Browsing by Subject "temperature"

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.

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.

In the process of decomposition soil carbon is transformed into CO2 by microbial respiration, which makes decomposition a key process for understanding carbon cycling an releases of CO2. Since the northern permafrost regions contain half of all belowground carbon and the tundra regions are expected to be markedly affected by climate warming, it is of particular interest to understand how warming will affect decomposition in the tundra. Decomposition is however influenced by many factors, from climatic factors such as temperature and precipitation to the belowground organisms inhabiting the soils and the aboveground system dictating the litter that falls to the ground and is decomposed. Further, grazing has been shown to oppose some of the effects of warming on tundra. In this thesis I analyzed data collected from two long-term field experiments, one in Kilpisjärvi (NW Finland) and the other close to Kangerlussuaq Fjord (SW Greenland), both using fencing for manipulation of grazing regime and open-top chambers for artificial warming. My aim was to not only investigate how warming and grazing affect decomposition, but also to understand whether the magnitude of changes in decomposition can be explained by changes in plant community traits and soil characteristics. I found that in contrast to my hypothesis, warming decreased decomposition in Kangerlussuaq, where the soil was drier and contained less carbon than in Kilpisjärvi. I found no effects of grazing on decomposition, plant community traits nor soil characteristics in neither of the study locations. Neither did I find any consistent associations between changes in decomposition and changes in plant community traits, indicating that the effect of litter quality on decomposition is minor in these areas likely rather limited by climate. I found an association for increased decomposition when plant community C:N ratio and C:P ratio increased as a response to warming, but only in Kilpisjärvi, and since increased plant community C:N and C:P ratios are linked to resistant litter this positive effect is unlikely driven by enhanced litter quality. However, I did find a positive relationship between increased root biomass and increased decomposition as a response to warming that was consistent across areas and grazing regimes, indicating that warming can boost decomposition in different tundra habitats by promoting root growth.

The purpose of tillage is to mulch previous years crop residue and create suitable seedbed for the crop. Tillage can also affect soil temperature properties. Soil temperature affects how fast the seed germinates in soil, how the roots develop, and the microbiological activity of the soil. This study compared the effects of traditional autumn ploughing, autumn chisel plough and zero tillage on soil temperature and moisture content. The project was conducted as a part of Maa- ja vesitekniikan tuki -funded TALMA project, which was carried out in collaboration with MTT. The field experiments and measurements of this study were carried out in Jokioinen at MTT during the period of 1 June 2012 to 06 May 2013. Soil temperature and moisture content were measured continuously at the depth of 10 cm by using one hour measurement frequency. The hypotheses of this research were as follows: Firstly, that the autumn tilled soil warms faster than stubble-covered field. The second hypothesis states, that temperature variation of autumn tilled land is greater than variation of untilled land. Warming of the soil during spring term was compared by setting a target temperature for the ground (+5°C). All tillage treatments reached target temperature within one day. The results demonstrated that the average day temperature of ploughed land was a little colder than stubble covered land in spring. Also the variation of the soil minimum and maximum temperature values was higher in ploughed soil. Based on the results stubble covered land buffers better temperature variation than ploughed land. Stubble covered land does not cool as much as ploughed land during the winter.

Extracellular vesicles (EVs) are a very heterogeneous group of cell originated nanoparticles that act as mediators of intercellular communication. Accurate characterization of EVs is essential to enable their wider use and development as possible biomarkers, drug carriers, and vaccines. There is no validated reference material with EV-like properties currently available. A validated reference material would improve the reliability and reproducibility of EV studies. Nanoerythrosomes (NanoE) have been studied as a possible option for biological reference material. We aimed to further characterize and compare properties of NanoEs and erythrocyte-derived EVs (EryEV) and assess their stability concerning concentration and size distribution at most commonly applied storage temperatures, +4°C, -20°C, and -80°C for 12 weeks. Characterization was done using nanoparticle tracking analysis and flow cytometry. In addition, we studied the surface protein expression including CD235a, CD47, and CD41 of NanoEs and EryEV and conducted a preliminary cellular uptake test using PC-3 cells, CFSE-labeled NanoE, and EryEV particles. For both, NanoE and EryEV samples, 20°C was the worst storage condition. NanoEs stay stable at +4°C for a month and at -80°C, there were some drops in concentration during the 12 weeks of the experiment. EryEVs stay stable at +4°C and -80°C for 12 weeks. Both NanoE and EryEV particles seemed to be taken into the PC-3 cells, but due to problems with autofluorescence we conclude that confirming studies with different labeling protocols or another method need to be conducted. Both NanoEs and EryEVs samples had a significant number of CD47-positive particles.

