Igor M. Primakov and Polina Nikolaenko

Plankton Communities in the Neva Bay during the 20th Century

This study provides an overview on the phyto- and zoo- plankton studies made of the Neva Bay and of the changes that have taken place in the plankton community during the 20th century. It is known that plankton respond to changes in water quality, especially to changes in the content of organic matter. Comparisons of the literature data reveal the value of species as indicators of different conditions. Many plankton species in the Neva Bay show great year-to-year fluctuations due to varying environ- mental conditions. According to the results of studies conducted in 1911-1990, freshwater plankton species have dominated in the Neva Bay. The plankton community has essentially consisted of species transported from Lake Ladoga. Brackish-water species occasionally occurred in the plankton samples of the Neva Bay. High turbidity and rapid throughflow of water limit algal production in the bay and, due to the high outflow, the europhication effects of the catchment area are mainly conducted into the Gulf of Finland.

INTRODUCTION The socioeconomic development of St. Petersburg, the largest city on the coast of the Baltic Sea, has had a significant impact on the water quality of the Neva Bay. This bay serves as the recipient of all sewage produced in St. Petersburg. In turn, the water quality determines the qualitative and quantitative struc- ture of fauna and flora in the bay. Problems with water quality are mainly connected to wastewater disposal and to the flood dam.

The history of hydrobiological studies in the Neva Bay is as long as 100 years. Already in the 1 9th century extensive studies were undertaken to describe species diversity. Studies on the hydrochemistry, sanitary conditions, qualitative and quantitative communities of nlankton and zoobenthos in the 20th century pro- vide data for long-term evalua- tion of the changes in the phyto- and zooplankton communities (1-14).

The aim of this article is to present the history of plankton studies carried out in the Neva Bay and to evaluate the develop- ment of plankton communities in the 20th century.

STUDY AREA Neva Bay is part of the Gulf of Finland. In the east, the mouth of the Neva river serves as its border, and in the west the bor- der runs along a line from Lisiy Nos through Kronstadt to Lo- monosov. Today, the western border follows the flood barrier. The length of the bay is 21 km, its greatest width is 15 km, and its total area is 329 km2. The av-

erage depth of the bay is between 3 and 5 m, and its volume is 1.2 km3. On an average, the water flow from the Neva river into the bay is 2500 m3 s-1, or 78.9 km3 yr-'. The Neva Bay is con- nected to the Gulf of Finland by two straits at Kotlin Island, i.e. the northern and southern waterways with widths of between 9 and 10 and between 5 and 7 km, respectively. From the east to the west, the bay is divided by a marine channel, constructed in 1885; 80-100 m wide, 12 m deep when dredged, and 30 km long (15).

The Neva Bay, despite being a part of the Baltic Sea, remains a freshwater reservoir. Brackish waters can enter the bay from the Gulf of Finland along the bottom of the northern waterway and the marine channel, nevertheless, this has no appreciable in- fluence on the hydrochemical and hydrobiological regimes of the bay (15).

HISTORICAL SURVEY OF PLANKTON STUDIES IN THE NEVA BAY The history of hydrobiological studies on the Neva Bay may be divided into 3 periods. The aim of the research during the pe- riod from 1905-1937 was to determine the preconditions and locations for installing sewer outlets for the municipal sewer- age system. The second period (1956-1964) was devoted to ob- taining assessments of the water quality by specialists from the State Research Institute of Lake and River Fishery, and Zoologi- cal Institute (USSR Academy of Sciences). The last period, start- ing at the end of the 1970s, was in connection with the construc- tion of a large-scale complex of structures with the aim to pro- tect St. Petersburg (Leningrad) from floods and to establish mu- nicipal wastewater-treatment plants. At that time, hydrobiological monitoring of the Neva Bay was arranged by the North-West Administration of the Federal Service of Russia for Hydro- meteorology and Environmental Monitoring (Sevzaphydromet). In addition, studies of the circulation of substances and the in- fluence of biological factors on the water quality in the Neva Bay and the eastern Gulf of Finland were made by the Zoologi-

Figure 1. Study area

. ~~~and the sampling

. ~~~~stations in

~~~' ~~~~~~~ ~~Stations position in the Neva Bay during different study periods:

~~~~~~~~~~~~~~~tain ic 90t 91() w, Stations since 1920 to 1921 (4).

