52
Conclusions
Heterotrophic bacterioplankton in seawater appear to be well
adapted to the nutrient regime they encounter. Their small cell size
and periplasmic proteins may facilitate nutrient uptake, whereas the
presence of mUltiple or multiphasic transport systems impart metabolic
flexibility in a fluctuating nutrient environment. Chemoreception and
motility are likely to be of fundamental importance for marine
bacterioplankton. Little quantitative information exists regarding
these behavioral responses of marine bacteria in situ, and this needs
to be studied. Although this discussion applies mainly to the euphotic
zone of the sea, some general principles may apply to the deeper parts
of the sea as well. However, we know little about the mechanisms of
UDOM production in the deeper parts of the water column, and this is a
fundamental question in determining the bacteria-organic matter interactions in the deep sea. Sinking organic particles are generally
considered the main source of UDOM, and it is likely that exoenzymes
of particle-associated bacteria play a central role in their
utilization.
References
Ammerman JW and Azam F (1981) Dissolved cyclic adenosine monophosphate
(cAMP) in the sea and uptake of cAMP by marine bacteria. Mar.
Ecol. Prog. Ser. 5 : 85-89.
Ammerman JW and Azam F (1982) Uptake of cyclic AMP by natural
populations of marine bacteria. Appl. Environ. Microbiol. 43
869-876.
Ammerman JW, Fuhrman JA, Hagstrom A, and Azam F (in press) Bacterioplankton growth in seawater.
I. Growth kinetics and cellular
characteristics in seawater cultures. Mar. Ecol. Prog. Ser.
Azam F, Fenchel T, Field JG, Gray JS, Meyer-Reil LA and Thingstad F
(1983) The ecological role of water-column microbes in the sea.
Mar. Ecol. Prog. Ser. 10 : 257-263.
Azam F and Ammerman JW (1984) Cycling of organic matter by bacterioplankton in pelagic marine ecosystems: microenvironmental
considerations. In: Fasham MJ (ed.) Flows of energy and
materials in marine ecosystems. Theory and practice. NATO-ARI,
May 1982 (in press)
Azam F and Hodson RE (1981) Multiphasic kinetics for D-glucose uptake
by assemblages of natural marine bacteria. Mar. Ecol. Prog. Ser.
6 : 213-222.
Bell WH and Mitchell R (1972) Chemotactic and growth responses of
marine bacteria to algal extracellular products. Biol. Bull.
143 : 265-277.
Conclusions
Heterotrophic bacterioplankton in seawater appear to be well
adapted to the nutrient regime they encounter. Their small cell size
and periplasmic proteins may facilitate nutrient uptake, whereas the
presence of mUltiple or multiphasic transport systems impart metabolic
flexibility in a fluctuating nutrient environment. Chemoreception and
motility are likely to be of fundamental importance for marine
bacterioplankton. Little quantitative information exists regarding
these behavioral responses of marine bacteria in situ, and this needs
to be studied. Although this discussion applies mainly to the euphotic
zone of the sea, some general principles may apply to the deeper parts
of the sea as well. However, we know little about the mechanisms of
UDOM production in the deeper parts of the water column, and this is a
fundamental question in determining the bacteria-organic matter interactions in the deep sea. Sinking organic particles are generally
considered the main source of UDOM, and it is likely that exoenzymes
of particle-associated bacteria play a central role in their
utilization.
References
Ammerman JW and Azam F (1981) Dissolved cyclic adenosine monophosphate
(cAMP) in the sea and uptake of cAMP by marine bacteria. Mar.
Ecol. Prog. Ser. 5 : 85-89.
Ammerman JW and Azam F (1982) Uptake of cyclic AMP by natural
populations of marine bacteria. Appl. Environ. Microbiol. 43
869-876.
Ammerman JW, Fuhrman JA, Hagstrom A, and Azam F (in press) Bacterioplankton growth in seawater.
I. Growth kinetics and cellular
characteristics in seawater cultures. Mar. Ecol. Prog. Ser.
Azam F, Fenchel T, Field JG, Gray JS, Meyer-Reil LA and Thingstad F
(1983) The ecological role of water-column microbes in the sea.
Mar. Ecol. Prog. Ser. 10 : 257-263.
Azam F and Ammerman JW (1984) Cycling of organic matter by bacterioplankton in pelagic marine ecosystems: microenvironmental
considerations. In: Fasham MJ (ed.) Flows of energy and
materials in marine ecosystems. Theory and practice. NATO-ARI,
May 1982 (in press)
Azam F and Hodson RE (1981) Multiphasic kinetics for D-glucose uptake
by assemblages of natural marine bacteria. Mar. Ecol. Prog. Ser.
6 : 213-222.
Bell WH and Mitchell R (1972) Chemotactic and growth responses of
marine bacteria to algal extracellular products. Biol. Bull.
143 : 265-277.