The phytoplankton of the internal Gulf of Olbia (North-East Sardinia) between July 1992 and July 1993

Abstract

The density variations and phytoplankton structure of the internal Gulf of Olbia (north-east Sardinia) from July 1992 to July 1993 are described.

The most important class was the Bacillariophyceae, because it accounted for the maximum values and because it dominated over about one-third of the study cycle. The picoplankton was present practically all the year round with the greatest development from September to March. Prymnesiophyceae, Dinophyceae, Cyanophyceae and Euglenophyceae were found more numerously in summer and autumn 1992 than in the rest of the year, while Bacillariophyceae, Chlorophyceae and Chrysophyceae were mostly found in spring and summer 1993.

Among the 16 species that expressed the highest mean yearly density values (greater than 1×10⁴ cell I^-1), 10 were Bacillariophyceae, 2 Dinophyceae, 3 Chrysophyceae and 1 Chlorophycea. The Bacillariophyceae have also been the dominant class in floristic terms (49 taxa on 95 total), followed by the Dinophyceae (26), the Chlorophyceae (5), the Chrysophyceae (5), the Prymnesiophyceae (4), the Prasinophyceae (2), the Euglenophyceae (2) and the Cyanophyceae (2).     

Phytoplankton biodiversity in the two perennial lakes of Coimbatore,Tamil Nadu,India

The present study was focused to evaluate the phytoplankton biodiversity in two freshwater perennial lakes of Sulur and Ukkadam of Coimbatore District, Tamil Nadu, India. The study period was two years from March 2012 to February 2014. Results revealed that totally 50 species of phytoplankton include 14 Cyanophyceae, 19 Chlorophyceae, 14 Bacillariophyceae, and 3 Euglenophyceae were recorded from the Sulur lake and 36 species of phytoplankton comprising 9 species of Cyanophyceae, 15 species of Chlorophyceae, 10 species of Bacillariophyceae and 2 species of Euglenophyceae were noticed in Ukkadam lake during the study period. The recorded phytoplankton density was ranged between 22,380 and 80,590 cells/l in Sulur lake and 29,350 and 1,16,255 cells/l in Ukkadam lake. Thus, the present study overall dominance of phytoplankton group was Chlorophyceae followed by Cyanophyceae, Bacillariophyceae, and Euglenophyceae. The phytoplankton population was recorded maximum in Ukkadam lake when compared to Sulur lake. Hence, the study revealed that both Ukkadam and Sulur lakes possess an appreciable quantum of phytoplankton and it can be used for fish culture.     

Limnology of a Sewage Polluted Lake: The Lower Lake (Bhopal,India)

Seasonal and vertical distribution of temperature, pH, dissolved oxygen, free CO₂, alkalinity, nitrate, phosphate and phytoplankton have been studied at the deepest point of the Lower Lake, Bhopal from September 1979 to August 1981. Stratification was noticed in almost all the parameters. Bottom was frequently anoxic. The dominant groups among phytoplankton were Chlorophyceae, Cyanophyceae and Bacillariophyceae.     