Sf Stations since 19358 to 1937 (7).

Stations of North-West Administration of Federal ~ ~ ~ . ..~., ,... ;:~ Y~. Y ~ Service of Russia for

Hydrometeorology and Environmental Monitoring (Sevzaphydromet) since

*Stations of Zoological Institute since 1982 to 1984 (10, 1 1).

292 ?D Royal Swedish Academy of Sciences 2001 Ambio Vol. 30 No. 4-5, August 2001 http://www.ambio.kva.se

cal Institute (USSR Academy of Sciences) in 1981-1984 and by the State Hydrological Institute in 1982-1988.

1905 The first plankton studies were carried out by A.S. Skorikov in 1905 in connection with work done by the city of St. Petersburg to improve the municipal water supply system. Al- together, 28 samples were collected in September and October from 10 stations located along the ma- rine channel and in the proximity of Kotlin Island (1). Skorikov concluded that the plankton in the Neva Bay are "essentially the same as in the Neva River and Lake Ladoga, but some prevailing spe- cies apparently do not coincide in their phases of periodicity". The publication does not include any detailed plankton data.

1911-1914 The next plankton study was undertaken by S.V. Visloukh, a member of an expedition headed by G.V. Khlopin (16). Plankton samples were col- lected from 31 stations in coastal and central parts of the bay from July 1911 until September 1912 and in 1914 from July to September (2, 3). Mixed sam- ples of plankton were taken with a Folk plankton pump, an Apstein plankton net (No. 20) and a Nadson's set for the bottom samples. They were preserved with formaldehyde. During this period 375 plankton samples were collected, including water samples taken in May-early July 1912, and these were quantitatively analyzed. Visloukh made a list of notes on the ecological characteristics of algae and seasonal changes of species composition. Altogether 99 species and forms of algae were de- scribed, relating to the following groups: Cyano- phyta 20; Cryptophyta 2; Dinophyta 1; Chrysophyta 12; Bacillariophyta 27; Xantophyta 1; Eugleno- phyta 5; and Chlorophyta 31. Taxa were classified in 5 groups: very common, common, not rare, rare, and very rare. Visloukh also studied zooplankton, with his species list including 45 taxa of the most abundant zooplankton species (Protozoa 19, Rotatoria 21, Cladocera 3 and Copepoda 2).

In late spring, the following genera of Bacil- lariophyta generally dominated: Aulacoseira is- landica (and A. italica), Asterionella formosa, Diatoma sp. and Tabellaria flocculosa and T. flocculosa v. asterionelloides (in the original paper Melosira islandica and M. italica, Asterionella gracillima and Tabellaria fenestrata and T. fenestrata v. asterionelloides). In summer, diatoms Tabellaria flocculosa and Asterionella formosa very often dominated, but chrysomonads Uroglena spp. (Uroglenopsis sp.) and Dinobryon spp. and Chlorococcales Sphaerocystis shroeteri could also dominate or be abundant. The same species that were dominant in autumn remained so in spring, but not Diatoma sp.

There may have been some uncertainties in the species determination. Visloukh described flagel- lated forms of Sphaerocystis schroeteri in some samples. The species could have been Pseudo- sphaerocystis lacustris, which later became abun- dant in the Neva Bay. Also, Sphaerocystis shroeteri could have been a combination of several genera of Chlorophyta colonies, which are even today dif- ficult to identify.

The quantitive samples taken in May-early July

1912 were dominated by the aforementioned diatoms, in particu- lar, Diatoma sp. was abundant in some samples. Plankton abun- dances were relatively low or very low in June and early July. An example of the plankton results is given in Table 1.

Using plankton results, Visloukh determined the pollution de- gree for different parts of Neva Bay. The Marine Channel was

Table 1. Qualitative and quantitative results of plankton sampling done on 9 July 1912 at Station 205, at the mouth of the Neva River, Opposite to the entrance of the marine channel (3). s.h.= very common, h - common, n.s.= not rare, s = rare, as.. = very rare. Quantitative results are given as abundance In ml. Tabellarla and Asteronalla are counted as cells, Uroglena and Dinobryon as colonies. Flagellated forms are colorless. Muscle fiber, detritus of plants and textile fiber not rare. (A copy of the original study).

