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(2024)Kiertotaloutta on esitetty ratkaisuksi rakennussektorin kestävyyshaasteisiin, sillä kiertotalouden perusstrategiat tehostavat rakennus- ja purkujätteen sisältämien materiaalien hyötykäyttöä, vähentävät syntyvän jätteen määrää ja kasvattavat resurssitehokkuutta. Suomi on sitoutunut hyödyntämään kaikesta rakennus- ja purkujätteestä materiaalina vähintään 70 %, mutta tavoitteen saavuttaminen vaatii lisätoimia. Kaupungeilla on merkittävä rooli kiertotalouden mukaisen materiaalikierron edistämisessä. Tämä tutkielma liittyy Lahden kaupungin organisoimaan Niemi Living Lab -pilottihankkeeseen, jossa suunnitellaan Lahdessa sijaitsevan Niemen alueen muutosta teollisuusalueesta asuin- ja virkistysalueeksi. Hankkeen perusajatuksena on miettiä, miten alueen purkumateriaalit saataisiin hyödynnettyä mahdollisimman tehokkaasti kiertotalouden periaatteita noudattaen. Tutkimuksen tavoitteena oli tehdä yleistason kartoitus alueelta ensimmäisenä purettavien tehdasrakennusten purkumateriaaleista ja niiden uudelleenkäyttö- ja kierrätysmahdollisuuksista sekä selvittää, millaisia haasteita purkumateriaalien uudelleenkäytölle ja kierrätykselle on alan yritysten näkökulmasta. Tutkimus on tyypiltään tapaustutkimus, jonka aineisto koostui kenttäpäivien havainnoista, materiaalilaskelmista ja asiantuntijahaastatteluista. Tiedonkeruussa hyödynnettiin lisäksi rakennus- ja purkujätteitä käsittelevien yritysten internetsivuja ja ajankohtaisia dokumentteja. Haastateltavia yrityksiä olivat Purkupiha Oy, Gles-yhtiöt, Umacon Oy, Salpamaa Oy, Tarpaper Recycling Finland Oy, Kuusakoski Oy, EcoUp Oyj ja Remeo. Aineiston analyysissa käytettiin sisällönanalyysin menetelmiä. Tulosten perusteella tehdasrakennuksista syntyy noin 101 499 tonnia purkumateriaalia. Kartoitettuihin materiaalijakeisiin kuuluivat betoni, tiili, metalli, mineraalivilla, puu, kattohuopa eli bitumikate, lasi, muovi ja kumi, kipsi, keramiikka, asfaltti ja sähkö- ja elekroniikkalaiteromu (SER). Uudelleenkäyttöpotentiaalia on esimerkiksi ilmanvaihtolaitteilla, kuljettimilla, pumpuilla, teräksisillä rakennusosilla, liimapuutuotteilla ja tiilillä. Kaikille materiaalijakeille voidaan lähtökohtaisesti osoittaa jokin kierrätysväylä, mutta jakeisiin sisältyy joitakin materiaalityyppejä tai -laatuja, joita ei kyetä kierrättämään. Useita arvoa lisääviä kierrätysmenetelmiä on jo olemassa, mutta purkumateriaaleja hyödynnetään yhä paljon energiatuotannossa tai alhaisen arvon menetelmillä. Uudelleenkäytön ja kierrätyksen haasteissa korostuivat erityisesti taloudelliset näkökulmat sekä lainsäädännön vaikutus liiketoimintaan ja markkinoiden kehitykseen.
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Testing a novel methodology to assess carbon degradation in different coastal soft-sediment habitats (2023)Coastal habitats contribute significantly to global carbon cycling. These ecosystems store carbon into the sediment and provide a crucial ecosystem service of sequestering carbon from atmosphere. In situ carbon degradation assessment methods in coastal sediments have not been widely developed. A novel, cost-effective method for assessing degradation rates, ROMA (rapid organic matter assessment), has been developed recently, but it has not been tested yet in cool, shallow subtidal coastal areas. In this Master’s thesis, the aim is to test the ROMA methodology in shallow coastal habitats in Northern Baltic Sea. To investigate the method, following research questions were studied: (1) can carbon degradation be assessed by using the ROMA- method in the shallow coastal habitats, (2) whether carbon degradation rates differ between two sites with varying sediment characteristics, (3) how various diversity metrics and environmental context can be linked to carbon degradation rates. Results of this study show that ROMA method is feasible to assess carbon degradation rates in shallow coastal areas. There was a difference in the degradation rates between the study sites with different environmental characteristics, but the driver for the carbon degradation still seemed somewhat unclear. The methodology should be developed and trialled further, as it is promising cost-effective way to measure carbon degradation in situ.
