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  • Lehtinen, Oskari Jouko (2022)
    Lifespan is a key fitness trait, together with fecundity, dispersal, and growth. In addition to environmental factors shaping variation in lifespan, it is also influenced by genetic components. Based on theory, genetic variation in lifespan is expected to be reduced due to its high relevance to fitness. However, due to trade-offs between different life-history traits and the variable or unstable environmental conditions organisms face in nature, life-history traits are also expected to sustain higher genetic variation. From studies in model organisms, such as the fruit fly and the roundworm, researchers have uncovered key insights into the genetic basis of lifespan. Some genes have been shown to contribute more to lifespan than others and different species seem to share homologous genes influencing lifespan that have been conserved. Many of these genes relate to the insulin receptors and insulin signaling processes. The allelic variation and over- or under-expression of these genes have been shown to be associated with changes in lifespan. However, regardless of our accumulating knowledge of these genes in impacting lifespan under laboratory conditions, we have little understanding of the role of these genes impacting variation in lifespan under more natural conditions. In general, assessment of genes affecting variation in lifespan in natural populations is rare, even under circumstances where we know that the lifespan has a heritable component. The Glanville fritillary (Melitaea cinxia) is a butterfly that inhabits most of Europe. It is used as a model species in ecology and evolution in relation to metapopulation dynamics and spatially structured habitats. It has been studied extensively both under experimental conditions and via observational studies in the field. The Glanville fritillary butterfly works as a good model organism for assessments of genetic components of life-history variation, as vast amounts of genomic and ecological data are already available. In this thesis, I aim to shed light on the genetic background of lifespan by using the Glanville fritillary as a model organism. More specifically, I will test the association of some well-known lifespan-related candidate genes with a phenotypic variation on the butterfly’s adult lifespan based on previously obtained experimental data on individuals collected from the natural metapopulation during the larval stage.
  • Häkkänen, Iina (2022)
    Colorectal cancer (CRC) is one of the most common types of cancers, encompassing approximately 10 % of all cancer cases worldwide. Regulation of cell proliferation and cell fate decisions is crucial for maintaining cellular homeostasis and preventing CRC initiation, a process in which the Wingless (Wnt)/β-catenin signalling pathway is known to play an important role. For instance, somatic mutations occurring in the Apc gene lead to aberrant activation of the Wnt/β-catenin pathway, which further leads to the accumulation of β-catenin into the nucleus where the TCF/LEF transcription factors, including TCF1, TCF3, TCF4, and LEF1, bind β-catenin to activate downstream Wnt target genes and promote CRC development. TCF1 is encoded by the gene Tcf7 that can be alternatively spliced to produce long (p45) and short (p33) isoforms whose function in CRC development has remained poorly understood. Previously, deletion of Tcf7 has been found to increase intestinal adenoma formation in mice with one mutated Apc allele (ApcMin/+), which are predisposed to development of multiple intestinal adenomas. To study how heterozygous deletion of the p45 isoforms affects intestinal adenoma formation and the cellular transcriptome, we have studied ApcMin/+ mice, which have a heterozygous mutation of Tcf7 gene encoding only the p33 isoform (AmTp45∆/+). In our study, we used immunohistochemistry and RT-qPCR together with a single-cell RNA sequencing (scRNA-seq) analysis. Heterozygous deletion of the p45 isoforms in the ApcMin/+ mice dramatically increased the numbers of intestinal tumours, spleen size and its white pulp areas but it had no effect on cell proliferation or expression of the Wnt-target gene Prox1 in intestinal adenomas. In addition, ApcMin/+ mice with both heterozygous p45 and Lef1 deletions developed significantly more intestinal tumours. Without the Apc mutation, neither of these mouse models developed intestinal adenomas or spleen abnormalities. RT-qPCR analysis showed decreased expression of Tcf7 in the small intestine of the AmTp45∆/+ mice. scRNA-seq analysis revealed that the AmTp45∆/+ mice downregulated various Wnt antagonists and stem cell markers and upregulated several genes that function in different metabolic pathways. Overall, these results support the concept that Tcf7 functions in synergy with Apc to repress intestinal malignancy. Our results establish a basis for comparison of the relative importance and specific functions of the TCF/LEF1 family members in CRC development.