110t3AKa 9 iWoas 1912 r.

\ Cr. 205 (426), YcTbe S. Hesu npOTHN3'b sxoAa s-b MopcKog KaHaanh: rAy6ita 28 c.

laiKToIr s33b ray5rnib[ 7 (p. Uroglenopsis americana (Calk.) Lemm... . . . . . . . n. s. Tabellaria lenestrata (Lyngb.) Kg .. . . ..... h

a L asterionelloides Grun. . [ s h- Asterionella gracillima (Hinz) Heib ....... . h.

a solea W. Sm.. . ., . . s Oomphosphaeria Naegetiana (Unger) Lemnm. . . h. Dinobryon protuberans Lemm. ... . . . . . . h

B divergens ltmh ... . . . . . .h. Pediastruim boiyannm Mengh. . . . . .i. . . . . . n. S. (,m.o). Coelosphacrium Kutzingianurn NAgeli. n. s. Anurea cocldkaris Gosse ... . . .. .. .. . .. n. s. (pm0o) Kitrchnerietla uanars (Kirchi.) hoeb. ... . . . n, s. SphaeroCQys'is SchInceteri Chod . . . . . . . . .. n. s. Botryococcns b%.atuni .... . . . . . . . . . . S. ARnaae;;a Lernmermanni P. Richt ........ . S. Ceratium hirundinella 0. F. MM11. S. Ctadotkrix dichotoma Cohn . . . . . . . . . . S. (Pm)- nonepemonoaoc. JcXycbyAF soAoKa . . . . . . . S. St Destritus, pacTmreawtue ocTaTZs, aiiM TKaUeA. . . . n. S.

Bi9 I Ky6. cawT. ita Tofi we ray6HHt:

Tabellaria, IlT ., .i . . . .... . 4 Asterionela, T .. . . . . . . . . . . . . . . . 3 Uroglenopsis, Kooitii . . . . . . . . . . . . . 5 Dinobryon, tcoaotfifi . . . . . . . . . . . . .. I Flagellata 6e3ALTHjtm.. . ... OK. 100

Figure 2. The results of the bacteriological study made on June-November 1911 in the Neva Bay. At the mouth of Neva River the number of saprophyte bacteria colonies was rather low (2080), whereas in the marine channel it was as high as 20 620 colonies mr1 according to Khlopin 1913 (16).

AY%J1 %*

0 5720 T360j

- ~ ~^ - 850 4

50 4175 A,C I"wd

4460 so~~~~~~47 28

40070

A -Ar ~~~~4e690

70

S ( & Mis^?4 r4?s4~~~~~~~~~~262

- hJ

Ambio Vol. 30 No. 4-5, August 2001 C Royal Swedish Academy of Sciences 2001 293 http://www.ambio.kva.se

i eflood

found to be the most polluted area. The northern part was more polluted than the southern part due to the summer garbage dump located on the northern shore. The cleanest sites were situated between Lisiy Nos and Kronstadt. The results of bacteria stud- ies provided additional information about the condition of the Neva Bay (Fig. 2). Sphaerotilus natans, an indicator of wastewater, was common in the most polluted areas of the bay, near dumps and sewer outlets, for example.

1920-1921 A more complete and detailed study of plankton in the Neva Bay was done by I.A. Kiselev and V.M. Rylov. From July 1920 to June 1921 about 50 samples were taken along a line extending from Lisiy Nos to Petergoff, and also near Kronstadt, but there was not a single station with a complete 12-month series of sam- pling covering an annual cycle as a whole (Fig. 1). The sam- ples were taken once or twice per month from a steamer with the help of an Apstein net (No. 68); in December and January

Table 2. Typical plankton species in the Lake Ladoga (left) and the Neva Bay in the 1920s (5). Note the cyanobacteria Planktothrix (Oscillatoria) agardhli and Anabaena spp. in both tables and Microcystis sp. in the Neva Bay. These species did not dominate In the bay (5), but net sampling itself may have enriched large plankton forms. (A copy of the original study).

iIaAoZcXoe 03epo. j Hec Cxax ry6a.

