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GENOME ENABLED ECOLOGY OF PSEUDO-NITZSCHIA INFECTING VIRUSES AND THEIR IMPACT ON PSEUDO-NITZSCHIA COMMUNITIES
Impact/Purpose:
To understand how viruses influence Pseudo-nitzschia community dynamics, a model host-virus system will be established with an isolated and characterized Pseudo-nitzschia-infecting virus. Using genomeenabled methods, the biogeography of Pseudo-nitzschia infecting viruses and their impact on Pseudo-nitzschia assemblages in the Pacific Northwest will be assessed.
Description:
With short infection cycles and large burst sizes (viruses per cell), the infection dynamics of diatom viruses appear to be optimized for rapidly growing diatom populations. On the timescale of bloom events, total Pseudo-nitzschia virus abundance should increase rapidly over the course of the bloom, while Pseudo-nitzschia abundance conversely should decline once a critical concentration of viruses is reached in the water column. If viruses are the cause of decline of a toxic bloom, by the nature of lysis, which releases cell contents into the water column, cellular domoic acid would be converted to dissolved DA and not be transferred up the food web. Additionally, this decline of Pseudo-nitzschia should lead to a shift in the overall phytoplankton community to either other diatom genera or other phytoplankton groups. Over the course of the season, Pseudo-nitzschia virus abundance should be correlated with diatom abundance and therefore be highest in the spring and summer. However, changes in the species composition of Pseudo-nitzschia communities, which generally shift from low toxin producers in the spring to high toxin producers in the fall, should be reflected in changes in viral diversity as well. Finally, both viral selection and environmental conditions lead to the various distinct Pseudo-nitzschia communities found in the Pacific Northwest.
Potential to Further Environmental/Human
Health Protection
Understanding Pseudo-nitzschia viruses has several implications for the
field dynamics of the diatoms it infects, such as limiting the duration and
mediating the impact of toxic Pseudo-nitzschia bloom events. Ultimately,
understanding how Pseudo-nitzschia communities are changing in space
and time is critical to the development of models that seek to forecast
potentially toxic events and can aid in the protection of commercial interests
and public health.