scholarly journals Phytoplankton dynamics in relation to environmental changes in a phytoplankton-dominated Mediterranean lagoon (Cabras Lagoon, Italy)

2012 ◽  
Vol 3 (2) ◽  
pp. 147 ◽  
Author(s):  
B.M. Padedda ◽  
S. Pulina ◽  
P. Magni ◽  
N. Sechi ◽  
A. Lugliè
Keyword(s):  
Nutrient Availability ◽  
Environmental Changes ◽  
Negative Impact ◽  
Inorganic Nitrogen ◽  
Algal Species ◽  
Temporal Variations ◽  
Extreme Weather Events ◽  
Economic Activities ◽  
Phytoplankton Assemblages ◽  
High Nutrient

In Mediterranean lagoons, macrophytes often surpass phytoplankton as the most important primary producers. Less frequently, phytoplankton dominates throughout the year, thus knowledge of its dynamics is relatively limited and scattered. In this study, we assessed over two years the dynamics of phytoplankton assemblages, including potential harmful algal species (HAS), in relation to environmental changes in the phytoplankton-dominated Cabras Lagoon (Sardinia, Italy). The lagoon was characterised by uniform spatial conditions, wide temporal variations in salinity (40 PSU) and high nutrient availability. Phosphorus was highest in summer, possibly recycled within the system, while dissolved inorganic nitrogen increased in winter and spring due to watershed discharge. Chlorophyll a, positively correlated with nutrients and rainfall, showed a typical bimodal pattern with summer-winter blooms. Modifications in phytoplankton composition strongly correlated with extreme weather events, such as intense rainfall. This generated an abrupt salinity decrease that, combined with high nutrient availability, favoured the dominance of Cyanophyceae of reduced cell size, such as Cyanobium and Rhabdoderma species. We suggest that the prolonged and intense dominance of Cyanophyceae, added to other HAS, has a negative impact on the primary economic activities of the lagoon, such as fishery, and generally on the whole lagoon functioning.

DIVERSITY OF FISH LARVAE AROUND THE ESTUARY OF THE BANYUASIN RIVER, SOUTH SUMATERA PROVINCE

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Moh. Rasyid Ridho ◽  
Enggar Patriono ◽  
Sarno Sarno ◽  
Sahira Wirda
Keyword(s):  
Initial Phase ◽  
Sampling Method ◽  
Environmental Changes ◽  
Negative Impact ◽  
Fish Larvae ◽  
River Estuary ◽  
Sampling Technique ◽  
Critical Phase ◽  
Morisita Index ◽  
Index Value

The initial phase of the fish life cycle is a critical phase associated with high mortality due to sensitivity to predators, food availability, and also environmental changes that occur in nature. Disruption of the initial stages of fish life has a negative impact on fish populations. Until now there has been no information about fish larvae around the Banyuasin River Estuary. Therefore, research is needed on the diversity of fish larvae around the Banyuasin River Estuary, South Sumatra Province. This research were used purposive sampling method, sampling technique in the form of Cruise Track Design with continuous parallel survey trajectory. Based on the results of the study found as many as 10 families consisting of 1483 individuals of fish larvae in March and 1013 individuals of fish larvae in May consisting of Engraulidae 1,601 individuals of fish larvae, Mungiloidei as many as 109 individuals, Leiognathidae 50 individuals, Chanidae 453 individuals, Scatophagidae 20 individuals , Belonidae 39 individuals, Gobioididae 5 individuals, Chandidae 183 individuals, Syngnatihidae 6 individuals, and Gobiidae 30 individuals fish larvae. The index value of fish larvae diversity is classified as medium category (March 1.02 and May 1.12), Morisita index shows the distribution pattern of fish larvae classified as a group (March 0-14.17 and May 2.43-10.40 ), and the evenness index value is in the medium category (March 0.437 and May 0.521).

High nutrient availability leads to weaker top-down control of stream periphyton: Compensatory feeding in Ancylus fluviatilis

2018 ◽  
Vol 64 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Alessandra Iannino ◽  
Alexander T. L. Vosshage ◽  
Markus Weitere ◽  
Patrick Fink
Keyword(s):  
Nutrient Availability ◽  
Top Down ◽  
Compensatory Feeding ◽  
Stream Periphyton ◽  
High Nutrient

scholarly journals Mapping Malaria Transmission Risk in Northern Morocco Using Entomological and Environmental Data

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
E. Adlaoui ◽  
C. Faraj ◽  
M. El Bouhmi ◽  
A. El Aboudi ◽  
S. Ouahabi ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Satellite Imagery ◽  
Malaria Vector ◽  
Environmental Changes ◽  
Temporal Variations ◽  
Environmental Data ◽  
Transmission Risk ◽  
Cultivation Period ◽  
Very High

