Germanium dioxide as agent to control the biofouling diatom Fragilariopsis oceanica for the cultivation of Ulva fenestrata (Chlorophyta) Author Rautenberger, Ralf text Botanica Marina 2024 Warsaw, Poland 2024-02-26 67 2 93 100 http://dx.doi.org/10.1515/bot-2023-0075 journal article 298376 10.1515/bot-2023-0075 07feacfc-bfbc-4cf1-92b6-f6ede7497c27 1437-4323 11360456 3.1 Dose-response relationship in Fragilariopsis oceanica After 22 days of seawater cultivation in 1 l glass beakers, brown biofilms of Fragilariopsis oceanica became clearly visible on the bottom and walls of the beakers of both the control (0 mg l −1 ) and the lowest GeO 2 concentration ( 0.003 mg l −1 ) with 27.13 mg DW m −2 and 24.23 mg DW m −2 , respectively. In contrast, all GeO 2 concentrations ≥ 0.014 mg l −1 had lower diatom biomass ( 6.56 mg DW m −2 ) than the control and 0.003 mg GeO 2 l −1 ( P <0.0001, 1-way ANOVA ; Figure 2 ).