Phytoplankton Periodicity Research Articles

Limnological responses to changes in the thermal mixing regime in Lake Biwa associated with global warming

In Lake Biwa, restoration of water quality was achieved through the control of phosphorus discharges from the drainage basin. Recently, additional concerns have arisen regarding accelerating hypolimnetic deoxygenation and changes in the flora and seasonal periodicity of phytoplankton. Based on the analysis of the monitoring survey data, the effects of the changes in lake water mixing due to global warming on phytoplankton dynamics were examined using the seasonal [NO3] changes in surface water as a marker of the vertical mixing of water column. Autumnal increases in the surface water [NO3] started one month earlier after 1990. It was concluded that earlier onset of the fall overturn after 1990 was due to warming of the hypolimnion by warm winters after 1990. Because of diverse impacts of climate change and anthropogenic activities on lakes, and less predictability of their cumulative effects, increased knowledge of these effects is an urgent requirement for the progress of limnological science under global warming.

Phytoplankton dynamics and periodicity in two cascading warm-water reservoirs from 1989 to 1997 – taxonomic and functional (C-S-R) patterns, and determining factors

The composition and abundance of distinctive planktonic autotrophs (ca 60 taxa) were examined at roughly fortnightly intervals in two sizeable reservoirs (Midmar and Albert Falls) on the uMngeni River, KwaZulu-Natal, between 1989 and 1997. The dynamics of community structure and abundance were examined in both taxonomic and functional (C-S-R) terms in relation to physical abiotic variables (thermal stratification, light climate, water level) and biotic influences of predation (zooplankton abundance). Annual periodicity was exhibited by most taxa apart from Cryptomonas, although patterns tended to be indistinct and inter-annual repeatability was generally weak – in line with year-to-year and between-system environmental variability. Water level fluctuation, with concomitant change in stratification intensity and hydraulic mixing and accompanying changes in water clarity associated with suspended sediment levels was clearly a major (direct and indirect) determinant of phytoplankton composition and abundance. The influence of top-down controls as inferred from phytoplankton-zooplankton relationships was fundamentally different in the two reservoirs – potentially stimulatory in Midmar, but clearly regulatory in Albert Falls, where episodic collapses of Daphnia populations resulted in chlorophyll values well into the eutrophic level range. In addition to annual patterns, changes in chlorophyll content implied progressive long-term changes in trophic status, especially in Albert Falls, with the emergence of various ‘new' taxa (and/or higher peak densities of others). Consideration of phytoplankton dynamics in terms of functional groups offers certain advantages over conventional phyletic taxonomic analyses, although algal response forecasting by either approach appears potentially constrained by hydrological variability. Site-specific bio-monitoring, possibly using new rapid technologies, is likely to be necessary for ongoing management purposes until predictive capabilities under regionally characteristic conditions improve. Despite limitations, functional classification proffers faster advances to this end than conventional taxonomic appraisal. Water SA Vol 32(1)pp:81-92

Water quality and phytoplankton communities in Lake Qarun (Egypt)

Lake Qarun is a closed saline lake in the northern part of El-Fayoum Depression (Middle Egypt) at the margin of the Great Western Desert. It is almost entirely sustained by inflow from the Nile River and, during the 20th century, lake water salinity has increased strongly. Physico-chemical characteristics and phytoplankton periodicity in the lake were monitored during 2001. All the water quality variables measured showed considerable seasonal variation, and quantitative and qualitative differences in phytoplankton communities were recorded. The maximum crop density was in August, whereas lowest values occurred in December. Highest crop densities coincided with a high abundance of Bacillariophyceae. The Bacillariophyceae were most diverse with 23 species, then Chlorophyceae with 16, Cyanophyceae with 8, and Chrysphyceae and Dinophyceae with one species each. Despite being a saline inland lake, the open-water phytoplankton communities were composed of some marine/brackish forms but mainly of freshwater communities tolerant to high salinity. The identified phytoplankton species indicate a tendency towards eutrophy but total crop densities were relatively low compared with eutrophic lakes elsewhere. Light limitation by suspended solids as well as hydrological related factors are believed responsible for the relatively low phytoplankton abundance. The lake appears to be ecologically unstable and careful limnological monitoring is recommended.

