1. Lakes - Central GIG progress report July 2004
Presented by Sandra Poikane Joint Research Centre Institute for Environment and Sustainability Inland and Marine Waters Unit

2. 12 countries Belgium Czech Republic Denmark Estonia France Germany
Hungary
Latvia
Lithuania
Netherlands
Poland
Slovakia
United Kingdom

3. Central GIG - Lakes
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4. Common IC types Lowland, very shallow, calcareous,
Lowland, shallow, stratified, calcareous
Lowland,shallow , siliceous, vegetation dominated by Lobelia

5. Discussion on Intercalibration parameters
Chlorophyll a
Phytoplankton – species composition
Macrophyte vegetation - species composition, abundance

6. Chlorophyll a - relatively easy !
What kind of chlorophyll data to ask?
- average value of vegetation season
- maximum value of late summer
How to aggregate data ?
The mean value would be the most appropriate

7. Chlorophyll a - relatively easy !
What time period to choose ?
The vegetation period (described as April – October or 2 weeks after ice – break)
 Sampling method ?
to report the sampling methods, preferably surface sample
Analyses methods ?
to report the extraction methods, anyway data should be comparable between different methods
 How many years ?
if possible, average and maximum values for the last 5 years

8. Biomass (% of the total biomass)
Phytoplankton species composition
Which parameter ?
Abundance (cells/l)
Biomass (mg/l)
Biomass (% of the total biomass)
Numerical scale for dominant species

9. Phytoplankton species composition
to ask for 5 dominant taxa (even in case, if there are no pronounced dominants)
to choose late summer dominant species
dominance based on biovolume or considering the typical cell volume
to provide numerical scale for dominant species (see table)
species or genus level

10. Macrophyte vegetation

11. Macrophyte vegetation
5 dominant taxa and maximal colonized water depth and the covered area (in % of lake ?)
use of ECOFRAME classification of abundance (5 levels)
only submerged plants
genus or species level
based on cover of littoral of deep lakes (3 – 15 m) or whole lakes for very shallow lakes (< 3 m)

12. Common metrics for macrophyte vegetation ?
3 possibilities for a common metric:
submerged covered area
a list of indicator species which are present in reference conditions
deep lakes (>3 m): maximum colonised water depth

13. Overview Quality element Common metric possible? (Possible) indicator
Options for intercalibration
Phytoplankton biomass
yes
Chl a
1 or 2
Phytoplankton composition no 3
Submerged macrophytes abundance
1)%submerged macrophytes
2)maximum colonised water depth   2
Submerged macrophytes composition
probably
indicator macrophytes species
3, probably 2

14. Data template for chlorophyll, P, Secchi, supporting data, pressure data

15. Thank you for attention !
Deep hard light lakes (3-15 m, > 165 µS/cm, < 150 mgPt/l)