Biotests in Ecotoxicology: Current Practice and Problems

Nowadays ecotoxicology plays the role of a theoretician – methodical unifying centre for the optimization of man – biosphere relations and sustainable existence of life on the Earth. The main basis for its development is the classical toxicology—studies of chemical compounds’ effects on man, but ecotoxicology is the original part, following it. According to the modern concept, the ecotoxicology is a science for migration, transformation and utilization of different toxic ingredients (with organic, inorganic or organic-mineral chemical nature; with natural biotic or abiotic origin and artificial, mainly anthropogenic origin) in the environment and their impact on Macro- biological systems with different levels of integration as groups of individuals, population, community, ecosystem, etc. studied in ecology. In this chapter, the types of ecotoxicological tests are discussed in detail with a set of examples about used species, advantages and disadvantages of different types of toxicity testing. The application of exposed natural ecosystems or man-made analogue systems is also commented as the environmentally more realistic approach for ecotoxicological testing. These test systems are increasingly becoming in aquatic ecotoxicology practice, but they are contemporary challenge in terrestrial testing. The development of test systems for realistic assessment of contaminant toxicity is essential for the efficient control of human influence on the environment

Quantitative Analysis of Different Environmental Factor Impacts on Land Cover in Nisos Elafonisos, Crete, Greece

Land Cover monitoring is an essential task for a better understanding of the ecosystem’s dynamicity and complexity. The availability of Remote Sensing data improved the Land Use Land Cover mapping as it is routine work in ecosystem management. The complexity of the Mediterranean ecosystems involves a complexity of the surrounding environmental factors. An attempt to quantitatively investigate the interdependencies between land covers and affected environmental factors was conducted in Nisos Elafonisos to represent diverse and fragile coastal Mediterranean ecosystems. Sentinel-2 (MSI) sensor and ASTER Digital Elevation Model (DEM) data were used to classify the LULC as well as to draw different vegetation conditions over the designated study area. DEM derivatives were conducted and incorporated. The developed methodology is intended to assess the land use land cover for different practices under the present environmental condition of Nisos Elafonisos. Supervised classification resulted in six different land cover clusters and was tested against three different environmental clusters. The findings of the current research pointed out that the environmental variables are independent and there is a vertical distribution of the vegetation according to altitude

Distribution of microbial abundance in long-term copper contaminated soils from Topolnitsa-Pirdop valley, Southern Bulgaria

This study presents the distribution of bacterial and fungal abundances in long-term copper (Cu) contaminated soils in Topolnitsa-Pirdop valley – a highly industrialized zone with a number of mines and processing plants for copper and other non-ferrous metals. The bacterial (16S rRNA gene copies) and fungal (ITS rRNA gene copies) were estimated using quantitative PCR technique in five topsoils, differently Cu contaminated (ranging from 28.05 to 198.9 mg kg-1). Bacterial abundance varied in a range of 1.68 × 1011 to 3.24 × 101116S rRNA genes, whereas fungi amounted from 1.95 × 108 to 6.71 × 108 ITS rRNA genes. Fungal and bacterial abundances were significantly (fungi) and insignificantly (bacteria) influenced by Cu contamination. The fungal/bacterial ratio related negatively with soil Cu, which shifted microbial communities’ structure towards bacterial dominance. Since the ratio between bacteria and fungi are vital in explaining many soil functions, the calculated changes in this ratio indicated deterioration in soil quality, being of primary importance for plant production

Correlation between bacterial abundance, soil properties and heavy metal contamination in the area of non-ferrous metal processing plant, Southern Bulgaria

In the present study, the correlation between bacterial abundance and soil physicochemical properties along the heavy metal contamination gradient in the area of non-ferrous metal processing plant was assessed. Our results showed that bacterial abundance (number of heterotrophic bacteria and number of 16S rRNA gene copies) decreased with 45–56% (CFU) and 54–87% (16S rRNA gene) along the Zn, Pb and Cd contamination gradient. The total bacterial abundance (16S rRNA gene) increased exponentially in contrast to the abundance of heterotrophic bacteria. The reduction of bacterial abundance in heavily contaminated soil indicated that the soil properties (soil pH, total organic carbon, inorganic ions, soil texture) could modify the effects of heavy metals and the response of microorganisms to that stress in long-term contaminated soils

Differences in bacterial functional profiles from loamy sand and clay loam textured soils under fungicide QuadrisR impact

The non-target effect of the fungicide QuadrisR on the bacterial community from grassland loamy sand (LS) and cropland clay loam (CL) soils with unknown history of fungicide usage was investigated. QuadrisR was applied to soil mesocosms at 0.0 mg kg-1 (Az0), 2.90 mg kg-1 (Az1), 14.65 mg kg-1 (Az2) and 35.0 mg kg-1 (Az3) calculated towards the active ingredient azoxystrobin (Az). Response of bacterial communities to QuadrisR was investigated during a 120-day incubation experiment, evaluating the shifts in bacterial catabolic profiles by the community-level physiological profiling (CLPP) technique and Biolog EcoPlatesTM method. QuadrisR decreased the overall catabolic activity (AWCD) of soil bacterial communities and the rate of decrease was independent of soil type and fungicide concentration. Fungicide affected negatively the utilisation of amines and positively that of amino acids in both soil types, whereas the effects on other carbon guilds (carbohydrates, carboxylic acids and polymers) corresponded closely to the respective soil type and fungicide concentration. Results indicated the presence of non-target effects of QuadrisR on bacterial functioning; hence, it is important to address the fungicide side-effects on soil health

Monitoring of mangrove forests vegetation based on optical versus microwave data: A case study western coast of Saudi Arabia

Normalized difference vegetation index (NDVI) is one of the parameters of vegetation that can be studied by remote sensing of land surface with Sentinel-2 (S-2) satellite image. The NDVI is a nondimensional index that depicts the difference in plant cover reflectivity between visible and near-infrared light and can be used to measure the density of green on a piece of land. On the other hand, the dual-pol radar vegetation index (DpRVI) is one of the indices studied using multispectral synthetic aperture radar (SAR) images. Researchers have identified that SAR images are highly sensitive to identify the buildup of biomass from leaf vegetative growth to the flowering stage. Vegetation biophysical characteristics such as the leaf area index (LAI), vegetation water content, and biomass are frequently used as essential system parameters in remote sensing data assimilation for agricultural production models. In the current study, we have used LAI as a system parameter. The findings of the study revealed that the optical data (NDVI) showed a high correlation (up to 0.712) with LAI and a low root-mean-square error (0.0296) compared to microwave data with 0.4523 root-mean-square error. The NDVI, LAI, and DpRVI mean values all decreased between 2019 and 2020. While the DpRVI continued to decline between 2020 and 2021, the NDVI and LAI saw an increase over the same period, which was likely caused by an increase in the study area’s average annual rainfall and the cautious stance of the Red Global (RSG) project on sustainability