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(2022)Mercury (Hg) is a heavy metal acknowledged as a worldwide contaminant that accumulates in organisms and biomagnifies in food webs. The organic methylmercury (MeHg) species is harmful to animals, including humans, and mainly derived from the diet. The dietary Hg consumed by fish is mostly removed through the intestine, but some of the MeHg bioaccumulates, especially in the white muscle tissue of fish. Perch (Perca fluviatilis) and roach (Rutilus rutilus) are commonly found fish species in Finland. Perch has additional im-portance as it is the national fish of Finland, a popular food fish, as well as a monitoring species used to evaluate the chemical status of lakes. Seasonal variation of Hg in muscle tissue of fish is supposedly caused by starvation in winter, which condenses Hg in the muscle, and growth dilution in summer, which refers to fast somatic growth during the growing season, which dilutes Hg in the muscle. Similar to winter, spawning has also been found to condense Hg in muscle tissue of fish due to high energy investment into gonad development. Seasonal variation of Hg and variables driving seasonal changes have been shown to differ between fish species. Seasonal variation has been studied mainly during the open-water season. However, less is known about how winter conditions under ice affect Hg levels in fish. In this MSc thesis, I asked (Q1) How total mercury (THg) content in the muscle tissue of perch and roach change annually? (Q2) How THg bioaccumulation in the muscle tissue of perch and roach change annually? (Q3) What are the factors explaining annual variation in THg content in the muscle tissue of perch and roach? The practical application of results was to discuss if annual variation should be considered in monitoring programs and human health questions. The materials used in this study were collected from Lake Pääjärvi monthly from March 2020 to March 2021. Fish were collected using gillnet series. Length, weight, sex, sexual maturity, stomach fullness, Fulton’s condition factor (K), and muscle THg were determined from each fish. The annual length-corrected THg content variation was tested using analysis of variance. The annual THg bioaccumulation variation in the relationship between muscle and fish length was tested using simple linear regression analysis, and the seasonal variation in THg bioaccumulation was tested with LOESS regression analysis. Variables affecting seasonal variation were tested with stepwise multiple linear regression analysis. THg content of perch was the highest in winter and spring and the lowest in fall, while roach showed no significant seasonal variation. THg bioaccumulation of both species was highest in winter, spring, and early summer and lowest in fall. Perch displayed more substantial seasonal variation than roach. Biological and environmental variables that explained the THg content of perch were length, ice thickness, gonadosomatic index (GSI), light, and condition factor. Variables that explained the THg content of roach were length, sex, and total phosphorus (Tot-P). This study confirmed that starvation in winter, growth dilution in summer, and spawning in spring/early summer are vital factors driving seasonal variation. Due to evident seasonal variation, monitoring month should be pre-set in current monitoring programs.
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(2024)Climate change has caused a vital need to identify the coastal ecosystems with high carbon sequestration capacity, i.e. Blue Carbon ecosystems. The ability of these ecosystems to sequester carbon is strongly influenced by the physical environment. However, previous research on Blue Carbon potential of coastal macrophyte ecosystems has mainly focused on single seagrass species whereas research on multispecies meadows along environmental gradients, such as wave exposure has been scarce. Nonetheless, exposure and depth are known to shape the functional structure of macrophyte communities. The aim of this study was to investigate if exposure and depth affect the functional structure and biomass-bound carbon stocks of macrophyte communities along an exposure gradient in an archipelago area in the western Gulf of Finland, northern Baltic Sea. Macrophyte samples were collected at two different depths (1-2 m and 3-4 m) from 20 soft-bottom sites with different exposure levels. At each site, the functional community structure was quantified by measuring four functional traits (maximum height, root depth, root-to-shoot ratio, specific leaf area), associated with the variation in plant life history strategies and in addition, the plant biomass-bound carbon was determined. The results showed that when moving from the outer to the inner archipelago, the species composition shifted from marine to limnic species, and the community functional structure was shaped by environmental conditions (i.e. wave exposure, light availability, salinity) and depended on the depth. The plant carbon stocks did not differ significantly along the exposure gradient in the shallow areas, while at increasing depth, exposed sites had the highest plant carbon stocks, which can be likely explained with the environmental factors such as light availability. To conclude, these results highlight the need for further research that investigates the connection between environmental drivers, functional traits, and plant carbon stocks to assess the Blue Carbon potential of multispecies macrophyte communities in heterogenous environments.
