Raymond L. Lindeman’s landmark paper “The Trophic-Dynamic Aspect of Ecology” described large environmental systems in terms of energy transformation. His work, which led to the development of the field of ecology, proposed a dynamic ecology of “ecosystems,” that is, organic/inorganic processes and their environment functioning as a complex unit, or system.
Raymond L. Lindeman’s scientific paper “The Trophic-Dynamic Aspect of Ecology” was published posthumously in the scientific journal Ecology in October, 1942. The paper described ecosystems in terms of energy transformation, presenting ecological concepts developed from Lindeman’s research on food interactions of organisms in Cedar Bog Lake (or Cedar Creek Bog) in Minnesota. Lindeman integrated food cycle dynamics and community succession. He attempted to construct the first energy budget for an entire ecosystem. The ideas presented in this paper provided a framework for future research on energy flow and nutrient budgets in ecosystems and were the foundation for the development of systems ecology (the study of entire living systems).
Lindeman’s paper was initially rejected on recommendations of Paul S. Welch and Chancey Juday, two well-respected limnological ecologists and reviewers for Ecology. They believed that there were not enough data to support the generalizations that Lindeman was proposing in the paper. In their view, the article was too speculative. The journal’s editor, Thomas Park, turned the article down based on their opinions. Lindeman revised the article, and it was eventually accepted for publication, but not without the strong support of G. Evelyn Hutchinson, who was instrumental in the formation of Lindeman’s ideas. Hutchinson pointed out the importance of Lindeman’s theories in the development of the science of ecology. The paper was published in the fall of 1942, after Lindeman had died of a liver disorder of unknown origin on June 29, 1942. He knew that his work would be published but never knew the significant impact it was to have on the future of ecology.
Lindeman’s theories were based on his five-year study of Cedar Bog Lake, a shallow, weedy body of water. This study was conducted for his doctoral dissertation, awarded by the University of Minnesota. Lindeman and his spouse, Eleanor Lindeman
Lindeman summarized the earlier ideas of community in ecology. He outlined three stages. The first stage included early surveys of lakes and organisms that inhabit them. This view defined lakes as static entities and was concerned with the distribution of species. The second stage in the evolution of community concepts was the dynamic viewpoint that emphasized community succession. Succession refers to changes that ecosystems go through over time. In the case of lakes, they eventually fill in with silt and become terrestrial habitats. The size of the lake and other factors determine the time this change will take. The third stage was the trophic-dynamic view. This view emphasized the role that energy relationships within the community have on the process of succession.
Lindeman created the trophic-dynamic viewpoint to integrate knowledge of food cycle dynamics with principles of community succession. He began his paper with a discussion of community concepts that stressed the functional integration of organic and inorganic cycles of nutritive substances. Lindeman’s use of the term “ecosystem” was significant, since it gave new life to the concept originally developed by Arthur George Tansley
Lindeman expressed the efficiency of production of a trophic (feeding) level by relating its respiration to growth. He also determined the productivity of a level in a food chain as a ratio of the productivity of the previous level. This is now commonly referred to as Lindeman’s ratio
The second law of thermodynamics is often called the law of entropy. Using Lindeman’s 10 percent figure, an imaginary ecosystem with one thousand kilocalories of energy at the primary-producer level would have only one hundred kilocalories available to the herbivores of the second level. There would be ten kilocalories for carnivores at the third level, and only one kilocalorie for secondary carnivores on the fourth level. This means that no matter how much energy is processed by the producers on the first level of an ecosystem, the number of trophic levels that the ecosystem can sustain is limited by the second law of thermodynamics. The usual number of trophic levels is four or five.
The impact of Lindeman’s paper was not evident until the late 1940’s, but his essay is now widely recognized as one of the major turning points in the history of the fields of ecology and limnology (freshwater ecology). The paper provided a sound conceptual model that produced a major shift in the way ecologists approached the study of ecosystems. They began to look at entire ecosystems as the important unit of study. Many ecologists turned away from the previously popular “reductionist” viewpoint of studying only one or a few species and took the holistic view. The importance of the change in mind-set was well illustrated when Eugene P. Odum
Lindeman’s paper was the basis for the future mathematical modeling of ecosystems and the foundation for the field of systems ecology. His major contributions were the emphasis on the significant function that the trophic interactions of an ecosystem have in determining the community patterns in ecological succession, the establishment of a new and solid theoretical foundation for the science of ecology, and the identification of the basic process of energy flow as the factor of primary importance in ecosystem dynamics. The ideas in his paper became the starting point for much of the future research into the flow of energy in animal and plant communities. Many ecological studies rely on the basic theories that Lindeman proposed.
