Virus Size & Structure 1 Micron Chlamydia Pox virus Herpes virus Influenza Virus Bacterium (Staphyllococcusaureus) Picornavirus (polio) Relative size of viruses and bacteria
Microbial Loop CO2 DOC Higher Trophic Levels Bacteria Lysis Viruses Decay Figure Adapted from Sawstrom, Viral Dynamics in the Microbial Loop
Viruses in the Marine Environment The estimated 1030 viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies.
Characteristics of Aquatic Viruses • Most diverse and abundant component of the plankton community • Only a small portion of marine virus diversity has been isolated and described • Composition and structure are dependant on seasonality, the degree of stratification of the water column, and other factors related to geographic location.
Marine Health – positive and negative influences • Global Carbon Cycle Why Are They Important?
Influence on Marine Health • Control of bacterial and algal populations • Microbial Food Web & Nutrient cycling • CO2 cycle • Microbial Diversity
Role in Microbial Food Webs Products of cell lysis: • Macromolecules • Cell organelles • Virus particles
Influence on Structure and Diversity of Aquatic Microbial Communities • Cell Predation Limiting Specific Bacteria and Phytoplankton Populations • Lateral and Horizontal Gene Transfer
An Important Role in the Deep-Sea biogeochemical cycles • Viral production in deep-sea benthic ecosystems worldwide is extremely high • Viral infections are responsible for the abatement of 80% of prokaryotic heterotrophic production
Viruses on the Sea Floor Photo from Monterey Bay Aquarium Research Institute (MBARI)
Increasing Marine Stresses • Transfer of invasive, non-native, microbial constituents from one region to another • Pollution • Outbreak of waterborne disease • Loss of habitat • Overharvesting
Implications for Future Research • The processes involved with with viruses and nutrient cycling need to be examined • The effects of global warming have placed special emphasis on understanding the biogeochemical cycling of carbon and nitrogen • Determination of how the physiology and ecology of planktonic organisms affects global carbon and nitrogen cycling may improve our ability to predict and perhaps remediate the ecological impacts of human related carbon and nitrogen release
The Potential for New Discoveries • A marine virus has been found with a gigantic genome that contains compounds that might be used in anti-ageing and cancer-inhibiting therapies • This virus is known to infect a marine algae species that is important in taking billions of tonnes of carbon dioxide from the atmosphere and is thought to control climate through the production of a gas (dimethyl sulfide) that helps form clouds
Implications for Marine Management • Through cycles of infection, replication and host cell lysis, phages impact multiple pathways and processes involved in the population ecology and functioning of marine environments as a whole • Scientists need to better understand the function of marine viruses in order to model the future effects of climate change and other global changes as well as to find new discoveries in medicine and microbiolog