Amazonin guadua-bambujen fytoliitit ja niiden käyttö biogeografisessa tutkimuksessa

Fytoliittitutkimus on arkeologian ja arkeobotaniikan tutkimusmenetelmä, jolla on useita eri sovellusmahdollisuuksia eri tieteenaloilla. Fytoliitit syntyvät kasvin soluihin ja soluväleihin nestemäisen piidioksidin (SiO2) kovettuessa ja muodostaessa ikään kuin mikroskooppisia kiviä, jotka mukailevat kasvin rakenteiden muotoja. Koska fytoliitit ovat valoksia tuottajakasvinsa rakenteista, voidaan maaperästä tai arkeologisista kaivauksista löytyneistä fytoliiteista tunnistaa alueen kasvillisuutta. Fytoliittien avulla voimme luoda paleoympäristön mallinnuksia tai esimerkiksi tunnistaa historiallisista ruukuista mitä kasvia niissä on säilytetty tuhansia vuosia sitten. Tämän tiedon avulla voimme tehdä päätelmiä eri aikakausien ravintokasveista tai jopa mahdollisesti päätellä onko kasvi domestikoitu vai alkuperäiskasvi. Tutkimukseni tavoitteet olivat selvittää Amazonin alueen Guadua-suvun bambujen tyypillistä fytoliittijakaumaa ja selvittää alueellisia eroja tutkimusalueideni välillä. Erotin fytoliitteja bambunlehtinäytteistä sekä maaperänäytteistä, kolmesta eri syvyydestä. Bambunlehtinäytteissä käytin fytoliittien erotukseen polttomenetelmää, joka mahdollisti fytoliittien sijoittumisen tarkastelun lehden rakenteissa. Maaperänäytteisiin käytin märkäuuttomenetelmää, jossa fytoliitit erotettiin kemiallisesti uuttaen ja raskasnesteflotaatiolla. Lehtinäytteiden perusteella bambuille ominaisimmiksi fytoliittityypeiksi nousivat satula- ja bulliformfytoliitit. Maaperänäytteistä oli mahdollista löytää niin alueellista kuin syvyyssuunnassakin tapahtuvaa vaihtelua. Bambuihin viittaavien satulafytoliittien prosentuaalinen osuus oli bambualueilla suurempi kuin niiden ulkopuolelta kerätyissä näytteissä ja erityisesti Brasilian näytteissä satulafytoliitit olivat vähäisiä. Perun bambualueiden vierestä kerätyissä näytteissä satulafytoliittien määrä oli bambualueita vähäisempi, mutta kuitenkin runsaampi kuin Brasilian näytteissä. Tämä vahvistaa teoriaa siitä, että bambufytoliitteja voidaan käyttää tunnistamaan bambualueita maaperänäytteiden perusteella ja etäisyys nykyisistä bambualueista vaikuttaa satulafytoliittien määrään. Tutkimukseni tulokset tukivat aikaisempaa kirjallisuutta aiheesta, mutta tutkimuksen metodiikka vaatii vielä kehittämistä. Fytoliittien tunnistaminen oli osasta näytteistä haastavaa ja hyvän referenssiaineiston puuttuminen voi vaikuttaa tutkimuksen luotettavuuteen. Fytoliittitukimus avaa kuitenkin paljon uusia mahdollisuuksia biogeografiselle tutkimukselle ja tulee varmasti nousemaan tulevaisuudessa yhä suositummaksi menetelmäksi

Bioaerosols in the atmosphere at two sites in Northern Europe in spring 2021: Outline of an experimental campaign

