Oceanological and Hydrobiological Studies. International Journal of Oceanography and Hydrobiology. Vol. XXXIII, No.3 (31-46) 2004

Transcription

1 Oceanological and Hydrobiological Studies International Journal of Oceanography and Hydrobiology Vol. XXXIII, No.3 Institute of Oceanography ISSN X (31-46) 2004 University of Gdańsk eissn Original research paper Applicability of diatom indices for monitoring water quality in coastal streams in the Gulf of Gdansk Region, northern Poland 1 Aleksandra Zgrundo 2, Bożena Bogaczewicz-Adamczak Institute of Oceanography, University of Gdańsk Al. Piłsudskiego 46, Gdynia, Poland Key words: diatoms, indices, water pollution, coastal zone, Gulf of Gdańsk Abstract This aim of this study was to test the applicability of diatom indices developed in Europe for monitoring coastal stream waters in northern Poland. Water, sediment, and diatom samples were taken from streams in the resort town of Sopot that discharge into the Gulf of Gdańsk. The physical and chemical measurements taken during the sampling period indicated that the purity of the stream waters had improved, and recently they were classified as I class water purity. This is contrasted by the studied waters diatom communities, which were dominated by eutraphentic taxa. High abundances of β-mesosaprobic and α-mesosaprobic taxa were recorded at most of the sites. Diatom indices developed for water quality surveillance were calculated with the Omnidia 3 database software. Redundancy analyses (RDA), an ordination technique, was used to determine the indices that best correspond to water pollution in coastal streams. 1 Results of this paper were presented on an 5 th International Symposium Use of Algae for Monitoring Rivers Cracow, 2-6 September 2003, Poland. 2 aleks@sat.ocean.univ.gda.pl

2 32 A. Zgrundo, B. Bogaczewicz-Adamczak The results of the present study indicate that the pollution indices that follow can be applied successfully to monitor flowing freshwaters in the Gulf of Gdańsk area in northern Poland: IDAP (Indice Diatomique Artois-Picardie); SPI (Specific Polluosensivity Index); EPI-D (Eutrophication/Pollution Index based on Diatoms), which integrates organic pollution, eutrophication, and mineralization. INTRODUCTION The sensitivity of diatoms to water pollution and their application in monitoring environmental degradation has a long history and is well established (e.g., Descy 1979, Lange-Bertalot 1979, Sládeček 1986, Hofmann 1994, Kelly et al. 1996, Prygiel and Coste 1996, Stachura and Witkowski 1997, Eloranta 1999, Prygiel et al. 1999). In recent years, diatom indices have been developed that characterize with a numerical value the ecological status of waters. About twenty different methods using benthic diatoms are applied in Europe (Prygiel et al. 1999). However, they are known to be particular to specific geographic regions and none of them is appropriate for evaluating water pollution in other parts of the world with repeatable accuracy. For example, the DAIPO index developed by Watanabe (1986) in Japan does not seem to be useful in European waters. Others, such as the SPI, CEC, and DES, produce the best results in Finland, while the SPI, CEC, and the GDI do so in France, and the SPI, GDI, and TDI seem to work best in England and Scotland (Prygiel et al. 1999). Kawecka et al. (1999) and Kwandrans et al. (1999) found that SPI and GDI are the most reliable for monitoring rivers in southern Poland. This study presents results of testing indices calculated using Omnidia software and their potential for monitoring coastal stream waters in the area of Sopot, a resort located on the coast of the Gulf of Gdańsk in the Baltic Sea. Relationships between diatom indices and environmental variables were established and discussed based on ordination analysis. MATERIALS AND METHODS Water, sediment, and diatom samples for analyses were taken simultaneously in four streams that discharge into the Gulf of Gdańsk in the Sopot resort between March 1999 and February The material studied was sampled and measurements were performed at fourteen sites situated along the course of the Haffnera, Babidolski, Grodowy and Swelinia streams and in their mouths (Fig. 1). All of the streams, except for Swelinia, are situated in residential areas of the Sopot resort. Their waters flow through the urban area in underground cement canals ranging in length from m and in a series of open canal

