Browsing by Subject "temperature"

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  • Arppe, Laura; Kurki, Eija; Wooller, Matthew J.; Luoto, Tomi P.; Zajaczkowski, Marek; Ojala, Antti E. K. (2017)
    The oxygen isotope composition of chironomid head capsules in a sediment core spanning the past 5500 years from Lake Svartvatnet in southern Spitsbergen was used to reconstruct the oxygen isotope composition of lake water (O-18(lw)) and local precipitation. The O-18(lw) values display shifts from the baseline variability consistent with the timing of recognized historical climatic episodes, such as the Roman Warm Period, the Dark Ages Cold Period and the Little Ice Age'. The highest values of the record, ca. 3 parts per thousand above modern O-18(lw) values, occur at ca. 1900-1800 cal. yr BP. Three negative excursions increasing in intensity toward the present, at 3400-3200, 1250-1100, and 350-50 cal. yr BP, are tentatively linked to roughly synchronous episodes of increased glacier activity and general cold spells around the northern North Atlantic. Their manifestation in the Svartvatnet O-18(lw) record not only testify to the sensitivity and potential of high Arctic lacustrine O-18(chir) records in tracking terrestrial climate evolution but also highlight nonlinear dynamics within the northern North Atlantic hydroclimatic system. The Little Ice Age' period at 350-50 cal. yr BP displays a remarkable 8-9 parts per thousand drop in O-18(lw) values, construed to predominantly represent significantly decreased winter temperatures during a period of increased seasonal differences and extended sea ice cover inducing changes in moisture source regions.
  • Kylä-Puhju, Maria; Ruusunen, Marita; Puolanne, Eero (Elsevier, 2005)
    The activity of glycogen debranching enzyme (GDE) was studied in relation to pH value and temperature in porcine masseter and longissimus dorsi muscles. A glycogen limit dextrin was used as the substrate for GDE, and the enzyme was derived from raw meat extracts. In both muscles, the pH only weakly affected on activity of GDE at the pH values found in carcasses post-slaughter. However, the activity of GDE decreased strongly (P < 0.001) when the temperature decreased from values of 39 °C and 42 °C found just after slaughter to values of 4 °C and 15 °C found during cooling. In both muscles the activity of GDE began to fall at temperatures below 39 °C and was almost zero when the temperature decreased to below 15 °C. Thus, the activity of GDE may control the rate of glycogenolysis and glycolysis, but does not block rapid glycolysis and pH decrease when the temperature is high. This may be important in PSE meat, where the pH decreases rapidly at high temperatures, but rapid cooling could limit the activity of GDE and thus glycogenolysis. As expected, GDE was more active in the light longissimus dorsi muscle than in the dark masseter muscle.
  • Luoto, Tomi P.; Kivila, E. Henriikka; Kotrys, Bartosz; Plociennik, Mateusz; Rantala, Marttiina; Nevalainen, Liisa (2020)
    Independent Arctic records of temperature and precipitation from the same proxy archives are rare. Nevertheless, they are important for providing detailed information on long-term climate changes and temperature-precipitation relationships in the context of large-scale atmospheric dynamics. Here, we used chironomid and cladoceran fossil assemblages to reconstruct summer air-temperature and water-level changes, during the past 400 years, in a small lake located in Finnish Lapland. Temperatures remained persistently cold over the Little Ice Age (LIA), but increased in the 20th century. After a cooler phase in the 1970s, the climate rapidly warmed to the record-high temperatures of the most recent decades. The lake-level reconstruction suggested persistently wet conditions for the LIA, followed by a dry period between similar to 1910 and 1970 CE, when the lake apparently became almost dry. Since the 1980s, the lake level has returned to a similar position as during the IAA. The temperature development was consistent with earlier records, but a significant local feature was found in the lake-level reconstruction the LIA appears to have been continuously wet, without the generally depicted dry phase during the 18th and 19th centuries. Therefore, the results suggest local precipitation patterns and enforce the concept of spatially divergent LIA conditions.
