The plankton communities from peat bog pools: Structure, temporal variation and environmental factors

QUIROGA, M. V.; UNREIN, F.; GONZÁLEZ GARRAZA, G.; KÜPPERS, G.C.; LOMBARDO, R.; MARINONE, M.C.; MENU MARQUE, S.; VINOCUR, A.; MATALONI, G.

JOURNAL OF PLANKTON RESEARCH

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2013 vol. 35 p. 1234 - 1253

0142-7873

This is the first characterization of the structure and temporal variation of the planktoncommunities comprising the complete food web in five peat bog pools related toenvironmental factors over two consecutive ice-free periods in Tierra del Fuego(548S). Remarkably, picophytoplankton was composed solely of eukaryotic cells, surpassingthe dominance expectations for these acidic water bodies, whereas testaceanswere virtually absent, even as tychoplankters. Abundances of the different planktoniccommunities were slightly higher than those reported for Northern Hemispherepeat bogs and humic lakes. Mixotrophic nutrition prevailed among nano- andmicrophytoplankters, a strategy also common in humic lakes. The structures inspring of the planktonic communities were similar. In contrast, in late summer therewere differences in the abundance and biomass of the different trophic compartmentsamong small, shallow water bodies and large ones. These seem to be dictatedby distinct pool size-driven patterns of water temperature variation. A general shiftin the control of heterotrophic flagellates abundance in the pools occurred, changingfrom bottom-up regulation in spring to top-down control in late summer related totemperature-dependant variations in zooplankton abundance and composition. Wehypothesize that changes in the trophic interactions affecting the entire food weboccur over the open water period in these aquatic ecosystems, and that these are dictatedby pool morphometry and related abiotic features.