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(2020)Cladocerans play a key role in the aquatic ecosystem. They are abundant in lakes and are an essential part in the carbon and energy transfer of the food webs. These species are, however, prone to various environmental changes. Estimates have shown that dissolved organic carbon (DOC) concentrations in northern lakes are likely to increase in the future. This increase of DOC in lakes has multiple impacts ranging from nutrient levels to shading impacts reducing primary productions. Investigating changes in cladocerans along a DOC gradient could help us understand how these species might develop in the future in our changing climate. In this Master’s Thesis, I studied how the cladoceran body length and community structure varied between 9 lakes with dissolved organic carbon (DOC) concentration ranging from 2.4-33.5 mg l-1. For the analyses, these lakes where divided into two groups with a threshold of 12 mg l-1 or into groups of three based on their DOC concentrations. Then, the results were compared with cladoceran length data from an earlier study. Additionally, the changes in phytoplankton abundances and communities as well as the relation between DOC concentration and other environmental variables were analysed. The results showed an increase in the cladoceran body length above the DOC threshold. Moreover, the changes in body length varied between the studied genera. Both Ceriodaphnia sp. and Diaphanosoma sp. body length decreased in groups with higher DOC concentrations while Bosmina sp. were larger at high DOC concentrations. DOC concentration did not have any significant effect on the community structure of zooplankton. The studied lakes varied from their environmental condition making comparisons and general statements challenging. The results indicated that DOC concentration regulates the planktonic communities, but it is solely an imprecise predictor for changes in zooplankton communities. However, cladoceran densities seemed to benefit from increased DOC concentrations as nutrient levels also increased. Changes in cladoceran body lengths were challenging to interpret, because there are multiple factors that can have an impact both alone and combined with others.
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(2024)Cranial windows are commonly used in neuroscience for direct brain access, but they require skull removal which can lead to neuroinflammation, potentially affecting experiment outcomes. As the nature of the window varies from experiment to experiment along with parallel treatments, it is of particular interest to map the quality and extent of the resulting brain inflammation on a case-by-case basis to have a better understanding of inflammation-related confounding factors in future experiments. As the focus of our future experiments is on finding electrophysiological biomarkers of depression employing state-of-the-art in vivo electrophysiological tools through a cranial window, we would like to characterise the extent of inflammation linked to the cranial window of interest in a mouse model of depression. To achieve this, we implanted mice with a soft cranial window and afterwards, treated them with corticosterone for a month. The animals were sacrificed and astrocytic glial fibrillary acidic protein (GFAP) and microglial ionized calcium-binding adapter molecule 1 (IBA) were labelled on coronal brain sections and imaged using a confocal microscope. We quantified the percentage of GFAP+ and IBA+ pixels on brain slices as measures of neuroinflammation using an automatic global thresholding-based approach and a semi-automatised machine-learning-based approach of the QUINT workflow. Our thresholding-based analysis revealed a significant elevation in GFAP-positive pixels, indicative of astrogliosis, in mice subjected to both cranial window implantation and corticosterone treatment compared to controls. However, no significant changes in microglial reactivity were observed under similar conditions. Importantly, it appears that the cranial window alone did not evoke long-lasting brain inflammation and corticosterone only slightly affected astrocytic reactivity. And despite results using the QUINT workflow presented some confounds, our results provide important considerations for future experiments employing a combination of soft cranial window and chronic corticosterone treatment, but more research is needed to enhance the generalisability of our findings.