  • Koskela, Elina (Helsingin yliopisto, 2019)
    Tiivistelmä/Referat – Abstract This study investigates temperature data that Posiva Oy has from the Olkiluoto and ONKALO® sites. The aim of the study was to create a unifying data classification for the existing temperature measurements, give an estimate of the initial undisturbed bedrock temperature and temperature gradient and model the temperature profiles in 3D. The thermal related issues, which the repository will undergo once in operating are significant and have fundamental contribution to the evolution of the repository, creating a need in such a study. Posiva Oy has temperature data obtained with four main methods; Geophysical drillhole loggings, Posiva flow log (PFL) measurements, thermal properties (TERO) measurements and Antares measurements. The data classification was carried out by creating a platform of quality aspects affecting the measurements. The classification was then applied for all the available data by inspecting the measurement specifics of each configuration and by observing the temperature/depth profiles with WellCad software. According to the specifics of each individual measurement the data was classified into three groups: A= the best data, recommended for further use, and which fulfils all quality criteria, B= data that should be used with reservation and which only partly fulfils quality criteria, and C= unusable data. Only data that showed no major disturbance within the temperature/depth profile (class A or B) were used in this study. All the temperature/depth data was corrected to the true vertical depth. The initial undisturbed average temperature of Olkiluoto bedrock at the deposition depth of 412 m and the temperature gradient, according to the geophysical measurements, PFL measurements (without pumping), TERO measurements and Antares measurements were found to be 10.93 ± 0.09°C and 1.47°C/100m, 10.85 ± 0.02°C and 1.43°C/100m, 10.60 ± 0.08°C and 1.65°C/100m, and 10.75°C and 1.39°C/100m, respectively. The 3D layer models presented in this study were generated by using Leapfrog Geo software. From the model a 10.5 – 12°C temperature range was obtained for the deposition depth of 412 – 432 m. The models indicated clear temperature anomalies in the volume of the repository. These anomalies showed relationship between the location of the major brittle fault zones (BFZ) of Olkiluoto island. Not all observed anomalies could be explained by a possible cause. Uncertainties within the modelling phase should be taken into consideration in further interpretations. By combining an up-to-date geological model and hydraulic model of the area to the temperature models presented here, a better understanding of the temperature anomalies and a clearer over all understanding of the thermal conditions of the planned disposal location will be achieved. Based on this study a uniform classification improves the usability of data and leads into a better understanding of the possibilities and weaknesses within it. The initial bedrock temperature and the temperature gradient in Olkiluoto present thermally a relatively uniform formation. The estimates of the initial bedrock temperatures and the temperature gradient presented in this study, endorse previous estimates. Presenting the classified temperature data in 3D format generated good results in the light of thermal dimensioning of Olkiluoto by showing distinct relationships between previously created brittle fault zone (fracture zone) models. The views and opinions presented here are those of the author, and do not necessarily reflect the views of Posiva.
  • Camarena‐Gómez, María Teresa; Ruiz‐González, Clara; Piiparinen, Jonna; Lipsewers, Tobias; Sobrino, Cristina; Logares, Ramiro; Spilling, Kristian (American Society of Limnology and Oceanography, 2021)
    Limnology and Oceanography 66: 1, 255-271
    In parts of the Baltic Sea, the phytoplankton spring bloom communities, commonly dominated by diatoms, are shifting toward the co-occurrence of diatoms and dinoflagellates. Although phytoplankton are known to shape the composition and function of associated bacterioplankton communities, the potential bacterial responses to such a decrease of diatoms are unknown. Here we explored the changes in bacterial communities and heterotrophic production during the spring bloom in four consecutive spring blooms across several sub-basins of the Baltic Sea and related them to changes in environmental variables and in phytoplankton community structure. The taxonomic structure of bacterioplankton assemblages was partially explained by salinity and temperature but also linked to the phytoplankton community. Higher carbon biomass of the diatoms Achnanthes taeniata, Skeletonema marinoi, Thalassiosira levanderi, and Chaetoceros spp. was associated with more diverse bacterial communities dominated by copiotrophic bacteria (Flavobacteriia, Gammaproteobacteria, and Betaproteobacteria) and higher bacterial production. During dinoflagellate dominance, bacterial production was low and bacterial communities were dominated by Alphaproteobacteria, mainly SAR11. Our results suggest that increases in dinoflagellate abundance during the spring bloom will largely affect the structuring and functioning of the associated bacterial communities. This could decrease pelagic remineralization of organic matter and possibly affect the bacterial grazers communities.
