The limnological character of peat bog ponds (Tierra del Fuego, Argentina) in relation to meteorological and hydrological features

Abstract

As part of a major limnological characterisation of Rancho Hambre mire complex (Tierra del Fuego), five water bodies (bog pools) were sampled between October 2008 and April 2010 and their physico-chemical features studied in relation to meteorological, hydrological and morphometric variables. The meteorological data recorded mostly fitted within the ranges of historical records. The influence of water body size was evidenced by the higher thermic stability of the largest pool as compared to the smallest, which reflected changes in air temperature. Water levels in the pools varied according to their superficial connectivity: deep water bodies with surface inflow and/or outflow channels had the most stable water levels; but the deepest water body, which was hydrologically isolated, had the most variable water level. In an ordination of samples resulting from a Principal Component Analysis of limnological data, the first axis reflected the minero/ombrotrophic status of water bodies, while the second represented a temporal gradient separating spring (post-thawing) samples from summer samples. Inter-annual variations in weather also influenced the limnological properties of the water bodies. Our results enable us to propose an interpretative model for the limnological characterisation of the pools, which will be a valuable tool for understanding the structure and fluctuations of the planktonic communities inhabiting these systems.