Phytoplankton Biomass and Species Composition in Northeastern Lake Ontario, April-November, 1965

J. Great Lakes Res., Oct. 1975.

Vol. 1(1):151-161.

Internat. Assoc. Great Lakes Res. PHYTOPLANKTON BIOMASS AND SPECIES COMPOSITION IN NORTHEASTERN LAKE ONTARIO, APRIL-NOVEMBER, 1965 Accepted 31 July, 1975

Scarborough

M.R. Sreenivasa and C. NaZewajko University of Toronto~ Toronto~ Ontatio

CoZZege~

Abstract. In 1965 phytoplankton at 11 stations in Northeastern Lake Ontario showed a spring-early summer maximum during which total phytoplankton volume ranged from 3.1 x 106~3/ml to 60.8 x 106~3/ml. Diatoms were the predominant group during this period. On an annual basis, diatoms accounted for 53%, flagellates 28%, Chlorophyta 13% and Cyanophyta 13% of the total phytoplankton volume. In most instances algae were identified to species level. Seasonal data are presented for species composition, as a percentage of the total phytoplankton volume. Average cell volumes of 80 species of algae encountered in this study are also included. INTRODUCTION Until recently (Munawar and Nauwerck 1971) data on the phytoplankton of Lake Ontario were few. The earliest comprehensive work prior to 1971 was that of Nalewajko (1966, 1967). Distinct differences were found in the species of diatoms in the inshore and offshore areas of the lake. On the basis of species composition and total phytoplankton volume the inshore areas appeared to be eutrophic and the offshore areas oligotrophic. Prior to this study and for the next few years, the work on Lake ontario phytoplankton was limited in extent either in area, preiod of sampling or in phytoplankton groups. In the Bay of Quinte area, Tucker (1948) stUdied the summer phytoplankton populations. McCombie (1967) made a quantitative and qualitative assessment of phytoplankton and compared it with Tuckers's date. Schenk and Thompson (1965) studied the phytoplankton of a filtration plant. Mich-

151

alski (1968) described the phytoplankton of Canadian inshore waters. Ogawa (1969) and Reinwand (1969) have smapled the entire lake for phytoplankton and diatoms respectively, but their sampling was confined to a single occasion. The part of Lake Ontario chosen for this study is the extreme Northeastern end between latitude 43 0 45' - 44 0 30' and longitude 76 0 00' - 77 0 00'. It supplements the data of Nalewajko (1966) who did not have extensive stations in the eastern basin of Lake Ontario and did not include all ~ algae in her enumeration. MATERIALS AND METHODS The location of the sampling stations is shown in Figure 1. Samples from Lake Ontario were collected by the PORTE DAUPHINE during synoptic cruises from April to November, 1965. Samples collected during cruises 0-65-13, 0-65-15, 0~65-l9, 0-65-21, 0-65-22, 0-65-23, and 0-65-26 were analysed. Sampling locations were designated by 11 stations. Refrigerated samples

SREENIVASA and NALEWAJKO

152

44' 00'

011 43'

SCALE

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10

20

20 25

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KILOMETRES

RESULTS AND DISCUSSION

45'

STATUTE MilES

o

cell volumes were calculated from dimensions of individuals present in the samples. The merits of cell volume over cell numbers, or areal standard units and packed cell volume have been discussed by several investigators (Bellinger, 1974; Davis, 1954; Lund, 1961, 1964; Nalewajko, 1966a, 1966b; Nauwerck, 1963) •

I

40

43' 30'

FIG. 1. Location of sampling stations in Lake Ontario, 1965.

preserved in Lugol's iodine were either diluted or concentrated depending on the abundance of phytoplankton. An aliquot equivalent to 1 ml of the original sample was enumerated in an inverted microscope (Uterm~hl, 1931) at a magnification of 250X. Prior to enumeration, species present in integrated samples were identified at higher magnification. Cyclotella spp. and smaller entities of Stephanodiscus were enumerated as centrics. Their proportion in each sample was later determined from. acid-clean~d Hyrax mounts. Since cell sizes of phytoplankton taxa are very variable, counts of cell numbers do not reliably reflect the phytoplankton biomass. For a better estimate, cell numbers were converted to cell volume. For several taxa, data were available in Nalewajko (1966b). For others,

Samples were examined from 11 stations (Figure 1). Data on numbers of individuals were converted to volume using values shown in Table 1. Table 2 shows the percentage composition of the species for the sampling period. As shown in Figure 2, the total phytoplankton volume at these 11 stations showed only one pronounced maximum in the spring; however, the possibility remains that lesser peaks may have been missed due to infrequent sampling. The spring maximum occurred earlier at Stations 4, 5, 6 and 9 than at the other stations. Spatial heterogeneity of phytoplankton was apparent, the stations differing considerably in phytoplankton volume, particularly during the spring maximum, where values ranged from 3.1 x 106~3/ml to 60.8 x 106~3/ml. No clear-cut distinction of the type reported earlier (Nalewajko, 1976) was possible between inshore and offshore stations. For example, the offshore Stations 4, 5, 10 and 11 developed larger populations than some inshore stations. A comparison of phytoplankton volume data with average values for Lake Ontario in 1970 (Munawar and Nauwerck, 1971) revealed two important differences. First, at our stations, maximum phytoplankton volume occurred in

PHYTOPLANKTON BIOMASS AND SPECIES COMPOSITION TABLE 1.

153

Cell volume data for 80 species of algae from Lake Ontario 1965.

Bacillariophyta

Cell Volume/]l

Asterionella formosa Hassa Coscinodiscus rothii (Ehr.) Kuetz Cyclotella atomus Hust C. comta (Ehr.) Kuetz C. kuetzingiana Thwaites C. meneghiniana Kuetz C. ocellata Pant Diatoma elongatum Agardh Fragilaria capucina Desm F. crotonensis Kitton Mastagloia lacustris Grun Melosira islandica o. MUll M. granulata (Ehr.) Ralfs Navicula viridula Kuetz Nitzschia acicularis A. Cleve N. sigma (Kuetz) Wm. Sm. N. sigmoidea (Ehr.) Wm. Sm. Rhizosolenia eriensis H. L. Sm. Stephanodiscus alpinus Hust. S. astraea (Ehr.) Grun S. astraea var. minutula (Kuetz) Grun S. binderanus (Kuetz) Krieger S. hantzschii Grun S. hantzschii var. pusilla (Grun) Krieger S. niagarae Grun S. tenuis Hust Surirella angustata Kuetz Synedra acus var. angustissima Grun. S. acus var. radians (Kuetz) Hust S. montana Krasske S. ulna (Nitzsch) Ehr. Tabellaria fenestrata (Lyngb.) Kuetz

800 2330 200 570 900 1760 780 1280 500 750 2400 2330 1690 2400 280 4070 5200 3000 2010 8840 900 865 750 400 11840 1800 2360 1100 825 200 2010 4800

Chlorophyta

Ankistrodesmus sp. Corda Chlamydomonas sp. Ehrenb. Closterium sp. Nitzsch Coelastrum microporum Naegeli Cosmarium sp. Crucigenia quadrata Morren Desmatractum indutum (Geitler.) Pascher Dictyosphaerium pulchellum Wood Elakotothrix gelatinosa Wille Eudorina elegans Ehr.

250 340 90 900 6600 70 50 230 100 640

3

154

SREENIVASA and NALEWAJKO Chlorophyta (Contd.)

Franceia ovalis (Franee) Lemmerman Golenkinia radiata (Chod.) Wille Kirchenriella sp. Schmidle Lagerheimia subsalsa Lemmermann Micractinium pusillum Fresenius Oocystis borgei Snow Pediastrum biradiatum Meyen P. Boryanum (Turp.) Meneghini P. duplex Meyen P. simplex (Meyen) Lemmermann P. tetras (Ehr.) Ralfs Scenedesmus bijuga (Turp.) Lagerheim S. dimorphus (Turp.) Kuetz S. quadricauda (Turp.) Breb. S. quadricauda var.quadrispina (Chod.) Schroederia setigera Lemmermann Sphaerocystis schrieteri Chodat Staurastrum oaradoxum Meyen Tetraedron caudatum (Corda) Aansgirg T. minimum (A. Braun) Hansgirg

G.M. Sm.

490 385 50 940 65 400 384 400 196 U5 210 156 565 800 305 408 480 3000 950 575

Cyanophyta

Anabaena sp. Aphanocapsa sp. Chroococcus sp. Gomphosphaeria aponina Kuetz G. naegeliana (Unger) Lemmermann

108 38 900 40 60

Flagellates Chrysophyta

Dinobryon sociaZe Ehr. Pseudokephyrion sp.

735 160

Euglenophyta

Trachelomonas

sp.