3 Applicability of diatom indices for monitoring water quality 33 Fig. 1. Location of sampling sites within the coastal zone of the Gulf of Gdansk. Inset shows location of the study area within the Baltic Sea. segments from 100 to 450 m long. Inflows of rainwaters and illegal sewage systems are potential sources of pollution in these streams. Swelinia Stream is the longest at 3500 m, and it has a hydrobotanic sewage treatment plant. Swelinia is the only stream flowing in a natural, unregulated bed. The stream flows through the Tri-City (Gdańsk, Sopot, Gdynia) Landscape Park, a residential area and, in its lower course, through a deep, forested ravine. This is the only stream along the Gulf of Gdańsk coast with a natural mouth. Potential pollution sources for the stream are outflows from allotments, rest centers and a housing estate. Some water parameters including temperature, salinity, ph, conductivity, redox potential, and oxygen content were measured with a WTW MultiLine F/SET-3 probe. Water samples for nutrient concentration analyses (PO 4 -P, NO 2 - N, NO 3 -N and NH 4 -N) and sediment samples for measuring organic matter content were deep-frozen after sampling and analysed using standard methods (Trzosińska et al. 1980). Diatom samples were collected from the substrata prevailing at a particular site, mainly from stones and concrete bedding. Only at stations S2 and S5 were samples collected from a sandy bottom. Samples for diatom analysis were treated initially with 10% HCl, then washed with distilled water and boiled with 30% hydrogen peroxide in a water bath for three days at temperatures between 60 C and 90 C. Finally, each sample was washed several times with distilled

4 34 A. Zgrundo, B. Bogaczewicz-Adamczak water. Permanent diatom preparations were mounted in Naphrax. Diatom analyses were performed under a light microscope at a magnification of Approximately 550 diatom valves were counted in each slide. The diatoms were identified according to Krammer and Lange-Bertalot (1986, 1988, 1991a, 1991b), Snoeijs (1993), Snoeijs and Vilbaste (1994), Snoeijs and Potapava (1995), Snoijes and Kasperovičiene (1996), and Witkowski et al. (2000). The frequency of dominant diatoms in the studied samples was calculated according to the proposal of Tischler (Trojan 1975). The ecological grouping of taxa, including salinity, trophy, and saprobic conditions, was based on Krammer and Lange-Bertalot (1986, 1988, 1991a, 1991b), Pankow (1990), Denys (1991/92), Snoeijs (1993), Hofmann (1994), Snoeijs and Vilbaste (1994), Van Dam et al. (1994), Snoeijs and Potapava (1995), Snoijes and Kasperovičiene (1996), and Witkowski et al. (2000). The Omnidia 3 (Lecointe et al. 1993) diatom database software was used to calculate the indices developed by various authors, as follows: CEC (Diatom Index by Descy and Coste, 1991); DES (Descy s index, 1979); EPI-D (Eutrophication/Pollution Index based on Diatoms by Dell Uomo, 1996); GDI (Genus Diatom Index by Coste & Ayphassorho, 1991); IDAP (Indice Diatomique Artois-Picardie, Prygiel et al. 1996); LMI (Leclercq and Maquet s index, 1987); SHE (Schiefele and Schreiner s index, 1991); SLA (Sládeček s index, 1986); SPI (Specific Polluosensivity Index by Coste in Cemagref, 1982); TDI (Trophic Diatom Index by Kelly & Whitton, 1995). Diatom indices can be divided into four groups according to their objective: 1. saprobic indices based on the Zelinka and Marvan formula, e.g., SLA, LMI; 2. trophic indices for evaluating nutrient levels in watercourses, e.g., TDI; 3. pollution indices based on the sensitivity and amplitude of diatoms towards pollution considered as a simple factor, e.g., DES, SPI, GDI, CEC, IDAP; 4. indices combining organic pollution, eutrophication, and mineralization, e.g., EPI-D (Prygiel et al. 1999). Numerical analysis was performed with the statistical program Canoco version 4.5 (ter Braak and Šmilauer 2002). DCA ordination analysis was applied first to prove the linear response of diatom indices. It was shown that linear methods (PCA, RDA) are preferable with the current dataset since the length of the gradient for the first axis was short at SD (Lepš and Šmilauer 1999). RDA was applied to check variation in diatom indices that can be explained by a particular set of environmental variables. This is a direct gradient analysis based on the linear responses of internal variables, and it is very effective if the relevant environmental data are available. One of the

