Search results for " Lakes"

Water quality in cutaway peatland lakes in Seda mire, Latvia

2011

Remediation of industrially-milled peatland is an important task in the sustainable management of natural resources. Several approaches for wetland restoration, depending on local climatic and hydrological conditions, topography, physico-chemical properties of peat, as well as peat mining techniques, have been developed worldwide. However, most of the restoration activities include regulation of hydrological regime and surface topography in order to reintroduce typical bog vegetation, especially, Sphagnum cover, and to restore the peatland’s ecosystem close to its original conditions (Gorham and Rochefort, 2003; Farrell and Doyle, 2003; Lamers et al., 2002). In many countries, a significant…

On the Choice of the Most Suitable Period to Map Hill Lakes via Spectral Separability and Object-Based Image Analyses

2023

Technological advances in Earth observation made images characterized by high spatial and temporal resolutions available, nevertheless bringing with them the radiometric heterogeneity of small geographical entities, often also changing in time. Among small geographical entities, hill lakes exhibit a widespread distribution, and their census is sometimes partial or shows unreliable data. High resolution and heterogeneity have boosted the development of geographic object-based image analysis algorithms. This research analyzes which is the most suitable period for acquiring satellite images to identify and delimitate hill lakes. This is achieved by analyzing the spectral separability of the su…

The unnoticed northward expansion of Najas marina subsp. armata (Hydrocharitaceae) in the Mediterranean area: an effect of climate change?

2022

Recent reports of Najas marina L. (Hydrocharitaceae) from Sicily have been interpreted as a confirmation of its presence on the island, where it was earlier mentioned in the 1800s. However the recent finds do not represent “N. marina” (currently N. major All.) but N. marina subsp. armata Horn (= N. delilei Rouy), a different taxon, previously not recorded from Sicily. According to those reports and several new finds presented here, it appears to be invading reservoirs and lakes in southern Sicily and seems to be naturally expanding its range. Climate change is suggested as possible cause of this shift. The same trend appears to be taking place across the whole N Mediterranean area, from Por…

Phytoplankton assemblages in twenty-one Sicilian reservoirs: relationships between species composition and environmental factors

2000

Data collected in a limnological survey, carried out between 1987 and 1988 on 21 Sicilian reservoirs of varying trophic state, were ordinated using CANOCO 3.1 to generalise the way in which the structure of phytoplankton assemblage is conditioned by both physical and chemical variables. The results showed that in these man-made lakes, characterised by conspicuouswater-level fluctuations, the annual and interannual variability in the abundance and composition of phytoplankton may be strongly influenced by their peculiar hydraulic regimes rather than by nutrient availability. In particular, it was highlighted that, from the early summer, water abstraction often leads to increased circulation …

Climate change and enhancement of water-level fluctuations in Mediterranean reservoirs: a sad fate for water quality?

2010

Tipologica ambiental de los sistemas leniticos de Huinay (Decima Region de Los Lagos, Chile) y distribucion del plancton limnico

2010

Mapping phycocyanin cells density of Planktothrix rubescens in freshwater reservoirs

2014

SMALL LAKES AND RESERVOIRS IN THE HILLS OF SICILY. MAINTAIN, SAVE AND RECOVER RURAL LANDSCAPE

2011

In the transition from nomadic to sedentary, people have tried - for their settlements - the most plenty of water, and the first cities were founded, in fact, along Tigris and Euphrates rivers, extraordinary water resources in a particular dry climate. In the most interior of Sicily, which has always been characterized by low rainfall, the farmers - over time - have tried various expedients for the preservation of rain water in order to allow its survival and crop. The use of new technologies and materials has resulted in recently hard impacts for landscape, while construction of small dams filled with earth, using natural soil impluviums and the nature of the land, made it possible to irri…

Heterogeneous vertical structure of the bacterioplankton community in a non-stratified Antarctic lake

2013

10 páginas, 4 figuras, 2 tablas.

Invasive vascular plant species of oxbow lakes in south-western Poland

2015

Abstract Natural water reservoirs are very valuable floristic sites in south-western Poland. Among them, the most important for the preservation of biodiversity of flora are oxbow lakes. The long-term process of human pressure on habitats of this type caused disturbances of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of the last two hundred years, led to systematic disappearances of localities of many plant species connected with rare habitats and also to the appearance of numerous invasive plant species. They are: Azolla filiculoides, Echinocystis lobata, Erechtites hieraciifolia, Impatiens glandulif…