INVESTIGADORES
UNREIN Fernando
artículos
Título:
Picoplankton abundante and cytometric group diversity along a trophic and latitudinal lake gradient
Autor/es:
SCHIAFFINO, M. R.; GASOL, J. M.; IZAGUIRRE, I.; UNREIN, F.
Revista:
AQUATIC MICROBIAL ECOLOGY
Editorial:
INTER-RESEARCH
Referencias:
Lugar: Oldendorf/Luhe; Año: 2013 vol. 68 p. 231 - 250
ISSN:
0948-3055
Resumen:
The Picoplankton (PP) is responsible for the major part of C processing, nutrient recycling, planktonic respiration as well as primary production in most aquatic environments. However, not much is known about the factors that regulate its total abundance and community structure. Using the capability of flow cytometry (FC) to detect particles based on their pigments and nucleic-acid content, we described and quantified the photosynthetic (PPP: photosynthetic PP) and the heterotrophic (basically HB: heterotrophic bacteria) populations (or groups) composing PP in 32 water bodies located along a trophic and latitudinal gradient in the Argentinean Patagonia (along 1100 km and 10° of latitude), so that it was possible to determine flow-cytometrically defined community structures. We set to identify the environmental variables regulating total PP abundance, group structure and cytometric diversity. We identified a total of 28 different cytometric populations within the HB, 14 of phycoerythrin (PE)- rich picocyanobacteria (Pcy), 8 of phycocyanin (PC)-rich Pcy, and 41 of picoeukaryotes (Peuk) in the different water bodies, with average 3.9 HB and 4.6 PPP groups per water body. We found a strong influence of environmental factors (related to trophic status, e.g. chlorophyll a -chl a, pH, and oxygen) and a less marked effect of latitude on PP structure. HB and PPP abundances decreased towards higher latitudes but their cytometric diversity did not, whereas HB and PPP (PC-rich Pcy and Peuk) abundances together with PPP diversities increased with higher values of chl a. PE-rich Pcy were more represented in oligotrophic lakes, while PC-rich Pcy in eutrophic ones. The relative contribution of PE-rich Pcy to total Pcy decreased with chl a, whereas the relative contribution of PC-rich Pcy and the number of PC-rich cytometric populations increased with chl a values. Peuk prevailed over Pcy with increasing trophic status and light attenuation, whereas HB prevailed over PPP with increasing trophy. The described PP community structure shifts along the gradient of water bodies studied reflect the environmental and biological properties of the ecosystems and also indicate the adequacy of FC- derived PP community structure for providing information on the ecological status of the ecosystems.