5 Applicability of diatom indices for monitoring water quality 35 attractive features of redundancy analysis is that it leads to an ordination diagram that displays simultaneously the main pattern of diatom index variation, as far as this variation can be explained by environmental variables, and the main pattern in the correlation coefficients between the indices and each of the environmental variables (ter Braak and Prentice 1988). Of the 262 samples, 242 containing a sufficient amount of environmental data were included in the numerical analysis. The diatom indices were centered and standardized to produce analyses based on the matrix of correlation coefficients. The significance of the RDA axes was assessed using the Monte Carlo permutation test with 499 random permutations. RESULTS Chemical Analyses The measured values (mean, minimum, and maximum) of the water chemistry variables are presented in Tables 1 and 2. The values of some parameters such as ph, conductivity, redox potential, dissolved oxygen, nitrate (NO 3 ) and ammonium (NH 4 ) showed increases downstream, but these were relatively low and characteristic for clean and slightly polluted waters. Higher salinity values were noted at all stations except Swelinia Stream. Salinity of up to 0.4 PSU was noted in the winter at the stations in the Haffnera, Babidolski Table 1 Some average, minimum and maximum values for the water quality variables in the stream stations. Stream salinity ph conductivity redox diss. oxygen [μs cm -1 ] [mv] [mg l -1 ] Haffnera 0.01 ( ) 8.05 ( ) 516 ( ) -59 ( ) ( ) Babidolski 0.01 ( ) 7.93 ( ) 534 ( ) -53 ( ) 10,55 ( ) Grodowy 0.01 ( ) 7.80 ( ) 508 ( ) -55 ( ) ( ) Swelinia ( ) 408 ( ) -63 ( ) ( ) Table 2 Some average, minimum and maximum values for the water quality variables in the mouth stations. Stream org.mat. [% dw] PO 4 -P [μm dm -3 ] NO 2 -N [μm dm -3 ] NO 3 -N [μm dm -3 ] NH 4 -N [μm dm -3 ] Haffnera 1.61 ( ) 1.96 ( ) 0.57 ( ) ( ) 0.50 ( ) Babidolski 1.42 ( ) 1.13 ( ) 0.52 ( ) ( ) 3.90 ( ) Grodowy 1.31 ( ) 1.26 ( ) 0.28 ( ) ( ) 0.50 ( ) Swelinia 0.87 ( ) 1.29 ( ) 0.35 ( ) ( ) 0.17 ( )

6 36 A. Zgrundo, B. Bogaczewicz-Adamczak and Grodowy streams. At the mouth stations the salinity increased sporadically up to 2.4 PSU. High nitrite (NO 2 ) concentrations of up to 1.18 μmol dm -3 were noted mostly during spring and summer 1999 at the mouth stations of the Babidolski, Grodowy and Haffnera streams. Similarly high phosphate (PO 4 ) concentrations of up to 7.48 μmol dm -3 were noted at mouth stations but only in the spring months in Generally, the water quality in the streams improved during the sampling period and for the second and third year of the study all of the measured variables were typical of I class, and sporadically II class, water purity. Diatom Flora Altogether 417 diatom taxa were identified (126 solely in streams and 94 in the mouth sites) in the material studied. Table 3 presents the dominant species together with their frequency and autecology. In both the stream and mouth sites Achnanthidium minutissimum, Amphora pediculus, Eolimna minima, Gomphonema parvulum, Navicula gregaria, Nitzschia dissipata var. dissipata, Nitzschia inconspicua, and Planothidium lanceolatum reached the highest abundance and were absolutely constant in the diatom assemblages. Staurosira elliptica was the only dominant species identified solely in the stream sites. On the other hand, diatoms recorded only in the mouth sites were Fragilaria gedanensis, Martyana atomus, and Mayamaea atomus. According to the Van Dam et al. (1994) salinity classification, most of the sites were dominated by fresh-brackish water diatoms with, among others, the following constants: Achnanthidium minutissimum; Amphora pediculus; Gomphonema olivaceum; Navicula cryptotenella; N. Lanceolata; Nitzschia dissipata; N. inconspicua. Only at the mouth sites did abundances of brackishfresh and brackish taxa (e.g., Fragilaria gedanensis, Martyana atomus, Navicula gregaria, N. perminuta, Nitzschia frustulum) seasonally exceeded those of fresh-brackish ones. With respect to trophic conditions, the diatom assemblages at all stations were dominated by eutraphentic species. Hypereutraphentic taxa such as Mayamaea atomus, Nitzschia liebetruthii, and N. palea were also recorded quite frequently. With regard to the saprobic spectrum in the material studied, mesosaprobic taxa dominated with the prevalence either of β-mesosaprobic or of α-mesosaprobic, depending on the stream studied. The diatom assemblages had a high frequency of α-polisaprobous and polisaprobous species, e.g., Eolimna minima, Luticola mutica, Mayamaea atomus, Nitzschia palea and Planothidium frequentissimum. Diatom analyses revealed that the waters in the mouths were more polluted with the organic compounds of the affluents studied than were the upstream sections of the watercourses.

