Distribution of blue-green algae (Cyanophyta) in streams of Mt. Stara planina: Serbia

Distribution of blue-green algae was studied at 14 sites along five streams in the Stara Planina mountains. Algological samples were taken from the community of benthos and periphyton in the spring (March-May 1991), summer (June-August 1991, August 1996, July 1997), and autumn (September-November 1991, September 1997). Algae of the classes Chamaesiphonophyceae (species of the genus Chamaesiphon) and Hormogoniophyceae (species of the genera Symploca, Phormidium, Oscillatoria, Schizothrix, Nostoc, Rivularia Homoeothrix, Tolypothrix, and Plectonema) were recorded. The species Chamaesiphon cylindricus, Symploca radians, Phormidium coutinhoi, Nostoc coeruleum, Homoeothrix janthina, Plectonema thomasinianum, and Tolypothrix distorta were registered herein first time in Serbia. Occurrence of blue-green algae in highland brooks and rivers of the Stara Planina mountains was monitored in relation to a large number of abiotic factors e.g. altitude above level, stream dimensions (width and depth), substrate bottom type (%), current flow rate, water temperature and pH oxygen concentration, concentrations of nitrates and phosphates, and BOD5, using Principal Coordinates analysis (PCX)).

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Distribution, biomass and community structure of demersal fishes of the Gulf of Carpentaria, Australia

Marine and Freshwater Research ◽

10.1071/mf9940375 ◽

1994 ◽

Vol 45 (3) ◽

pp. 375 ◽

Cited By ~ 23

Author(s):

SJM Blaber ◽

DT Brewer ◽

AN Harris

Keyword(s):

Community Structure ◽

Abiotic Factors ◽

Fish Fauna ◽

Distribution Patterns ◽

Demersal Fish ◽

Fish Distribution ◽

Sediment Type ◽

Principal Coordinates Analysis ◽

Main Site ◽

Principal Coordinates

The demersal fish fauna of the Gulf of Carpentaria was surveyed during November and December 1990. Over 300 species from 85 families were caught by trawling a systematic grid of 107 stations. The absolute mean biomass was 124.8 kg ha-1 (s.e. =44.1) for day trawls and 53.7 kg ha-1 (s.e. =6.0) for night trawls. The overall mean catch rates were 421.3 kg h-1 (s.e. = 128.5) for day trawls and 198.6 kg h-1 (s.e. =21.5) for night trawls. Biomasses were twice as high in the prawn-trawling grounds of Albatross Bay, the south-eastern gulf and Groote Eylandt as they were elsewhere in the gulf. Twenty-five species made up 75% of the biomass; the dominant families were Haemulidae, Carangidae, Leiognathidae and Nemipteridae. Community-structure and distribution patterns were analysed by numerical classification techniques and principal-coordinates analysis. These indicated six main site groups and 15 fish community groups, based on fish species occurrences and biomasses. There was a relationship between fish distribution patterns and depth of water but not other abiotic factors recorded (sediment type, salinity, temperature and turbidity).

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Effects of abiotic factors on nitrogen fixation by blue-green algae in Antarctica

Polar Biology ◽

10.1007/bf00303174 ◽

1983 ◽

Vol 2 (2) ◽

pp. 95-100 ◽

Cited By ~ 29

Author(s):

A. Davey

Keyword(s):

Nitrogen Fixation ◽

Green Algae ◽

Abiotic Factors ◽

Blue Green Algae

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Edge effect on carabid assemblages along forest-grass transects

Web Ecology ◽

10.5194/we-2-7-2001 ◽

2001 ◽

Vol 2 (1) ◽

pp. 7-13 ◽

Cited By ~ 14

Author(s):

T. Magura ◽

B. Tóthmérész ◽

T. Molnár

Keyword(s):

Edge Effect ◽

Abiotic Factors ◽

Canopy Cover ◽

Distinct Species ◽

Forest Edge ◽

Principal Coordinates Analysis ◽

Forest Interior ◽

Principal Coordinates ◽

Significant Edge ◽

Characteristic Species

Abstract. During 1997 and 1998, we have tested the edge-effect for carabids along oak-hornbeam forest-grass transects using pitfall traps in Hungary. Our hypothesis was that the diversity of carabids will be higher in the forest edge than in the forest interior. We also focused on the characteristic species of the habitats along the transects and the relationships between their distribution and the biotic and abiotic factors. Our results proved that there was a significant edge effect on the studied carabid communities: the Shannon diversity increased significantly along the transects from the forest towards the grass. The diversity of the carabids were significantly higher in the forest edge and in the grass than in the forest interior. The carabids of the forest, the forest edge and the grass are separated from each other by principal coordinates analysis and by indicator species analysis (IndVal), suggesting that each of the three habitats has a distinct species assemblages. There were 5 distinctive groups of carabids: 1) habitat generalists, 2) forest generalists, 3) species of the open area, 4) forest edge species, and 5) forest specialists. It was demonstrated by multiple regression analyses, that the relative air moisture, temperature of the ground, the cover of leaf litter, herbs, shrubs and canopy cover, abundance of the carabids’ preys are the most important factors determining the diversity and spatial pattern of carabids along the studied transects.

