Refinar búsqueda
Resultados 1-10 de 14
Hydraulic structures and quality of water as a biotope in ecosystem
2001
Batinic, B. | Jovanovic, B. (Univerzitet u Beogradu, Beograd (Yugoslavia). Gradjevinski fakultet)
This paper points out the role and significance of civil engineering in dealing with the problems related to the water environment. Examples presented consider hydraulic structures and their impact on the aeration level in the watercourse. Aeration and reaeration have the most important effect on the oxygen water quality parameters and therefore on the entire living world in the particular ecosystem.
Mostrar más [+] Menos [-]Crohn’s disease and environmental contamination: Current challenges and perspectives in exposure evaluation
2020
Tenailleau, Quentin M. | Lanier, Caroline | Gower-Rousseau, Corinne | Cuny, Damien | Deram, Annabelle | Occelli, Florent
Although the incidence of Crohn’s disease has increased worldwide over the past 30 years, the disorder’s exact causes and physiological mechanisms have yet to be determined. Given that genetic determinants alone do not explain the development of Crohn’s disease, there is growing interest in “environmental” determinants. In medical science, the term “environment” refers to both the ecological and social surroundings; however, most published studies have focused on the latter. In environmental and exposure sciences, the term “environment” mostly relates to contamination of the biotope. There are many unanswered questions on how environmental hazards might contribute to the pathogenesis of Crohn’s disease. Which pollutants should be considered? Which mechanisms are involved? And how should environmental contamination and exposure be evaluated? The objective was to perform a systematic review of the literature on Crohn’s disease and environmental contamination. We searched the PubMed, Google Scholar, Scopus, ISI Web of Science and Prospero databases. We considered all field studies previous to April 2019 conducted on human health indicators, and evaluating exposure to all type of physical, biological and chemical contamination of the environment. The lack of clear answers to date can be ascribed to the small total number of field studies (n = 16 of 39 publications, most of which were conducted by pioneering medical scientists), methodological differences, and the small number of contaminants evaluated. This make it impossible to conduct a coherent and efficient meta-analysis. Based on individual analysis of available studies, we formulated five recommendations on improving future research: (i) follow up the currently identified leads - especially metals and endocrine disruptors; (ii) explore soil contamination; (iii) gain a better knowledge of exposure mechanisms by developing transdisciplinary studies; (iv) identify the most plausible contaminants by developing approaches based on the source-to-target distance; and (v) develop registries and cohort-based analyses.
Mostrar más [+] Menos [-]Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments
2017
Zimmermann, Sonja | Wolff, Carolina | Sures, Bernd
Mainly due to automobile traffic, but also due to other sources, the platinum group elements (PGE) platinum (Pt), palladium (Pd) and rhodium (Rh) are introduced into aquatic biotopes where they accumulate in sediments of lakes and rivers. However, the toxicity of these noble metals to aquatic organisms is not well understood and especially toxicity studies under standardized condition are lacking. Thus, the toxicity of Pt, Pd and Rh to Daphnia magna was tested in single metal exposure experiments according to OECD guideline 202. Immobility and lethality was recorded after 24 h and 48 h of exposure and EC50 and LC50, respectively, were determined. As the nominal exposure concentration of Pd differed significantly from the quantified concentration, the control of the real exposure concentration by chemical analysis is mandatory, especially for Pd.The toxicity decreased in the order Pd > Pt ≫ Rh with e.g. LC50(48 h) values of 14 μg/L for Pd, 157 μg/L for Pt and 56,800 μg/L for Rh. The exposure period had a clear effect on the toxicity of Pt, Pd and Rh. For Pt and Rh the endpoint immobility was more sensitive than the endpoint lethality whereas Pd toxicity was similar for both endpoints. The Hill slopes, which are a measure for the steepness of the concentration-response curves, showed no significant discrepancies between the different metals.The binary metal exposure to Pt and Pd revealed a more-than-additive, i.e. a synergistic toxicity using the toxic unit approach. The present study is a start to understand the toxicity of interacting PGE. The modes of action behind the synergistic effect are unclear.
