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

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

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

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

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.

Phytoplankton – common metrics Northern GIG (Meeting 17-9-04) 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)

Phytoplankton – common metrics Alpine GIG (Meeting 25-1-05) 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 22-9-04) For abundance and biomass: Chlorophyll-a and total biovolume For taxonomic composition: - Percentage Cyanobacteria to overall cell biomass

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

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.

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

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

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

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 26-11-2004). 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 2005 biovolume results for Cyanobacteria? YES-2. NOT FOR SURE-3

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

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.

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

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