Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration

Microbial respiration is a key metabolic process in the ocean carbon cycle. However, so far there is not a “gold standard” method to estimate respiration in the sea. Direct oxygen consumption “in vitro” methods rely on long incubations (24h) inside glass bottles, which may enhance changes in the enc...

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Detalles Bibliográficos
Autor: Baños Cerón, María Isabel
Tipo de recurso: tesis de maestría
Fecha de publicación:2012
País:España
Repositorio:accedaCRIS portal de investigación de la Universidad de las Palmas de Gran Canaria
OAI Identifier:oai:accedacris.ulpgc.es:10553/11392
Acceso en línea:http://hdl.handle.net/10553/11392
Access Level:acceso abierto
Palabra clave:251001 Oceanografía biológica
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spelling Bottle effects, toxicity and cell viability during incubation experiments to asses community respirationBaños Cerón, María Isabel251001 Oceanografía biológicaMicrobial respiration is a key metabolic process in the ocean carbon cycle. However, so far there is not a “gold standard” method to estimate respiration in the sea. Direct oxygen consumption “in vitro” methods rely on long incubations (24h) inside glass bottles, which may enhance changes in the enclosed natural populations. Recently, an enzymatic in vivo ETS assay has been proposed as an alternative to estimate “actual” respiration in shorter incubation periods (<6 h). Here we have investigated two main factors that we consider may affect incubations in both the “in vitro” oxygen consumption experiments and the “in vivo” ETS assays: (i) The effect of enclosing natural population in bottles of different volume (125, 250 and 1000 mL) during 24 h, and (ii) The potential toxic effect of the INT (which is reduced to INT-F during the ETS assay) over natural populations, during the incubation period. We tested the “bottle effect” in the whole planktonic community (C) as well as in the filtered (through 1.2 μm filter) microbial community (F), along three experiments. Our results show variable responses of natural communities during the incubation inside bottles, but without any significant difference between the bottles’ volume used. The general pattern of these changes (both in the total and fractionated communities) is a moderate decrease in phytoplankton populations and a sharp increase in bacterial assemblages (favouring the growth of HNA cells), which would presumably affect the final metabolic rates. On the other hand, we tested the toxicity of the INT during a typical in vivo ETS assay (6 h incubation, 0.2 mM INT). The results of this single experiment show that, after the INT addition, there is (i) a complete loss of Prochlorococcus cells, and a moderate loss of Synechococcus and picoeukaryotes, (ii) an increase in HNA bacteria (presumably by the uptake of newly organic substrates from phytoplankton death) but a decrease in LNA bacteria, and (iii) a decline in bacterial viability, which is produced in the first 0.5 h, superimposed to the growth of HNA bacteria. In summary, our results highlight the importance of monitoring the evolution of microbial communities along incubations (both in the “in vitro” oxygen consumption experiments and “in vivo” ETS assays) and warn of some important methodological constraints that may drastically influence the actual respiratory rates.Máster en Oceanografía ; 2012Arístegui Ruiz, JavierMontero del Pino, María F.IU de Oceanografía y Cambio GlobalBiologíaFacultad de Ciencias del MarBU-BASMáster Universitario en Oceanografía20142018201420182012info:eu-repo/semantics/masterThesisMasterThesisapplication/pdfhttp://hdl.handle.net/10553/11392reponame:accedaCRIS portal de investigación de la Universidad de las Palmas de Gran Canariainstname:Inglésby-nc-ndinfo:eu-repo/semantics/openAccessoai:accedacris.ulpgc.es:10553/113922025-08-04T10:01:22Z
dc.title.none.fl_str_mv Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
title Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
spellingShingle Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
Baños Cerón, María Isabel
251001 Oceanografía biológica
title_short Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
title_full Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
title_fullStr Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
title_full_unstemmed Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
title_sort Bottle effects, toxicity and cell viability during incubation experiments to asses community respiration
dc.creator.none.fl_str_mv Baños Cerón, María Isabel
author Baños Cerón, María Isabel
author_facet Baños Cerón, María Isabel
author_role author
dc.contributor.none.fl_str_mv Arístegui Ruiz, Javier
Montero del Pino, María F.
IU de Oceanografía y Cambio Global
Biología
Facultad de Ciencias del Mar
BU-BAS
Máster Universitario en Oceanografía
dc.subject.none.fl_str_mv 251001 Oceanografía biológica
topic 251001 Oceanografía biológica
description Microbial respiration is a key metabolic process in the ocean carbon cycle. However, so far there is not a “gold standard” method to estimate respiration in the sea. Direct oxygen consumption “in vitro” methods rely on long incubations (24h) inside glass bottles, which may enhance changes in the enclosed natural populations. Recently, an enzymatic in vivo ETS assay has been proposed as an alternative to estimate “actual” respiration in shorter incubation periods (<6 h). Here we have investigated two main factors that we consider may affect incubations in both the “in vitro” oxygen consumption experiments and the “in vivo” ETS assays: (i) The effect of enclosing natural population in bottles of different volume (125, 250 and 1000 mL) during 24 h, and (ii) The potential toxic effect of the INT (which is reduced to INT-F during the ETS assay) over natural populations, during the incubation period. We tested the “bottle effect” in the whole planktonic community (C) as well as in the filtered (through 1.2 μm filter) microbial community (F), along three experiments. Our results show variable responses of natural communities during the incubation inside bottles, but without any significant difference between the bottles’ volume used. The general pattern of these changes (both in the total and fractionated communities) is a moderate decrease in phytoplankton populations and a sharp increase in bacterial assemblages (favouring the growth of HNA cells), which would presumably affect the final metabolic rates. On the other hand, we tested the toxicity of the INT during a typical in vivo ETS assay (6 h incubation, 0.2 mM INT). The results of this single experiment show that, after the INT addition, there is (i) a complete loss of Prochlorococcus cells, and a moderate loss of Synechococcus and picoeukaryotes, (ii) an increase in HNA bacteria (presumably by the uptake of newly organic substrates from phytoplankton death) but a decrease in LNA bacteria, and (iii) a decline in bacterial viability, which is produced in the first 0.5 h, superimposed to the growth of HNA bacteria. In summary, our results highlight the importance of monitoring the evolution of microbial communities along incubations (both in the “in vitro” oxygen consumption experiments and “in vivo” ETS assays) and warn of some important methodological constraints that may drastically influence the actual respiratory rates.
publishDate 2012
dc.date.none.fl_str_mv 2012
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