Microbial communities have a seasonal shake-up

KAUST researcher measure abundance of phytoplankton across the Red Sea to find variations between North and South and with changes of season.
© 2018 KAUST

Seasonal changes in turbulence and nutrient availability are shown to shape microbial communities in the Red Sea. “A lot of the marine ecosystem is ultimately based on how microbes live and what they’re doing,” explains research scientist John Pearman, who undertook the study. “Knowing how microbes respond is important to understand how the ecosystem is going to function.”

Using a CTD rosette sampler that combined sampling bottles with sensors for water temperature and conductivity, researchers in the Saudi Aramco-KAUST Center for Marine Environmental Observations measured water conditions and collected samples for the analysis of planktonic microbial communities in various parts of the Red Sea in different seasons. Sequencing rRNA genes from these samples gave them snapshots tracking how communities changed over time.

Led by marine scientists Susana Carvalho and Burton Jones, the research team found overall that diversity was greatest in the Southern Red Sea and lowest in the central region. However, communities varied across all regions and seasonally in both the North and the South. 

The Southern Red Sea had the lowest diversity during the fall, when high nutrient availability provided enough energy for larger plankton to grow, while low levels of turbulence minimized interactions with predators. As a result, these groups were able to dominate communities, diluting their richness. 

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