Zobell (1946) wrote, “Very little is known concerning the effect of pressure on marine
organisms but certainly it does not exclude life from the abyssal regions of the seas.’’Thus,
he concentrated on the influence of hydrostatic pressure on microorganismal activity in
the following 25 years and developed equipment suitable for this research.
Studies by Morita (1967) showed that deep-sea bacteria usually grow very slowly.
The most important results of these investigations are summarized in the 2 following
articles :
Zobell (1964): “Hydrostatic pressure as a factor affecting the activities of marine
microbes”.
Morita (1967) : “Effects of hydrostatic pressure on marine microorganisms”.
More recent works regarding this theme by Jannasch, Eimhjellen, Wirsen and Farmanfarmaian (1971) were inadvertently triggered by an accident involving the American
research submarine, “Alvin”. It was determined that processes of degradation in the
deep-sea steadily occurred 10-100 times more slowly than at the surface. During the
study of decay by natural deep-sea populations the incubation of substrates at the sea
floor demanded the construction of suitable equipment. Bacteria exhibited varying
degrees of barotolerance.
Whereas the observations by Jannasch and Wirsen (1977) showed that the deep-sea
microflora steadily demonstrates a low metabolic activity, Schwarz, Yayanos and Colwell (1976) measured no lowering of activity of deep-sea amphipod intestinal flora at
700 atm as opposed to 1 atm. Yayanos, Dietz, and Boxtel (1979) also discovered a
barophilic bacterium in these animals’ digestive organs.
Conducted in recent years were microbiological investigations by Karl, Wirsen and
Jannasch (1980) at 2 550 m in an area of Pacific hydrothermal vents near the Galapagos
Islands, where the basis of nourishment for a large animal population is provided by
chemoautotrophic sulfur bacteria, which oxidize H 2 S. The presence of tremendous
amounts of such chemoautotrophic sulfur bacteria indicates that chemosynthetic primary production is the factor permitting the existence of large populations of invertebrates in the vicinity of the hydrothermal vents (Ruby et al. 1981).
Studies of Cavanaugh et al. (1981) indicated that a symbiosis between chemoautotrophic
sulfur bacteria and the pogonophora Riftia pachyptila seems to exist.
Despite the roughly 100 years of research of deep-sea microbiology and the sometimes
extraordinarily interesting findings, our understanding still remains convincingly incomplete. In his essay, “Current status of the microbiology of the deep sea”, Morita (1979)
thus maintained :
“Unfortunately we do not have sufficient data accumulated to make a good assessment of
the microbiology of the deep. It is very dangerous to extrapolate data obtained from one
area of the deep ocean to the entire deep sea”. Bacteria of the surface, for example,
continually enter the deep sea and, unless they are barotolerant, undergo reducted
metabolism due to low temperatures, nutrient limitation and high hydrostatic pressure.
The decisive factor for barotolerant forms is the fulfillment of energy requirements.
Found in nearshore deep-sea trenches are, indeed, allochthonous materials (even wood),
but remaining deep-sea waters contain only minute amounts of sources of energy.
Accordingly, bacterial activity here is extremely low, prohibiting the complete exhaustion
of this energy reserve so necessary to all deep-sea organisms. One such energy source may
19
organisms but certainly it does not exclude life from the abyssal regions of the seas.’’Thus,
he concentrated on the influence of hydrostatic pressure on microorganismal activity in
the following 25 years and developed equipment suitable for this research.
Studies by Morita (1967) showed that deep-sea bacteria usually grow very slowly.
The most important results of these investigations are summarized in the 2 following
articles :
Zobell (1964): “Hydrostatic pressure as a factor affecting the activities of marine
microbes”.
Morita (1967) : “Effects of hydrostatic pressure on marine microorganisms”.
More recent works regarding this theme by Jannasch, Eimhjellen, Wirsen and Farmanfarmaian (1971) were inadvertently triggered by an accident involving the American
research submarine, “Alvin”. It was determined that processes of degradation in the
deep-sea steadily occurred 10-100 times more slowly than at the surface. During the
study of decay by natural deep-sea populations the incubation of substrates at the sea
floor demanded the construction of suitable equipment. Bacteria exhibited varying
degrees of barotolerance.
Whereas the observations by Jannasch and Wirsen (1977) showed that the deep-sea
microflora steadily demonstrates a low metabolic activity, Schwarz, Yayanos and Colwell (1976) measured no lowering of activity of deep-sea amphipod intestinal flora at
700 atm as opposed to 1 atm. Yayanos, Dietz, and Boxtel (1979) also discovered a
barophilic bacterium in these animals’ digestive organs.
Conducted in recent years were microbiological investigations by Karl, Wirsen and
Jannasch (1980) at 2 550 m in an area of Pacific hydrothermal vents near the Galapagos
Islands, where the basis of nourishment for a large animal population is provided by
chemoautotrophic sulfur bacteria, which oxidize H 2 S. The presence of tremendous
amounts of such chemoautotrophic sulfur bacteria indicates that chemosynthetic primary production is the factor permitting the existence of large populations of invertebrates in the vicinity of the hydrothermal vents (Ruby et al. 1981).
Studies of Cavanaugh et al. (1981) indicated that a symbiosis between chemoautotrophic
sulfur bacteria and the pogonophora Riftia pachyptila seems to exist.
Despite the roughly 100 years of research of deep-sea microbiology and the sometimes
extraordinarily interesting findings, our understanding still remains convincingly incomplete. In his essay, “Current status of the microbiology of the deep sea”, Morita (1979)
thus maintained :
“Unfortunately we do not have sufficient data accumulated to make a good assessment of
the microbiology of the deep. It is very dangerous to extrapolate data obtained from one
area of the deep ocean to the entire deep sea”. Bacteria of the surface, for example,
continually enter the deep sea and, unless they are barotolerant, undergo reducted
metabolism due to low temperatures, nutrient limitation and high hydrostatic pressure.
The decisive factor for barotolerant forms is the fulfillment of energy requirements.
Found in nearshore deep-sea trenches are, indeed, allochthonous materials (even wood),
but remaining deep-sea waters contain only minute amounts of sources of energy.
Accordingly, bacterial activity here is extremely low, prohibiting the complete exhaustion
of this energy reserve so necessary to all deep-sea organisms. One such energy source may
19