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  • Valkonen, Sami (2014)
    Microvesicles (MVs) are lipid bilayered membranous vesicles containing functional lipids, proteins, RNA and DNA that are produced by most cells. The physiological significance of MVs has become evident, and increased MV counts and the contents of MVs are nowadays also associated with different pathophysiological phenomena. The goal of the field is to use MVs as diagnostic and therapeutic tools. To achieve this, the understanding of the mechanisms of the functions of MVs should be understood better and additionally, reliable methods for the quantification and characterization of MVs should be developed and standardized. The aim of the study was to determine differences in platelet-derived MVs produced by different activation mechanisms. The second aim was to set up and optimize a protocol based on the reaction of sulphur, phosphate and vanillin (SPV) for measuring lipid content of MVs. The third aim was to study the effect of thrombin and proteinase inhibitor PPACK to the vesiculation of platelets. Platelets were isolated from the whole blood of healthy volunteers and vesicles were produced by platelet agonists mediating thrombogenic activation (thrombin and collagen, TC), pathophysiological activation (lipopolysaccharide, LPS) and Ca-ionophore (A23187) as positive control for vesiculation. Quantification and size determination of produced MVs was done using Nanoparticle Tracking Analysis (NTA). MVs were characterized by protein content using bicinchonic acid assay (BCA) and by lipid content using SPV-reaction. MVs had great activation-dependent differences in the lipid and the protein content. Activation with Ca-ionophore produced the most MVs, but the lipid and protein content was only a fraction from (patho)physiologically induced MVs. Only TC increased vesiculation. Vesicle subpopulations had significant difference in lipid content. Thrombin and proteinase inhibitor PPACK mediated inhibition of platelet formation in all of the activations, but the effect was not statistically significant. The mechanism of inhibition was likely to be proteinase inhibitor mediated. The isolation of vesicle populations using differential centrifugation proved to isolate studied populations only partially and the quantification method with NTA was susceptible to concentrated samples. SPV protocol reacted with different intensity to different lipids. In the future, quantification and isolation methods for MVs and the subpopulations of MVs should be improved. Additionally, to understand the physiologically relevant mechanisms of platelet-derived vesicle formation, the inhibitor experiments with PPACK should be continued, because the number of replicates was too low to see significant effects due to a large donor-dependent deviation. Since MVs are heterogenous cellular multitools affecting varying (patho)physiological phenomena, optimization and standardization of methods should be continued in order to study MVs properly.
  • Hietala, Ville (2018)
    Antibioottiresistenssi yleistyy infektioita aiheuttavien bakteereiden keskuudessa. Infektioita hoitaessa joudutaan siten miettimään uusia tapoja infektioiden parantamiseksi. Yhden vaihtoehdon tarjoaa bakteriofagiterapia. Siinä infektiota sairastavalle annetaan bakteriofageja, jotka infektoivat bakteereita, lisääntyvät niissä ja tuhoavat ne. Kirjallisuudessa on runsaasti lupaavia esimerkkejä tästä terapiamuodosta. Kuitenkin bakteriofagituotteiden on oltava tarpeeksi puhtaita, erityisesti siinä tilanteessa, jos niitä annetaan suonensisäisesti. Gramnegatiivisten bakteereiden tärkeä rakenneosa on lipopolysakkaridi eli LPS, joka ihmisen verenkiertoon päästessään voi olla vaarallinen. Siksi, mikäli bakteriofagit on tuotettu gramnegatiivisissa bakteereissa, LPS:t on kyettävä poistamaan näytteistä. Tässä Pro Gradu-työssä tutkittiin viidessä eri koejärjestelyssä, kuinka erilaiset tekniikat ja niiden yhdistelmät vaikuttivat bakteriofagien ja LPS:n määrään näytteissä. Lisäksi arvioitiin SDS-PAGE-geelissä näytteiden proteiinikoostumusta. Näytteistä mitattiin myös dsDNA-pitoisuus. Tutkitut tekniikat olivat ultrafiltraatio, anioninvaihtokromatografia, oktanoliuutto ja kaupalliset endotoksiininpoistotuotteet EndoTrap- ja Pierce high endotoxin removal-pylväät. Koejärjestelyssä 1 suodatettua bakteriofagilysaattia puhdistettiin ensiksi oktanoliuutolla, sitten ultrafiltraatiolla, anioninvaihtokromatografialla ja lopuksi uudella ultrafiltraatiolla. Endotoksiinipitoisuus laski eniten kromatografiassa mutta toisen ultrafiltraation jälkeen se pysyi varsin samana. Tiitteri pieneni vain oktanoliuutossa ja kromatografiassa (jossa osittain laimenemisen takia), kun ultrafiltraatioissa muutos edeltävään tiitteriin oli varsin pieni. Lopuksi näytteissä oli keskimäärin n. 15 EU (endotoksiiniyksikköä)/10^9 pfu (plaque forming unit). Toisessa koejärjestelyssä aloitettiin ultrafiltraatiolla ja sen jälkeen näytteet puhdistettiin joko EndoTrap- tai Pierce-pylväällä. Kaikki vaiheet poistivat endotoksiineita. Ultrafiltraatio pienensi hieman tiittereitä mutta EndoTrap-pylväs ei. Pierce-pylväässä tiitterin aleneminen oli huomattavaa, jolloin EndoTrap-pylvään jälkeen näytteissä oli keskimäärin 0,0574 EU/10^9 pfu ja Pierce-pylvään jälkeen 33700 EU/10^9 pfu eli suhde oli jopa enemmän kuin lysaatissa. Kolmannessa koejärjestelyssä aloitettiin ultrafiltraatiolla, jonka jälkeen oli kromatografia ja uusi ultrafiltraatio. Ensimmäisessä ultrafiltraatiossa tiitterit pienenivät jonkin verran mutta kromatografian ja toisen ultrafiltraation jälkeen se oli varsin sama, kuin ensimmäisen ultrafiltraation jälkeen. Endotoksiinipitoisuus pieneni taas eniten kromatografiassa ja se oli varsin sama toisen ultrafiltraation jälkeen, jolloin puhdistetuissa näytteissä oli keskimäärin 57,1 EU/10^9 pfu. Neljännessä koejärjestelyssä lysaattia ultrafiltroitiin ensiksi, sen jälkeen ruiskutettiin kromatografialaitteeseen, ultrafiltroitiin uudestaan ja sen jälkeen puhdistettiin joko EndoTrap- tai Pierce-pylväällä. 