scholarly journals Diversity and distribution of diatoms in Bagmati River, Kathmandu, Nepal

2018 ◽  
Vol 6 ◽  
pp. 6-15
Author(s):  
Shiva Kumar Rai ◽  
Sudip Khadka
Keyword(s):  
Aquatic Macrophytes ◽  
Habitat Diversity ◽  
Diatom Cell ◽  
Different Seasons ◽  
Bagmati River

Diversity and distribution of diatoms in different seasons from different localities and habitats of Bagmati River, Kathmandu was studied. Samples were collected as epilithic forms using a toothbrush, epipelic forms using a dropper, and epiphytic forms by squeezing aquatic macrophytes and were preserved in FAA solution. The dominant diatom taxa of Bagmati river were Achnanthes crenulata, Gomphonema pseudoaugur, Nitzschia linearis, N. palea, Pinnularia cf divergens and Surirella linearis. Out of 48 taxa reported, maximum taxa (87.5%) were found at Mulkharka site whereas taxa were minimum (39.58%) at Pashupati-Guheshwori site. The sizes of diatom cell, from largest to smallest, also followed the same pattern as above. Ten diatom taxa were common in all three sites. Seasonal and habitat diversity of diatom studied in Mulkharka site showed that the maximum number of taxa was reported during summer (92.85%) and least during winter (23.8%), and maximum taxa were found as epilithic (85.71%) followed by epipelic (38.09%) and epiphytic (33.33%).

scholarly journals Habitat diversity and benthic functional trophic groups at Serra do Cipó, Southeast Brazil

2001 ◽  
Vol 61 (2) ◽  
pp. 259-266 ◽  
Author(s):  
M. CALLISTO ◽  
P. MORENO ◽  
F. A. R. BARBOSA
Keyword(s):  
Riparian Vegetation ◽  
Aquatic Macrophytes ◽  
Mesh Size ◽  
Habitat Diversity ◽  
Trophic Groups ◽  
Macroinvertebrate Communities ◽  
Lotic Ecosystems ◽  
Serra Do Cipó ◽  
Trophic Resources ◽  
Doce River

The assessment of the diversity of habitats and the characterisation of the functional trophic groups of benthic macroinvertebrate communities of some rivers of Serra do Cipó (MG) were the main objectives of this study. The available trophic resources and the types of substrata were characterised along with the structure and composition of their using functional trophic groups. Serra do Cipó is a watershed divisor of the São Francisco and Doce River basins, including a series of streams and rivers, of good water quality and well preserved ecological characteristics. Samples were collected in Cipó, Peixe and Preto do Itambé rivers, besides the Indaiá and Capão da Mata streams at 26 sampling stations, during the rainy (February) and dry (October) seasons of 1998, using "Kicking nets" of 0.125 mm mesh size. The group of collectors (Baetidae, Leptophlebiidae and Leptohyphidae) was the most abundant, followed by collector-predators (Hydrophilidae, Ceratopogonidae, Chironomidae-Tanypodinae), and detritivorous-herbivores (Oligochaeta). The riparian vegetation, together with the aquatic macrophytes, are the substrata containing the highest richness of functional trophic groups and the higher habitat diversity. The results suggest that the use of functional trophic groups, together with habitat evaluation, are efficient tools in the evaluation of the diversity of benthic macroinvertebrates, particularly in altitudinal lotic ecosystems.

The role of the diatom cell form in the competition for light energy

2019 ◽  
pp. 37-47
Author(s):  
Aleksey V. Fedorov ◽  
Leonid E. Paramonov ◽  
Vladimir A. Silkin
Keyword(s):  
Ecological Niche ◽  
The Black Sea ◽  
Diatom Cell ◽  
Diatom Species ◽  
Absorbed Energy ◽  
Cell Form ◽  
Different Seasons ◽  
Phytoplankton Cell ◽  
Competition For Light

We proposed a new parameter regulating distribution of the species – the daily average absorbed energy of PAR by a unit of phytoplankton cell volume, determined by the shape, size and concentration of pigments. We calculated this parameter for some dominant diatom species of the northeastern part of the Black Sea and normalize it by the average daily PAR for periods of dominance. We established that for species successfully compete for an ecological niche this parameter should be approximately at the same level in different seasons.

scholarly journals Nitrogen and phosphorus resorption efficiency, and N : P ratios in natural populations of Typha domingensis Pers. in a coastal tropical lagoon

2013 ◽  
Vol 25 (2) ◽  
pp. 124-130
Author(s):  
Bruno dos Santos Esteves ◽  
Marina Satika Suzuki
Keyword(s):  
Aquatic Macrophytes ◽  
Natural Populations ◽  
Typha Domingensis ◽  
Resorption Efficiency ◽  
Nitrogen And Phosphorus ◽  
P Limitation ◽  
Tropical Lagoon ◽  
P Content ◽  
Different Seasons ◽  
One Year