7 Applicability of diatom indices for monitoring water quality 37 Table 3 Dominant diatom taxa recorded from streams with their frequency and autecology. (frequency: %, %, %, %; salinity: f freshwater <0.8 PSU, f-b fresh-brackish PSU, b brackish-freshwater and brackish PSU; trophic state: O oligotraphentic, M mesoeutraphentic, E eutraphentic, H hypereutraphentic; saprobity: o oligosaprobous, β - β-mesosaprobous, α - α-mesosaprobous, p polisaprobous) Diatom taxon frequency stream mouth salinity trophy saprob. Achnanthidium minutissmium (Kützing) Czarnecki 4 4 f-b O-E β Ampohora ovalis Kützing 1 1 f-b E β Amphora pediculus (Kützing) Grunow 4 4 f-b E β Cocconeis pediculus Ehrenberg 2 2 f-b E β Denticula tenuis Kützing 2 2 f M o Diadesmis contenta (Grunow) Mann 1 1 f O-E β Diatoma moniliformis Kützing 2 2 f E β Eolimna minima (Grunow) Lange-Bertalot 4 4 f E α/p Fragilaria capucina var. gracilis (Østrup) Hustedt 2 2 f-b O-M o Fragilaria gedanensis Witkowski 0 2 b * * Fragilaria martyi (Heribaud) Lange-Bertalot 1 1 f M-E o Gomphonema olivaceum (Hornemann) Brébisson 3 4 f-b E β Gomphonema parvulum Kützing 4 4 f E α/p Luticola mutica (Kützing) Mann 2 2 f-b E α Martyana atomus (Hustedt) Snoeijs 0 2 b E * Mayamaea atomus (Kützing) Lange-Bertalot 0 2 f H α/p Mayamaea atomus var. permitis (Hustedt) Lange-Bertalot 0 2 f-b E α/p Navicula bozenae Lange-Bertalot, Witkowski & Zgrundo 1 2 * * * Navicula cryptotenella Lange-Bertalot 3 4 f-b O-E β Navicula gregaria Donkin 4 4 b E α Navicula joubaudii Germain 3 3 f-b * β Navicula lanceolata (Agardh) Ehrenberg 3 4 f-b E α Navicula perminuta Grunow 1 2 b * β Navicula tripunctata (O.F. Müller) Bory 3 3 f-b E β Nitzschia dissipata var. dissipata (Kützing) Grunow 4 4 f-b M/E β Nitzschia frustulum (Kützing) Grunow 3 3 b E β Nitzschia inconspicua Grunow 4 4 f-b E α Nitzschia liebetruthii Rabenhorst 1 2 f-b H β Nitzschia palea (Kützing) W.M. Smith 3 2 f-b H p Planothidium frequentissimum (Lange-Bertalot & Krammer) Round & Bukhtiyarova 3 3 f-b O-E α/p Planothidium lanceolatum (Brébisson) Round & Bukhtiyarova 4 4 f E α Staurosira elliptica (Schumann) Williams & Round 1 0 f-b M-E β Surirella brebissonii Krammer & Lange-Bertalot 2 2 f-b E α

8 38 A. Zgrundo, B. Bogaczewicz-Adamczak Statistical Analysis The diatom indices and environmental variables were analysed using constrained ordination RDA. Firstly, RDA was performed for each index and the environmental data separately. This indicated that the best indices for describing water quality in the current data set were EPI-D, IDAP, and SPI since the length of the gradients were 0.221, 0.220, and 0.216, respectively. Following this, RDA for EPI-D, IDAP, SPI, and environmental data was performed. The eigenvalues for RDA axes 1 and 2 (Fig. 2) were and 0.012, respectively, and were both significant (p<0.05, Monte Carlo test with 499 unrestricted permutations). They explained 22% of the total variance in the data of this index. The indices-environment correlations for RDA axes 1 and 2 were 0.49 and 0.33, respectively. The first axis explained 92.7% and the second 97.9% of the total variance in the index-environment relation. The correlation matrix indicated that the distance of the station from the source and nitrate concentrations made the most significant contribution to axis 1, while ph and salinity did so to axis 2. According to the coefficients and biplot scores of the Fig. 2. The RDA ordination plot of diatom indices, environmental variables and sites. The symbols for sites are: empty star source site, empty circle middle course site, empty square mouth site