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(2022)More than half of the global population lives in urban areas. Urban sprawl and densification have affected urban ecosystems and the services they provide. Urban vegetation is one of the most important providers of ecosystem services. Previous studies have shown that plant functional type and age of parks/trees affect soil properties in urban environments. However, knowledge on the effects of plant roots on ecosystem services is limited. In this thesis I focused on exploring the contribution of root biomass to soil carbon and nitrogen accumulation under evergreen and deciduous trees in urban greenspaces. In addition, I explored how soil properties differ based on tree type and age of the park/tree, and how sampling distance from the tree affects root biomass and soil properties. Soil samples were taken at five distances: 1) under the canopy (midway between the trunk and the canopy edge), 2) at the canopy edge, and 3)–5) 1 m apart, starting from the canopy edge. This transect of five distances was replicated three times per tree (30 trees in total). Trees belonging to two functional types were sampled, evergreen (mostly Norway spruce, Picea abies (L.) H. Karst.) and deciduous (Linden, Tilia x europaea L.) trees. Sampling was done in young (ca. 15 years) and old (>70 years) urban parks in Lahti and Helsinki. The results show higher root biomass under young trees than old trees, and spruces had higher root biomass compared to lindens. Root biomass was positively correlated with soil organic matter, soil carbon and soil nitrogen. Sampling distance from the tree affected both root biomass and soil properties in young and old parks. Plant functional type affected soil organic matter, soil carbon, C/N ratio and acidity, but not soil nitrogen. Irrespective of tree type, soil properties varied less in old parks than in young parks between the sampling distances. Soils under old spruces had higher total carbon content compared to young spruces, whereas for lindens, tree age affected soil carbon less on. Total nitrogen content was higher in old parks than in young parks for both tree types. My study provides new information about how park tree roots affect urban park soil carbon and nitrogen accumulation. There are no previous studies on how far this root effect extends, and my study fills this knowledge gap. My results show that tree roots are an important factor in urban park carbon stocks. I also showed that age of the park/tree has an evident effect on urban soil properties. In the light of my research findings, it seems that a significant portion of ecosystem services provided by urban vegetation is produced underground.
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(2019)Corporations’ desire to act in a responsible way as well as the amount of sustainability guidelines has increased during the past decades. Responsible Care (RC) program is an international sustainable development guideline practiced in chemical industry. The program focuses on sustainable use of natural resources, safety and sustainability of production and products, well-being of work community and reduction of waste and emissions. This study seeks to examine the correspondence of contents between national Responsible Care (RC) program in Finland and sustainability framework guidelines known worldwide. The aim of the study is to examine how corporations in chemical industry who follow the national RC program can meet the goals of sustainability framework guidelines, what are the main differences between the national RC program and other sustainability guidelines, and how the national RC program should be improved. The research methods include the content analysis and in-depth interview for corporations. In this research, the sustainability framework is built and the involved guidelines are specified. The national RC program is reflected on the sustainability framework guidelines through content analysis. A model for comparative content analysis is developed to compare the contents of sustainability guidelines by the means of qualitative data visualization through radar charts. The corporate in-depth interviews are applied with a view to obtain complete and comprehensive responses. This study demonstrates that the national RC program highly corresponds to sustainability framework guidelines in terms of environmental responsibility and safety, while the RC program less highlights the dimensions of social and economic responsibility. Based on the main differences, the possible targets for improvement in the national RC program are suggested to enhance consideration of economic and social aspects in the program. From the in-depth interviews, corporations recognize the national RC program to be a useful tool to implement and develop corporation’s sustainability work, yet there is a need to better correspondence with sustainability framework guidelines and to be more user-friendly in practice.
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(2021)Forests have become one of the key themes when it comes to sustainability and have been subject to many demands and pressures from various stakeholders in recent years. In particular, the responsible use of forests has surfaced in discussions during the past 20 years. As the world and overall atmosphere is becoming more favorable to sustainability, companies are required to adapt to a changed society. The forest industry has a significant impact on Finland’s sustainable development and economy. In the forest industry corporate responsibility work has developed as demands from society have grown and the work has become more holistic over time as knowledge on the matter has increased. Pressures on companies' environmental work have come from outside companies from society, as well as from internal actors within companies. One well established forest industry company in Finland is Metsä Group, which has long been profiled as an environmentally responsible company. Therefore, corporate responsibility work and its development in Metsä Group has been selected as my research topic. In this thesis, I examine how environmental responsibility work has changed from the point of view of sustainability professionals in Metsä Group during the years 2000-2020. As research material, I use interviews with Metsä Group's sustainability professionals, as well as responsibility and annual reports from 2000-2020. For the interviews, I selected former and current Metsä Group employees who have worked in the company, either the whole duration or partly, during the years 2000-2020. I have analyzed the materials using content analysis as a method. The interviews revealed that, in general, employees felt that, compared to the early 2000s, in 2020 Metsä Group took more and more holistic action for its environmental responsibility. In general, it was seen that the most significant factors influencing corporate responsibility were megatrends such as climate change and biodiversity loss, as well as a general change in societal perceptions related to corporate responsibility. Leaders’ commitment and attitude towards environmental responsibility, as well as customer requirements, were also perceived as significant factors in promoting responsibility work. It was generally felt that if customers or management saw the matter as important it was invested in. All in all, the environmental corporate responsibility of Metsä Group had steadily improved during 2000-2020. Overall, the interviewees felt that environmental responsibility has been incorporated into Metsä Group's strategy, and that corporate responsibility work has become more holistic and professionalized.
