Strict stoichiometric homeostasis of Cryptomonas pyrenoidifera (Cryptophyceae) in relation to N:P supply ratios

  • Eloísa Ramos Rodríguez | eloisa@ugr.es Granada University, Spain.
  • Carmen Pérez-Martínez Granada University, Spain.
  • José María Conde-Porcuna Granada University, Spain.

Abstract

A common freshwater cryptophyte, Cryptomonas pyrenoidifera, was cultivated in batch-cultures to analyze intraspecific variation in elemental stoichiometry along a broad gradient of pulsed phosphorus (P) enrichment during the early acclimation period and to determine the immediate homeostatic capacity of the nitrogen-to-phosphorus (N:P) ratio of this alga when nutrients are at saturating levels. Experimental results revealed that nitrogen (N) and P cell quotas significantly increased with increasing P concentration. However, despite the wide range of N:P ratios in the medium, Cryptomonas N:P ratios were highly stable at higher P-level treatments, indicating a highly conservative behavior and suggesting strict elemental homeostasis when nutrients are at saturating levels. The strictly homeostatic N:P ratio appears to be attributable to their high potential for a fast luxury consumption of both N and P after a brief and intense episode of increased resource availability and to physiological limits on their nutrient storage capacity. Most importantly, the N:P biomass ratio at nutrient saturating levels converged around 11:1, which was the observed ratio of maximum internal cell quotas for N and P (i.e. Qmax,N:Qmax,P) under the prevailing experimental conditions. This value is particularly informative for C. pyrenoidifera because it represents cell storage quotients and may be a taxon-specific evolutionary optimum, providing a reference point to infer the grade of nutrient-limitation. The experimental data give ranges of variation in C. pyrenoidifera elemental composition permitting, among others, proper parameterization of cryptophyte stoichiometry models.

Dimensions

Altmetric

PlumX Metrics

Downloads

Download data is not yet available.
Published
2016-11-15
Info
Issue
Section
Original Articles
Keywords:
Cryptomonas pyrenoidifera, ecological stoichiometry, elemental homeostasis, optimal N, P ratio, luxury storage capacity
Statistics
  • Abstract views: 1941

  • PDF: 541
  • Supplementary: 240
  • HTML: 1271
How to Cite
1.
Ramos Rodríguez E, Pérez-Martínez C, Conde-Porcuna JM. Strict stoichiometric homeostasis of Cryptomonas pyrenoidifera (Cryptophyceae) in relation to N:P supply ratios. J Limnol [Internet]. 2016Nov.15 [cited 2020Nov.25];76(1). Available from: https://jlimnol.it/index.php/jlimnol/article/view/jlimnol.2016.1487