1. ultrafiltraatio pienensi taas hieman tiitteriä mutta se oli varsin sama EndoTrap-pylväällä puhdistetussa näytteessä. Pierce-pylvään kanssa tiitteri pieneni taas huomattavasti. Endotoksiinipitoisuudet pienenivät taas kaikissa vaiheissa, jolloin EndoTrap-pylväällä puhdistetussa näytteissä oli keskimäärin 0,0839 EU/10^9 pfu ja Pierce-pylväällä 5480 EU/10^9 pfu. Viides koejärjestely oli muuten sama, kuin koejärjestelyn 2 Pierce-pylväs järjestely mutta korkeamman NaCl-pitoisuuden eluutiopuskurilla ja suuremmalla näytetilavuudella. Tällöin tiitteri ei pienentynyt yhtä paljon, endotoksiinipitoisuus oli lopussa vain hieman korkeampi kuin koejärjestelyssä 2 ja loppuun asti puhdistetussa näytteessä oli keskimäärin 71,21 EU/10^9 pfu. SDS-PAGE-tutkimuksessa ja dsDNA-mittauksissa näkyi, että ultrafiltraatio yksin riittää poistamaan muut bakteeriperäiset proteiinit ja dsDNA:n. Tosin koejärjestelyssä 1 käytetty oktanoli saattaa vaikuttaa dsDNA:n puhdistumiseen ultrafiltraatiossa. Töissä onnistuttiin tuottamaan näytteitä, joissa sekä riitti bakteriofageja, että endotoksiinipitoisuus oli pudonnut huomattavasti. Kun huomioidaan käytännöllisyys ja nopeus, parhaaksi tavaksi puhdistaa LPS:t valikoitui ultrafiltraatio yhdistettynä EndoTrap-pylvääseen. Johtuen bakteriofagien ja LPS:ien monimuotoisuudesta, ei toisella bakteriofagilla välttämättä päästä samoihin
  • Näppilä, Meeri (2023)
    The coastal Baltic Sea hosts a very special ecosystem due to its brackish water and high seasonality. However, there is little research on the seasonality of the ecosystem and organic matter (OM) cycling, as many studies are conducted during summer or in areas without ice cover. This study is based on material collected continously over one year (Oct 2012-Oct 2013) by a sequencing sediment trap at 7-56 day intervals. It will provide knowledge of the seasonal variability in the vertical flux of organic material (TOC) and its sources (C:N, δ13C, δ15N) as well as dinoflagellate resting stages (dinocysts). Dinoflagellates are important primary producers in the Baltic Sea, some of which produce well-preserving resting stages (cysts). The seasonal changes in the fluxes and source of OM and dinoflagellate species' seasonal succession are not only ecologically interesting, but as both are used as sediment paleo proxies, provide more information for reliable reconstruction models for the Baltic Sea in the past. The seasonal sedimentation of the coastal Baltic Sea was strongly impacted by seasonality, with strong primary production causing high OM sedimentation rate during spring bloom and lack of primary production causing very small sediment flux in winter. During the fall resuspension played a big role in sedimentation. Only three species of dinocysts were present in the trap samples and most of the dinocyst flux of the whole year was formed by Biecheleria baltica. Most important drivers of B. baltica abundance and encystment were likely temperature signals for encystment at 6 °C and a small bloom under ice that got B. baltica a head start for competition in the spring bloom. Changes in terrestrial material input were not clearly visible in the sedimenting material, but primary production had an enriching influence on the OM stable isotopic composition and elevated the C:N ratio due to reaching limiting conditions of N. During winter long sea-ice cover and cold-water temperature created anomaly depleted isotopic composition similar to those in Arctic ecosystems. Even with long time-series of phytoplankton spring blooms, more knowledge is needed of links to environmental characteristics to better understand how climate change and eutrophication will impact the spring bloom in the Baltic Sea. Especially more information of under ice conditions are needed for a better understanding of the past, present and future of the Baltic Sea.
  • Siitonen, Susanna (2005)
    In this thesis I used paleolimnological methods to study changes in two lakes in Kilpisjärvi region, Somas and Vallijärvi, during the last c. 400 years. I examined the remains of cladocera preserved in sediments to find out species composition and population size in the past. The objective of this study is to reveal if the cladoceran species compositions have changed in the lakes and what is has been driving these changes. In addition, I will use cladoceran resting eggs from the sediment of lake Somas to examine the applicability of resting eggs as a new paleolimnological method. In April 2002 I cored sediment sequences from the lakes and sliced them into 0,5-1 cm subsamples. The samples were dated with led isotope, 210Pb, to reveal the sedimentation rate. From the sediments I determined the organic carbon content, counted the proportions of different cladoceran species, the absolute numbers of individuals and the yearly accumulation of cladocera to the sediment. In addition I calculated the relative share of resting eggs. I examined relationships between the samples and between the samples and measured environmental variables with a set of multivariate methods (DCA, DCCA, PCA, RDA). I tested a previously created cladoceran-water depth model to Vallijärvi data in order to reconstruct past water level development in the lake. In the turn of the last century a distinct interface between two different species compositions can be seen in both lakes. Also the accumulation of cladocera into the sediments has increased in both lakes, and the planktic species have out paced the littoral ones during the last century indicating an increase in productivity. Also sedimentological processes have develop similarly in the lakes. Due to the location of the lakes, their differing morphology and history the changes in biological and sedimentological processes have been stronger in the lake Vallijärvi. The model on past water levels seemed to perform well in the lake Vallijärvi. Water level reconstruction was not, however, problem free, as similar development in species composition could be a consequence of increase in productivity. The amounts of resting eggs seemed to follow negatively the air temperatures of the open water period. However, before the resting egg method can be applied as a paleolimnological indicator, a more extensive data set on the relationship between resting eggs and temperatures is required.