  • Juurinen, Valtteri (2022)
    Opinnäytetyössä tutkittiin olosuhteiden muutosten vaikutusta torjunta-ainepitosuuksiin pilot-mittakaavan sedimenttipylväissä ja suodatinpylväissä. Pilot-mittakaavan pylväissä verrattiin ilmastuksen ja veden virtauksen muutosten vaikutusta pitoisuuksiin. Suodatinpylväissä tarkasteltavina tekijöinä oli orgaanisen aineen ja nollaraudan vaikutus torjunta-ainepitoisuuksiin. Tutkittavina torjunta-aineina olivat atratsiini, simatsiini, heksatsinoni ja diklobeniili, sekä hajoamistuotteet DIA, DEA, DEDIA ja BAM. Kyseisiä torjunta-aineita esiintyy pohjavesissä useissa eri Euroopan maissa mukaan lukien Suomi, vaikka niiden käyttö on lopetettu ja kielletty EU:n alueella useita vuosia sitten. Pylväistä analysoidut ulostulovedet valmisteltiin kaasukromatografia-massaspektrometria (GC-MS) mittausta varten kiinteäfaasiuutolla. Suodatinpylväiden torjunta-aineiden puhdistuskapasiteetti vaihteli testikertojen välillä ja yhdisteet käyttäytyivät eri tavalla suhteessa toisiinsa. Ensimmäisen kuukauden jälkeen talousveden raja-arvo 0,10 µg/l ylittyi heksatsinonin osalta. Toisen kuukauden jälkeen heksatsinonin pitoisuus ylitti jälleen talousveden raja-arvon, niin kuin myös BAM:n. Sitten viimeisellä testikerralla kohonneita yli 0,1 µg/l pitoisuuksia oli atratsiinilla ja heksatsinonilla. BAM:n ja heksatsinonin kulkeutuminen oli odotettavissa yhdisteiden ominaisuuksien perusteella ja niiden hajoaminen on hidasta verrattuna muihin yhdisteisiin. Puolestaan atratsiinin kohonneet pitoisuudet voidaan selittää maaperän kiintoaineksen liikkumisella suodatinpylväästä torjunta-aineiden kanssa. Pelkän hiekan vaikutus suodatinpylväissä aliarvioitiin, mikä vaikutti erityisesti BAM:n ja heksatsinonin pitoisuuksiin.
  • Malmberg, Jenny (2022)
    Many maternally inherited bacterial infections in insect species can have negative or positive effects on their hosts. One of the diverse phenotypes these bacteria can induce in their hosts is the selective death of the male offspring at early development stages. Male-killing (MK) symbiotic bacteria have been reported in diverse insect species, and these symbionts have been shown to play important roles in shaping the ecology and evolution of diverse host species. One such species is the African Monarch butterfly: Danaus chrysippus, the target species of my study. There are four subspecies of D. chrysippus, which are geographically loosely isolated in different parts of Africa. However, they do interbreed in a hybrid zone located in central Africa. The MK phenotype in D. chrysippus is caused by a Spiroplasma bacterium, which is highly prevalent in the host hybrid zone, where the MK phenotype is so strong that females can only reproduce thanks to a few males that migrate from the surrounding subspecies. Other studies have found a correlation between the size of the female (wingspan) and infection rate. In my thesis the main objective is to study parts of the internal female structures, aiming to investigate if the size of the female reproductive organs correlates with infection as well. My hypothesis is that the female reproductive organs are smaller in highly infected areas because the rare males produce small and resource-depleted spermatophores. This study considered if D. chrysippus females collected from different populations (with different infection rates and sex-ratios) showed a difference in the size of their reproductive organs (corpus bursae and signa). Some females were also dissected to count the amount of spermatophores, and to measure their size. My study includes photographs of these particular organs (corpus bursae and signum) because those have not been published before. The results showed that (A) Danaus chrysippus has two signa, one on the ventral- and one on the dorsal side of the corpus bursa, and they are covered with spike-like structures; (B) spermatophores varied in size between females, but that population, female infection status and population sex-ratio did not significantly affect spermatophore count nor spermatophore size, and (C) in Rwanda, where the sex-ratio is slightly female-biased, the signa covered a significantly smaller portion of the females’ corpus bursa than observed in females from other populations showing either no or a strong female sex-ratio bias.
  • Mäki, Ilona (2022)
    Biochar is a porous, carbon-rich material, made from organic material by pyrolysis in low oxygen conditions, and it can be used to sequester carbon into the soil. This review aspires to give an overview of the economic dimensions of using biochar in Finnish (Boreal and sub-boreal) forests. A literature review was conducted to collect and summarize the information about studies and applications elsewhere, and how we could possibly apply them into Finnish forest ecosystems. This thesis is done as part of Helsus Co-Creation Lab -project, where our group was tasked with looking into how biochar could enhance biodiversity in soil and accelerate transformation to low carbon economy. From this larger topic, this paper is looking into the economic side, and whether it is economically viable to use biochar to enhance and uphold biodiversity. This is evaluated by reviewing and categorizing 164 papers and conducting a literature review. My conclusions are that the current biochar applications show lower economic efficiency than other carbon dioxide abatement technologies. The stability of biochar in soil is a key factor, as the half-lives of biochars may not be as long as commonly suggested. Furthermore, competition for biomass resource use can restrict the availability of feedstock, and make it more expensive. Subsidies for biochar application are required if biochar is to be- come a significant part of the national or global climate mitigation policy. The results in different articles are quite variable and there is currently no standard approach to them. There is a need for specific research on what kind of biochar benefits what soil and vegetation, which is expensive. A primary goal is to incorporate a consistent and standardized testing or analysis method for biochar stability into the certification programs run and administered by the International and the European Biochar Initiatives. In the foreseeable future, biochar by itself is unlikely to play a significant role in climate mitigation strategies. Biochar might be just one of several alternatives in a bundle strategy to re- duce carbon emissions. However, its potential use must still be researched more.