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(2021)The way environmental issues are discursively constructed matters for how they are understood and what possibilities there are to solve them. This makes it relevant to investigate discourses around environmental issues and their proposed solutions. One such solution is ecological compensation, which has been widely implemented as a way to avoid environmental degradation and achieve no net loss of biodiversity. Compensation is also a contested mechanism, however, which has been shaped by the interplay of various discourses with diverging understandings of nature conservation. In this study, I investigate how ecological compensation is constructed by experts in Finland. Using the concept of storylines (Hajer 1995) I analyse 9 interviews conducted with experts involved in the discussion around ecological compensation, which is currently being implemented into Finnish legislation. Three storylines are identified which construct ecological compensation either as 1) a way to enable private actors to take environmental responsibility, 2) additional legislation to fill a “gap” in current conservation practices, or 3) a possibility to modify the relationship with nature by fostering local deliberations. This shows diverging understandings of ecological compensation among the experts and contestation over the way it should be implemented. What is at stake in the discussion are questions of how nature conservation should be understood, which makes ecological compensation pivotal for reconfiguring the field of nature conservation by shifting understandings of the roles and responsibilities involved. At the same time, consensus exists about the need to implement ecological compensation, which the experts all agree is the only possibility to stop biodiversity loss in Finland. This is traced to the interpretative flexibility of the ecological compensation concept which accommodates conflicting understandings and enables the experts to agree about the need for ecological compensation while contesting the “details” of how the implementation should take place. In that way, the implementation is supported despite contestation, and the discussion is focused on how – rather than whether – ecological compensation should be implemented.
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(2021)Microbial diversity can be found everywhere around us. The diversity is however declining globally and the diversity loss is most visible in highly urbanized areas. The lack of microbial biodiversity has been linked to increased risk of certain im-mune mediated diseases most prevalent within urban population. Understanding how diversity differs between urban and rural areas can help us to figure out mechanisms behind biodiversity loss and higher frequency of immune-mediated dis-eases and develop prevention methods for the latter. The aim of the thesis is to study how bacterial communities differ between urban and rural areas using indicator species as proxy. The aim is also to find out if the results support the biodiversity hypothesis. The results of the thesis found out significant differences in diversity indexes between bacterial communities in urban and rural areas, which supports the biodiversity hypothesis. The study also found differences in Proteobacteria diversity index-es, which have been linked to some immune mediated diseases in previous studies.
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(2021)This thesis explores the drivers and barrier to greening in the Finnish music festival scene. The term greening originates in literature on sustainable business and refers to the process of a company achieving greater sustainability through investments, managerial and organisational decisions and implementing policies and processes. The concept of greening is applied to music festivals, a type of event, that cause significant negative environmental impacts. Sustainable event management attempts to mitigate negative environmental impacts and to cause positive impacts for instance through environmental education and inspiring behaviour change. As a theoretical framework, this thesis uses drivers and barriers impacting the greening of music festivals identified in literature. The drivers (organisational and personal values, competitive advantage, consumer demand and the desire to educate) and barriers (lack of finance or support from stakeholders, lack of control over venues, lack of control over patron behaviour, lack of time, lack of sustainable supplies and suppliers), networking in the festival scene and the use of external environmental audits form the basis for a qualitative content analysis. The findings based on interview data from five Finnish music festival managers and a representative from an environmental auditing service suggests that the most significant drivers are value-based and the motivation for greening stems from personal pro-environmental values and the desire to inform and educate audiences. The barriers to overcome are external, related to stakeholders, infrastructure and the supply chain as well as unsustainable attendee behaviour. Additionally, there is among festival managers some uncertainty regarding best practices. A need for increased support from stakeholders and for accessible information highlights the importance of networking. External auditing services should offer flexible and contextual tools and a more inspirational tone. In conclusion, sustainability is seen by the Finnish music festival scene as a key issue and one of increasing priority in the future.
