The relevance of nanoscale biological fragments for ice nucleation in clouds

Most studies of the role of biological entities as atmospheric ice-nucleating particles have focused on relatively rare supermicron particles such as bacterial cells, fungal spores and pollen grains. However, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds. Here we show that the ice-nucleating activity of a fungus from the ubiquitous genus Fusarium is related to the presence of nanometre-scale particles which are far more numerous, and therefore potentially far more important for cloud glaciation than whole intact spores or hyphae. In addition, we quantify the ice-nucleating activity of nano-ice nucleating particles (nano-INPs) washed off pollen and also show that nano-INPs are present in a soil sample. Based on these results, we suggest that there is a reservoir of biological nano-INPs present in the environment which may, for example, become aerosolised in association with fertile soil dust particles

The study of atmospheric ice-nucleating particles via microfluidically generated droplets

Ice-nucleating particles (INPs) play a significant role in the climate and hydrological cycle by triggering ice formation in supercooled clouds, thereby causing precipitation and affecting cloud lifetimes and their radiative properties. However, despite their importance, INP often comprise only 1 in 10³–10⁶ ambient particles, making it difficult to ascertain and predict their type, source, and concentration. The typical techniques for quantifying INP concentrations tend to be highly labour-intensive, suffer from poor time resolution, or are limited in sensitivity to low concentrations. Here, we present the application of microfluidic devices to the study of atmospheric INPs via the simple and rapid production of monodisperse droplets and their subsequent freezing on a cold stage. This device offers the potential for the testing of INP concentrations in aqueous samples with high sensitivity and high counting statistics. Various INPs were tested for validation of the platform, including mineral dust and biological species, with results compared to literature values. We also describe a methodology for sampling atmospheric aerosol in a manner that minimises sampling biases and which is compatible with the microfluidic device. We present results for INP concentrations in air sampled during two field campaigns: (1) from a rural location in the UK and (2) during the UK’s annual Bonfire Night festival. These initial results will provide a route for deployment of the microfluidic platform for the study and quantification of INPs in upcoming field campaigns around the globe, while providing a benchmark for future lab-on-a-chip-based INP studies

Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters

“Super-blooms” of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine “harmful algal bloom” in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface

Effects of Trophic Skewing of Species Richness on Ecosystem Functioning in a Diverse Marine Community

Widespread overharvesting of top consumers of the world’s ecosystems has “skewed” food webs, in terms of biomass and species richness, towards a generally greater domination at lower trophic levels. This skewing is exacerbated in locations where exotic species are predominantly low-trophic level consumers such as benthic macrophytes, detritivores, and filter feeders. However, in some systems where numerous exotic predators have been added, sometimes purposefully as in many freshwater systems, food webs are skewed in the opposite direction toward consumer dominance. Little is known about how such modifications to food web topology, e.g., changes in the ratio of predator to prey species richness, affect ecosystem functioning. We experimentally measured the effects of trophic skew on production in an estuarine food web by manipulating ratios of species richness across three trophic levels in experimental mesocosms. After 24 days, increasing macroalgal richness promoted both plant biomass and grazer abundance, although the positive effect on plant biomass disappeared in the presence of grazers. The strongest trophic cascade on the experimentally stocked macroalgae emerged in communities with a greater ratio of prey to predator richness (bottom-rich food webs), while stronger cascades on the accumulation of naturally colonizing algae (primarily microalgae with some early successional macroalgae that recruited and grew in the mesocosms) generally emerged in communities with greater predator to prey richness (the more top-rich food webs). These results suggest that trophic skewing of species richness and overall changes in food web topology can influence marine community structure and food web dynamics in complex ways, emphasizing the need for multitrophic approaches to understand the consequences of marine extinctions and invasions

