Marine microbes: it’s the small things that count!

Bloom of Gonyaulax polygramma in False Bay (Photograph courtesy of Dr Grant Pitcher)

Did you know that marine microorganisms constitute over 90% of the living biomass in the ocean, and that viruses kill approximately 20% of this biomass daily (Suttle¹, 2007)?

It is estimated that there are more than 10³⁰ viruses in the ocean and that if these viruses were stretched out, end to end, they would extend further than the closest 60 galaxies!

Very little is known about the role of marine microorganisms in biogeochemical cycling and marine ecology, especially in South Africa. A Marine Microbes Workshop was recently held at the University of Cape Town (UCT) with the aim of uniting scientists from all over the Western Cape to discuss the possibilities of working together to gain a better understanding of microbial organisms in the oceans around South Africa. The purpose of the meeting was to allow participants to share expertise and to have an interdisciplinary discussion about the importance of marine microbes, with a particular focus on marine microbes in False Bay.

As an oceanographer and a SAEON intern, I joined a group of enthusiastic scientists (professors, researchers and students from UCT, the University of the Western Cape and Stellenbosch University) to discuss this hot topic.

Interdisciplinary discussion

Dr Maya Pfaff, a post-doc at UCT, explained how marine microbes (bacteria, archaea, viruses, protists and fungi) are vital to the functioning of all ecosystems and yet are extremely under-studied. Dr Coleen Moloney presented on how South Africa has little integrated research looking at marine microbes; we are falling behind the rest of the world with regard to understanding the role that these important organisms play in our ecosystems.

Professor Ed Rybicki explained how microbiologists are able to use flow cytometry to identify viruses. He mentioned that marine virology is very new to UCT and has only been a focus area since September 2012.

Integrated research

There is currently a project driven by Dr Juliet Hermes from SAEON, to collaborate research efforts in False Bay in order to gain a better understanding of the physical, biogeochemical and ecosystem processes within the bay. Local surfers and fishers often observe blooms of brown/green/red water in Muizenberg corner, the causes of which are not always clear to marine scientists. Microbiologists believe that it is highly likely that the termination of these phytoplankton blooms is determined by marine viruses.

The workshop inspired students and researchers to ask questions about the importance of marine viruses in all marine ecosystems, and has hopefully encouraged participants to join in field work in False Bay in the near future - to collect and analyse water samples for marine microbes and begin to understand the role that viruses play in our local ecosystem.

¹ Suttle, C. A. (2007). Marine viruses - major players in the global ecosystem. Nature Reviews Microbiology, 5(10), 801-812.