Progress report: Diatom analysis of Lake Latoritei
As of 30th July 2024, limnic samples of Latoritei lake (Southern Carpathians, Romania), were assessed for fossil diatom study with about 62 samples used for microscopic analysis and for further ecological assessment. A total of 500 valves were counted in each sample. About 163 taxa belonging to 49 genera were identified with age ranging from ~9950 cal. yr. BP to ~2750 cal. yr. BP. The genera with most diverse taxa are Eunotia (14), Pinnularia (11), Sellaphora (11), Gomphonema (10), Staurosira (8).
Fragilarioid like Staurosirella pinnata and Staurosira venter are consistently dominant with minimal fluctuations throughout the studied section of the core. From ~9950 cal. yr. BP, Fragilaria tenera, Discotella stelligera, D. pseudostelligera and Asterionella formosa are dominant following the Fragilarioid group up to ~8800 cal. yr. BP., of which the former two taxa mentioned are indicative of oligotrophic system and longer ice cover periods. Between 8600 to 8000 cal. yr. BP emergence of Fragilaria sp., F. tenera var. nana, Pseudostaurosira parasitica subconstricta, Odontidium hyemale and decrease in Staurosira venter reflect an impact of 8.2k short term cooling. Until ~8300 cal. yr. BP appearance of nitrophilous taxa indicates planktonic nitrogen availability.
From ~7800 to ~5000 cal. yr. BP, dominant taxa Tabellaria floculosa, Odontidium spp., Pinnularia subgibba, Planothidium lanceolata, showing a fluctuation between acidophilous to alkaliphilous groups is a plausible result of climatic oscillation or regional level changes. From about ~3500 to ~2700 cal. yr. BP, increase in Navicula radiosa, Gogorevia exilis, Pseudostaurosira microstriata, Sellaphora laevissima indicative of high nutrient enriched and alkaline system is observed.