Angela Boggero

Factors affecting water chemistry of alpine lakes

During a four-year study (1988–1991), 413 lakes in the Central Alps (Italy, Switzerland and Austria) were investigated to quantify their acidification. The ionic content of the lakes was generally low: 68% of them had alkalinity values of less than 200 µeq 1−1 and were regarded as sensitive to acidification. Moreover, 36% of the lakes showed alkalinity values of less than 50 µeq 1−1. Redundancy Analysis was used to relate the hydrochemistry of 187 lakes to their catchment characteristics. Calcite weathering was the main factor influencing lake chemistry. The same analysis, applied to a subset of 101 lakes lying in watersheds exclusively composed of silicic rocks, showed that lake chemistry was influenced by silicate weathering and nitrogen uptake. These processes were found to be mainly related to lake altitude and the fraction of the watershed not covered by vegetation, i.e. controlled by temperature. The importance of these relations to explain the pH shift produced by climatic variation is also discussed.

Distribution of benthic invertebrates in relation to environmental factors. A study of European remote alpine lake ecosystems

Alpine lake ecosystems are, despite their remoteness, vulnerable to long-range transported air pollutants due to their normally low capacity to neurralize acidic deposition. The soi! and vegetation cover in their catchments are thin and pollutants are not effectively prevented from reaching rhe surface waters. Further, high mountain ecosystems are very sensitive to climate change as temperature limits for many species and processes are exceeded. Pollutants accumulate more easily in cold, low-alkaline waters and future climatic warming in Europe is predicted to be greatest in the arctic and alpine regions (WATHNE et al. 1997). With this background a multi-national project, AL:PE (Acidification of mountain Lakes: Palaeolimnology and Ecology), funded by the European Commission, was started in 1991. lt represents the first comprehensive study of remote lakes at a European scale. The sensitivity of invertebrate species to airborne acid pollution is frequendy used as a too! in monitoring freshwater ecosystems (RADDUM et al. 1988, FJELLHEIM & RADDUM 1990, HAMALAINEN & HUTTUNEN 1990). Invertebrates are also a valuable group in detecting changes in the nutrient levels of lakes (S.t:THER 1979, WIEDERHOLM 1984). Such changes may also be connected to early stages of pollution (ScHNELL & RADDUM 1993). The main objective of the invertebrate studies of the AL:PE programme was to increase our understanding of high altitude freshwater ecosystems and their response to environmental changes. This paper presents an overview of the results obtained in the AL:PE 2 programme (1993-1995, WATHNE et al. 1997).

Chemistry and critical loads of Alpine lakes in Canton Ticino (Southern Central Alps)

Abstract: We studied the chemistry of atmospheric deposition and of 55 Alpine lakes in Canton Ticino (Switzerland). The chemistry of the precipitation and the deposition of ions from the atmosphere were characterized by a marked gradient, with higher values for sulphate, nitrate, ammonium and acidity in the southernmost part of the Canton, and a halving of the values in the northern area. Results showed that most of the 55 lakes, mainly located in the north, are sensitive to acidification, 87 % and 33 % of them having alkalinity values of below 200 and 20 μeq l-1, respectively. The main processes determining water chemistry were carbonate and silicate weathering depending on the geo-lithology of the watershed, while the input of atmospheric deposition was a source of variability for nitrogen and chloride.¶A comparison between the critical and present loads of acidity to the lakes showed that a reduction of more than 50 % of the acidifying compounds would be required to keep a safe level of alkalinity in all the lakes. Ammonium plays an important role in acidification processes and must be considered in the reduction of emissions.

