University of British
Columbia, Departments of
Earth and Ocean Sciences,
Botany, and Microbiology
and Immunology, 1461
BioSciences, 6270 University
Boulevard, Vancouver, British
Columbia V6T 1Z4, Canada.
The portion of the Earth in
which viruses occur or which is
affected by viruses; sometimes
called the viriosphere.
Describes an organism that
uses organic compounds for
both energy and growth.
Describes an organism that
uses inorganic compounds for
both energy and growth. In the
oceans phytoplankton are the
most common autotrophs.
Marine viruses — major players in the
Curtis A. Suttle
Abstract | Viruses are by far the most abundant ‘lifeforms’
in the oceans and are the reservoir
of most of the genetic diversity in the sea. The estimated 10
viruses in the ocean, if stretched
end to end, would span farther than the nearest 60 galaxies. Every second, approximately
viral infections occur in the ocean. These infections are a major source of mortality, and
cause disease in a range of organisms, from shrimp to whales. As a result, viruses influence
the composition of marine communities and are a major force behind biogeochemical cycles.
Each infection has the potential to introduce new genetic information into an organism or
progeny virus, thereby driving the evolution of both host and viral assemblages. Probing this
vast reservoir of genetic and biological diversity continues to yield exciting discoveries.
The oceans cover more than 70% of the Earth’s surface.
They control the climate, provide a significant amount
of the protein that is consumed globally and produce
approximately half of the Earth’s oxygen. Microorganisms
are a major force behind the nutrient and energy cycles
in the world’s oceans and constitute more than 90% of
the living biomass in the sea. It is estimated that viruses
kill approximately 20% of this biomass per day. As well
as being agents of mortality, viruses are one of the largest
reservoirs of unexplored genetic diversity on the Earth.
is probably inclusive of every environ-
ment on the Earth, from the atmosphere to the deep bio-
sphere. However, nowhere is the importance of viruses
more evident than in the world’s oceans. The observation
that millions of virus-like particles are present in every
millilitre of ocean water
, coupled with evidence that
viruses are substantial agents of mortality in
, has focused attention on the
enormous underestimation of the effects of viral infec-
tion in the sea. It has become apparent that viruses are
major players in the mortality of marine microorganisms
and, consequently, affect nutrient and energy cycles as
well as the structure of microbial communities.