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)

20.01.2016, Brussels Open sea waters: HELCOM’s responsibility Marine Strategy Framework Directive (MSFD)

German Environmental Agency

State Agencies of Coastal waters: national responsibility Federal states Water Framework Directive (WFD) WFD MSFD Commonalities very good • Aim: Good Ecological State (GES) Reference Value • Defined via thresholds (“target values”) good good • Based on „reference conditions“ Target Value Target Value • Nutrient load reductions as only measure moderate bad … Joint BLANO working group with all involved agencies 1. Informal workshops Informal workshop 2011 Public discussion organized by agencies 2. Joint working group ----- Workshop, IOW, Warnemünde, 29.08.2011 (GS) ... (with a pre-defined ... work order by BLANO) 2012 Symposium on inshore waters, LUNG Güstrow, 13.09.2012 (GS) Workshop, LUNG, Güstrow, 14.09.2012 (GS) 1. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH, Hamburg, 15.11.2012 (GS) 3. Public discussions a of Inproject advance ----- HELCOM climate change workshop, IOW, 05.02.2013 (GS, RF) 2. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, IOW, 06.02.2013 (GS, RF) 2013 Mini-Symposium "Marine Monitoring", LLUR Flintbek, 19.03.2013 (GS) 4. Joint scientific project 3. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, 26.03.2013 (GS) 4. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, 28.10.2013 (GS, RF) (funded by BMBF) ----- Symposium on inshore waters, LUNG Güstrow, 20.11.2013 (RF) 5. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, LUNG Güstrow, 13.02.2014 (GS, RF) 5. Scientific paper 2014 Mini-Symposium "Marine Monitoring", LLUR Flintbek, 26.03.2014 (GS) Symposium on marine environment, BSH Hamburg, 03.06.2014 (RF) (in English) AG Nährstoff-Referenz- und Orientierungswerte North Sea, BSH Hamburg, 08.07.2014 (GS) ----- 6. UAG Nährstoffreduktionsziele & Eutrophierung Baltic Sea, BSH Hamburg, 15.09.2014 (RF) Symposium on inshore waters, LUNG Güstrow, 19.11.2014 (RF)

6. Joint extensive report project Joint 2015 Mini-Symposium "Marine Monitoring", LLUR Flintbek, 05.03.2015 (GS) Fach-AG „Eutrophierung, Nährstoffe und Plankton“, DWD Hamburg, 14.07.2015 (RF) (in German) AG ‚Water quality targets North Sea‘ ----- ……. Review of present targets:  purely salinity dependent Eutrophication with one target for every water type parameters: surface concentrations of Chlorophyll a, Total Nitrogen & Phosphorus

-> Secchi Depth is missing First assessment (2009): 43 of 44 German water bodies not in GES Targets for Chlorophyll:

 2 levels  intercalibrated for open coastal waters (GER, DK, PL) Total Nitrogen (annual average) 25 250 Target [µmol/l] State [µmol/l] 20 200 15 150 10 100 5 50 0 0 Oder (River) Small Bay Southern Arkona Sea of Oder Lagoon Pomeranian Bight (HELCOM)  TN & TP targets unreachable (no motivation to start measures)  due to unrealistic ‘pristine’ loads of Oder . Used loads by Brockmann et al. (2012): 3.669 t TN /a (244 t TP/a) . Historical loads from Gadegast et al. (2012): 13.425 t TN/a (950 t TP/a) . Present loads [2000-09]: 55.000 t/a (3.200 t TP/a) New approach necessary! Demands:

 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 How to define reference conditions/ values? “high status with no, or very minor disturbance from human activities”

1. Use observations from 1960s  Sparse in space & time  Not consistent with WFD

2. Calculations based on  lack of knowledge and data ‘pristine conditions’  high uncertainties  worth pursuing?

3. Assume realistic historic situation  Most reliable (e.g. around 1880) & use an model  Consistent with WFD & MSFD to calculate targets  Model errors to be considered 1880 as reference condition

• We go back as far as possible and reliable 17% of • Land usage documented & comparable with today present loads • basis for a realistic & reachable ecological state

• German loads & Oder from catchment model MONERIS • Baltic Sea wide load reconstruction from BNI 22% of • Ignore changes in the ecosystem (e.g. macrophytes) present loads

Figures provided by J. Mahnkopf (IGB) Simulated Chlorophyll Present loads

How to deal Historical with the loads model`s uncertainty? historical / present simulated chlorophyll

 measure for the specific reaction to the different loads TP (annual)

Chlorophyll (summer)

TN Always (annual) steep gradients! Station O5

2,5 historical / present simulated chlorophyll Fits with intercalibrated target 2 Multiplication with ratio from 1,5 simulation (0.6)

1 + 50% (following

Chlorophyll [µg/l] a Chlorophyll 0,5 WFD guidance)

0 Present State Reference Value Proposed Target Present Target Natural gradients are reproduced!

new intercalibrated new targets reflect targets targets local characteristics fit with reproduced stronger present ones Present target

/l] /l] 200 State mol new proposed target

 Reachable & realistic

100 Total Nitrogen [µ Nitrogen Total

0 Oder (River) Small Bay Southern Arkona Sea of Oder Lagoon Pomeranian Bight (HELCOM) All defined demands fulfilled Demands:

 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 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

2,82 2,5 2,63 2 2 1,28 (2,5) 1 0,60

Summer Secchi Depth [m] Depth Secchi Summer 0 Bay of Greifswald Szczecin Lagoon (Small Bay) present state historical value (from literature) integrated model Review of ecological state & targets

Implementation Modifying targets of measures New proposed target for German river loads • 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 Atmospheric Waterborne River conc. Total P Chl.a Total N [t/a] TN [t/a] TN [t/a] TN [mg/l] [t/a] [µg/l] 1997-2003 32.697 13.007 19.690 4,7 526 4,5 (PLC 5.5) Allowable 21.477 10.406 11.072 2,6 526 3,6 German Loads BSAP (2013) 29.640 11.900 17.740 4,3 356 4,2

 TN-load reduction of BSAP not sufficient for coastal waters! 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 Management: catchment area Research Institutes environmental agencies

Target: river loads

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: