Ecological Relations of Main Plankton Components in the Pelagial of Lake Peipsi (original) (raw)
Related papers
Phytoplankton of Lake Peipsi-Pihkva: species composition, biomass and seasonal dynamics
Hydrobiologia, 1996
With 33 years of phytoplankton quantitative studies carried out, a series of qualitative data with a length of over 80 years is at our disposal. About 500 algal species have been found in plankton by different researchers. In different seasons and years 35 main species (dominants and subdorninants) form 68-96 % of biomass in L. Pihkva (southern, more eutrophic part) and 60-97 % in L. Peipsi (northern, less eutrophic part). L. Lammijkv, connecting the two parts is similar to L. Pihkva in respect to phytoplankton and the trophic state. Diatoms and blue-green algae prevail in biomass, diatoms and green algae, in the species number. The oligo-mesotrophic Aulacoseira islandica (0. Muller) Sim. is characteristic of the cool period; A. granulata (Ehr.) Sim. and Stephanodiscus binderanus (Kutz.) Krieger prevail in summer and autumn, the latter being most abundant in the southern part. Gloeotrichia echinulata (J.S. Smith) P. Richter and AphanizomenonJlos-aquae (L.) Ralfs dominate in summer causing waterbloom. Phytoplankton has mostly three maxima in seasonal dynamics in L. Peipsi and two in L. Pihkva. Its average biomass in spring in different years has fluctuated in the range 5.616 and 6-12.7 g m-3, in summer 3.1-14.8 and 5.6-125 (10-20 in most cases); and in autumn 7-16.3 and 5.2-26 in the northern and southern parts, respectively. The dominant complex has not changed considerably since 1909; however, the distribution of dominant species in lake parts has become more even in the last decades. Periods of high biomass occurred in the first half of the 1960s and 1970s and in 1988-1994, of low biomass in 1981-1987. The first coincided, in general, with periods of low water level and high water temperature.
Marine Ecology Progress …, 1997
In t h~s study we estimated the amount and fate of phytoplankton primary product~on in the coastal zone of the Gulf of Gdansk, Poland, an area exposed to nutnent enrichment from the Vistuld R~v e r and nearby inunlcipal agglomeration The ~n v e s t i g a t~o n s were carned out at 2 sites d u r~n g 5 months in 1993 (February, April, May, August and October). A prolonged bloom pei-iod occurred in the coastal zone, as compared to the open Gulf and the open sea waters. From Aprll until October most values of gross primary production in the near-surface layer were in the range 100 to 500 m g C m-'' d 1 Phytoplankton net exudate release constituted on average 5 % of the gross prlmai-y production, total exudate release was estimated to be about 2 times h~gher. Bacterial production in the growth season was relatively low (the mean value l y~n g between 5 and 9 % of gloss primary production), nevertheless, the microbial community (bactena and protozoans) u t~l~z e d a large proportion of primary production (from about 50% in April and May to 16'%, in October). Usually direct protozoan grazing on phytoplankton exceeded bacterial uptake of the phytoplankton exudates. In winter, summer and autumn communlty respiration exceeded depth-averaged primary production, ~n d~c a t i n g that external energy sources (s e d~m e n t resuspension, allochthonous organic matter) play a substantial role in communlty metabol~sm.
Phytoplankton primary production in a eutrophic cooling water pond
Hydrobiologia, 1984
The seasonal variation of phytoplankton photosynthesis was measured with 14C-method in a warmed ice-free pond in central Finland. Simultaneously with in situ measurements the photosynthesis was also measured in an incubator with different water temperatures and constant light (ca. 16 W m 2). The total annual photosynthesis was 57.2 C m 2 a-1. The portion of the winter and spring production of the annual photosynthesis was 18.4%, that of the autumn production ws 17.4%. Thus 64.3% of the total annual phytoplankton photosynthesis occurred in the three summer months. The range of the daily integrated photosynthesis per unit area was 1.9 563 mg C m -2 d I. The photosynthetic rate per unit chlorophyll a varied in situ from 0.94 to 33.1 mg C (mg chl. a) -1 d 1. The highest value was measured in the beginning of July and the lowest in mid-January. The photosynthetic rate increased in situ exponentially with increasing water temperature. In the incubator the highest photosynthetic rate values were also found in July and August (at +20 ° C) when the phytoplankton population was increasing and the minimum values occurred after every diatom maximum both in spring and autumn. Light was a limiting factor for photosynthesis from September to Mid-January, low water temperature was a limiting factor from late January through May. The efficiency of the photosynthesis varied between 0.1 and 0.7% of P.A.R. According to the incubator experiments the Q ~0 values for the photosynthesis were 2.45 and 2.44 for the winter population between 1 and 10 ° C and for the summer population between 5 and 15 ° C, respectively, but the Ql0 values decreased at the higher temperatures. The main effect of the warm effluents on the yearly photosynthesis was the increase of production in spring months due to the lack of ice cover. However, the increase of total annual phytoplankton photosynthesis was only ca. 10-15%, because the water temperature was during the spring months below 10 ° C. Hydrobiologia 118, 267 274 (1984).