Macroinvertebrates assemblages of high altitude lakes, inlets and outlets in the southern Alps

The invertebrate fauna of 21 high altitude lakes on the southern side of the Alps (Italy and Switzerland) were sampled once in the 1990 s. A total of 193 taxa was identified in 48 samples: 66 taxa were exclusive to the littoral zone, 17 to the outlets and 23 to the inlets. Chironomids prevailed in all environments with few exceptions. Inlets and littoral zones proved to be the richest habitats in number of taxa, while the littoral zones were richest in number of individuals. In all, 17,778 individuals were found in the Pennine-Lepontine Alps and 1966 in the Rhaetian ones. The number of taxa was 108 and 122, respectively. 69 taxa were exclusive to the former and 83 to the latter. Four groups of lakes have been distinguished by DCCA analysis applied to the littoral chironomid community. Water temperature, altitude, hydrochemistry, and lake area were the abiotic variables mostly related to chironomid distribution. Many steno-thermal species, typical of oligotrophic waters and high mountain streams were found, such as Zavrelimyia punctatissima, Diamesa latitarsis gr., Orthocladius frigidus, Prosimulium latimucro, Dictyogenus fontium, Baetis alpinus and Crenobia alpina. Only a few taxa such as D. fontium, Halesus radiatus, Plectrocnemia conspersa, Heterotris-socladius marcidus, Ablabesmyia sp., and Procladius sp. appeared to be tolerant to acidic conditions. These findings, as well as the rarity of molluscs, indicated that these environments are slightly acidic or at risk of acidification. Further studies on macroinvertebrates are required if they are to be used as possible indicators of local and global changes (e.g. acid deposition) in remote regions.

Freshwater Oligochaeta in two mountain ranges in Europe: the Tatra Mountains (Poland) and the Alps (Italy)

The oligochaete fauna of littoral zones, infl ows and outfl ows of 11 lakes in the Polish Tatra Mountains and 10 lakes in the Italian Alps were compared. The study lakes were located in the alpine zone, they varied in size and depth, and were found prevalently on acidic crystalline bedrock containing a small percentage of calcare- ous rocks. On average, Oligochaeta represented from 10 to 17 % of the total benthic fauna. Enchytraeidae had the highest number of species (7 per group of lakes), while Naididae were next with 3 species. Common Enchytraeidae genera were: Cognettia, represented by the same species in both mountain ranges, and Cernosvitoviella, with 1 species in the Polish lakes (Cernosvitoviella tatrensis) and 3 species in the Italian lakes (Cernosvitoviella ampullax, C. atrata and C. microtheca). In the Naididae, the genus Nais was represented by 3 species in the two lake groups, but only 2 species with high percentages (Nais variabilis in the Tatras and Nais communis in the Alps). Although Naididae are more likely to be found in freshwater with more favourable environmental conditions, no correlation existed between pH or alkalinity and their geographical distribution. The results of a two-year study on Lake Czarny pod Rysami (Tatras) are also presented, highlighting the lower number of species collected in the present campaign than in the previous one, due to different sampling methods.

A geographic distribution data set of biodiversity in Italian freshwaters

We present a data set on the biodiversity of Italian freshwaters, including lakeshores and riverbanks of natural (N=379: springs, streams and lakes) and artificial (N=11: fountains) sites. The data set belongs partly to the Italian Long Term Ecological Research network (LTER-Italy) and partly to LifeWatch, the European e-Science infrastructure for biodiversity and ecosystem research. The data included cover a time period corresponding to the last fifty years (1962-2014). They span a large number of taxa from prokaryotes and unicellular eukaryotes to vertebrates and plants, including taxa linked to the aquatic habitat in at least part of their life cycles (like immature stages of insects, amphibians, birds and vascular plants). The data set consists of 6463 occurrence data and distribution records for 1738 species. The complete data set is available in csv file format via the LifeWatch Service Centre.

A thesaurus for phytoplankton trait-based approaches: Development and applicability