  • Gómez Sánchez, Celia (2022)
    Kv7.1 is a potassium ion channel comprised of the KCNQ1 protein, which can coassemble with distinct β-subunits modulating the channel functions in different tissues. In 2017, Raivio’s group (from the University of Helsinki) found two missense mutations in the KCNQ1 gene, p.(Arg116Leu) and p.(Pro369Leu), responsible for causing pituitary hormone deficiency and maternally inherited gingival fibromatosis. The facial features and bone structure pointed to a cranial neural crest (CNC)-derived phenotype caused by an alteration in the potassium channel balance, given that these cells form the bone and cartilage of the cranial zone. To understand the implication of the CNC in the KCNQ1 syndrome, I attempted to replicate the CNC differentiation protocol of Suga and Furue (2019) with the aim of obtaining cranial neural crest cells (CNCCs). This would enable future generation of a KCNQ1-related disease model. The differentiation process was carried out thrice, and two BMP4 concentrations (10 and 100 ng/ml) were assayed. The differentiated cells exhibited a CNC-like morphology as well as upregulation of the marker genes (TFAP2A, SOX10, DLX1, MSX1, and DLX2) associated to this cell lineage. However, the gene expression was low according to the qRT-PCR Ct values, which were in most cases higher than 30. Additionally, no differences were found between the two BMP4 treatments. Furthermore, the cells did not express KCNQ1, and thus the impact of the two KCNQ1 mutations was not investigated under this protocol. In conclusion, the protocol had a low efficiency in the generation of CNCCs that was not improved by increasing the BMP4 concentration. Further optimization of the protocol, such as the BMP4 concentration or the cell density of the culture, will be needed to improve its efficiency and obtain an adequate disease model.
  • Laiho, Helene (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.
  • Höglund, Eiko (2022)
    Kiihtyvän ilmastonmuutoksen aikana on entistä tärkeämpää löytää tapoja vähentää päästöjä ja sitoa hiiltä. Biohiilen käyttö on yksi keino ilmastonmuutoksen hillitsemiseen, ja sillä on potentiaalia parantaa maatalouden satoja. Ennen kuin biohiilen käyttö voi yleistyä, sen mahdolliset ulkoisvaikutukset, kuten vaikutukset maaperän eliöstöön, on kuitenkin ensin selvitettävä. Tässä opinnäytetyössä tutkittiin biohiilen käytön vaikutuksia mikrobien suhteelliseen runsauteen, kastematoyhteisöihin ja mikrobibiomassaan. Vain lauhkean ja boreaalisen vyöhykkeen kenttätutkimukset olivat osana tutkimusta. Biohiilen vaikutukset mikrobiryhmien suhteelliseen määrään selvitettiin kirjallisuuskatsauksella. Kirjallisuuskatsaus tehtiin myös selvittäessä biohiilen vaikutuksia kastematoihin. Biohiilen vaikutukset mikrobibiomassaan selvitettiin meta-analyysillä. Meta-analyysissä käytetyt tutkimukset luokiteltiin muuttujien, kuten biohiilen raaka-aineen, pyrolyysilämpötilan, maaperän pH:n, SOC:n, maaperän rakenteen ja biohiilen levitysmäärän perusteella. Tätä kautta voitiin selvittää, voisiko jokin näistä muuttujista selittää meta-analyysin tulokset. Mikrobien suhteellisen runsauden havaittiin muuttuvan biohiilen lisäyksen myötä, mutta reagoivat organismiryhmät vaihtelivat suuresti ja vaikutus yleensä haihtui ajan myötä. Biohiilen lisääminen ei vaikuttanut kastematoihin merkittävästi. Meta-analyysien tulokset viittaavat siihen, että biohiilellä ei myöskään ole merkittävää vaikutusta mikrobien kokonaisbiomassaan. Eri muuttujilla tehdyt meta-analyysit viittaavat siihen, että biohiilen lisäyksellä on positiivisin vaikutus mikrobien biomassaan happamissa maaperissä, joissa on karkea rakenne ja korkea SOC-pitoisuus, kun biohiiltä tuotetaan 500 °C–700 °C:ssa ja levitetään määrinä, jotka ovat suurempia tai yhtä suuri kuin 30 t ha-1. Biohiilen raaka-aineella ei havaittu olevan merkittävää vaikutusta. Yhteenvetona voidaan todeta, että mikrobi- ja kastematoyhteisöt pysyvät yleensä vakaina biohiiltä käytettäessä. Tämä mahdollistaisi biohiilen käytön mm. hiilen sitomiseen ja maaperän hedelmällisyyden lisäämiseen maaperän eliöstöä vahingoittamatta. Lisätutkimusta kaivataan kuitenkin erityisesti boreaalisilla alueilla sekä biohiilen ja pääviljelykasvin mahdollisista vuorovaikutuksista. Tutkia kannattaisi myös mahdollisuuksia käyttää biohiiltä yhdessä muiden orgaanisten käsittelyjen, kuten lannan tai kompostin kanssa biologisen monimuotoisuuden ja sadon parantamiseksi.