  • Halonen, Minna (2012)
    Kaupungistumisen lisääntyessä luonnontilaiset elinympäristöt pirstaloituvat, jonka seurauksena kaupunkeihin tarvitaan lisää viheralueita monimuotoisuuden säilyttämiseksi. Jotta kaupunkeihin saataisiin lisää elämää tuovia virkistäviä viheralueita, on viherkattoja käytetty muiden kaupungin viheralueiden rinnalla. Viherkatot ovat nimensä mukaisesti rakennusten katoille rakennettuja viheralueita, jotka voivat olla sekä tasakattojen että vinojen kattojen päällä. Tavallisesta, maan pinnalla sijaitsevasta viheralueesta poiketen viherkatolla on rajallinen maaperän paksuus, sillä sen pohjana on talon kattorakenne. Viherkatot ovat osa kaupunkien ekosysteemipalveluita, joilla tarkoitetaan ihmisen saamia hyötyjä ekosysteemeistä. Viherkatoista saatavat hyödyt ovat monenlaisia: hiilen sitominen yhteyttämisessä ja hapen vapautuminen ilmaan, elinympäristöjen tarjonta, melun väheneminen kasvillisuuden avulla sekä pölytys ovat esimerkkejä viherkattojen tarjoamista ekosysteemipalveluista. Tämän tutkimuksen tarkoituksena oli selvittää, voisivatko viherkatot toimia korvaavina elinympäristöinä katoaville elinympäristöille ja uhanalaisille kasvilajeille viherkattojen eristyneisyydestä ja kaupunkiympäristöstä huolimatta. Katoavilla elinympäristöillä tarkoitetaan usein maankäytön muutosten takia harvinaistuneita elinympäristöjä, kuten niittyjä ja paahdeympäristöjä. Erityisesti kasvilajeista putkilokasvit, joihin tutkimus keskittyy, ovat uhanalaistuneet elinympäristöjen katoamisen vuoksi. Niittyjen ja ketojen umpeenkasvu, ilmastonmuutos ja kaupunkien rakentaminen ovat suurimmat syyt uhanalaistuneiden ja silmälläpidettävien kasvilajien lisääntymiseen. Viherkattojen kasvilajistoa inventoitiin kesän 2012 aikana pääkaupunkiseudulla 51 viherkatolla keskittyen putkilokasvien esiintymiseen. Viherkatoilta löydettiin yhteensä 192 putkilokasvilajia ja 27 sammal- ja jäkälälajia. Näistä putkilokasveista kahdeksan on luokiteltu Punaisen kirjan uhanalaisuusluokituksen mukaisesti uhanalaisiksi ja Retkeilykasvion luokittelun mukaisesti kymmenen lajia osoittautui harvinaisiksi. Viherkatoilta löydettyjen uhanalaisten ja harvinaisten lajien luontaisia esiintymisalueita olivat pääosin kuivat niityt, kedot, tienpientareet, joutomaat ja kallioiset alueet. Näin ollen viherkatot voisivat toimia korvaavina elinympäristöinä edellä mainittujen elinympäristöjen harvinaistuville ja uhanalaisille kasvilajeille. Viherkattojen kasvillisuutta selittäviä tekijöitä tarkasteltaessa harvinaisten ja uhanalaisten lajien määrää selittää parhaiten kasvualustan syvyys. Tulokset kasvualustan syvyyden merkityksestä ovat selviä: mitä syvempi kasvualusta, sitä enemmän viherkatoilla esiintyi harvinaisia ja uhanalaisia kasvilajeja. Muista tekijöistä uhanalaisten ja harvinaisten kasvilajien esiintymiseen vaikuttavat viherkaton pinta-ala, ikä, viherkaton kokonaislajimäärä ja viherkaton korkeus. Näytealan etäisyydellä reunasta ei havaittu olevan merkitystä uhanalaisten ja harvinaisten lajien esiintymiseen.
  • Matikka, Eveliina (2019)
    Suomen ilmasto-olosuhteissa viherkattojen toiminnasta ja vedenpidätyskyvystä on vielä niukasti tietoa. Tämän Pro gradu -tutkielman tavoitteena on selvittää, millainen viherkattotyyppi olisi optimaalisin hulevesien hallintaan. Tutkielmassa selvitetään kokeellisesti sekä kirjallisuuden avulla viherkattojen kasvillisuuden sekä kasvualustan paksuuden ja koostumuksen vaikutuksia kattojen toimintaan. Tutkielman koeasetelmaan kuului kolme erilaista viherkattovaihtoehtoa. Kaikki on perustettu tiilimurskapohjaiselle kasvualustalle. Kasvillisuutena on joko sammalia, maksaruohoja, kukkakasveja ja heiniä kasvava valmismatto (3 kpl) tai taimi-istutuksin ja kylvämällä perustettu taimikylvökatto (3 kpl). Näiden lisäksi on yksi valmismattokatto, johon on lisätty 1 cm:n kerros biohiiltä. Taimikylvön kasvillisuus koostuu ruohovartisista kukkakasveista ja parista maksaruohosta. Vedenkulkua koeasetelmassa seurattiin kahdella sademittarilla sekä seitsemällä valuntamittarilla, jotka seurasivat sadannan ja valunnan määrää sekä ajoitusta. Lisäksi kolmessa kattoruudussa oli jatkuvatoimiset kosteus- ja lämpötilasensorit eri syvyyksillä: 2 cm, 5cm, 8 cm ja 8 cm etureunassa. Tutkimusten avulla selvitetään 1) miten kasvualustojen vedenpidätyskyvyt eroavat, 2) mikä käsittely hidastaa valuntaa eniten, 3) miten kasvualustojen lämpötilat eroavat ja 4) mistä erot johtuvat. Biohiilen uskotaan lisäävän veden pidättymistä sateen yhteydessä ja hidastavan veden poistumista sadetapahtumien välillä. Valmismattojen uskotaan pidättävän vettä paremmin kuin taimikylvön, koska runsaampi kasvillisuus pidättää enemmän vettä. Pienimmän valunnan oletetaan vapautuvan hitaimmin. Taimikylvön lämpötilan odotetaan kohoavan korkeimmaksi, koska sen vähäinen kasvillisuus ei varjosta tai haihduta yhtä paljon. Korkean lämpötilan odotetaan nopeuttavan kosteuden poistumista kuivilla kausilla. Keskimääräinen vedenpidätyskyky oli hieman korkeampi taimikylvössä kuin muissa käsittelyissä. Kaikki käsittelyt pidättivät hyvin vettä verrattaessa kirjallisuuteen. Vedenpidätyskyvyn todettiin vähenevän sademäärän kasvaessa. Keskimääräistä suurempien sadetapahtumien (yli 7,3 mm) kohdalla vedenpidätyskyky vaihteli valmismattokatolla 19–97 % välillä, biohiilikatolla 33–98 % välillä ja taimikylvössä 22–99 % välillä. Keskimääräistä pienempien sadetapahtumien kohdalla vedenpidätyskyky puolestaan vaihteli valmismattokatolla 90–99 % välillä, biohiilikatolla 64–99 % välillä ja taimikylvössä 65–100 % välillä. Valuntamäärillä ei ollut tilastollisesti merkitseviä eroja käsittelyjen välillä. Suodosvesi valui nopeimmin taimikylvöstä ja hitaimmin biohiilikatosta. Biohiili siis hidasti valuntaa. Tilastollisia eroja valunnan kestoille ei löytynyt Kruskal-Wallisin testillä. Taimikylvön todettiin olevan yleensä kuivin käsittelyistä, mutta se myös vettyy nopeimmin. Taimikylvökatolla mitattiin käsittelyjen korkeimmat sekä matalimmat lämpötilat. Lähellä pintaa lämpötila vaihteli huomattavasti. Valmismaton ja biohiilikaton lämpötilat olivat tasaisempia, koska runsaampi kasvillisuus varjostaa ja eristää. Regressioanalyysin perusteella valmismatto- ja biohiilikattojen kosteuspitoisuus vaikutti merkitsevästi niiltä syntyvän valunnan määrään, kun sademäärä oli yli 7,3 mm, mutta ei pienemmillä sateilla. Sateen intensiteetti myös selitti kosteuspitoisuuden muutosta.
