Pirkko Kauppila (FI), Andres Jaanus (EE) & Jakob Walve (SE) Intercalibration of chlorophyll a in BC1 and BC3, the northern Baltic Sea Pirkko Kauppila (FI), Andres Jaanus (EE) & Jakob Walve (SE) ECOSTAT meeting Ispra, March 20, 2012

Common types: BC1 & BC3 Sweden BC1 BC1: The Quark and the Bothnian Sea BC3: Outer parts of the Askö archipelago (SE), the Archipelago Sea FI) and the western Gulf of Finland (FI and EE). Finland BC3 BC3 Estonia

Note differences in depth relationships!

IC of chlorophyll a between FI and SE in BC1 in the Bothnian Sea and the Quark

Comments from JRC for BC1 Univariate test of Signif. for log Chl Based on GLM, the data did not reveal significant difference between FI and SE. EQR needs to be measured as a distance from the same reference value (mean value = 1.3 µg L-1). FI and SE have different boundary setting in Option 1, meaning that compliance checking was needed. SS Freedom MS F p Intercepth 0.57 1 3.26 0.075 Log TN 0.79 4.54 0.036 0.08 0.45 0.51 Error 11.8 68 0.17

Harmonized class boundaries in BC1 between SE and FI µg L-1 EQR Ref H/G G/M M/P P/B FI 1.3 2.0 2.2 3.3 6.5 0.65 0.59 0.4 0.2 SE 1.5 0.87 Finnish class boundaries are a little bit higher mainly due to differences in depth relationships, surface temperatures in July to August, and the main direction of surface currents. Comment from JRC: ”You can keep your proposed chlorophyll concentrations but you have to translate these into different EQR values.”

IC of chlorophyll a between FI and EE in BC3 in the outer parts of Archipelago Sea and the western Gulf of Finland

Comments from JRC for BC3 BC3 between FI and EE Parameter estimates (FI & EE) There is a significant difference between FI and EE. FI has 0.48 µg L-1 less Chl than EE for the same TN. At a reference value of 1.8 mg L-1 of EE, FI should get 1.32 µg L-1. Level of effect Chl param. Chl STD.ERR Chl - t Chl - p Intercept 1.55 0.55 2.80 0.005 TN, µMolL-1 0.25 0.02 10.6 0.00 MS FI 0.48 0.13 3.79

Harmonized class boundaries in BC3 between FI and EE µg L-1 EQR Ref H/G G/M M/P P/B FI 1.3 1.75 2.2 3.3 6.6 0.75 0.59 0.40 0.20 EE 1.8 2.7 4.5 8.8 0.82 0.67 Comment from JRC: The highest FI can go for G/M boundary is 2.24 µg L-1.

IC of chlorophyll a between FI, EE and SE in BC3 in the outer parts of Archipelago Sea, the western Gulf of Finland and Askö archipelago