Historical Survey of Primary Productivity Research

Abstract

From a recent paper on the history of the discovery of photosynthesis (Rabinovitch, 1971), it appears that many biologists equate photosynthesis with productivity and identify the raw materials of photosynthesis (water, carbon dioxide, and sunlight energy) as the direct controls of productivity. Photosynthesis and primary productivity are not so simply identical. Indeed, primary productivity—the actual energy bound into organic matter—is the product of photosynthesis. Yet primary productivity requires more than photosynthesis alone. The uptake and incorporation of inorganic nutrients into the diverse organic compounds of protoplasm are essential to the photosynthesizing organism. Temperatures govern annual productivity in various ways that do not result from temperature dependence of the photosynthetic process. On land, productivity is strongly affected by the availability of water, not primarily for use in the photosynthetic process itself, but to replace the water lost through the stomata that are open to allow carbon dioxide uptake.