  • Olofsson, Malin; Suikkanen, Sanna; Kobos, Justyna; Wasmund, Norbert; Karlson, Bengt (Elsevier, 2020)
    Harmful Algae
    Almost every summer, dense blooms of filamentous cyanobacteria are formed in the Baltic Sea. These blooms may cause problems for tourism and ecosystem services, where surface accumulations and beach fouling are commonly occurring. Future changes in environmental drivers, including climate change and other anthropogenic disturbances, may further enhance these problems. By compiling monitoring data from countries adjacent to the Baltic Sea, we present spatial and temporal genus-specific distribution of diazotrophic filamentous cyanobacteria (Nostocales) during four decades (1979–2017). While the summer surface salinity decreased with a half up to one unit, the surface temperature in July-August increased with 2–3 °C in most sub-basins of the Baltic Sea, during the time period. The biovolumes of the toxic Nodularia spumigena did not change in any of the sub-basins during the period. On the other hand, the biovolume of the non-toxic Aphanizomenon sp. and the potentially toxic Dolichospermum spp. increased in the northern parts of the Baltic Sea, along with the decreased salinity and elevated temperatures, but Aphanizomenon sp. decreased in the southern parts despite decreased salinity and increased temperatures. These contradictory changes in biovolume of Aphanizomenon sp. between the northern and southern parts of the Baltic Sea may be due to basin-specific effects of the changed environmental conditions, or can be related to local adaptation by sub-populations of the genera. Overall, this comprehensive dataset presents insights to genus-specific bloom dynamics by potentially harmful diazotrophic filamentous cyanobacteria in the Baltic Sea. Highlights • Biovolumes of bloom-forming cyanobacteria during four decades in the Baltic Sea. • Aphanizomenon sp. has increased with decreased salinity in the Bothnian Sea. • Dolichospermum spp. has increased with temperature in Bothnian Sea. • The total biovolume of Nostocales has decreased in the Southern Baltic Proper. • The biovolume of the toxic Nodularia spumigena has not changed since the 1980s.
  • Mammola, Stefano; Piano, Elena; Cardoso, Pedro; Vernon, Philippe; Dominguez-Villar, David; Culver, David C.; Pipan, Tanja; Isaia, Marco (2019)
    Scientists of different disciplines have recognized the valuable role of terrestrial caves as ideal natural laboratories in which to study multiple eco-evolutionary processes, from genes to ecosystems. Because caves and other subterranean habitats are semi-closed systems characterized by a remarkable thermal stability, they should also represent insightful systems for understanding the effects of climate change on biodiversity in situ. Whilst a number of recent advances have demonstrated how promising this fast-moving field of research could be, a lack of synthesis is possibly holding back the adoption of caves as standard models for the study of the recent climatic alteration. By linking literature focusing on physics, geology, biology and ecology, we illustrate the rationale supporting the use of subterranean habitats as laboratories for studies of global change biology. We initially discuss the direct relationship between external and internal temperature, the stability of the subterranean climate and the dynamics of its alteration in an anthropogenic climate change perspective. Owing to their evolution in a stable environment, subterranean species are expected to exhibit low tolerance to climatic perturbations and could theoretically cope with such changes only by shifting their distributional range or by adapting to the new environmental conditions. However, they should have more obstacles to overcome than surface species in such shifts, and therefore could be more prone to local extinction. In the face of rapid climate change, subterranean habitats can be seen as refugia for some surface species, but at the same time they may turn into dead-end traps for some of their current obligate inhabitants. Together with other species living in confined habitats, we argue that subterranean species are particularly sensitive to climate change, and we stress the urgent need for future research, monitoring programs and conservation measures.