A coordinated observational and modelling campaign targeting biogenic aerosols in the air was performed during spring 2021 at two locations in Northern Europe: Helsinki (Finland) and Siauliai (Lithuania), approximately 500 km from each other in north-south direction. The campaign started on March 1, 2021 in Siauliai (12 March in Helsinki) and continued till mid-May in Siauliai (end of May in Helsinki), thus recording the transition of the atmospheric biogenic aerosols profile from winter to summer.The observations included a variety of samplers working on different principles. The core of the program was based on 2- and 2.4--hourly sampling in Helsinki and Siauliai, respectively, with sticky slides (Hirst 24-h trap in Helsinki, Rapid-E slides in Siauliai). The slides were subsequently processed extracting the DNA from the collected aerosols, which was further sequenced using the 3-rd generation sequencing technology. The core sampling was accompanied with daily and daytime sampling using standard filter collectors. The hourly aerosol concentrations at the Helsinki monitoring site were obtained with a Poleno flow cytometer, which could recognize some of the aerosol types.The sampling campaign was supported by numerical modelling. For every sample, SILAM model was applied to calculate its footprint and to predict anthropogenic and natural aerosol concentrations, at both observation sites.The first results confirmed the feasibility of the DNA collection by the applied techniques: all but one delivered sufficient amount of DNA for the following analysis, in over 40% of the cases sufficient for direct DNA sequencing without the PCR step. A substantial variability of the DNA yield has been noticed, generally not following the diurnal variations of the total-aerosol concentrations, which themselves showed variability not related to daytime. An expected upward trend of the biological material amount towards summer was observed but the day-to-day variability was large.The campaign DNA analysis produced the first high-resolution dataset of bioaerosol composition in the North-European spring. It also highlighted the deficiency of generic DNA databases in applications to atmospheric biota: about 40% of samples were not identified with standard bioinformatic methods.</p

Bioaerosols in the atmosphere at two sites in Northern Europe in spring 2021 : Outline of an experimental campaign

A coordinated observational and modelling campaign targeting biogenic aerosols in the air was performed during spring 2021 at two locations in Northern Europe: Helsinki (Finland) and Siauliai (Lithuania), approximately 500 km from each other in north-south direction. The campaign started on March 1, 2021 in Siauliai (12 March in Helsinki) and continued till mid-May in Siauliai (end of May in Helsinki), thus recording the transition of the atmospheric biogenic aerosols profile from winter to summer. The observations included a variety of samplers working on different principles. The core of the program was based on 2- and 2.4–hourly sampling in Helsinki and Siauliai, respectively, with sticky slides (Hirst 24-h trap in Helsinki, Rapid-E slides in Siauliai). The slides were subsequently processed extracting the DNA from the collected aerosols, which was further sequenced using the 3-rd generation sequencing technology. The core sampling was accompanied with daily and daytime sampling using standard filter collectors. The hourly aerosol concentrations at the Helsinki monitoring site were obtained with a Poleno flow cytometer, which could recognize some of the aerosol types. The sampling campaign was supported by numerical modelling. For every sample, SILAM model was applied to calculate its footprint and to predict anthropogenic and natural aerosol concentrations, at both observation sites. The first results confirmed the feasibility of the DNA collection by the applied techniques: all but one delivered sufficient amount of DNA for the following analysis, in over 40% of the cases sufficient for direct DNA sequencing without the PCR step. A substantial variability of the DNA yield has been noticed, generally not following the diurnal variations of the total-aerosol concentrations, which themselves showed variability not related to daytime. An expected upward trend of the biological material amount towards summer was observed but the day-today variability was large. The campaign DNA analysis produced the first high-resolution dataset of bioaerosol composition in the NorthEuropean spring. It also highlighted the deficiency of generic DNA databases in applications to atmospheric biota: about 40% of samples were not identified with standard bioinformatic methods

Higher airborne pollen concentrations correlated with increased SARS-CoV-2 infection rates, as evidenced from 31 countries across the globe

Pollen exposure weakens the immunity against certain seasonal respiratory viruses by diminishing the antiviral interferon response. Here we investigate whether the same applies to the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is sensitive to antiviral interferons, if infection waves coincide with high airborne pollen concentrations. Our original hypothesis was that more airborne pollen would lead to increases in infection rates. To examine this, we performed a cross-sectional and longitudinal data analysis on SARS-CoV-2 infection, airborne pollen, and meteorological factors. Our dataset is the most comprehensive, largest possible worldwide from 130 stations, across 31 countries and five continents. To explicitly investigate the effects of social contact, we additionally considered population density of each study area, as well as lockdown effects, in all possible combinations: without any lockdown, with mixed lockdown−no lockdown regime, and under complete lockdown. We found that airborne pollen, sometimes in synergy with humidity and temperature, explained, on average, 44% of the infection rate variability. Infection rates increased after higher pollen concentrations most frequently during the four previous days. Without lockdown, an increase of pollen abundance by 100 pollen/m3 resulted in a 4% average increase of infection rates. Lockdown halved infection rates under similar pollen concentrations. As there can be no preventive measures against airborne pollen exposure, we suggest wide dissemination of pollen−virus coexposure dire effect information to encourage high-risk individuals to wear particle filter masks during high springtime pollen concentrations.</p