Monitoring of the growth of phytoplankton batch cultures in part 1 (dissolved organic matter release) of the microcosm experiment, Gulf of Finland, Baltic Sea

The data were collected from an experiment using phytoplankton cultures (Apocalathium malmogiense and Rhodomonas marina). The aim of the experiment was to study carbon cycling among phytoplankton and bacteria, and the effects on the dissolved organic matter (DOM) pool. The experiment was conducted at Tvärminne Zoological Station, Hanko, Finland with non-axenic unialgal phytoplankton cultures and bacteria originating from the Baltic Sea. The experiment was conducted between Dec. 2017 and Apr. 2018. The experiment consisted of two parts, the DOM release experiment (part 1) and the DOM consumption experiment (part 2). Separate triplicate batch cultures of both phytoplankton species were grown for each experiment. In the DOM release experiment the cultures were grown for over 4 months and three day-long incubations (key point incubations, KPI's) were initiated on three occasions; the first KPI at early exponential growth phase and the second and third KPI's when the phytoplankton had grown more abundant.

This data table contains measurements collected during monitoring of the growth of phytoplankton batch cultures in part 1 of the experiment (DOM release experiment), i.e., before and in between of the KPIs. These phytoplankton cultures were used in the three key point incubations of the DOM release experiment. The variables measured during the monitoring, and included in this data file, are phytoplankton abundance, abundance of A. malmogiense cells with lower chlorophyll a fluorescence, percentage of phytoplankton cells with intact membranes, and optical properties of DOM. The experimental design is explained in figure 1 of the associated publication.