  • Repetti, Sonja I. (2022)
    My master’s thesis aims to determine the effect of salinity on phytoplankton traits related to nutrient acquisition, and particularly how this interacts with resource availability. Salinity is an important driver structuring phytoplankton communities in the Baltic Sea. Salinity can also influence nutrient uptake by increasing metabolic rates required for osmotic adjustment. Thus, interaction between salinity and nutrient availability is expected to change community structure by altering phytoplankton traits determining resource competition. This is a particularly relevant area of study for the Baltic Sea due to predicted future freshening of the sea’s upper layer. We performed a microcosm experiment using artificial communities of 10 diverse phytoplankton species grown under different combinations of salinity (0, 5, 12 and 24), Nitrogen to Phosphorus molar ratio (N:P ratio = 2, 10, 16 and 80) and light (10 and 130 µmol photon m-2 s-1) conditions. A three-way interaction among these environmental parameters influenced phytoplankton traits associated with resource competition, as well as the presence and proportions of phytoplankton taxa. Light limitation inhibited community growth under all salinity conditions, but allowed diatom Phaeodactylum tricornutum to dominate. Community growth rate was higher under high light, but also more variable between salinity conditions. The strongest negative effects of nutrient limitation (N, P, and both nutrients together), both on growth rate and taxonomic diversity, were observed in the highest salinity treatment. In the freshwater treatment with the highest proportion of green algae Monoraphidium sp., N-limitation did not inhibit phytoplankton community growth and P-limitation had a more profound negative effect on community performance. Decreasing salinity appeared to decrease community C:N and C:P ratios. This shift is in opposition to the increasing C:N and C:P predicted as a consequence of other climate change-related drivers. Our results emphasise the importance of a trade-off between salinity and resource limitation in functioning of phytoplankton communities and suggest that future freshening of the Baltic Sea is likely to modify phytoplankton community composition and performance.
  • Tuomela, Nea (2022)
    Climate change causes changes in the Arctic lakes, such as shortening of the ice-covered period and changes in hydrology as well as vegetation of the drainage area around the lakes. With these shifts in the function of the ecosystems, dissolved organic matter drainage from terrestrial sources is expected to increase. Terrestrial, allochthonous DOM is more refractory, higher molecular weight organic matter, which is less available to bacterial consumption. Alterations in the DOM pool of the lake may change the bacterial community composition, which could in turn alter the lake ecosystem. Four ice-covered lakes in Kilpisjärvi region were sampled in spring 2021. Water samples were filtered and analyzed for dissolved and particulate nutrients and carbon. Coloured dissolved organic matter and fluorescent dissolved organic matter properties were defined. Bacterial community composition was determined with multiplex polymerase chain reaction and sequences analyzed with DADA2 pipeline. Principal component analysis (PCOA) was done to visualize differences between lakes, and distance-based redundancy analysis (dbRDA) was used to detect any associations between dissolved organic matter properties and bacterial community composition. The lakes had low nutrient and carbon concentrations and had mainly similar properties of dissolved organic matter. However, P3 surface water had higher nitrate and total dissolved nitrogen concentrations. Optical properties in P3 surface water, Peak T, Peak M, biological index and humification index, indicated autochthonous production and lability of organic matter. This was reflected also in bacterial community composition by higher relative abundance of Gammaproteobacteriales. Lake P3 had also higher relative abundance of Cyanobacteria, which could be the cause for labile organic matter in the site. Sites P2 and P3 had similar bacterial community compositions, which is likely due to the sites forming a lake chain and sharing the same catchment area. The sites were oligotrophic and low nutrient environments as expected in the arctic environment. One of the sites had indications of more labile organic matter, which was reflected in the bacterial community structures. In the future shorter ice-cover period may induce autochthonous production such as Cyanobacteria, which reflects in the bacterial community. Changes in the DOM properties and bacterial communities can alter the whole food chain. with A more comprehensive study on this issue could be useful way of understanding the carbon cycling and impacts of climate change to the subarctic lakes.
