scholarly journals Distribution of phytobenthos along the coast of Lebanon

2000 ◽  
Vol 1 (2) ◽  
pp. 143 ◽  
Author(s):  
S. LAKKIS ◽  
V. NOVEL-LAKKIS

A phytosociological study of the phytobenthos was carried out along the coast of Lebanon during 1996-97. Samples were collected seasonally at six sites, some of which showed distinct pollution signature. Quadrates of 0.04 m-2 were taken at selected stations fixed on transects perpendicular to the rocky shore and covering the supralittoral, the mediolittoral and infralittoral zones. The taxonomic composition, the abundance and species diversity of algal community were analysed in relation to environmental factors. A total of 230 taxa were identified during the period of survey. Several sources of pollution, resulted in the reduction of macroalgae biomass and of the taxonomic diversity. Several Indo-Pacific species were found within the different phytocoenoses of the area; most of them were introduced into the Levantine Basin through the Suez Canal. These species, that were introduced into the Eastern Mediterranean, formed permanent populations; some of them were highly spread and dominated over other endemic species or even they replaced them.

Author(s):  
Alexander Viacheslavovich Gorbunov ◽  
Oleg Viacheslavovich Gorbunov ◽  
Nikita Il’ich Kochetkov ◽  
Dmitry Lvovich Nikiforov-Nikishin

The purpose of the study was to determine the degree of saprobity of the artificial extension of the Vytravki riverbed (left tributary of the Dubna river) in the Sergiev Posad district of the Moscow region, based on the taxonomic composition of the pelagial and littoral algal flora. For this purpose, the systematic position of algae was determined using a number of domestic and foreign sources, as well as using the electronic database AlgaeBase. The most attention was paid to common indicator types, according to the literature data. Algological samples were taken in accordance with generally accepted methods; the main part of the samples was processed immediately after collection on site, the rest of the material was fixed with a formalin solution and Prat medium for detailed study in laboratory conditions under a microscope. According to the results of the study of hydrobiological samples, the composition of algal flora in the summer-autumn period was determined. There is a large species diversity of algae, represented by most of the divisions characteristic of the Central part of Russia. The green, diatomaceous, and blue-green algae divisions were the most represented. Maximum species diversity was observed for the genera Scenedesmus (9 species) and Pediastrum (10 species). Diatoms are the second group in terms of frequency of occurrence of species that live both in standing water and in rheophilic conditions. Blue-green algae were represented by pelagic forms, with a small frequency of occurrence. Among them, the genera Anabaena (5 species) and Microcystis (3 species) are notable for their high species diversity. The algal flora of the pond was marked divisions, dinophyceae and kropotova, typical for oligotrophic and distrophic reservoirs, indicating a high quality water environment. The established hydrochemical parameters of the reservoir were normal and were similar to the reservoirs of Central Russia at the end of the growing season, which were not exposed to anthropogenic impact.


2008 ◽  
Vol 9 (1) ◽  
pp. 173 ◽  
Author(s):  
N. SIMBOURA

A specimen of Glycinde bonhourei Gravier, 1904, an Indo-Pacific species, was found at a station near the metalliferous waste disposal in the Northern Evvoikos Gulf (Aegean Sea, eastern Mediterranean). This is the second report of this species in the Mediterranean Sea after its first finding in the Levantine basin (Israel and Egypt). This paper provides new information on its distributional range in the Mediterranean Sea.


2021 ◽  
Author(s):  
Qinggeer BORJIGIN ◽  
Bizhou ZHANG ◽  
Xiaofang Yu ◽  
Julin Gao ◽  
Xin ZHANG ◽  
...  

