Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent

Phytoplankton cell size influences particle sinking rate, food web interactions and biogeographical distributions. We present a model in which the uptake, storage and assimilation of nitrogen and carbon are explicitly resolved in different-sized phytoplankton cells. In the model, metabolism...

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Main Authors: D. Talmy, J. Blackford, N. J. Hardman-Mountford, L. Polimene, M. J. Follows, R. J. Geider
Format: Article
Language:English
Published: Copernicus Publications 2014-09-01
Series:Biogeosciences
Online Access:http://www.biogeosciences.net/11/4881/2014/bg-11-4881-2014.pdf
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spelling doaj-865c3157c00440808e60509f8f8f6b5f2020-11-24T22:25:58ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-09-0111174881489510.5194/bg-11-4881-2014Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittentD. Talmy0J. Blackford1N. J. Hardman-Mountford2L. Polimene3M. J. Follows4R. J. Geider5School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UKPlymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, Devon, UKCommonwealth Scientific and Industrial Research Organization, Marine and Atmospheric Research, Centre for Environment and Life Sciences, Floreat, AustraliaPlymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, Devon, UKDepartment of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USASchool of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UKPhytoplankton cell size influences particle sinking rate, food web interactions and biogeographical distributions. We present a model in which the uptake, storage and assimilation of nitrogen and carbon are explicitly resolved in different-sized phytoplankton cells. In the model, metabolism and cellular C : N ratio are influenced by the accumulation of carbon polymers such as carbohydrate and lipid, which is greatest when cells are nutrient starved, or exposed to high light. Allometric relations and empirical data sets are used to constrain the range of possible C : N, and indicate that larger cells can accumulate significantly more carbon storage compounds than smaller cells. When forced with extended periods of darkness combined with brief exposure to saturating irradiance, the model predicts organisms large enough to accumulate significant carbon reserves may on average synthesize protein and other functional apparatus up to five times faster than smaller organisms. The advantage of storage in terms of average daily protein synthesis rate is greatest when modeled organisms were previously nutrient starved, and carbon storage reservoirs saturated. Small organisms may therefore be at a disadvantage in terms of average daily growth rate in environments that involve prolonged periods of darkness and intermittent nutrient limitation. We suggest this mechanism is a significant constraint on phytoplankton C : N variability and cell size distribution in different oceanic regimes.http://www.biogeosciences.net/11/4881/2014/bg-11-4881-2014.pdf
collection DOAJ
language English
format Article
sources DOAJ
author D. Talmy
J. Blackford
N. J. Hardman-Mountford
L. Polimene
M. J. Follows
R. J. Geider
spellingShingle D. Talmy
J. Blackford
N. J. Hardman-Mountford
L. Polimene
M. J. Follows
R. J. Geider
Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
Biogeosciences
author_facet D. Talmy
J. Blackford
N. J. Hardman-Mountford
L. Polimene
M. J. Follows
R. J. Geider
author_sort D. Talmy
title Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
title_short Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
title_full Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
title_fullStr Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
title_full_unstemmed Flexible C : N ratio enhances metabolism of large phytoplankton when resource supply is intermittent
title_sort flexible c : n ratio enhances metabolism of large phytoplankton when resource supply is intermittent
publisher Copernicus Publications
series Biogeosciences
issn 1726-4170
1726-4189
publishDate 2014-09-01
description Phytoplankton cell size influences particle sinking rate, food web interactions and biogeographical distributions. We present a model in which the uptake, storage and assimilation of nitrogen and carbon are explicitly resolved in different-sized phytoplankton cells. In the model, metabolism and cellular C : N ratio are influenced by the accumulation of carbon polymers such as carbohydrate and lipid, which is greatest when cells are nutrient starved, or exposed to high light. Allometric relations and empirical data sets are used to constrain the range of possible C : N, and indicate that larger cells can accumulate significantly more carbon storage compounds than smaller cells. When forced with extended periods of darkness combined with brief exposure to saturating irradiance, the model predicts organisms large enough to accumulate significant carbon reserves may on average synthesize protein and other functional apparatus up to five times faster than smaller organisms. The advantage of storage in terms of average daily protein synthesis rate is greatest when modeled organisms were previously nutrient starved, and carbon storage reservoirs saturated. Small organisms may therefore be at a disadvantage in terms of average daily growth rate in environments that involve prolonged periods of darkness and intermittent nutrient limitation. We suggest this mechanism is a significant constraint on phytoplankton C : N variability and cell size distribution in different oceanic regimes.
url http://www.biogeosciences.net/11/4881/2014/bg-11-4881-2014.pdf
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