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General Session 3: Biological oceanography & global change |
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Innovative conceptual models for quantitative analysis of viral shunt in nutrient cycling
GS3-31
Yu Li* , University of Massachusetts
Rui Zhang, Xiamen University
Presenter Email: liyukaoyan@sina.com
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| Viruses play an important role in aquatic ecosystems and their activities have been increasingly studied in carbon (C) and nutrient cycling, such as, viral shunt.The latter refers to viruses move C and nutrient fluxes from phytoplankton and bacteria to organic matter. However, most present models, mainly based on the simple ‘consumer’ view, the ‘Nutrient-Phytoplankton-Zooplankton’ (NPZ) model , do not always provide an accurate picture of C and nutrient cycling due to the complicated nature of microbial interactions. This study used the Framework for Aquatic Ecosystem Models (FABM) to develop three improved ecological models of different structural complexity for exploring the role of viral shunt in nutrient cycling. The ‘Nutrient-Phytoplankton-Zooplankton-Detritus+Bacteria’ (NPZD+B) model was developed for describing the microbial loop. The ‘Nutrient-Phytoplankton-Zooplankton-Detritus+Viruses’ (NPZD+V) model was comparatively developed for depicting the viral shunt. The ‘Nutrient-Phytoplankton-Zooplankton-Detritus+Viruses +Bacteria’ (NPZD+VB) model was further developed for investigating the impact of the viral shunt on the microbial loop. The results indicated that virus mediated mortality on phytoplankton via infection and lysis is as important as zooplankton mediated mortality via grazing on phytoplankton. The results indicated that the viral shunt could short circuit the microbial loop via viral infection and lysis of phytoplankton and bacteria, and thereby increased the transfer of nutrients to detritus. The study can help to guide decisions about adopting appropriate model conceptualisations, and provide an improved mechanistic understanding for viral-bacterial-phytoplankton-zooplankton interactions in aquatic ecosystems. |
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