Asterionella, Melosira (islandica) Ta- Asterionella, Melosira(granulata. lslan- bellaria(fenestrata), Attheya, Rhizo- dlca, itallca), Tabellaria(fencstrata), solenia (longiseta, criensis, morsa) Attheya, Rhizosolenia (longiseta.

eriensis, morsi).

Synedra (acus). Synedra (acus).

Closterlumn (aciculare, pronum). Closterium (Kiltringianumn. aciculare).

Cosmarium (subtumldum). Staurastrum Cosmarium (sudtumidum). Staura- (paradoxum, pseudopelagicum, lu- strum (paradoxum. lunatum, pseu- natum). dopelagicum, dejectum).

Sphaerocystis, Botryococcus. Pedia- Sphacrocystis, Botryococcus, Pedia- strumn. strum, Dictyosphacrium.

Conferva (depauperata?). Conferva tdepaupereta?)

Ceratium. Peridinium (tabulatum, Ceratium, Peridinlum (tabulatum, cinc- willel). tum).

Dinobryon, Mallomonas, Uroglena. Dinobryon, Mallomonas, Uroglena.

Comphosphaeria (Naegeliana, Ana- Gomphosphaeria (Naegeliana), Ana- baena(Lemmermannl, spiroldes. ma- baena (spiroldes. macrospora. Lem- crospora, ellipsoides etc.), Oscilia- mermanni), Oscillaria (AgardhHi), ria (Agardhill. Microcystis.

Aphanisomenon. Aphanisomenon.

The northern shore of the Neva Bay in the vicinity of Lahta. Photo: S. Chivilev.

The northern part of the flood barrier. Photo: S. Chivilev.

samplings were made through a hole in the ice. The samples were preserved with formaldehyde. During this period, 100 phyto- and zooplankton samples were collected (4, 5).

Kiselev (5) presented 139 phytoplankton species from the fol- lowing groups: Cyanophyta 15; Cryptophyta 2; Dinophyta 4; Chrysophyta 11; Bacillariophyta 47; Xantophyta 1; Eugleno- phyta 6; Chlorophyta 53. Taxa were classified in 5 groups ac- cording to cell density in the counting chambers. The most com- mon species in June-August 1920 were as follows: Sphaerocystis schroeteri, Dinobryon spp., Asterionellaformosa (originally A.

gracillima) and Tabellaria flocculosa v. asterionelloides (originally T. fenestrata v. asterionelloides). Rylov (4) presented a systematic review of 156 zooplankton species (Protozoa 15, Rotatoria 93, Cladocera 33 and Copepoda 15).

This study led to a considerable increase in the knowledge about algae due to the description of phytoplankton seasonal changes and the conclu- sions drawn in regard to the similarity of phytoplankton in the Neva Bay and Lake Ladoga (Table 2).

1935-1937 A continuous, 2-year quantitative study of the zooplankton community in the Neva Bay was made in the mid-1930s by the Hydrobiological Laboratory of Petergoff Biological Institute (today Biological Research Institute of St. Petersburg State University). The plankton studies were done by E.I. Kiseleva and M.F. Sokolova (6, 7). From February 1935 to January 1937, 3 stations were sampled near the southern coast (Fig. 1). Mixed samples of phytoplankton were taken with a plank- ton pump and with Juday and Apstein plankton nets. Quantitative zooplankton samples were taken with a small Juday net, and a significant part of the zooplankton samples were collected by the plankton pump in 1936. All samples were pre- served with formaldehyde. Kiseleva's qualitative study is based on 72 phytoplankton samples. The phyto- and zooplankton quantitative samples as well as 9 qualitative zooplankton samples were studied by Sokolova. The zooplankton analysis

294 ? Royal Swedish Academy of Sciences 2001 Ambio Vol. 30 No. 4-5, August 2001 http://www.ambio.kva.se

were done using the Genzen counting method. Kiseleva (6) found 290 species and forms from the following

groups: Cyanophyta 25; Cryptophyta 1; Dinophyta 5; Chryso- phyta 23; Bacillariophyta 161; Xantophyta 1; and Chlorophyta 74. Taxa were classified in 6 groups according to frequency. The most common species during spring and autumn were diatoms Aulacoseira islandica, Asterionella formosa, Fragilaria cro- tonensis and Tabellaria flocculosa with the addition of cyano- bacteria Woronichinia naegeliana and Aphanizomenonflos-aq- uae in autumn. These cyanobacteria were relatively abundant also in summer, when diatoms A. formosa, T flocculosa, Diatoma tenuis and chrysomonads Dinobryon spp. were domi- nant.