Abstract In the last few decades, functional trait-based approaches have undergone an extraordinary expansion in phytoplankton ecology, due to the relative simplicity and the well-defined traits that determine the ecological niche of these organisms. A large quantity of heterogeneous and distributed data has been produced on phytoplankton traits and their use could be made more effective and efficient if data harmonization and interoperability would be improved. The use of controlled vocabularies and thesauri is an acknowledged good practice to establish the foundation for semantic interoperability, a critical requirement for reuse and sharing of data. In fact, thesauri, collectively constructed, bypass ambiguity issues in natural language, facilitating the identification and integration of the information available in multiple data sources and allowing both scientists and computer applications to interpret more effectively the meaning of data. Here we present a semantic resource on phytoplankton functional traits: the PhytoTraits thesaurus ( http://thesauri.lifewatchitaly.eu/PhytoTraits/index.php ). PhytoTraits is the result of the interdisciplinary collaboration of experts both from the phytoplankton functional domain and from information and communication technologies, working together within LifeWatch Italy, the Italian node of the e-science European infrastructure for biodiversity and ecosystem research. PhytoTraits is the first initiative to deal with the semantics of phytoplankton functional traits, focusing on morpho-functional traits towards standardized bio-volume assessment. It reflects the agreement of a scientific expert community to fix semantic properties (e.g. label, definition) of approximately 120 traits. Following semantic web standard technologies, the thesaurus was implemented in Simple Knowledge Organization System (SKOS), a common data model based on the Resource Description Framework (RDF). PhytoTraits is freely available online, it can be queried through a SPARQL endpoint ( http://thesauri.lifewatchitaly.eu/PhytoTraits/sparql.php ) and is also accessible via API ( http://thesauri.lifewatchitaly.eu/PhytoTraits/services.php ) for integration with other systems. If adopted as a standard and rigorously applied and enriched by the scientific community, PhytoTraits, providing harmonized concepts with associated unique and resolvable URIs, has the potential to significantly reduce the barriers to data discovery, integration, and exchange.

An historical and geographic data set on the distribution of macroinvertebrates in Italian mountain lakes

Author(s): Boggero, Angela; Garzoli, Laura; Varini, Gianfranco | Abstract: Macroinvertebrates play a key role in freshwater food webs, acting as major links between organic matter resources, primary consumers (such as bacteria), and secondary consumers (e.g.fish, amphibians, birds, and reptiles). In this paper we present a data set encompassing all geographic and historical data available on macroinvertebrates of the Italian mountain lakes from 1902 to 2016. The data set, divided per Italian mountain range (Alps and Apennines) and administrative region, covers more than a century of studies of many foreign and Italian scientists. The data set includes 2372 records and shows macroinvertebrate occurrence data in 176 Alpine and in 13 Apennine lakes, of which 178 of natural origin, 5 reservoirs, and 6 artificially extended. The data set lists 605 taxa, updated on the basis of their current taxonomic position. Only 353 taxa are identified at species level, highlighting the still poorly investigated biodiversity of Italian mountain lake macroinvertebrates. Since they function as key elements to characterize lake ecological status, our data set emphasizes the huge taxonomic effort that still has to be undertaken to fully characterize these ecosystems. The data set is available in csv (comma-separated values) format.

Oligochaete assemblages of Swiss Alpine lakes

Abstract The present paper describes the oligochaete assemblages of 12 Swiss Alpine lakes (1700–2500 m above sea level) in Canton Ticino. The lake catchment geology is dominated by gneiss. The scarcity of carbonate rocks leads to a low buffering capacity, increasing the lakes’ sensitivity to acidification. Because of their very low phosphorus concentrations, they are defined as ultraoligotrophic. Oligochaetes were identified from kick-samples taken from the outflow and littoral zone of the lakes one to three times per year in 1991–1994, 2003 and 2007, when the lake water chemistry was also characterized. Oligochaete assemblages consisted of 19 species in total, 18 of which were found in the littoral zone, and 10 in the outlets. Amongst them, Cernosvitoviella goodhui Healy, 1975 was recorded in Switzerland for the first time. Principal component analysis (PCA), performed excluding the highly alkaline Lake Bianco (pH = 7.8 and alkalinity = 566 µeq L−1) due to its atypical chemical composition, divided the remaining lakes into two groups with different sensitivity to acidity: the first group of four lakes was characterized by a higher average pH (6.4) and alkalinity (32 µeq L−1), whilst the second group of seven lakes was characterized by a lower average pH (5.7) and alkalinity (5 µeq L−1). Multivariate analysis performed on data collated from the littoral zone highlighted geo-lithology as a key driver in determining the species distribution among lakes. When applied to the lake outlet data, a similar distinction between acidic and calcareous waters was implied. Precipitation influenced the oligochaete assemblage in the littoral zone. During years with higher annual rainfall, the relative abundance of Enchytraeidae increased, probably because their semi-aquatic nature allows them to colonize the littoral zones that dry out periodically.