9 Applicability of diatom indices for monitoring water quality 39 environmental variables, diatom indices were most strongly affected by site distance, and this variable explained 15% of the total variability in index variation. The next most significant variables were nitrite and nitrate with scores of 6% and 4%. The EPI-D index was mostly affected by nitrites, whereas IDAP and SPI were affected by nitrate concentrations, together with organic matter, phosphates, and conductivity. The influence of salinity on the studied indices was so small that it can be disregarded. The results of ordination analysis showed that each variable has a unique influence on diatom index gradients. The variance inflation factor (VIF) was calculated for this purpose (ter Braak and Šmilauer 2002). The lower the VIF value, the more unique the influence particular environmental variables have on index distribution. The VIF values for all the analysed variables were much lower than 20 suggesting that none of them is correlated with the others. In the RDA diagram the sites are indicated by points while both diatom indices and environmental variables are indicated by arrows (Fig. 2). The arrows that are pointing in roughly the same direction indicate a high positive correlation. Arrows that cross at right angles indicate a near-zero correlation, whereas those pointing in opposite directions indicate a high negative correlation (Ter Braak and Prentice 1988). Furthermore, environmental variables with long arrows are the most important in the analysis; the longer the arrow, the more confident one can be about the inferred correlation. The lengths of arrows of the environmental variables are comparable since they have been standardized to zero mean and unit variance (l.c.). The distribution pattern of environmental variables in the current dataset shows a strong positive relation among nutrient concentration, organic matter content, and conductivity. These variables, especially nitrates, are strongly negatively correlated with distance from the sources. Similarly strong negative correlations were obtained for salinity, temperature, and dissolved oxygen on the one hand, and redox, ph, and ammonium on the other. Ordination clearly separated sites into clusters depending on the distance from the sources. The sites were grouped into three categories: source, middle course and mouth. As illustrated in the plot, source sites were characterized by the strongest possible impact of nitrites and nitrates, whereas the middle course by temperature and dissolved oxygen, and the mouth sites by reversed nutrient concentrations. By perpendicularly projecting the sample points onto an arrow of an index, the approximate ordering of the samples in the order of increasing value of that index is given. A projection point near the zero point (the coordinate system origin) corresponds to an average value of that particular index in that sample (Lepš and Šmilauer 1999). On this basis, it can be concluded that the highest index values that are tantamount to the highest water quality were recorded for

10 40 A. Zgrundo, B. Bogaczewicz-Adamczak the source sites and average for the middle course sites irrespective of the diatom index applied - EPI-D, IDAP or SPI. The correlations of the analyzed indices with mouth sites were mostly negative. DISCUSSION The results of the chemical analyses of water quality variables improved during the study period and ultimately the streams were characterized as unpolluted. However, the analysis of the ecological preferences of the diatom species revealed that the stream waters were eutrophic and polluted with organic matter. Similar discrepancies in the evaluation of water quality based on chemical parameters and diatom analysis have also been reported in other studies performed in the Gulf of Gdańsk region (Bogaczewicz-Adamczak and Koźlarska 1999, Bogaczewicz-Adamczak et al. 2001, Zgrundo and Bogaczewicz-Adamczak 2002). Diatom flora was dominated mainly by cosmopolitan species as Achnanthidium minutissimum, Amphora pediculus, Eolimna minima, Gomphonema parvulum, Nitzschia dissipata var. dissipata, Nitzschia inconspicua, and Planothidium lanceolatum (Krammer and Lange-Bertalot 1986, 1991a, 1991b), all of which were also recorded in flowing waters in other parts of Poland (Wojtal et al. 1999, Kwandrans 2000, Rakowska 2001). Based on RDA ordination analyses, it was determined that the best diatom indices in the studied area are the EPI-D index, which incorporates organic pollution, eutrophication, and mineralization, and the two IDAP and SPI pollution indices. The length of the gradient for the EPI-D, IDAP, and SPI indices demonstrated their potential for describing environmental quality in the data set studied. The EPI-D index was designed based on investigations of eight measurement stations on the River Chienti (Central Apennines) using the abundances of 93 diatom species (Dell Uomo 1996). The fact that EPI-D achieved the highest RDA analysis score suggests that diatom assemblages in the River Chienti and in the coastal streams of the Gulf of Gdańsk region are to a great extent similar. The high score for the IDAP index also indicates that the diatom assemblages are similar in the studied waters and the Artois-Picardie basin, upon which this index was developed based on 45 genera and 91 species (Prygiel et al. 1996). Although both the IDAP and SPI indices, which are the best pollution indices for describing water quality in the analysed dataset, showed a significant relation to nutrient concentrations, organic matter contents, and conductivity, the latter appears to have more potential mainly due to its construction and characteristics. The SPI index has been consistently updated and indicative values have recently been included for more than 2500 taxa (Prygiel et al. 1999).