Malaria resurgence risk in Morocco depends, among other factors, on environmental changes as well as the introduction of parasite carriers. The aim of this paper is to analyze the receptivity of the Loukkos area, large wetlands in Northern Morocco, to quantify and to map malaria transmission risk in this region using biological and environmental data. This risk was assessed on entomological risk basis and was mapped using environmental markers derived from satellite imagery. Maps showing spatial and temporal variations of entomological risk for Plasmodium vivax and P. falciparum were produced. Results showed this risk to be highly seasonal and much higher in rice fields than in swamps. This risk is lower for Afrotropical P. falciparum strains because of the low infectivity of Anopheles labranchiae, principal malaria vector in Morocco. However, it is very high for P. vivax mainly during summer corresponding to the rice cultivation period. Although the entomological risk is high in Loukkos region, malaria resurgence risk remains very low, because of the low vulnerability of the area.

scholarly journals Effects of ultraviolet radiation on metabolic rate and fitness of Aedes albopictus and Culex pipiens mosquitoes

2018 ◽  
Author(s):  
Oswaldo C Villena ◽  
Bahram Momen ◽  
Joseph Sullivan ◽  
Paul T Leisnham
Keyword(s):  
Metabolic Rate ◽  
Microbial Communities ◽  
Aedes Albopictus ◽  
Culex Pipiens ◽  
Environmental Changes ◽  
Negative Impact ◽  
Transmission Rate ◽  
Major Effect ◽  
Control Group ◽  
Metabolic Rates

Environmental changes will alter many environmental factors in the coming years including temperature, precipitation, humidity, and the amount of solar radiation reaching the earth’s surface, which in turn will have an impact on living organisms like invertebrates. In this study, we assessed the effect of UV-B radiation upon the metabolic rate and upon three fitness parameters (survival, development time, and body size) of the mosquitoes Aedes albopictus and Culex pipiens, and upon the production of microbial resources on which mosquito larvae feed in aquatic microcosms. We set up three UV-B radiation treatments mimicking levels typically measured in full-sun (FS) and shade (S) conditions, as well as a control group with no UV-B radiation (NUV). The metabolic rate expressed as heat production (µwatts/ml) for larvae and microbial community was measured at days 1, 8, and 15. Our results indicated that UV-B radiation affected the metabolic rate of both Cx. pipiens and Ae. albopictus larvae; metabolic rates were significantly higher in full-sun (FS) compared to shade (S) and no-UV condition (NUV), at days 8 and 15 compared to day 1 (Figures 1A and 1B). Culex pipiens metabolic rates were significantly higher than Ae. albopictus at day 15 compared to days 1 and 8 (Figure 1B). Metabolic rates were significantly lower in microbial communities from vials with Ae. albopictus larvae, Cx. pipiens larvae, and no larvae in FS conditions compared to vials from S and NUV conditions, especially at day 8 (Figure 2A and 2B). There was a major effect of UV-B conditions only on the survival of Ae. albopictus and Cx. pipiens mosquitoes, with significantly lower survival in FS compared to S and NUV conditions. UV-B radiation at levels found in aquatic environments in open fields showed a negative impact on the metabolic rate of Ae. albopictus and Cx. pipiens larvae and on the microbial communities on which they feed. These negative impacts could have important implications for the distribution and abundance of these mosquitoes and for the transmission rate of illness caused by the pathogens that these two broadly distributed mosquitoes transmit.

scholarly journals Relationship of silver fir (Abies alba Mill.) mortality in the area of Fužine with climatic and structural parameters

2021 ◽  
Vol 145 (7-8) ◽  
pp. 311-321
Author(s):  
Damir Ugarković ◽  
Nenad Potočić ◽  
Marko Orešković ◽  
Krešimir Popić ◽  
Mladen Ognjenović ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Mortality ◽  
Negative Impact ◽  
Structural Parameters ◽  
Abies Alba ◽  
Extreme Weather Events ◽  
Anthropogenic Factors ◽  
Silver Fir ◽  
Weather Extremes ◽  
Causes Of Mortality

Tree dieback is a complex process involving negative impact of various abiotic, biotic and anthropogenic factors. Climate change, comprising all those effects, is generally considered as the largest threat to forest ecosystems in Europe. Although the scale of climate change impacts on forests is not yet fully understood, especially on the regional or species level, significant damage seems to be caused by weather extremes, such as drought and strong winds. With the expected increase in the number, length, and/or intensity of extreme weather events in Croatia, research into the causes of tree mortality is both important and timely. Silver fir is the most damaged and endangered conifer tree species in Croatia. The dieback of silver fir can be attributed to various factors, therefore the goals of this research were to determine the mortality of silver fir trees (by number and volume) for various causes of mortality, among which the climatic and structural parameters were of most interest. The twenty-year data for tree mortality in pure silver fir stands in the area of Fužine (Gorski kotar, Croatia) were collected and analysed. The largest number and volume of dead trees was caused by complex (multiple causes) dieback in the overstorey (0,75 N/ha, 2,35 m<sup>3</sup>/ha), and the smallest (0,17 N/ha, 0,02 m<sup>3</sup>/ha) by dieback of supressed trees. No significant differences were determined regarding the timing of tree death for different causes of mortality. Climatic parameters (drought, air temperature, PET) and structural parameters of the stands (tree DBH, social position, crown diameter, shading, physiological maturity) as well as plot inclination were found to be the factors of a significant influence on the mortality of silver fir trees.

