Joint effect of phosphorus limitation and temperature on alkaline phosphatase activity and somatic growth in Daphnia magna

Marcin W. Wojewodzic, Marcia Kyle, James Elser, Dag O. Hessen, Tom Andersen

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Alkaline phosphatase (AP) is a potential biomarker for phosphorus (P) limitation in zooplankton. However, knowledge about regulation of AP in this group is limited. In a laboratory acclimation experiment, we investigated changes in body AP concentration for Daphnia magna kept for 6 days at 10, 15, 20 and 25°C and fed algae with 10 different molar C:P ratios (95-660). In the same experiment, we also assessed somatic growth of the animals since phosphorus acquisition is linked to growth processes. Overall, non-linear but significant relationships of AP activity with C:P ratio were observed, but there was a stronger impact of temperature on AP activity than of P limitation. Animals from the lowest temperature treatment had higher normalized AP activity, which suggests the operation of biochemical temperature compensation mechanisms. Body AP activity increased by a factor of 1. 67 for every 10°C decrease in temperature. These results demonstrate that temperature strongly influences AP expression. Therefore, using AP as a P limitation marker in zooplankton needs to consider possible confounding effects of temperature. Both temperature and diet affected somatic growth. The temperature effect on somatic growth, expressed as the Q 10 value, responded non-linearly with C:P, with Q 10 ranging between 1. 9 for lowest food C:P ratio and 1. 4 for the most P-deficient food. The significant interaction between those two variables highlights the importance of studying temperature-dependent changes of growth responses to food quality.

Original languageEnglish (US)
Pages (from-to)837-846
Number of pages10
JournalOecologia
Volume165
Issue number4
DOIs
StatePublished - Apr 2011

Keywords

  • Cladocerans
  • Compensation mechanisms
  • EQ
  • Growth
  • Q value

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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