mers are immediately incorporated by microorganisms. In this case the relation between
H R and TR would be equal to the relation between the pool of directly available polymers
and the pool of monomers. In the present study we found that in a polluted inshore area
the pool size of MUF-leucine substrate analogues (available protein pool) was about 6
times greater than the leucine pool. In offshore waters the corresponding pools were
approx. of the same size. This means that the pool of available polymers, in the sense as it
is used here, and the pool of the corresponding monomers is within the same order of
magnitude.
It is suggested that besides exudation of phytoplankton, products resulting from extracellular enzymatic decomposition of soluble polymers by bacteria serve as an important
source for bacterial nutrition in natural environments. The enzymatic hydrolyzation rate
is strong enough to balance the pool of soluble monomers. It is expected that in
sub-euphotic zones and at the bottom of water bodies extracellular enzymatic hydrolysis
of polymers and oligomers may be even a key factor for the existence of heterotrophic
bacteria.
BAUERFEIND S., 1982. Versuche zum Abbau von Plankton und Detritusmaterial durch natürliche Bakterienpopulationen der Schlei und der Ostsee. Thesis, Univ. of Kiel: 115 pp.
DEGENS E.T., 1970. Molecular nature of nitrogeneous compounds in sea water and recent sediments. In: Hood
(ed.) : Organic matter in natural waters. Occ. Publ. 1, Univ. of Alaska'. 77 - 106.
GOCKE K., 1976. Respiration von gelösten organischen Verbindungen durch natürliche Mikroorganismenpopulationen. Ein Vergleich zwischen verschiedenen Biotopen. Mar. Biol. 35: 375 - 383.
GRASSHOFF K., 1976. Methods of seawater analysis. Verlag Chemie, Weinheim, New York: 317 pp.
HAMA T and N. HANDA 1980. Molecular weight distribution and characterization of dissolved organic matter
from lake waters. Arch. Hydrobiol. 90: 105 - 1230.
HOLLIBAUGH J.T. and F. AZAM, 1983. Microbial degradation of dissolved proteins in seawater. Limnol.
Oceanogr. 28: 1104 -1116.
HOPPE H.-G., 1978. Relations between active bacteria and heterotrophic potential in the sea. Netherlands J. Sea
Res. 13: 78 - 98.
HOPPE H.-G., 1983. Significance of exoenzymatic activities in the ecology of brackish water: measurements by
means of methylumbelliferyl-substrates. Mar. Ecol. Prog. Ser. 11: 299 - 308.
KIM S.J. and H.-G. HOPPE, 1984. Microbial extracellular enzyme detection on agar plates by means of
fluorogenic methylumbelliferyl-substrates. This volume.
KJELLEBERG S. and N.HAKANSSON, 1977. Distribution of lipolytic, proteolytic, and amylolytic marine bacteria
between the lipid film and the subsurface water. Mar. Biol. 39: 103 - 109.
KRAMBECK C., 1979. Applicability and limitation of the Michaelis-Menten equation in microbial ecology. Arch.
Hydrobiol. 12: 64 - 76.
PETTERSSON K. and M. JANSSON, 1978. Determination of phosphatase activity in lake water - a study of
methods. Verh. int. Verein. theor. angew. Limnol 20: 1226 - 1230.
SCOR-UNESCO, 1966. Determination of photosynthetic pigments. (In: Monographs on oceanographic methodology), Rep. Work. Group No. 17, UNESCO, 69 pp.
SIEBURTH J.McN., 1971. Distribution and activity of oceanic bacteria. Deep-Sea Res. 18 : 1111 - 1121.
SOMVILLE M., 1984. Measurement and study of substrate specificity of exoglucosidase in natural water. Appl.
Environ. Microbiol. 48: 1181-1185.
SOMVILLE M and G BILLEN, 1983. A method for determining exoproteolytic activity in natural waters. Limnol.
