Talk title: Latitude, depth or season? What explains the distribution of Red Sea pelagic heterotrophic prokaryotes?

Presenter: Tamara Huete-Stauffer

Date: November 20, 2018
Time: 3 - 4 pm
Location: Auditorium level 0, between buildings 2 and 3

Abstract:  Prokaryotes are responsible for a major fraction of the cycling of nutrients and carbon in the ocean, especially in oligotrophic waters like the Red Sea. Prokaryotes are expected to respond to environmental parameters that vary markedly in the Red Sea with changes in, for example, depth, latitude or season. 

We were interested in learning which of these gradients had a greater effect on the Red Sea prokaryotes by analyzing flow cytometric samples compiled from 8 different cruises spanning from 2014 to 2018. During this seminar, I will show the patterns we observed of abundance, biomass, and size of heterotrophic prokaryotes, and how they respond to environmental gradients.

Talk title: Weekly variation of viruses and heterotrophic nanoflagellates and their potential impact on bacterioplankton in a Red Sea shallow ecosystem

Presenter: Eman Sabbagh

Date: November 21, 2018
Time: 3 - 4 pm
Location: Auditorium level 0, between buildings 2 and 3

Abstract:  In this study we aimed to describe the high frequency variability of planktonic bacteria in KAUST Harbor waters and the relative importance of top-down (mortality by viruses and heterotrophic nanoflagellates) and bottom-up (nutrient availability) controls. 

Top-down factors seemed more important than bottom-up ones in regulating the standing stocks of heterotrophic bacteria, with viruses playing a major role especially in spring and summer.