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Kubischta, F., Knudsen, K.L., Ojala, A.E.K. and Salonen, V.-P., 2011. Holocene benthic foraminiferal record from a high-arctic fjord, Nordaustlandet, Svalbard. Geografiska Annaler: Series A, Physical Geography, 93, 227-242. DOI: 10.1111/j.1468-0459.2011.00434.x This study presents the results of benthic foraminiferal analyses of a marine core record from about 100 m water depth in the fjord environment of Isvika bay, Nordaustlandet, Svalbard. During the Last Glacial Maximum, the bay was glaciated by the north-western sector of the Svalbard-Barents Sea Ice Sheet. The foraminiferal assemblages reflect glaciomarine conditions during deglaciation and early Holocene (about 11-250-9640 cal. yr bp) followed by glacier-distal environment in an open fjord with relatively high influence of Atlantic waters from the open ocean (9640-7430-cal. yr bp). A subsequent foraminiferal indication of a glacial advance was followed by deposition of a diamicton unit within a short time period at 5800-5700 cal. yr bp. The mid- and late Holocene were characterized by assemblages indicating restricted open-ocean connection and gradually more severe conditions, which are considered to be caused partly by a gradual cooling and freshening of the Atlantic water inflow to the shelf area and partly by a continuous isostatic uplift of the area. The foraminiferal record shows that the environmental changes in Murchisonfjorden are not just an effect of changes in solar insolation but are also influenced by local processes, as well as changes in the Atlantic water inflow to the northern Svalbard shelf and to the fjord via Hinlopenstretet.

A2.5−metrelong marine core from Isvika bay inNordaustlandet (80°N, 18°E) was AMS 14 C dated and analysed for its sedimentological and magnetic parameters. The studied record was found to cover the entire Holocene and indicates major turnovers in the palaeo− hydrography and sedimentary depositional history. The area was deglaciated at around 11,300 BP. The earlyHolocene has indications of rapidmelting of glaciers and frequent deposition of ice−rafted debris (IRD). The climatic optimum terminated with a probable glacier re−advance event occurring ca. 5800 cal BP. This event caused the deposition of a diamicton unit in Isvika bay, followed by a shift towards a colder and amore stratified hydrographic set− ting. The reduction in IRD indicates gradual cooling, which led to the stratification of the bay and eventually to more persistent fast sea−ice conditions by 2500 cal BP. For the last 500 years, Isvika has again been seasonally open.

Mining development sites occasionally host complicated aquifer systems with notable connections to natural surface water (SW) bodies. A low-altitude thermal infrared (TIR) imaging survey was conducted to identify hydraulic connections between aquifers and rivers and to map spatial surface temperature patterns along the subarctic rivers in the proximity of the Hannukainen mining development area, northern Finland. In addition to TIR data, stable isotopic compositions (δ18O, δD) and dissolved silica concentrations were used as tracers to verify the observed groundwater (GW) discharge into the river system. Based on the TIR survey, notable GW discharge into the main river channel and its tributaries (61 km altogether) was observed and over 500 GW discharge sites were located. On the basis of the survey, the longitudinal temperature patterns of the studied rivers were found to be highly variable. Hydrological and hydrogeological information is crucial in planning and siting essential mining operations, such as tailing areas, in order to prevent any undesirable environmental impacts. The observed notable GW discharge was taken into consideration in the planning of the Hannukainen mining development area. The results of this study support the use of TIR imagery in GW–SW interaction and environmental studies in extensive and remote areas with special concerns for water-related issues but lacking the baseline research.

