Special Session 9: Microbial ecological processes and marine carbon cycle

The microbial degradation of dissolved organic matter release from Synechococcus by viral-lysis in coastal seawater
Tuesday 10th @ 0945-1010
Room 1
Zhao Zhao, Xiamen University
Michael Gonsior, University of Maryland Center for Environmental Science
Yuanchao Zhan, University of Maryland Center for Environmental Science
Rui Zhang, Xiamen University
Nianzhi Jiao, Xiamen University
Feng Chen* , University of Maryland Center for Environmental Science
Presenter Email:
Picocyanobacteria convert more than 50% of CO2 into organic carbon in the ocean. Meanwhile, viruses which infect picocyanobacteria like Synechococcus and Prochlorococcus are abundant and play pivotal role on the mortality of picocyanobacteria. Viral lysis of picocyanobacteria releases nutrient and organic compounds from picocyanobacteria. The released dissolved organic matter (DOM) from picocyanobacteria contributes to the ocean’s biogeochemical cycle. However, the fate and transport of virus-released DOM from picocyanobacteria have not been explored. We hypothesize that DOM released from viral lysis of cyanobacteria will change amount and chemical composition of marine DOM and the composition of bacterial community. In this study, we added viral-induced dissolved organic matter (VDOM) from a Synechococcus culture to a coastal microbial community to explore the fate of VDOM by monitoring the changes of abundance and composition of microbial communities and DOM over a 90-day period. Ultrahigh resolution mass spectrometry revealed that VDOM contained high intensity of CHNO chemical signatures, which were not observed in the coastal water DOM. Bacteria responded quickly to the spike of VDOM in 1-3 days, corresponding to a rapid decrease of the labile component of the VDOM at the same period. The addition of VDOM resulted in a dramatic succession of bacterial communities. The CHNO chemical molecules were mostly degraded within the 3 months of incubation. Our study suggested that the natural bacterial community was able to consume a large portion of VDOM rapidly. However, a significant portion of VDOM remained relatively stable over 3 months, suggesting that VDOM resulted from viral lysis of picocyanobacteria could be an important source of refractory DOM in the ocean.