Program     Bridging microbial diversity and chemodiversity of dissolved organic matter to better constrain processes in biogeochemical cycles       1010 Responses of marine bacterial community to dissolved organic matter released from viral lysis of picocyanobacteria - is there a correspondence between bacterial populations and molecular signatures of DOM? Tuesday 8th @ 1010-1030, Concert Hall Zhao Zhao* , Xiamen University Michael Gonsior, University of Maryland Center for Environmental Science Yuanchao Zhao, University of Maryland Center for Environmental Science Rui Zhang, Xiamen University Nianzhi Jiao, Xiamen Univeristy Feng Chen, University of Maryland Center for Environmental Science Presenter Email: zhaozhao28@foxmail.com Picocyanobacteria make up half of ocean primary production, and they are subjected to frequent viral infection. Viral lysis of picocyanobacteria is a major driving force converting biologically fixed carbon into dissolved organic carbon. Viral-induced dissolved organic matter (vDOM) released from picocyanobacteria provides complex organic matter to bacterioplankton in the marine ecosystem. In order to understand how picocyanobacterial vDOM are transformed by bacteria and the impact of this process on bacterial community structure, viral lysate of picocyanobacteria was incubated with a coastal water for 90 days. The transformation of vDOM was analyzed by ultrahigh-resolution mass spectrum and the shift of bacterial populations was analyzed using high-throughput sequencing technology. Addition of picocyanobacterial vDOM introduced abundant nitrogen components into the coastal water, which were largely degraded during the 90 days incubation period. However, some DOM molecules were accumulated and the total assigned formulae number increased. In contrast to the control (no addition of vDOM), bacterial community enriched with vDOM changed dramatically with increased biodiversity indices. The network analysis shows that certain bacterial OTUs form specific relationship with particular vDOM components, suggesting a potential correspondence between bacterial populations and DOM molecules. We demonstrate that coastal bacterioplankton are able to quickly utilize and transform lysis products of picocyanobacteria, meanwhile, bacterial community varies with changing chemical property of DOM.

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