Abstract A lignocellulolytic microbial consortium holds promise for the in situ biodegradation of crop straw and the comprehensive and effective utilization of agricultural waste. In this study, we applied metagenomics technology to comprehensively explore the metabolic functional potential and taxonomic diversity of the microbial consortia CS (cultured on corn stover) and FP (cultured on filter paper).Analyses of the metagenomics taxonomic affiliation data showed considerable differences in the taxonomic composition and functional profile of the microbial consortia CS and FP. The microbial consortia CS primarily contained members from the genera Pseudomonas, Stenotrophomonas, Achromobacter, Dysgonomonas, Flavobacterium and Sphingobacterium, as well as Cellvibrio, Azospirillum, Pseudomonas, Dysgonomonas and Cellulomonas in FP. The COG and KEGG annotation analyses revealed considerable levels of diversity. Further analysis determined that the CS consortium had an increase in the acid and ester metabolism pathways, while carbohydrate metabolism was enriched in the FP consortium. Furthermore, a comparison against the CAZy database showed that the microbial consortia CS and FP contain a rich diversity of lignocellulose degrading families, in which GH5, GH6, GH9, GH10, GH11, GH26, GH42, and GH43 were enriched in the FP consortium, and GH44, GH28, GH2, and GH29 increased in the CS consortium. The degradative mechanism of lignocellulose metabolism by the two microbial consortia is similar, but the annotation of quantity of genes indicated that they are diverse and vary greatly. The lignocellulolytic microbial consortia cultured under different carbon conditions (CS and FP) differed substantially in their composition of the microbial community at the genus level. The changes in functional diversity were accompanied with variation in the composition of microorganisms, many of which are related to the degradation of lignocellulolytic materials. The genera Pseudomonas, Dysgonomonas and Sphingobacterium in CS and the genera Cellvibrio and Pseudomonas in FP exhibited a much wider distribution of lignocellulose degradative ability.


Author(s):  
Arpana Yadav ◽  
Dhananjay Kumar ◽  
Ram Sharan Singh ◽  
Lalit K. Pandey ◽  
Jyoti Rai

Effect of nutrient enrichment on periphyton was studied using chemical diffusing substrates that released, singly or in combination, PO43−-P and nitrogen, both NO3−-N and NH4+-N. The study was carried out in March and June 2014 as these two time periods showed abundance of different groups of algae. Whereas diatoms and green algae were abundant in March, cyanobacteria dominated in June. Nitrogen was primarily growth limiting in river water as its enrichment enhanced the growth of periphyton. Phosphate limitation was secondary in nature. Enrichment of NH4+-N caused greater enhancement of periphytic growth than that of NO3−-N. Nutrient enrichment reduced species diversity, further enhancing total biovolume of the periphytic group that was predominant at that particular point of time. Nutrient enrichment markedly increased cyanobacterial populations in June due inter alia to high temperature. In spite of nutrient enrichment, the periphytic biomass did not reach the level (chla≥ 100–150 mg m−2) considered as the nuisance, except in March when combined enrichment of PO43−-P and NO3−-N greatly enhanced the periphytic biomass.


Diversity ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 116 ◽  
Author(s):  
Peter Sprick ◽  
Andreas Floren

From 1992 to 2009, 334 trees were sampled by insecticidal knockdown on Borneo, Malaysia. Here, we describe the taxonomic composition of the 9671 specimens and 1589 species Curculionoidea collected (with additional notes on Cerambycidae). We found a largely unknown fauna with an assumed proportion of over 80% of species new to science, including all 33 Apionidae and 26 Ceutorhynchinae species. Specialists could usually identify only a few specimens leaving the remaining beetles for further investigation. The samples contain numerous genera, two tribes (Egriini, Viticiini), one subfamily (Mesoptiliinae) and one family (Belidae) new to Borneo and several genera not recorded west of the Wallace line before. These data show how little is known about canopy diversity. The lack of taxonomic knowledge implies a respective lack of autecological knowledge and is alarming. Some taxa differed conspicuously between primary and disturbed forests. In contrast to common literature, our results let us conclude that current efforts to narrow down the extent of tropical diversity and its ecological importance must consider the enormous species diversity of the canopy.