  • Fronzek, Stefan; Johansson, Margareta; Christensen, Torben R.; Carter, Timothy R.; Friborg, Thomas; Luoto, Miska (Finnish Environment Institute, 2009)
    Reports of the Finnish Environment Institute 3/2009
  • Yi, Chuixiang; Ricciuto, Daniel; Li, Runze; Wolbeck, John; Xu, Xiyan; Nilsson, Mats; Aires, Luis; Albertson, John D.; Ammann, Christof; Arain, M. Altaf; de Araujo, Alessandro C.; Aubinet, Marc; Aurela, Mika; Barcza, Zoltan; Barr, Alan; Berbigier, Paul; Beringer, Jason; Bernhofer, Christian; Black, Andrew T.; Bolstad, Paul V.; Bosveld, Fred C.; Broadmeadow, Mark S. J.; Buchmann, Nina; Burns, Sean P.; Cellier, Pierre; Chen, Jiquan; Ciais, Philippe; Clement, Robert; Cook, Bruce D.; Curtis, Peter S.; Dail, D. Bryan; Dellwik, Ebba; Delpierre, Nicolas; Desai, Ankur R.; Dore, Sabina; Dragoni, Danilo; Drake, Bert G.; Dufrene, Eric; Dunn, Allison; Elbers, Jan; Eugster, Werner; Falk, Matthias; Feigenwinter, Christian; Flanagan, Lawrence B.; Foken, Thomas; Frank, John; Fuhrer, Juerg; Gianelle, Damiano; Goldstein, Allen; Goulden, Mike; Granier, Andre; Gruenwald, Thomas; Gu, Lianhong; Guo, Haiqiang; Hammerle, Albin; Han, Shijie; Hanan, Niall P.; Haszpra, Laszlo; Heinesch, Bernard; Helfter, Carole; Hendriks, Dimmie; Hutley, Lindsay B.; Ibrom, Andreas; Jacobs, Cor; Johansson, Torbjoern; Jongen, Marjan; Katul, Gabriel; Kiely, Gerard; Klumpp, Katja; Knohl, Alexander; Kolb, Thomas; Kutsch, Werner L.; Lafleur, Peter; Laurila, Tuomas; Leuning, Ray; Lindroth, Anders; Liu, Heping; Loubet, Benjamin; Manca, Giovanni; Marek, Michal; Margolis, Hank A.; Martin, Timothy A.; Massman, William J.; Matamala, Roser; Matteucci, Giorgio; McCaughey, Harry; Merbold, Lutz; Meyers, Tilden; Migliavacca, Mirco; Miglietta, Franco; Misson, Laurent; Moelder, Meelis; Moncrieff, John; Monson, Russell K.; Montagnani, Leonardo; Montes-Helu, Mario; Moors, Eddy; Moureaux, Christine; Mukelabai, Mukufute M.; Munger, J. William; Myklebust, May; Nagy, Zoltan; Noormets, Asko; Oechel, Walter; Oren, Ram; Pallardy, Stephen G.; Kyaw, Tha Paw U.; Pereira, Joao S.; Pilegaard, Kim; Pinter, Krisztina; Pio, Casimiro; Pita, Gabriel; Powell, Thomas L.; Rambal, Serge; Randerson, James T.; von Randow, Celso; Rebmann, Corinna; Rinne, Janne; Rossi, Federica; Roulet, Nigel; Ryel, Ronald J.; Sagerfors, Jorgen; Saigusa, Nobuko; Sanz, Maria Jose; Mugnozza, Giuseppe-Scarascia; Schmid, Hans Peter; Seufert, Guenther; Siqueira, Mario; Soussana, Jean-Francois; Starr, Gregory; Sutton, Mark A.; Tenhunen, John; Tuba, Zoltan; Tuovinen, Juha-Pekka; Valentini, Riccardo; Vogel, Christoph S.; Wang, Shaoqiang; Wang, Weiguo; Welp, Lisa R.; Wen, Xuefa; Wharton, Sonia; Wilkinson, Matthew; Williams, Christopher A.; Wohlfahrt, Georg; Yamamoto, Susumu; Yu, Guirui; Zampedri, Roberto; Zhao, Bin; Zhao, Xinquan (2010)
  • Eyres, Alison; Eronen, Jussi T.; Hagen, Oskar; Boehning-Gaese, Katrin; Fritz, Susanne A. (2021)
