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
Member State
Number of sites or samples or data values
Biological data
Physico- chemical data
Pressure data
FR-TWOGA
19 WBs
yes
IE – OGA
9 WBs
UK – OGA
24 WBs
21 WBs
PT – BMI
1 WB over several years

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
MS Method r2 p FR
0.8834
0.0001 IE
0.821
 0.001 UK
0.7424 PT
0.9699
0.002
UK&IE
0.78

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

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, UKMS
WFD compliant
National method vs Pressure
National method vs ICM
ICM vs pressure FR
Yes
Not happy with CBM results IE
Yes (with UK) ~ UK
Yes (with IE) PT
~ by extrapolation from ICM

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
Member State
Number of sites or samples or data values
Biological data
Physico- chemical data
Pressure data
DE – OMAI
Complete intertidal area surveyed by aerial mapping
6 waterbodies (NEA1/26)
6 WB
FR-CWOGA
Complete intertidal area surveyed – 9 CWB
9 WB
IE – OGA
3 waterbodies
3 WB
UK – OGA (E&W, NI, Scot)
10 waterbodies
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
Table for Intertidal Macroalgae (CW)
Member State/Method r2 p DE 1
~is the ICM FR
0.9873
p>0 UK
0.3452
p>0.1 IE
0.7159

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= , 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, UKMS
WFD compliant
National method vs. Pressure
National method vs. ICM
ICM vs. pressure DE
Yes
~ by extrapolation from ICM FR
Not happy with results 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