scholarly journals Abundance, diversity and distribution of macrophyte communities in neighboring lakes of different trophic states and morphology in north-central Greece

2011 ◽  
Vol 63 (3) ◽  
pp. 763-774 ◽  
Author(s):  
Chrisoula Pirini ◽  
Vasiliki Karagiannakidou ◽  
Savvas Charitonidis
Keyword(s):  
Environmental Factors ◽  
Aquatic Vegetation ◽  
Floristic Composition ◽  
Diversity Indices ◽  
North Central ◽  
Wetland Ecosystems ◽  
Central Greece ◽  
Clear Differentiation ◽  
Evenness Indices

The role of aquatic vegetation in wetland ecosystems is closely related with their abundance, diversity and distribution, which in turn represents synergy of various environmental factors. The floristic composition of the aquatic vegetation in two neighboring lakes (Vegoritida and Petron) in north-central Greece was investigated by means of 160 relev?s, which were recorded using the Braun-Blanquet method. The analysis of relev?s based on TWINSPAN clustering showed the existence of 10 plant communities from the Lemnetea, Potametea, Phragmito-Magnocaricetea and Juncetea maritimi classes. The most important environmental factors for the vegetation differentiation in the study area, according to the ordination diagram, are light intensity and water depth of the habitats. The plant species diversity was quantified with species richness, Shannon Diversity and evenness indices at a scale of each relev?, with a sampling size of 20 m2. There was a clear differentiation between the relev?s at the more eutrophic Petron Lake and those at Vegoritida Lake. The mean plot diversity was also calculated for each plant community, to enable comparison of the diversity indices among the communities at the plot level.

The role of the subtropical jet stream during heat wave events over north-central Greece

2006 ◽  
Vol 94 (1-4) ◽  
pp. 219-233 ◽  
Author(s):  
D. P. Brikas ◽  
T. S. Karacostas ◽  
P. J. Pennas ◽  
A. A. Flocas
Keyword(s):  
Heat Wave ◽  
Jet Stream ◽  
North Central ◽  
Central Greece ◽  
Subtropical Jet Stream ◽  
Subtropical Jet

scholarly journals Growth and mortality of transient shrimp populations (Farfantepenaeus spp.) in a coastal lagoon of Mexico: role of the environment and density-dependence

2005 ◽  
Vol 62 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Roberto Pérez-Castañeda ◽  
Omar Defeo
Keyword(s):  
Environmental Factors ◽  
Aquatic Vegetation ◽  
Environmental Temperature ◽  
Abundant Species ◽  
Mortality Rates ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Significant Relationships ◽  
Dependent Processes

Abstract The influence of environmental (temperature, salinity, aquatic vegetation) and density-dependent (abundance of recruits) factors on growth and mortality of four Farfantepenaeus species were evaluated during their period of estuarine residence, through a 2-year field study at Celestun lagoon, Mexico. Growth rates of the three most abundant species (F. brasiliensis, F. duorarum, F. notialis) were positively related with temperature and aquatic vegetation biomass, whereas some significant relationships between environmental factors and mortality rates were also demonstrated. Our results suggest that density-dependent processes regulate growth and mortality in these shrimp populations. Density-dependent mortality was also suggested by a strong compensatory relationship between recruits and juveniles. We conclude that population dynamics of Farfantepenaeus shrimps during their estuarine phase seem to be driven by the combined forces of density-dependent and environmental factors operating together.

The Role of Aquatic Weeds in Changing the Pattern of Ecosystems in Kerala

1981 ◽  
Vol 8 (1) ◽  
pp. 63-66 ◽  
Author(s):  
K. J. Thomas
Keyword(s):  
Aquatic Vegetation ◽  
Floristic Composition ◽  
Water Bodies ◽  
Ecological Processes ◽  
Hydroelectric Reservoirs ◽  
The Past ◽  
Scientific Disciplines ◽  
Manual Labour ◽  
Considerable Loss

A comparative study of the floristic composition of aquatic vegetation growing in certain ponds in parts of Kerala, and those recorded as growing in the same ponds more than 20 years ago, reveals changes that are often extreme. Thus many of the once-dominant species have either dwindled or disappeared. In some ponds, most of the components of the original flora of only a quarter-of-a-century ago have been completely replaced by thick mats of Salvinia over the past two decades. Salvinia multiplies vegetatively very rapidly (cf. Mitchell et al., 1980), forming mats on which secondary colonists grow. This commonly leads to a gradual filling of the pond. Besides, Salvinia infestations also cause considerable loss of water from water-bodies through increased evapotranspiration. If these ecological processes are allowed to continue, many of our water-bodies seem sure to dry up in due course.A well-planned and systematic method of control, involving physical removal—either through manual labour or specially-designed machines—to be followed by biological control (for example by grazing vertebrates or invertebrates), would keep the explosive spread of the weed under check. The huge mass of harvested weed could be utilized for production of organic manure, cooking gas, or hard-boards, or could be dried as packing material. There should also be vigilance by a surveillance squad of experts in the scientific disciplines concerned, which would be effective in preventing further spread of the weed—much as is already being practised with good results for the hydroelectric reservoirs of Kerala.

scholarly journals Steppe-Like Grass Land Vegetation in the Hills around the Lakes of Vegoritida and Petron, North-Central Greece

Hacquetia ◽  
2014 ◽  
Vol 13 (1) ◽  
pp. 121-169 ◽  
Author(s):  
Chrisoula B. Pirini ◽  
Ioannis Tsiripidis ◽  
Erwin Bergmeier
Keyword(s):  
Vascular Plant ◽  
Floristic Composition ◽  
Environmental Parameters ◽  
Nutrient Content ◽  
Natura 2000 ◽  
Soil Reaction ◽  
Bothriochloa Ischaemum ◽  
North Central ◽  
Central Greece ◽  
Dry Grasslands

