1. PHYTOPLANKTON IN THE WATER FRAMEWORK DIRECTIVE
Presented by Caridad de Hoyos
CEDEX (Spain)

2. Biological quality elements:
Atlantic GIG - phytoplankton and macrophytes
Alpine GIG - phytoplankton, macrophytes and benthic diatoms
Central/Baltic GIG – phytoplankton, macrophyte vegetation
Mediterranean GIG – phytoplankton
Northern GIG – phytoplankton for eutrophication, macroinvertebrates and fish for acidification

3. The most appropriate indicator for the pressure Eutrophication
BIOLOGICAL QUALITY ELEMENTS FOR THE CLASSIFICATION OF ECOLOGICAL STATUS:
PHYTOPLANKTON
The most appropriate indicator for the pressure Eutrophication
Abundance and Biomass
Composition
Abundance: number of cells or individuals per volume of water
It is a not good indicator due the differences between sizes in phytoplankton cells and individuals

4. Advantages Disadvantages Clorophyll a (g/l) Rapid method
BIOMASS
Advantages
Disadvantages
Clorophyll a
(g/l)
Rapid method
Indirect measurement
Biovolume
(mm3/l)
Direct measurement
It takes a lot of time
These parameters are interrelated. The relationship depends both on the groups of algae present and the growth state of the community
Period considered: grouwth season (May-Oct, Ap-Sep), August

5. COMPOSITION Advantages Disadvantages
Based on taxonomic groups of algae
Experts on Taxonomy not required
Criticized by some scientists (1)
Based on indicator species
It is considered to be better eutrophication indicator than those based on taxonomic groups of algae
More information is needed (2)
Experience of the investigator is required
(1) Some scientists say that most groups of algae (e.g. Cyanobacteria) have species along the whole trophic spectrum. So we should considered indicator species rather than groups.
(2) There are indices, based on species, made for Northern Europe. It is required a validation of these methods for the Mediterranean area.

6. Phytoplankton – common metrics
Northern GIG (Meeting )
For abundance and biomass: Chlorophyll-a and total biovolume
For taxonomic composition:
- Percentage Cyanobacteria to overall cell biomass
- relative abundance between chrysophytes and cyanobacteria
(based on biovolume)
Central GIG
For abundance and biomass: Chlorophyll-a
For taxonomic composition:
- Dominant taxa (based on biomass calculation or estimation)

7. Phytoplankton – common metrics
Alpine GIG (Meeting )
For abundance and biomass: Chlorophyll-a and total biovolume
For taxonomic composition:
- Relative proportions of algal classes (based on biovolume)
- French index (based on relative abundance)
-Relative proportion of dominant taxa (based on biovolume)
-Brettum index (based on biovolume)
Atlantic GIG (Meeting )
For abundance and biomass: Chlorophyll-a and total biovolume
For taxonomic composition:
- Percentage Cyanobacteria to overall cell biomass

8. SEDIMENTATION
An Utermöhl chamber must be used, which is composed by a bottom counting chamber and a chamber cylinder
The samples must be adapted to room temperature before they are set up for sedimentation.
Then, they have to be mixed up by turning the bottle upside-down approximately 100 times.
Sedimentation time depends on the volume of the subsample. For oligotrophic and mesotrophic waters it is common to use 50 ml chambers. In this case, the sedimentation time is 24 h.
Figures: bottom counting chamber and chamber cylinder set up for sedimentation

9. MICROSCOPICAL EXAMINATION OF SAMPLES
Quantitative analyses must be done under an inverted microscope with magnitudes of e.g. 100 x, 400x, and 1000 x.
One eyepiece should be equipped with a calibrated ocular micrometer.