scholarly journals Influence of soil fertility on waterlogging tolerance of two Brachiaria grasses

2015 ◽  
Vol 33 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Juan De la Cruz Jiménez ◽  
Juan Andrés Cardoso ◽  
David Arango-Londoño ◽  
Gerhard Fischer ◽  
Idupulapati Rao
Keyword(s):  
Soil Fertility ◽  
Nutrient Availability ◽  
Negative Impact ◽  
Nutrient Content ◽  
Soil Conditions ◽  
Soil Drainage ◽  
Waterlogging Tolerance ◽  
Waterlogged Soil ◽  
Fe And Mn ◽  
The Tropics

As a consequence of global warming, rainfall is expected to increase in several regions around the world. This, together with poor soil drainage, will result in waterlogged soil conditions. <em>Brachiaria</em> grasses are widely sown in the tropics and, these grasses confront seasonal waterlogged conditions. Several studies have indicated that an increase in nutrient availability could reduce the negative impact of waterlogging. Therefore, an outdoor study was conducted to evaluate the responses of two <em>Brachiaria</em> sp. grasses with contrasting tolerances to waterlogging, <em>B. ruziziensis </em>(sensitive) and <em>B. humidicola</em> (tolerant), with two soil fertility levels. The genotypes were grown with two different soil fertilization levels (high and low) and under well-drained or waterlogged soil conditions for 15 days. The biomass production, chlorophyll content, photosynthetic efficiency, and macro- (N, P, K, Ca, Mg and S) and micronutrient (Fe, Mn, Cu, Zn and B) contents in the shoot tissue were determined. Significant differences in the nutrient content of the genotypes and treatments were found. An increase of redoximorphic elements (Fe and Mn) in the soil solution occurred with the waterlogging. The greater tolerance of <em>B. humidicola</em> to waterlogged conditions might be due to an efficient root system that is able to acquire nutrients (N, P, K) and potentially exclude phytotoxic elements (Fe and Mn) under waterlogged conditions.  A high nutrient availability in the waterlogged soils did not result in an improved tolerance for <em>B. ruziziensis</em>. The greater growth impairment seen in the <em>B. ruziziensis</em> with high soil fertility and waterlogging (as opposed to low soil fertility and waterlogging) was possibly due to an increased concentration of redoximorphic elements under these conditions.

scholarly journals Spatial and Temporal Variations in Pigment and Species Compositions of Snow Algae on Mt. Tateyama in Toyama Prefecture, Japan

2021 ◽  
Vol 12 ◽  
Author(s):  
Tomomi Nakashima ◽  
Jun Uetake ◽  
Takahiro Segawa ◽  
Lenka Procházková ◽  
Akane Tsushima ◽  
...  
Keyword(s):  
High Performance ◽  
Algal Species ◽  
High Performance Liquid Chromatographic ◽  
Temporal Variations ◽  
Algal Community ◽  
Rrna Gene ◽  
Polar Regions ◽  
Dominant Type ◽  
Content Type ◽  
Snow Algae

Snow algae are photosynthetic microbes that inhabit the melting snow surface in alpine and polar regions. We analyzed the pigment and species composition of colored snow collected on Mt. Tateyama in Japan during the melting seasons of 2015 and 2016. High-performance liquid chromatographic analyses of the pigments extracted from the colored snow showed that their composition varied within the study area and were classified into four types: Type A (astaxanthin-monoester dominant), Type B (medium astaxanthin-monoester content), Type C (abundant primary carotenoids and free-astaxanthin), and Type D (abundant primary carotenoids and astaxanthin diesters). Types A and B were most commonly observed in the study area, whereas Types C and D appeared only at specific sites. Analysis of the 18S ribosomal RNA (18S rRNA) gene revealed six major amplicon sequence variants (ASVs) of snow algae, belonging to the Sanguina, Chloromonas, and Chlainomonas groups. The relative abundance of the algal ASVs showed that Sanguina was dominant (&gt;48%) in both Types A and B, suggesting that the difference in astaxanthin abundance between the two types was caused by the production of pigments in the algal cells. The algal community structures of Types C and D differed from those of Types A and B, indicating that the primary carotenoids and astaxanthin diesters were derived from certain algal species in these types. Therefore, astaxanthin-rich Sanguina algae mostly induced the red snow that appeared widely in this alpine area; however, they were partially dominated by Chloromonas or Chlainomonas algae, causing different pigment compositions.

