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Adding artificial feedback to a simple aquatic ecosystem: the cybernetic nature of ecosystems revisited
Author(s) -
Petersen John E.
Publication year - 2001
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1034/j.1600-0706.2001.940315.x
Subject(s) - cybernetics , ecosystem , productivity , aquatic ecosystem , computer science , ecology , control theory (sociology) , environmental science , biochemical engineering , control (management) , biological system , artificial intelligence , biology , engineering , economics , macroeconomics
A cybernetic system can be defined as one controlled by feedback, that is, a system in which input is partially determined by output. I explored the cybernetic properties of a simple planktonic ecosystem by introducing an artificial feedback loop; light energy delivered to the system was linked to the ecosystem's productivity and respiration. Specifically, I programmed a computer to turn lights on and off when dissolved oxygen reached low and high setpoints, respectively. Three treatments were applied that differed in light intensity and in range between high and low setpoints. Experiments were repeated under high and low nutrient conditions. The added feedback did not substantially alter responses to limiting factors from those expected under fixed duration lighting. However, several novel features were observed, including poor coupling between productivity and respiration, similar patterns in energy demand among treatments, and oscillations in primary productivity. These observations can be viewed as support for a holistic, cybernetic view of ecological systems. This view complements the dominant mechanistic‐reductionist perspective on causality in ecosystems. The experimental addition of new feedback is apparently a useful means of investigating the self‐organizational properties of ecosystems and may also improve our understanding of the consequences of anthropogenically induced feedback in natural and managed systems.