Phytoplankton communities of North African wetland lakes: the CASSARINA Project

Seasonal variations in phytoplankton species composition (frequencies) and densities (cell numbers) in nine North African coastal lakes selected in Morocco (Merja Sidi Bou Rhaba, Zerga and Bokka), Tunisia (Chitane, Ichkeul and Korba lakes) and Egypt (Edku, Burullus and Manzala lakes) were investigated during 1998. The main aim was to provide gase-line information about overall phytoplankton diversity and how phytoplanktoncharacteristics differ between these contrasting aquatic systems.Water samples were collected at approximately three monthly intervals and phytoplankton analysis revealed marked seasonal and spatial differences in the quantitative and qualitative composition of the communities at each site. The Egyptian lakes generally had larger crops (Manzala and Burullus had mean crop densities of more than 104 cells ml^–1) but in the western North African sites only Korba and Sidi Bou Rhaba had closely comparable densities. Algae belonging to Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cyanophyceae, Dinophyceae and Euglenophyceae were recorded. Taxa representative of all these algal groups occurred in two lakes (Korba and Manzala) but at the other seven sites only some of the groups were present.The Chlorophyceae was the most dominant group in lakes Burullus, Manzala, Korba and Sidi Bou Rhaba whereas Bacillariophyceae were dominant in lakes Zerga, Bokka and Edku. In Ichkeul and acidic Chitane the Dinophyceae and the Cyanophyceae were the dominant groups, respectively. The maximum percentage of Euglenophyceae occurred in Edku Lake but this group was absent in Sidi Bou Rhaba and Ichkeul. Cyanophyceans were present in significant numbers in all investigated lakes except in Ichkeul. A total of fifty-three genera were recorded, 17 of Chlorophyceae, 18 of Bacillariophyceae, 11 of Cyanophyceae, 3 of Chrysophyceae, 2 of Euglenophyceae and 2 of Dinophyceae. The maximum number of species (34) occurred in Burullus Lake and the minimum (6) in Ichkeul Lake. Only one lake (acidic Chitane) possessed species indicative of oligotrophic conditions. The Nile Delta lakes were the most species diverse sites.The phytoplankton communities of the nine North African lakes were composed entirely of cosmopolitan species but with one new species (Cyclotella choctawatcheeana) was recorded for the region. The data presented provide a contemporary account of the levels of algal diversity present in these sites at the end of the 20th century. The relevance of phytoplankton communities to assessment of lake status and future monitoring studies in the region is emphasised.     

Limnological Studies on the River Tigris,Iraq. III. Phytoplankton

Variations in quantity and structure of phytoplankton in the lower 630 km stretch of the Tigris were studied and discussed. The Chlorophyceae generally contributed more genera to the phytoplankton community, and the Bacillariophyceae and Cyanophyceae ranked second and third, respectively. The phytoplankton generally showed considerable local and seasonal variations at the surfaces of the sampling locations.     

Studies on the gut contents of leptestheriella maduraiensis (Conchostraca: Branchiopoda) Nayar and Nair

Studies on the food and feeding habits of Leptestheriella maduraiensis Nayar & Nair have shown that the organisms are nonselective algal and detrital filter feeders. They utilise available food in almost similar proportions as in the overlying pond water and it is found from the present studies that the phytoplankton (Bacillariophyceae, Chlorophyceae and Cyanophyceae) form the major part of the gut (48.9%), followed by detritus (38.6%), zooplankton (11.1%) and miscellaneous items (1 .4%).Formed part of a thesis approved for the degree of Ph.D. of the Madurai University, 1973.Formed part of a thesis approved for the degree of Ph.D. of the Madurai University, 1973.     

Salinity gradient and nutrients as major structuring factors of the phytoplankton communities in salt marshes

This study investigated the major environmental factors structuring, for a year, phytoplankton assemblages in the Sfax saltern (Tunisia): salinity and nutrients. A STATICO analysis based on 11 environmental variables and the abundances of 64 phytoplanktonic species was conducted. STATICO is used to analyze the stable part of the relationships between the environment and species, and then to determine how these relationships change over time. The analysis confirmed that the salinity gradient had a considerable influence on the composition of the phytoplanktonic communities. Bacillariophyceae and Dinophyceae dominated in the least salty ponds, whereas Chlorophyceae and Cyanophyceae dominated in the saltiest ponds, in accordance with the halotolerance level estimated for each species by calculating the optimum salinity and salt tolerance. Nitrogen (N) and phosphorus (P) ions could have a secondary influence on the phytoplankton distribution and its dynamics. Dinophyceae seem to be favored by high ammonium (NH₄ ⁺) concentrations, whereas diatoms seem to be favored by high orthophosphates (PO₄ ^3?) and nitrates (NO₃ ^?) values. The Chlorophyceae Dunalliela salina thrived in the saltiest ponds when the NO₃ ^? concentrations increased.     