    Climatic niches describe the climatic conditions in which species can persist. Shifts in climatic niches have been observed to coincide with major climatic change, suggesting that species adapt to new conditions. We test the relationship between rates of climatic niche evolution and paleoclimatic conditions through time for 65 Old-World flycatcher species (Aves: Muscicapidae). We combine niche quantification for all species with dated phylogenies to infer past changes in the rates of niche evolution for temperature and precipitation niches. Paleoclimatic conditions were inferred independently using two datasets: a paleoelevation reconstruction and the mammal fossil record. We find changes in climatic niches through time, but no or weak support for a relationship between niche evolution rates and rates of paleoclimatic change for both temperature and precipitation niche and for both reconstruction methods. In contrast, the inferred relationship between climatic conditions and niche evolution rates depends on paleoclimatic reconstruction method: rates of temperature niche evolution are significantly negatively related to absolute temperatures inferred using the paleoelevation model but not those reconstructed from the fossil record. We suggest that paleoclimatic change might be a weak driver of climatic niche evolution in birds and highlight the need for greater integration of different paleoclimate reconstructions.
  • Pilla, Rachel M.; Williamson, Graig E.; Adamovich, Boris V.; Adrian, Rita; Anneville, Orlane; Chandra, Sudeep; Colom-Montero, William; Devlin, Shawn P.; Dix, Margaret A; Dokulil, Martin T.; Gaiser, Evelyn E.; Girdner, Scott F.; Hambright, David K.; Hamilton, David P.; Havens, Karl; Hessen, Dag O.; Higgins, Scott N.; Huttula, Timo H.; Huuskonen, Hannu; Isles, Peter D. F.; Joehnk, Klaus D.; Jones, Ian D.; Keller, Wendel Bill; Knoll, Lesley B.; Korhonen, Johanna; Kraemer, Benjamin M.; Leavitt, Peter R.; Lepori, Fabio; Luger, Martin S.; Maberly, Stephen C.; Melack, John M.; Melles, Stephanie J.; Müller-Navarra, Dörthe C.; Pierson, Don C.; Pislegina, Helen V.; Plisnier, Pierre-Denis; Richardson, David C.; Rimmer, Alon; Rogora, Michela; Rusak, James A.; Sadro, Steven; Salmaso, Nico; Saros, Jasmine E.; Saulnier-Talbot, Émilie; Schindler, Daniel E.; Schmid, Martin; Shimaraeva, Svetlana V.; Silow, Eugene A.; Sitoki, Lewis M.; Sommaruga, Ruben; Straile, Dietmar; Strock, Kristin E.; Thiery, Wim; Timofeyev, Maxim A.; Verburg, Piet; Vinebrooke, Rolf D.; Weyhenmeyer, Gesa A.; Zadereev, Egor (Rebekah A. Canada, 2020)
    Scientific Reports 10, 1 (2020), 20514
    Globally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970–2009) summertime vertical temperature profiles in lakes across the world to examine trends and drivers of whole-lake vertical thermal structure. We found significant increases in surface water temperatures across lakes at an average rate of + 0.37 °C decade−1, comparable to changes reported previously for other lakes, and similarly consistent trends of increasing water column stability (+ 0.08 kg m−3 decade−1). In contrast, however, deepwater temperature trends showed little change on average (+ 0.06 °C decade−1), but had high variability across lakes, with trends in individual lakes ranging from − 0.68 °C decade−1 to + 0.65 °C decade−1. The variability in deepwater temperature trends was not explained by trends in either surface water temperatures or thermal stability within lakes, and only 8.4% was explained by lake thermal region or local lake characteristics in a random forest analysis. These findings suggest that external drivers beyond our tested lake characteristics are important in explaining long-term trends in thermal structure, such as local to regional climate patterns or additional external anthropogenic influences.