Phytoplankton periodicity and sequences of dominance in an Amazonian flood-plain lake (Lago Batata, Pará, Brasil): responses to gradual environmental change

The composition of the phytoplankton of Lago Batata,a flood-plain lake connected to Rio Trombetas,undergoes a conspicuous annual cycle which is relatedto the hydrology (depth of water, rate of fluvialflushing) and the hydrography (stability, frequency ofmixing of the water) of the lake. From a sparsenanoplankton at high-water and high flushing, the lakepasses to desmid-diatom dominance and finally tofilamentous cyanobacteria when the lake is barely 2 mdeep. As it refills, the lake again becomes desmid-dominated; then, when the turbidity is least and thestratification most stable, Botryococcus becomesa major component. Eventually flushing becomes toorapid for any but the relatively fastest-growingspecies. These changes are gradual and, at the scaleof algal generation times, cannot be explained assharp or sudden disturbances. Neither do they have theproperties of ecological successions but ratherrepresent compositional responses to a progressiveenvironmental modification analogous to the floristicphenomenon of gradual climate change.

The phytoplankton periodicities of two warm-climate lakes subject to marked seasonal variability

ABSTRACTThe phytoplankton periodicity of a tropical upland reservoir in Nigeria (Liberty Dam, Jos Plateau) and a temperate-type lake (L. Naranbagh) from the Kashmir Himalaya were compared. Variations in the phytoplankton communities in the water-bodies were both quantitative and qualitative. Liberty Dam conformed to the oligotrophic-desmid plankton type whilst in L.Naranbagh, phytoplankton resembled the eutrophic chlorococcales-diatom plankton type. Contrary to the general belief of muted (or lack of) seasonal changes in tropical regions, phytoplankton succession in the Jos reservoir was pronounced with dense persistence of some species for relatively short periods. The most striking fluctuations, typical of many temperate waters, were characteristic of L. Naranbagh with a build-up of plankton during summer and autumn. Variability in photosynthetic productivity was related to shifts in the climate-dependent population densities. The seasonal growth of the Jos phytoplankton reflected the alteration from the dry ‘Harmattan’ (December–February) to wetter (May–September) periods. These are analogous to the winter (December–February) and summer (June–August) seasons of the Kashmir Himalayan Valley. Phytoplankton associations and periodicities in each of the two warm-belt lakes were strongly driven by their respective local environments, including especially the marked seasonality of the climatic variables (rain, wind and solar radiation). Detailed comparisons of adequate long-term data from tropical and temperate waters are still required.

Phytoplankton Periodicity in a Eutrophic Coastal Water of the Baltic Sea

AbstractThe phytoplankton periodicity in the Darss‐Zingst bodden chain, an estuary‐like coastal water of the southern Baltic Sea, was investigated from 1984 to 1990. The following functional groups were established: 1.) nitrogen‐fixing Cyanobacteria plus Oscillatoria limnetica, 2.) coccoid Chlorophyceae, Gomphosphaeria pusilla, Lyngbya contorta and Stephanodiscus hantzschii, 3.) coccoid Cyanobacteria except Gomphosphaeria, 4.) diatoms except Stephanodiscus, 5.) Cryptophyceae and some other flagellates.A general seasonal pattern was observable: in cold winters group 5 dominates; in spring a diatom bloom (= group 4) occurred, which was followed by the development of group 2; steep temperature increases caused a summer bloom of nitrogen‐fixing cyanobacteria (= group 1), which was followed by groups 2 and 3 in autumn; in bland winters group 2 lasts until spring.Grazing was shown to be of minor importance for the phytoplankton periodicity.

Phytoplankton periodicity in Ogelube Lake, Anambra State, Nigeria during 1979?1980

Ogelube is a tropical oligotrophic lake having a desmid dominated phytoplankton with maximum density during the warmest season. During the rainy season, the lake cools, phytoplankton declines and dominance shifts to algae other than desmids. The lake cools further as harmattan advances, while phytoplankton reaches its minimum, suggesting water temperature to be more important than other environmental conditions. Decrease in phytoplankton density with falling water temperature was probably due to slower reproduction, rather than to increased death rate.

Seasonal Periodicity in Lacustrine Phytoplankton and the Theory of Ecological Succession

AbstractAn attempt has been made to examine the extent to which seasonal periodicity of lacustrine phytoplankton corresponds to the general concepts of the theory of ecological succession. The study was carried out on an eutrophic lake (Aydat, France). As REYNOLDS (1980, 1984) suggests, the seasonal periodicity of phytoplankton is an autogenic succession which may be perturbed by allogenic physical processes that change the initial direction of the succession. Thus, in this lake, only spring succession of phytoplankton can be considered as a true succession, consistent with the theory of ecological succession in that it was a directional and predictable phenomenon leading to an increasing complexity of community.

Heavy metal pollution and phytoplankton in the river Moosi (Hyderabad), India

Heavy metal pollution and its impact on the distribution and periodicity of phytoplankton in the river Moosi has been investigated continuously for a year at two highly polluted sites. The metals are in the order of Fe > Zn > Pb > Mn > Co > Cu > Ni and the different groups of algae are in the sequence of — Chlorophyceae > Bacillariophyceae > Cyanophyceae > Euglenophyceae. Green algae are more tolerant to the metals. Certain planktonic species serve as indicators of heavy metal pollution.

