1. Alpine GIG Lakes Progress Report 15./16.Mar 2005 Gisela Ofenböck

2. Alpine GIG – Lakes
Jun 04: 1st Meeting in Vienna
agreement of compilation of data
 ALPDAT
Feb. 05: 2nd Meeting in Munich

3. Alpine GIG – Lakes
ALPDAT
General informations (lake type, altitude …)
Informations on trophic state (TP, Secchi …)
Phytoplankton data (sampling dates per year, sampling depth; chl-a, biovolume, algal classes, dominant taxa)

4. Alpine Lake Group ALPDAT by 04.02.2004:
General informations: 97 lakes (50 IC sites, 3 non-IC types)
Information trophic state: 85 lakes
Chlorophyll-a: 155 lake-years
Total biovolume: 242 lake-years
rel. proportion of algal classes: 229 lake-years (1-20 dates/yr)
rel. proportion of Cyclotella and Planktothrix: 97 lake-years
Species lists with biovolumes of single taxa: 151 lake-years
Problem: member states of Alpine GIG not evenly represented.

5. Alpine Lake Group
Reference conditions first step: concentration on L-AL3 only, i.e. deep lakes)
reference trophic state (oligotrophic) derived from:
Data from 1930ies (defined as reference period)
Existing high status lakes (very low impact)
Paleolimnological studies

6. Alpine Lake Group Data from 1930ies lake country BV [mg l-1]
Chl-a [µg l-1]
Wörthersee AT
0.3
1.8
Millstätter See
Ossiacher See
Weißensee
Klopeiner See
0.2
1.2
Faaker See
Keutschacher See
Pressegger See
[ ]
[ ]
Afritzer See
<0.4
<2.4
Assuming Chl-a = ca. 0.6% of total biovolume.

7. Alpine Lake Group High Status lakes (1998 – 2002) lake country
BV [mg L-1]
Chl-a [µg L-1]
Weißensee AT
Attersee
0.1
Grundlsee
Altausseer See
Annecy petit FR
2.0
Königsee GE
0.45
2.5
Alpsee/Füssen
0.4
1.0
Obersee
0.5
Weitsee
1.3
Lake Bohinj SI
<0.5
<3.0

8. Alpine Lake Group Metrics for IC – under discussion Abundance/biomass
Chlorophyll-a (available for most lakes)
Total biovolume (available for most lakes in AT, GE, IT, SI, not in FR)
Taxonomic composition
Relative proportion of algal classes (based on biovolume; available in AT, GE, IT and SI)
French index (based on abundance classes; available for most lakes in all 5 countries)
Relative proportion of dominant taxa (Cyclotella, Planktothrix; available in AT, GE, IT, SI)
Brettum index (within Austrian assessment scheme)

9. Alpine Lake Group Brettum index (further developed by M. Dokulil)
Example for assessment of taxonomic compositon:
Brettum index (further developed by M. Dokulil)
Trophic indices for species (and genera)
Multiply with biovolume
 Indices for each trophic class
Highest values indicates trophic state

10. Alpine Lake Group Calculation of trophic indices for each taxon
oligo
o-m
meso eu
poly
hyper 5 4 3
Planktothrix rubescens [mg L-1] 2 1 10
100
TP [µg L-1]

11. Distribution of indices for each trophic class
Alpine Lake Group
Distribution of indices for each trophic class . 4
Königsee 2000
5 dates/yr . 3 . 2 . 1 . o l i g o m e s s l . e u
heav.eu p o l y t r o p h y

12. Alpine Lake Group Brettum index
Relative proportion of 2 highest indices
 modified Brettum index
EQR = modified Brettum index : ref.trophic value
where to set boundaries … under discussion
e.g. Austrian standard (ÖNORM M3260):
next trophic status class = moderate status
oligo … reference = High
oligo/meso … Good?
meso … Moderate?

13. Alpine GIG – Lakes Time table ALPINE GIG
Feb/Mar: submission of supplement data to ALPDAT
Apr/May: evaluation of ALPDAT
May/Jun: meeting in SI incl. Excursion