Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments

It is generally assumed that the larger the bottle volume, the longer the duration of phytoplankton microcosm experiments. We hypothesize that volume and duration are independent, as volume does not regulate the extension of the exponential growth phase. We conducted two microcosm experiments using...

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Main Authors: Rita B. Domingues, Benjamin A. Mosley, Patrícia Nogueira, Inês B. Maia, Ana B. Barbosa
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Water
Subjects:
Online Access:https://www.mdpi.com/2073-4441/15/2/372
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author Rita B. Domingues
Benjamin A. Mosley
Patrícia Nogueira
Inês B. Maia
Ana B. Barbosa
author_facet Rita B. Domingues
Benjamin A. Mosley
Patrícia Nogueira
Inês B. Maia
Ana B. Barbosa
author_sort Rita B. Domingues
collection DOAJ
description It is generally assumed that the larger the bottle volume, the longer the duration of phytoplankton microcosm experiments. We hypothesize that volume and duration are independent, as volume does not regulate the extension of the exponential growth phase. We conducted two microcosm experiments using 1, 2, and 8 L bottles, inoculated with phytoplankton collected in the Ria Formosa lagoon (SE Portugal) and incubated for 1, 2, 4, and 8 days. Phytoplankton net growth rates were estimated using chlorophyll <i>a</i> concentration and cell abundance, determined with epifluorescence and inverted microscopy. Results show that the experimental duration significantly affected net growth rates, independently of volume, with decreasing net growth rates with time. Regarding volume, we found significant, but weak, differences in net growth rates, and significant two-way interactions only for the larger-sized cells. No significant differences in net growth rates across the different volumes were detected for the smaller, most abundant taxa and for the whole assemblage. We conclude that duration, not volume, is the main factor to consider in microcosm experiments, and it should allow the measurement of responses during the exponential growth phase, which can be detected through daily sampling throughout the duration of the experiment.
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spelling doaj.art-bbd3c1e01e0e4a4e8abf65d80bb5db2c2023-12-01T01:19:03ZengMDPI AGWater2073-44412023-01-0115237210.3390/w15020372Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm ExperimentsRita B. Domingues0Benjamin A. Mosley1Patrícia Nogueira2Inês B. Maia3Ana B. Barbosa4Centre for Marine and Environmental Research, University of Algarve, 8005-139 Faro, PortugalCentre for Marine and Environmental Research, University of Algarve, 8005-139 Faro, PortugalCentre for Marine and Environmental Research, University of Algarve, 8005-139 Faro, PortugalCentre for Marine and Environmental Research, University of Algarve, 8005-139 Faro, PortugalCentre for Marine and Environmental Research, University of Algarve, 8005-139 Faro, PortugalIt is generally assumed that the larger the bottle volume, the longer the duration of phytoplankton microcosm experiments. We hypothesize that volume and duration are independent, as volume does not regulate the extension of the exponential growth phase. We conducted two microcosm experiments using 1, 2, and 8 L bottles, inoculated with phytoplankton collected in the Ria Formosa lagoon (SE Portugal) and incubated for 1, 2, 4, and 8 days. Phytoplankton net growth rates were estimated using chlorophyll <i>a</i> concentration and cell abundance, determined with epifluorescence and inverted microscopy. Results show that the experimental duration significantly affected net growth rates, independently of volume, with decreasing net growth rates with time. Regarding volume, we found significant, but weak, differences in net growth rates, and significant two-way interactions only for the larger-sized cells. No significant differences in net growth rates across the different volumes were detected for the smaller, most abundant taxa and for the whole assemblage. We conclude that duration, not volume, is the main factor to consider in microcosm experiments, and it should allow the measurement of responses during the exponential growth phase, which can be detected through daily sampling throughout the duration of the experiment.https://www.mdpi.com/2073-4441/15/2/372microcosmsexperimental designbottle volumeincubation periodphytoplanktonexperimental ecology
spellingShingle Rita B. Domingues
Benjamin A. Mosley
Patrícia Nogueira
Inês B. Maia
Ana B. Barbosa
Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
Water
microcosms
experimental design
bottle volume
incubation period
phytoplankton
experimental ecology
title Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
title_full Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
title_fullStr Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
title_full_unstemmed Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
title_short Duration, but Not Bottle Volume, Affects Phytoplankton Community Structure and Growth Rates in Microcosm Experiments
title_sort duration but not bottle volume affects phytoplankton community structure and growth rates in microcosm experiments
topic microcosms
experimental design
bottle volume
incubation period
phytoplankton
experimental ecology
url https://www.mdpi.com/2073-4441/15/2/372
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