  • Fronzek, Stefan; Carter, Timothy R.; Pirttioja, Nina; Alkemade, Rob; Audsley, Eric; Bugmann, Harald; Flörke, Martina; Holman, Ian; Honda, Yasushi; Ito, Akihiko; Janes-Bassett, Victoria; Lafond, Valentine; Leemans, Rik; Mokrech, Marc; Nunez, Sarahi; Sandars, Daniel; Snell, Rebecca; Takahashi, Kiyoshi; Tanaka, Akemi; Wimmer, Florian; Yoshikawa, Minoru (Springer, 2019)
    Regional Environmental Change
    Responses to future changes in climatic and socio-economic conditions can be expected to vary between sectors and regions, reflecting differential sensitivity to these highly uncertain factors. A sensitivity analysis was conducted using a suite of impact models (for health, agriculture, biodiversity, land use, floods and forestry) across Europe with respect to changes in key climate and socio-economic variables. Depending on the indicators, aggregated grid or indicative site results are reported for eight rectangular sub-regions that together span Europe from northern Finland to southern Spain and from western Ireland to the Baltic States and eastern Mediterranean, each plotted as scenario-neutral impact response surfaces (IRSs). These depict the modelled behaviour of an impact variable in response to changes in two key explanatory variables. To our knowledge, this is the first time the IRS approach has been applied to changes in socio-economic drivers and over such large regions. The British Isles region showed the smallest sensitivity to both temperature and precipitation, whereas Central Europe showed the strongest responses to temperature and Eastern Europe to precipitation. Across the regions, sensitivity to temperature was lowest for the two indicators of river discharge and highest for Norway spruce productivity. Sensitivity to precipitation was lowest for intensive agricultural land use, maize and potato yields and Scots pine productivity, and highest for Norway spruce productivity. Under future climate projections, North-eastern Europe showed increases in yields of all crops and productivity of all tree species, whereas Central and East Europe showed declines. River discharge indicators and forest productivity (except Holm oak) were projected to decline over southern European regions. Responses were more sensitive to socio-economic than to climate drivers for some impact indicators, as demonstrated for heat-related mortality, coastal flooding and land use.
  • Mytty, Tuukka (Helsingfors universitet, 2013)
    Does carbon dioxide predict temperature? No it does not, in the time period of 1880-2004 with the carbon dioxide and temperature data used in this thesis. According to the Inter Governmental Panel on Climate Change(IPCC) carbon dioxide is the most important factor in raising the global temperature. Therefore, it is reasonable to assume that carbon dioxide truly predicts temperature. Because this paper uses observational data it has to be kept in mind that no causality interpretation can be made, only predictive inferences. The data is from the years 1880-2004 and consists of carbon dioxide emissions and temperature anomalies, the base period for the anomalies is 1961-1990. The main analysis method is the cointegrated VAR model but also the standard VAR model is used. The variables were tested for possible unit roots and it was found that there were unit roots present. Then the variables were tested for the cointegrating rank and here the analysis divided into three parts. One, with the assumptions that the variables are integrated of order one, a constant as a deterministic term and one cointegrating relation. Two, variables are allowed to be integrated of order two, a linear trend as a deterministic term and one cointegrating relation. Three, based on some weak evidence there was a result that variables weren’t cointegrated and the analysis could be done in differences. In the first the case it the result was that carbon dioxide doesn’t predict temperature but actually temperature predicted carbon dioxide, the second version gave the same result. In the third case neither one of the variables predicted the other one. These results go against the what is considered as the common consensus in the subject matter of climate change.
