-specific and dependent on nutrient conditions. Consequently, the presence of bacteria was beneficial to some diatoms while not for others. When diatoms were placed together with the addition of a bacterial inoculum, this yielded important consequences for the diatom-diatom interactions that were taking place. These competition experiments, revealed entire community shifts with the introduction of bacteria due to the resulting changes in different diatom species' growth rates. Lastly, our experiments also revealed bacterial species sorting taking place in the presence of diatoms and that these communities changed over time. Whether diatom-specificity amongst these bacterial communities was taking place was not quite clear. Nonetheless, these simple experimental set-ups highlight the importance of bacteria on diatom growth dynamics. These interactions have important ecological implications for community structure and functioning within the diatom formed biofilms. Further studies should be conducted in order to couple these results with their impact on processes such as biogeochemical cycling.

Promotor(s) & Supervisor: Koen Sabbe, Willem Stock
Thesis Institute: University of Ghent

ISCED Categories

The highlighted icons, represent the fields of education (in compliance with ISCED Classification) engaged during this course/programme.

0511 - Biology", "0521 - Ecology