730

Pyrrophyta

Ceratium hirundinella (G.F. Cryptomonas erosa Ehr. C. ovata Ehr. Glenodinium sp. Gymnodinium sp. G. helveticum Pennard Peridinium sp. P. cine tum (Mell.) Ehr. Rhodomonas minuta Skuja

Muell.) Dujardin

35000 5350 6720 1675 3694 8330 16600 52360 380

PHYTOPLANKTON BIOMASS AND SPECIES COMPOSITION

155

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SREENIVASA and NALEWAJKO

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May-June and not during July-September. Second, the average value during these population peaks was 21.5 x 10 6 ~3/ml compared with the 1970 whole lake average of 8.6 x 106~3/ml. However, as noted by Nalewajko (1967) and Munawar and

Nawuwerck (1971), spatial heterogeneity exists in phytoplankton distribution, particularly in in~hore areas. A more valid comparison can perhaps be made between the same locations in 1965 and 1970. Thus, station 9~ (Fig. 4, Munawar and Nauwerck, 1971) in 1970 was close to our station 5 in 1965 (Fig. 2). A maximum occurred at both stations in the spring, reaching about 6.5 x 106~3/ml in 1970 and 9.7 x 106~3/ml in 1966. The average annual phytoplankton volume in the Northeastern end or Lake Ontario in 1970 was 2.5-3.5 x 106~3/ml, indicating that this area was not as productive as four other areas which exceeded 4.5 x 106~3/ml, (Munawar and Nauwerck 1971). Our 11 stations

159

PHYTOPLANKTON BIOMASS AND SPECIES COMPOSITION in 1965 showed a somewhat higher value of 5.42 x 106~3/ml. However, the 1970 survey appears to have included only 2-3 stations in the Northeastern end of Lake Ontario, whereas data presented here were based on 11 stations, many of these located in shallower, potentially more productive "inshore" areas. During the spring, phytoplankton maximum Bacillariophyta were the predominant group (Fig. 2), accounting for 45-98% of the total phytoplankton volume. The three most important taxa were Stephano-

discus hantzschii~ s. binderanus (Melosira binderanaJ and Asterionella formosa. In the summer

(July-September) flagellates (Divisions Chrysophyta~ Euglenophyta and Pyrrophyta) were m~st abundant, with Trachelomonas sp. and Cryptomonas erosa as the dominant species. Species of Glenodinium~ Gymnodinium and Peridinium were present in smaller numbers, but were responsible for more than 20% of the total phytoplankton volume. Chlorophyta were the next in importance, with Oocystis borgei as the main species. In November, diatoms were again dominant. Stephanodiscus astraea and S. niagarae were the most important species. Flagellates were the next in importance. Station 5 was an exception in that green algae were as abundant as diatoms. On an annual basis in 1970, at station 93, Munawar and Nauwerck (1971) reported diatoms predominating (-38% of total biomass) , closely followed by Cryptomonads (-22%), Cyanophyta (-20%) and Chlorophyta (-18%). During 1965 diatoms were also predominant, accounting for 53% of the total phytoplankton volume. Flagellates accounted for 28%, Chlorophyta for 13% and Cyanophyta for 5% of the

total phytoplankton volume.

Actinastrum hantzschii and Nitzschia holsatica reported by Nalewajko (1966) off Gibralter Point were not seen in the samples from the eastern end. However, many more species of flagellates and of Chlorophyta were present than previously reported. Species occurring only once or twice have not been included in Table 2. About 19 species were in this category. Certain delicate flagellates reported by Munawar and Nauwerck (1970) were not seen in our samples, probably as a result of deterioration during storage. However, several species of flagellates were well preserved. Trachelomonas sp. was a common flagellate at all stations. It was responsible for more than 20% of the volume among flagellates. This species was not reported by Munawar and Nauwerck (1970).

Stephanodiscus

hantzschii~

the most numer~cally abundant diatom in our samples, was reported by Munawar and Nauwerck (1971) as forming spring blooms in the plankton. Nalewajko (1966) reported S. astraea to be common in the plankton, but did not distinguish the variety minutula, one of the frequent taxa in our samples. Cyclotella atomus was present in several samples. This species has not been previously reported in the plankton. It was observed by Duthie and Sreenivasa (1972) in the sediment diatoms from the lake. The most common diatoms in the superficial sediments from the Northeastern end of Lake Ontario were species of Stephano-

discus. Rhizosolenia eriensis and Dinobryon sociale were seen only in spring samples. The former is reported (Stoermer and Yang, 1969) to occur in Lake

160

SREENIVASA and NALEWAJKO

Michigan in late spring and early fall. The latter is known to occur in cold water. In conclusion, on the basis of phytoplankton biomass, the Northeastern end of Lake Ontario in 1965 was highly eutrophic, since values for maximum plankton volume exceeded by far the value of 10 x 106~3/1 suggested as a cut-off point by

Vollenweider (1968). Both average annual values at all stations and maximum values at a single station in 1970 were lower than in 1965, an indication perhaps of a trend towards more oligotrophic conditions. However, because of yearly fluctuations and because fewer stations were sampled in 1970, a confirmation of this trend is necessary.

