VESIENTUTKIMUSLAITOKSEN JULKAISUJA PUBLICATIONS OF THE WATER RESEARCH INSTITUTE PERTTI HEINONEN QUANTITY AND COMPOSITION OF PHYTOPLANKTON IN FINNISH INLAND WATERS TivisteImä Suomen sisävesien kasviplanktonin määristä ja koostumuksesta VESIHALLITUS—NATIONAL BOARD OF WATERS, FINLAND Helsinki 1980 Tekijä on vastuussa julkaisun sisällöstä, eikä siihen voida vedota vesihallituksen virallisena kannanottona. The author is responsible for the contents of the publication. It may not be referred to as the official view or policy of the National Board of Waters. ISBN 951-46-4612-6 ISSN 0355-0982 HeIsink 1980. Valtion painatuskeskus 3 CONTENTS 1. Introduction 5 2. Aims of the research 6 3. Materiais and methods 7 3.1 Sampling 7 3.2 Microscopical examination of sampies and the treatment of the results 7 4. Results 8 4.01 Regional division 8 4.02 Small river basins draining into Lake Ladoga 8 4.03 The Vuoksi river basin 9 4.031 Watercourses east of Lake Haukivesi 9 4.032 Watercourses north of Lake Haukivesi 13 4.033 Lake Haukivesi and watercourses to the south of it 16 4.04 The Kymijoki river basin 18 4.041 Watercourses north of the rapid of Haapakoski 18 4.042 Lake Päijänne and watercourses draining into it 20 4.043 Watercourses south of the Kalkkinen canal 20 4.05 River basins to the south of Salpausselkä 23 4.06 River basins of southwest Finland 24 4.07 The Kokemäenjoki river basin 24 4.071 Watercourses north of Lake Pyhäjärvi 24 4.072 Lake Pyhäjärvi and watercourses to the east of it 27 4.073 Watercourses below the River Nokianvirta 29 4.08 River basins of Ostrobothnia 29 4.09 The Oulujoki, lijoki, Kuivajoki and Simojoki river basins 32 4.10 The Kemijoki and Tornionjoki river basins 32 4.11 River basins of northern Lapland and Kuusamo 35 5. Discussion 35 5.1 Regional survey of phytoplankton biomasses 35 5.2 Total phytoplankton biomass leveis 35 5.3 Phytoplankton composition 39 5.31 Divisions and orders 39 5.32 Number of species 42 5.33 Diversity 43 5.4 Quotients 43 5.41 ElO and EVIOV quotients by Järnefelt 43 5.42 The species quotients by Thunmark and Nygaard 46 5.43 Odourindex 48 5.5 Occurrence of species 49 5.51 Qualitative analysis 49 5.52 Quantitative analysis 49 5.53 Indicator species 52 5.531 Indicators used by Järnefelt 52 5.532 New indicator species 54 4 6. Summary 54 7. Acknowledgements 56 Lopputiivistelmä 56 References 57 Appendices 62 5 QUANTITY AND COMPOSITION OF PHYTOPLANK TON IN FINNISH INLAND WATERS Pertti Heinonen Heinonen, P. 1980. Quantity and composition of phytoplankton in Finnish inland waters. Publications of the Water Research lnstitute, National Board ofWaters, Finland, No. 37. A regional survey of the quantity and composition of phytoplankton in Finnish inland waters was carried out on the basis of 826 sampies taken iii the midsummer of 1963 and 1965. On the basis of this investigation and of other data collected for lakes studied, a scale of eutrophication was drawn up according to midsummer phytoplankton leveis. Lakes, in which the phyto plankton biomass (fresh weight) was below 0.2 mg/l, were classified as ultra oligotrophic, while leveis of 0.21—0.50 mg/l were designated oligotrophic. Quantities of biomass between 0.51 and 1.00 mgJl indicated incipient eutrophy, 1.01—2.5 mg/1 mesotrophy, 2.51—10.0 mg/l eutrophy and over 10.0 mg/l hypereutrophy. The dominating species were Centrales diatoms. With increasing eutrophication the amounts of Hormogonales blue-green algae and of PntococcaJes green aigae increased most markedly. A tota] of 680 taxons were identified from the samples. Species number increased with increasing biomass at least to biomass values of 5 mg/1. The usability of different quotients was examined and a new variable, the odour mdcx, was developed. The odour mdcx was very significantly correlated with biomass. On the basis of the research material 21 new indicator species of eutrophica tion and 10 of oligotrophy were proposed. mdcx words; Eutrophication, phytoplankton, water quality, quotiencs, diversity, indicator species, odour mdcx. 1. INTRODUCTION Evaluation of water quality in watercourses is investigations is the detection of the often very carried out almost entirely on the basis of slow changes taking place in water quality. The information concerning the biotope gained from natural ageing of water is in many areas consider physical and chemical analyses. This information ably accelerated by human activity in the form naturally inciudes various changes brought about of e.g. regulation of lakes, reduction in water by the action of biological processes. Direct leveis, construction activity in the vicinity of measurements of the intensity of such processes watercourses and, in particular, the discharge or of the quantity and quality of the different of effluents. The effects of these activities are factors describing biocoenosis are only rarely often observed later as increased nutrient con used in routine investigations of water quality. centrations, leading eventually to corresponding One of the main problems of watercourse increases in primary production. Eutrophication 