An overview of Cladoceran studies conducted in mine water impacted lakes

Peer reviewe

An overview of Cladoceran studies conducted in mine water impacted lakes

Peer reviewe

NiSO4 spill inflicts varying mortality between four freshwater mussel species (including protected Unio crassus Philipsson, 1788) in a western Finnish river

Peer reviewe

Paleolimnological Fingerprinting of the Impact of Acid Mine Drainage After 50 Years of Chronic Pollution in a Southern Finnish Lake

Acid mine drainage (AMD) is acknowledged to have long-lasting impacts on aquatic environments. Hence, mines have also been detected to pose problems years after closure due to the leaching of toxic drainage initiated by sulfide oxidation. To assess the effects of chronic but relatively low volume acid mine drainage derived from the Haveri copper-gold mine operating between 1938 and 1960 on a freshwater bay in southern Finland, we compared cladoceran assemblages from the pre-mining period with contemporary populations using paleolimnological approaches and multiple sediment cores. The cladoceran community of the pre-mining era differed significantly from the contemporary community of the lake (ANOSIM R = 0.91; p = 0.0001), but closely resembled the contemporary community of a nearby non-polluted reference site. Our results suggest that the differences in species compositions between pre-mining and contemporary samples are most likely caused by eutrophication and not by the AMD impact. Because AMD at our study site is most intense during the spring snowmelt period, cladocerans may avoid seasonal pollution peaks through winter dormancy. Possible pollution peaks resulting from heavy rains during the summer may have negative impacts on the cladoceran community, but such short-term impacts are probably rapidly counteracted by immigration from cleaner areas of the lake.Peer reviewe

Spatio-temporal impact of salinated mine water on Lake Jormasjärvi, Finland

The salinization of freshwater environments is a global concern, and one of the largest sources of salinated water is the mining industry. An increasing number of modern mines are working with low grade sulfide ores, resulting in increased volumes of potentially harmful saline drainage. We used water monitoring data, together with data on sedimentary fossil remains (cladoceran, diatom and chironomid), to analyze the spatio-temporal (5 sampling locations and 3 sediment depths) impact of salinated mine water originating from the Talvivaara/Terrafame open cast mine on multiple components of the aquatic ecosystem of Lake Jormasjärvi, Finland. Lake Jormasjärvi is the fourth and largest lake in a chain of lakes along the path of the mine water. Despite the location and large water volume, the mine water has changed the chemistry of Lake Jormasjärvi, reflected in increased electrical conductivity values since 2010. The ecological impact is significant around the inflow region of the lake, as all biological indicator groups show a rapid and directional shift towards new species composition. There is a clear trend in improved water quality as one moves further from the point of inflow, and as one looks back in time. Our results show that salinated mine water may induce rapid and large scale changes, even far downstream along a chain of several sinking basins. This is of special importance in cases where large amounts of waste water are processed in the vicinity of protected habitats.Peer reviewe

Waste water discharge from a large Ni-Zn open cast mine degrades benthic integrity of Lake Nuasjärvi (Finland)

The Talvivaara/Terrafame multi-metal mining company is Europe’s largest nickel open cast mine, it is also known for the largest wastewater leakage in the Finnish mining history and a series of other accidents. In this paleolimnological study, influences of a recently constructed treated waste water discharge pipeline into Lake Nuasjärvi were investigated by analyzing past (pre-disturbance) and present community compositions of key aquatic organism groups, including diatoms, Cladocera and Chironomidae, along spatial (distance, water depth) gradients. In addition to defining ecological changes and impacts of saline mine waters in the lake, chironomids were used to quantitatively reconstruct bottom water oxygen conditions before and after the pipe installation (in 2015). The diatom and cladoceran communities, which reflect more the open-water habitat, showed only relatively minor changes throughout the lake, but a general decrease in diversity was observed within both groups. Chironomids, which live on substrates, showed more significant changes, including complete faunal turnovers and deteriorated benthic quality, especially at the sites close to the pipe outlet, where also chironomid diversity was almost completely lost. Furthermore, the reconstructed hypolimnetic oxygen values indicated a major oxygen decline and even anoxia at the sites near the pipe outlet. The limnoecological influence of the pipe decreased at sites located counter-flow or behind underwater barriers suggesting that the waste waters currently have location-specific impacts. Our study clearly demonstrates that whereas the upper water layers appear to have generally maintained their previous state, the deep-water layers close to the pipe outlet have lost their ecological integrity. Furthermore, the current hypolimnetic anoxia close to the pipe indicates enhanced lake stratification caused by the salinated mine waters. This study clearly exhibits the need to investigate different water bodies at several trophic levels in a spatiotemporal context to be able to reliably assess limnoecological impacts of mining.Peer reviewe

The analysis of freshwater pearl mussel shells using µ-XRF (Micro X-Ray Fluorescence) and the applicability for environmental reconstruction

Peer reviewe

Climate and productivity affect total mercury concentration and bioaccumulation rate of fish along a spatial gradient of subarctic lakes