According to quantitative results, abundances of the dominant species of net phytoplankton samples were low. However, we lack information on the small species which escaped through the net (7). The species list of zooplankton included 167 taxa; the main groups were: Protozoa 58; Rotatoria 73; Cladocera 21; and Copepoda 9. Kiseleva and Sokolova classified the Marine Chan- nel as the most polluted area in Neva Bay.

1962-1964 In 1962-1964 L.A. Kutikova (8) collected qualitative data on Rotatoria from the Neva Bay from 7 stations of the Lahta-Strelna transect (Fig. 1). The plankton samples were collected with Zep- pelin net (No. 67) and preserved in formalin. Kutikova listed 4 species of Rotatoria in the Neva Bay and 17 species in the mouth of the Neva River. Studies indicated that the self-purification zone was located in the western part, and that the Marine Chan- nel and the northeastern shallow part of the bay were the most polluted areas.

1982-1984 From May 1982 to October 1984, environmental studies in Neva Bay were performed by the Zoological Institute of the Russian Academy of Science (9-13). The sampling was carried out at the stations indicated in Figure 1. Zooplankton sampling was car- ried out 1-5 times during the vegetation season. In 1982, zooplankton were sampled using a medium Juday net (No. 68) in the central part of the bay. In 1983-1984, net No. 72 was used. The near-to-bottom quantitative samples were taken by a Patalas sampler in which 10-20 liters of water were filtered through a plankton net (No. 70). A total of 570 samples were collected. Phytoplankton biomass was calculated in a Nogot chamber (0.05-0.02 ml). The qualitative samples were analyzed for Rotatoria species. The zooplankton counting was carried out in a Bogorov chamber (14).

A total of 402 plankton groups were recorded: Cyanophyta 40; Cryptophyta and Dinophyta 8; Chrysophyta 1; Bacillario- phyta 52; Xanthophyta 13; Euglenophyta 9; Chlorophyta 91; Rotatoria 95; Cladocera 56 and Copepoda 37. The following phytoplankton species were dominant in the Neva Bay: cyano- bacteria Aphanocapsa incerta, Microcystis aeruginosa, Aphani- zomenon flos-aquae, Limnothrix planctonica; diatoms Aula- coseira islandica and D. tenuis and xanthophycean Tribonema affine. Of these especially A. incerta, Microcystis aeruginosa and Limnothrixplanctonica demand high levels of nutrients. By that time, the diatom Skeletonema subsalsum, which favors eutrophied, low salinity areas of the Baltic Sea, was noted as a new species for the bay. In 1982-1988, researchers noticed a large number of Oscillatoriales, which indicates organic pollu- tion.

Of 233 species found in the zooplankton of the Neva Bay in 1982-84, 139 (60%) were in Lake Ladoga. The zooplankton of the central water area of the Neva Bay represented initially the plankton of Lake Ladoga, transformed in the Neva river (12, 13). The fauna of the Neva Bay was enriched with species which maturated in shoal reservoirs and ponds, located along southern

coast of the Neva Bay. There were numerous representatives of Brachionus spp., absent in Lake Ladoga. Waters from the east- ern part of the Gulf of Finland brought some brackish-water spe- cies into the Neva Bay.

1978-1990 Since 1978, the Northwest Administration of the Federal Serv- ice of Russia for Hydrometeorology and Environmental Moni- toring (Sevzaphydromet) has sampled 22 stations regularly (Fig. 1). The minimum sampling frequency is three times a year (May, August, October). Zooplankton samples were collected as total trappings using medium and small Juday nets (No. 55). The sam- ples were fixed in formalin and Kuzmin fixative (17). Zooplankton counting was conducted in a Bogorov chamber.