6 is without doubt at present one of the most (Strickland & Parsons 1965, Tolstoy 1966, 1977 difficult processes to control in large watercourse and 1979). This is a rapid method, but has the systerns. drawback that the result obtained is dependent Several different methods can be employed on the species composition and growth phase for the monitoring of eutrophication. If the of the plankton (Viljamaa et al. 1978). growth-limiting nutrient (e.g. phosphorus) for a Investigation of phytoplankton by direct given watercourse is known with certainty, it is microscopy yields information concerning specles possible to estimate resultant leveis of phyto composition in addition to total counts. This plankton biomass solely on the basis of assays of information has for Iong been used in studies this nutrient (Sakamoto 1966). The advantages comparing different lakes. Different parameters of this method are ease of performance and and indicator species and groups have been used precision of analysis, while the major restriction as a means of following changes in, rather than arises from variations in the significance of merely classifying, water quality. The quotient different factors for primary production between systems of Thunmark (1945) and Nygaard(1949) different watercourses and different times. are based on comparison of species frequencies Measurements of the intensity of primary of phytoplankton groups, whereas that of Järne 14C-method (Steemann felt (1952b and 1956a) and Järnefelt et al. production by the Nielsen 1952) have also been used to estimate (1963) is based on the relationships between the eutrophication. This method has the same species numbers and volumes of phytoplankton advantage as the preceding: complex biological species considered to be useful as indicators. The processes are estimated on the basis of simple applicability of quotients is generally considered physical and chemical procedures. A weakness to be restricted to rather precisely defined is that the obtained resuit is difficult to utilize geographical areas (Rawson 1956). e.g. in the estimation of water usability. The The estimation of phytoplankton biomass by 14C-method also contains several uncertainties microscopy is associated with several uncertainty of operation and gives only proportional results. factors arising from e.g. sampling, counting and One of the oldest biological water research species identification (Preston 1948, Kutkuhn 1975, methods is the examination of the biomass and 1958, van Heusden 1972, Hobro & Wi1ln composition of phytoplankton by microscopy. Kaatra & Harjula 1976, Hallegraeff 1977). The first investigations carried out in Finland However, this is the only method yielding were mainly qua[itative analyses of sampies qualitative information concerning the species collected from the photic water layer using composition of phytoplankton in addition to nets of different mesh size (Levander 1900, quantitative estimates of total biomass. Such Levander & Wuorentaus 1915 and 1917, Järnefelt qualitative information is often of considerable 1925), although the need for a quantitative significance in the monitoring of water quality in method had for long been appreciated (Järnefelt watercourses (Järnefelt 195 2b, Findenegg 1958, 1929 and 1930). Only since the development of Kostiainen 1965, Seppänen 1969). techniques for analysing sedimented water sampies without further treatment, and of the Utermöhl technique, has quantitative exam 2. AIMS OF THE RESEARCH ination of phytoplankton been possible (Uter möhl 1931 and 1958, Järnefelt 1934, 1936a The first extensive water sampling programme and b). The inclusion of algal species volumes to by the water protection authorities, with the indicator systems (Järnefelt 1952a) has consider aim of examining the water quality of water ably improved possibilities for realistic com courses on a regional basis using a biological parison between different lakes. method, took place in summer 1963, when In addition to counting by direct microscopy, a total of 328 phytoplankton sampies were estimations of total phytoplankton have been collected from different areas. This investiga carried out by chemical means on the basis of tion, covering the whole country, was repeated the concentration of photoenergetic pigments in the summer of 1965, when sampies were 7 taken from 498 sampling stations. The micro Sampies were taken mainly as profile sampies scopic examination of ali 826 sampies was from the epilimnion, the depth of which was completed by the end of 1970. first determined on the basis of temperature The aim of the present research was to use the measurements. In the case of stations situated by data obtained from the above examinations shaliow, weilmixed water sampies were taken — to determine the quantity and composition of from a depth of one metre with a Ruttner-type phytoplankton in midsummer in different water sampier. Sampling depths are given with iakes, the results from individual observation sites — to estimate the significance of parameters (Appendix 1).