  • Finér, Leena; Lepistö, Ahti; Karlsson, Kristian; Räike, Antti; Härkönen, Laura; Huttunen, Markus; Joensuu, Samuli; Kortelainen, Pirkko; Mattsson, Tuija; Piirainen, Sirpa; Sallantaus, Tapani; Sarkkola, Sakari; Tattari, Sirkka; Ukonmaanaho, Liisa (Elsevier, 2021)
    Science of The Total Environment 762 (2021), 144098
    More reliable assessments of nutrient export to surface waters and the Baltic Sea are required to achieve good ecological status of all water bodies. Previous nutrient export estimates have recently been questioned since they did not include the long-term impacts of drainage for forestry. We made new estimates of the total nitrogen (N), total phosphorus (P) and total organic carbon (TOC) export from forests to surface waters at different spatial scales in Finland. This was done by formulating statistical equations between streamwater concentrations and climate, soil, forest management and runoff variables and spatial data on catchment characteristics. The equations were based on a large, long-term runoff and streamwater quality dataset, which was collected from 28 pristine and 61 managed boreal forest catchments located around Finland. We found that the concentrations increased with temperature sum (TS), i.e. from north to south. Nitrogen, P and TOC concentrations increased with the proportion of drained areas in the catchment; those of N and TOC also increased with the proportion of peatlands. In contrast, with the increasing concentrations of N and TOC with time, P concentrations showed a decreasing trend over the last few decades. According to our estimates, altogether 47,300 Mg of N, 1780 Mg of P and 1814 Gg of TOC is transported from forest areas to surface waters in Finland. Forest management contributes 17% of the N export, 35% of the P export and 12% of the TOC export. Our new forest management export estimates for N and P are more than two times higher than the old estimates used by the environment authorities. The differences may be explained by the long-term impact of forest drainage. The spatial results indicate that peatland forests are hotspots for N, P and TOC export, especially in the river basins draining to the Gulf of Bothnia.
  • Brittain, John E.; Heino, Jani; Friberg, Nikolai; Aroviita, Jukka; Kahlert, Maria; Karjalainen, Satu‐Maaria; Keck, François; Lento, Jennifer; Liljaniemi, Petri; Mykrä, Heikki; Schneider, Susanne C.; Ylikörkkö, Jukka (Blackwell Scientific, 2022)
    Freshwater Biology
    1. Arctic freshwaters support biota adapted to the harsh conditions at these latitudes, but the climate is changing rapidly and so are the underlying environmental filters. Currently, we have limited understanding of broad-scale patterns of Arctic riverine biodiversity and the correlates of α- and β-diversity. 2. Using information from a database set up within the scope of the Arctic Council's Conservation of Arctic Flora and Fauna Circumpolar Biodiversity Monitoring Plan, we analysed patterns and correlates of α- and β-diversity in benthic diatom and macroinvertebrate communities across northern Norway, Sweden, and Finland. We analysed variation in total β-diversity and its replacement and richness difference components in relation to location of the river reach and its drainage basin (Baltic Sea in the south, the Barents Sea in the east and the north, and the Norwegian Sea in the west), in addition to climate and environmental variables. 3. In both macroinvertebrates and diatoms, the replacement and richness difference components showed wide variation. For macroinvertebrates, the richness difference component was the more important, whereas for diatoms, the replacement component was the more important in contributing to variation in β-diversity. There was no significant difference in β-diversity between the three main drainage basins, but species composition differed among the drainage basins. 4. Based on the richness difference component of β-diversity, climate variables were most strongly associated with community variation in macroinvertebrates. In diatoms, both environmental and climate variables were strongly correlated with community compositional variation. In both groups, there were also significant differences in α-diversity among the three main drainage basins, and several taxa were significant indicators of one of these drainage basins. Alpha diversity was greater in areas with a continental climate, while the oceanic areas in the west harboured greatly reduced flora and fauna. 5. The correlates of biodiversity were relatively similar in macroinvertebrates and diatoms. Climate variables, in particular temperature, were the most strongly associated with biodiversity patterns in the Arctic rivers of Fennoscandia. Sedimentary geology may be associated with increased productivity and, to a lesser extent, with sensitivity to acidification. There was considerable variation in community composition across Arctic Fennoscandia, indicating the necessity of protecting several stream reaches or even whole catchments within each region to conserve total riverine biodiversity. Furthermore, it is likely that the predicted changes in temperature in Arctic areas will influence riverine diversity patterns across Fennoscandia.
