Calculation of water quality targets in the south-western Baltic Sea on the edge of WFD and MSFD

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1 Calculation of water quality targets in the south-western Baltic Sea on the edge of WFD and MSFD René Friedland T. Neumann, G. Nausch, N. Wasmund, G. Schernewski (IOW & Klaipeda University) , Brussels

2 Open sea waters: HELCOM s responsibility Marine Strategy Framework Directive (MSFD) German Environmental Agency Coastal waters: national responsibility Water Framework Directive (WFD) State Agencies of Federal states

3 Commonalities Aim: Good Ecological State (GES) Defined via thresholds ( target values ) Based on reference conditions Nutrient load reductions as only measure WFD very good Reference Value good Target Value moderate MSFD good Target Value bad

4 1. Informal workshops 2. Joint working group (with a pre-defined work order by BLANO) 3. Public discussions 4. Joint scientific project (funded by BMBF) 5. Scientific paper (in English) 6. Joint extensive report (in German) Joint project In advance of a project Joint BLANO working group with all involved agencies Informal workshop Public discussion organized by agencies Workshop, IOW, Warnemünde, (GS) Symposium on inshore waters, LUNG Güstrow, (GS) Workshop, LUNG, Güstrow, (GS) 1. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH, Hamburg, (GS) HELCOM climate change workshop, IOW, (GS, RF) 2. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, IOW, (GS, RF) Mini-Symposium "Marine Monitoring", LLUR Flintbek, (GS) 3. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, (GS) 4. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, (GS, RF) Symposium on inshore waters, LUNG Güstrow, (RF) 5. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, (GS, RF) Mini-Symposium "Marine Monitoring", LLUR Flintbek, (GS) Symposium on marine environment, BSH Hamburg, (RF) AG Nährstoff-Referenz- und Orientierungswerte North Sea, BSH Hamburg, (GS) 6. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, (RF) Symposium on inshore waters, LUNG Güstrow, (RF) Mini-Symposium "Marine Monitoring", LLUR Flintbek, (GS) Fach-AG Eutrophierung, Nährstoffe und Plankton, DWD Hamburg, (RF) AG Water quality targets North Sea.

5 Review of present targets: purely salinity dependent with one target for every water type First assessment (2009): 43 of 44 German water bodies not in GES Eutrophication parameters: surface concentrations of Chlorophyll a, Total Nitrogen & Phosphorus -> Secchi Depth is missing

6 Targets for Chlorophyll: 2 levels intercalibrated for open coastal waters (GER, DK, PL)

25 20 15 10 5 Total Nitrogen (annual average) Target [µmol/l] State [µmol/l] 250 200 150 100 50 0 Oder (River) Small Bay of Oder Lagoon Southern Pomeranian Bight Arkona Sea (HELCOM) 0 TN & TP targets

7 Total Nitrogen (annual average) Target [µmol/l] State [µmol/l] Oder (River) Small Bay of Oder Lagoon Southern Pomeranian Bight Arkona Sea (HELCOM) 0 TN & TP targets unreachable (no motivation to start measures) due to unrealistic pristine loads of Oder Used loads by Brockmann et al. (2012): t TN /a (244 t TP/a) Historical loads from Gadegast et al. (2012): t TN/a (950 t TP/a) Present loads [ ]: t/a (3.200 t TP/a)

8 Demands: New approach necessary! Reachable & realistic reference conditions and target values Chlorophyll targets in agreement with intercalibrated values Singular approach for nutrients, Chlorophyll & Secchi Depth Harmonized targets for coastal waters and open sea Natural gradients from emission sources to open sea considered

9 How to define reference conditions/ values? high status with no, or very minor disturbance from human activities 1. Use observations from 1960s 2. Calculations based on pristine conditions 3. Assume realistic historic situation (e.g. around 1880) & use an model to calculate targets Sparse in space & time Not consistent with WFD lack of knowledge and data high uncertainties worth pursuing? Most reliable Consistent with WFD & MSFD Model errors to be considered

1880 as reference condition We go back as far as possible and reliable Land usage documented & comparable with today basis for a realistic & reachable ecological state German loads & Oder from

10 1880 as reference condition We go back as far as possible and reliable Land usage documented & comparable with today basis for a realistic & reachable ecological state German loads & Oder from catchment model MONERIS Baltic Sea wide load reconstruction from BNI Ignore changes in the ecosystem (e.g. macrophytes) 17% of present loads 22% of present loads Figures provided by J. Mahnkopf (IGB)

11 Simulated Chlorophyll Present loads Historical loads How to deal with the model`s uncertainty?

12 historical / present simulated chlorophyll measure for the specific reaction to the different loads

13 TP (annual) Chlorophyll (summer) TN (annual) Always steep gradients!

14 Chlorophyll a [µg/l] 2,5 2 1,5 historical / present simulated chlorophyll Multiplication with ratio from simulation (0.6) Station O5 Fits with intercalibrated target 1 0,5 + 50% (following WFD guidance) 0 Present State Reference Value Proposed Target Present Target

15 Natural gradients are reproduced! intercalibrated targets reproduced new targets reflect local characteristics stronger new targets fit with present ones

16 Total Nitrogen [µmol/l] Present target 200 State new proposed target 100 Reachable & realistic 0 Oder (River) Small Bay of Oder Lagoon Southern Pomeranian Bight Arkona Sea (HELCOM)

17 Demands: All defined demands fulfilled Reachable & realistic reference conditions and target values Chlorophyll targets in agreement with intercalibrated values Singular approach for nutrients, Chlorophyll & Secchi Depth Harmonized targets for coastal waters and open sea Natural gradients from emission sources to open sea considered

18 Summer Secchi Depth [m] Reference values fit with historical observations Chlorophyll at Kiel Bay from 1905/06 Secchi Depth at Bay of Greifswald and Small Bay of Szczecin Lagoon 2 1,28 2,5 2,63 2 (2,5) 2,82 1 0,60 0 Bay of Greifswald Szczecin Lagoon (Small Bay) present state historical value (from literature) integrated model

19 Review of ecological state & targets Implementation of measures Modifying targets

20 Statistical attempt to link loads (TN & TN/TP-ratio) to CHL.a (averaged for the south-western BS, including parts of DK & PL) Result: TN-load reduction of 34% necessary (to decrease Chlorophyll-conc. by 20%) Assuming full implementation of Gothenburg Protocol (PLC 5.5) Allowable German Loads New proposed target for German river loads Total N [t/a] Atmospheric TN [t/a] Waterborne TN [t/a] River conc. TN [mg/l] Total P [t/a] Chl.a [µg/l] , , , ,6 BSAP (2013) , ,2 TN-load reduction of BSAP not sufficient for coastal waters!

21 René Friedland (IOW), G. Schernewski (IOW & KU), G. Nausch, T. Neumann, N. Wasmund (IOW), W. Leujak (UBA), T. Petenati (LLUR), M. v. Weber (LUNG), M. Venohr, M. Gadegast, J. Mahnkopf (IGB) German environmental agencies Management: catchment area Target: river loads Research Institutes Target: inner coastal waters Target: outer coastal waters Good ecological state of the Baltic Sea Work was financed by: Supercomputing power was provided by North-German Supercomputing Alliance:

Total phosphorus. Key Message

Total phosphorus. Key Message Total phosphorus Key Message HELCOM core indicator report July 2017 For total phosphorus, 12 open sea assessment units were evaluated for the period 2011-2015, of which good status has been achieved only