Abstract
Viruses are key biogeochemical engines in the regulation of the dynamics of phytoplankton. However, there has been little research on viral communities in relation to algal blooms. Using the virMine tool, we analyzed viral information from metagenomic data of field dinoflagellate (Gymnodinium catenatum) blooms at different stages. Species identification indicated that phages were the main species. Unifrac analysis showed clear temporal patterns in virioplankton dynamics. The viral community was dominated by Siphoviridae, Podoviridae, and Myoviridae throughout the whole bloom cycle. However, some changes were observed at different phases of the bloom; the relatively abundant Siphoviridae and Myoviridae dominated at pre-bloom and peak bloom stages, while at the post-bloom stage, the members of Phycodnaviridae and Microviridae were more abundant. Temperature and nutrients were the main contributors to the dynamic structure of the viral community. Some obvious correlations were found between dominant viral species and host biomass. Functional analysis indicated some functional genes had dramatic response in algal-associated viral assemblages, especially the CAZyme encoding genes. This work expands the existing knowledge of algal-associated viruses by characterizing viral composition and function across a complete algal bloom cycle. Our data provide supporting evidence that viruses participate in dinoflagellate bloom dynamics under natural conditions.
Highlights
Phytoplankton are important primary producers in marine ecosystems and play a critical role in element cycling, food web production, and broader ecosystem functions [1,2,3]
MaxBin 2.0 was used to perform scaffold binning by adopting the following conditions: (1) assembled scaffolds had lengths >1000 bp; (2) tetranucleotide frequencies and coverage level of scaffolds were calculated; (3) the parameters were substituted into the expectation maximization (EM) algorithm to calculate the probability that all scaffolds belong to each bin
The target species was G. catenatum, and cell concentrations ranged from (0.51 ± 0.042) × to (5.4 ± 0.61) × cells/mL, with the highest biomass appearing at the peak stage (p < 0.01)
Summary
Phytoplankton are important primary producers in marine ecosystems and play a critical role in element cycling, food web production, and broader ecosystem functions [1,2,3]. Biological agents, including plants [8], protozoa [9], bacteria [10], and viruses [11], are considered to be effective and biosecure ways of influencing HAB occurrence and dynamics, and the relationship between microbes and algae has received particular interest in recent years This partly is due to the roles of microbes in mediating matter cycling, micro-food web structures, and the production of essential elements that stimulate algal growth [12,13,14] as well as in absorbing essential elements [15], exhibiting algicidal activity [16,17], inhibiting sexual reproduction [18], and regulating algae–bacteria signaling (such as quorum sensing) [19]. The results may contribute to the current understanding of the viral regulatory role in algal bloom events
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
