Brownification experiment in the Baltic Sea

We carried out a mesocosm experiment over 15 days to test the effect of brownification on the planktonic ecosystem. The experiment was set up in 2.2 m3 plastic bags moored outside the Tvärminne Zoological Station at the SW coast of Finland. We used four treatments, each with three replicates: control (Contr) without any manipulation; addition of a commercially available organic carbon additive called HuminFeed (Hum; 2 mg L-1); addition of inorganic nutrients (Nutr; 5.7 µM NH4 and 0.65µM PO4); and a final treatment of combined Nutr and Hum (Nutr+Hum) additions. Water samples were taken daily and measured variables included water transparency, organic and inorganic nutrient pools, chlorophyll a (Chla), primary and bacterial production and particle counts by flow cytometry. The primary data have been published in Spilling et al 2022 (link below). The file "Jomex_AllData_compilation" contains all the discrete samples, that were taken in the morning each sampling day and analyzed/measured in the laboratory. Empty cells indicate no data. See also the PDF with description of all variables with units. The zip file contains fluorescence data plus temperature and salinity from the Aquabox system that took continuous measurements from each mesocosm consecutively, i.e. measurements in a flow through system of mesocosm number 1, thereafter mesocosm number 2 etc. The files contain fluorescence based measurements of Chlorophyll a (nanoflu_chl), Phycoerythrin (unilux_pe), Phycycyanin (nanoflu_blue) temperaure and salinity (SEB45), colored dissolved organic matter (nanoflu_cdom) and photochemical efficiency QY (aquapen).