Soil algae from northern Victoria Land (Antarctica)

Samples of dry mineral soil with no apparent algal vegetation were collected from 20 locations of northern Victoria Land (Antarctica) to determine their microalgal content. Direct microscopic examination and cultures revealed the presence of 63 taxa, mostly represented by Chlorophyta (29 taxa) and Cyanobacteria (22 taxa). Other components observed included Xanthophyta (9 taxa) and Bacillariophyta (3 taxa). Descriptions of the 15 species newly recorded for Continental Antarctica or the whole of Antarctica are given. A comparison among other studies shows that northern Victoria Land edaphic microflora only partially corresponds with the microflora present in other locations of Victoria Land or in other areas of Antarctica

Trophic condition of the volcanic Lake Nemi (Central Italy): environmental factors and planktonic communities in a changing environment

Lake Nemi is an interesting case of anthropogenic overexploitation which has caused its progressive environmental deterioration in the past decades. On this lake historical data about the trophic situation are available from 1975 to 1984. The research performed in 2002-03, about ten years after the diversion of urban waste waters, concerned a biological investigation on the phyto- and zooplanktonic communities, integrated with a physico-chemical analysis. The aims of our study are to evaluate the current water quality of the lake and compare it with the water quality observed in 1982-1983, when all biotic and abiotic components indicated a heavily compromised hypereutrophic condition. The water quality data and the comparison with a previous study point out that the biological aspects have partially changed (increased number of Cyanobacteria and phytoplanktonic taxa, particularly Clorophyta and Dinophyta; zooplankton composition changed at a species level, with the appearance of taxa associated to light trophic conditions), and the physico-chemical conditions significantly improved. The mean transparency, dissolved oxygen, nutrients and chlorophyll-a concentrations have all improved. Mean annual temperature at different depths increased, probably due to differences in climatic period and the lowering of the lake surface level (from 32.5 to 27.5 m in 1982 and 2002, respectively). Our results indicate a general improving trend in water quality is taking place since the diversion of waste water discharges. The present abiotic characteristics of the lake allow the phytoplankton to distribute itself in the whole epilimnion, and the zooplankton in the whole water column. A possible further improvement is hypothesized, and the constraints represented by excessive water level lowering and water temperature increasing are also discussed

Navicula skuae sp nov., a freshwater diatom from Continental Antarctica

The freshwater diatom Navicula skuae sp. nov. is described from benthic and floating algal mats of some lakes in northern Victoria Land (Antarctica). The detailed morphology of this species is examined using scanning electron microscopy (SEM). Navicula skuae is compared with other similar species

Floristic studies on freshwater algae of Lake Gondwana, Northern Victoria Land (Antarctica)

Benthic algal mats and phytoplankton of Lake Gondwana (Northern Victoria Land, Antarctica) were investigated. Biomass, chlorophyll content and floristic analyses were carried out on algal mats. The mars are composed of two layers different in colour, floristic composition and chlorophyll content. The algal flora of the mats amount to 34 taxa (19 Cyanophyta, 7 Bacillariophyta, 8 Chlorophyta). The phytoplankton community is species-poor (only 5 taxa). Cryptophyta account for about 98% of total algal density

Benthic algal mats of some lakes of Inexpressible Island (northern Victoria Land, Antarctica)

Benthic algal mats from four lakes located on Inexpressible Island (northern Victoria Land, Antarctica) were studied, analysing their structure and Aoristic composition. Thirty taxa of algae were identified: 11 Cyanophyta, 15 Bacillariophyta and 4 Chlorophyta. The lake mats contained from 15 (lake C) to 26 species (lake D). The number of diatom frustules in the mats varied from 771 x 10(3) (lake C) to 9428 x 10(3) frustules g(-1) (lake B). In terms of floristic composition and macromorphology, these mats were observed to be very similar to moat mats described from Lake Gondwana (northern Victoria Land) and the Dry Valleys lakes of southern Victoria Land

RiSCC Manual Version 2.0

Regional Sensitivity to Climate Change in Antarctic Terrestrial and Limnetic Ecosystems (RiSCC) is an international research program on Antarctic terrestrial and limnetic organisms and ecosystems. It is sponsored by the Scientific Committee on Antarctic Research (SCAR), a committee of the International Council of Science (ICSU). The RiSCC programme was formally adopted as a research programme under the auspices of the SCAR Working Group on Biology during SCAR XXVI, in Tokyo, Japan, July 2000. A recommendation to approve of this programme was made to the Delegates Meeting of SCAR XXVI. The Delegates agreed to this recommendation. In this manual the agreed methods are being described, which are to be used in RiSCC projects. Methods presented here have been tried in polar regions under extreme conditions, or with organisms obtained from high latitudes, and have been considered appropriate, providing reliable data

Diversity and distribution of Victorian Land biota.

Understanding the relationship between soil biodiversity and ecosystem functioning is critical to predicting and monitoring the effects of ecosystem changes on important soil processes. However, most of Earth's soils are too biologically diverse to identify each species present and determine their functional role in food webs. The soil ecosystems of Victoria Land (VL) Antarctica are functionally and biotically simple, and serve as in situ models for determining the relationship between biodiversity and ecosystem processes. For a few VL taxa (microarthropods, nematodes, algae, mosses and lichens), species diversity has been intensively assessed in highly localized habitats, but little is known of how community assemblages vary across broader spatial scales, or across latitudinal and environmental gradients. The composition of tardigrade, rotifer, protist, fungal and prokaryote communities is emerging. The latter groups are the least studied, but potentially the most diverse. Endemism is highest for microarthropods and nematodes, less so for tardigrades and rotifers, and apparently low for mosses, lichens, protists, fungi and prokaryotes. Much of what is known about VL diversity and distribution occurs in an evolutionary and ecological vacuum; links between taxa and functional role in ecosystems are poorly known and future studies must utilize phylogenetic information to infer patterns of community assembly, speciation, extinction, population processes and biogeography. However, a comprehensive compilation of all the species that participate in soil ecosystem processes, and their distribution across regional and landscape scales is immediately achievable in VL with the resources, tools, and expertise currently available. We suggest that the soil ecosystems of VL should play a major role in exploring the relationship between biodiversity and ecosystem functioning, and in monitoring the effects of environmental change on soil processes in real time and space