Intensive study of freshwater red algae (Rhodophyta) in Finland

Freshwater red algae (Rhodophyta) were studied in Central Finland by examining 2224 rivers and brooks during the open water periods of the years 2012-2015 with supplementary sampling in S- and SW-Finland, the W-coast rivers and Lapland. A total of 1957 records of algae were made. Approximately 56.2% of the studied locations had 1-6 taxa. The total taxa collected were 25, with 5 taxa new to Finland. While sampling, ecological variables were recorded and measured. The most common taxa were Batrachospermum gelatinosum (37.0%), Sheathia arcuata (10.7%), Audouinella hermannii (11.2%) and Sirodotia suecica (7.0%). Lemanea spp. (9.9%) occurred in larger rivers. Most records were from July and August, but some also in winter months. From the most rare taxa, Lemanea condensata was found in Lapland rivers, Batrachospermum vogesiacum in acid, dystrophic rivers in Central Finland, B. atrum in 7 eutrophic rivers, Kumanoa globospora in 6 rivers of Central Finland, Batrachospermum elegans in 6 and K. virgatodecaisneana in 5 harder-water rivers of SW-Finland.