  • Berglund, Nora (2022)
    In Finland and in many other European countries, indoor housing of dairy cattle has been increasing at the expense of grazing. According to Finnish legislation, only dairy cows housed in tie-stalls are obligated to graze for 60 days per year between May and September. Pressure to intensify production leads to increase in herd sizes, regional concentration, lack of suitable pastureland near large barns, and automation of milking. Conversely, grazing is regarded as important for animal welfare, maintenance of biodiversity and cultural landscapes. Farmer perceptions towards grazing have not been studied in Finland comprehensively, which need to be understood better in order to provide adequate support for sustainable management of grazing. The research aims at gaining understanding of the external and internal factors driv- ing the farm-level decision making related to grazing regimes. Concept of good farming ideal is used to examine farmers’ decision-making. The data was collected from 26 cattle farms with a gradient of grazing from zero to maximum. Firstly, an online questionnaire was sent out to farmers and secondly, semi-structured inter- views were conducted with 7 dairy producers, to further explore farmer views about grazing, biodiversity, and animal welfare. The results show farmers who practice grazing to perceive it more positively than the farmers who do not graze. Some of the farmers who grazed seemed to consider it almost as an intrinsic value, whereas farmers with no grazing saw it as an inef- ficient production method, which they were afraid would become an obligation. The most im- portant internal factors driving decision-making about grazing based on the questionnaire and interviews, were animal welfare, decreased workload because of grazing, infrastructure of the farm, economic aspects, and benefits of grazing to biodiversity and landscape values. Exter- nal factors found to affect the decision of grazing were incentives, regulations, and consumer expectations. Animal welfare was found to be a basis for production for many and the most important feature valued for good farming, to which grazing was seen to contribute. The re- sults imply subsidies regarding grazing should be higher for grazing to be considered profita- ble and more enjoyable by farmers.
  • Pykäri, Janina (2022)
    Light is crucial for aquatic ecosystems, as photosynthesis supports the higher trophic levels. Light attenuates in water due to absorption and scattering by optically active substances (OAS), the main ones in coastal environments being chlorophyll-a (chl-a), particulate matter and coloured dissolved organic matter (CDOM). Light attenuation measurements are also important indicators of many environmental changes. Traditionally, Secchi depth has been used to monitor changes in light attenuation. However, Secchi depth (ZS) is a not an accurate estimate of light attenuation, and conversion to light attenuation coefficient (Kd) is needed to study light conditions as aquatic organisms observe them. Therefore, calibration between methods is important. In this study, light attenuation was estimated with Secchi disc, a light meter and light loggers to scrutinize the possibilities of autonomous measurements in this context. The aims of the study were 1) to compare three methods for estimating light attenuation and 2) to identify the environmental drivers affecting the relationships and accuracy of these methods, and 3) to assess the possibility of using conductivity as a proxy for light attenuation. The main hypotheses were that the differences in conversion between ZS and the two sensor-based methods in different concentrations of optically active substances can be explained by contribution of scattering to light attenuation, and that variation in different Kd-estimates is due to the different measurement spectra. The effect of three OASs (chl-a, particulate matter, CDOM) on differences among light attenuation estimates were quantified in Pohjanpitäjänlahti bay. Light attenuation was mainly controlled by CDOM, followed by particulate matter and chl-a. Conductivity was found to be a good proxy for light attenuation. However, there was a mixed signal if the differences among methods could be explained by OAS concentrations or conductivity, as the hypotheses were supported with one device pair but not with the other. Therefore, the differences among light measurement methods might stem from the characteristics of the devices or measurement errors. However, all the methods were found suitable for tracking changes in light attenuation and a summary table of the advantages and disadvantages of each method is presented to help choose a suitable method to estimate light attenuation e.g., in future studies or environmental monitoring.
  • Kivelä, Linnea (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.