11 Applicability of diatom indices for monitoring water quality 41 The IDAP and SPI were also found to be the best pollution indices in a previous study performed by Zgrundo and Bogaczewicz-Adamczak (2002) on the coastal streams of the Gulf of Gdańsk region. The SPI index was one of the indices recommended for monitoring rivers in Poland by Kawecka et al. (1999) and Kwandrans et al. (1999). Other studies, such as Prygiel et al and Ács et al. 2003, have confirmed that this index best matches the water quality in European countries. The eigenvalue of an ordination axis is used to show how much variance is accounted for by a particular axis. The higher the value, the more important the ordination axis is. Although the eigenvalues for the first two axes were low, the ordination performed was stable according the general rule of when s dimensions are used for ordination, it is unstable if the (s+1)th eigenvalue is close to the sth eigenvalue (Ter Braak 1994). RDA demonstrated that there was a distinct relationship between the indices calculated on the basis of diatom analysis and environmental variables. The proportion of variation in the diatom indices (22%) explained by the first two axes was higher than that indicated by Lepš and Šmilauer However, as pointed out by Ter Braak (1986), even an ordination diagram that explains only a low percentage can be quite informative. In the current case, variability explained by the submitted environmental variables resulted in biplots with a well-interpretable structure. The diatom indices-environment correlations for the first two RDA axes were low possibly due to the omission of significant environmental variables in the analysis. Most of diatom indices applied are related to organic pollution and, as stated in previous studies (e.g., Prygiel et al. 1999), are correlated significantly with BOD and COD, among other factors, which were not present in the current data set. The distance from sources, nitrites, and nitrates concentrations made the strongest contribution to the diatom indices distribution in the current data set; EPI-D was mostly affected by nitrites whereas IDAP and SPI - by nitrates. The latter were also slightly affected by phosphates, organic matter content, and conductivity. Such relations are in agreement with the general objectives of diatom-based indices. The distribution of environmental variables in RDA diagrams showed a negative correlation between temperature and dissolved oxygen and a significant relationship between temperature and conductivity, which are consistent with general interdependencies among the parameters above (Korzeniewski 1990). Similarly, some variables such as nutrients, especially nitrates, organic matter content, and conductivity were negatively correlated with distance from sources and confirm the general characteristics of flowing

12 42 A. Zgrundo, B. Bogaczewicz-Adamczak waters that indicate a downstream increase in nutrient and ion loads (Dojlido 1987, Wróbel 1988). The results of classifications based on physical and chemical measurements and the trophic and saprobic diatom spectrum indicated that the waters deteriorated downstream. The positive indices-source sites correlations and negative indices-mouth sites indicate an identical relation relevant to decreasing water purity. Based on the analyses performed, the EPI-D, IDAP, and SPI indices are the best for describing water quality in this dataset. They appear to be useful for waters with low nutrient concentrations and even at higher salinity levels, such as those in the studied mouth waters. Notwithstanding, the application of diatom indices in monitoring mouth waters can result in errors in water classification since diatom indices were developed for freshwater surveillance (Prygiel et al. 1999). CONCLUSIONS The redundancy analysis technique which was used to analyze and visualize the relationships between diatom indices and selected environmental variables in the streams discharging into the Gulf of Gdańsk coastal zone demonstrated that: the EPI-D, IDAP, and SPI indices produce the best results when evaluating the environmental quality of coastal streams; site distance from the sources, nitrites, and nitrates concentrations had the highest explanatory power to elucidate patterns in the indices data; source sites were characterized by higher water quality than mouth sites; the EPI-D, IDAP, and SPI indices can probably be successfully applied to monitor waters with low nutrient concentrations; diatom indices can produce correct results in waters of higher salinity level. ACKNOWLEDGEMENTS The authors extend their special thanks to Professor Horst Lange-Bertalot and Professor Andrzej Witkowski for their help in identifying species. The authors would also like to thank Dr. Bożena Graca and Katarzyna Walenciej for water and sediment analyses and Dr. Gavin Simpson for help with the statistical analysis. The study was supported by a grant from the State Committee for Scientific Research KBN 6PO4G