In 1978-1990, the summer phytoplankton composition changed: there was a significant increase of cyanobacteria ac- companied by a decrease in green algae (17). During the first period the diatom A. islandica, the green alga Pandorina morum, the filamentous green algae Microspora spp. and Mougeotia spp., and the xanthophycean Tribonema affine were dominant. One indication of ecosystem changes during 1986-1990 was the mas- sive increase of cryptomonads, which dominated together with cyanobacteria Woronichinia naegeliana.

DEVELOPMENT OF PLANKTON COMMUNITIES In 1910-1990 the plankton in the Neva Bay was studied repeat- edly. The list of phytoplankton organisms included 604 species and forms known in the Neva Bay. The most diverse group was Chlorophyta (3 8.7%), followed by Bacillariophyta (36.1%), and Cyanophyta (15.2%). The sampling methods and sampling lo- cations differed throughout the period, and quantitative data were scarce at the beginning of the century. It was necessary to choose the qualitative approach to estimate the long-term variability of species composition and the plankton dominance. For this pur- pose, the original lists of plankton species where the dominant species were determined were re-examined (Table 3).

Table 3. Dominating algal taxa in May-September samples in 1911-1990 (2, 3, 5, 6, 9, 12).

Taxa 191 1-1921 1935-1937 1978-1990

Cyanophyceae Microcystis aeruginosa 1 + Chroococcales (small cells) + Woronichinia naegeliana + + + Aphanizomenon flos-aquae + Limnothnx planctonica +

Osclllatoriales + Cryptophyceae Cryptomonas spp. + Ceratium hirundinella + + Chrysophyceae Dinobryon spp. + + + Uroglena spp. + + +

Bacillariophyceae Aulacoseira islandica + + + Skeletonema subsalsum + Asterionella formosa + + Fragilaria crotonensis + Diatoma tenuis + + + Tabellaria flocculosa + +

Xanthophyceae Tribonema sp. + +

Chlorophyceae Pandonina morum ??+ Pseudosphaerocystis lacustris + Dictyosphaerium puichellum + Micractinium pusillum + Monoraphidium arcuatum + Pediastrum spp. + + Scenedesmus spp. + Sphaerocystis schroeteri? + + Microspora sp. + Mougeotia sp. *

Ambio Vol. 30 No. 4-5, August 2001 ? Royal Swedish Academy of Sciences 2001 295 http://www.ambio.kva.se

In 1911-1990, the dominating taxa have been mainly of fresh- water origin. Occasionally, water masses enter the Neva Bay from the Gulf of Finland, bringing brackish-water plankton spe- cies into the bay. In the 1980s, the brackish-water species, S. subsalsum, was occasionally abundant in the bay. Moderately small taxa, like P. morum and Scenedesmus spp., were present in small amounts in earlier samples, but due to sampling with a net, there may have been a certain amount of escape through the nets. On the other hand, as a net can collect a very large vol- ume of water, rare species might have been included in the plank- ton lists.

The long period 1978-1990 has a variety of dominant spe- cies and an extensive species list. The main dominant species of earlier years, diatoms T. flocculosa and A. formosa, which are very common species in clean or moderately eutrophic fresh- waters, were not among the dominant species in 1978-1990. According to Basova and Lange (17), the Neva Bay is suffer- ing from significant anthropogenic effects, but due to high tur- bidity and rapid water exchange, phytoplankton biomasses were limited in the period 1978-1990. The latest significant change- in the late 1980s-was a massive growth of cryptomonads. Cyanobacteria and green filamentous algae have also increased, indicating increasing eutrophy. Nevertheless, the major impact of the eutrophying substances is transferred to the Gulf of Fin- land (17).

The list of zooplankton species contains a total of 278 spe- cies, the majority of which are Rotatoria (44%), and Protozoa (22%), Cladocera (21%), and Copepoda (13%). The changes in the dominating taxa are presented in Table 4.