Mostrar más [+] Menos [-]Benthic surveys of the historic pearl oyster beds of Qatar reveal a dramatic ecological change
2016
Smyth, D. | Al-Maslamani, I. | Chatting, M. | Giraldes, B.
The study aimed to confirm the presence of historic oyster banks of Qatar and code the biotopes present. The research also collated historical records and scientific publications to create a timeline of fishery activity. The oyster banks where once an extremely productive economic resource however, intense overfishing, extreme environmental conditions and anthropogenic impacts caused a fishery collapse. The timeline highlighted the vulnerability of ecosystem engineering bivalves if overexploited. The current status of the oyster banks meant only one site could be described as oyster dominant. This was unexpected as the sites were located in areas which once supported a highly productive oyster fishery. The research revealed the devastating effect that anthropogenic impacts can have on a relatively robust marine habitat like an oyster bed and it is hoped these findings will act as a driver to investigate and map other vulnerable habitats within the region before they too become compromised.
Mostrar más [+] Menos [-]Verifying a biotope classification using benthic communities – An analysis towards the implementation of the European Marine Strategy Framework Directive
2014
Schiele, Kerstin S. | Därr, Alexander | Zettler, Michael L.
The HELCOM Red List biotopes project proposed a Baltic Sea wide classification consisting of six levels: The HELCOM Underwater biotopes/habitats classification system (HELCOM HUB). We present a case study from the south-western Baltic Sea where we tested the applicability of this system. More than 500 sampling stations were analyzed regarding macrozoobenthic communities and their linkage to environmental parameters. Based on the analyses of biotic and abiotic data, 21 groups were assigned to 13 biotopes of the classification. For some biotopes varying states of communities were recognized. Even though not all abiotic parameters are considered directly in the hierarchy of the classification in general, all soft-bottom communities could be allocated to a corresponding biotope. The application of the HELCOM HUB for the south-western Baltic Sea is feasible, in regard to the implementation of the European Marine Strategy Framework Directive as well as the Baltic Sea Action Plan.
Mostrar más [+] Menos [-]An approach based on M-AMBI for assessing benthic ecological status of a broad intertidal zone: A case study in the Jiangsu intertidal zone, China
2017
Song, Qiaochu | Zou, Xinqing | Zhang, Hu | Yu, Wenwen | Zang, Zheng | Wang, Chenglong
Intensive anthropogenic activities have a serious negative effect on the Jiangsu coastal area of China, especially on the distinctive intertidal zone. Humans are trying to eliminate this effect by taking protection and eco-compensation measures. However, when trying to determine the ecological status and quantify the anthropogenic impact for this area, the complex relationship between ecosystems and environmental stress leads to difficulties in reflecting general environmental quality. This study assessed the benthic ecological status of 10 transects (three stations/transect) across six different typologies over six years (2007, 2009–2013) in the Jiangsu intertidal zone. A unitary assessment of each transect was conducted using the multivariate AZTI Marine Biotic Index (M-AMBI), along with a radar chart (and its parameters). In the Jiangsu intertidal zone, the ecological status was noted as good or moderate at most sampling stations. Among the six assessed years, 2010 had the highest ecological status, while 2007 had the lowest. As for transects, transect 1 had the highest ratings, and transect 3 had the lowest ratings. Various stresses and advantageous human intervention and contributed to the ecological status for the different areas. The M-AMBI could be used in the future as a suitable index to assess the benthic ecological status of the Jiangsu intertidal zone. In addition, the new unitary method validated in this study could be used to assess ecosystems with several small biotopes, while accurately reflecting environmental quality.
Mostrar más [+] Menos [-]Predation mechanisms of Rapana venosa (Gastropoda: Muricidae) in different biotopes along the Black Sea coast
2016
Kosyan, Alisa
Mechanisms of feeding by the invasive gastropod Rapana venosa from different biotopes of 11 sites along the Black Sea coast are discussed. Two methods – edge-drilling and suffocation – are used, but the prevailing method in a particular biotope depends on the type of bivalve prey. Drill signs were present on almost all shells of Chamelea gallina, captured by rapa whelks in field conditions, while in a field experiment, only 11% of all empty Mytilus galloprovincialis had drilling signatures. The degree of radula abrasion was also dependent on the available bivalves: it was the highest in biotopes with C. gallina and juvenile mussels, and the lowest in biotopes with large mussels. Intermediate degrees of abrasion were observed in biotopes with mixed prey: C. gallina and Anadara kagoshimensis, C. gallina and mussels, or small and large mussels. Since we observed only initial signs of drilling, simultaneous application of boring and suffocation could take place.
