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Browsing by Subject "environmental change"

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  • Mickos, Kasper (2024)
    Itämeri ja Suomenlahti ovat voimakkaan ihmisvaikutuksen alaisena, mikä on aiheuttanut suuria muutoksia monissa kalapopulaatioissa. Tästä huolimatta tieto rantavyöhykkeen kalaston tilasta näissä olosuhteissa on vähäistä ja paikoittaista: tietoa niiden pitkän ajan kehityksestä 2000-luvun Itämeressä ei ole. Tutkin touko-syyskuussa 2023 rantavyöhykkeen kalastoa poikasnuottaamalla Hangon Tvärminnessä, läntisellä Suomenlahdella. Selvitin kalojen runsauden alueella laskemalla sekä kalojen määrän pyyntiponnistusta kohti että kalaston yksilötiheyden. Kartoitin kalaston lajikoostumuksen laskemalla lajien suhteelliset runsaudet, sekä laskemalla ajallisia ja alueellisia diversiteetti-indeksejä. Vuodenaikaisvaihtelua selvitin vertailemalla kuukausittaisia saaliita, sekä arvioimalla poikasten määrän ajallista vaihtelua. Vertailemalla tuloksiani tietoihin vuodelta 1992 tutkin kalastossa tapahtuneita pitkän ajan muutoksia. Kalojen runsaus romahti yli 90 % vuodesta 1992 vuoteen 2023. Yksilömäärän lasku koski lähes kaikkia lajeja, ollen rajoittumatta sellaisiin, jotka suosivat tiettyjä ympäristön olosuhteita. Vuoden 2023 saaliissa oli kolme uutta lajia, kun taas kymmentä vuonna 1992 esiintynyttä taksonia ei havaittu. Runsaimmat lajit 2023 olivat kolmipiikki (Gasterosteus aculeatus L., 1758), salakka (Alburnus alburnus L., 1758), liejutokko (Pomatoschistus microps Krøyer, 1838) ja hietatokko (Pomatoschistus minutus Pallas, 1770), jotka muodostivat yli 90 % saaliista. Silakka (Clupea harengus membras L., 1761), kilohaili (Sprattus sprattus L., 1758) ja ahven (Perca fluviatilis L., 1758) olivat erittäin runsaita 1992 mutta erittäin harvassa 2023, kun salakan määrä taas kasvoi yli kaksikymmenkertaisesti. Poikasten ilmaantuminen runsaissa määrin tapahtui kuukautta myöhemmin vuonna 2023, todennäköisesti johtuen kylmemmistä alkukesän lämpötiloista. Kalamäärän romahdus on todennäköisesti seurausta sekä vuosittaisesta poikasmäärän vaihtelusta että kalojen vähenemisestä pitkällä aikavälillä. Silakan, kilohailin ja ahvenen vähäiset määrät johtuvat todennäköisesti poikasmäärän vuosittaisvaihtelusta, joskin tämän varmistaminen vaatii vuosittaisia mittauksia. Salakan määrän runsas kasvu viittaa rehevöitymisen ja vesien lämpenemisen vaikutukseen. Tulokseni korostavat tähän mennessä huonosti tunnettujen pitkän ajan muutosten laajuutta Itämeren rantavyöhykkeen kalastossa.
  • Saarni, Matti (2019)
    Climate change affects the human habitat and the mechanics that cause this scientific phenomenon are somewhat well known. This study examines how forest policy, agricultural policy and environmental policy can control the mechanisms that cause climate change. The material of the study consists of interviews of 12-13 Finnish experts, each representing one of the previously mentioned sectors. Each of the experts have been asked 13-14 questions about the importance of climate change mitigation, as well as the mechanisms by which agriculture and forests affect the climate and how climate change should be considered in environmental policy. The data was collected between October 8th and November 8th of 2019. This was in five weeks after the IPCC 1,5-degree climate report was published. A series of topics was constructed from the answers, and they are meant to be used as topics to be discussed in the Finnish 2019 parliamentary election. In addition, on how important scientific academics see the control of climate change, they were also asked how critical climate change is. The interview material is stored in the Finnish Social Science Data Archive (www.fsd.uta.fi) The experts’ answers to the importance of controlling climate change were almost unanimous and considered to be highly important. Carbon sink and storage were considered the most effective methods to control climate change. According to the results, the study proposes topics that should be discussed in politics and when a person wants to advance the control of climate change in forest, agriculture and environment politics. Political decisions are often based on value judgement, which again are based on the information of different methods efficacy. The results that are discussed in this study are not the only options, but they give guidelines and reasons for discussions related to effective choices. Forest policies should recognize the effects of forest industry to the development of carbon sink and storage. Forest industries prerequisite for operation and decision making in addition to considering employment and export industry, must also consider the effect for Finland’s net carbon emissions. Activities which lengthen the forest rotation time would have multiple positive benefits and increase forest carbon storage. Agricultural politics should broaden the discussion to reach food politics. Consumption habits have big effect on agricultural production structure and it can be directed by many ways. The structure of agricultural production should also be considered from the emission point of view, because the land use is substantially large and changes in production can affect Finland’s emission in a scale, that would have large effect on our nations net carbon emissions. To strengthen carbon sinks, landowners should have compensation mechanism methods, that increase carbon sinks, and which are combined to the size of the carbon storage. In environmental policy climate change must be paid more attention and governmental boundaries must not intervene significant decision making. The strengthening of the role of Ministry of the Environment and adding co-operation between different ministries supports the decision making regarding environmentally positive issues.
  • Atti, Sanna (2021)
    Underwater light climate in mountain lakes is controlled by dissolved organic carbon concentrations and by lake ice regimes. Both are affected by local, regional and global variables linked to anthropogenic disturbances such as climate change and atmospheric pollution. Aim of this work was to investigate changes in underwater light climate over the past ~200 years in two oligotrophic mountain lakes and how it reflects on diatom (Bacillariophyceae) guild distribution. For these aims, diatom communities and ecological guilds were analyzed from sediment core and contemporary habitat samples along a depth gradient. In addition, sediment inferred chlorophyll a (CHLa) and lake water total organic carbon (TOC) were analyzed to detect development of primary production and lake water carbon content. Results showed that acidification of the lakes together with climate induced changes have been important drivers of the ecology of the lakes. Lake water TOC showed a decline and subsequent increase in line with the acidification and subsequent recovery of the lakes, likely affecting underwater light climate in the lakes. However, this did not reflect unambiguously into changes in diatom functionality. Warming has likely contributed to diversification of the diatom community over the study period while no distinct increases were observed in whole lake primary production. Overall, if the present study could not distinguish the exact role of underwater light in driving changes in diatom communities and functional traits, the result show that human pressures have left distinct imprints in the development of biotic communities in these remote mountain lakes.
  • 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.