1,721,148 research outputs found
A 40-year perspective of an alpine lake: is everything the same?
No full textMountain lakes are the most affected by climate change; however, few of these lakes are regularly sampled because of their remoteness. We discussed limnological data (e.g. water temperature, light transparency, and plankton diversity) of Lake Campo (1944 m above sea level, Adamello Mountains, Italy) scattered over almost forty years in the light of climate change. Specifically, occasional samplings in 1980, 1988, 2016, 2017, and 2018 and more extensive surveys in 1997 and 2015 were carried out. Among the investigated years, 2015 was the warmest. Inter-year variability in water temperature was quite marked in Lake Campo. Water temperature profiles of July (1980, 1997, 2015) showed increased surface warming, while the deeper layers (> 15 m) were always isothermal at around 5 ◦C. Hypolimnetic dissolved oxygen never decreased below 50 % saturation. Secchi disk depth was not substantially different among years. Summer profiles of light transparency showed discontinuous light attenuation, which was tentatively attributed to algae located in deeper layers. In cluster analysis of phytoplankton and zooplankton data, differences between seasons but not years were found. The autumn decline of Bacillariophyta and the increase of mixotrophic Cryptophyta was linked to decreasing silica concentrations towards autumn. Apart from this general pattern, several observations (e.g. high abundance of Tovellia sanguinea, requiring warmer temperatures and thermal stratification to compete with Bacillariophyta; a spatially extended metalimnetic oxygen maximum in July 2015) showed the effects of particularly warm conditions of 2015 compared to 1997. The continuous presence of crustacean males and first generation of rotifers (Polyarthra f. aptera) hatching from sexual eggs indicated the importance of sexual reproduction in the lake. Length measurements of Daphnia gr. longispina before (1997) and after (2015) non-native fish removal and Arctic char introduction were similar and indicated no apparent change in predation pressure. Studies like this, despite scattered data, can provide valuable insights into the changes mountain lakes undergo through tim
The zooplankton population of a small alpine lake: Lake Malghette (Trentino, Italy)
No full textThe zooplankton population of Lake Malghette (1891 m asl) was surveyed in 1994-1995. The zooplankton of this small oligotrophic lake included the copepods Cyclops abyssorum-tatricus, Acnathodiaptomus denticornus, the cladocerans Holopedium gibberum, Daphnia gr longispina, and the rotifer Kellikottia longispina
Taxonomic and functional diversity of rotifers, what do they tell us about community assembly?
No full textCommunity assembly depends on dispersal, environmental parameters, and species interactions. Here, we compared rotifer communities from two environmentally distinct, but connected basins of Lake Tovel for five years, with biweekly (2002) and monthly (2003-2006) sampling. We applied taxonomic and functional diversity-based multivariate analyses (principal components analysis, redundancy analysis) to compare rotifer communities in both basins. For functional diversity, we focused separately on defence and feeding traits that were inferred from rotifer morphology. Taxonomic and functional diversity were generally higher in the deep compared to the shallow basin. In multivariate analyses, water residence time and surface water temperature were important environmental predictors for both taxonomic and functional diversity while the importance of competitors and predators varied according to defence or feeding traits used. The difference between basins showed a gradient from taxonomic (marked difference) to functional diversity, indicating that the processes that regulate feeding traits were similar in both basins while those regulating defence traits were different. The distinction of different aspects of rotifer life (i.e. feeding and predation) outlined different important drivers that would have been neglected by focusing solely on species abundance. Furthermore, we outlined the status quo of trait research in rotifer ecology including its challenges and difficulties
Valori eritrocitari per alcuni pesci dei laghi trentini
No full textComparison of erythrocyte concentrations in different species of freshwater fis
Indagine biologica preliminare delle acque correnti nel Trentino: problemi nell'applicazione dell'indice di qualità.
No full textRemembering Alvise Vittori (Riva del Garda 1932 – Trento 2018)
Full text linkObituary for Alvise Vittori (Riva del Garda 1932 - Trento 2018), a well-known Italian ichthyologist, limnologist and all-round ecologist. After many years of service as an aquatic biologist, he was appointed Director of the Experiment Station, where he oversaw its transition to the now Fondazione Edmund Mach. His professional interests ranged from fisheries to lake and stream monitoring to habitat restoration. Alvise was instrumental in starting lake monitoring in Trentino (1973) and in the 1980s founded the San Nicolò Laboratory on Lake Garda. He was involved in lake restoration projects, most notably Lake Caldonazzo, initiated the ecological mapping of Trentino’s waterways using macroinvertebrates and developed the first Fisheries Management Plan (Carta Ittica -1983) in Italy
Indagine biologica preliminare delle acque correnti nel Trentino: impatto delle vasche Imhoff
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