A comparison of the structure of the zooplankton community shows that the abundance of Cladocera and Copepoda species increased in the 1980s. Series of species described by Rylov (4) in the 1920s as infrequent (Bosmina obtusirostris, Chydorus sphaericus, Mesocyclops leuckarti), prevailed in the Neva Bay in the 1980s and had a leading position among other Crustacea (13).

CONCLUSIONS Freshwater species dominated the plankton in the Neva Bay dur- ing the study period. The plankton essentially consisted of spe- cies transported from Lake Ladoga, and the bay water was mixed with brackish-water species only to a limited extent. At present, Neva Bay is suffering from significant anthropogenic effects, which are already visible in the phytoplankton communities as well as in the increase in littoral filamentous green algae. In com- parison to the first half of the century, the abundances of Cladocera and Copepoda species have increased. Taking into account the low algal biomasses, the condition in the Neva Bay

Table 4. Dominating zooplankton taxa in the Neva Bay from 1920 to 1984 (4, 7 10, 11).

Taxa 1920-1921 1935-1936 1982-1984

Protozoa Tintinnidium fluviatile + Tintinnopsis spp. + +

Rotatoria Conoohilus unicornis + + FiUnina longiseta + Gastropus stylfr + KeraFtel:la cochlearis + +: Keratella quadrata + + Notholca acuminata + + Notholca logspina + + Plososoma :truncatum + Polyarthra platyptera :+ + Synchaeta spp. + : + +

Cladlocera : Bosmina obtusirostris V :: +:

Chydorus sphaericu: + Copepoda

Mesocyclops leuckarti +

has been satisfactory during the 20th century. Apparently, this is connected to the specific hydrodynamics of Neva Bay, which ensure transit of a significant part of eutrophic and polluting sub- stances from the River Neva to the eastern Gulf of Finland.

References (The English titles of Russian publications in parentheses are indicative of the content of the publication).

1. Skorikov, A.S. 1910. K faune Nevskoy guby i okrestnyh vod ostrova Kotlin (To a fauna of Neva Bay and neighbouring waters of an island Kotlin). Ezhegodnik Zool. museja Akad. nauk. V. 15. 474-489. Petrograd. (In Russian).

2. Visloukh, S.M. 1913. Kratkiy otcheyot o biologicheskih issledovaniyakh Nevskoy guby v 1911-1912 godah (A summary of the biological survey in the Neva Bay in 1911- 1912). In: Materialy k izucheniju Nevskoj guby (Materials to study of the Neva Bay). Sankt-Peterburg, pp. 215-312. (In Russian).

3. Visloukh, S.M. 1921. K poznaniju mikroorganizmov v Nevskoj gube (Towards a knowl- edge of micro-organisms in the Neva Bay). Tr. Russ. Gidrolog. Inst., vyp. 1-3, 83-96. (In Russian).

4. Rylov, V.M. 1923. Zooplankton Nevskoj guby (Zooplankton of the Neva Bay). In: Issledovaniya reki Nevy i eyo bassejna (Researches of the River Neva and Its basin), 3. Petrograd, 85 pp. (In Russian).

5. Kiselev, I.A. 1924. Fitoplankton Nevskoi guby i vostochnoi chasty Finskogo zaliva (Phytoplankton in the Neva Bay and the eastem Gulf of Finland). Izv. Ross. Gidrolog. Ins., 88 pp. (In Russian).

6. Kiseleva, E.I. 1949. Issledovania fitoplanktonajugo-zapadnodnoj chasti Nevskoj guby (A phytoplankon study in the south-westem part of the Neva Bay). Uchyon. zapiski Leningr. un-ta. Serija biol. nauk, vyp. 21. 126, pp. 142-177. (In Russian).

7. Sokolova, M.F. 1949. Kolichestvennyj uchyot planktona otkrytogo i pribrezhnogo rajonov Nevskoj guby (The quantitative account of a plankton in the open part and coastal waters of the Neva Bay). Uchyon. zapiski Leningr. un-ta. Serija biol. nauk, 21, 126, pp. 67-106. (In Russian).

