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The threshold elemental ratio of carbon and phosphorus of Daphnia magna and its connection to animal growth

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journal contribution
posted on 17.12.2018, 15:04 by Hamza K. Khattak, Clay Prater, Nicole D. Wagner, Paul C. Frost
The growth of animal consumers is afected by the balance of elements in their diet with the transition between limitation by one element to another known as the threshold elemental ratio (TER). Precise estimates of TERs with known levels of uncertainty have yet to be generated for most zooplankton consumers. We determined the TER for carbon (C) and phosphorus (P) in for a common lake zooplankter, Daphnia magna, using experimental measurements and theoretical considerations. Daphnia growth responses to food C:P ratios across a relatively narrow range (80–350) generated an empirical estimate of TERC:P of 155±14. While this TER matched our modelled estimate of TERC:P (155±16), it was lower than previous estimates of this dietary transition point. No threshold was found when we examined daphnid body C:N or C:P ratios in response to changing food C:P ratios, which indicates P-limitation at even lower food C:P ratios. Our results provide strong evidence that D. magna is likely to experience acute P-limitation when food C:P ratios exceed even relatively low ratios (~155). Our model further demonstrated that while physiological adjustments may reduce the likelihood of P-limitation or reduce its intensity, these changes in animal material processing would be accompanied by reduced maximum growth rates.

Funding

Support for this research was provided by the Natural Sciences and Engineering Research Council of Canada through funds provided to Hamza Khattak and Paul Frost.

History

School

  • Social Sciences

Department

  • Geography and Environment

Published in

Scientific Reports

Volume

8

Issue

1

Citation

KHATTAK, H.K. ... et al., 2018. The threshold elemental ratio of carbon and phosphorus of Daphnia magna and its connection to animal growth. Scientific Reports, 8: 9673.

Publisher

© The authors. Published by Springer Nature

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date

05/06/2018

Publication date

2018

Notes

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

eISSN

2045-2322

Language

en

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