1. Decomposition of Phytoplankton in Seawater. Part I: Kinetic Analysis of the Effect of Organic Matter Concentration
- Author
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Fujii, Minoru, Murashige, Shinichiro, Ohnishi, Yuka, Yuzawa, Atushi, Miyasaka, Hitoshi, Suzuki, Yoshimi, and Komiyama, Hiroshi
- Subjects
Marine phytoplankton -- Properties ,Biodegradation -- Research ,Chemistry, Physical organic -- Research ,Science and technology - Abstract
Byline: Minoru Fujii (1), Shinichiro Murashige (1), Yuka Ohnishi (2), Atushi Yuzawa (3), Hitoshi Miyasaka (4), Yoshimi Suzuki (2), Hiroshi Komiyama (1) Keywords: Concentration; decomposition; phytoplankton; particulate organic matter; kinetics; cultivation Abstract: Decomposition experiments were conducted on cultured phytoplankton (Skeletonema costatum) in seawater containing decomposer and consumer of size less than 500 Aum. We determined the decomposition rates of bulk particulate organic matter (POM), the ratio of labile to semi-refractory fractions in the POM, and the POM carbon/ nitrogen (C/N) ratio during decomposition. To identify the kinetic mechanisms involved in the reactions of different order (e.g., first- and second-order), we studied the sensitivity of reaction rates to the initial concentration of POM, ranging from 2.4 to 71 mg-C L.sup.-1. The results showed that decomposition consists of two first-order reactions: decomposition of labile and of semi-refractory particulate organic carbon (POC). The decomposition rate constants found for labile (0.13 day.sup.-1 at 20degC), and semi-refractory POC (0.008 day.sup.-1 at 20degC), and the carbon weight ratio of semi-refractory POC (13% at 20degC), were insensitive to the initial organic matter concentration. The time-dependence of the C/N ratio was also independent of this initial concentration. The decomposition rate constants and the content of semi-refractory POC did not change, regardless of the absence or presence of 25--500 Aum organisms in natural seawater. Author Affiliation: (1) Department of Chemical System Engineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan (2) Department of Biology and Geosciences, Faculty of Science, Shizuoka University, Shizuoka, 422-8529, Japan (3) Japan NUS Co., Ltd., LOOP-X BLDG., 8F 9-15 Kaigan 3-chome, Minato-ku, Tokyo, 108-0022, Japan (4) Technical Research Center, Kansai Electric Power Co., Inc., Amagasaki, Hyogo, 661-0974, Japan Article History: Registration Date: 12/10/2004 more...
- Published
- 2002