The fate of planktonic primary production
Limnology and Oceanography, 1985
The carbon dynamics of phytoplankton communities in six different lakes were investigated. In each lake carbon-specific rates of production (b) and loss (d) were highly correlated and closely balanced through most of the year. As a result carbon-specific growth rates were usually very low and carbon standing crop was relatively stable between sampling dates. Major fluctuations in algal biomass occurred only when the production-loss balance was significantly perturbed. The frequency of these perturbations and the seasonal variability of b and d differed between lakes. The most consistent pattern was found in the low altitude lakes of the temperate zone, where b and d were highest in summer and lowest in winter. Values were also low during the spring and fall mixing periods when perturbations in the production-loss balance caused major peaks in carbon standing crop. The fate of primary production varied significantly between lakes. In most of the lakes considered the majority of carbon fixation was consumed in metabolic processes. However, in Lake Wingra a large part of the production was apparently lost through grazing and sedimentation. Differences in the average values of b, d, and % metabolic loss between lakes appeared to depend on the combined loss rate due to sinking and grazing. These results suggest a general pattern of carbon dynamics similar to that found in steady state continuous cultures.
Freshwater Biology, 2001
1. The inter-and intra-annual changes in the biomass, elemental (carbon (C), nitrogen (N) and phosphorus (P)) and taxonomical composition of the phytoplankton in a high mountain lake in Spain were studied during 3 years with different physical (¯uctuating hydrological regime) and chemical conditions. The importance of internal and external sources of P to the phytoplankton was estimated as the amount of P supplied via zooplankton recycling (internal) or through ice-melting and atmospheric deposition (external). 2. Inter-annual differences in phytoplankton biomass were associated with temperature and total dissolved phosphorus. In 1995, phytoplankton biomass was positively correlated with total dissolved phosphorus. In contrast, the negative relationship between zooplankton and seston biomass (direct predatory effects) and the positive relationship between zooplankton P excretion and phytoplankton biomass in 1997 (indirect P-recycling effects), reinforces the primary role of zooplankton in regulating the total biomass of phytoplankton but, at the same time, encouraging its growth via P-recycling. 3. Year-to-year variations in seston C : P and N : P ratios exceeded intra-annual variations. The C : P and N : P ratios were high in 1995, indicating strong P limitation. In contrast, in 1996 and 1997, these ratios were low during ice-out (C : P < 100 and N : P < 10) and increased markedly as the season progressed. Atmospheric P load to the lake was responsible for the decline in C : P and N : P ratios. 4. Intra-annual variations in zooplankton stoichiometry were more pronounced than the overall differences between 1995 and 1996. Thus, the zooplankton N : P ratio ranged from 6.9 to 40.1 (mean 21.4) in 1995, and from 10.4 to 42.2 (mean 24.9) in 1996. The zooplankton N : P ratio tended to be low after ice-out, when the zooplankton community was dominated by copepod nauplii, and high towards mid-and late-season, when these were replaced by copepodites and adults. 5. In 1995, the minimum demands for P of phytoplankton were satis®ed by ice-melting, atmospheric loading and zooplankton recycling over 100%. In order of importance, atmospheric inputs (> 1000%), zooplankton recycling (9±542%), and ice-melting processes (0.37±5.16%) satis®ed the minimum demand for P of phytoplankton during 1996 and 1997. Although the effect of external forces was rather sporadic and unpredictable in comparison with biologically driven recycle processes, both may affect phytoplankton structure and elemental composition. 1017 6. We identi®ed three conceptual models representing the seasonal phosphorus¯ux among the major compartments of the pelagic zone. While ice-melting processes dominated the nutrient¯ow at the thaw, biologically driven processes such as zooplankton recycling became relevant as the season and zooplankton ontogeny progressed. The stochastic nature of P inputs associated with atmospheric events can promote rapid transitional changes between a community limited by internal recycling and one regulated by external load. 7. The elemental composition of the zooplankton explains changes in phytoplankton taxonomic and elemental composition. The elemental negative balance (seston N : P < zooplankton N : P, low N : P recycled) during the thaw, would promote a community dominated by species with a high demand for P (Cryptophyceae). The shift to an elemental positive balance (seston N : P > zooplankton N : P, high N : P recycled) in mid-season would skew the N : P ratio of the recycled nutrients, favouring dominance by chrysophytes. The return to negative balance, as a consequence of the ontogenetic increase in zooplankton N : P ratio and the external P inputs towards the end of the ice-free season, could alleviate the limitation of P and account for the appearance of other phytoplankton classes (Chlorophyceae or Dinophyceae).
