Dinamica stagionale e distribuzione orizzontale di fitoplancton, carbonio organico e batterioplancton. Struttura dei popolamenti fitoplanctonici

No abstract availabl

Dinamica stagionale e distribuzione orizzontale di fitoplancton, carbonio organico e batterioplancton. Struttura dei popolamenti fitoplanctonici

No abstract availabl

Indagini limnologiche nell\u27area antistante la Foce del Torrente San Bernardino (Sopralluoghi del 18-20 aprile 2011)

No abstract availabl

Indagini limnologiche nell\u27area antistante la foce del Torrente San Bernardino (sopralluogo del 14 giugno 2010)

No abstract availabl

Indagini limnologiche nell\u27area antistante la foce del Torrente S. Bernardino (sopralluogo del 26 Ottobre 2010)

No abstract availabl

The chemical and biological response of two remote mountain lakes in the Southern Central Alps (Italy) to twenty years of changing physical and chemical climate

Two small high mountain lakes in the Alps were monitored in 1984-2003 to follow their response to changes in human impact, such as deposition of atmospheric pollutants, fish stocking and climate change. The results were compared to occasional samplings performed in the 1940s, and to the remains found in sediment cores. When monitoring started, the most acid-sensitive of them, Lake Paione Superiore, was acidified, with evident effects in its flora and fauna: benthic diatoms assemblage was shifted towards aci- dophilous species, and zooplankton lost the dominant species, Arctodiaptomus alpinus. Palaeolimnological studies outlined that lake acidification paralleled the increasing input of long-range transported industrial pollutants, traced by spherical carbonaceous parti- cles. On the contrary, the biota of Lake Paione Inferiore appeared to be mainly affected by fish stocking. In the last twenty years, de- crease in acid load from the atmosphere led to an improvement in lake water quality, with an increase in both pH and alkalinity. First signs of biological recovery were identified, such as change in diatom flora and appearance of sensitive species among benthic insects. However, climate change and episodic deposition of Saharan dust were important driving factors controlling lake water chemistry. Further monitoring to assess the effects of climate change and of the increasing load of nitrogen and other pollutants is recommended. Key word: atmospheric deposition, acidification, plankton, benthos, diatom

Recent dynamics (1995-1999) of the phytoplankton assemblages in Lago Maggiore as a basic tool for defining association patterns in the Italian deep lakes

The main goal of the study presented here is to identify a repeatable pattern in the seasonal succession of phytoplankton assemblages in Lago Maggiore. In order to fulfil this objective we analysed the phytoplaktonic succession during a five years period (1995-1999), through the calculation of the Bray-Curtis similarity index applied to biovolume data. A cluster analysis has been then applied to the distance matrix, allowing the identification of sample clusters possessing a similar species composition. The comparison, through the whole period considered, of the phytoplankton assemblages characterising each cluster allowed to recognise six seasonal periods (Winter, Early Spring, Late Spring, Early Summer, Late Summer, Autumn), each of them characterised by a peculiar and repeatable species assemblage. Among the most interesting findings we would mention the existence of a Late Spring/Early Summer association, dominated by Planktothrix rubescens and Fragilaria crotonensis, probably peculiar of the deep subalpine lakes, where these species can better take advantage of the physical and chemical environment of the metalimnetic niche. The identification of a pool of dominant and sub-dominant species common to other southern subalpine lakes and the existence of a similar time periodicity in the development and decline of most of them across this lake district seem to be promising in order to give our results a wider application

Indagini sull\u27ambiente pelagico. Popolamenti planctonici. Indagini sul fitoplancton

No abstract availableStruttura dei popolamenti e variazioni della biomass