Light and Temperature

  • Robert G. Wetzel
  • Gene E. Likens


Solar radiation is vital to the metabolism, indeed to the very existence, of freshwater ecosystems. Nearly all energy that drives and controls the metabolism of lakes and streams is derived from solar energy, which is converted biochemically via photosynthesis to potential chemical energy. The photosynthetic synthesis of organic matter occurs within the lake or river (autochthonous) or within the terrestrial drainage basin (allochthonous) and is transported to the aquatic ecosystem in various forms of dissolved and particulate organic matter by “vehicles” for movement [e.g., air, water, animals; cf., Likens and Bormann (1972)]. In addition to direct biological utilization, the absorption of solar energy and its dissipation as heat markedly affect the thermal structure and stratification of water masses and circulation patterns of lakes, reservoirs, and streams. These characteristics in turn have profound effects on nutrient cycling and the distribution of dissolved gases and the biota. The optical properties of fresh waters, therefore, exert important regulatory controls on the physiology and behavior of aquatic organisms.

Light impinging on the urface of water does not penetrate completelyya significant portion is reflected and backscattered [cf., Wetzel (1983) and Exercise 4, p. 45]. Within the water, light is rapidly attenuated with increasing depth by both absorption and scattering mechanisms. Absorption is defined as diminution of light energy with increasing depth by transformation to heat [cf., Westlake (1965)]. Absorption is influenced by the molecular structure of water itself, by particles suspended in the water, and particularly by dissolved organic compounds. The result is a selective absorption and attenuation of light energy with increase in depth, influenced by an array of physical, chemical, and, under certain conditions, biotic properties of the water. These optical properties are dynamic, changing seasonally and over geological time for individual freshwater ecosystems.

Over half of the solar radiation that penetrates into water is absorbed and dissipated as heat. As we will see in subsequent analyses (Exercises 3 and 4), the distribution of this heat is influenced greatly by wind energy. In this exercise, we will evaluate methods for the measurement and description of the distribution of light and temperature in water.