Purpose - The purpose of this paper is to emphasize the importance of groundwater-surface water interaction when studying, modeling and assessing climate change impacts on river water management.Design methodology approach - The investigations were focused on River Vantaa and its tributaries in southern Finland. The main methods used involved aerial infrared photography, thermal profiling of river sediments, water quality measurements, isotopic composition of oxygen and hydrogen δ18O, δ2H and river water temperature measurements. The authors present the first results of the field measurements targeted to identify the groundwater recharge and discharge zones within the river system.Findings - Groundwater discharge zones were found to have a significant impact on water quality and volume in River Vantaa and its tributaries. In the drainage basin, the aerial infrared photography seemed to be a feasible and cost-effective method to identify areas of groundwater discharge across the entire river basin. Around 350 groundwater surface water interaction sites along the 220 km river system could be identified.Practical implications - The interaction sites identified during the season of low flow rate should be considered as potential risk areas because during flood periods groundwater quality might be at risk due to bank infiltration. This should be considered in river basin management within predicted changing climatic conditions.Originality value - This is the first attempt in Finland to map systematically groundwater and river water interactions. The focus of the paper is relevant, because according to the existing climate scenarios, flooding of the main rivers in Finland will be more frequent in future, increasing the probability of groundwater-surface water interaction.

A 28-cm sediment core from an Arctic pond (Nordaustlandet, Svalbard), which is currently subjected to the fertilizing effect of bird guano, was analysed for fossil invertebrates and the physical properties of the sediment. The objective was to examine aquatic community responses to climate warming. Our record reveals that faunal changes have occurred. Initially chironomid assemblages were dominated by a cold-indicating oligotrophic community but this was replaced by a community typical of more nutrient-enriched conditions and warmer water temperature at around AD 1,700–1,800. After AD 1,800, ostracods and Daphnia increase suggesting that a nutrient enrichment threshold was crossed, probably related to increased planktonic algal productivity. In the early twentieth century, organic content markedly increases and magnetic susceptibility values suddenly drop, indicating a further increase in nutrient input and lake productivity. Since the most likely source of nutrients in the lake is goose guano, this suggests that the size of the bird colony may also have increased over this period. These changes coincide with climate warming suggesting a positive feedback in which climate change is the primary driver of the increasing geese abundance and lake productivity. Our results further suggest that the predicted future warming in the Arctic will continue to have cascading effects on freshwater ecosystems in the region.

We examined the relationship between fossil chironomid assemblages and environmental variables in 30 lakes in southern Finland with particular attention to hypolimnetic oxygen. Ordination techniques (DCA, CCAs) and Monte Carlo permutation tests were used to identify the most important parameters controlling the chironomid distributions. Based on the λ1:λ2 ratios of the variables, the greatest potential for quantitative inferences was with hypolimnetic oxygen (λ1:λ2 = 0.767). Therefore, inference models for past late-winter hypolimnetic oxygen were developed using weighted-averaging partial least squares (WA-PLS) techniques. The best model used one WA-PLS component, with a cross-validated coefficient of determination (r2jack) of 0.72 and a root-mean-squared error of prediction (RMSEP) of 2.351 mg l–1. The model was tested on two short-core sediment sequences. The results indicated that quantitative estimations of hypolimnetic oxygen changes provide a useful tool for palaeolimnology and lake management in assessments of lake ecosystems, and in restoration projects in southern Finland.

Complicated Quaternary sediment strata have been preserved within the ice-divide zone of northern Finland because of weak glacial erosion. Geographic Information System (GIS) databases, 3D modelling and ground penetrating radar surveys were used to construct the 3D structure of unconsolidated sediments and bedrock topography for Kersilö, Sodankylä, to provide information for freshwater management and environmental studies in the mineral exploration area. The model was created using a combination of explicit and implicit modelling covering an area of 10.5 km2. The surficial deposits in the study area are a few metres thicker than their average thickness in northern Finland. They include three till units and four sandy or gravelly units. Fluvial action has repeatedly deposited sorted sediments in the channel valley of the Kitinen river. Basins in the bedrock have preserved thick sediment packages (> 15 m), indicating that the bedrock topography controls the sedimentary features. Aquifers in the area are small and disconnected, and perched aquifers exist due to the low hydraulic conductivity of interlayered tills.