Flood pulse influence on phytoplankton communities of the south Pantanal floodplain, Brazil

Four sites situated on the Pantanal floodplain (Paraguay River and floodplain) were sampled throughout the annual cycle, mainly during the rising water period, with the aim of evaluating the effects of the flood pulse on the composition and population densities of the phytoplanktonic communities. Comprehensive water chemistry data were collected. Eighty-two taxa were found, numerically dominated by Chlorophyceae (23 taxa). Cryptophyceae (principally Cryptomonas brasiliensis) occurred in all samples, and were responsible for 47–58% of the phytoplankton abundance in the studied area. Highest phytoplanktonic population density was at the rising water period, when the limnological changes are most marked as the river water first enters into contact with the floodplain. During this period, when intense decomposition occurs, the Cryptophyceae decreased and the Euglenophyceae increased, except at site 1 (Castelo Lake), where this group were more stable during the year, representing 35–56% of the phytoplankton. In the falling water period (September and October), the phytoplankton was also represented by Bacillariophyceae and Cyanophyceae. In the Pantanal, the great abundance and sometimes dominance of Cryptophyceae, may be due largely to adverse conditions for the development of other groups; the former are adapted to low availability of dissolved nutrients, and high water transparency, such conditions prevailing during the high water period.     

Assessment distribution of the phytoplankton community structure at the fishing ground,Banyuasin estuary,Indonesia

The research objective was to describe the distribution of phytoplankton community structure and corelated to the physic-chemical parameters at fishing ground, Banyuasin estuarine waters. The methodology of research was phytoplankton sampling; physicochemical waters parameters data collected such as; dissolved oxygen, pH, temperature, brightness, salinity, current speed, nitrate, and phosphate. Identifications and calculations phytoplankton are based on photography under a light microscope. Data were analyzed by calculated abundance, diversity (H′ index) and dominance (C index), and Principal Component Analysis (PCA). There were 24 species of phytoplankton on the all-observation station grouped in three classes, Bacillariophyceae 91.3%, Dinophyceae 9%, and Cyanophyceae 0.1%. The abundance of phytoplankton species obtained in the range of 666.48 to 184,592.68 cells L^?1, were mostly found in high Chaetoceros affinis and Bacteriastrum furcatum. The distribution of phytoplankton abundance in these waters was found to be more influenced by seawater mass than freshwater. Phytoplankton diversity is considered a moderate category (1.37 < H′ < 2.57), and there were no species of phytoplankton that dominates (C < 0.5). Principal component analyzes showed that waters can be classified based on their physical-chemical characteristics, which were temperature, salinity, pH, transparency, current speed in the south coast around river estuaries, while DO and nutrients on the north coast of the waters. Based on the distribution of phytoplankton abundance is illustrated that the northern part is more potential for fishing area than the southern part with an abundance of phytoplankton >90,000 cells L^?1 and more stable water dynamics.     

Temporal fluctuations of the phytoplankton community of the Baía River, in the upper Paraná River floodplain, Mato Grosso do Sul, Brazil

Subsurface samples were taken monthly (March/1993 through February/1994) in the Baía River, a tributary of the right bank of the Paraná River (22° 43 S and 53° 17 W). We analyzed temporal changes in the phytoplankton community in relation to density, biomass, richness and species diversity, equitability, size structure, and dominance. We related these to regional climate and hydrology, and to the physical and chemical variables of the water column. We determined 119 taxa, wich were numerically dominated by the class Chlorophyceae with 37 taxa. The classes Cyanophyceae and Bacillariophyceae contributed the most abundant biomass and were responsible for the two peaks that were observed. The high water period was generally characterized by lower phytoplankton biomass, higher richness and species diversity, and higher density of nannoplanktonic species such as Monoraphidium tortile in March, and Cryptomonas brasiliensis in January. During low water, however, the highest values of phytoplankton biomass were recorded, with heterocytous cyanophytes dominating during the phase of greater stability of the water column, and filamentous diatoms during periods of mixing turbulence. The fluctuations observed indicate that the hydrosedimentological regime of the Paraná River, together with the climatological factors, constitute the main forcing functions acting on the Baía River phytoplankton.     

