Productivity of Florida Springs: First annual (3rd semi-annual) report to Biology Branch, Office of Naval Research progress from January 1 to December 31, 1953

摘要

By means of new methods it has been possible to measure the overall community metabolism as well as the standing state community in Silver Springs. Photosynthetic rates have been determined by downstream gradientudmethods, transplantation growth plots, and bell jars diurnally and annually.udRespiration rates have been estimated with bell jars. The downstream lossesudof particulate, and dissolved organic matter have been found to balance, the excess of photosynthesis over respiration. The community has thus been demonstrated to be in a constant temperature, steady state, somewhat comparable to a climax on land. Nitrate, phosphate, and major chemical constituents are essentially constant.ud There is an approximate constancy of standing udcrop of organisms although the production rates in summer are three timesudthose in the winter. Some evidence suggests that there, are photoperiodic changes in reproduction rates in spite of constant temperature. Rates of protein syntehsis estimated from nitrate uptake downstream agree (1) with photosynthetic quotients obtained from carbon dioxide and oxygen uptake downstream and (2) with the nitrogen content of the community. The overall annual production of 50,000 lbs/acre is the greatest productivity we know of on land or sea. Such high figures seem reasonable with the flow of high nutrient, warm water and high light intensity over a dense periphyton community. Theoretical concepts of steady state thermodynamics have been applied to show that self maintaining open systems tend to adjust to high power and low efficiency output. The 3% photosynthetic efficiency observed in Silver Springs is in agreement with this principle. Pyramids of weight and pyramids of number have been determined including bacteria. These pyramids are similar to some in the literature. The contribution of an acre of a fertile stream annually is readily inferred from data obtained on downstream increase of bacteria, chlorophyll, and organic matter.ududIn other springs, Mr. Sloan has related stability of insect populations to chlorinity and to gradients of stability of environmental factors. Dr. L.S. Whitford during the summer made an ecological and taxonomic study of the distribution of algae in 26 contrasting springs. From this lists and from analytical data on the chemostatic water in these springs one can infer culture conditions necessary for many species.udud(27 pages)