Hydrobiologia, 2008
Data for the vegetation periods (May-November) of 1985-2003 were used to collate the nutrient content and biomass of the most important phytoplankton groups in Lake Peipsi (Estonia). Two periods differing in external nutrient load and water level were compared by analysis of variance. The years 1985-1988 were characterized by the highest loads of nitrogen and phosphorus, high water level and cool summers. The years 2000-2003 were distinguished by low or medium water levels and warm summers. The first period showed statistically significantly higher values of total nitrogen (N tot ) and a higher N tot :P tot mass ratio. The second period showed a higher content of total phosphorus (P tot ), a higher ratio of dissolved inorganic compounds N to P and higher phytoplankton and cyanobacterial biomasses. Comparison between parts of the lake demonstrated that the differences between the two periods were more evident in the shallower and strongly eutrophic parts, Lake Pihkva and Lake Lämmijärv, than in the largest and deepest part, the moderately eutrophic Lake Peipsi s.s. Temperature and water level acted synergistically and evidently influenced phytoplankton via nutrients, promoting internal loading when the water level was low and the temperature high. The effect of water level was stronger in the shallowest part, Lake Pihkva. The difference in P tot content between the southern and northern parts was twofold; the N tot :P tot mass ratio was significantly lower in the southern parts, and phytoplankton biomass (particularly the biomass of cyanobacteria) was significantly higher for Lake Pihkva and Lake Lämmijärv than for Lake Peipsi s.s.
International Review of Hydrobiology, 1998
An analysis of plankton seasonal succession in large shallow eutrophic lake Vdrtsjlrv (270 km', mean depth 2.8 m, max. depth 6 m) is presented. Weekly samples for 1995 have been analysed using the PEG model approach. In winter, light was the main factor controlling phytoplankton growth. In early spring phytoplankton was mainly resource-controlled, competition for phosphorus being the main driving force. Ciliates (Parudileptus sp., Strobilidiiim sp. and Vorricella sp.) were the first herbivores which started to increase in April causing a twofold decline of phytoplankton biomass. The annual maximum of primary production (PP) in early May was probably caused by soluble reactive phosphorus (SRP), regenerated by herbivores, and stirred up from bottom sediments as a result of strong wind stress. This primary production peak provided substrate for further increase of bacterial biom food supply supported the development of the second spring peak of herbivores nile copepods) which was followed by the second modest "clear water phase" in late May. Silicon was depleted by the end of May causing a strong decrease in primary production of the diatom-dominated community, whereas the biomass of the cyanophytes increased under the improved nutrient conditions. Some weeks later, inorganic N was depleted and the period of N limitation with the appearance of Nfixing cyanophytes began. The ciliate collapse at the beginning of June coincided with the start of the cladoceran development and with the increase of other metazooplankton groups. This explains the further decrease of the biomass of phytoplankton and bacteria in spite of their high production. Beginning from late June, silicon appeared again and SRP started to occur periodically, while inorganic N remained close to zero until November. During this period, phytoplankton development relied to a great extent on the N-fixation and N-regeneration potential. The collapse of the ciliate community in September removed the top-down control from bacteria and their biomass increased, while the development of cladocerans still suppressed phytoplankton biomass in spite of a quite high PP. In October phytoplankton biomass and chlorophyll o (Chlu) increased, SRP was completely depleted by the middle of October reflecting a slow regeneration due to the declined activity of zooplankton in cold water. In November nitrates appeared again, and silicon reached the same level as in spring. The biomass of N-fixing Aphcrnizornenon skitjae decreased while Limnorhrix redekei and L. plunctonica were quite abundant together with diatoms.
Phytoplankton, phytoplankton growth and biomass cycles in an unpolluted and in a polluted polar lake
Verhandlungen, 1975
With 6 figures and l table in the text Ultraoligotrophic Char Lake and sewage polluted Meretta Lake located near Resolute Bay, Canada (74° 42' N 94° 57' W) have been studied as one of Canada's contributions to the Intemational Biological Programme. The lakes and aspects of their primary production have been reported (KALFF et al. 1972; SCHINDLER et al. 1974 a, b; KALFF & WELCH 1974; WELCH & KALFF 1974). The purpose of the present paper is to compare the biomass and biomass cycles as well as community and some species growth rates in these two lakes, between May 1969 and February 1971.
Seasonal dynamics of primary production in the pelagic zone of southern Lake Baikal
Limnology, 2003
We measured primary production by phytoplankton in the south basin of Lake Baikal, Russia, by in situ 13C-bicarbonate incubations within the period March–October in two consecutive years (1999 and 2000). Primary production was highest in the subsurface layer, possibly due to near-surface photoinhibition of photosynthesis, even under 0.8 m of ice cover in March. Areal primary production varied from 79 mg C m−2 day−1 (March) to 424 mg C m−2 day−1 (August), and annual primary production was roughly estimated as 75 g C m−2 year−1, both of which are within the lower range of previous estimates. Size fractionation measurements revealed that phytoplankton in the Lake Baikal.