  • Kallio, Siina (2023)
    Ilmasto- ja ympäristötavoitteiden saavuttamiseksi Suomi on mukana Euroopan Unionin Vihreä siirtymä -hankkeessa. Vihreä siirtymä on monitulkintainen termi, joka saa poliittisissa keskusteluissa useita merkityksiä. Tutkielman tavoitteena on selkeyttää sitä, mistä kaikesta poliittisissa keskusteluissa puhutaan vihreän siirtymän yhteydessä. Lisäksi tutkielmassa paneudutaan siihen, minkälaisia merkityksiä vihreälle siirtymälle annetaan ja mitä siihen kytkeytyvällä retoriikalla pyritään perustelemaan. Tutkielmaa taustoitetaan vihreän siirtymän ja oikeudenmukaisuusperiaatteen historiallisella katsauksella, ja erilaisilla vihreän siirtymän ja oikeudenmukaisen siirtymän määritelmillä. Teoreettisena viitekehyksenä hyödynnetään ympäristöpoliittista diskurssianalyysiä, ja sen jälkeen esitellään ympäristön ja talouden välisen suhteen diskurssien ominaisuuksia tarkemmin. Aineisto koostui vuoden 2022 eduskunnan lähetekeskusteluista helmikuulta kesäkuuhun. Tutkimuksessa tarkasteltiin 73 vihreää siirtymää käsittelevää puheenvuoroa, joita analysoitiin laadullisen sisällönanalyysin avulla. Puheenvuoroja suhteutettiin Dryzekin (1997) ympäristödiskursseihin ja niistä muodostettiin lopulta yhteensä kuusi aineiston omaa diskurssilinjaa. Tuloksista tunnistettiin, että vihreä siirtymä kontekstualisoitiin diskursseissa 1) muutoksen, 2) talouden, 3) uhan ja 4) mahdollisuuden kautta. Lisäksi vihreään siirtymään yhdistetyiksi teemoiksi nousivat oikeudenmukaisuus ja tulevaisuuden varmistaminen. Teemojen valossa vihreään siirtymään suhtauduttiin hyvin polarisoituneesti, joko kannattaen tai vastustaen sitä. Lisäksi diskursseihin sisältyi vahva talouden läsnäolo, joka välittyi ekologisen modernisaation periaatteen laajana hyväksymisenä ja uusliberalistisen retoriikan käyttönä. Vaikka vihreän siirtymän toimet ovat kestävyyssiirtymän mukaisia vaikuttaa kuitenkin siltä, että siirtymän vaikutukset kuvataan diskursseissa kestävyysmurroksen kaltaisina.
  • Heikkilä, Sami (2019)
    Viruses are a functional part of the water ecosystems microbial network. There is scientific evidence that viruses have impact to biotic communities, nutrient recycle and genetic diversity. Still there is a lack of studies concerning fresh water ecosystem viruses. In Finland, studies of fresh water viruses have not been published. Main objective of this thesis was to study, first time in Finland, abundance and variation of virus like particles (VLP) in boreal lake. The study was carried out on Lake Vesijärvi in Southern Finland. Purpose was also to study the abundance relations of VLP to bacterial abundance and algae biomass. Temporal changes of the variables were studied in 4 periods during growing season in 2007 and 2 periods during winter season in 2008. Spatial changes of variables were studied in littoral and pelagic zones in early summer 2007. Abundance of VLP was high in productive layer (11,9 ± 0,7 x 107 (ml-1)). Similar results have been observed from studies with other lakes in boreal zone. Highest abundance observed was in early summer period (14,9 ± 0,2 x 107 (ml-1)) and lowest at the end of the winter season period (5,5 ± 1,3 x 107 (ml-1)). High bacteria abundance and algae biomass with suitable physical and chemical conditions were the main reasons for high VLP abundance. In the growing season an average amount of chlorophyll –a was 8,6 μgl-1. In the winter season a very high amount of chlorophyll –a was observed (22,4 ± 1,2 μgl-1) indicating under ice algal bloom. Bacteria abundance was stable during the growing season (1,3 x 107 ml-1) corresponding to findings with earlier studies on Lake Vesijärvi. Virus / bacteria ratio (VBR) –level varied between 7,5 – 25,3 in the growing season and in the winter season between 1,6 - 9,3. Bacterial abundance growth explained 18,2 % of the growth of the VLP abundance (p=0,004, all periods included). In the growing season chlorophyll –a explained 17,4 % of the growth of the VLP abundance (p=0,013). In the winter season, connections between VLP and other biological variables were not found. As a conclusion, in the growing season algae cells (Inc. cyanobacteria) are dominant hosts for viruses. Dominant host probably varies between the seasons. Between littoral ja pelagic zones, differences of abundance of VLP, bacteria and algae biomass were not found. This was probably caused by windy conditions creating similar conditions between zones. There is a high abundance of viruses in productive layer in Lake Vesijärvi year-round. Viruses have direct and indirect interactions with algae and bacteria varying in different time scales. It is likely that viruses have interactions also with other functional groups of the lake microbial network. The results of this study confirmed, for the first time in Finland, the virus abundance, its variation and interactions with functional groups of microbial network. The role of viruses in biochemical cycles of fresh water ecosystems need to study more in Finland.
