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Interactive effects of dietary phosphorus and iron on Daphnia life history
Author(s) -
Lind Patrick R.,
Jeyasingh Punidan D.
Publication year - 2018
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10763
Subject(s) - daphnia , ecological stoichiometry , life history theory , biology , zooplankton , phosphorus , avian clutch size , cladocera , life history , population , reproduction , ecology , maturity (psychological) , growth rate , zoology , environmental chemistry , nutrient , chemistry , demography , psychology , developmental psychology , organic chemistry , sociology , geometry , mathematics
Food quality of freshwater consumers is often defined as the relative supply of carbon (C) to phosphorus (P) in diet. The growth rate hypothesis makes mechanistic links between P supply, ribosome biogenesis, and growth, with subsequent impacts on other life history traits such as age at maturity and clutch size. However, we know surprisingly little about the role and importance of other elements in impacting life histories of freshwater zooplankton. Because there is much evidence indicating a pivotal role for iron (Fe) in oogenesis, we hypothesized that dietary Fe content will invoke distinct effects on consumer life history compared to P. We tested this hypothesis in four species of Daphnia , by characterizing the relative impact of P and Fe on life history traits, and also measuring changes in Fe kinetics in response to dietary P and Fe. We found that while P had the largest influence on growth rate, Fe was particularly important in impacting reproductive traits. Radiotracer (Fe 55 ) analyses revealed differences in the acquisition and retention rates of Fe between two species of Daphnia . Finally, we found that P‐ and Fe‐supply driven differences in growth and reproduction had significant effects on population growth. These results indicate that Fe can constrain production of freshwater zooplankton. Understanding the interaction between the supply of P in relation to trace elements should provide a clearer picture on how stoichiometric constraints are realized in lakes.