The concept of ecological succession applied to seasonal periodicity of freshwater phytoplankton

(1988). The concept of ecological succession applied to seasonal periodicity of freshwater phytoplankton. SIL Proceedings, 1922-2010: Vol. 23, No. 2, pp. 683-691.

Phytoplankton Analysis in Lake Sat Tal (U.P.), India

AbstractSpecies composition and periodicity of phytoplankton were studied in relation to various physico‐chemical parameters over a period of 18 months in the two basins of Lake Sat Tal. Taxonomic analysis led to 54 species. Phytoplankton density in the euphotic zone ranged from 0.33 × 105 to 4.12 × 105 cells I‐1 in the western basin (WB) and 1.31 × 105 to 6.05 × 105 cells I‐1 in the eastern basin (EB). The dinoflagellates (Peridinium willei, P. cinctum, Gymnodinium fuscum) which were relatively insignificant concerning number reached very high values concerning biomass, contributing 89 % and 92 %, respectively, to the total phytoplankton standing stock. Various factors as rainfall, light, temperature, organic matter, nutrients (particularly PO4‐P), silicate, were observed to play an important role in the periodicity of phytoplankton. Similarity coefficients revealed that the algal population was not very homogenous all the year round with similarities between consecutive samples ranging from 16 % to 77 % in WB and 21 % to 76 % in EB.

The periodicity of phytoplankton in Lake Constance (Bodensee) in comparison to other deep lakes of central Europe

Phytoplankton periodicity has been fairly regular during the years 1979 to 1982 in Lake Constance. Algal mass growth starts with the vernal onset of stratification; Cryptophyceae and small centric diatoms are the dominant algae of the spring bloom. In June grazing by zooplankton leads to a ‘clear-water phase’ dominated by Cryptophyceae. Algal summer growth starts under nutrient-saturated conditions with a dominance of Cryptomonas spp. and Pandorina morum. Depletion of soluble reactive phosphorus is followed by a dominance of pennate and filamentous centric diatoms, which are replaced by Ceratium hirundinella when dissolved silicate becomes depleted. Under calm conditions there is a diverse late-summer plankton dominated by Cyanophyceae and Dinobryon spp.; more turbulent conditions and silicon resupply enable a second summer diatom growth phase in August. The autumnal development leads from a Mougeotia — desmid assemblage to a diatom plankton in late autumn and winter.

Phytoplankton periodicity of the Waitaki Lakes, New Zealand

Phytoplankton periodicity of the Waitaki Lakes, New Zealand

Experimental manipulations of the phytoplankton periodicity in large limnetic enclosures in Blelham Tarn, English Lake District

This paper reviews the results of experimental manipulations, carried out during the period 1977–1983, on the phytoplankton maintained in the limnetic enclosures at Blelham Tarn, English Lake District. Three categories of manipulations are considered. The effects of variation in the scale and frequency of phosphorus loading (range: 0.3 to 2.5 g P m−2 a−1) upon the mean phytoplankton biomass, its seasonal distribution and specific dominance are shown to conform to well-established patterns and relationships observed in natural lakes. Much of the seasonal variability in species dominance occurred independently of nutrient ratios, though carbon availability has been critical at times. Attempts to manipulate the rates of removal of phytoplankton by grazing have confirmed that they act selectively against certain smaller species only, that they alter the rate of successional change, rather than its direction, and that they have little lasting influence upon the total phytoplankton standing crop. Attempts to manipulate rates of sinking loss through artificial enlargement of the epilimnetic circulation also regulated the light-conditions experienced by suspended phytoplankton. Growth-rate relationships to an index of light exposure and to temperature fluctuation are also derived for several species and are related to morphological and physiological characters of the organisms concerned. These interpretations are briefly reviewed in relation to periodic cycles in natural lakes.

Phytoplankton Periodicity in an Urban Lake: Summit Lake, Akron, Ohio (USA)

ABSTRACT Summit Lake, a small (37.4 ha), shallow (Zm = 13 m), hypertrophic, and normally dimictic lake, received inflowing heated water in mid-June 1977 partly disrupting thermal stratification. The water column was well-mixed to depths 4–5 X the depth of the photic zone (2–2.5 m). Phytoplankton cell volumes ranged from 1 mm3/L in late winter to 100 mm3/L in spring, averaging 12 mm3/L following destratification. A prominent autumnal phytoplankton maximum failed to develop. One hundred thirty-two (132) species of phytoplankton were identified. A prominent spring peak of cyanobacteria, green algae, and diatoms was followed by predominantly non-heterocystous cyanobacteria, Oscillatoria prolifica, Microcystis aeruginosa, and Gomphosphaeria lacustris. The dominance of cyanobacteria can be attributed to their ability to maintain buoyancy and to conditions favoring their growth—e.g. a turbid photic zone with high levels of phosphorus and ammonia probably derived from sanitary sewage inflows.

