KOPPRIO German Adolfo
Stable isotope and fatty acid markers in plankton assemblages of a saline lake: seasonal trends and future scenario
KOPPRIO, G. A.; LARA, R. J.; MARTÍNEZ, ANA; FRICKE, A.; GRAEVE, M.; KATTNER, G.
JOURNAL OF PLANKTON RESEARCH
OXFORD UNIV PRESS
Lugar: Oxford; Año: 2015
Plankton fractions from a saline lake in Argentina were studied in a combined trophic marker approach. A strong seasonality of biomarkers was characteristic for the different fractions, particularly the variations of the 18:4(n-3) and 20:4(n-3) fatty acids and the δ13C values. The primary production in the lake was mainly driven by diatoms, reflected by the close relation of δ13C, chlorophyll a and fatty acid markers of diatoms. The combined approach of δ13C and 20:4(n-3) allowed inferring processes in the lipid metabolism of the copepod Boeckella poopoensis. The polyunsaturated fatty acid 22:6(n-3) and the δ15N separated the trophic levels in this food web with copepods at higher trophic level. Nutritional stress and omnivory of B. poopoensis explained partially the δ15N variations in mesozooplankton. The δ15N signature was probably driven by cyanobacteria in the microplankton and by microbial processes in the nanoplankton fraction. Warmer temperatures may favour the saturation of fatty acids in microalgae and the abundance of plankton groups richer in saturated fatty acids. The tendency to unsaturation in mesozooplankton at colder temperatures was probably influenced by diet and metabolic requirements. A future temperature increase and eutrophication-like processes may increase the importance of cyanobacterial and bacterial markers under climate change scenarios.