Effect of fluctuations in water level on phytoplankton development in three lakes of the Paraná river floodplain (Argentina)

The effect of fluctuations in water level on phytoplankton development (abundance, biomass, size structure, taxonomic composition, species diversity and rate of community compositional change) in three vegetated lakes of the Paraná River floodplain (27° 27′?S; 58° 55′?W) were studied. Between September 1995 and June 1996 there were two inputs of lotic water. Ordering of physical and chemical parameters (Principal Component Analysis) allowed the differentiation of two phases: I) without lotic influence (limnophase) and II) with lotic influence (potamophase). Two-hundred fifty-eight algal taxa were identified, of which Euglenophyceae showed the highest number of taxa (65% of total). Small Chlorophyceae and Cryptophyceae (C-strategists) predominated in density in both periods. During potamophase, the input of nutrients from a flood event produced an increase in algal biomass and a shift in phytoplankton composition from a Chlorophyceae (C-strategists), to a Cyanophyceae and Euglenophyceae (S-strategists), dominated comunity. Bacillariophyceae, Chrysophyceae, Dinophyceae and Xanthophyceae were best represented during limnophase. All phytoplankton attributes showed significant differences between phases (limnophase vs potamophase) but not among lakes. These results support the hypothesis that hydrology (floods) clearly exerts an overall impact on the phytoplankton community composition in lakes of the Paraná River floodplain. Hydrology effects the lake water chemistry, conditioned by the isolation time prior to a flood, the horizontal dragging and exchange of algae during floods, and the water residence time and aquatic vegetation coverage.     

Polyphenolics and Energy Content in Phytoplankton: Evidence from a Freshwater Lake

Investigation was carried out in the ancient man-made, shallow, freshwater lake, Lake Krishnasayer, at Burdwan (23°16′N, 87°54′E), India, to note the variations in physico-chemical parameters, nutrients, phytoplankton communities, concentration of phenols and energy content in phytoplanktons during January–December 2006. The lake was represented by 16, 15, 2 and 17 genera of Cyanophyceae, Chlorophyceae, Euglenophyceae and Bacillariophyceae, respectively with significant variation in relative abundance as was revealed through Discriminant Analysis. Wilk’s λ values indicate that nitrate, phosphate, dissolved chlorides and silica, and phenol content were significant (P < 0.05) predictor for such differences. PCA analysis yielded three components explaining more than 68 % of the variations in the data on physico-chemical parameters, nutrients, phenol concentration and energy content of total phytoplankton. The interactions of the environmental variables contribute significantly to the observed variations in the phenol and energy content of the phytoplankton. However, the phenomenon of temporal variation in the total phytoplankton and energy content is accounted as a function of nitrate, phosphate-phosphorous, silicate and organic carbon levels. It is apparent that this quality of phytoplanktons varied with the seasons and thereby influencing the amount of phenol and energy content in the engulfing phytoplanktons. Therefore, adequate allocation is needed regarding nutritional status of phytoplanktons, in respect to the dietary need of aquaculture programme in practice.     

Influence of atypical pluviosity on phytoplankton assemblages in a stretch of a large sub-tropical river (Brazil)

This study aimed to evaluate the influence of alterations in pluviosity and ecological variables on microphytoplankton (> 20 μm) structure (composition, richness, diversity, and abundance) and its biomass (chlorophyll-a), comparing different regions in a stretch of the low Iguaçu River and in some tributaries. Phytoplankton was sampled in 10 stations (5 in Iguaçu River and 5 in tributaries) during a dry period (April/2004) and an atypical rainy period (June/2004). The conductivity showed significant difference among the sampling points. Temperature, dissolved oxygen, pH, silicate, and nitrate showed significant differences between the dry and wet periods. Phytoplankton was composed of 149 taxa, and the most representative class was Chlorophyceae (71 taxa), followed by Bacillariophyceae (35 taxa), and Cyanophyceae (25 taxa). During the rainy period, stations of Iguaçu River showed higher taxa number and total density compared to the tributaries, but the values were similar in the dry period. Tributaries presented higher diversity and equitability in both periods. Except by two stations in Iguaçu River, the higher taxa number, densities and biomass occurred in the dry period, associated to low levels of suspended matter. The canonical correspondence analysis indicated the dominance of Bacillariophyceae and Chrysophyceae in the rainy period related to nitrate and suspended matter. Two other groups were observed in the dry period: one formed by Cyanophyceae, Dinophyceae, and Rhodophyceae, related to temperature and nitrite and other by Euglenophyceae and Chlorophyceae related to total phosphorus and silicate. The groups suggest adequate conditions of the physical, chemical and climatic factors to the establishment of the algae classes. Phytoplanktonic assemblages responded quickly to the environmental regional variations under strong influence of pluviosity, while in the dry period, homogeneity among stations and environmental variables was observed. The importance of climatic events is relevant in ecological studies in a temporal scale.     