Ecologists now study energetics in even greater detail than Lindeman could. Modern methods enable them to do this because of the availability of much more sophisticated technology. Modern ecologists are able to use radioactive tracers to track the flow of materials and energy through ecosystems. They can introduce isotopes such as radioactive carbon, phosphorus, and other materials into the primary-producer level of a system and follow the path that these materials take as they move through the higher trophic levels and the decomposition process. They can utilize computers to analyze the vast amount of data that can be obtained in this way. They can employ elaborate mathematical techniques and computers to produce mathematical models that more accurately depict ecosystem dynamics. These techniques enable them to get better estimates of productivity and energy flow than Lindeman was able to obtain. Studies of this type have been done in all kinds of habitats, both terrestrial and aquatic. These studies generally continue to validate Lindeman’s basic theories. Although he had only a short career as an ecologist, he stands as a giant in the field.
The holistic approach to research is very important as humankind continues to alter and disrupt ecosystems across the planet. It is valuable to be able to predict what kinds of changes human activities might produce on the ecosystem. Ecologists attempt to model the system in order to explore the interactions occurring throughout the ecosystem. This can lead to predictions about the kind of outcome a particular interference might produce. A decision can then be made about the wisdom of a proposed alteration. The predictions from ecological models are rather imprecise, because natural ecosystems are extremely complicated. There are many relationships between species that are very difficult for the ecologist to identify. Any model will represent a simplification of the actual dynamics of the system, but ecologists hope that improved techniques will lead to better models and thus to better predictions.
The natural extension of Lindeman’s work is the consideration of the energy relationships of the entire biosphere. This is even more complex than the study of a single ecosystem, since the ecosystems themselves interact within the biosphere. Some ecologists and environmentalists are concerned that as humans continue to divert solar energy from natural systems, these systems and perhaps the biosphere itself could be in danger. Solar energy is diverted by converting natural ecosystems to agriculture and by paving over land for buildings and parking lots. These actions eliminate the producer organisms and reduce the amount of energy available to the higher trophic levels.
A reduction in the amount of energy available to a system could reduce the number of trophic levels and thereby simplify the system. This could be a very dangerous change, as more diverse ecosystems seem to be more stable. The effects of these truncated food chains on the biosphere is unknown. This is an issue that modern ecology has only begun to address.
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Cook, Robert Edward. “Raymond Lindeman and the Trophic-Dynamic Concept in Ecology.” Science, October 7, 1977, 22-26. A treatment of the history and importance of Lindeman’s paper. -
Lindeman, Raymond L. “The Developmental History of Cedar Creek Bog, Minnesota.” American Midland Naturalist 25 (1941): 101-112. A paper based on Lindeman’s doctoral dissertation describing Cedar Creek Bog. -
_______. “Seasonal Food-Cycle Dynamics in a Senescent Lake.” American Midland Naturalist 26 (1941): 636-673. A paper based on Lindeman’s doctoral dissertation describing food cycle dynamics in Cedar Creek Bog. -
_______. “The Trophic-Dynamic Aspect of Ecology.” Ecology 23 (1942): 399-418. Lindeman’s classic paper. -
McIntosh, Robert P. The Background of Ecology: Concept and Theory. New York: Cambridge University Press, 1985. A good reference on the historical development and importance of events in ecology. -
Odum, Eugene P. Fundamentals of Ecology. Philadelphia: Saunders, 1953. 5th ed. Belmont, Calif.: Thomson Brooks/Cole, 2005. A classic text in ecology that utilizes the ecosystem approach. -
Woodwell, George M. “The Energy Cycle of the Biosphere.” Scientific American 223 (1970): 64-74. An important paper applying the concepts of energetics to the biosphere.
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