Lepidurus arcticus (Pallas, 1793) is a keystone species in High Arctic ponds, which are exposed to a wide range of environmental stressors. This thesis provides information on the ecology of this little studied species by paying particular focus on the sensitivity of L. arcticus to acidification and climate change. Respiration, reproduction, olfaction, morphology, salinity and pH tolerance of the species were studied in the laboratory and several environmental parameters were measured in its natural habitats in Arctic ponds. Current global circulation models predict 2–2.4 °C increase in summer temperatures on Spitsbergen, Svalbard, Norway. The L. arcticus respiration activity was tested at different temperatures (3.5, 10, 16.5, 20, 25 and 30 °C). The results show that L. arcticus is clearly adapted to live in cold water and have a temperature optimum at +10 °C. This species should be considered as stenothermal, because it seems to be able to live only within a narrow temperature range. L. arcticus populations seem to have the capacity to respond to the ongoing climate change on Spitsbergen. Changes can be seen in the species' reproductive capacity and in the individuals' body size when comparing results with previous studies on Spitsbergen and in other Arctic areas. Effective reproduction capacity was a unique feature of the L. arcticus populations on Spitsbergen. L. arcticus females reached sexual maturity at a smaller body size and sexual dimorphism appeared in smaller animals on Spitsbergen than anywhere else in the subarctic or Arctic regions. L. arcticus females were able to carry more eggs (up to 12 eggs per female) than has been observed in previous studies. Another interesting feature of L. arcticus on Spitsbergen was their potential to grow large, up to 39.4 mm in total length. Also cannibalistic behaviour seemed to be common on Spitsbergen L. arcticus populations. The existence of different colour morphs and the population-level differences in morphology of L. arcticus were unknown, but fascinating characteristic of this species. Spitsbergen populations consisted of two major (i.e. monochrome and marbled) and several combined colour morphs. Third interesting finding was a new disease for science which activated when the water temperature rose. I named this disease to Red Carapace Disease (RCD). This High Arctic crustacean lives in ponds between the Arctic Ocean and glaciers, where the marine environment has a strong impact on the terrestrial and freshwater ecosystems. The tolerance of L. arcticius to increased water salinity was determined by a LC50 -test. No mortality occurred during the 23 day exposure at low 1–2 ‰ water salinity. A slight increase in water salinity (to 1 ‰) speeded up the L. arcticus shell replacement. The observations from natural populations supported the hypothesis that the size of the animals increases considerably in low 1.5 ‰ salt concentrations. Thus, a small increase in water salinity seems to have a positive impact on the growth of this short-lived species. Acidification has been a big problem for many crustaceans, invertebrates and fishes for several decades. L. arcricus does not make an exception. Strong acid stress in pH 4 caused a high mortality of mature L. arcticus females. The critical lower limit of pH was 6.1 for the survival of this acid sensitive species. Thus, L. arcticus populations are probably in danger of extinction due to acidification of three ponds on Spitsbergen. A slight drop (0.1–1.0) in pH values can wipe out these L. arcticus populations. The survival of L. arcticus was strongly related to: (1) the water pH, (2) total organic carbon (TOC) and pH interaction, (3) the water temperature and (4) the water salinity. Water pH and TOC values should be monitored in these ponds and the input of acidifying substances in ponds should be prevented.

Climate change will cause an especially pronounced temperature rise in the northern latitudes. These sensitive ecosystems will likely experience significant, rapid, and even irreversible changes. The outbreaks of autumnal moth and winter moth in northern Fennoscandia have already been documented to be prolonged and spread out to new geographical areas. The two species share very similar ecological traits as forest pests, whose population densities fluctuate in approximately ten-year cycles. They can defoliate vast mountain birch forests during the epidemic peaks. This study focused on jointly analyzing the population dynamics of these two geometrids and the regulatory effects of winter temperatures. The aim was to see whether the populations fluctuate synchronously, does elevation have an effect in species occurrence, and can winter temperature variables be used to model the population development of the species. The study was based on a 33-year long light trap time series from Värriö research station and local climate data from Finnish Meteorological Institute. The data was analyzed with time series analysis methods. Population fluctuations of autumnal moth and winter moth were observed to be well synchronized regardless of the difference in magnitude of the actual catch numbers. Both species occurred in less numbers with the increase in elevation. Winter moth catch numbers had an increasing trend whereas autumnal moth catch numbers were declining. The trends also differed with elevation. Winter moth was most prominently increasing in mountain birch belt and the decrease in autumnal moth numbers was most significant in traps outside of the mountain birch belt. The regulatory effect of winter temperature variables could be modeled only for winter moth with the methods utilized in this study. The minimum temperatures of December, January, and April seemed to have the most notable effect on the population development. Temperatures in December and January featured the most significant increasing trends based on many different temperature variables examined in this study. This points to the conclusion of winter moth having good potential to increase its abundance in the future.