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(2020)Iron-manganese (FeMn) concretions are found on soft sediment bottoms both in the deep sea and coastal sea areas, formed as a result of a combination of biogeochemical and microbial processes. It has been estimated that concretions occur at least in 11 % of the Finnish marine areas. Concretions form hard substrates on predominantly soft seafloors, and they are therefore suggested to increase geodiversity and habitat complexity of the seafloor. This has been found to correlate with biodiversity of the benthic fauna. Despite their widespread occurrence in the northern Baltic Sea, the ecological importance of FeMn concretions has been left unaddressed. In the recent assessment of threatened habitat types in Finland, concretion fields were classified as a data deficient habitat type. The aim of this study is to examine the role of FeMn concretions as habitats in the Baltic Sea ecosystem. Benthic biodiversity was investigated utilizing two approaches; the abundance of mobile fauna and sessile macrofauna were studied with point-dives. The data was compared to pre-existing data from similar soft bottoms where there are no observations of concretions, collected in the Finnish Inventory Programme for the Underwater Marine Environment (VELMU). Samples for sediment in-fauna were taken with a Van Veen Grab Sampler, and additional data was gathered also from Environmental Information System HERTTA (administered by Environmental Administration). The shape and quantity of concretions appear to affect the abundance of sediment in-fauna. Similarities to the invertebrate composition of soft sediment habitats depends of the soft sediment availability in the habitat, which is dependent on concretion shape and quantity. Crusts seem to affect the faunal composition more than spheroidal and discoidal concretions, as they offer the most complex habitats, significantly different from bare seafloors. Based on this study, the concretion fields should not necessarily be considered as just one habitat type, since the faunal composition appears to differ according to the shape of the concretions.
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(2013)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.
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(2019)GRACILE (Growth Retardation, Aminoaciduria, Cholestasis, Iron Overload, Lactic Acidosis, and Early death) syndrome (Fellman disease, MIM603358) is a mitochondrial disorder that belongs to the Finnish disease heritage and follows an autosomal recessive inheritance pattern. It is a lethal neonatal disease and the affected infants usually survive only a couple of days, but in some cases up to four months. The disease is very rare affecting about 1 in 47,000 infants in Finland. GRACILE syndrome is caused by a homozygous Finnish founder mutation (c.A232G) in the BCS1L gene, which encodes an assembly factor for the mitochondrial respiratory chain complex III. The missense mutation (c.A232G) causes an amino acid change (p.S78G) in the BCS1L protein. Alternative oxidase (AOX) is a terminal oxidase that is not naturally present in mammals. It enables the respiratory chain electron flow to bypass complexes III and IV. The AOX pathway works parallel with the respiratory chain and gets activated under stress conditions in plants and lower animals. In mitochondrial diseases with a complex III deficiency, such as GRACILE syndrome, AOX expression could alleviate the symptoms caused by the complex III dysfunction. The aim of this study was to investigate the effects of AOX expression on early-onset manifestations of the disease in the Bcs1lc.A232G mouse model of GRACILE syndrome. The mice used in this study have a genetic background with a short survival to P35-40. The respiratory chain function in freshly isolated mitochondria from the liver and kidney was studied, as well as complex III activity, mitochondrial mass and liver and kidney histology. The findings of this study suggest that AOX has a strong beneficial effect on both liver and kidney histology and it is able to restore the glycogen stores to some extent, thus alleviating the glycogen depletion seen in the mice. The Bcs1lc.A232G mice also had an improved body weight in the presence of AOX, suggesting a less severe energy deficiency due to the activity of the AOX transgene. CI- and CII-linked respiration was also robustly improved in the liver. Overall, the condition of the Bcs1lc.A232G mice was improved by the presence of the AOX transgene compared to the Bcs1lc.A232G mice not expressing AOX. These results are highly encouraging for further studies on the rescue effects that AOX seems to have on this disease model.
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(2022)Light pollution, or artificial light at night, is a globally increasing environmental problem that threatens especially nocturnal organisms dependent on darkness. Modern lighting technology offers opportunities for mitigation of the ecological impacts of light pollution, but effective implementation requires better understanding of how different artificial light qualities, such as light spectrum, influence its effects on wildlife. The common glow-worm, Lampyris noctiluca, is an example of a species believed to be suffering from light pollution. Artificial light has been found to interfere with glow-worm reproduction by decreasing the success of females in attracting males with their glow. In this study, I investigated how the color (spectrum) of artificial light affects the attraction of male glow-worms towards a female mimicking stimulus, in order to find out whether certain colors of artificial light are less detrimental to glow-worm reproduction than others. I used dummy female traps to capture male glow-worms in the field and compared the catch success of traps in different treatments: illuminated from above with blue, white, yellow or red artificial light, or left unilluminated as a control. I also conducted a laboratory experiment where male glow-worms were given two choices. One of the choices was an unilluminated dummy female, and the other was either a dummy female illuminated with yellow or red light, or a red light illuminated area with no dummy female. Traps illuminated with short wavelength artificial light (blue and white) caught significantly fewer males than unilluminated traps or traps illuminated with long wavelength artificial light (yellow and red). There was no significant difference in the number of males caught between unilluminated traps and traps illuminated with long wavelength artificial light. In the laboratory, males significantly preferred an unilluminated dummy female over a dummy female illuminated with yellow light. However, the males chose a red light illuminated dummy female or area more often than an unilluminated dummy female, although this difference in preference was not significant. The results show that mate attraction in the glow-worm is influenced by artificial light color, with short wavelength artificial light decreasing the mate attraction success of female glow-worms more than long wavelength artificial light. This could point to yellow-tinted artificial lighting presenting an ecologically friendly alternative to cool white lighting. However, the specifics of how long wavelength artificial light affects male glow-worm perception of female attractiveness are still unclear. Furthermore, male glow-worms show signs of attraction towards long wavelength artificial light, which could form an evolutionary trap for them. The impacts of artificial light spectrum on organisms are thus not straightforward, but can vary depending on both species and situation.