  • Nivalainen, Pinja (2022)
    Eläinten tunnemaailma on meille melko vieras. Sen takia on tärkeää tutkia, millaiset asiat vaikuttavat siihen, miten tulkitsemme niiden tunteita. Tunteiden tulkintaan voivat vaikuttaa tulkitsijan omat kokemukset. Tämän tutkielman tarkoituksena on tutkia sitä, mitkä asiat vaikuttavat siihen, kuinka hyvin eläintarhakävijät tunnistavat villieläinten tunteita. Erityisesti keskityn siihen, miten vastaajan sukupuoli, ikä, kasvuympäristö ja lapsuuden ja aikuisuuden aikaiset eläinkokemukset vaikuttavat eläintarhakävijöiden kykyyn tunnistaa eläinten tunteita. Tutkimus tehtiin kyselytutkimuksena Korkeasaaren eläintarhassa kesällä 2021. Osallistujille näytettiin videolta eläin ja heidän tuli kertoa, onko eläimen tunnetila neutraali, myönteinen vai kielteinen ja onko se rauhallinen vai kiihtynyt. Tutkimuksessa tutkittiin tiikereiden, berberiapinoiden ja markhorvuohien tunnetilan tunnistamista. Osallistujista kerättiin taustatietoja, kuten ikä ja sukupuoli. Tulosteni perusteella eläinlajilla on vaikutusta tunnetilan tunnistamiseen. Tiikerin myönteisyys tai kielteisyys osattiin arvioida huonommin kuin berberiapinan. Myös vastaajan ikä vaikuttaa tunteiden tunnistukseen. Vanhemmat tunnistivat myönteisyyden tai kielteisyyden nuorempia ihmisiä heikommin. Sukupuoli vaikuttaa yhdessä iän kanssa kiihtyneisyyden tunnistamiseen. Kiihtyneisyyden tunnistivat paremmin 18–30-vuotiaat naiset kuin 61–75-vuotiaat naiset, mutta muiden ryhmien välillä ei havaittu merkitseviä eroja. Kiihtyneisyys tunnistettiin myös paremmin, jos eläimet ovat olleet osana vastaajan elämää vain lapsuudessa sen sijaan, että ne olisivat olleet aina osana elämää. Tulosten perusteella voidaan päätellä, että ihmiset tunnistavat eri eläinten tunteet eri tavalla ja ihmismäisempien eläinten tunteet ovat muita helpommin tunnistettavissa. Iällä ja sukupuolella voi olla vaikutusta ihmisten kykyyn tunnistaa eläinten tunteita. Myös eläinkokemus vaikuttaa ihmisten kykyyn tunnistaa tunteita ja kokemus ei ole sama kuin tiedon omaksuminen. Tuloksiani voidaan hyödyntää esimerkiksi ympäristökasvatuksessa.
  • Lehto, Reetta (2022)
    The main motivator of this thesis was to discover the importance of Chaoborus in a eutrophic and dystrophic lake and evaluate suitable restoration methods to enhance the state of the study lake. The role of Chaoborus in the study lake, Lake Jouttenus, was studied with sampling of both the water column and the sediment, echo-surveys, and diet analyses of fish. The sampling was planned as comprehensive, and the sampling stations were distributed across the whole lake area to examine the density and distribution of Chaoborus. The deeper areas of the lake were emphasized more in sampling because Chaoborus tend to favor those areas. The Chaoborus density was calculated with stratified sampling, which gives a more precise mean density estimate than simple random sampling. In addition, fish were caught on four (4) study occasions to find out if they had included Chaoborus in their diets. The mean density of Chaoborus in Lake Jouttenus was a little lower than expected, only 271 individuals/m2 in areas ≥2 m depth. The highest density of larvae was found from mid-depths between 6.0-7.9 m in the sediment. Only the deepest areas (≥8 m depth) had limnetic Chaoborus and more limnetic than benthic larvae. The mean length of larvae was 8.4 mm in the sediment and 9.0 mm in the water column. The length distributions appeared to be unimodal. Echo-surveys confirmed that the larvae occurred in the water column only in the deepest area in the north of the lake where the hypolimnion had a low oxygen concentration below 4 m depth. The diet analyses showed that roach and perch had eaten Chaoborus but the number of Chaoborus was high only in the diet of roach in early July. In comparison with other studied lakes, the density of Chaoborus was the lowest in Lake Jouttenus. In addition, the mean length of benthic Chaoborus in Lake Jouttenus was lower than in the other studied humic lakes. The distribution of limnetic Chaoborus appeared as restricted to the deepest areas in the lake and elsewhere the larvae occurred only in the sediment. The slow growth of Chaoborus and their low mean density could be explained by the lack of an efficient refuge and probably also the lack of resources. The larvae were unable to reach the epilimnion and their prey safely at daytime and/or the amount and quality of food items for the larvae were poor. The darkness caused by humic substances and low oxygen concentration in the hypolimnion created a refuge for the limnetic larvae only in the deepest area of Lake Jouttenus. Roach and perch ate Chaoborus occasionally. However, mass removal of fish is not recommended as it would decrease the predation pressure by fish on Chaoborus and increase the risk of Chaoborus population growth at the deepest areas and enable their range to extend. Instead of mass removal of fish all methods that aim in reducing the humic substances in the water especially at the lake catchment area might enhance the state of the lake. The clarification of water would diminish the living conditions for Chaoborus in long-term and help with controlling the other troubling factors such as Gonyostomum semen blooms in the study lake.
