Microbial Ecology

, Volume 17, Issue 3, pp 237–250 | Cite as

Comparison of three techniques for administering radiolabeled substrates to sediments for trophic studies: Incorporation by microbes

  • Fred C. Dobbs
  • James B. Guckert
  • Kevin R. Carman


Three principal methods have been used to administer substrates to sediments: injection, porewater replacement, and slurry. Here we assess how each of these techniques affects incorporation of radiolabels into macromolecules of marine sedimentary microbes. Eighty-five cores of intertidal sand were collected in a randomized-block, factorial design. One set of cores received14C-bicarbonate/3H-thymidine and was incubated in the light; another set received14C-acetate/3H-thymidine and was incubated in the dark. Following a 5-hour incubation, sediments were analyzed for incorporation of radiolabel into lipid fractions (neutral, glyco-, and polar) and DNA. The three methods of isotope administration were also applied to cores subsequently analyzed for polar lipid phosphates and phospholipid fatty-acid (PLFA) profiles. In general, incorporation was greatest when injections were made, consistent with the prediction that incorporation would decrease as specific activity of the radiolabeled substrate was diminished by dilution. The ratio of14C from acetate incorporated into polar and glycolipid fractions indicated that a significant disturbance accompanied the porewater and slurry techniques. Substantial amounts of3H were recovered in the neutral-lipid fraction, indicating that thymidine was catabolized by sedimentary microbes and tritiated products were incorporated by eukaryotes. There were no significant differences in PLFA profiles or estimates of microbial biomass among methods or controls. Incorporation of3H into DNA was similar with all combinations of methods and radiocarbon substrates.14C was extensively incorporated into DNA, indicating that photoautotrophs and heterotrophs utilized radiocarbon from bicarbonate and acetate, respectively, for de novo synthesis of DNA. Injection is suggested as the method of choice, as it presents more flexibility in its application than porewater replacement and disturbs the consortia of gradients in sediments to a significantly lesser degree than porewater replacement and slurry.


