Carbon flow into the end-products of photosynthesis in short and long incubations of a natural phytoplankton population

1982 ◽  
Vol 72 (2) ◽  
pp. 175-182 ◽  
Author(s):  
W. K. W. Li ◽  
W. G. Harrison
Keyword(s):  
Carbon Flow ◽  
Phytoplankton Population ◽  
End Products ◽  
Natural Phytoplankton

Fatty acid composition in photosynthetic products of natural phytoplankton population in Lake Biwa, Japan

1992 ◽  
Vol 14 (8) ◽  
pp. 1055-1065 ◽  
Author(s):  
Takeo Hama ◽  
Katsuji Matsunaga ◽  
Nobuhiko Handa ◽  
Mikio Takahashi
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Lake Biwa ◽  
Phytoplankton Population ◽  
Photosynthetic Products ◽  
Natural Phytoplankton

scholarly journals Cellulose Catabolism by Clostridium cellulolyticum Growing in Batch Culture on Defined Medium

2000 ◽  
Vol 66 (6) ◽  
pp. 2461-2470 ◽  
Author(s):  
Mickaël Desvaux ◽  
Emmanuel Guedon ◽  
Henri Petitdemange
Keyword(s):  
Batch Culture ◽  
Cellulose Degradation ◽  
Growth Arrest ◽  
Dry Weight ◽  
Defined Medium ◽  
Carbon Flow ◽  
Natural Ecosystem ◽  
Clostridium Cellulolyticum ◽  
End Products ◽  
Cellulose Concentration

ABSTRACT A reinvestigation of cellulose degradation by Clostridium cellulolyticum in a bioreactor with pH control of the batch culture and using a defined medium was performed. Depending on cellulose concentration, the carbon flow distribution was affected, showing the high flexibility of the metabolism. With less than 6.7 g of cellulose liter−1, acetate, ethanol, H2, and CO2 were the main end products of the fermentation and cellulose degradation reached more than 85% in 5 days. The electron flow from the glycolysis was balanced by the production of H2 and ethanol, the latter increasing with increasing initial cellulose concentration. From 6.7 to 29.1 g of cellulose liter−1, the percentage of cellulose degradation declined; most of the cellulase activity remained on the cellulose fibers, the maximum cell density leveled off, and the carbon flow was reoriented from ethanol to acetate. In addition to that of previously indicated end products, lactate production rose, and, surprisingly enough, pyruvate overflow occurred. Concomitantly the molar growth yield and the energetic yield of the biomass decreased. Growth arrest may be linked to sufficiently high carbon flow, leading to the accumulation of an intracellular inhibitory compound(s), as observed on cellobiose (E. Guedon, M. Desvaux, S. Payot, and H. Petitdemange, Microbiology 145:1831–1838, 1999). These results indicated that bacterial metabolism exhibited on cellobiose was distorted compared to that exhibited on a substrate more closely related to the natural ecosystem of C. cellulolyticum. To overcome growth arrest and to improve degradation at high cellulose concentrations (29.1 g liter−1), a reinoculation mode was evaluated. This procedure resulted in an increase in the maximum dry weight of cells (2,175 mg liter−1), cellulose solubilization (95%), and end product concentrations compared to a classical batch fermentation with a final dry weight of cells of 580 mg liter−1 and 45% cellulose degradation within 18 days.

Grazing dynamics of Euphausia spinifera in the region of the Subtropical Convergence and the Agulhas Front

2001 ◽  
Vol 58 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Renzo Perissinotto ◽  
Patrick Mayzaud ◽  
Jean-Philippe Labat ◽  
Suzanne Razouls
Keyword(s):  
Antarctic Krill ◽  
Euphausia Superba ◽  
Size Selectivity ◽  
Important Species ◽  
Chl A ◽  
End Products ◽  
Gut Evacuation ◽  
Area North ◽  
Gut Pigment ◽  
Natural Phytoplankton

The feeding ecophysiology of the subtropical euphausiid Euphausia spinifera was investigated in the Indian sector of the Southern Ocean during January–February 1999. Gut pigment levels varied from 1.7 to 40.6 ng chlorophyll a (Chl a) equiv.·individual–1 in adults and from 0.3 to 9.3 ng Chl a equiv.·individual–1 in juveniles. Highest levels were observed at the Subtropical Convergence (Chl a concentrations 0.4–0.6 µg·L–1) and minima in the area north of the Agulhas Front (Chl a concentrations 0.2–0.3 µg·L–1). Gut evacuation rates ranged between 0.59 and 0.96·h–1. Gut pigment destruction levels were among the highest ever recorded in euphausiids, with 94.2–98.5% of total pigments ingested converted to nonfluorescing end products. Size-selectivity experiments with natural phytoplankton showed that E. spinifera ingests mainly cells in the 0.7- to 20-µm range. The grazing dynamics of this important species are compared with those of subantarctic (Euphausia vallentini) and Antarctic krill (Euphausia superba). Individual ingestion rates, estimated from the autotrophic component of its diet (2.78–4.46 µg Chl a equiv.·individual–1·day–1), were just sufficient to account for respiratory requirements. While E. spinifera is clearly able to ingest large amounts of heterotrophic prey, it is not known to what extent these contribute to its total energy budget.

Day-night changes in production of carbohydrate and protein by natural phytoplankton population from Lake Biwa, Japan

1988 ◽  
Vol 10 (5) ◽  
pp. 941-955 ◽  
Author(s):  
Takeo Hama ◽  
Katsuji Matsunaga ◽  
Nobuhiko Handa ◽  
Mikio Takahashi
Keyword(s):  
Lake Biwa ◽  
Phytoplankton Population ◽  
Natural Phytoplankton

scholarly journals Intraseasonal predictability of natural phytoplankton population dynamics

2021 ◽  
Author(s):  
Vitul Agarwal ◽  
Chase C. James ◽  
Claire E. Widdicombe ◽  
Andrew D. Barton
Keyword(s):  
Population Dynamics ◽  
Phytoplankton Population ◽  
Natural Phytoplankton
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