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(2020)Bipotential gonads are precursor structures for testes and ovaries. Steroidogenic factor-1 (SF1) is one of the most important transcription factors in an embryo needed for the development and maintenance of bipotential gonads. If SF1 is not expressed, bipotential gonads fail to develop, and genitalia and kidneys are not formed. Later, SF1 expression persists high in testes, where it supports Sertoli and Leydig cell formation and development. If SF1 is not expressed enough in males, the bipotential gonads differentiate into ovaries. The factors activating and regulating SF1 are not currently fully known. By getting more knowledge of how SF1 is controlled, regulatory mechanisms behind normal fetal development of gonads and disorders of sex development (DSD) can be understood better. The aims of this thesis were to study whether growth factors, that naturally regulate differentiation of developing gonads, promote differentiation of human induced pluripotent stem cells (hiPSC) into Sertoli-like cells (SLCs) and whether SF1 expression is induced by the addition of these growth factors. For conducting the study, we used hiPSCs, which have an SF1 activation domain cassette previously introduced to the cells by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) (CRISPR/Cas9) method. SF1 could be activated by adding doxycycline (DOX) and trimethoprim (TMP). These hiPSCs were differentiated into intermediate mesoderm (IM) on the first four days according to the protocol published earlier by the group. After this, the differentiation to SLCs was guided by adding growth factors to the culture medium. Basic fibroblast growth factor (bFGF), fibroblast growth factor 9 (FGF9) and prostaglandin-2 (PGD2) were tested separately and in a combined cocktail also including follicle stimulating (FSH) and glial cell-derived neurotrophic factor (GDNF). In a control condition, cells were differentiated without additional growth factors. In all tested conditions, cells first differentiated into IM were further differentiated either in the presence or absence of DOX and TMP for 8 days. The differentiation medias were changed to the cells every day and lysis samples for quantitative PCR (qRT-PCR) were taken every other day. The relative gene expression levels of bipotential gonad, testis and steroidogenic gene markers from each condition were monitored with qRT-PCR and compared to the levels of the undifferentiated hiPSCs. Immunocytochemistry was performed to see the changes in protein production. Against our hypothesis and the previous studies by others, none of the tested growth factors induced the cells to differentiate into SLCs. However, SF1 expression was triggered by chemical induction with DOX and TMP. Also, the expression levels of bipotential gonadal and testicular gene markers increased in control conditions with/without chemical induction. PGD2 conditions were the only ones to resemble the gene expression and morphology of control conditions while the others differed. These results indicated that the addition of bFGF, FGF9, FSH and GDNF did not improve the differentiation of iPSCs into SLCs and in fact, bFGF and FGF9 hindered their differentiation into SLCs. As a future perspective the optimal concentrations for each growth factor and the duration of growth factor supplementation ought to be tested to refine the protocol.
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(2021)Lake ecosystems are shaped by water chemistry processes that affect the lake environment and the species communities within. Changes in the water chemistry thus have far-reaching consequences. Water colour is one variable that affects water chemistry and stems from humic substances in the water. Dark water reduces light availability and also affects nutrient and oxygen availability. A trend of brownification of freshwater systems has been observed in recent years and it is expected to influence species community’s diversity and composition. The aim of this thesis was to study whether brownification is an ongoing issue in the study lakes and whether it has had a negative effect on phytoplankton diversity and resulted in shifts in the phytoplankton composition. A data set including about a 100 lakes in Finland with measurements from 1965 up until now served as the study system which was analysed with statistical methods. The results indicated a brownification trend in the past decades. The brownification so far had a positive impact on species richness but a negative impact on beta diversity. Brownification also affected species composition. Flagellates and autotrophic species increased in darker waters but mixotrophic species that are known to dominate in dark water colour, did not show a clear increase with water colour. Other hydrological variables than water colour could have had a bigger impact on the phytoplankton community than water colour but future monitoring of the phytoplankton community is recommended to see if water colour will have a negative impact on species diversity in the future.