  • Holopainen, Katariina (2023)
    At visual threshold, the vision relies on catching incident photons. The ultimate limitation of visual sensitivity arises from the quantal nature of light. At night, the uncertainty of photon arrivals differs fundamentally from daylight conditions, where photon flow can be considered continuous, and sets an absolute physical limitation to visual sensitivity. Visual sensitivity has been postulated to be affected by circadian physiological changes. Here, we have shown, that absolute visual sensitivity is under circadian control in light decrement, or quantal shadow, detection in mice. A behavioural visual task of finding a dark stimulus spot was conducted in a white water maze across several background light intensities leading gradually from clearly visible light to darkness. The percentage of correct choices in the task as a function of light intensity was used to measure visual sensitivity, which was remarkably higher nocturnally. Another parameter affecting visual sensitivity was shown to be the decrement size. Mice were more successful in finding the bigger decrements of the three spatial scales used, as well as succeeding in the task better at night. This finding suggests that visual sensitivity is affected by the absolute number of photons, or more precisely, the absolute number of missing photons in contrast to photons of the background illumination.
  • Lallukka, Niina (2018)
    Pohjavesien pilaantuminen on merkittävä ympäristöongelma. Esimerkiksi jotkut haihtuvat orgaaniset yhdisteet (VOC), kuten metyyli-tert-butyylieetteri (MTBE) sekä trikloorietyleeni (TCE), ovat saastuttaneet laajojakin pohjavesialueita. Pohjavesien kunnostuksessa ongelmana on, että nykyisillä menetelmillä pohjavettä on vaikeaa ja kallista puhdistaa. Perinteisessä pump & treat –menetelmässä vesi pumpataan maan päälle puhdistettavaksi, ilman että vuosienkaan jälkeen pitoisuudet välttämättä laskevat merkittävästi. Air sparging on edullisempi ja nopeampi menetelmä, mutta menetelmän soveltuvuus on tapauskohtaista. Myös kemiallinen hapetus on kohdespesifinen ja siksi toimivuudeltaan epävarma menetelmä. Näin ollen uusille puhdistustekniikoille on todellista tarvetta. Yksi mahdollinen vaihtoehto voisi olla uusi vetyperoksidin kuplitus -menetelmä, joka perustuu vetyperoksidin (H2O2) hajoamisreaktioiden kykyyn mobilisoida ja haihduttaa pohjavedessä sijaitsevia VOC-aineita. Pohjavesikerrokseen korkeana pitoisuutena syötetty H2O2 leviää ja luonnostaan esiintyvä rauta katalysoi sen hajoamista. Hajoamisreaktioiden käynnistyessä vapautuvan kaasun oletetaan johtavan ilmastuksen ja strippauksen kaltaisiin vaikutuksiin, johtaen VOC-yhdisteiden haihtumiseen. Etuna ilmastukseen verrattuna olisi se, että vaikutussäde olisi nestettä lisäämällä mahdollista saada suuremmaksi kuin ilmaa syöttämällä. Vaikka käytetyt reagenssit ovat samoja kuin kemiallisessa hapetuksessa, toimintaperiaatteen takia menetelmän ei uskota olevan yhtä kohderiippuvainen. Tässä pro gradu –tutkielmassa selvitettiin vetyperoksidin kuplitus –menetelmän soveltuvuutta VOC-yhdisteiden poistamiseen pohjavedestä. Tutkielma koostui laboratorio-, lysimetri- ja kenttäkokeista. Laboratoriokokeissa selvitettiin menetelmän soveltuvuutta ominaisuuksiltaan erilaisille VOC-yhdisteille. Lisäksi selvitettiin, miten eri muuttujat (H2O2- ja rautakonsentraatio sekä kelaattilisäys) vaikuttavat H2O2:n hajoamisreaktioaikaan sekä MTBE:n poistumaan. Pilot-mittakaavan lysimetrikokeissa testattiin MTBE:n poistamista sekä pelkästä vesifaasista että hiekkamaasta. Kokeissa käytettiin bensiini- ja TCE-saastunutta vettä sekä keinotekoista MTBE-vettä, jonka pitoisuus oli 750 mg/l. Menetelmän toimivuutta täydessä mittakaavassa testattiin entisellä polttoaineiden jakeluasemalla yhdessä Nordic Envicon oy:n kanssa. Laboratoriokokeissa sekä pilot-kokeen vesikokeessa saavutettiin lähes 100 %:n puhdistumistulos. Pilot-vaiheen hiekkakokeessa MTBE:n poistuma oli noin 94 % ja toistetulla käsittelyllä lähes 97 %, mutta seisotuksen myötä pitoisuudet nousivat, jolloin poistuma jäi 85 ja 66 prosenttiin. Kenttäkokeessa vetyperoksidin havaittiin levinneen koko koealueelle, mutta epätasaisesti. Puhdistumista tapahtui alueella, jonne vetyperoksidia oli levinnyt eniten, ja jossa pitoisuuden oletettiin olleen riittävä tutkitun vaikutuksen aikaansaamiseksi. BTEX- ja bensiinijakeiden pitoisuudet laskivat muutamassa kuukaudessa jopa 88–97 %. Vaikka pitoisuuksien laskun kannalta kokeet olivat onnistuneita, ei vetyperoksidin kuplitus -menetelmää pystytty hypoteesien vastaisesti erottamaan kemiallisesta hapetuksesta. Sen sijaan hapettumista sekä haihtumista tapahtuu tulosten perusteella samanaikaisesti. Täyden mittakaavan sovellutuksia varten menetelmää onkin tarpeen vielä tutkia ja optimoida esimerkiksi massatasapainokokeiden avulla.
