Polsko-Norweski Fundusz Badań Naukowych / Polish-Norwegian Research Fund LakeNAverageSD Average relative error of individual measurement Kiełpińskie 1312,51790,2601490,021 Kiełpińskie 2313,73780,5966330,043 Kiełpińskie 3313,92890,6174260,044 Lidzbarskie 1356,72894,7375440,084 Lidzbarskie 2343,57332,7263980,063 Lidzbarskie 3344,15115,2316530,118 Rumian 1342,36892,7958490,049 Rumian 2336,54671,9384870,044 Rumian 3342,21333,6045710,082 27 0,0557 Error of the chlorophyll a assessment