The atypical seasonality of phytoplankton in Crose Mere, 1972: an independent test of the hypothesis that variability in the physical environment regulates community dynamics and structure

Unusual features of the seasonal periodicity of phytoplankton in Crose Mere, 1972, included the extended phase of vernal diatom dominance, the development of spring populations of Pediastrum and Closterium, a large June maximum of Eudorina and a large August maximum of Volvox. With respect to temperature, thermal stability and light availability in the water column, the specific growth responses detected in 1972 are shown to be strongly consistent with those in other years and in other lakes, yet the interspecific differences are preserved. The atypical seasonality of plankton observed in 1972 was brought about by the atypical sequence of atmospheric conditions that, in turn, modified the temporal phasing and subsequent stability of thermal stratification. These events demonstrate the importance of phytoplankton responses to physical variability of the environment.

Phytoplankton periodicity of the Waitaki lakes, New Zealand

The Waitaki River system in the South Island of New Zealand includes three large glacially-formed headwater lakes, Tekapo, Pukaki and Ohau, which drain into the manmade Lake Benmore. Phytoplankton periodicity was followed from December 1975 to January 1980 as part of a study investigating possible changes in these lakes as a consequence of hydroelectric development. The phytoplankton was highly dominated by diatoms, e.g., Diatoma elongatum, Cyclotella stelligera, Asterionella formosa, and Synedra acus, but in lakes Ohau and Benmore populations of green algae occasionally developed. In all four lakes seasonal phytoplankton periodicity was observed with maximum biomass in spring and summer. In Lake Tekapo, the first lake in the chain, maximum biomass did not exceed 300 mg m-3, but in the very turbid Lake Pukaki the maximum summer biomass ranged between 300 and 800 mg m-3. In Lake Ohau, the least turbid lake, maximum biomass was around 1 000 mg m-3. In the newly created Lake Benmore periodicity was less evident and summer maxima reached over 1 500 mg m-3. The phytoplankton periodicity in these lakes is greatly influenced by seasonal patterns of turbidity from inflowing glacial silt.

The periodicity of phytoplankton in Lake Constance in comparison to other deep lakes of Central Europe

The periodicity of phytoplankton in Lake Constance in comparison to other deep lakes of Central Europe

Phytoplankton periodicity: the interactions of form, function and environmental variability

SUMMARY. 1. This review considers the periodic cycles of species dominance in a wide selection of temperate lakes. By ascribing individual species to assemblages, a high incidence of similarity among periodic cycles is demonstrated. Reference to lakes at high and low latitudes, as well as to rivers, shows conformity to parts of the same broad patterns.2. The role of population dynamics in shaping community structure is emphasized. Two types of change are recognized: autogenic, undirectional subsequences (successions), regulated by specific responses to critically changing resource‐ratio gradients; and allogenic changes, regulated by variability in the physical environment.3. Analysis of the responses of representative species to allogenic change permits further grouping of the assemblages. These groupings coincide with clear morphological distinctions among the same phytoplankton species according to their unit sizes and surface area/volume ratios.4. It is argued that these properties condition the physiological responses of algae to seasonal variations in temperature, mixing and exposure to the underwater light field. The responses are compounded by relative resistances to loss processes (sinking, grazing), by short‐term photosynthetic adaptation and vertical migratory behaviour.5. Graphical summaries are presented that relate the morphologically‐, physiologically‐ and behaviourally‐mediated responses to a hierarchy of physical, chemical and biotic environmental variables. Phytoplankton periodicity is the outcome of these interactions.

Relationships between phytoplankton periodicity and the concentrations of total and unionized ammonia in channel catfish ponds

Phytoplankton abundance fluctuated throughout a 9 month study period in two 1.62 ha channel catfish (Ictalurus punctatus) production ponds. Summer phytoplankton communities in both ponds were dominated by blue-green algae (Cyanophyta). During periods of rapidly decreasing phytoplankton abundance, total ammonia-nitrogen concentrations increased but a decrease in pH during these same periods moderated the concentrations of unionized ammonia-nitrogen. Although unionized ammonia-nitrogen concentrations did not reach levels considered acutely toxic to fish, extended periods of moderately high unionized ammonia-nitrogen concentrations (>O.15 mg/1) occurred in the late fall months and may have serious implications for fish health.