Microbe Thymidine Microbial Biomass Polar Lipid Lipid Fraction 
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  1. 1.
    Brock TD (1987) The study of microorganisms in situ: progress and problems. In: Fletcher M, Gray TRG, Jones JG (eds) Ecology of microbial communities. Cambridge University Press, pp 1–17Google Scholar
  2. 2.
    Carman KR, Thistle D (1985) Microbial food partitioning by three species of benthic copepods. Mar Biol 88:143–148Google Scholar
  3. 3.
    Carman KR, Dobbs FC, Guckert JB (1988) Consequences of thymidine catabolism for estimates of bacterial production: an example from a coastal marine sediment. Limnol Oceanogr 33:1595–1606Google Scholar
  4. 4.
    Carman KR, Dobbs FC, Guckert JB (in press) Comparison of Three Techniques for Administering Radiolabeled Substrates to Sediments for Trophic Studies: Uptake of Label by Harpacticoid Copepods. Mar BiolGoogle Scholar
  5. 5.
    Christian RR, Wiebe WJ (1979) Three experimental regimes in the study of sediment microbial ecology. In: Litchfield CD, Seyfried PL (eds) Methodology for biomass determinations and microbial activities in sediments. American Society for Testing and Materials, pp 148–155Google Scholar
  6. 6.
    Craven DB, Karl DM (1984) Microbial RNA and DNA synthesis in marine sediments. Mar Biol 83:129–139Google Scholar
  7. 7.
    Deming JW, Colwell RR (1985) Observations of barophilic microbial activity in samples of sediment and intercepted particulates from the Demerara Abyssal Plain. Appl Environ Microbiol 50:1002–1006Google Scholar
  8. 8.
    Dobbs, FC, Guckert JB (1988) Microbial food resources of the macrofaunal-deposit feederPtychodera bahamensis (Hemichordata: Enteropneusta). Mar Ecol Prog Ser 45:127–136Google Scholar
  9. 9.
    Findlay RH, White DC (1987) A simplified method for bacterial nutritional status based on the simultaneous determination of phospholipid and endogenous storage lipid poly-B-hy-droxyalkanoate. J Microbiol Meth 6:113–120Google Scholar
  10. 10.
    Findlay RH, Pollard PC, Moriarty DJW, White DC (1985) Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifact. Can J Microbiol 31: 493–498PubMedGoogle Scholar
  11. 11.
    Gehron MJ, White DC (1983) Sensitive assay of phospholipid glycerol in environmental samples. J Microbiol Meth 1:23–32Google Scholar
  12. 12.
    Guckert JB, Antworth CP, Nichols PD, White DC (1985) Phospholipid, ester-linked fatty acid profiles as reproducible assays for changes in prokaryotic community structure of estuarine sediments. FEMS Microbiol Ecol 31:147–158Google Scholar
  13. 13.
    Hall KJ, Kleiber PM, Yesaki I (1972) Heterotrophic uptake of organic solutes by microorganisms in the sediment. Mem Ist Ital Idrobiol 29(suppl):441–471Google Scholar
  14. 14.
    Harrison MJ, Wright RT, Morita RY (1971) Method for measuring mineralization in lake sediments. Appl Microbiol 21:698–702PubMedGoogle Scholar
  15. 15.
    Henriksen K (1980) Measurement of in situ rates of nitrification in sediments. Microb Ecol 6:329–337Google Scholar
  16. 16.
    Jansson BO (1967) The significance of grain size and pore water content for the interstitial fauna of sandy beaches. Oikos 18:311–322Google Scholar
  17. 17.
    Jones JG, Simon BM (1984) Measure of microbial turnover of carbon in anoxic freshwater sediments: cautionary comments. J Microbiol Meth 3:47–55Google Scholar
  18. 18.
    Jørgensen BB (1978) A comparison of methods for the quantification of bacterial sulfate reduction in coastal marine sediments. I. Measurement with radiotracer techniques. Geomicrobiol J 1:11–27Google Scholar
  19. 19.
    Jørgensen BB, Fenchel T (1974) The sulfur cycle of a marine sediment model system. Mar Biol 24:189–201Google Scholar
  20. 20.
    Jørgensen BB, Sørensen J (1985) Seasonal cycles of O2, NO3 and SO4 2− reduction in estuarine sediments: the significance of an NO3 reduction maximum in spring. Mar Ecol Prog Ser 24: 65–74Google Scholar
  21. 21.
    Kemp PF (1987) Potential impact on bacteria of grazing by a macrofaunal deposit-feeder, and the fate of bacterial production. Mar Ecol Prog Ser 36:151–161Google Scholar
  22. 22.
    Kirk RE (1982) Experimental design: procedures for the behavioral sciences, 2nd ed. Brooks/Cole Publishing CompanyGoogle Scholar
  23. 23.
    Meyer-Reil L-A (1978) Uptake of glucose by bacteria in the sediment. Mar Biol 44:293–298Google Scholar
  24. 24.
    Meyer-Reil L-A (1986) Measurement of hydrolytic activity and incorporation of dissolved organic substrates by microorganisms in marine sediments. Mar Ecol Prog Ser 31:143–149Google Scholar
  25. 25.
    Meyer-Reil L-A, Faubel A (1980) Uptake of organic matter by meiofauna organisms and interrelationships with bacteria. Mar Ecol Prog Ser 3:251–256Google Scholar
  26. 26.
    Montagna PA (1984) In situ measurement of meiobenthic grazing rates on sediment bacteria and edaphic diatoms. Mar Ecol Prog Ser 18:119–130Google Scholar
  27. 27.
    Montagna PA, Bauer JE (1988) Partitioning radiolabeled thymidine uptake by bacteria and meiofauna using blocks and poisons in benthic feeding studies. Mar Biol 98:101–110Google Scholar
  28. 28.
    Moriarty DJW, White DC, Wassenberg TJ (1985) A convenient method for measuring rates of phospholipid synthesis in seawater and sediments: its relevance to the determination of bacterial productivity and the disturbance artifacts introduced by measurements. J Microbiol Meth 3:321–330Google Scholar
  29. 29.
    Murray RE, Cooksey KE, Priscu JC (1986) Stimulation of bacterial RNA synthesis by algal exudates in attached algal-bacterial consortia. Appl Environ Microbiol 52:1177–1182Google Scholar
  30. 30.
    Novitsky JA (1983) Microbial activity at the sediment-water interface in Halifax Harbor, Canada. Appl Environ Microbiol 45:1761–1766Google Scholar
  31. 31.
    Novitsky JA (1987) Microbial growth rates and biomass production in a marine sediment: evidence for a very active but mostly nongrowing community. Appl Environ Microbiol 53: 2368–2372Google Scholar
  32. 32.
    Novitsky JA, Kepkay PE (1981) Patterns of microbial heterotrophy through changing environments in a marine sediment. Mar Ecol Prog Ser 4:1–7Google Scholar
  33. 33.
    Servais P, Martinez J, Billen G, Vives-Rego J (1987) Determining [3H]thymidine incorporation into bacterioplankton DNA: improvement of the method by DNase treatment. Appl Environ Microbiol 53:1977–1979Google Scholar
  34. 34.
    Ward TE, Frea JI (1979) Estimation of microbial activities in lake sediments by measurement of sediment gas evolution. In: Litchfield CD, Seyfried PL (eds) Methodology for biomass determinations and microbial activities in sediments. American Society for Testing and Materials, pp 156–166Google Scholar
  35. 35.
    White DC, Davis WM, Nickels JS, King JD, Bobbie RJ (1979) Determination of the sedimentary microbial biomass by extractible lipid phosphate. Oecologia (Berl) 40:51–62Google Scholar
  36. 36.
    White DC, Bobbie RJ, King JD, Nickels JS, Amoe P (1979) Lipid analysis of sediments for microbial biomass and community structure. In: Litchfield CD, Seyfried PL (eds) Methodology for biomass determinations and microbial activities in sediments. American Society for Testing and Materials, pp 87–103Google Scholar

Copyright information

© Springer-Verlag New York Inc. 1989

Authors and Affiliations

  • Fred C. Dobbs
    • 1
  • James B. Guckert
    • 2
  • Kevin R. Carman
    • 1
  1. 1.Department of OceanographyFlorida State UniversityTallahasseeUSA
  2. 2.Institute for Applied MicrobiologyUniversity of TennesseeKnoxvilleUSA

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