We present the results of a four-years monitoring program of Lake Duchessa, a small shallow subalpine lake situated at 1788 m a.s.l. in central Apennines (Italy). From 1997 to 2000, during snow free periods, we regularly measured conductivity, pH, macrophyte cover and water transparency. Contemporarily, 4 water samples were collected to determine nutrient (NH3-N, NO2N, NO3-N and PO4-P) and phytoplanktonic chlorophyll a concentrations. Taxonomic compositions of aquatic macrophytes, zooplankton and macroinvertebrates were also determined. Inter- and intra-annual variation of water chemistry and phytoplankton biomass were addressed. Lake Duchessa showed some limnological aspects proper to lowland eutrophic situations due to livestock grazing in the watershed pastures and watering in the lake. In particular, nutrient concentration and phytoplankton biomass reached extremely high values, and lake community was relatively poor. However, despite the high nutrient loading, phytoplankton biomass collapsed in August 1997. In the same occasion, lake water became transparent and remained clear until the end of 1999. The occurrence of this clear water phase and its surprising span may be related to the reduction of tench population (due to a natural fish kill observed during the study) and to the extension of Potamogeton pectinatus L. and Myriophyllum spicatum L. cover. Our results support early observations that water transparency (i.e. environmental quality) of eutrophic shallow lakes can be improved also when nutrient loading is not reduced. Many of the Apennine lakes and ponds situated at high altitudes show conditions similar to those of Lake Duchessa. Therefore this study highlights the ecological processes to be considered in a reliable management of these freshwater systems.

The assemblage patterns of pelagic Cladocera species were investigated in a meso-eutrophic reservoir from January 2000 to December 2002. Trends of environmental factors (water temperature, conductivity, pH, and nutrient concentrations), as well as of biotic factors (availability of potentially edible phytoplankton and densities of herbivorous and carnivorous copepods) were assessed. Zooplankton community was dominated by Cladocera and Copepoda. Assemblage patterns for Cladocera were identified by performing a cluster analysis on abundance data of the dominant species: Daphnia longispina, Ceriodaphnia pulchella, Bosmina longirostris and Diaphanosoma brachyurum. In winter and spring, Daphnia was dominant. In early summer and end of autumn, Ceriodaphnia and Daphnia coexisted. During summer, Ceriodaphnia was dominant and coexisted with Diaphanosoma. Bosmina was present in low densities during the whole study period. Cladoceran populations exhibited non-synchronous peaks of abundance, evidencing different ecological optima. Temperature seemed to be the main structuring factor of this assemblage. The way biotic interactions influenced pelagic cladoceran assemblage in this reservoir was not clear and needs further research.

The results of 32 seasonal sampling sessions in 2000 were used to assess the dynamics of autotrophic picoplankton (APP), with special reference to the cyanobacterial component in Strzeszynskie Lake, a eutrophic lake in mid-western Poland. The abundance of picocyanobacteria (Pcy) fluctuated from 1.2x104 to 8.1x105cells mL-1 and the average abundance and biomass were 2.0x105cells mL-1 and 0.094 mg L-1, respectively. Pcy development was characterised by maxima in spring and summer. The summer maximum was twice the spring Pcy numbers. Eukaryotic APP (E-APP) were also present but in low numbers and their annual average contribution to the total APP community was only about 0.3% in abundance and about 3% in biomass. The spring Pcy community was dominated by single-celled cyanobacteria (S-Pcy) and in summer by colonial forms (C-Pcy). Throughout the sampling period, C-Pcy constituted on average 55% of the total Pcy and up to 90% in summer. C-Pcy abundance was significantly and positively correlated with water temperature (r=0.40, p=0.023, n=32). S-Pcy exhibited a distinct seasonal variation in FDC, ranging from 10% to 35%. Most FDC values above 30% were recorded from late May to mid July.

Phyllognathopus bassoti Rouch, 1972, originally described from Long Island, Papua New Guinea, and later reported from the Philippines, is found for the first time in India. This subterranean species is redescribed and its ecology and zoogeography are discussed. Also, the systematics of the family Phyllognathopodidae is discussed and a key to genera and species is given. As a result of the taxonomic analysis, three species are here synonymized: Phyllognathopus insularis Chappuis, 1940 and P. camptoides Bozic, 1965 with P. chappuisi Delachaux, 1924; and P. volcanicus Barclay, 1969 with P. viguieri (Maupas, 1892). It has been observed that odonate nymphs prey on adults and copepodids of P. bassoti, an interaction not known until now.

A new species of Enchytraeidae, Cernosvitoviella tridentina sp.n., is described from alpine streams (Stelvio National Park, Trentino). C. tridentina sp.n. belongs to a group of species with spermathecae confined to the V segment; it particularly resembles Cernosvitoviella carpatica (Cernosvitov), C. minor Dozsa-Farkas and C. celere Nurminen, but differs from these species by some important anatomical features: the presence of small seminal vesicles, longer ectal ducts of the spermathecae and (from two first species) by deep incision of the posterior margin of the brain.

While the impacts of groundwater contamination on interstitial invertebrate communities are well studied, very few work have examined other potential disturbance resulting from agricultural practices. In the present study, the interstitial crustacean fauna was studied in an alluvial aquifer characterized by intensive cereal irrigation, to test the influence of groundwater extraction on the assemblage characteristics (abundance, diversity, persistence, species distribution patterns). Micro- and macrocrustaceans were sampled at 4 seasons in 15 wells with contrasted groundwater use (cereal irrigation / domestic use / no groundwater use) scattered over a 250 km2 alluvial floodplain. The aquifer harbored diverse assemblages dominated numerically and specifically by cyclopoids. Total abundance, diversity expressed using species richness or Shannon index, overall persistence in species composition did not vary between stations whether micro- or macrocrustaceans were considered. Yet, marked differences in the cyclopoids assemblages composition were found in relation to groundwater utilization. Disturbed irrigation wells were dominated by epigean species, while hypogean species were mainly found in less impacted domestic wells. In contrast, amphipods/isopods did not exhibit particular assemblages composition between irrigation, domestic or abandoned wells. The differential responses between micro- / macrocrustaceans, epigean / hypogean species emphasized that levels of disturbance are strongly taxondependent. At the scale of the aquifer, these results suggest that groundwater extraction resulting from intensive irrigation has to be considered as a potential disturbance for the interstitial communities.

Thirty-six chrysophycean stomatocysts are reported from the dystrophic Staw Toporowy Nizni lake in the Tatra National Park, Poland. Of these, 7 morphotypes are new to science, 10 are new to Europe, and 13 are new to Poland. SEM micrographs and data on distribution are provided for each stomatocyst. Synonimizations of two stomatocysts are proposed: stomatocyst 58 Hansen 2001 with stomatocyst 117 Zeeb et al. 1990, and stomatocyst 91 Hansen 2001 with stomatocyst 239 Duff et al. 1995. The number of chrysophycean stomatocysts recorded from Poland is currently estimated to comprise 65 extant morphotypes.