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The theory of secondary production calculations for continuously reproducing populations
Author(s) -
Kimmerer W. J.
Publication year - 1987
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.1987.32.1.0001
Subject(s) - production (economics) , zooplankton , simple (philosophy) , statistics , interval (graph theory) , mathematics , benthic zone , econometrics , computer science , mathematical optimization , biology , ecology , combinatorics , economics , philosophy , macroeconomics , epistemology
Definitions and mathematical expressions currently used to calculate secondary production are based on the observation of development in cohorts. Most populations of marine zooplankton and many benthic populations do not meet the strict conditions necessary for measurement of growth and mortality in cohorts, and application of the mathematics used in cohort methods to such populations can lead to errors. A better approach is to assume approximate steady state and to determine integrated production (IP) over a time period from observations of the instantaneous production rate, PR. The determination of IP consists of two steps: measurement of PR, usually by a direct method, and integration. The value of IP determined from PR over a given time interval depends on assumptions about the trajectory of PR between samples. I use several simple models to demonstrate that mortality need not be measured and that IP can be determined from sample data on PR. The best estimate of IP is a simple sum of PR values multiplied by appropriate time intervals.