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Morphological and Ecological Features of Some Nematodes of the Genus Rhabdochona in Marinka Obtained From Fergana Valley, Uzbekistan

10.21203/rs.3.rs-341355/v1 ◽

2021 ◽

Author(s):

Abdurakhim Kuchboev ◽

Eldor Kh Najmidinov ◽

Muzaffar A Mukhamediev ◽

Rokhatoy R Karimova ◽

Kader Yildiz

Keyword(s):

Dissolved Oxygen ◽

Flow Rate ◽

Abiotic Factors ◽

Nematode Species ◽

Mountain Rivers ◽

Ecological Features ◽

Central Asian ◽

Nutritional Characteristics ◽

First Time ◽

Central Asian Republics

Abstract The aim is to study the morphological and ecological features of some nematode species of the genus Rhabdochona parasites of marinka fish in the Fergana Valley, Uzbekistan. Rhabdocona gnedini, Rhabdochona denudata and Rhabdocona hellichi turkestanica were detected as 5.3%, 7.9% and 3.7%, respectively. According to the Authors’ knowledge, Rh. hellichi turkestanica was recorded in Uzbekistan and Central Asian republics for the first time. Rhabdocona spp. were only detected in the intestine of marinkas lived in the mountain rivers Rezaksay, Chodaksay and small tributaries of the Syrdarya river in western Fergana. Some abiotic factors such as the flow rate, water temperature and high content of dissolved oxygen in it, as well as the nutritional characteristics of the fish can be most important factors to spread of Rh.denudata, Rh. gnedini, Rh. hellichi turkestanica in marinkas from mountain rivers of the Fergana Valley.

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Genetic Structure and Eco-Geographical Differentiation of Wild Sheep Fescue (Festuca ovina L.) in Xinjiang, Northwest China

10.20944/preprints201707.0047.v1 ◽

2017 ◽

Author(s):

Chenglin Zhang ◽

Jianbo Zhang ◽

Yan Fan ◽

Ming Sun ◽

Wendan Wu ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Abiotic Factors ◽

Northwest China ◽

Group Method ◽

Principal Coordinates Analysis ◽

High Genetic Diversity ◽

Festuca Ovina ◽

Principal Coordinates ◽

Genetic Diversity And Structure

Glaciation and mountain orogeny have generated new ecologic opportunities for plants, favoring an increase in the speciation rate. Moreover, they also act as corridors or barriers for plant lineages and populations. High genetic diversity ensures that species are able to survive and adapt. Gene flow is one of the most important determinants of the genetic diversity and structure of out-crossed species, and it is easily affected by biotic and abiotic factors. The aim of this study was to characterize the genetic diversity and structure of an alpine species, Festuca ovina L., in Xingjiang, China. A total of 100 individuals from 10 populations were analyzed using six amplified fragment length polymorphism (AFLP) primer pairs. A total of 583 clear bands were generated, of which 392 were polymorphic; thus, the percentage of polymorphic bands (PPB) was 67.24%. The total and average genetic diversities were 0.2722 and 0.2006 (0.1686-0.2225), respectively. The unweighted group method with arithmetic mean (UPGMA) tree, principal coordinates analysis (PCoA) and STRUCTURE analyses revealed that these populations or individuals could be clustered into two groups. The analysis of molecular variance analysis (AMOVA) suggested that most of the genetic variance existed within a population, and the genetic differentiation (Fst) among populations was 20.71%. The Shannon differentiation coefficient (G’st) among populations was 0.2350. Limited gene flow (Nm = 0.9571) was detected across all sampling sites. The Fst and Nm presented at different levels under the genetic barriers due to fragmentation. The population genetic diversity was significant relative to environmental factors such as temperature, altitude and precipitation.

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Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060386 ◽

1967 ◽

Vol 25 ◽

pp. 74-75

Author(s):

L. V. Leak

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Green Algae ◽

Three Dimensional ◽

Freeze Fracture ◽

Electron Microscopic ◽

Photosynthetic Membranes ◽

Blue Green Algae ◽

Cell Biol ◽

Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

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