  • Räisänen, Jouni (2019)
    The effect of atmospheric circulation on temperature variability and trends in Finland in 1979–2018 is studied using a trajectory-based method. On the average 81% of the detrended interannual variance of monthly mean temperatures is explained by the start points of the three-dimensional trajectories, with the best performance in autumn and winter. Atmospheric circulation change is only found to have had a small impact on the observed annual mean temperature trends, but it has considerably modified the trends in individual months. In particular, changes in circulation explain the lack of observed warming in June, the very modest warming in October in southern Finland, and about a half of the very large warming in December. The residual trends obtained by subtracting the circulation-related change from observations are robustly positive in all months of the year, exhibit a smoother seasonal cycle, and agree better with the multi-model mean temperature trends from models in the 5th Coupled Model Intercomparison Project (CMIP5). Nevertheless, some differences between the residual trends and the average CMIP5 trends are also found.
  • Hänninen, Heikki; Pelkonen, Paavo (Suomen metsätieteellinen seura, 1988)
  • Hänninen, Heikki (Suomen metsätieteellinen seura, 1987)
  • Peng, Li Qing; Tang, Min; Liao, Jia Hong; Liang, Shi Yuan; Gan, Li Tao; Hua, Ke Jun; Chen, Yan; Li, Hong; Chen, Wei; Merilä, Juha (2020)
    Organisms living in extreme environments, such as amphibians inhabiting the Tibetan plateau, are faced with a magnitude of potentially strong selection pressures. With an average elevation exceeding 4500 m, the Tibetan plateau is mainly characterized by low temperatures, but little is known about the influence of this factor on the growth, development, and behaviour of amphibian larvae living in this environment. Using a common garden experiment, we studied the influence of temperatures on the early growth and development of tadpoles of the Tibetan brown frog (Rana kukunoris) endemic to the eastern Tibetan plateau. We discovered that temperature had a significant influence on early growth and development of the tadpoles, with those undergoing high-temperature treatment growing and developing faster than their siblings from a low-temperature treatment. However, high-altitude individuals grew faster than low-altitude individuals at low temperatures. while the opposite was true at high temperatures. These results support the temperature adaptation hypothesis, as tadpoles' growth and developmental rates were maximized at the temperatures experienced in their native environments. These results suggest that variation in ambient temperature. combined with evolutionary adaptation to temperature of local environments, is probably one of the most critical environmental factors shaping altitudinal differences in the growth and development of amphibian larvae on the Tibetan plateau.
  • Folestad, Magdalena (Helsingin yliopisto, 2022)
    The study is sought to study how and if the environment has changed in eastern Finnish Lapland in a long-term perspective. Variables related to the current state of the environment, are atmospheric composition and aerosols, meteorology, and biology. The study is based on measurements from Värriö Subarctic Research station for the years 1973 to 2021. Included in atmospheric composition, are the atmospheric anthropogenic gas concentrations of CO, NOx, O3 and SO2. SO2 is also used in a proxy to estimate H2SO4 concentrations. Decreasing long-term trends are found for CO, NOx, SO2 and H2SO4. The decreasing emissions from Kola peninsula, is the cause for long-term decrease of SO2, which result in decreasing H2SO4 concentrations. Results of particle size distribution show an increasing concentration of small particles and decrease of large particles. Decline of particles leads to less NPF, CCN and will resultingly influence cloud properties. Air temperature has increased 2.38 °C and snow cover days have decreased by three weeks, between 1975 and 2021. Snow depth and precipitation show less significant changes. Heat sum have from 1981 to 2021 increased with 247 °C days, indicating more active and growing trees. Birch leave development show indications of leave burst and developed leaves to occur at earlier date, over the years 1981-2021. Grouses, shorebirds, and cavity-nesters show large inter-annual variations. Some of the bird species appears to benefit from environmental changes while others appear to have difficulty adapting.