Photochemical Mineralization of Terrigenous DOC to Dissolved Inorganic Carbon in Ocean

When terrigenous dissolved organic carbon (tDOC) rich in chromophoric dissolved organic matter (tCDOM) enters the ocean, solar radiation mineralizes it partially into dissolved inorganic carbon (DIC). This study addresses the amount and the rates of DIC photoproduction from tDOC and the area of ocean required to photomineralize tDOC. We collected water samples from 10 major rivers, mixed them with artificial seawater, and irradiated them with simulated solar radiation to measure DIC photoproduction and the photobleaching of tCDOM. The linear relationship between DIC photoproduction and tCDOM photobleaching was used to estimate the amount of photoproduced DIC from the tCDOM fluxes of the study rivers. Solar radiation was estimated to mineralize 12.5 +/- 3.7 Tg C yr(-1) (10 rivers)(-1) or 18 +/- 8% of tDOC flux. The irradiation experiments also approximated typical apparent spectral quantum yields for DIC photoproduction (phi(lambda)) over the entire lifetime of the tCDOM. Based on phi(lambda)s and the local solar irradiances in river plumes, the annual areal DIC photoproduction rates from tDOC were calculated to range from 52 +/- 4 (Lena River) to 157 +/- 2 mmol C m(-2) yr(-1) (Mississippi River). When the amount of photoproduced DIC was divided by the areal rate, 9.6 +/- 2.5 x 10(6) km(2) of ocean was required for the photomineralization of tDOC from the study rivers. Extrapolation to the global tDOC flux yields 45 (31-58) Tg of photoproduced DIC per year in the river plumes that cover 34 (25-43) x 10(6) km(2) of the ocean.Peer reviewe

Energiatehokkaan mobiilisovellusohjelmoinnin välineitä

Älypuhelimista on tullut suosittuja ja ne ovat kehittyneet nopeasti, tarjoten jatkuvasti tehokkaampia suorittimia sekä nopeampia langattomia verkkotekniikoita. Laitteiston kehittyminen on luonut markkinat entistä monipuolisemmille ja kehittyneemmille mobiilisovelluksille, mutta mobiililaitteiden käytettävyys riippuu kokonaan niiden akun mahdollistamasta käyttöajasta. Niinpä sovelluskehittäjien on pystyttävä tarjoaman energiatehokkaita sovelluksia, joissa on silti monimutkaisia toimintoja. Energiatehokkaiden sovellusten kehittäminen vaatii kuitenkin energiatehokkaan ohjelmoinnin käytänteitä ja menetelmiä valittujen ratkaisujen energiankulutuksen arviointiin. Tässä työssä suoritetaan kattava kirjallisuuskatsaus energiankulutuksen arviointimenetelmistä ja energiatehokkaan mobiiliohjelmoinnin käytänteistä. Tunnistettuja energiankulutuksen arviointimenetelmiä myös vertaillaan ja käydään läpi niihin liittyviä mobiililaitealustan ja ohjelmistopinon aiheuttamia haasteita ja rajoituksia. Työn empiirisessä osassa joitain tunnistetuista ohjelmointikäytänteistä sovelletaan reittimuotoisten paikkatietojen keräämiseen ja lähettämiseen kehitettävään komponenttiin. Lisäksi tässä yhteydessä kehitetään edullinen energiankulutuksen mittalaite, jota käytetään komponentille tehtävissä testeissä.Smartphones have gained an extensive user base and are constantly evolving to provide more powerful processor and better connectivity. These improvements have created an increasing demand for more advanced mobile software applications. At the same time, user experience of mobile devices relies on their battery lifetime. As a result, application developers need to be able to provide advanced functionality while keeping the software highly energy efficient. However, developing such applications requires both guidelines for energy efficient programming and methods for assessing the energy consumption of the application code. In this work, a comprehensive literature review of energy assessment methodologies and actionable practices for mobile application programming will be provided. The properties of the covered assessment methods will also be compared and the limitations imposed by the mobile device hardware and software stack on the methods will be discussed. In the empirical part some of the introduced programming practices are evaluated in the context of a background component for collecting and uploading location trails. In addition, an affordable energy measurement instrument will be designed and built for assessment of the energy consumption of the component

DNA recovery from Droplet Digital™ PCR emulsions using liquid nitrogen

Droplet microfluidics is a technology that enables the production and manipulation of small volumes. In biosciences, the most popular application of this technology is Droplet Digital™ PCR (ddPCR™), where parallel nanoliter-scale PCR assays are used to provide a high sensitivity and specificity for DNA detection. However, the recovery of PCR products for downstream applications such as sequencing can be challenging due to the droplets' stability. Here we compared five methods for disrupting the droplets to recover DNA. We found that rapid freezing in liquid nitrogen results in a clear phase separation and recovery of up to 70% of the DNA content. Liquid nitrogen freezing can thus offer a simple and environmentally friendly protocol for recovering DNA from ddPCR.peerReviewe

Original data for article: Comparison of epifluorescence microscopy and flow cytometry in counting freshwater picophytoplankton

The dataset is divided into four subfolders: 1) "SEM experiment data" contains Scanning Electron Microscopy data, epifluorescence microscopy data and flow cytometry data of cultured Synechococcus, Chroococcus and Snowella 2) "raw data" contains epifluorescence microscopy and flow cytometry data of picophytoplankton from Finnish lakes. This has two sub folders "flow cytometry raw" and "microscopy raw" 3) "flow cytometry calibration data" contains data for cell size calibration with latex beads and volumetric calibration for the flow cytometer 4) "processed flow and microscopy data" contains excel workbooks for the figures shown in the manuscip

Comparing the Ecotoxicological Effects of Perfluorooctanoic Acid (PFOA) and Perfluorohexanoic Acid (PFHxA) on Freshwater Microbial Community

The ubiquitous presence of perfluorinated carboxylic acids (PFCAs) around the globe has attracted increasing attention, due to their persistency, bioaccumulation, and toxicity. Nevertheless, the ecotoxicological effects of the compounds on aquatic microorganisms has remained understudied. Hence, the present study focused on determining, and comparing, the effects of regulated long-chain PFCA, perfluorooctanoic acid (PFOA), and nonregulated short-chain PFCA, perfluorohexanoic acid (PFHxA), on the diversity, structure, microbial growth, and activity of a freshwater microbial community. In the experiment, lake water was incubated for a period of four weeks at three different concentrations of the studied PFCAs: 100 ng/L, 100 μg/L, and 10 mg/L. The results suggested that both compounds at high concentration (10 mg/L) altered the structure of the microbial community, but the diversity was not affected. Both compounds also decreased the microbial biovolume at higher concentrations and the increasing dose added to the significance of the impact, whereas inhibition of net microbial respiration could not be demonstrated. PFOA showed more potent toxicity towards the microbial community as it caused more significant structural changes to the community and significantly inhibited microbial growth even at the low 100 ng/L concentration. This study helps to better understand the ecotoxicity of PFCAs and to assess the environmental risks associated with their use. Additionally, these results can help policy makers to better assess the environmental risks posed by short-chain PFCAs on aquatic ecosystems.peerReviewe