Data/hora: 01/06/2024 08:18:05

Provedor de dados: 	13	
País: 	Ukraine	
Título: 	Microcalorimetry of the smallest plankton fraction: in search for the sources of heat dissipation

Микрокалориметрия мельчайшей фракции планктона: поиск источников теплопродукции

Мікрокалориметрія дрібної фракції планктону: пошук джерел теплопродукції	
Autores: 	Mukhanov, V. S.; Kemp, R. B.	
Data: 	2007-08-27	
Ano: 	2005	
Palavras-chave: 	Microcalorimetry; Heat production; Ultramicrobacteria; Virioplankton; Bacterioplankton; Extracellular enzyme activity; Микрокалориметрия; Теплопродукция; Ультрамикробактерии; Вириопланктон; Бактериопланктон; Внеклеточная ферментативная активность.	
Resumo: 	Heat production by the plankton pico (0.2 to 2 μm) and femto (&lt;0.2 μm) fractions was measured in the dark using a microcalorimetric method. It was surprisingly found that the femtofraction (FF) produced more heat per seawater volume (48 ± 24  (95% CI) μW l-1) than the picofraction (25 ± 14 μW l-1). Consequently, we tested two hypotheses which could explain the phenomenon through a differentiation between the potential sources of heat in FF: (i) metabolism of ultramicrobacteria, the only living component in the fraction besides the non-metabolizing virioplankton which are unable to produce heat; (ii) extracellular chemical processes in aquatic environments. Results of microcalorimetry and respirometry combined with the use of antimicrobial agents (ciprofloxacin, glutaraldehide, sodium azide), and microscopical examination (counts and sizing of bacteria in the measuring ampoules) showed that both sources contributed to the overall heat flow by FF but the non-living component was responsible for the bulk of it. Hydrolysis of high molecular weight organic substances dissolved in seawater, associated with bacterial extracellular enzyme activity, is considered the most probable source of the heat. If so, microcalorimetry has great prospective in aquatic microbial ecology and biochemistry as a powerful unspecific analytical method.	
Tipo: 	Journal Contribution	
Idioma: 	Inglês	
Identificador: 	Morskyji ehkologichnyji zhurnal/Marine ecological journal/Morskoj ehkologicheskij zhurnal, 4(Special issue 1). p. 84-98

1684-1557

http://repository.ibss.org.ua/dspace/handle/99011/234	
Formato: 	26803 bytes

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