  • Jokelainen, Antti (2023)
    The Arctic region is experiencing an intensification in the hydrological cycle due to climate change. Lakes in the Arctic respond quickly to environmental changes and act as archives to past climates. Naturally occurring stable isotopes of water, specifically the isotopes of oxygen and hydrogen, provide a valuable tool for investigating local hydrological conditions and reconstructing past climates. In this study, stable isotopes of water in Värriö, Northeastern Finland, were analyzed to gain insights into the local hydrology and assess the use of palaeoclimatological methods for reconstructing past climates. Precipitation, groundwater, and lake water were analyzed to characterize the local isotope hydrology. To assess the reconstruction of past climate conditions, a set of modern chironomid head capsules were collected and analyzed for their isotopic composition. Chironomid head capsules are commonly used to reconstruct past climate conditions. The results indicated that precipitation in Värriö is sourced from the Barents Sea to a considerable extent, which has implications for the isotopic composition of surface waters. The isotopic composition of lake water in Kuutsjärvi was found to reflect the precipitation isotopic composition well due to a lack of evaporative enrichment. The study also noted the seasonal effects of spring thaw on the lake, and the contribution of groundwater as a controller of these effects. The analysis of chironomid head capsules in this study yielded values that differed from present-day conditions. The possible reason for the offset in values was explored, but not identified. This highlights the importance of accurate calibration of chironomid head capsule values and knowledge of chironomid ecology when using this method for palaeoclimatological research. Overall, this study demonstrates the utility of stable isotopes of water for characterizing local hydrological conditions and reconstructing past climates.
  • Stuart, Elliot (2013)
    The primary characteristic of urbanisation is the addition of hard surfaces to catchments, which affects water and habitat quality in urban streams and alters natural hydrological processes by reducing infiltration, evapotranpiration and efficiently conveying storm runoff to streams, gathering a variety of urban polluants along the way. This is typical of the 'urban stream syndrome'. Catchment imperviousness (especially Effective Impervious Area or percent connectivity) can be used as one of the primary indicators of the severity of this phenomenon. This research was initiated through a collaboration between the City of Helsinki and the University of Helsinki to determine the baseline water quality of Hakuninmaanoja, a small urban stream in Helsinki, Finland, and the imperviousness of its catchment, where a pilot ecological housing development 'Kuninkaantammi' (KUNTA) will be built beginning in 2013. The purpose of the project is to assess the current characteristics of the catchment prior to the development in the headwaters of the stream. An automatic water quality monitoring station was built on the lower part of the stream approximately 200m upstream of its junction with Mätäjoki, the second largest river of Helsinki. Water Sensitive Urban Design can be used as part of a holistic stormwater treatment train to limit newly created imperviousness, and minimise the connectivity of the necessary remainder, allowing stormwater runoff to be reused, infiltrated and treated through soil media, or slowed down enough to attenuate the urban hydrograph. Some of these features such as raingardens, green roofs and detention ponds will be included in the KUNTA development for this purpose. A detailed calculation of catchment imperviousness was completed via field survey and land use categorization methods. Total Impervious Area (TIA) was determined to be 22%, Effective Impervious Area 15% and catchment wide runoff coefficient given by land use categorisation method to be 0.32. TIA is expected to increase to 30% following development of KUNTA, however EIA is not expected to increase in proportion with TIA due to planned Water Sensitive Urban Design features. Yearly runoff volumes based on each method of calculating imperviousness were estimated, as well as for the future following KUNTA development. Water quality in the stream currently is quite satisfactory in relation to other streams in Helsinki, however the urban stream syndrome is already evident with particular concern regarding temperature, sediment and peak flow fluctuations. Effective Impervious Area should be used in urban planning of new and existing developments rather than TIA because it will give much greater accuracy of runoff volumes and infiltration rates by taking into account unconnected impervious surfaces. Strengthening local solutions to reduce connectivity should be a municipal priority. Water quality monitoring will continue at the site until after KUNTA has been built, and further research should focus on determining the technical performance of stormwater Best Management Practices (BMPs) at the site.
  • Silvennoinen, Emmi (2015)
    Infiltration rates in urban areas are low due to a high proportion of impervious structures. Impermeability results in increased rates of urban runoff, which often leads to degradation in receiving waters. Stormwater retention in urban areas can be increased, for instance, with green, vegetated roofs. While impervious, normal roofs produce the runoff immediately, studies with green roofs have shown that they cause delays in peak runoff and reduce the runoff rate and volume by water retention and attenuation. The water retaining capacity of green roofs vary due to local weather conditions and roof characteristics. Several studies and experiments considering stormwater management and other ecosystem services that green roofs provide have been performed worldwide, mainly in temperate regions, while more studies are needed in cold climates especially to quantify the performance of green roofs in winter. The purpose of this thesis was to evaluate the effects of various types of precipitation events on runoff rates, timing and water retention in locally built new green roofs from late summer to early winter in southern Finland. Data on precipitation and green roof runoff as well as soil temperature and humidity were monitored automatically. Green roofs included a) precultivated readymade vegetation mats and b) built on site novel substrate mixture with plug plants and seedlings. My principal aim was to study the capability of green roofs in retaining and attenuating water in relation to the intensity and duration of precipitation, the length of the antecedent dry weather period as well as to temperature and moisture of the green roof substrate. I hypothesised that green roofs retain low intensity events better than high intensity events and more effectively in dry and warm than in wet and cold weather, being negligible at temperatures below 0 °C. Furthermore, I studied whether retention capacity can be improved by the amendment of biochar. Finally, readymade green roofs with dense vegetation was hypothesised to have better retention capacity than the newly created roofs with very sparse vegetation but only in summer due to evaporation. Based on cumulative runoff, green roofs retained 52 % of rainfall, which is close to the retention capability found in previous studies. Retention was generally higher at warm temperatures and for biochar-amended roofs, in agreement with my hypothesis. Against expectations, roofs with readymade vegetation mats had lower retention than those built on site. In summer and autumn, before freezing temperatures occurred, results were generally according to the hypotheses and previous research: retention rates decreased as rain depth or rain peak intensity increased. When the amount of rain preceding the measurement event was low, and the substrate moisture content was low, retention was better. During wintertime, results were contrary to my hypotheses: Total retention rates increased with the amount of rain and rain intensity, or when substrate moisture content increased. However, a long antecedent dry weather period resulted in better retention, especially during winter. Mean peak flow attenuation for rain events in this study was 64 % and results are in accordance with my hypothesis and previous research. Furthermore, delay times from when the rain event started to when runoff started and from rain peak to runoff peak were detected in this study, mean values of more than 1 h being comparable to what has been reported in the literature. Results from my thesis can be used to improve hydrological models for local stormwater management purposes. Furthermore, results can be compared with those of other ecological stormwater treatment methods. Possible future research topics include the functioning of green roofs during different seasons and especially during freezing and melting periods with assumedly complex hydrological interactions.