Climate change is resulting in increased temperatures and precipitation in subarctic regions of Europe. These changes are extending tree lines to higher altitudes and latitudes, and enhancing tree growth enabling intensification of forestry into previously inhospitable subarctic regions. The combined effects of climate change and land-use intensification extend the warm, open-water season in subarctic lakes and increase lake productivity and may also increase leaching andmethylation activity of mercury within the lakes. To assess the joint effects of climate and productivity on total mercury (THg) bioaccumulation in fish, we conducted a space-for-time substitution study in 18 tributary lakes of a subarcticwatercourse forming a gradient fromcold pristine oligotrophic lakes in the northern headwaters to warmer and increasingly human-altered mesotrophic and eutrophic systems in the southern lower reaches. Increasing temperature, precipitation, and lake productivity were predicted to elevate length-and age-adjusted THg concentrations, as well as THg bioaccumulation rate (the rate of THg bioaccumulation relative to length or age) in muscle tissue of European whitefish (Coregonus lavaretus), vendace (Coregonus albula), perch (Perca fluviatilis), pike (Esox lucius), roach (Rutilus rutilus) and ruffe (Gymnocephalus cernua). A significant positive relationship was observed between age-adjusted THg concentration and lake climateproductivity in vendace (r(2) = 0.50), perch (r(2) = 0.51), pike (r(2) = 0.55) and roach (r(2) = 0.61). Higher climate-productivity values of the lakes also had a positive linear (pike; r(2) = 0.40 and whitefish; r(2)= 0.72) or u-shaped (perch; r(2) = 0.64 and ruffe; r(2) = 0.50) relationship with THg bioaccumulation rate. Our findings of increased adjusted THg concentrations in planktivores and piscivores reveal adverse effects of warming climate and increasing productivity on these subarctic fishes, whereas less distinct trends in THg bioaccumulation rate suggest more complex underlying processes. Joint environmental stressors such as climate and productivity should be considered in ongoing and future monitoring of mercury concentrations. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

Human impacts on the cladoceran community of Jili Lake, arid NW China, over the past century

Deterioration of aquatic ecosystems, as a consequence of human-induced disturbances, is a critical global concern. To fully understand the responses of aquatic systems to anthropogenic impacts, it is crucial to assess long-term changes in lakes. The water quality of Jili Lake, a large water body in northwest China, has deteriorated recently, owing to the growing impacts of regional warming and human activities. Thus, Jili Lake was a prime candidate for evaluation of historical multi-stressor impacts. Meteorological data, historical documents, and assemblages of cladoceran microfossils in the sediments of Jili Lake were employed to investigate changes in the cladoceran community over the past century, and to evaluate the response of that aquatic community to human activities. From the 1920s to the 1950s, species richness of the cladoceran community was high, which reflected conditions of relatively low human impact. From the 1960s to 1970s, a sharp decrease in Bosmina longirostris, a planktonic cladoceran species, suggested a decrease in water level as a result of dam construction and intensified water exploitation. Since the 1980s, the water level in the lake has been restored, but increased fish farming and construction of a water storage facility caused salinisation and eutrophication of Jili Lake. Accordingly, the cladoceran community displayed distinct signs of a regime shift, with a gradual transition to dominance of B. longirostris and a sharp decrease in littoral species (e.g. Leydigia leydigi, L. acanthocercoides, Alona quadrangularis, Alona affinis). Our results suggest that human-induced disturbances were the main factor that drove changes in the cladoceran community since about the mid-20th century.Peer reviewe

Pitkän aikavälin politiikalla läpi murroksen – tahtotiloja työn tulevaisuudesta

Olemme keskellä suurta työn murrosta. Työn tulevaisuuteen liittyviä haasteita on helppoa nimetä, mutta työn muutoksen kaltaiset monimutkaiset pitkäaikaiset muutosilmiöt eivät helposti käänny politiikkatoimiksi ja konkreettisiksi ratkaisuiksi. Muutosta on silti mahdollista ohjata yhteisesti tunnistettujen pitkän aikavälin tahtotilojen avulla. Tämän tutkimuksen tavoitteena on ollut tunnistaa työhön liittyviä toivottavia tulevaisuuksia, päätöksentekotarpeita sekä yhteiskunnallisia ratkaisuja asiantuntijahaastatteluihin ja kansallisen tason kyselytutkimukseen perustuen. Lisäksi raportissa ehdotetaan toimintamallia, jolla pitkän aikavälin keskustelua työn tulevaisuudesta voidaan käydä myös jatkossa. Raportti pohjautuu käsiteltyjen viiden teeman osalta Tulevaisuusselonteon 1. osaan (VNK 2017). Tutkimuksesta vastasi ajatushautomo Demos Helsinki yhteistyössä Teknologian tutkimuskeskus VTT:n kanssa. Tutkimuksesta keskeiset havainnot ovat seuraavat: Työn tekemisen muodot ja työsuhteet moninaistuvat, mikä edellyttää muutoksia esimerkiksi lainsäädännössä ja sosiaaliturvassa. Työn aika- ja paikkasidonnaisuus heikkenee, mutta muutos ei ole yhtä voimakas tai samantahtinen kaikilla aloilla. Koulutuksessa korostuu jatkuva oppiminen: Tarvitsemme Suomeen koko väestön kattavan, laadukkaan elinikäisen oppimisen järjestelmän. Toimeentulo muuttuu niin, että työmarkkinoiden ja koko työelämän joustavuus lisääntyy. Päätöksentekijöiden on tärkeää ymmärtää työn useita erilaisia ja muuttuvia välinearvoja taloudellisten arvojen lisäksi, jotta emme edistä keskenään ristiriitaisia tavoitteit