Lake levels and trophic states of a shallow lake from the southern Pampa plain, Argentina

What is it about?

Based on a conceptual framework, we propose that the lake level defines the water column mixing conditions, affecting internal lake processes and determining the transparency of lake water. The shift between alternative states is reconstructed for the last ~4800 years. Four main lake stages have been recognized, although short term shifts characterize all stages. A turbid phytoplankton-dominated state prevailed between ~4700-4500 cal yr before present (BP). Drier conditions and low lake levels pushed the lake to a clear state until 2000 cal yr BP. Afterwards the lake switched back to a turbid state, and these conditions persisted until ~200 cal yr BP. In the last 200 years, the lake switched back and forth between clear and turbid states. The latter represents the modern conditions of the lake since ~1950 AD. These shifts can be attributed mainly to climatic drivers.

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Why is it important?

Since the lakes of the Pampas are considered common pool resources used for recreational, residential, touristic and intensive agricultural activities, knowledge of past trophic states and the understanding of its dynamics can help to decision-making and planning to define restoration and conservation efforts.

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