Algicidal properties of Acacia nilotica

The algicidal activity of aqeuous extracts of the pods of Acacia nilotica (L.) Willd. ex Del. was tested in artificial ponds. Algae belonging to the genera Rivularia, Oscillatoria, Spirulina, Chroococcus, Microcystis (Cyanophyceae), Pediastrum, Coelastrum (Chlorophyceae), Spirogyra, Cosmarium, Closterium (Conjugophyceae), Euglena (Euglenophyceae) and Cyclotella (Bacillariophyceae) were successfully controlled with this extract.     

Size‐selective feeding on phytoplankton by two morpho‐groups of the small freshwater fish Amblypharyngodon mola

Two morpho‐groups (i.e. small, MGS and big, MGL) of the small freshwater fish Amblypharyngodon mola were studied for their feeding behaviour in the natural environment. Both the morpho‐groups fed on a variety of phytoplankton including Cyanophyceae, Chlorophyceae, Bacillariophyceae and Euglenophyceae. The fish had more Chlorophyceae and Bacillariophyceae in their gut than other phytoplankton. Costello's selectivity plots revealed that the MGS fed on the smaller phytoplankters (2–6 µm in size), whereas the MGL fed on both the small and large (up to 12 µm in size) phytoplankters. The differences in mouth areas between the two morpho‐groups were explained as a possible reason of size‐selective feeding and contribute to overcome gape limitation in A. mola. This is further accompanied by the uniform pore size of the gills (2 µm) in all the morpho‐groups. This study concluded that A. mola exhibits a size‐dependent feeding strategy regulated by gape limitation at the ingestion level. With ontogenetic shifts, flexibility appears to overcome such a limitation in the MGL, having a wider mouth area supported by jaw opening ability.     

Abundance of algal species in relation to soil types and major crops in cultivated soils of Karnataka state (India)

Summary An attempt was made to study the number of species belonging to Cyanophyceae, Chlorophyceae and Bacillariophyceae in Lateritic, Red and Black soils and also Dry lands (jowar, cotton and wheat) and Wet lands (paddy and sugar cane). Lateritic and black soils had a poor algal flora and in general sandy soils were rich. Cyanophyceae appeared to be more resistant than Chlorophyceae and Bacillariophyceae to desiccation. Part of the Ph.D. Thesis approved by the Karnatak University (1976).     

Le phytoplancton des étangs de Berre et Vaïne (Méditerranée Nord-occidentale)

Phytoplankton of the Etang de Berre and Etang de Vaïne (N.W. Mediterranean) The phytoplankton in the brackish Etang de Berre and Etang de Vaïne was studied regularly at 12 stations for two years. The recent diversion of the Durance River into the Etang de Berre has effected a fundamental change in this formerly marine environment, which has had a great impact on its plankton populations. A total of 182 taxa were identified, including 111 Bacillariophyceae, 44 Chlorophyceae, and 15 Cyanophyceae. The most abundant species are small freshwater algae, mainly Chlorophyceae, since the salinity is generally less than 3 0/00. However, during summer and fall, as well as in waters near the bottom, the salinity can reach 15 0/00 and marine diatoms are predominant. Because the nutrients in the environment are constantly replenished, phytoplankters are always numerous, ranging in abundance between several million to several hundred million per liter. There is a somewhat irregular seasonal cycle. The average density is about 10⁸ cells/1 in the Etang de Berre, and about double that amount in the Etang de Vaïne. Differences in phytoplankton abundance and composition at the various stations or at various depths are slight.     

The Saline Lakes of Saskatchewan IV. Primary Production by Phytoplankton in Selected Saline Ecosystems

Primary production by phytoplankton, efficiency of photosynthesis, and chlorophyll-a concentrations were determined for seven saline lakes that varied widely in ionic concentration and composition. The investigations were done during the summer months of 1972 and 1973. Productivity ranged from 0.001 to 11.135 g C m⁻³ day⁻¹ and 0.053 to 7.968 g C m⁻² day⁻¹. Highest productivities were measured in two lakes that supported blooms of Aphanizomenon flos-aquae and Nodularia spumigena, respectively. Species of Cyanophyceae, Bacillariophyceae and Chlorophyceae dominated the phytoplankton of the study lakes. Active chlorophyll-a ranged from 0.01 to 116 mg m⁻³. Integral photosynthetic efficiency estimates were <1% except during phytoplankton blooms when they were considerably higher. The overall range of 0.03 to 3.8% is concordant with estimates for other lacustrine ecosystems. The extinction of light caused by photo-synthetic processes, or in situ efficiency, was <1% in the trophogenic zone for most lakes but, it was considerably higher during blooms. In situ efficiencies invariably increased with depth in ail lakes.     