AIM: We studied nitrogen (N) and phosphorus (P) resorption patterns in Typha domingensis Pers. in a tropical coastal lagoon during different seasons of throughout one year. METHODS: Resorption of N and P is uttered as resorption efficiency (NRE and PRE, respectively), which may be used as an indicator of a nutrient limitation. Higher resorption efficiency values might indicate limitation of a certain element for the growth of aquatic macrophytes. RESULTS: N was inferred to be less limiting than P for the growth of T. domingensis in Campelo Lagoon, since N content varied less than P content and resorption efficiency of N was lower than that of P and, concomitantly, low resorption efficiency of this element. However, T. domingensis of Campelo Lagoon frequently utilized P that was already present in its tissues, contributing to the longer residence time of this element in system. Green leaves of T. domingensis showed N : P ratio, ranging 49-96, corroborating the inference of P limitation. CONCLUSIONS: N : P ratio and resorption efficiency indicate P limitation by T. domingensis in Campelo Lagoon.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

Wing lengths of Clamorous Reed Warblers Acrocephalus stentoreus in Israel

Ring ◽  
2004 ◽  
Vol 26 (2) ◽  
pp. 89-92
Author(s):  
John Morgan
Keyword(s):  
Wing Length ◽  
First Year ◽  
Comparable Data ◽  
Reed Warbler ◽  
Data Set ◽  
Acrocephalus Scirpaceus ◽  
Different Seasons ◽  
A Site ◽  
Made In ◽  
New Discovery

Wing lengths of Clamorous Reed Warblers Acrocephalus stentoreus in Israel Wing length measurements taken from first-year, pre- and post-moulting (annual, complete) Clamorous Reed Warblers were recorded at a site in northern Israel. The resulting data set was examined using a time-series of residuals (CUSUM). Results from this analysis can explain the reported heterogeneity found in a comparable data set by Merom et al. (1999). Further observations made in their paper are rebutted: (1) an implied assumption that Reed Warbler (Acrocephalus scirpaceus) spring migration in Israel ends by 1 May is contrary to other publications; (2) the late autumn occurence in N Israel of longer-winged 1st cal. yr. Reed Warblers, unconvincingly explained as either delayed migration by larger individuals or post fledging feather growth, is most likely due to birds from different provenances origins moving at different seasons; (3) growth during adulthood in Reed Warbler is not a new discovery, though presented as such.

Current Status of Anserinae Wintering in Azov-Black Sea Region of Ukraine

2019 ◽  
Vol 53 (4) ◽  
pp. 297-312
Author(s):  
Yu. O. Andryushchenko ◽  
V. S. Gavrilenko ◽  
V. A. Kostiushyn ◽  
V. N. Kucherenko ◽  
A. S. Mezinov ◽  
...  
Keyword(s):  
Black Sea ◽  
Current Status ◽  
Anser Anser ◽  
Scientific Publications ◽  
Climate Conditions ◽  
Black Sea Region ◽  
Chen Caerulescens ◽  
Branta Bernicla ◽  
The North ◽  
Different Seasons

Abstract In the article is analyzed own field data of the authors and scientific publications on the wintering of Anserinae in the Azov-Black Sea region of Ukraine in 1900–2017, but the main data was obtained in frame of international mid-winter counts (IWC) in 2005–2017. It was found that 9 species of Anserinae occur in this region during the different seasons of the year: Anser anser — nesting, wintering and migrating; Rufibrenta ruficollis, A. albifrons, A. erythropus, A. fabalis — migrating and wintering; Branta canadensis, Branta leucopsis, Branta bernicla, Chen caerulescens — vagrant or birds which flew away from captivity (zoo etc.). Eulabeia indica — is possible vagrant species. The most numerous wintering species is A. albifrons, common — Rufibrenta ruficollis, not numerous — Anser anser, the other species are not met annually and registered in a very small number. There was almost tenfold drop in number of wintering geese in the Azov-Black Sea region of Ukraine during the period of counts. The main reasons of such reducing of geese amount are the followwing: weather and climate conditions, changes in the forage acessibility, hunting and poaching pressure, poisoning as a result of deratization of agricultural lands, and from 2014 — the militarization of the Syvash area and stop of water supplying of Crimea through the North Crimean channell. It is likely that the factors mentioned above led to relocating of wintering areas of Anserinae, and resulted in decreasing of their amount in this region.

Some small-sized Cosmarium (Conjugatophyceae, Desmidiales) from sphagnum bogs of Moscow Region

2013 ◽  
Vol 47 ◽  
pp. 13-20
Author(s):  
O. V. Anissimova
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Moscow Region ◽  
Biological Station ◽  
Sphagnum Bogs ◽  
Different Seasons ◽  
Scanning Electron

Algae samples were collected during different seasons from 1997 to 2011 in two swamps located at Zvenigorod Biological Station in Moscow Region. There were found 25 Cosmarium species and varieties, 9 taxa of them being new to the region. Descriptions of the taxa were specified by observation of cell wall ornamentation with light and scanning electron microscopy. Original descriptions, photos and drawings of algae are presented.

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