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(2019)Understanding the link between the gut microbiota, diet and the enteric nervous system is of significant importance in the prevention of gastrointestinal disorders. The aim of the study was to answer two questions: Firstly, is butyrate able to stimulate the luminal release of serotonin? Secondly, in which parts of the gastrointestinal tract does this possibly occur? These questions are of interest, due to the importance of the serotonergic signalling in the enteric nervous system. We created a luminal perfusion system to investigate the effect of butyrate in the gastrointestinal tract of male Wistar rats (500-550g). We isolated the stomach and 4 cm long segments of the duodenum, jejunum and colon. To our knowledge this form of physiological ex vivo studies investigating the entire gastrointestinal tract have not been done previously. The isolated stomach and the isolated intestinal segments were luminally perfused with 100 mM butyrate for 10 min respectively 45 min. The tissues were homogenized after the luminal perfusion. Serotonin and its main metabolite 5-hydroxyindoleacetic acid (5-HIAA) were assayed using commercial ELISA kits. Our results showed that butyrate significantly stimulates the release of 5-HIAA in the stomach, duodenum, jejunum and colon. Butyrate seems also to have a positive trend-effect on the release of serotonin itself in the stomach, duodenum, jejunum and colon. Although, there is a future potential for preventing gastrointestinal disorders with the help of diet and gut microbiota, the possible clinical significance of our results should be considered carefully.
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(2019)Epithelial cells form a barrier between the tissue and the external environment. Epithelial morphogenesis refers to the shaping of epithelial layers and is a key step in the development of organisms. The actin cytoskeleton provides the cell its form and during epithelial morphogenesis, produces force to shape the cells. To achieve this, the actin cytoskeleton is organized into protrusive and contractile networks. In a living cell, these actin networks are dynamic, as the filaments are constantly undergoing assembly and disassembly. Actin-binding proteins regulate the turnover of actin filaments, but in epithelial morphogenesis, the regulatory role of most of these proteins is still relatively unknown. In all multicellular organisms, actin disassembly is controlled by ADF/cofilin. ADF/cofilin activity is furthermore enhanced by other actin-binding proteins, one of which is cyclase-associated protein (CAP). CAP promotes actin turnover by accelerating ADF/cofilin mediated actin disassembly and in recycling actin monomers to sites of actin polymerization. Unlike ADF/cofilin that regulates actin disassembly throughout the whole cell, CAP could be subject to more specific spatial regulation, as loss of CAP leads to F-actin accumulation on the apical side of epithelial cells. However, the role of CAP in morphogenetic cell rearrangements remains poorly known. In addition, the in vivo role of the biochemical functions of CAP has not been elucidated. The aim of this master’s thesis is to describe the role of CAP in regulating the actin cytoskeleton in the follicular epithelium of the fruit fly Drosophila melanogaster. For this purpose, chimeric mutant flies with homozygous CAP loss of function mutation were generated. Subsequently, the effect of the CAP loss of function was observed in follicle cell populations undergoing morphogenetic changes. In addition, CAP loss of function was rescued with different transgenes producing mutant CAP proteins to identify the protein domains of CAP with in vivo significance. In addition, a Drosophila CAP specific antibody was purified to be used in immunostaining. The ovaries were imaged using confocal microscopy. In this thesis, it is shown that CAP loss of function caused accumulation of filamentous actin in all observed follicular cell populations. Surprisingly, the actin turnover was rescued by all of the used CAP rescue transgenes, but the mutant transgenes exhibited phenotypes resembling the CAP loss of function in other epithelial tissues. Moreover, CAP loss of function caused defects in the follicle cell movement and cell spreading. The loss of function also caused expression changes in other actin-binding proteins. The findings of these thesis support the current knowledge of CAP importance for functional actin turnover in the follicle cells, even though the protein domain necessary for in vivo function could not be deciphered. Moreover, this project provides indication that CAP has an indispensable role in dynamic morphogenetic processes in the epithelium. Together with other actin-binding proteins, CAP could regulate epithelial actin turnover in spatially directed manner, providing force for epithelial cell adhesions or protrusions.
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