  • Lahtinen, Oskari (2022)
    Agriculture is emitting ~6.2 Gt CO2-Eq. annually, which accounts for ~12 % of the total annual net anthropogenic greenhouse gas (GHG) emissions globally. Agriculture emits N2O and CH4, and it is responsible globally for ~79% of N2O emissions and ~40% CH4 emissions. These emissions are vital since N2O and CH4 are 273- and 27-times greater GHG than CO2, respectively. There are many different food production systems developed to reduce these emissions. One of the most promising systems is agroforestry. Agroforestry is a complex system where trees and/or shrubs are interacting with crops and/or animals. Agroforestry is an old practice which can provide plenty of advantages, e.g., increased yields, increased biodiversity, and increased carbon sequestration. Therefore, the interest towards it has been increasing in the last decades. In this master’s thesis the different maize production systems in Zambia were studied. The comparison was conducted between low-input maize monoculture where only external input was maize seed for sowing; high-input maize monoculture where mineral fertilizers and seeds for sowing were used; and maize-Faidherbia albida agroforestry system where only external input was maize seed for sowing. The goal of this master’s thesis was to find out, which production system is having the lowest climate change potential in the Central Province of Zambia. To conduct this study, Life Cycle Assessment (LCA) -method was used. Two cases were used in LCA, i.e., Case 1 with functional unit (FU) of 1000 kg d.m. maize grain, and Case 2 with FU of 3 ha maize field. Also, four sensitivity analyses were conducted. The result from this study indicates that agroforestry system had the lowest climate change potential in both cases, and in most of the sensitivity analyses. Only exception was found in the sensitivity analysis where above-ground biomass of F. albida was substituting hydropower. In this sensitivity analysis the monoculture without external inputs had the lowest climate change potential. Since the food production in Zambia must increase in the future to reduce the hunger, the high-input system or agroforestry system are more favourable options as they produce higher crop yields. When taking the climate change potential into account, according to the results of this thesis, the agroforestry system provides more benefits. The results of this thesis can provide new knowledge which could be used in the future decision-making processes. Yet, in the future studies, more complex agroforestry systems with more sustainability pillars should be considered to provide improved information for decision-making.
  • Blom, Sonja (2022)
    Pain is a subjective feeling often difficult to interpret or study and thus, pain of those unable to communicate their pain is difficult to recognize. According to the new definition of pain by IASP (Raja et al 2020), verbal description is only one of the many behaviours that can be used to express pain, and the inability to communicate pain does not negate the possibility of experiencing it. This addition to the definition points out that non-human animals, too, even if they cannot express it in words, are capable of both experiencing and communicating pain. Can we as humans interpret a state of pain in an animal in a trustworthy way – and in a manner that would be respectful and non-invasive to the animal? Infrared thermography (IRT) is a technology based on using infrared radiation instead of normal light to form images. These images can be used to quantify the surface temperature of an object with high resolution. The intensity of the radiation emitted by the object being imaged depends on the surface temperature and for this reason thermal imaging enables detecting and measuring changes of surface temperature. Pain and stress might manifest physiologically as activation of the autonomic nervous system, which in turn might result in changes in surface temperatures of the body. These changes might be detectable with a thermal camera. If we could establish a link between certain intricate temperature changes of the head area to certain type of activation of the sympathetic nervous system resulting from pain, thermal imaging could have the potential to detect this. In this study I investigated if there were detectable temperature changes in animal patients before and after a standard examination conducted to each patient admitted to the Wildlife Hospital of Helsinki Zoo, where my data was gathered. Another question was whether the patients that had pain differed in their temperature changes as compared to other patients. The question at the heart of my research was whether there would be a change in peripheral facial temperatures of patients before and after the examination. Another question was whether thermal patterns would be different for pain- and non-pain patients. I found that for some parameters, the temperature differences between pain- and non-pain patients were indeed different, for example the crown temperature of birds seemed to change with examination for patients without pain but not for patients with pain. A more prominent finding was that temperatures decrease across many parameters after an examination as compared to prior to it, across all or many patient groups. My research does not univocally show that thermal imaging could be used to detect pain; rather it affirms the thought that the measurement of changes in peripheral temperatures could be a potential window to non-invasively detect some changes of activation of the sympathetic nervous system in animals.
  • Kangas, Jonna (2022)
    Climate change is expected to cause salinity change in the Baltic Sea and therefore may affect organisms living in the Baltic such as plankton. The microbial loop is an important part of the plankton food web. It consists of heterotrophic bacteria, nanoflagellates and ciliates and is connected with the classic plankton food chain through interactions with primary producers and mesozooplankton. Therefore, salinity affects the functioning of the microbial food web not only directly, but also through salinity induced changes on primary producers and mesozooplankton. In this master’s thesis I studied the effects of salinity change on microbial loop components bacteria, nanoflagellates and ciliates in an outdoor mesocosm experiment containing four salinity treatments with salinities of 3.5, 5.5, 7.5 and 9.5, three replicas each. The experiment took place offshore at the Tvärminne Zoological Station. Bacteria were sampled from the mesocosms every other day and nanoflagellates and ciliates every 6th day. Bacteria were analysed with the flow cytometer, nanoflagellates with epifluorescent microscopy and ciliates using an inverted microscope. The effects of salinity on microbial loop components were statistically tested using linear mixed effects models. Results of the experiment show that salinity had an indirect effect on microbial loop components through changes in mesozooplankton composition. There were significant differences between high and low salinity treatments in bacteria abundance and composition, the interaction strength between HNFs and bacteria and in the mean cell size of ciliate communities. These were mainly caused by differences in mesozooplankton community structure between salinity treatments, which had cascading effects on the strength of top-down and bottom-up control on the trophic levels of the microbial loop, leading to changes in bacteria abundances and composition. Based on the results of this thesis, more studies are needed to detect the effects that changes in the composition and functioning of the microbial loop might have on the ecosystem. Further research should also focus on the significance of the structure and diversity of the communities within the microbial loop as well as the functional roles of different species in the microbial food web.