Mostrar más [+] Menos [-]Utilizing benthic foraminifera to explore the environmental condition of the Laizhou Bay (Bohai Sea, China)
2021
Donnici, Sandra | Serandrei-Barbero, Rossana | Gao, Xuelu | Tang, Cheng | Tosi, Luigi
Through the analysis of benthic foraminifera in the soft bottom sediments of the Laizhou Bay – Yellow River Delta system, this study characterized the foraminiferal biotopes and explored the possibility of obtaining an index of ecological quality comparable with other estuarine and coastal environments of the world. Five foraminiferal biotopes have been identified and their distribution patterns highlight the ecological stress from the marine-fluvial water mixing and pollution. The foraminiferal species were analyzed as a function of organic carbon gradients, and the main species were assigned to four ecological groups based on their sensitivity/tolerance towards an increasing stress gradient. Finally, the relative proportions of the species assigned to the four different ecological groups were used for the definition of a marine biotic index based on foraminifera, i.e. the Foram-AMBI, and thus the assessment of the ecological quality status of marine soft-bottom habitats.
Mostrar más [+] Menos [-]Biotope map of the German Baltic Sea
2015
Schiele, Kerstin S. | Därr, Alexander | Zettler, Michael L. | Friedland, René | Tauber, Franz | von Weber, Mario | Voss, Joachim
Full-coverage maps on the distribution of marine biotopes are a necessary basis for Nature Conservation and Marine Spatial Planning. Yet biotope maps do not exist in many regions. We are generating the first full-coverage biotope map for the German Baltic Sea according to the HELCOM Underwater biotope and habitat classification system (HUB). Species distribution modelling is applied to create full-coverage spatial information of biological features. The results of biomass modelling of twelve target taxa and presence/absence modelling of three target taxa enabled the identification of biological levels up to HUB level 6. Environmental data on bathymetry, light penetration depth and substrate are used to identify habitat levels. HUB biotope levels were combined with HUB habitat levels to create a biotope map. Altogether, 68 HUB biotopes are identified in the German Baltic Sea. The new biotope map combining substrate characteristics and biological communities will facilitate marine management in the area.
Mostrar más [+] Menos [-]Are there correlations between the levels of fluctuating asymmetry in Pelophylax ridibundus (Anura: Ranidae) meristic morphological traits and morphological parameters used for assessing their physical fitness (health status)?
2022
Zhelev, Zhivko | T︠S︡onev, Stefan | Mollov, Ivelin
The degree of developmental stability of individuals and populations is most often estimated by their level of fluctuating asymmetry (FA) — the random deviations from perfect symmetry. In our previous work, we recorded high levels of FA (FAMI index: frequency of asymmetric manifestation of an individual) in Pelophylax ridibundus populations that inhabit biotopes at Sazliyka River, south Bulgaria with high levels of anthropogenic pollution (domestic sewage pollution). At the same time, in the biotopes located in the upper reaches of the river (less disrupted habitats), the populations showed low levels of FA. Currently, we present the results of the study of the values of several morphological parameters: snout-vent length (SVL), body weight (BW), and body condition factor (CF) in the same populations of P. ridibundus. In addition, we evaluate the correlation between the values of these morphological parameters and the values of fluctuating asymmetry (the FAMI index), using the Kendall rank correlation analysis. The analysis of the relationships between the parameters characterizing the physical fitness of frogs and the indicator of developmental stability — the FAMI index — did not establish statistically significant correlations in the analyses in the whole groups of P. ridibundus from each site and in the correlations between sexes. We believe that the approaches to the study of developmental stability (analysis of fluctuating asymmetry levels) and those related to the assessment of physical fitness (health status) of frogs should be applied independently of each other.
Mostrar más [+] Menos [-]