Abstract The present paper describes the floristic composition and synecology of steppe-like dry grasslands occurring in a Natura 2000 site in North-Central Greece around the two karstic lakes of Vegoritida and Petron. In total, 245 releves of vascular plant species composition and abundance were sampled and subjected to cluster analysis and ordination analysis. Passive explanatory variables, including environmental parameters as well as indicator values, were used to support the ecological interpretation. Four plant communities were distinguished in the area, namely Artemisia campestris-Dasypyrum villosum, Chrysopogon gryllus-Bothriochloa ischaemum, Satureja montana-Artemisia alba and Stipa capillata-Koeleria macrantha. All communities were classified within the Festuco-Brometea class and the Astragalo-Potentilletalia order. Soil properties (soil reaction, moisture and nutrient content) and meso-climate factors (temperature variation along topographic gradients) were identified as the main factors determining the floristic differentiation among the four communities. The dry grasslands harbor a number of species associated with steppic habitats. We discuss the relict character of the steppe-like vegetation.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Role of environmental factors in the etiology of hepatocellular carcinoma

2010 ◽  
Vol 151 (28) ◽  
pp. 1132-1136 ◽  
Author(s):  
István Tornai
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Environmental Factors ◽  
Hepatitis B ◽  
Hepatitis A ◽  
Virus Hepatitis ◽  
B Virus

A krónikus vírushepatitisek jelentik ma a legismertebb okokat a hepatocellularis carcinoma (HCC) kialakulásában. A krónikus B- és C-vírus-hepatitis a májrákok körülbelül 40-50%-át okozza. A nyugati típusú társadalmakban a HCC előfordulása folyamatosan növekvő tendenciát mutat. Az alkohol számít a környezeti tényezők közül a legfontosabbnak, bár az alkoholfogyasztás a legtöbb országban csökken. Ez aláhúzza az egyéb környezeti tényezők fontosságát is. Az elfogyasztott alkoholmennyiséggel egyenes arányban növekszik a cirrhosis és a következményes HCC gyakorisága nőkben és férfiakban egyaránt. A kémiai anyagok közül a legismertebb a Kínában és Afrikában elterjedt aflatoxin, amely a gabonaféléket szennyező mycotoxin. Hasonló területeken endémiás, mint a hepatitis B-vírus, együtt szinergista hatást fejtenek ki. A dohányzás is egyértelműen bizonyított hepatocarcinogen hatással rendelkezik. Ez is jelentősen fokozódik, ha alkoholfogyasztással vagy vírushepatitisszel társul. Társadalmilag talán a legfontosabb az elhízás, a következményes nem alkoholos zsírmáj, illetve steatohepatitis és a 2-es típusú cukorbetegség, amelyek prevalenciája egyre fokozódik. Feltehetően ezek állnak a növekvő HCC-gyakoriság hátterében. Az inzulinrezisztencia és az oxidatív stressz képezik a legfontosabb patogenetikai lépéseket a májsejtkárosodásban. További fontos rizikótényező az orális fogamzásgátlók elterjedt használata. Egyes foglalkozások esetén a tartós szervesoldószer-expozíció is növeli a HCC rizikóját. Védelmet jelenthetnek az antioxidánsok, a szelén, a gyógyszerek közül a statinok és a feketekávé-fogyasztás.

Geobotanical studies at the Caucasus: a review of materials of the International Conference “Flora and conservation in the Caucasus: history and current state of knowledge” (Pyatigorsk, May 22–25, 2019)

2019 ◽  
pp. 91-94
Author(s):  
T. M. Lysenko ◽  
V. Yu. Neshatayeva ◽  
Z. V. Dutova
Keyword(s):  
Plant Communities ◽  
Aquatic Vegetation ◽  
Plant Cover ◽  
Floristic Composition ◽  
Current Status ◽  
Wide Field ◽  
The Caucasus ◽  
International Conference ◽  
Rare And Endangered Species ◽  
Current State

The International conference “Flora and conservation in the Caucasus: history and current state of knowledge” dedicated to the 130-year anniversary of the Perkalsky Arboretum took place at 22–25 of May 2019 in Pyatigorsk (Stavropol Territory) on the base of the Pyatigorsk Museum of local lore and natural history. The participants were from 11 cities of Russia and 7 Republics of the Caucasus and represented 14 institutions. Proceedings of the conference were published by the beginning of the meeting the book of abstracts includes 49 papers on the study of vascular plants, bryophytes, lichens and fungi, plant communities, as well as the protection of rare and endangered species, unique plant communities, and ecological problems in the Caucasus. The following geobotanical topics were highlighted in 13 papers: forest communities (3 reports), meadow and steppe vegetation (2), xeric open forests (2), communities of ecotone areas (1), structure of populations of rare plant species (3), as well as the history and current status of nature protected areas (2). The great emphasis has been focused on the study of floristic composition and plant populations. Thus, the conference showed that very few studies от vegetation are currently carried out in the Caucasus, and a lot of districts are not affected by the research. The greatest attention is paid to forest vegetation while meadow, steppe, alpine heath and xerophytic communities are studied rather poorly. Besides, there are “white spots” — mire, floodplain and aquatic vegetation. In nowadays, when the anthropogenic impact on the plant cover of the Caucasus is intensively increasing, it is especially important to study natural undisturbed communities preserved in protected natural areas. Another important issue is the conservation of the unique vegetation cover of the whole Caucasus. Thus, the study of vegetation of this region opens a wide field for researchers using various methods of modern plant science.

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