  • Kontio, Salla (2022)
    Spontaneous and voluntary movements of infants effectively reflect the developmental integrity of brain networks. When it comes to the research of motor development, the use of intelligent technology has shown to provide objective, automated, and scalable methods for movement assessment. In addition to intelligent technology, research on the usage of surveys – in this case parental surveys – has looked at the untapped potential that parental viewpoint. Guardians have a unique and holistic image of the child’s development, thus data from parental surveys could be used to further help us to assess infant’s development. For this study, I studied how the parents’ time estimate on the positions their child spends time in holds up against the machine-learning based data obtained with the smart jumpsuit. Using the data acquired from the smart jumpsuit during the recordings, we can see the amount of time the child spends in each position. Aim was to study the relationship between these variables and gain further understanding on the utilization of parental perspective in the assessment of motor development. Data was collected from 19 video recordings and videos were annotated with Anvil video annotation software for child’s posture and movements, and the annotations were used for training a machine learning-based classifier of the smart jumpsuit. Only data regarding postures was extracted for further analysis. Parental surveys were carried alongside of recordings. In the survey of parental estimate, we asked the parent to assess how much time the child spends in a specific posture. Positions which the survey focused on were prone, supine, side, sitting, crawling, and standing. Data from the recordings as well as data from parental surveys were visualized with radar plots. In addition, correlation was visualized in a linear regression. Positions which had both correlation of higher than 0.5 and a significant p-value were sitting (p < .001**), crawl posture (p < .05*), standing (p < .001**), and supine (p < .05*). Results suggested that parents were successfully assess the time spent in following postures: sitting, crawling, standing, and supine. This indicates that parents have a holistic understanding of their child’s motor development, and the knowledge could be useful in the overall assessment of development, especially when it comes to children with developmental delay. The parent’s ability to accurately assess a child’s motor development helps the parent support the child’s development.
  • Mielikäinen, Lotta (2022)
    Sex determination in humans occurs via the sex chromosomes, X and Y. Females carry two X chromosomes while males are XY individuals. Due to this X chromosome distribution the expression of X-linked genes is balanced with a process called X chromosome inactivation (XCI) where one of the X chromosomes is silenced, selected either randomly or preferentially, in early female embryogenesis. X-linked disorders are more prevalent in males as, generally, in females the effects of a disease-causing variant in other of the X chromosomes can be compensated with the normal allele on the other X whereas male express the allele on their only X chromosome. However, cases of heterozygous females manifesting an assumed recessive X-linked disorder have been reported although the symptoms are usually milder in these cases than in males. One suggested reason behind this is a skewed XCI where the majority of female’s cells express the mutated allele. The main goal of this thesis was to examine how often heterozygous female carriers have symptoms of X-linked disorders. To achieve this goal, likely pathogenic and pathogenic X-chromosomal variants were retrieved from the ClinVar database and their global allele frequencies were examined from The Genome Aggregation Database (gnomAD). The genetic and phenotypic data of 500,000 individuals from the UK Biobank (UKB) were used to conduct genetic association analyses between the ClinVar variants and quantitative traits related to their reported phenotypes. The associations were tested in males and in females separately to allow for examination of sex-specific effects and inheritance models via the comparison of effect sizes. 89 (likely) pathogenic variants were detected from UKB, and the majority of these were extremely rare with minor allele frequency below 0.01% in the global population. 11 and 27 of them were selected for the association analyses for the male and female populations of UKB, respectively, after filtering out variants that did not meet requirements such as enough carriers. One to five quantitative traits were chosen for each variant resulting in 28 tests among males and 87 among females. These analyses showed few significant associations while the majority of the tested variants were observed to have no effects on the chosen trait. The most statistically significant association was observed with variant rs137852591 on the gene AR (androgen receptor) in males. The variant was related to lower muscle mass and shorter height that are associated partial androgen insensitivity syndrome reported in ClinVar for this variant. Nominally significant associations were seen with this variant and the same traits in heterozygous females suggesting that there might be, indeed, symptoms of the syndrome in females as well. Additionally, in both sexes variants on gene G6PD seemed related to traits that are characteristics of glucose 6 phosphate dehydrogenase deficiency. The limitations of these databases must be taken into account when conducting studies utilizing them. However, this thesis demonstrated that heterozygous female carriers may have symptoms of X-linked disorders assumed to have recessive inheritance pattern. In the future, a wider set of phenotypes could be used to investigate the impacts of the X-linked variants more broadly.