Viruses in Marine Planktonic Systems (original) (raw)

Impact of viruses on bacterial communities in marine systems

2009

Memoria de tesis doctoral presentada por Julia Anna Boras para optar al grado de Doctora por la Universitat de Barcelona (UB), realizada bajo la direccion de la Dra. Ma Dolors Vaque Vidal y la Dra. Maria Montserrat Sala Farre del Institut de Ciencies del Mar (ICM-CSIC) y la Dra. Montserrat Vidal.-- 222 pages

Bridging the Gap between Knowing and Modeling Viruses in Marine Systems—An Upcoming Frontier

Frontiers in Marine Science, 2017

Viruses are the most abundant biological entities in the world's oceans. Their potential control on the dynamics and diversity of bacterioplankton and some phytoplankton groups, and consequent effect on the flow of energy and matter in food webs, may be argued as beyond dispute. Paradoxically, their importance seems to be persistently underestimated by marine modelers, frequently by exclusion, despite the uninterrupted volume of knowledge advanced during the past decades. Bridging the gap between knowing and modeling the role of viruses is, undoubtedly, one of the upcoming frontiers to be crossed in modeling the plankton. This paper has a twofold objective: (1) review the knowledge on the roles of viruses in marine systems that has been put forward over the past decades, and (2) see how viruses have been incorporated into marine ecosystem models, along with the factors that are limiting their inclusion.

Major viral impact on the functioning of benthic deep-sea ecosystems

Nature, 2008

Viruses are the most abundant biological organisms of the world's oceans. Viral infections are a substantial source of mortality in a range of organisms-including autotrophic and heterotrophic plankton-but their impact on the deep ocean and benthic biosphere is completely unknown. Here we report that viral production in deep-sea benthic ecosystems worldwide is extremely high, and that viral infections are responsible for the abatement of 80% of prokaryotic heterotrophic production. Virus-induced prokaryotic mortality increases with increasing water depth, and beneath a depth of 1,000 m nearly all of the prokaryotic heterotrophic production is transformed into organic detritus. The viral shunt, releasing on a global scale ,0.37-0.63 gigatonnes of carbon per year, is an essential source of labile organic detritus in the deep-sea ecosystems. This process sustains a high prokaryotic biomass and provides an important contribution to prokaryotic metabolism, allowing the system to cope with the severe organic resource limitation of deep-sea ecosystems. Our results indicate that viruses have an important role in global biogeochemical cycles, in deep-sea metabolism and the overall functioning of the largest ecosystem of our biosphere.

Viral infection of prokaryotic plankton during early formation of the North West Atlantic Deep Water

Aquatic Microbial Ecology, 2020

Viral abundance was assessed in different water masses of the NW Atlantic, and the development of viral abundance, lytic viral infection and lysogeny was followed for the first ca. 5000 km (corresponding to ca. 50 yr in the oceanic conveyor belt) of the western branch of the North Atlantic Deep Water (NADW). Viral abundance was significantly higher in the 100 m layer than in the NADW (2400-2700 m depth) and the Denmark Strait Overflow Water (2400-3600 m depth). The virus-to-prokaryote ratio (VPR) increased with depth, ranging from 32-43 for different water masses of the bathypelagic ocean, thus corroborating the enigma of high viral abundance in the dark ocean. The O2-minimum layer (250-600 m) also showed high viral abundance and VPRs. Viral abundance, a viral subgroup and VPRs decreased in a non-linear form with distance from the NADW origin. Viral production (range: 0.2-2.4 × 107 viruses l-1) and the fraction of lytically infected cells (range: 1-22%) decreased with increasing dis...

A systematic analysis of marine lysogens and proviruses

Nature Communications

Viruses are ubiquitous in the oceans, exhibiting high abundance and diversity. Here, we systematically analyze existing genomic sequences of marine prokaryotes to compile a Marine Prokaryotic Genome Dataset (MPGD, consisting of over 12,000 bacterial and archaeal genomes) and a Marine Temperate Viral Genome Dataset (MTVGD). At least 40% of the MPGD genomes contain one or more proviral sequences, indicating that they are lysogens. The MTVGD includes over 12,900 viral contigs or putative proviruses, clustered into 10,897 viral genera. We show that lysogens and proviruses are abundant in marine ecosystems, particularly in the deep sea, and marine lysogens differ from non-lysogens in multiple genomic features and growth properties. We reveal several virus-host interaction networks of potential ecological relevance, and identify proviruses that appear to be able to infect (or to be transferred between) different bacterial classes and phyla. Auxiliary metabolic genes in the MTVGD are enric...

Lysogenic and lytic viral production in marine microbial communities

Aquatic Microbial Ecology, 1997

It is now well established that viruses are an abundant component of marine ecosystems and they are being increasingly recognised and accepted as important contnbutors to element cycling within the microbial loop. However, some of the key questions regarding the ecological significance of viruses in the marine environment still remain largely unanswered. Thus, particular interest is currently focused on the extent to which lytic production or lysoyeny predominates and the nature of factors in the marine environment, particularly nutrient availability and mult~plicity of .infection (MOI), which might influence the lysisflysogeny 'decision' The present evidence is still insufficient to unambiguously assess the relative ecological significance of lysogeny versus lysis and progress in this area will rely on the development and application of new techniques. This review attempts to collect recent information relating to this central question, focusing particularly on those viruses which infect the bacterioplankton and nano-and picophytoplankton.