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THE LIMNOLOGY OF CANYON FERRY RESERVOIR IV. THE ESTIMATION OF PRIMARY PRODUCTION FROM PHYSICAL LIMNOLOGICAL DATA 1
Author(s) -
Wright John C.
Publication year - 1961
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1961.6.3.0330
Subject(s) - photic zone , hypolimnion , epilimnion , thermocline , seston , oxygen , raceway , atmospheric sciences , hydrology (agriculture) , chemistry , environmental science , thermodynamics , geology , phytoplankton , oceanography , physics , eutrophication , geotechnical engineering , organic chemistry , finite element method , nutrient
Biological rates of oxygen production and consumption were computed by adding the rates of turbulent transport of oxygen to the observed rates of change in concentration at successive depths. This involved using coefficients of vertical eddy diffusivity which were assumed to be equivalent to coefficients of vertical eddy conductivity, computed on the basis of a heat transport equation utilizing Birgean heat budgets. An attempt was made to assess the validity of the coefficients as follows. In the clinolimnion, the average values of the coefficients were similar when computed either on the basis of temperature change with depth and time or on the basis of the heat transport equation. A satisfactory correlation was obtained between the coefficients and a function of shearing stress (velocity gradient) and resistance to mixing (stability). The coefficients decreased with increasing depth in the epilimnion, became minimal and constant in the metalimnion and increased in the hypolimnion. Oxygen consumption exceeded oxygen production below 5.5 m and was maximal just below the euphotic zone (9–12 m). Oxygen consumption was minimal in the metalimnion and increased in the hypolimnion. An oxygen concentration maximum was correlated with the metalimnetic oxygen consumption minimum. Euphotic zone oxygen production equivalent to dysphotic zone oxygen consumption amounted to 1.01 g O 2 /m 2 /day. Euphotic zone respiration would have been 1.21 g O 2 /m 2 /day if it proceeded at the same rate as in the 9‐ to 12‐m stratum. On the basis of the ratios, oxygen consumption/chlorophyll and oxygen consumption/seston euphotic zone respiration amounted to 1.44 g O 2 /m 2 /day and 2.01 g O 2 /m 2 /day respectively. Gross production values then would range between 2.22 g O 2 /m 2 / day and 3.02 g O 2 /m 2 /day. The latter value was extremely close to black and clear bottle estimates of 3.00 g O 2 /m 2 /day.