Body size, light intensity and nutrient supply determine plankton stoichiometry in mixotrophic plankton food webs

PC Ho, CW Chang, FK Shiah, P.L. Wang, CH Hsieh, Ken Haste Andersen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of light and nutrient supply in subtropical freshwater and marine systems. We found a unimodal body size-C:N ratio pattern with a maximum C:N ratio at ~50 µm diameter in marine and freshwater systems. Moreover, the variation in C:N ratios is mainly explained by body size, followed by light intensity and nutrient concentration. To investigate the mechanisms behind this unimodal pattern, we constructed a size-based plankton food web model in which the trophic strategy and C:N ratio is an emergent result. Our model simulations reproduce the unimodal pattern with C:N ratio of photoautotrophs ≤ 50 µm increasing with body size due to increase of photosynthetic carbon, whereas C:N ratios of organisms > 50 µm decreases with size due to decreasing photoautotrophic but increasing heterotrophic uptake. Based on our field observations and simulation, we extend the classic “light-nutrient” theory that determines plankton C:N ratio to include body size and trophic strategy dependency. We conclude that body size and size-dependent uptake of resources (light, nutrients and prey) determine plankton stoichiometry at various light and nutrient supplies.
Original languageEnglish
JournalAmerican Naturalist
Number of pages66
ISSN0003-0147
DOIs
Publication statusAccepted/In press - 2020

Keywords

  • Ecological stoichiometry
  • Trophic strategy
  • Mixotrophy
  • Size-based resource affinity

Cite this

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title = "Body size, light intensity and nutrient supply determine plankton stoichiometry in mixotrophic plankton food webs",
abstract = "Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of light and nutrient supply in subtropical freshwater and marine systems. We found a unimodal body size-C:N ratio pattern with a maximum C:N ratio at ~50 µm diameter in marine and freshwater systems. Moreover, the variation in C:N ratios is mainly explained by body size, followed by light intensity and nutrient concentration. To investigate the mechanisms behind this unimodal pattern, we constructed a size-based plankton food web model in which the trophic strategy and C:N ratio is an emergent result. Our model simulations reproduce the unimodal pattern with C:N ratio of photoautotrophs ≤ 50 µm increasing with body size due to increase of photosynthetic carbon, whereas C:N ratios of organisms > 50 µm decreases with size due to decreasing photoautotrophic but increasing heterotrophic uptake. Based on our field observations and simulation, we extend the classic “light-nutrient” theory that determines plankton C:N ratio to include body size and trophic strategy dependency. We conclude that body size and size-dependent uptake of resources (light, nutrients and prey) determine plankton stoichiometry at various light and nutrient supplies.",
keywords = "Ecological stoichiometry, Trophic strategy, Mixotrophy, Size-based resource affinity",
author = "PC Ho and CW Chang and FK Shiah and P.L. Wang and CH Hsieh and Andersen, {Ken Haste}",
year = "2020",
doi = "10.1086/707394",
language = "English",
journal = "American Naturalist",
issn = "0003-0147",
publisher = "University of Chicago Press",

}

Body size, light intensity and nutrient supply determine plankton stoichiometry in mixotrophic plankton food webs. / Ho, PC; Chang, CW; Shiah, FK; Wang, P.L.; Hsieh, CH; Andersen, Ken Haste.

In: American Naturalist, 2020.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Body size, light intensity and nutrient supply determine plankton stoichiometry in mixotrophic plankton food webs

AU - Ho, PC

AU - Chang, CW

AU - Shiah, FK

AU - Wang, P.L.

AU - Hsieh, CH

AU - Andersen, Ken Haste

PY - 2020

Y1 - 2020

N2 - Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of light and nutrient supply in subtropical freshwater and marine systems. We found a unimodal body size-C:N ratio pattern with a maximum C:N ratio at ~50 µm diameter in marine and freshwater systems. Moreover, the variation in C:N ratios is mainly explained by body size, followed by light intensity and nutrient concentration. To investigate the mechanisms behind this unimodal pattern, we constructed a size-based plankton food web model in which the trophic strategy and C:N ratio is an emergent result. Our model simulations reproduce the unimodal pattern with C:N ratio of photoautotrophs ≤ 50 µm increasing with body size due to increase of photosynthetic carbon, whereas C:N ratios of organisms > 50 µm decreases with size due to decreasing photoautotrophic but increasing heterotrophic uptake. Based on our field observations and simulation, we extend the classic “light-nutrient” theory that determines plankton C:N ratio to include body size and trophic strategy dependency. We conclude that body size and size-dependent uptake of resources (light, nutrients and prey) determine plankton stoichiometry at various light and nutrient supplies.

AB - Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of light and nutrient supply in subtropical freshwater and marine systems. We found a unimodal body size-C:N ratio pattern with a maximum C:N ratio at ~50 µm diameter in marine and freshwater systems. Moreover, the variation in C:N ratios is mainly explained by body size, followed by light intensity and nutrient concentration. To investigate the mechanisms behind this unimodal pattern, we constructed a size-based plankton food web model in which the trophic strategy and C:N ratio is an emergent result. Our model simulations reproduce the unimodal pattern with C:N ratio of photoautotrophs ≤ 50 µm increasing with body size due to increase of photosynthetic carbon, whereas C:N ratios of organisms > 50 µm decreases with size due to decreasing photoautotrophic but increasing heterotrophic uptake. Based on our field observations and simulation, we extend the classic “light-nutrient” theory that determines plankton C:N ratio to include body size and trophic strategy dependency. We conclude that body size and size-dependent uptake of resources (light, nutrients and prey) determine plankton stoichiometry at various light and nutrient supplies.

KW - Ecological stoichiometry

KW - Trophic strategy

KW - Mixotrophy

KW - Size-based resource affinity

U2 - 10.1086/707394

DO - 10.1086/707394

M3 - Journal article

JO - American Naturalist

JF - American Naturalist

SN - 0003-0147

ER -