ussed for nearly two decades now, yet the quantitative impact viruses have on regional and global scale processes remains generally unresolved apart from estimates from a few marine virus production surveys [e.g. 32,38,40,41,77-81]. This uncertainty with respect to quantifying viral effects manifests itself in two critical ways. First, there are a number of global earth systems and climate models that integrate geophysical processes with the biology of microbes to metazoans to predict the dynamics of carbon nutrients and biodiversity [82-84]. However, the smallest biotic agents on the planet – viruses – are rarely, if ever, included in such models. Second, the most recent Intergovernmental Panel on Climate Change released its last report in 2007 noting: “The overall reaction of marine biological carbon cycling (including processes such as nutrient cycling as well as ecosystem changes including the role of bacteria and viruses) to a warm and high-CO2 world is not yet well understood. Several small feedback mechanisms may add up to a significant one” . The emphasis is ours. The assessment of quantitative effects of viruses on populations, communities and ecosystems in a form that can be integrated into large-scale models and climate change scenarios should be a major research goal.
There are many challenges to reach this goal. First, data on the quantitative effects of viruses on ecosystem processes are highly variable, and may reflect differences in collection and estimation methods in addition to natural biological variation. There is a need for increased standardization of methods (e.g. ) as well as the integration of existing data to relate viral interaction and effect data to environmental and geographic drivers. Second, new methods are being developed to characterize the genomes of viruses of microbes and the microbes they infect (e.g. ). Yet, how much do these details matter? That is, are there particular host-viral interactions, and even particular lineages or ecotypes, that are key to the flux of particular types of organic and inorganic pools? Multi-scale mathematical methods can help infer viral effects at large scale based on cellular level interactions. Finally, there is a growing emphasis on the quantification of genomic and transcriptomic diversity within ocean microbes. However, predicting ecosystem-level effects of viruses of microbes requires quantitative estimates of rates and interactions coinciding with genomic and transcriptomic surveys. We hope that future work on viruses of microbes in the oceans includes efforts to combine rates, -omics data and mathematical models in the service of answering a fundamental question: what effects do viruses have on the global earth system?
The authors declare that they have no competing interests.
Joshua S. Weitz holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund and acknowledges the support of an award from the James S. McDonnell Foundation. Steven W. Wilhelm acknowledges support from the National Science Foundation, Division of Biological and Chemical Oceanography and the Division of Environmental Biology. This work was conducted as a part of the Ocean Viral Dynamics Working Group at the National Institute for Mathematical and Biological Synthesis, sponsored by the National Science Foundation, the U.S. Department of Homeland Security, and the U.S. Department of Agriculture through NSF Award #EF-0832858, with additional support from The University of Tennessee, Knoxville
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