8. Kutikova, L.A. 1968. Vozmozhnosti ispolzovaniya kolovratok v biologicheskoy otsenke vody reki Nevy (Opportunities of use of the rotifers in a biological estimation of the River Neva water). In: Zagryaznenie i samoochischenie reki Nevy (Pollution and self- purification of the River Neva). Bykhovsky, B.E. (ed.). Leningrad, Nauka, pp. 193- 201. (In Russian).

9. Nikulina, V.N. and Anochina, L.E. 1987. Floristicheskij sostav planktona i perifitona (Plankton and periphyton composition). In: Nevskaja guba. Gidrobiologicheskie issledovanija (The Neva Bay. Hydrobiological Studies). Vinberg, G.G. and Gutelmakher, B.L. (eds). Leningrad, Nauka, pp. 14-20. (In Russian).

10. Pidgayko, M.L. 1987. Setnoy plankton otkrytoy chasti Nevskoy guby (The net zooplankton of an open part of the Neva Bay). In: Nevskaja guba. Gidrobiologicheskie issledovanija (The Neva Bay. Hydrobiological Studies). Vinberg, G.G. and Gutelmakher, B.L. (eds). Leningrad, Nauka, pp. 103-105. (In Russian).

11. Telesh, I.V. 1987. Kolovratki i rakoobraznie planktona (The rotifers and crustaceans of plankton). In: Nevskaja guba. Gidrobiologicheskie issledovanija (The Neva Bay. Hydrobiological Studies). Vinberg, G.G. and Gutelmakher, B.L. (eds). Leningrad, Nauka, pp. 82-103. (In Russian).

12. Telesh, I.V. 1986. Sovremennoe sostojanie zooplanktona Nevskoy gubi (Modem state of the zooplankton of the Neva Bay). Sbornik nauchnih trydov GosNIORH, vyp. 248, pp. 142-149. (In Russian).

13. Telesh, I.V. 1987. Zooplankton sistemi reka-estyariy na primere reki Nevi i Nevskoy gubi (The Zooplankton of a System the River-estuary on an Example of the Neva River and the Neva Bay). Candidate dissertation. Leningrad, 246 pp. (In Russian).

14. Rykovodstvo po metodam biologicheskogo analiza morskoy vodi i donnih otlozheniy (Manual on Methods of Biological Analysis of Sea Water and Bottom Sediments). 1980. Tsiban A.V. (ed.). Leningrad, Hydrometeoizdat, 192 pp. (In Russian).

15. Nezhikhovsky, R.A. 1981. Reka Neva i Nevskaja guba (The River Neva and the Neva Bay). Leningrad, Gidrometeoizdat, 1 10 pp. (In Russian).

16. Khlopin, G.V. 1913. Materials on the studies of the Neva Bay water in term of sani- tary condition. Report for municipal govemment, 47 pp. St. Petersburg. (In Russian).

17. Basova, S., and Lange, E. 1998. Trends in late summer phytoplankton in the Neva Bay and eastem Gulf of Finland during 1978 to 1990. Mem. Soc. Fauna Flora Fennica 74, 1-14.

18. The authors wish to thank Natalia Balashova and Serge Chivilev (St. Petersburg State University) for their help, and also especially to express the deepest gratitude to Svetlana Basova (Sevzaphydromet) for her valuable suggestions and comments during the com- pletion of this work.

Igor M. Primakov is a PhD student in the Department of Ichthyology and Hydrobiology at the St. Petersburg State University. He is working at the White Sea Biological Station, Zoological Institute, Russian Academy of Sciences. His work focuses on the monitoring of the mouth of Chupa Bay (Gulf of Kandalaksha, White Sea). His main scientific interests are the influence of various hydrological and hydrochemical parameters on the structure of plankton communities. His address: St. Petersburg State University, Dept. of Ichthyology and Hydrobiology, 16-Linia 29, 199 178 St. Petersburg, Russia. E-mail: igor@lP5790.spb.edu

Polina Nikolaenko is MSc in biology at the Department of Botany of the St. Petersburg State University. Her address is St. Peterburg State University, Department of Botany, University Embankment 7/9, 199 034 St. Petersburg, Russia. E-mail: rund-polina@mail.ru

296 ? Royal Swedish Academy of Sciences 2001 Ambio Vol. 30 No. 4-5, August 2001 http://www.ambio.kva.se