Zoological remains were examined from the sediments of the Pingualuit Crater Lake, Nunavik, Canada. Our objective was to describe past climate events in the area of delayed deglaciation in northernmost Ungava Peninsula. Our record covers 3 separate sections of deglacial and postglacial invertebrate dynamics interrupted by laminated proglacial sediments and a basin-scale erosive slumping event. The abundance of animal remains in the ultra-oligotrophic and extremely deep arctic lake was low, but distinct faunal assemblages were found among the intervals, results implying that they were environmentally heterogeneous. The lowermost fine-grained interval (before 6850 calibrated years before present [cal BP]), revealed that Cladocera Chydorus sphaericus-type and Bosmina (Eubosmina) longispina-type were common in the lake, whereas Chironomidae were relatively rare. The dominance of B. longispina-type showed that planktonic communities were successful at the time, probably indicating more favorable climatic conditions than today soon after the last deglaciation (∼7000 cal BP). In the middle interval (between ∼6850 and 5750 cal BP), chironomids became more common and were dominated by Heterotrissocladius subpilosus-type and Protanypus, taxa that are characteristic of oligotrophic lakes. The extirpation of B. longispina-type suggests that planktonic invertebrate communities were not successful, probably because of predation by Arctic char. The presence of the chironomid Oliveridia tricornis-type during the late Holocene (between ∼4200 and 600 cal BP) suggested general climate cooling. Our paleoclimatic conclusions on the regional environmental history suggest a stationary ice front in the initial stages of the Holocene, favorable climatic conditions in the mid-Holocene and a general late-Holocene cooling. Our records also indicate a subtle increase in nutrient availability throughout the Holocene. The paleoecological record from Pingualuit Crater Lake is valuable in describing the faunal history and biotic resilience in this environmentally extreme lake, which presently contains one of the world's softest and most transparent waters.

The Cu (Pb, Zn) mine of Orijärvi (1757-1956) was the first mining operation in Finland where flotation techniques (1911-1955) were used to enrich ore. Large quantities of tailings were produced. The impacts of past mining activities on the aquatic ecosystem of nearby Lake Orijärvi were studied using a combination of paleolimnological methods (analysis of sedimentary diatom frustules, chrysophycean cysts, metal concentrations and radiometric datings). The acid mine drainage (AMD) - derived metal impact to the lake was found to be the strongest thus far recorded in Finland. Concentrations of Cu, Pb and Zn in sediments are two to three orders of magnitude higher than background values. During the most severe loading phase, there were practically no algae in the lake. Achnanthes minutissima was the hardiest species able to tolerate increased metal contents. The metal load has changed the properties of sediments in such a way that chrysophycean cysts were impossible to identify because of coating and corrosion. Lake water still has elevated heavy metal concentrations, indicating that the impact from the tailings area continues to affect the lake. It has low productivity, and the planktic diatom community is still not developed. The study demonstrates that unremediated mining areas form a major risk to the environment. The damage to aquatic ecosystem can remain severe for decades after the mining activities have ceased.[PUBLICATION ABSTRACT]

Paleoclimate records are crucial for understanding current changes taking place in the Arctic, e.g., the amplified warming and associated changes in sea-ice cover. However, paleoclimate and -oceanographic reconstructions, especially from the high Arctic, are scarce. Here, we present a reconstruction of sea surface and paleoenvironmental conditions from a Holocene marine sediment core collected from a high-Arctic fjord, Isvika Bay, Nordauslandet, Svalbard (79°N). Our proxies include qualitative diatom assemblage data [focusing on the Marginal Ice Zone (MIZ) taxa], a quantitative diatom-based August sea surface temperature (aSST) reconstruction, sediment grain-size distribution, and ice-rafted debris (IRD) spanning the period from 4200 cal. yr BP to the Little Ice Age (LIA) at ca. 200 cal. yr BP. The results reveal cold and stable, glacier-proximal conditions for the beginning of the late Holocene (from 4200 to 2500 cal. yr BP). Then, at 2500 cal. yr BP, the environment shifted into distinctly more fluctuating conditions, where colder and warmer aSSTs alternated in a glacier-distal environment. During the latter part of the late Holocene, sea-ice cover was extensive, yet variable, negatively co-varying with aSST. Based on our diatom data, we observe a clear increase in the influence of Atlantic water in Isvika Bay during the last ca. 600 years.