Do Viruses Control the Oceans?

The general issue which Curtis Suttle and his colleagues are exploring

is stated in title of his article : “Do Viruses Control the Oceans?” He is

referring here to the research he has been involved with, investigating the

role that viruses play in the life and death of unicellular planktonic organisms,

and the wider implications of this oceanic dynamic.

Based on research from the State University of New York at Stony Brook,

and the University of Bergen in Norway, which showed that viruses were

ten times more plentiful in seawater than bacteria (bacterioplankton), Suttle

and his colleagues at the University of British Columbia have explored the

extent of viral infection among the planktonic masses, especially those of

the coastal regions.

By measuring the concentrations of viruses and plankton in coastal waters,

and using mathematical modelling, they concluded that at any given time,

20 percent of the single-celled plankton in the oceans were dying of viral

infection, releasing loads of viral particles as they died. Then, by removing

all viruses from seawater samples and monitoring the effect on the remaining

plankton, they gave evidence that this viral-induced death cycle was essential

for the growth of new planktonic organisms.

Suttle also gives conclusions based on the recent awareness of the pervasive

influence of viruses on the ocean environment. We know that marine viruses

cause die-offs periodically of larger organisms, such as dolphins and seals,

and Suttle questions whether there is possible tranference from terrestrial

viral sources such as cows and dogs. Suttle points out that viruses must play

a significant role in the overall balance of planktonic life, keeping overpopulation

of any one organism in check, and ensuring the diversity of species.

Suttle also leaves us with a significant question, one that may have a profound

bearing on our future here on planet Earth : do marine viruses, and dying plankton,

contribute to greenhouse-effect global warming? There is evidence that some

of the most potent greenhouse gases may be produced in large quantities in the

oceans. There is a converse question which is unstated here… does the industrially

induced global warming contribute to the increase in viral loads in the ocean, and

subsequent planktonic die-offs? Obviously, there awaits very extensive areas

for future research!