  • Nuorivaara, Essi (2021)
    In recent years, the role of economic models in guiding government policy has provoked discussion as human wellbeing and the state of the environment are threatened by multiple sustainability challenges, most notably by the ecological sustainability crisis. The mainstream economic approach has received criticism since it has not been able to solve these challenges and thus, several alternative approaches in pursuit for a just and sustainable future have gained popularity both nationally and internationally. In this thesis I focus on the wellbeing economy concept in the Finnish welfare state in the early 2020s. Wellbeing economy was introduced in Finland by the Finnish Federation for Social Affairs and Wealth (SOSTE) in 2012 to highlight the interdependency of human wellbeing and economy. The concept has since been developed and realized by different actors of the society, but it is not yet that well-known among the public. To find out the potential role of this new economic approach in the transition towards sustainable welfare society, it is important to get a clear picture of how the concept is interpreted by its advocates. Therefore, in my case study, I examined the expert narratives of wellbeing economy. My main research question is: What does the concept of wellbeing economy mean in Finland in the early 2020s? This question is complemented by two sub-questions: 1) What are the shared contents and practices associated with wellbeing economy? and 2) What are the key differences between different conceptions of wellbeing economy? The underlying disagreements in theory and in practice of wellbeing economy might impact the integrity of the concept even if the concept formulation of wellbeing economy seems consistent. I conducted seven (7) semi-structured expert interviews from five (5) different organizations during the spring 2021. The interviews were thematically analysed with a focus on the memes of neoliberal narratives and the memes of alternative narratives as well as the conflicting memes in alternative narratives. In this study, a meme is defined as the structural component of a narrative. Finally, I identified similarities and differences in these building blocks of wellbeing economy narratives between different experts. I found that there were more shared memes than differences in the experts’ conceptions of wellbeing economy. Most of the interviewees mentioned memes of neoliberal narrative. All the interviewees mentioned the alternative narrative memes connected networks, sustainability, cooperation with others, and human dignity, prosperity, and wellbeing. Most of them also considered the Covid-19 pandemic as an opportunity in crisis. However, the meme a new economic system created the greatest division in the interpretations of wellbeing economy. In conclusion, some interviewees supported the neoliberalism more clearly while others opposed this narrative, and the rest were not clearly for or against the growth-agenda. The ambiguity of the concept especially in terms of economic growth should be further discussed in addition to specifying, for instance, what is meant by sustainability and wellbeing in wellbeing economy. Further research is also needed to find out how the discussion about wellbeing economy concept will develop in Finland and internationally.
  • Serra Dominguez, Lluis (2021)
    Beta diversity (total dissimilarity) can be partitioned into two components: dissimilarity attributed to turnover and nestedness-resultant dissimilarity. Turnover refers to the variation in species identities among sites and implies the replacement of some species by others. In contrast, nestedness occurs when species-poor sites have a subset of the biota present in species-richer sites. Although disentangling the relative contribution of these two antithetic components from beta diversity can characterize species assemblages, the dissimilarity indices do not provide information on the processes generating the patterns. Conversely, Hierarchical Modelling of Species Communities (HMSC), which unifies many of the recent advantages of Joint Species Distribution Models, has proved to be the one of the best performing frameworks for unravelling the underlying mechanisms structuring ecological communities. The aim of this research is to explore the relationship between the outputs of the HMSC model and the dissimilarity indices in different communities with a wide range of parameterizations. As the observed patterns measured by the beta-diversity indices result from the underlying processes which HMSC attempts to capture, I hypothesized that both frameworks are at least partially linked to each other. To achieve this aim, I simulated the community data by following the structure of the HMSC model. For simplicity, only one environmental covariate was considered, which was scaled to 0 mean. The intercept of the HMSC model accounted for the baseline occurrence probability of the species, while the slope modeled the species responses to the environmental covariate. The HMSC-intercept and the HMSC-slope, which represent the species multivariate niches, were summarized in terms of center and spread. Simultaneously, the beta diversity indices (total, turnover and nestedness dissimilarity) were calculated from the community data. Finally, the outputs of both frameworks were related in terms of linear modelling and variation partitioning. As hypothesized, the results of this study suggest that outputs of the HMSC model are able to explain most of the variation in the beta-diversity indices, indicating that both frameworks are strongly related. By plotting the species niches (intercept and slope coefficients of the HMSC model) it is possible to determine the main axes of niche variation producing the nestedness and turnover patterns. While nestedness is generated by a shared response of the species to the environmental covariate(s), turnover is produced by variation in the species responses. Finally, the total dissimilarity index is driven by species rarity. In conclusion, the most comprehensive evaluation of the structure of ecological communities and the processes determining the diversity patterns can be achieved by combining the outputs of beta-diversity indices and the HMSC model.
