Viral shunt

The viral shunt is a mechanism that prevents marine microbial particulate organic matter (POM) from migrating up trophic levels by recycling them into dissolved organic matter (DOM), which can be readily taken up by microorganisms. The DOM recycled by the viral shunt pathway is comparable to the amount generated by the other main sources of marine DOM. Viruses can easily infect microorganisms in the microbial loop due to their relative abundance compared to microbes. Prokaryotic and eukaryotic mortality contribute to carbon nutrient recycling through cell lysis. There is evidence as well of nitrogen (specifically ammonium) regeneration. This nutrient recycling helps stimulates microbial growth. As much as 25% of the primary production from phytoplankton in the global oceans may be recycled within the microbial loop through the viral shunt. Viral shunt was first described in 1999 by Steven W. Wilhelm and Curtis A. Suttle. Their original paper has since been cited over 1000 times. For his contributions to understanding of viral roles in marine ecosystems, Suttle has received numerous awards, including being named a Fellow of the Royal Society of Canada, receiving the A.G. Huntsman Award for Excellence in Marine Science, and the Timothy R. Parsons Medal for Excellence in Ocean Sciences from the Department of Fisheries and Oceans. Both Suttle and Wilhelm have been elected Fellows of the American Academy of Microbiology as well as the Association for the Sciences of Limnology and Oceanography (ASLO). The field of marine virology has rapidly expanded since the mid-1990s, coinciding with the first publication of viral shunt. During this time, further studies have established the existence of the viral shunt as a "fact" of the field. The recycling of nutrients in the viral shunt has indicated to scientists that viruses are a necessary component in new models of global change. Virologists in soil sciences have begun to investigate the application of viral shunt to explain nutrient recycling in terrestrial systems.