Resumo
Some aspects of the procedures to measure dissolved organic matter (DOM) released by phytoplankton account for important sources of errors. These aspects include: cell damage upon filtration of samples, residual inorganic 14C in the filtrates, NaH14CO3 ampoule contaminations and the low radiation activity proper to the released samples. Some experiments on these procedural problems were carried out and their effects on the released DOM were evaluated. A procedure to use control samples to avoid errors in the technique of DOM analysis by the liquid cintillation counter is described. Experiments on the validity of stocking preserved filtrates of natural plankton populations and algal cultures were also carried out for long periods prior to the radioactivity measurements.
ARTIGOS
Alguns aspectos metodológicos da medida da excreção de matéria orgânica pelo fitoplâncton por espectrometria de cintilação líquida* * Trabalho realizado no Instituto Oceanográfico da U.S.P. com suporte financeiro da FINEP.
Some aspects of liquid scintillation spectrometric procedures to measure dissolved organic matter released by phytoplankton
Armando A. H. VieiraI; Elizabeth Aidar-AragãoII
IDepartamento de Ciências Biologicas, Universidade Federal de São Carlos
IIInstituto Oceanográfico da Universidade de São Paulo
SYNOPSIS
Some aspects of the procedures to measure dissolved organic matter (DOM) released by phytoplankton account for important sources of errors. These aspects include: cell damage upon filtration of samples, residual inorganic 14C in the filtrates, NaH14CO3 ampoule contaminations and the low radiation activity proper to the released samples. Some experiments on these procedural problems were carried out and their effects on the released DOM were evaluated. A procedure to use control samples to avoid errors in the technique of DOM analysis by the liquid cintillation counter is described. Experiments on the validity of stocking preserved filtrates of natural plankton populations and algal cultures were also carried out for long periods prior to the radioactivity measurements.
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Agradecimentos
Os autores agradecem ao MSc Carlos Henrique Mesquita do Instituto de Pesquisas Energéticas e Nucleares (IPEN) pelas valiosas criticas e sugestões recebidas.
(Manuscrito recebido em 23/fev./1981; aceito em 25/fev./1982)
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Datas de Publicação
-
Publicação nesta coleção
04 Jun 2012 -
Data do Fascículo
1982
Histórico
-
Aceito
25 Fev 1982 -
Recebido
23 Fev 1981