  • Carlson, Helmi (2021)
    Tiivistelmä Referat – Abstract One of the major fundamental ecological questions is the composition of a species diet. The diet of a species is crucially linked to finding out its environmental requirements, and information about the possible changes in the diet is needed when studying the impact of environmental changes such as climate change on species. Siberian flying squirrel (Pteromys volans), classified as endangered in Finland, is a species living in coniferous and mixed forests. More precise information about the dietary habits of the species is needed to support conservation. The aim of my thesis was to investigate the diet composition and diet diversity of adult flying squirrels using DNA barcoding of their excrement pellets, a technique that provides highly accurate information quickly and effectively. The main research questions were whether the diet varies between sexes and seasons, whether diet has an influence on body condition and breeding success of the females, and whether diet diversity is related to the amount of suitable forest habitat near the nests. We collected faecal samples from 51 different flying squirrel individuals from two different study areas near the cities of Vaasa and Pietarsaari in June of 2020. Another set of samples from 8 individuals was collected in November 2020 in Vaasa. The collected samples were sent to a laboratory in Turku, where the DNA barcoding was conducted. I then made further statistical analyses from the laboratory results using general linear models to test my study questions. Although the sample size was too small to obtain statistically significant results for all the research questions, my results indicated that the diet of the Siberian flying squirrel differs between males and females just like its other living habits. Male flying squirrels have more diverse diet than female flying squirrels which have more specific and narrow diet, as they also have smaller home ranges during the breeding season and are more linked to their nesting forest patch compared to males. The aspect that female flying squirrels are more specialists during breeding time is crucial for the species conservation planning. DNA barcoding studies with bigger sample sizes should be done to further investigate the relationship between diet diversity and individual’s body condition and to ascertain the statistical significance to the results of this study.
  • Rautjärvi, Sini (2022)
    Urbanization is a growing trend, with most people living in cities nowadays. Understanding the relationships between people and nature is crucial, as ecological conditions are heavily influenced by human-environment interactions. According to prior research, socioeconomy and biodiversity are generally related. Low biodiversity typically correlates with poorer socioeconomic status, and vice versa. In this study, I aimed to determine whether there is a correlation between Lahti's socioeconomy (income) and biodiversity (bird and plant species richness and the urban ecosystem integrity index, UEII). Lahti is a medium sized city with an urban continuum of 54 km2. I used existing biodiversity data collected in the summer of 2021 and combined it with the most up-to-date socioeconomic data at the time, retrieved from the publicly available city of Lahti statistical database TILDA. The results of the study were contradictory to previous research, i.e., there was no relationship between biodiversity and socioeconomy. This gives us novel information about the luxury effect and its presence and opens doors for further research on the topic.
  • Eriksson, Julia (2023)
    Inflammatory bowel disease (IBD) is a chronic autoimmune disease, with recurring inflammation in the gastrointestinal tract. Although the actual cause of the disease is still unknown, many molecular and underlying pathways have been discovered. Infliximab (IFX) is an effective and safe antibody medication that specifically targets the cytokine protein TNF-α. This medication is given to IBD patients who do not respond to other conventional drugs and who face the final step of surgery. However, around 30 % of IBD patients do not respond to this medication at all and another 50 % either lose the effect over time, or need to discontinue the medication due to severe side effects. Therefore, it would be important to find a biomarker that could predict the outcome of the medication. In this study, 73 IBD patients have given blood samples both before and three months after the start of IFX medication. From these blood samples the RNA was extracted and sequenced to get the transcriptome profiles. The aim of this study is to find novel biomarkers, that could be used as a predictive tool for the outcome of the medication. Seven significantly differentially expressed genes were found before IFX treatment initiation between responders and non-responders of the medication. Additionally, a clear effect from the IFX medication was seen in the transcriptome profiles.
  • Niskanen, Ville-Pekka (2021)
    This Master’s thesis is two-part. The first part is the Methodological Introduction, which introduces the background of this research, the research process, methods and ethical considerations. The second part is a manuscript of a scientific article, sent for review in the scientific journal Sage Open, with the title Wicked problems in Africa – A systematic literature review. The article is a systematic literature review of the usage of Horst W. J. Rittel and Melvin M. Webber’s wicked problems concept in peer-reviewed scientific literature focusing on Africa. The reviewed 45 scientific articles were chosen using a systematic methdolology, basing on a set of inclusion criteria. Based on the reviewed literature, three research questions were answered by utilizing the tabulation of key information from the articles, and with content analysis. The research questions are: 1) What are the main themes and concrete manifestations of issues descri-bed as wicked in the African context? 2) What are the geographic foci of articles that use the concept of wicked problems in the African context? 3) Is the concept of wicked problems utilized and therefore seen as applicable by authors affiliated with African cultures? Based on the reviewed articles, a typology is formed. According to this typology, wicked problems in the African context can be interlinked, exacerbated, or contextual. Especially important is the contextuality, which the concept of dual wickedness reminds us of. In addition, the research states that the lack of usage of the wicked problems concept in scientific literature on Africa may be because of the English-language or Western background of the concept. Based on the results, we suggest, that future characterizations of the wicked problems concept should include context-sensitivity.
  • Lakso, Mea (2022)
    Knowledge co-production has become increasingly popular and even ‘buzzed’ notion in sustainability sciences. It is being applied in various contexts and for myriad of purposes under different, even partially contradicting rationales, yet it is often expected to contribute better to the sustainable transformation of society than normal science. One of the uniting elements in different understandings and applications of ‘knowledge co-production’ is the involvement of the extra-scientific actors in the research process. This implies changes in the conventional roles and relationship between science and society, that raise new questions about the autonomy and accountability of science. This master’s thesis studies knowledge co-production in higher education context and, more specifically, in the case of the HELSUS Co-Creation lab 2019-2020, and critically explores the notion of co-production in sustainability sciences. The dynamics, relationship, and roles between the scientific and extra-scientific actors within the Co-Creation lab are the specific interest in this qualitative case study that is primarily based on 12 semi-structured interviews of the lab participants analyzed by qualitative content analysis. The study shows how the dynamics between the master’s level students and the partners from the private and public sectors had features that resembled to some extent commissioned research type of roles, task coordination and interdependencies, however, it also contained significant characteristics that distinguished it from pure commission type of dynamics, as the autonomy of the student was greater, the control of the partner over the knowledge production process was lesser and the accountability of the students to the partners was more indirect and softer. The similarities between the application of knowledge co-production in the HELSUS Co-Creation lab and the co-production by the logic of accountability are highlighted and critical questions concerning instrumental forms of co-production, logic of accountability, usefulness of knowledge and scientific autonomy are discussed. More critically reflective approaches towards co-production are called for.