13 Applicability of diatom indices for monitoring water quality 43 REFERENCES Ács É., Szabó K., Hindáková A., Kiss K.T., 2003, Use of diatom indices for the water qualification of the river Danube and some of its tributaries (from Germany to Hungary), [in:] Use of algae for monitoring rivers, Abstracts of 5 th International Symposium, Cracow, September, 2003, 49 Bogaczewicz-Adamczak B., Koźlarska I., 1999, The evaluation of the water quality in the Swelinia Stream on the basis of diatom analysis, Oceanol. Stud., 28 (1-2), Bogaczewicz-Adamczak B., Kłosińska D., Zgrundo A., 2001, The diatoms as indicators of water pollution on the coastal zone of the Gulf of Gdańsk (Southern Baltic Sea), Oceanol. Stud., 30 (3-4), Cemagref, 1982, Etude des méthodes biologiques d appréciation quantitative de la qualité des eaux, Rapport Q.E. Lyon Agence de l Eau Rhône- Méditerranée-Corse, Lyon, 218 pp. Coste M., Ayphassorho H., 1991, Etude de la qualité des eaux du Bassin Artois- Picardie à l aide des communautés de diatomées bentiques (Application des indices diatomiques), Rapport Cemagref, Bordeaux - Agence de l Eau Artois-Picardie, Douai Dell Uomo A., 1996, Assessment of water quality of an Apennine river as a pilot study for diatom-based monitoring of Italian watercourses, [in:] Use of Algae for Monitoring Rivers II, Whitton B.A., Rott E. (eds.), Institut für Botanik, Universität Innsbruck, Denys L., 1991/92, A check-list of the diatoms in the Holocene deposits of the western Belgian coastal plain with a survey of their apparent ecological requirements. Service Geologique de Belgique. T. 1, 2. Descy J.P., 1979, A new approach to water quality estimation using diatoms, Nova Hedwigia, 64, Descy J.P., Coste M., 1991, A test of methods for assessing water quality based on diatoms, Verh. Internat. Verein. Limnol., 24, Dojlido J.R., 1987, The water chemistry (Polish), Arkady, Warszawa, 262 pp. Eloranta P., 1999, Applications of diatom indices in Finnish rivers, [in]: Use of algae for monitoring rivers III, Prygiel J., Whitton B. A., Bukowska J. (eds.), Agence de l Eau Artois-Picardie, Hofmann G., 1994, Aufwuchs Diatomeen in Seen und ihre Eignung als Indikatoren der Trophie, Bibliotheca Diatomologica 30, J. Cramer, Berlin, Stuttgart, 241 pp. Kawecka B., Kwandrans J., Szyjkowski A., 1999, Use of algae for monitoring rivers in Poland Situation and development, [in]: Use of algae for monitoring rivers III, Prygiel J., Whitton B. A., Bukowska J. (eds.), Agence de l Eau Artois-Picardie,

14 44 A. Zgrundo, B. Bogaczewicz-Adamczak Kelly M.G., Whitton B.A., 1995, The trophic Diatom Index: a new index for monitoring eutrophication in rivers, J. Appl. Phycol., 7, Kelly M.G., Whitton B.A., Lewis A., 1996, Use of diatoms to monitor eutrophication in UK rivers, [in]: Use of algae for monitoring rivers II, Whitton B. A., Rott E. (eds.), Institute für Botanik, Universität Innsbruck, Korzeniewski K., 1990, The rudiments of marine chemistry (Polish), Uniwersytet Gdański, Gdańsk, 198 pp. Krammer K., Lange-Bertalot H., 1986, Süßwasserflora von Mitteleuropa, Bacillariophyceae, VEB Gustav Fischer Verlag, Jena, Stuttgart 2/1, 876 pp. Krammer K., Lange-Bertalot H., 1988, Süßwasserflora von Mitteleuropa, Bacillariophyceae, VEB Gustav Fischer Verlag, Jena, Stuttgart 2/2, 569 pp. Krammer K., Lange-Bertalot H., 1991a, Süßwasserflora von Mitteleuropa, Bacillariophyceae, VEB Gustav Fischer Verlag, Jena, Stuttgart 2/3, 576 pp. Krammer K., Lange-Bertalot H., 1991b, Süßwasserflora von Mitteleuropa, Bacillariophyceae, VEB Gustav Fischer Verlag, Jena, Stuttgart 2/4, 437 pp. Kwandrans J., 2000, The benthic diatom flora in small forest streams with different water trophy level and ph status (Pogórze Wielickie Hills, southern Poland), Acta Hydrobiol., 42, Kwandrans J., Eloranta P., Kawecka B., Wojtan K., 1999, Use of benthic diatom communities to evaluate water quality in rivers of southern Poland, [in]: Use of algae for monitoring rivers III, Prygiel J., Whitton B. A., Bukowska J. (eds.), Agence de l Eau Artois-Picardie, Lange-Bertalot H., 1979, Pollution tolerance of diatoms as a criterion for water quality estimation, Nova Hedwigia 64, Lecointe C., Coste M., Prygiel J., 1993, Omnidia : software for taxonomy, calculation of diatom indices and inventories management, Hydrobiologia 269/270: Leclerq L., Maquet B., 1987, Deux nouveaux indices chimique et diatomique de qualité d eau courante. Application au Samson et à ses affluents (Bassin de la Meuse Belge). Comparaison avec d autres indices chimiques biocénotiques et diatomiques. Inst. r. Sci. Nat. Belgique, doc. trav., 38, 113 pp. Lepš J., Šmilauer P., 1999, Multivariate analysis of ecological data, (accessed ) Pankow H., 1990, Ostsee-AlgenfloraI, Gustav Fischer, Jena, 648 pp. Prygiel J., Coste M., 1996, Recent trends in monitoring French rivers using algae, especially diatoms, [in]: Use of algae for monitoring rivers II, Whitton B. A., Rott E. (eds.), Universität Innsbruck, 87-96