2000 ◽  
Vol 12 (3) ◽  
pp. 276-287 ◽  
Author(s):  
Joseph T. Eastman

Antarctica is a continental island and the waters of its shelf and upper slope are an insular evolutionary site. The shelf waters resemble a closed basin in the Southern Ocean, separated from other continents by distance, current patterns and subzero temperatures. The benthic fish fauna of the shelf and upper slope of the Antarctic Region includes 213 species with higher taxonomic diversity confined to 18 families. Ninety-six notothenioids, 67 liparids and 23 zoarcids comprise 45%, 32% and 11% of the fauna, a combined total of 88%. In high latitude (71–78°S) shelf areas notothenioids dominate abundance and biomass at levels of 90–95%. Notothenioids are also morphologically and ecologically diverse. Although they lack a swim bladder, the hallmark of the notothenioid radiation has been repeated diversification into water column habitats. There are pelagic, semipelagic, cryopelagic and epibenthic species. Notothenioids exhibit the disproportionate speciosity and high endemism characteristic of fish species flock. Antifreeze glycopeptides originating from a transformed trypsinogen gene are a key innovation. It is not known when the modern Antarctic shelf fauna assumed its current taxonomic composition. A late Eocene fossil fauna was taxonomically diverse and cosmopolitan. There was a subsequent faunal replacement with little carryover of families into the modern fauna. Basal notothenioid clades probably diverged in Gondwanan shelf locations during the early Tertiary. Dates inferred from molecular sequences suggest that phyletically derived Antarctic clades arose 15–5 m.y.a.


2021 ◽  
Vol 9 ◽  
Author(s):  
Sharif Jemaa ◽  
Celine Mahfouz ◽  
Maria Kazour ◽  
Myriam Lteif ◽  
Abed El Rahman Hassoun ◽  
...  

Despite emerging and increasing concerns related to marine micro and macroplastics, no systematic surveys have been undertaken yet in the Lebanese marine area. To understand the spatio-temporal variation of plastic litter (macro and microplastics) in the Lebanese marine environment and to determine the sources of pollution, this study investigated the characteristics of plastic pollution in sea surface waters during wet and dry seasons in 22 sites of Beirut and Tyre regions. A total of 23,023 items were identified and assessed according to the shape, color, and concentration; moreover, the risk of microplastics (MPs) contamination was explored based on a risk assessment model. The obtained results demonstrated that the average macroplastics concentration was 0.45 ± 0.6 items/m3. The average microplastics concentration was found to be 20.1 ± 21.8 and 3.78 ± 5.2 items/m3 in spring and fall respectively. During fall, MPs fragments were dominant in Beirut (97%) and Tyre (91%), and no pellets were observed. During spring, filaments were most encountered in Beirut (76.5%). The most dominant marine litter color was blue followed by black and white. The Pollution Load Index (PLI) values showed a moderate contamination of the Lebanese coast with MPs (PLI: 5.79 ± 3.93) except for several sites in Beirut that showed high values of PLI, highlighting the local influence of cities and rivers on MPs concentration. This study serves as an important baseline for understanding the characteristics of the seasonal variation of MPs along the Lebanese marine environment; it will help stakeholders and countries to take proactive and reactive actions to face plastic litter pollution in the Lebanese coastal area.


2019 ◽  
Author(s):  
Hsin-Nan Lin ◽  
Yaw-Ling Lin ◽  
Wen-Lian Hsu

ABSTRACTCharacterizing the taxonomic diversity of a microbial community is very important to understand the roles of microorganisms. Next generation sequencing (NGS) provides great potential for investigation of a microbial community and leads to Metagenomic studies. NGS generates DNA fragment sequences directly from microorganism samples, and it requires analysis tools to identify microbial species (or taxonomic composition) and estimate their relative abundance in the studied community. However, only a few tools could achieve strain-level identification and most tools estimate the microbial abundances simply according to the read counts. An evaluation study on metagenomic analysis tools concludes that the predicted abundance differed significantly from the true abundance. In this study, we present StrainPro, a novel metagenomic analysis tool which is highly accurate both at characterizing microorganisms at strain-level and estimating their relative abundances. A unique feature of StrainPro is it identifies representative sequence segments from reference genomes. We generate three simulated datasets using known strain sequences and another three simulated datasets using unknown strain sequences. We compare the performance of StrainPro with seven existing tools. The results show that StrainPro not only identifies metagenomes with high precision and recall, but it is also highly robust even when the metagenomes are not included in the reference database. Moreover, StrainPro estimates the relative abundance with high accuracy. We demonstrate that there is a strong positive linear relationship between observed and predicted abundances.


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