scholarly journals THE IMPACT OF EU STRUCTURAL FUND SUPPORT AND PROBLEMS OF ITS ABSORPTION

2013 ◽  
Vol 11 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Daiva Jurevičienė ◽  
Jūratė Pileckaitė
Keyword(s):  
National Economy ◽  
Direct Investment ◽  
Statistical Data ◽  
Negative Impact ◽  
Structural Fund ◽  
Economic Activities ◽  
Structural Support ◽  
Short Period ◽  
The Impact ◽  
Eu Support

Targeted allocation of EU support in Lithuania can help resolving a number of problems and achieving significant results in a variety of areas. However, rush to absorb support may lead to a little, zero or even negative impact on national economy. In addition, EU support opportunities may distort investment motivation. This paper deals with issues related to the impact of EU support and problems of its absorption. The impact of EU support on the national economy has been established in three areas: attraction of foreign direct investment state investments into capital formation, and experience of companies, which are EU support beneficiaries. The paper proposes using regression analysis in search and evaluation of relations while obtaining more information about programmes, priorities and the impact of structural support on different indicators. In addition, it focuses on ascertaining the effectiveness of governmental and company spending. Furthermore, as companies – EU support beneficiaries – are engaged in different economic activities, their experience cannot be ascertained from statistical data; consequently, findings of an expert survey are presented to demonstrate the experience acquired by business companies as well as problems they face. Limitation of research was a short period of time to evaluate (only four years of the current funding period)

Impact of Climate Change on Rural Livelihood: A Case Study of Central Rajasthan

2021 ◽  
Vol 7 (4) ◽  
pp. 19-27
Author(s):  
Saifuddin Soz ◽  
Dhananjay Mankar
Keyword(s):  
Climate Change ◽  
Negative Impact ◽  
Extreme Weather Events ◽  
Household Level ◽  
Impact Of Climate Change ◽  
The People ◽  
Weather Events ◽  
Rural Livelihood ◽  
The Pacific ◽  
The Impact

Climate change is already bringing tremendous influence on people’s lives, particularly the underprivileged. It’s already visible in a variety of ways. In recent decades, Asia and the Pacific have seen consistent warming trends as well as more frequent and powerful extreme weather events such as droughts, cyclones, floods, and hailstorms. This study was done in Ajmer District of Rajasthan, to find out the climate variation in the last 10 years. The study describes the effects due to climate change on the livelihoods of the people, so a descriptive research design was used for the study to find out the impact of climate change on rural livelihood in central Rajasthan. The study is based on a large representative of sample, quantitative data was collected to gain an idea of the impact on the livelihoods due to climate change at the household level. It shows the negative impact of climate change on rural livelihood which forced the people to change their livelihood directly or indirectly. It was found that climate change had an impact on people’s lives and people do understand the variation in climate change in terms of changes in the weather, unseasonal rain, and drought.

Managing the Dynamic Reconfiguration of Enterprises

2010 ◽  
pp. 387-397
Author(s):  
Ben Clegg ◽  
Mario Binder
Keyword(s):  
Joint Ventures ◽  
Environmental Changes ◽  
Core Competencies ◽  
Enterprise Management ◽  
Economic Activities ◽  
Collaborative Relationships ◽  
Member Company ◽  
Internal Core ◽  
Value Streams ◽  
Definition Of

Due to environmental changes and business trends such as globalisation, outsourcing and virtualisation, more and more companies get involved in business activities that are outside their direct control. This typically occurs by entering into collaborative relationships and joint ventures with specialised companies in order to fulfil the demands of customers quickly (DiMaggio, 2001). Organisational structures that results from such collaborative relationships and joint ventures are referred to in this paper as enterprises and the management of them known as enterprise management. The authors use the definition of the European Commission (2003) that defines an enterprise as “… an entity, regardless of its legal form … including partnerships or associations regularly engaged in economic activities.” Therefore in its most simple form an enterprise could be a single integrated company. However, findings from this research show that enterprises can also be made up of parts of different companies and the structure of the enterprise is contingent upon a variety of different factors. The success of the enterprise as a collaborative venture depends on the ability of companies to intermediate their internal core competencies into other participating companies’ value streams and simultaneously outsource their own peripheral activities to companies that can perform them quicker, cheaper, and more effectively (Lal et al., 1995). In other words, the peripheral activities of one member-company must be complemented by a core competence of another member-company within an overall enterprise.

Sign in / Sign up

Export Citation Format

Share Document