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Seasonal changes in respiratory enzyme activity and productivity in Lake Washington microplankton. Limnol. Oceanogr. 23: 104-l 11 (1978)
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BibTeX
@MISC{Devol78seasonalchanges,
author = {Allan H. Devol and T. T. Packard},
title = {Seasonal changes in respiratory enzyme activity and productivity in Lake Washington microplankton. Limnol. Oceanogr. 23: 104-l 11},
year = {1978}
}
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Abstract
The seasonal cycle of respiratory electron transport system (ETS) activity, 14C uptake, chlorophyll, temperature, and nutrient concentration in the euphotic zone of Lake Washington during 1974 shows minimum ETS activity (4.2 mg 0,,m-2h-*), “C uptake (84 mg C mv2d-‘), and chlorophyll (10.1 mg mm2) occurred in the first few months of the year and coincided with minimum temperature (-6.2”C) and maximum nutrient concentrations (P043- = 250 mg rnm2, N03- = 3.5 g m-“). Maximum ETS activity (109.8 mg Oeam-2h-1), 14C uptake (2,126 mg C me2d-‘) and hl c orophyll(l21.7 mg m-“) were observed during the spring bloom. Values were intermediate during the fall period of thermal stratification and nutrient depletion. Respira-tion rates were calculated from ETS activities and used to calculate production:rcspiration ratios (P:R). The P:R ratios were low in late summer and fall and high in winter. The percent-age of primary production oxidized during a 12-h dark period varied from> 100 % to 7%: high percentages in summer, low in late winter. Dark respiration should be considered in any study of the fate of photosyntheti-cally fixed carbon. Ryther (1954, 1956) showed that 10 to 40 % of the 14C-carbon recently incorporated by marine algae could be lost in a 4-h dark period and indicated the importance of the photo-synthesis:respiration ratio (P:R) in evalu-ating productivity data. Steele (1965, p. 392) proposed that the P:R ratio may be “the main single measure we can obtain of the physiological state of the [phyto-plankton] population. ” Furthermore, Epp-ley and Sharp (1975) suggested dark respi-ration may significantly reduce the amount of primary production, as calcu-lated from short term (4 to 6 h) 14C in-cubations, that is available to grazing or-ganisms. Dark respiration could be calculated from production if the P:R ratio were constant or predictable, This would be
Keyphrases
seasonal change respiratory enzyme activity lake washington microplankton dark respiration primary production late winter late summer minimum temperature euphotic zone main single measure lake washington maximum ets activity respira-tion rate respiratory electron transport system seasonal cycle nutrient concentration rcspiration ratio short term 12-h dark period ets activity mg rnm2 mg mm2 4-h dark period mg mv2d respiration ratio maximum nutrient concentration spring bloom fall period mg me2d phyto-plankton population high percentage thermal stratification evalu-ating productivity data physiological state marine algae dark respi-ration show minimum ets activity nutrient depletion photosyntheti-cally fixed carbon mg oeam-2h-1 first month
