1. FI: Ansa Pilke and Liisa Lepisto, Finnish Environment Institute NO: Dag Rosland, Norwegian National Pollution Control Authority Anne Lyche Solheim, Norwegian Institute for Water Research SE: Mikaela Gonzci, Swedish EPA and Eva Willen, SLU UK: Geoff Phillips and Sian Davies, Environmental Agency for England and Wales IE: Deirdre Thierney, and Wayne Trodd, Irish EPA Lakes Northern GIG Phytoplankton (chla) / Eutrophication

2. Types and participation TypeType descriptionCountries participating, LN1Lowland, mod. alk., clear, shallowNO, UK, IE LN2aLowland, low alk, clear, shallowNO, SE, FI, UK, IE LN2bLowland, low alk, clear, deepNO, UK LN3aLowland, low alk. mesohumic (30-90 mg Pt/L), shallowNO, SE, FI, UK, IE LN5aBoreal, low alk., clear, shallow (may also include high latitude lakes) NO, SE, LN6aBoreal, low alk., mesohumic, shallow (may also include high latitude lakes) NO, SE, LN8aLowland, mod alk., mesohumic, shallowNO, SE (?), FI, UK, IE

3. IC approach NGIG has used option 2 (common metric) combined with 3 (national systems), so hybrid approach

4. Data Both common GIG datasets (REBECCA) and separate MS data sets were used –Reference lake dataset (already in MS6) –Dataset of chla from all lakes (type-divided) –Dataset with phytoplankton indicator metrics (basis for dose-response curves) All datasets will be put out on Circa before the deadline for revision of MS6 report (early autumn 2006)

5. National classification methods countries, method, metrics, status CountryStatus FinlandChla and other metrics are under development SwedenChla, Vol, % Cyano, % Chryso, Div: First draft available, but will be revised according to IC results NorwayChla, Vol, %Cyano, %Chryso: First draft available, but will be revised according to IC results UKChla and other metrics are under development (almost ready?) IEChla and other metrics are under development, will be adjusted according to IC results

6. Setting of Reference conditions Common approach for setting of reference conditions: Using existing sites, supplemented with paleodata and models! Reference criteria for selection of ref. sites: <10% agriculture (most countries), No major point sources (most countries) Some additional pressure criteria (some countries) Ecological criteria (low chla or biovol, low TP), (some countries) Paleodata validation of existing ref-sites (some countries) Expert judgement (most countries) Reference lake dataset: (REBECCA dataset: next slide) Procedure: –Ref. values: Type-specific median of ref.lake chla distribution –Small range of ref.values agreed, based on intra-type differences within NGIG (humic gradient and climatic gradients from west to east: eastern part of NGIG has drier climate and more humic matter, which gives higher ref. chla)

7. Reference conditions (chla in  g/L) TypeType descr.NMeanMinMax LN1Mod Alk, shallow, clear, lowland2132.53.5 LN2aLow Alk, shallow, clear, lowland5921.52.5 LN2bLow Alk, deep, clear, lowland6421.52.5 LN3aLow Alk, shallow, humic, lowland 4732.53.5 LN5aLow Alk, shallow, clear, mid- altitude 351.5-- LN6aLow Alk, shallow, humic, mid- altitude 72-- LN8aMod Alk, shallow, humic, lowland 843.55

8. Setting of Boundaries - Procedure H/G boundary: Statistical distribution approach (REBECCA data + other national datasets) 90 th %ile of ref.lakes for clearwater lakes 75 th %ile of ref.lakes for humic lakes (due to some ref.sites with rather high chla values) Non-linear dose-response curves of phytoplankton indicators (REBECCA data) mostly < 20% change in indicator proportions of total biomass G/M boundary: Statistical distribution of chla (REBECCA data + other national datasets): difference between H/G boundary and the worst value was equally distributed for the other class boundaries using log scale intervals Non-linear dose-response curves of phytoplankton indicators (REBECCA data), using breakpoints and/or crossing points between the different indicators (see next slide) For both boundaries: Small range allowed to account for intra-type differences due to climate and humic matter Final adjustment of boundary values (mean, min and max) to give the same EQRs across the range within the type, and also the same EQRs for all types (ensure same ambition level across the range, and user-friendly, simple classification systems)

9. Non-linear dose-response curves used for boundary setting: ref., early warning, impact ind. Ref H/GG/M

10. Boundaries N=73 Max values if long retention time Min values if short retention time Alternative to using a range: Split into subtypes, but then too little data to intercalibrated Low EQR values because of generally very low chla values flat response curves for all indicators untill the threshold (previous slide)

11. Boundaries – clearwater lakes N=89 N=96 Low alk lakes (LN2) have lower values than mod alk. lakes (LN1) Deep lakes have lower G/M values than shallow lakes

12. Boundaries – humic lakes N=104 N=68 Max values if high humic content Min values if low humic content Humic lakes have higher values than clearwater lakes Low alk lakes (LN3) have lower values than mod alk lakes (LN8)

13. Boundaries – Boreal lakes N=49 N=21 Less need for range since these types are only shared by Norway and Sweden, Too little data to assess range

14. Use of IC results in national typologies/assessment systems Different approaches will be used to transform IC results into national systems: –Many national types are similar to IC types. For these types the IC boundaries will be used (within the range) –For other national types comparability with IC types will be checked –Ref.values for other national types will be compiled, using type-specific or site-specific approaches –Using the same EQRs for national types as for IC types to set boundary values for national types. This will ensure the same ambition level for all types.

15. Problems, gaps, difficulties encountered in the IC process Deviations between IC types and national types Insufficient data for some types Different indicators in different countries: i.e. chrysophytes not relevant in UK REBECCA dataset dominated by NO, FI: can response curves be trusted in other countries in NGIG (UK, IE, SE)? Too short pressure gradient in national datasets for some countries (FI, SE) cause lack of thresholds in some national dose-response curves. Can REBECCA thresholds be trusted?

16. Conclusion Type-specific chla boundaries agreed for all NGIG types The approach of using a range of boundary values, but similar EQRs across the range is considered to be a good approach for assessment of ecological status, because this ensures the same ambition level for all sites, but still allows a site-specific flexibility, and a user- friendly simple assessment system. Taxonomic metrics (indicators) will be focused in the continuation: % Cyanobacteria is possible

17. Future work for other elements MacrophytesSpring 2007 Benthic invertebrates and acidification Spring 2007 Other elements and pressures After 2007