ACKNOWLEDGEMENTS This research was supported in part by a National Research Council grant to C. Nalewajko.

REFERENCES Anderson, D. V. and D. Clayton, 1959. Plankton in Lake Ontario. Onto Dept. Lands and Forests, Phys. Res. Note No.1, 7 p. Bellinger, E. G. 1974. A note on the use of algal sizes in estimates of population standing crops. Er. Phycol. J. 9, 157-161. Davis, C. C. 1954. A preliminary study of the plankton of the Cleveland Harbor area, Ohio. II. The distribution and quantity of the phytoplankton. Ecol. Monogr' 3 24, 321-347. Duthie, H. C. and Sreenivasa, M. R. 1972. The distribution of diatoms on the superficial sediments' of Lake Ontario. Froc. l5th Conf. Great Lakes Res' 3 Internat. Assoc. Great Lakes Res., 45-52. Lund, J. W. G. 1961. The periodicity of ~ algae in 3 English Lakes. Verh. Int. Ver. Limnol' 3 14, 147-154. Lund, J. W. G., C. Kipling and E. D. LeCren. 1958. The inverted microscope method of estimating algal numbers and the statistical basis of estimations by counting. Hydrobiologia 3 11, 143-170. International Lake Erie Water Pollution Board and International Lake Ontario-St. Lawrence River Water Pollution Board. 1969. Report to the International Joint Commission on the pollution of Lake Erie, Lake Ontario and the international section of the St. Lawrence River. Vol. 3, 124-139. McCombie, A. M. 1967. A recent study of the phytoplankton of the Bay of Quinte, 1963-1964. Froc. lOth Conf. Great Lakes Res' 3 Internat. Assoc. Great Lakes Res., 37-62. Munawar, M. and Nauwerck, A. 1971. The composition and horizontal distribution of phytoplankton in Lake Ontario during the year 1970. Proc. l4th Conf. Great Lakes Res' 3 Internat. Assoc. Great Lakes Res., 68~78. Michalski, M. F. P. 1968. Phytoplankton levels in Canadian near-offshore waters of the lower Great Lakes. Proc. llth Conf. Great Lakes Res' 3 Internat. Assoc. Great Lakes Res., 85-95.

PHYTOPLANKTON BIOMASS AND SPECIES COMPOSITION

161

Nalewajko, C. 1966. Composition of phytoplankton in surface waters of Lake Ontario. J. Fish. Res. Ed. Canada~ 23, 1715-1725. Nalewajko, C. 1966. Dry weight, ash and volume data for some freshwater planktonic algae. J. Fish. Res. Ed. Canada~ 23, 1285-1288. Nalewajko, C. 1967. Phytoplankton distribution in Lake Ontario. Proc. lOth Conf. Great Lakes Res.~ Internat. Assoc. Great Lakes Res., 63-69. Ogawa, R. E. 1969. Lake Ontario phytoplankton, September, 1964, p. 27-38. In Limnological Survey of Lake Ontario~ 1964. Great Lakes Fish. Corom. Tech. Rpt. No. 14. Reinwand, J. F. 1969. Planktonic diatoms of Lake Ontario, p. 19-26. In Limnological Survey of Lake Ontario~ 1964. Great Lakes Fish. Corom. Tech. Rpt. No. 14. Schenk, C. F. and R. E. Thompson. 1965. Long-term changes in water chemistry and abundance of plankton at a single sampling location in Lake Ontario. Proc. 8th Conf. Great Lakes Res.~ Univ. Michigan, Great Lakes Res. Div. Pub. No. 13, 197-208. Stoermer, E. F. and Yang, J. J. 1969. Plankton diatom assemblages in Lake Michigan. Special Report No. 47, Great Lakes Research Div., Univ. Mich., Ann Arbor, Mich. Tucker, A. 1948. The phytoplankton of the Bay of Quinte. Trans. Amer. Microsc. Soc.~ 67, 365-383. Utermohl, H. 1931. Neue Wege in der quantitativen Erfassung des Planktons. Verh. Intern. Ver. Limnol.~ 5, 567-596. Vollenweider, R. A. 1968. Scientific fundamentals of the eutrophication of lakes and flowing waters, with particular reference to nitrogen and phosphorus as factors in eutrophication. Organ. Econ. Coop. Dev. (Paris) Tech. Rep., DAS/CS1/68.27, p. 182.