15 Applicability of diatom indices for monitoring water quality 45 Prygiel J., Lévêque L., Iserentant R., 1996, Un nouvel indice diatomique pratique pour l évaluation de la qualité des eauxen réseau de surveillance, Rev. Sci. Eau, 1, Prygiel J., Coste M., Bukowska J., 1999, Review of the major diatom-based techniques for the quality assessment of rivers State of the art in Europe, [in]: Use of algae for monitoring rivers III, Prygiel J., Whitton B. A., Bukowska J. (eds.), Agence de l Eau Artois-Picardie, Rakowska B., Study on diatom diversity in water ecosystems of Polish Lowlands (Polish), Wydawnictwo Uniwersytetu Łódzkiego, Łódź, 75. Schiefele S., Schreiner C., 1991, Use of diatoms for monitoring nutrient enrichment, acidification and impact of salt rivers in Germany and Austria, [in:] Use of Algae for Monitoring Rivers, Whitton B.A., Rott E., Friedrich G. (eds.), Universität Innsbruck, Innsbruck, Sládeček V., 1986, Diatoms as indicators of organic pollution, Acta Hydrochim. Hydrobiol., 14, Snoeijs P., 1993, Intercalibration and distribution of diatom species in the Baltic Sea, Opulus Press Uppsala, 1, 129 pp. Snoeijs P., Vilbaste S., 1994, Intercalibration and distribution of diatom species in the Baltic Sea, Opulus Press Uppsala, 2, 126 pp. Snoeijs P., Potapova M., 1995, Intercalibration and distribution of diatom species in the Baltic Sea, Opulus Press Uppsala, 3, 126 pp. Snoeijs P., Kasperovičiene J., 1996, Intercalibration and distribution of diatom species in the Baltic Sea, Opulus Press Uppsala, 4, 126 pp. Stachura K., Witkowski A., 1997, Response of the Gulf of Gdańsk diatom flora to the sewage run-off from the Vistula river, Fragm. Flor. Geobot. 42 (2), Ter Braak C.J.F., 1986, Canonical correspondence analysis: A new eigenvector technique for multivariate direct gradient analysis, Ecology, 64, Ter Braak C.J.F., 1994, Canonical community ordination. Part I: Basic theory and linear methods, Eoscience, 1 (2), Ter Braak C.J.F., Prentice I.C., 1988, A theory of gradient analysis, Adv. Ecol. Res., 18, Ter Braak C.J.F., Šmilauer P., 2002, CANOCO Reference manual and CanoDraw for Windows User s guide: Software for Canoinical Community Ordination (version 4.5), Microcomputer Power (Ithaca, NY, USA), 500 pp. Trojan P., 1975, General ecology (Polish), PWN, Warszawa, 419 pp. Trzosińska A., Falkowska L., Pęcherzewski K., Neugebauer E., 1980, Chemical analysis of a sea water, Methodological guide to sea water chemistry (Polish), Uniwersytet Gdański, Gdańsk, 146 pp.

16 46 A. Zgrundo, B. Bogaczewicz-Adamczak Van Dam H., Mertens A., Sinkeldam J., 1994, A coded checklist and ecological indicator values of freshwater diatoms from the Netherlands, Neth. J. Aquat. Ecol., 28(1), Watanabe T., Asai K., Houki A., 1986, Numerical estimation to organic pollution of flowing water by using epilithic Diatom Assemblage Index (DAIpo), Sci. Tot. Environ., 55, Witkowski A., Lange-Bertalot H., Metzeltin D., 2000, Diatom flora of marine coasts I, A.R.G. Gantner Verlag K.G., Ruggell, 925 pp. Wojtal A., Witkowski A., Metzeltin D., 1999, The diatom flora of the Bór na Czerwonem raised peat-bog in the Nowy Targ Basin (Southern Poland), Fragm. Flor. Geobot., 44(1), Wróbel S. 1988, Ekochemistry of inland waters (Polish), [in:] Ekologia wód śródlądowych. Wybrane zagadnienia, Kajak Z. (ed.), PWN, Warszawa, pp.252 Zgrundo A., Bogaczewicz-Adamczak B., 2002, Diatom pollution indices as a tool for monitoring coastal zone waters on the example of the Gulf of Gdańsk, [in:] Estuaries and other brackish areas pollution barriers or sources to the sea? Proceedings of ECSA Symposium 34, Gdańsk-Sopot, 2002, de Jonge V., Elliot M. (eds.), ECSA, IO PAS and Polish SCOR, 97