Search results for "ECOSYSTEM"

Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to t…

2013

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…

Global distributions of diazotrophs nitrogen fixation rates - Depth integrated values computed from a collection of source datasets - Contribution to…

2013

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…

Climate change and cyclic predator-prey population dynamics in the high Arctic.

2009

The high Arctic has the world's simplest terrestrial vertebrate predator–prey community, with the collared lemming being the single main prey of four predators, the snowy owl, the Arctic fox, the long-tailed skua, and the stoat. Using a 20-year-long time series of population densities for the five species and a dynamic model that has been previously parameterized for northeast Greenland, we analyzed the population and community level consequences of the ongoing and predicted climate change. Species' responses to climate change are complex, because in addition to the direct effects of climate change, which vary depending on species' life histories, species are also affected indirectly due to…

Geological development of a gypsum lake formed at the beginning of the 20th century in central Sicily, Italy: Integration of historical data with mod…

2006

A limnological investigation was carried out on the small, endorheic lake, called Lake Sfondato, located in central Sicily (Italy). All the aquatic environments in the central part of the island are rich in salt, with conductivity values above 5 mS cm−1, and are characterized by high alkalinity values and hard waters. In addition, due to intensive agriculture, many of these ecosystems have experienced a strong anthropogenic eutrophication over the last decades. In order to better understand the functioning of these peculiar environments, the morphology, hydrology, and geochemistry, as well as several selected physical and biological characteristics of Lake Sfondato, were studied in the year…

Advanced analytical techniques based on high-resolution mass spectrometry for the detection of micropollutants and their toxicity in aquatic environm…

2020

Abstract An abundance of micropollutants (MPs) in treated wastewater (WW) and occasionally even in drinking water represents a global threat from the environmental and public health risk standpoint. Along with the development of innovative WW treatment technologies, advanced analytical techniques, such as chromatography hyphenated to high-resolution mass spectrometry, are required for ensuring the detectability of target and nontarget MPs. Further studies on the chronic toxicity of MPs are needed to improve the regulation of hazardous substances in WWs. This article provides an up-to-date overview of the latest methodological developments related to the screening and quantification of MPs, …

Acute lethal toxicity of some pesticides toBrachionus calyciflorus andBrachionus plicatilis

1991

Due to their widespread distribution and toxic nattwe pesticides may have a serious impact on the aquatic environment and exert adverse effects on the associated organisms. Acute bioassay tests have been used to determine the actual impact of various pesticides on aquatic life. Static acute toxicity tests provide rapid and reproductible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a data base for determining relative toxicity to a variety of species.

Genetic variation of European beech (Fagus sylvatica L.) along an altitudinal transect at mount Vogelsberg in Hesse, Germany

2000

Allelic and genotypic variation at 13 different enzyme loci of autochthonous European beech (Fagus sylvatica L.) was investigated in six 110-160-year-old stands growing at elevations between 150 and 660 m above sea level on the western slope of mount Vogelsberg in central Germany. The highest elevated population showed the highest number of effective alleles (Ne), the highest total heterozygosity (He) and the highest population differentiation deltaT. Also, the genotype SKD-A2A3 of shikimate dehydrogenase was significantly more frequent at the two highest elevated stands (P = 11%) than at the three lowest elevated stands (P = 1%). Further differences in genotype frequencies between 11 of 15…

Rīgas līča un Baltijas jūras zooplanktona daudzgadīgā dinamika un to kontrolējošie vides faktori

2005

Wide-scope screening of pharmaceuticals, illicit drugs and their metabolites in the Amazon River.

2021

Only a limited number of households in the Amazon are served by sewage collection or treatment facili- ties, suggesting that there might be a significant emission of pharmaceuticals and other wastewater contaminants into freshwater ecosystems. In this work, we performed a wide-scope screening to assess the occurrence of pharmaceuticals, illicit drugs and their metabolites in freshwater ecosystems of the Brazilian Amazon. Our study included 40 samples taken along the Amazon River, in three of its major tributaries, and in small tributaries crossing four important urban areas (Manaus, Santarém, Macapá, Belém). More than 900 compounds were investigated making use of target and suspect screenin…

Historical Landscape Ecology of the Favorita Park in Palermo (Sicily)

2021

Historical Landscape Ecology of the Favorita Park in Palermo