70. L. Yu, Y.G. Hu, R.S. Lon, H.L. Zhang, Z.D. Nan, and F.H. Li, “The Effects of Environmental Conditions on the Growth of Petroleum Microbes by Microcalorimetry,” Thermochimica Acta 359:95-101, 2000.

71. T.T. Packard, “Measurement of Electron Transport Activity of Microplankton,” in H.W. Jannasch and P.J. LeB. Williams (eds.), Advances in Aquatic Microbiology, Vol. 3, Academic Press, New York, 1985, pp. 208-281.

72. M.L. Fogel and L.A. Cifuentes, “Isotope Fractionation During Primary Production,” in S.A. Macko and M.H. Engel (eds.), Organic Geochemistry, Principles and Applications, Plenum Press, New York, 1993, pp. 73-100.

73. B.M. Jakosky, “Martian Stable Isotopes: Volatile Evolution, Climate Change and Exobiological Implications,” Origin of Life andEvolution of the Biosphere 29:47-57, 1999.

74. P. Stapp, G.A. Polls, and F.S. Pinero, “Stable Isotopes Reveal Marine and El Niño Effects on Island Food Webs,” Nature 401:467-469, 1999.

75. H. Bothe, G. Jost, M. Schloter, B.B. Ward, and K.-P. Witzel, “Molecular Analysis of Ammonia and Denitrification in Natural Environments, ” FEMS Microbiol. Rev. 24:673-690, 2000.

76. D.G. Capone, “The Marine Microbial Nitrogen Cycle,” in D.L. Kirchman (ed.), Microbial Ecology of the Oceans, John Wiley & Sons, New York, 2000, pp. 455-493.

77. M.V. Orellana and M.J. Perry, “Optimization of an Immunofluorescent Assay of the Internal Enzyme Ribulose-1,5-Bisphosphate Carboxylase (Rubisco) in Single Phytoplankton Cells,” J. Phycol. 31:785-794, 1995.

78. B.C. Crump and J.A. Baross, “Particle-Attached Bacteria and Heterotrophic Plankton Associated with the Columbia River Estuarine Turbidity Maxima,” Mar. Ecol. Prog. Ser. 138:265-273, 1996.

79. H.-G. Hoppe, “Use of Fluorogenic Model Substrates for Extracellular Enzyme Activity (EEA) Measurement of Bacteria,” in P.F. Kemp, B.F. Sherr, E.B. Sherr, and J.J. Cole (eds.), Handbook of Methods in Aquatic Microbial Ecology, Lewis Publishers, Boca Raton, Fla., 1993, pp. 423-431.

80. M. Unanue, B. Ayo, M. Agis, D. Slezak, G.J. Herndl, and J. Iriberri, “Ectoenzymatic Activity and Uptake of Monomers in Marine Bacterioplankton Described by a Biphasic Kinetic Model,” Microbial Ecology 37:36-48, 1999.

81. Y.-A. Vetter and J.W. Deming, “Extracellular Enzyme Activity in the Arctic Northeast Water Polynya, ” Mar. Ecol. Prog. Ser. 114:23-34, 1994.

82. R. Amann and W. Ludwig, “Ribosomal RNA-Targeted Nucleic Acid Probes for Studies in Microbial Ecology,” FEMS Microbiol. Rev. 24:555-565, 2000.

83. S.L. Walker, T.F. Brocklehurst, and J.W.T. Wimpenny, “Adenylates and Adenylate-Energy Charge in Submerged and Planktonic Cultures of Salmonella enteritides and Salmonella typhimurium,” Int. J. Food Microbiol. 44:107-113, 1998.

84. W.J. Wiebe and K. Bancroft, “Use of the Adenylate Energy Charge Ratio to Measure the Growth State of Natural Microbial Communities,” Proc. Natl. Acad. Sci. (U.S.A.) 72:2112-2115, 1975.

85. E.R. Pecke and R.R. Colwell, “Application of a Direct Microscopic Method for Enumeration of Substrate-Responsive Marine Bacteria,” Can. J. Microbiol. 27:1071-1075, 1981.

86. P.S. Tabor and R.A. Neihof, “Direct Determination of Activities for Microorganisms of Chesapeake Bay Population,” Appl. Environ. Microbiol. 48:1012-1019, 1984.

87. J.W. Ammerman and F. Azam, “Characterization of Cyclic AMP Transport by Marine Bacteria,” Appl. Environ. Microbiol. 53:2963-2966, 1987.

88. R. Bachofen and A. Schenk, “Quorum Sensing Autoinducers: Do They Play a Role in Natural Microbial Habitats?” Microbiol. Res. 153:61-63, 1998.

89. Space Studies Board, National Research Council, Size Limits of Very Small Microorganisms, Proceedings of a Workshop , National Academy Press, Washington, D.C., 1997.