Oceanogr. 28: 190 - 193.
127
H R and TR would be equal to the relation between the pool of directly available polymers
and the pool of monomers. In the present study we found that in a polluted inshore area
the pool size of MUF-leucine substrate analogues (available protein pool) was about 6
times greater than the leucine pool. In offshore waters the corresponding pools were
approx. of the same size. This means that the pool of available polymers, in the sense as it
is used here, and the pool of the corresponding monomers is within the same order of
magnitude.
It is suggested that besides exudation of phytoplankton, products resulting from extracellular enzymatic decomposition of soluble polymers by bacteria serve as an important
source for bacterial nutrition in natural environments. The enzymatic hydrolyzation rate
is strong enough to balance the pool of soluble monomers. It is expected that in
sub-euphotic zones and at the bottom of water bodies extracellular enzymatic hydrolysis
of polymers and oligomers may be even a key factor for the existence of heterotrophic
bacteria.
BAUERFEIND S., 1982. Versuche zum Abbau von Plankton und Detritusmaterial durch natürliche Bakterienpopulationen der Schlei und der Ostsee. Thesis, Univ. of Kiel: 115 pp.
DEGENS E.T., 1970. Molecular nature of nitrogeneous compounds in sea water and recent sediments. In: Hood
(ed.) : Organic matter in natural waters. Occ. Publ. 1, Univ. of Alaska'. 77 - 106.
GOCKE K., 1976. Respiration von gelösten organischen Verbindungen durch natürliche Mikroorganismenpopulationen. Ein Vergleich zwischen verschiedenen Biotopen. Mar. Biol. 35: 375 - 383.
GRASSHOFF K., 1976. Methods of seawater analysis. Verlag Chemie, Weinheim, New York: 317 pp.
HAMA T and N. HANDA 1980. Molecular weight distribution and characterization of dissolved organic matter
from lake waters. Arch. Hydrobiol. 90: 105 - 1230.
HOLLIBAUGH J.T. and F. AZAM, 1983. Microbial degradation of dissolved proteins in seawater. Limnol.
Oceanogr. 28: 1104 -1116.
HOPPE H.-G., 1978. Relations between active bacteria and heterotrophic potential in the sea. Netherlands J. Sea
Res. 13: 78 - 98.
HOPPE H.-G., 1983. Significance of exoenzymatic activities in the ecology of brackish water: measurements by
means of methylumbelliferyl-substrates. Mar. Ecol. Prog. Ser. 11: 299 - 308.
KIM S.J. and H.-G. HOPPE, 1984. Microbial extracellular enzyme detection on agar plates by means of
fluorogenic methylumbelliferyl-substrates. This volume.
KJELLEBERG S. and N.HAKANSSON, 1977. Distribution of lipolytic, proteolytic, and amylolytic marine bacteria
between the lipid film and the subsurface water. Mar. Biol. 39: 103 - 109.
KRAMBECK C., 1979. Applicability and limitation of the Michaelis-Menten equation in microbial ecology. Arch.
Hydrobiol. 12: 64 - 76.
PETTERSSON K. and M. JANSSON, 1978. Determination of phosphatase activity in lake water - a study of
methods. Verh. int. Verein. theor. angew. Limnol 20: 1226 - 1230.
SCOR-UNESCO, 1966. Determination of photosynthetic pigments. (In: Monographs on oceanographic methodology), Rep. Work. Group No. 17, UNESCO, 69 pp.
SIEBURTH J.McN., 1971. Distribution and activity of oceanic bacteria. Deep-Sea Res. 18 : 1111 - 1121.
SOMVILLE M., 1984. Measurement and study of substrate specificity of exoglucosidase in natural water. Appl.
Environ. Microbiol. 48: 1181-1185.
SOMVILLE M and G BILLEN, 1983. A method for determining exoproteolytic activity in natural waters. Limnol.
Oceanogr. 28: 190 - 193.
127