First record of Parochlus kiefferi (Garrett, 1925) in a sediment sequence from a Slovak mountain lake with notes on paleolimnological interpretation

Subfossil larval remains of a rare Podonominae, Parochlus kiefferi (Garrett, 1925), were identified in a sediment sequence from a mountain lake in the Low Tatra Mountains, Slovakia, and represent the first record of the species for Slovakia. The depth at which the P. kiefferi remains were found, along with the taxonomic composition of the corresponding chironomid assemblage dominated by cold-stenothermal taxa, indicate that the sample can be dated back to the Little Ice Age. Additionally, notes on the chironomid remains which appear in the sediment sample are provided here and can offer further insight into paleolimnological interpretation

Diversity and composition of macroinvertebrate assemblages in high-altitude Tibetan streams

Knowledge on the ecology of streams at extreme altitudes is relatively sparse. We conducted a preliminary survey of the macroinvertebrate fauna of Tibetan streams in June 2009 and August 2011 and compared streams with different water sources. We collected quantitative samples of macroinvertebrates and measured physicochemical variables at 16 sites (8 each sampling year) at altitudes ranging from 4315 to 5065 m a.s.l. and grouped the sites into 3 types according to origin: glacier-fed, rain-fed, and lake-outlets. We identified 38 taxa, with a mean of 8.9 taxa per site. Overall the benthic fauna was dominated by insects (71%), mainly Diptera (especially Chironomidae). Ephemeroptera, Plecoptera, and Trichoptera were found at nearly all sites but mostly in low numbers; however, the fauna was significantly different in the 2 sampling years, especially due to the proportions of Chironomidae (68% in June 2009 and 10% in August 2011) and Baetidae (6% vs. 35%, respectively). The 3 stream types had significantly different faunas. Rain-fed streams had the highest total taxon richness (γ-diversity), but glacier-fed streams had a slightly higher taxon turnover rate (β-diversity). Percent glacial cover in the catchment and water turbidity explained most of the variability in taxon richness. Although not particularly taxon rich compared to other high-altitude streams, the Tibetan stream fauna showed considerable spatial variability. The fast retreat of the glaciers and permanent snow fields in Tibet makes further studies on distribution patterns and driving forces for aquatic biodiversity urgent

The Arctic in the twenty-first century: changing biogeochemical linkages across a paraglacial landscape of Greenland

The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco- and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm

Chironomids (Insecta, Diptera, Chironomidae) from alpine lakes in the Eastern Carpathians with comments on newly-recorded species from Ukraine

Chironomids (Insecta, Diptera, Chironomidae) from alpine lakes in the Eastern Carpathians with comments on newly-recorded species from Ukrain

The sediments of Lake Logurinn - A unique proxy record of Holocene glacial meltwater variability in eastern Iceland

The full Holocene development of the large (8100 km(2)) Vatnajokull ice cap in Iceland with its many outlet glaciers is poorly known. The idea of an early deglaciation, leading to a glacier-free period in mid-Holocene, followed by the Neoglaciation is still the main concept for the glacial history in the North Atlantic region, including Iceland. We have examined a continuous sediment record from the glacier-fed Lake Logurinn in eastern Iceland to infer Holocene meltwater variability of Eyjabakkajokull, which is a surge-type outlet glacier of the Vatnajokull ice cap. We focus on the early and mid-Holocene, and our data show that Eyjabakkajokull receded rapidly during the final phase of the last deglaciation, and did not deliver glacial meltwater to Lake Logurinn by 9000 years BP, suggesting that Eyjabakkajokull was significantly smaller than today at that time. The return of glacial meltwater transport to Lake Logurinn, and thus a return of Eyjabakkajokull is dated to ca 4400 years BP, suggesting an almost 5000 years long glacier-free period during early and mid-Holocene. During this time period, we infer that the 8.2 ka cold event did not cause a significant expansion of Eyjabakkajokull, however, we note a marked decrease in the aquatic productivity in Lake Logurinn, which is suggested to be the result of shorter ice-free seasons of Lake Logurinn. The Holocene Thermal Maximum is inferred by a period of maximum Holocene aquatic productivity, and dated to ca 7900-7000 years BP. Following the re-formation of Eyjabakkajokull ca 4400 years BP, we suggest that the glacier reached stable conditions ca 1700 years BP, and remained fairly stable until the later part of the Little Ice Age, when Eyjabakkajokull reached its maximum Holocene extent. (C) 2012 Elsevier Ltd. All rights reserved