24-hour Pattern in Lag Time of Response by Firemen to Calls for Urgent Medical Aid

The aim of the study was to assess the group 24-h pattern of lag time (LT) in response by regular and volunteer firemen (RFM and VFM) to calls for medical help (CFMH), specifically calls for out-of-hospital cardiac arrest (OHCA). LT, duration in min between a CFMH and departure of service vehicle equipped with a semiautomated defibrillator and generally staffed with four well-trained and ready-to-go FM, represents the integrated duration of several processes, each with separate reaction and decision-making times. The exact time of each CFHM (in min, h, day, month, yr) was recorded electronically, and the exact departure time from the station of the responding FM vehicle was recorded by an on-duty FM. Overall, CFMH made up 53?±?9% (SEM) of all emergencies calls for aid. To standardize the study methods, the reported findings are based on 568 CFMH specifically regarding OHCA that occurred during the 4-yr study span (January 2005 to December 2008). CFMH exhibited a 24-h pattern with a major peak at 10:00?h (mean?±?SEM: n?=?9.5?±?1.6) and major trough at 01:00?h (n?=?1.3?±?0.3; t test, p?<?.001). From year to year and season to season, a 24-h pattern was detected in the total of CFMH/h with two peaks (～10:00 and ～17:00h) and two troughs (～01:00 and ～15:00?h) (analysis of variance [ANOVA], p?<?.01; Cosinor, p?<?.05 to?<?.003), with neither season- nor year-related differences (χ², p?>?.05). In CFMH/h pooled time series, ANOVA-detected differences between the hourly means (p?<?.01), and Cosinor analysis validated a 24-h rhythm (p?<?.002). In raw data, the longest LT, indicative of poorest performance, occurred at 05:00?h (8.8?±?0.7?min) and the trough of LT, indicative of best performance, at 16:00?h (4.3?±?0.8?min (t test, p?<?.02). 24-h patterning in LT was validated both by ANOVA of hourly means (p?<?.0006) and Cosinor analysis (p?<?.05), with longest LT ～05:00?h and shortest LT ～16.00?h for data of the individual yearly time-series data. The 24-h LT rhythm was also validated in the pooled time series by Cosinor (p?<?.0001), with the 24-h mean?±?SEM?=?6?±?0.17?min and acrophase (peak) of 03:00?h?±?88?min (SD). Curve patterns of CFMH/h and LT/h differed widely. As a group phenomenon, the LT 24-h rhythm mimics the 24-h pattern of performance, as demonstrated by many laboratory and field investigations. The stability of the LT rhythm between years and seasons and its weak relationship with the CFMH 24-h pattern favors the hypothesis of an endogenous component or origin. The nighttime trough of performance is presumably linked to the elevated risk of work accidents in the same population of FM.     

Water quality and plankton periodicity in two contrasting mine lakes in Jos,Nigeria

Water quality and plankton periodicity was studied in two mine lakes near Jos in the younger granite area of Plateau State, Nigeria. The investigation was carried out for 8 months. Transparency, pH and NO₃-N were significantly higher in Lake II while DOM, alkalinity, PO ₄ ^3– -P, BOD and chloride were significantly higher in Lake I. The order of dominance in Lake I was Bacillariophyceae, Cyanophyceae, Chlorophyceae and Dinophyceae while for Lake II; Chlorophyceae, Cyanophyceae, Bacillariophyceae and Dinophyceae. In Lake I the zooplankton in order of dominance were Cladocera, Rotifera, Copepoda, and nauplii and in Lake II Cladocera, Copepoda, Rotifera and nauplii. Although both lakes would seem unproductive based on the PO ₄ ^3– -P and NO ₃ ^– -N levels, Lake I appears more productive than Lake II.