Homeostasis and non-linear shift in the stoichiometry of P-limited planktonic communities
Giménez-Grau, Pau (Aarhus University. Department of Biology)
Felip, Marisol (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Zufiaurre, Aitziber (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Pla-Rabes, Sergi (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Camarero, Lluís (Centre d'Estudis Avançats de Blanes)
Catalán, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Date:	2020
Abstract:	Planktonic communities are naturally subjected to episodic nutrient enrichments that may stress or redress the imbalances in limiting nutrients. Human-enhanced atmospheric nitrogen deposition has caused profound N:P imbalance in many remote oligotrophic lakes in which phosphorus has largely become limiting. These lakes offer an opportunity to investigate the relationship between the changes in plankton stoichiometry, productivity, and community structure occurring during nutrient fluctuations in P-limited conditions. We performed P (PO3-4) and N (NH+4 or NO-3) pulse additions to the summer epilimnetic community of an ultraoligotrophic lake using self-filling ~100-L enclosures and analyzed the response to varying P availability, N:P imbalance, and N source. Seston C:N:P proportions remained fairly unchanged to P additions that were within the range of values seasonally found in the lake. However, the seston N:P ratio abruptly shifted and approached Redfield's proportions at P additions typical of mesotrophic conditions that provided non-limiting conditions. N surplus did not affect seston C:N:P proportions. The patterns of seston N:P stability and shift were similar for both N sources. In contrast, productivity was highly sensitive to low and medium P additions and decelerated at high P additions. Phytoplankton biomass dominated particulate organic matter. The autotrophic community differentiated almost linearly across the P gradient. Chrysophytes' dominance decreased, and diatoms and cryptophytes relative abundance increased. Nonetheless, the stoichiometry stability and non-linear shift involved large biomass proportions of the same species, which indicates that the bulk stoichiometry was related to similar physiological behavior of phylogenetically diverse organisms according to the biogeochemical context. The C:N:P seston stability in P-limited conditions-with loose coupling with productivity, nutrient supply ratios, and species dominance-and the sudden shift to Redfield proportions in P-repleted conditions suggest a complex regulation of P scarcity in planktonic communities that goes beyond immediate acclimation growth responses and might include alternative physiological and biogeochemical states.
Grants:	Ministerio de Economía y Competitividad CGL2016-80124-C2-1-P Ministerio de Economía y Competitividad BES-2014-070196 Ministerio de Economía y Competitividad CGL2010-19737 Ministerio de Educación, Cultura y Deporte AP2010-3596 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-910
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Ecological stoichiometry ; ENEX experiment ; Experimental enclosures ; Mountain lakes ; Nutrient enrichments ; Oligotrophy ; Phytoplankton ; Seston
Published in:	Ecosphere, Vol. 11, issue 9 (September 2020) , art. e03249, ISSN 2150-8925

DOI: 10.1002/ecs2.3249

Article 18 p, 3.0 MB

Material suplementari 4 p, 1.9 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles