Distribution of Charophyte Oospores in the Curonian Lagoon and their Relationship to Environmental Forcing

Lack of knowledge about distribution of charophyte fructifications and importance of environmental conditions in the Baltic Sea coastal waters fostered us to assess the spatial-temporal patterns of oospore bank in relationship with environmental factors in the Curonian Lagoon (Lithuanian part). We mapped the distribution of oospores in 2017-2019. The importance of environmental factors was determined by the cluster analysis and boosted regression trees. Four oospores species were recorded up to 4 m depth. The highest mean densities (58,000 ind center dot m(-2)) of viable fructifications were found along the eastern shore, where the densest charophyte stands were recorded. Viable fructifications showed a clear pattern of filling the oospore bank after the vegetation season and a depletion during the summer as they germinated. The distance from charophyte stands, salinity, bottom slope aspect, and wave exposure were the most important environmental variables. Full fructifications mostly occurred within 1.5 salinity.

Automated summary

The study found that the distribution and survival of charophyte fructifications in the Curonian Lagoon are influenced by environmental factors, with the eastern shore having the highest density. Fructifications showed a decrease during the summer germination period. Environmental variables such as distance from charophyte stands, salinity, bottom slope aspect, and wave exposure play important roles in determining the distribution of viable fructifications.