Intercalibration of Opportunistic Algae Blooms

1. Intercalibration of Opportunistic Algae Blooms Robert Wilkes Environmental Protection Agency, John Moore Road, Castlebar, Co. Mayo.

2. Transitional Waters- FR, IE, PT, UK Member states with assessment tool and opportunistic green algal accumulations: France Ireland Portugal United Kingdom

3. Intercalibration of Opportunistic Algae Blooms • Assessing large accumulation of Opportunistic green macroalgae indicative of eutrophication • Blooms assessed nationally for WFD and other purposes • WFD compliant tools developed and intercalibrated in IC phase 1 (UK, DE and IE) • Tools were designed to assess complex eutrophication pressures • MS tools are all roughly similar • Assess spatial are of suitable intertidal covered by green algal mats • Other sub metrics included in some tools (biomass, entrainment etc.)

4. Transitional Waters- FR, IE, PT, UK Collection of IC dataset

5. Transitional Waters- FR, IE, PT, UK • Feasibility check • Typology- Yes, for Soft intertidal sediments in TW-NEA 11 • Pressures, national methods vs pressure relationship • Pressure relationship looks at only measurement of a single pressure (Winter DIN). It does not take other compounding factors into account e.g. Turbidity, Flushing … • The pressure relationship varies between each MS and while low is significant • FR r2= 0.43 p< 0.001 • IE and UK r2 = 0.3 p< 0.001 • All MSs ICM r2 = 0.2 p<0.001 • The Portuguese method cannot be directly validated against a pressure gradient as there is only 1 WB assessed over a number of years. However the Portuguese method is ~ the same as the ICM and the ICM has been shown to significantly respond to nutrient pressure. Therefore we can infer that this relationship should hold for PT. • Other pressure relationships were investigated but no significant relationships were found.

6. Transitional Waters- FR, IE, PT, UK

7. Transitional Waters- FR, IE, PT, UK • Design and application of the IC procedure • Option • Option 2 - UK and IE use same 5-metric tool, FR using a similar tool to UK and IE but do not use some of the metrics, PT only assess spatial extent and cover. • Common Metric • All MSs assess the percentage of the available intertidal area covered with opportunistic macroalgal. ICM boundaries the same for all MSs • Correlation of ICM with MS method

8. Transitional Waters- FR, IE, PT, UK • Design and application of the IC procedure • ICM vs pressure • R2= 0.1886, p= 0.0001

9. Transitional Waters- FR, IE, PT, UK • Benchmarking • Benchmark standardisation was done using the spreadsheets developed by Nemitz, Willby and Birk version 1.24 (March 2011). • Initially undertaken using the standard approach with Benchmark sites selected by MSs as those with lowest pressures • Due to a low number of benchmark sites and poor data availability, the continuous benchmarking approach was attempted. • The procedure involved using General Linear Modelling to calculate offset values for the ICM vs Pressure relationship for each MS.

10. Transitional Waters- FR, IE, PT, UK • IC results • CBM

11. Transitional Waters- FR, IE, PT, UK • Some MSs not happy with the statistical approach (poor relationships, small dataset, inadequate pressure relationship…) • Suggested changes not an accurate reflection of the ecology? • Using the standard option 2 benchmarking approach, no changes are required

12. Transitional Waters- FR, IE, PT, UK

13. Coastal Waters- DE, FR, IE, UK Member states with assessment tool and opportunistic green algal accumulations: France Ireland Germany United Kingdom

14. Coastal Waters- DE, FR, IE, UK • Feasibility check • Typology • Yes for each MS in NEA1/26, DE are the only MS with data for NEA3/4 so intercalibration in this type is not feasible • Some issue as UK/IE consider slightly different waterbody types than FR/DE • Assessment concept • UK and IE use in situ sampling and included biomass in their tool • DE and FR use remote sensing • Although methodologies differ between MS the general concept of assessing spatial cover of algal growth is the same across each MS

15. Coastal Waters- DE, FR, IE, UK • Feasibility check • Pressures, national methods vs pressure relationship • Only a single pressure assessed in these investigations- Winter DIN • Each MS assessed opportunistic macroalgae as indicators of eutrophication pressure • DE, insufficient spread of sites, all at similar pressure so no clear relationship • FR, significant relationship • IE, few sites and all at High/Good end of gradient • UK, Weak relationship for national method but good for the ICM • UK and IE assessed together as they use the same tool- poor national method relationship but strong ICM relationship

16. Coastal Waters- DE, FR, IE, UK Collection of IC dataset • Sufficient gradient of pressure classes found at GIG level but not MS level • UK and IE grouped together for analyses, both use exactly the same tool and boundaries

17. Coastal Waters- DE, FR, IE, UK • Design and application of the IC procedure • Option • Option 2 - IE, UK use same tool, DE and FR use different methods. All use ‘amount of Available intertidal area covered by algae’ in assessment so this was chosen as a common metric. • Common Metric • All MSs use percentage of AIH covered by algae in assessment. For DE this is the only assessment criteria in their method. • Some national differences in ICM • Correlation of ICM with MS method

18. Coastal Waters- DE, FR, IE, UK • Common Metric • The ICM is based on the percentage cover of available intertidal area. • Data is based on remote sensing for DE/FR and in situ for UK/IE. For this reason there are different boundaries for the two methodologies. • In situ H/G <5%; G/M 15% • Remote H/G <0.5%; G/M 1.5% • The differences in boundaries are also indicative of differing errors-limits between remote and in situ mapping techniques • While this may mean that this is not a ‘true’ ICM it is the only way to do the intercomparison across all 4 MSs.

19. Coastal Waters- DE, FR, IE, UK • Common Metric • Another option is to do two intercalibrations- 1 for in situ methods UK/IE (option 1) and 1 for remote methods DE/FR (option 2). • The large difference between the two groups is due to a number of factors: • Different shore types among MSs not accounted for by typology • Different resolution of assessment techniques • UK/IE use biomass which helps to distinguish between thin cover and large accumulations allowing for a greater percentage cover

20. Coastal Waters- DE, FR, IE, UK • Design and application of the IC procedure • ICM vs pressure (Winter DIN concentration in µM) r2= 0.4991, p< 0.001 ICM- EQR DIN µM

21. Coastal Waters- DE, FR, IE, UK • Benchmarking • Benchmark standardisation was done using the spreadsheets developed by Nemitz, Willby and Birk version 1.24 (March 2011). • Due to a lack of benchmark sites for DE and poor data availability, the continuous benchmarking approach was used. • The procedure involved using General Linear Modelling to calculate offset values for the ICM vs Pressure relationship for each MS.

22. Coastal Waters- DE, FR, IE, UK • IC results- Continuous Benchmarking

23. Coastal Waters- DE and FR, UK and IE • IC results • France and Germany- Continuous Benchmarking • Ireland and UK • Option 1- same tool, same boundaries and same assessment methodology

24. Coastal Waters- DE, FR, IE, UK

25. Final Conclusion • Small datasets • Poor pressure relationships • Not enough data for more comprehensive pressure assessment • Different physical conditions interfere with pressure gradients • Statistics not designed for such small datasets so results vary greatly with slight changes • Some MS not happy with proposed boundaries suggested from analyses done with low statistical significance