10. Eutrophication Index based on phytoplankton composition
(Groups of algae )
Barbe et al, 2003
(based on the relative abundance of the groups)
IPL =  (Qi.Aj)
IPL – Plankton Index
Qi –
Aj – Relative abundance
Sampling with a net of 10 m mesh size
Simple microscope
Magnifications: 200 x – 600 x
Counting 100 individuals or colonies
Group of algae Qi
Desmids 1
Diatoms 3
Chrysophyta 5
Dinoflagellates and Cryptomonads 9
Chlorophyta (without Desmids) 12
Cyanobacteria 16
Euglenophyta 20
Relative abundance Aj
0 a < 10
10 a < 30 1
30 a < 50 2
50 a < 70 3
70 a < 90 4
90 a < 100 5

11. Eutrophication Index based on phytoplankton composition
(Groups of algae )
Catalán et al, 2003
(based on biovolumen)
Iga = 1+0,1Cr+Cc+2(Dc+Chc) + 3Vc +4Cia / 1+ 2(D+Cnc) + Chnc+Dnc
Iga – Group of algae composition index
Cr - Cryptomonads
Cc - Colonial Chrysophyte
Dc - Colonial Diatoms
Chc - Colonial Chlorococcales
Vc - Colonial Volvocales
Cia – Cyanobacteria
D - Dinoflagellates
Cnc -Chrysophyte not colonial
Chnc - Chlorococcales not colonial
Dnc - Diatoms not colonial

12. Eutrophication Index based on phytoplankton composition
(Indicator species )
Brettum, 1989
Hörnström, 1981
Heinonem, 1980
IT =  (v.Is)/  v
IT - Index for a certain trophic level
v - Species biovolume
Is - Trophic species Index for a certain trophic level
7 trophic levels
132 taxons
Biovolume of eutrophic species / Biovolume oligotrophic species
15 oligotrofic species
70 eutrofic species
IL=  (f.Is)/  f
IL - Trophic lake Index
f - Species frecuency
Is - Trophic species Index
72 taxons
nº individuals f 1
2-10 2
10-40 3
40-200 4
>200 5

13. Phytoplancton questionnaire Answers
Totally 4 countries
Partially 1 country
Phytoplankton biovolume and/or phytoplankton composition are useful as phytoplankton quality elements to be used for setting intercalibrated class boundary values. YES-4
For phytoplankton studies, Utermöl method is the most reliable method to be used (See Guidance standard for the routine analysis of phytoplankton abundance and composition using inverted microscopy , Utermöhl technique: CEN TC 230/WG 2/TG 3/N83). YES-3. NOT COMMENT-1
Number of cells or individuals per volume of water is not a good indicator due to the differences between sizes in phytoplankton cells and individuals (See second slide of the presentation about phytoplankton shown at the meeting held on 16th December, last year). YES-4
The best way to express quantitatively a group (or taxa) of algae or total phytoplankton is biovolume. YES-4
Question 1: Do you have at your disposal an inverted microscope and Utermöhl chambers to apply the Utermöhl technique?. YES-2. NOT-1. NOT EVERYWHERE IN THE COUNTRY-1
Question 2: Do you have phytoplankton results expressed as biovolume or are you able to get data on this parameter? (See the document “Analysis of phytoplankton” sent to you at ). YES-3. NOT-1. NOT EVERWHERE IN THE COUNTRY-1
Question 3: Could you have on September 2005 biovolume results for all groups of phytoplankton (Cyanobacteria, Diatoms, Dinoflagellate, etc.)? YES-2 NOT FOR SURE-3
Question 4: Could you have on September biovolume results for Cyanobacteria? YES-2. NOT FOR SURE-3

14. Swedish lakes (Willén, 2000)
Deep lakes:
Biovolume(May-Oct) = 0,05 TP(May-Oct) – 0,2
Shallow lakes (<3m):
Biovolume(May-Oct) = 0,055 TP(May-Oct) + 0,132
The changing proportion of algal classes, as a function of increased phosphorus concentrations and increasing biomasses of planktic algae, is illustrated in the figure. The successive increase of cyanobacteria and the evident decrease of chrysophytes are the most conspicuous features

15. Phytoplankton from different German ecoregions
German lakes (Nixdorf et al, 2001)
Phytoplankton from different German ecoregions
Lowland lakes have higher natural trophic potencial than lakes in Alps and prealps.
The higher trophic state of lowland lakes is also documented by the increasing portion of Cyanobacteria on the total phytoplankton biomass.

16. Spanish reservoir (de Hoyos et al, 2004)
Under conditions of the same amount of total phosphorus, cyanobacteria growth is higher in the western area. We think this is due to the lower N/P ratio found in this area

17. German lakes (Nixdorf et al, 2001)
Tested the Hornström index for a data set of lowland lakes in Germany, it was found applicable.
There are four lakes in the graph with high biomass but low lake index.
This results show that it is necessary to adapt the single species importance for the study area