Subrecent charophyte flora from the Pheneos palaeolake (Greece): Palaeoecological implications

Abstract

Herein, the late Quaternary charophyte flora from the Pheneos palaeolake in north Peloponnese (Greece) is examined for the first time. The Pheneos palaeolake was located in the south region of the Pheneos polje, where late Quaternary relict shoreline segments are still preserved. These shorelines correspond to the fluctuation of the water level at different periods reflecting the polje’s successive flooding and draining. Sediment sampling was conducted at 4 levels representing ancient shorelines of the lake. Up to five charophyte taxa have been identified and illustrated based on parautochtonous oospores and gyrogonites i.e., Nitella cf. hyalina, Sphaerochara prolifera, Chara vulgaris, Chara sp. and Nitellopsis obtusa. The distribution of the flora within the four studied levels allows the distinction of three different palaeoenvironmental conditions that prevailed at the paleolake´s margins during the late Quaternary. The occurrence of S. prolifera in the lowest elevation level indicates the prevalence of ephemeral annual flooding conditions of the lake´s margin. N. obtusa has been recovered from both the lowest and the upper lowest levels reflecting permanent, oligohaline, oligotrophic, and cold-water conditions. Chara vulgaris and Chara sp. are present in the uppermost two levels reflecting less permanent and oligotrophic conditions. The distribution of the charophyte flora in the Pheneos palaeolake suggests major changes in the palaeoecological conditions of the lake ranging from permanent, cold and oligotrophic to ephemeral and more eutrophic.