Photosynthetically Active Radiation Secchi Disc Surface Irradiance Total Irradiance Secchi Disc Transparency 
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  1. Åberg, B. and W. Rodhe. 1942. Über die Milieufaktoren in einigen südschwedischen Seen. Symbol. Bot. Upsalien. 5(3). 256 pp.Google Scholar
  2. Baker, A.L. and A.J. Brook. 1971. Optical density profiles as an aid to the study of micro-stratified phytoplankton populations in lakes. Arch. Hydrobiol. 69:214–233.Google Scholar
  3. Baker, A.L., K.K. Baker, and P.A. Tyler. 1985. Fine-layer depth relationships of lakewater chemistry, planktonic algae and photosynthetic bacteria in meromictic Lake Fidler, Tasmania. Freshwat. Biol. 15:735–747.CrossRefGoogle Scholar
  4. Beeton, A.M. 1958. Relationship between Secchi disc readings and light penetration in Lake Huron. Trans. Amer. Fish. Soc. 87:13–79.CrossRefGoogle Scholar
  5. Birge, E.A. 1915. The heat budgets of American and European lakes. Trans. Wis. Acad. Sei. Arts Lett. 18(Part 1):166–213.Google Scholar
  6. Birge, E.A. 1916. The work of the wind in warming a lake. Trans. Wis. Acad. Sei. Arts Lett. 18(Part 2):341–391.Google Scholar
  7. Elster, H.J. and M Štěpánek. 1967. Eine neue Modifikation der Secchischeibe. Arch. Hydrobiol. (Suppl.) 33:101–106.Google Scholar
  8. Hutchinson, G.E. 1957. A treatise on Limnology. I. Geography, Physics, and Chemistry. Wiley, New York. 1015 pp.Google Scholar
  9. Johnson, N.M., G.E. Likens, and J.S. Eaton. 1985. Stability, circulation and energy flux in Mirror Lake. pp. 108–127. In G.E. Likens, Editor. An Ecosystem Approach to Aquatic Ecology. Mirror Lake and Its Environment. Springer-Verlag, New York.Google Scholar
  10. Karentz, D. and Bothers. 1994. Impact of UV-B radiation on pelagic freshwater ecosystems: Report of working group on bacteria and phytoplankton. Arch. Hydrobiol. Beih. Ergebn. Limnol. 43:31–69.Google Scholar
  11. Kerr, J.B. and C.T. McElroy. 1993. Evidence for large upward trends in ultraviolet-B radiation linked to ozone depletion. Science 262:1032–1034.PubMedCrossRefGoogle Scholar
  12. Kirk, J.T.O. 1094a. Optics of UV-B radiation in natural waters. Arch. Hydrobiol. Beih. Ergebn. Limnol. 43:1–16.Google Scholar
  13. Kirk, J.T.O.1994b. Light and photosynthesis in aquatic ecosystems. 2nd Ed. Cambridge Univ. Press, Cambridge, England.CrossRefGoogle Scholar
  14. Likens, G.E. and F.H. Bormann. 1972. Nutrient cycling in ecosystems, pp. 25–67. In J. Wiens, Editor. Ecosystem Structure and Function. Oregon State Univ. Corvallis.Google Scholar
  15. Morris, D.P., H. Zagarese, C.E. Williamson, E.G. Balseiro, B.R. Hargreaves, B. Modenutti, R. Moeller, Arid C. Queimalinos. 1995. The attenuation of solar UV radiation in lakes and the role of dissolved organic carbon. Limnol. Oceanogr. 40:1381–1391.CrossRefGoogle Scholar
  16. Rich, P.H. and R.G Wetzel. 1969. A simple, sensitive underwater photometer. Limnol. Oceanogr. 14:611–613.CrossRefGoogle Scholar
  17. Sauberer, F. 1962. Empfehlungen für die Durchfuhrung von Strahlungsmessungen an und in Gewässern. Mitt. Int. Ver. Limnol. 11. 77 pp.Google Scholar
  18. Smith, R.C. and WH. Wilson, Jr. 1972. Photon scalar irradiance. Appl. Optics 11:934–938.CrossRefGoogle Scholar
  19. Smith, R.C., J.E. Tyler, and CR. Goldman. 1973. Optical properties and color of Lake Tahoe and Crated Lake. Limnol. Oceanogr. 18:189–199.CrossRefGoogle Scholar
  20. Štěpánek, M. 1959. Limnological study of the reservoir Sedlice near Zeliv. IX. Transmission and transparency of water. Sci. Pap. Inst. Chem. Technol., Prague, Fac. Technol. Fuel Water 3(Part 2):363–430.Google Scholar
  21. Stewart, K.M., K.W. Maleug, and P.E. Sager. 1965. Comparative winter studies on dimictic and meromictic lakes. Verh. Int. Ver. Limnol. 16:47–57.Google Scholar
  22. Strickland, J.D.H. 1958. Solar radiation penetrating the ocean. A review of requirements, data and methods of measurement, with particular reference to photosynthetic productivity. J. Fish. Res. Bd. Canada 15:453–493.CrossRefGoogle Scholar
  23. Tailing, J.F. 1957. Photosynthetic characteristics of some freshwater plankton diatoms in relation to underwater radiation. New Phytol. 56:29–50.CrossRefGoogle Scholar
  24. Tyler, J.E. 1968. The Secchi disc. Limnol. Oceanogr. 13:1–6.CrossRefGoogle Scholar
  25. Welch, P.S. 1948. Limnological Methods. Blankiston, Philadelphia. 381 pp.Google Scholar
  26. Westlake, D.F. 1965. Some problems in the mesurement of radiation under water: A review. Photochern. Photobiol. 4:849–868.CrossRefGoogle Scholar
  27. Wetzel, R.G. 1983. Limnology 2nd Ed. Saunders Coll., Philadelphia. 858 pp.Google Scholar
  28. Wetzel, R.G. 1999. Limnology: Lake and River Ecosystems. 3rd Ed. Academic Press, San Diego (in press).Google Scholar
  29. Wetzel, R.G., P.G. Hatcher, and T.S. Bianchi. 1995. Natural photolysis of ultraviolet irradiance of recalcitrant dissolved organic matter to simple substrates for rapid bacterial metabolism. Limnol. Oceanogr. 40:1369–1380.CrossRefGoogle Scholar
  30. Whitney, L.V. 1937. Microstratification of the waters of inland lakes in summer. Science 85:224–225.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2000

Authors and Affiliations

  • Robert G. Wetzel
    • 1
  • Gene E. Likens
    • 2
  1. 1.Department of Biology, College of Arts and SciencesUniversity of AlabamaTuscaloosaUSA
  2. 2.Institute of Ecosystem Studies, Cary ArboretumThe New York Botanical GardenMillbrookUSA

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