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Lack of Ectodysplasin (EDA), caused by a mutated Eda gene, leads to a syndrome called hypohidrotic ectodermal dysplasia (XLHED) with defects in ectodermal organs such as teeth, hair and sweat glands. The molar teeth of Eda knock out (Eda KO) mice are absolutely and relatively smaller and have fewer cusps than the wild type (WT) molar teeth. In the absence of the EDA protein, the receptor of the EDA signalling pathway (EDAR) remains functional, and therefore EDA-protein therapy can rescue the development of ectodermal organs. The aim of this study was to determine EDA sensitivity windows and to describe the Edar expression pattern in developing mouse lower molars. Eda KO mouse skulls treated with EDA for 24 hours at different stages of development were imaged using x-ray microtomography. The response was studied by analysing the cusp patterns and size proportions of lower molars. In situ hybridisation was used to detect the Edar expression in the developing Eda KO and WT molars at different stages. The results show that molars are sensitive to EDA at the early stages of crown patterning, at the time when Edar is expressed in the primary enamel knot and the secondary enamel knots. The Edar expression pattern suggests that EDA signalling regulates molar size and cusp development through these signalling centres. EDA-treatment during a sensitivity window enhances the growth of the EDA sensitive molar, thereby breaking the previously reported inhibitory cascade –rule. The results of this study provide information for optimising the EDA therapy for XLHED patients.

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.

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.

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.

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.

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.

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.

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.

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.

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.