Aerosols in the Pre-industrial Atmosphere

Purpose of Review: We assess the current understanding of the state and behaviour of aerosols under pre-industrial conditions and the importance for climate. Recent Findings: Studies show that the magnitude of anthropogenic aerosol radiative forcing over the industrial period calculated by climate models is strongly affected by the abundance and properties of aerosols in the pre-industrial atmosphere. The low concentration of aerosol particles under relatively pristine conditions means that global mean cloud albedo may have been twice as sensitive to changes in natural aerosol emissions under pre-industrial conditions compared to present-day conditions. Consequently, the discovery of new aerosol formation processes and revisions to aerosol emissions have large effects on simulated historical aerosol radiative forcing. Summary: We review what is known about the microphysical, chemical, and radiative properties of aerosols in the pre-industrial atmosphere and the processes that control them. Aerosol properties were controlled by a combination of natural emissions, modification of the natural emissions by human activities such as land-use change, and anthropogenic emissions from biofuel combustion and early industrial processes. Although aerosol concentrations were lower in the pre-industrial atmosphere than today, model simulations show that relatively high aerosol concentrations could have been maintained over continental regions due to biogenically controlled new particle formation and wildfires. Despite the importance of pre-industrial aerosols for historical climate change, the relevant processes and emissions are given relatively little consideration in climate models, and there have been very few attempts to evaluate them. Consequently, we have very low confidence in the ability of models to simulate the aerosol conditions that form the baseline for historical climate simulations. Nevertheless, it is clear that the 1850s should be regarded as an early industrial reference period, and the aerosol forcing calculated from this period is smaller than the forcing since 1750. Improvements in historical reconstructions of natural and early anthropogenic emissions, exploitation of new Earth system models, and a deeper understanding and evaluation of the controlling processes are key aspects to reducing uncertainties in future

Neuvolatyöntekijöiden valmiudet ja toiminta infektiopositiivisen äidin hoidossa ja hoitokäytäntöjen toteutuminen

Raskaudenaikaisia infektioseulontoja on toteutettu Suomessa rutiininomaisesti 1950-luvulta lähti-en, ja nykyään ohjelma sisältää HIV-, kuppa- ja hepatiitti B –infektioiden seulonnan. Näiden infek-tioiden aiheuttama lapsen terveyttä uhkaava tauti voidaan tehokkaasti torjua ohjeiden mukaisella hoidolla. Raskaudenaikainen infektioseulonta on periaatteessa tehokas ja hyvin hoidossa koko maassa, mutta seulonnan vaikuttavuudesta ja hoitokäytännöistä yleensä tai hoitokäytäntöjen yh-teneväisyydestä ei kuitenkaan ole valtakunnallista tietoa. Tämän tutkimuksen tarkoituksena oli selvittää raskaudenaikana todettujen infektioiden olemassa olevien ohjeiden mukaisten hoitokäytäntöjen toteutumista ja arvioida positiivisen infektiolöydök-sen aiheuttamaa lisätyötä neuvolassa. Tutkimuksen tavoite on tuottaa tietoa, joka on hyödynnet-tävissä päivittäessä ja yhtenäistäessä valtakunnallisia ohjeistuksia ja suosituksia. Tutkimus oli määrällinen- eli kvantitatiivinen rekisteritutkimus, jossa olivat mukana kaikki vuosina 2005–2009 Terveyden ja hyvinvoinninlaitoksen (THL) infektioseulonnoissa positiivisen tuloksen saaneet äidit, sekä näistä raskauksista syntyneet lapset. Tutkimuksen rekisteriaineisto käsittää potilasasiakirjoista kerättyjä tietoja täydennettynä THL:n Neuvolaserologian laboratorion FMC (Finnish Maternity Cohort) seerumipankin tietoja, syntyneiden lasten- (BR Birth Register) ja hoi-toilmoitusrekisterin (Hilmo-rekisteri) tietoja. Lisäksi tutkimusaineistoon sisältyy Webropol-kyselytutkimuksen vastaukset. Kaikista tutkimukseen kuuluvista henkilöistä, joilla infektioseulon-tavaiheessa oli virallinen henkilötunnus, on kattavat FMC-, BR- ja Hilmo-rekistereistä kootut ter-veystiedot. Potilasasiakirja- ja rekisteritiedot saatiin 497 (65 %) äidistä ja lapsesta ja ne jäivät puuttumaan 120 (16 %) äidiltä ja lapselta. Webropol-kyselytutkimuksen vastauksia saatiin 137/200 äitiysneuvolatyöntekijältä eli vastausprosentti oli suhteellisen hyvä, 68.5 %. Tutkimustuloksien perusteella raskaudenaikaisten infektioiden hoidosta ei ole selkeitä valtakun-nallisia ohjeita. Neuvolan työntekijät etsivät eri lähteitä käyttäen hoito-ohjeita. Tutkimuksista selvi-si, että hepatiitti B -positiivisten naisten lapset saivat sairaalassa suositusten mukaisen immuno-globuliinin sekä ensimmäisen hepatiitti B -rokotteen. Tehosterokotteiden saannissa oli aineiston perusteella puutteellisuuksia. HIV-positiivisten naisten seuranta toteutuu pääasiassa erikoissai-raanhoidossa. Näiden naisten lapsista kaikki saivat ennaltaehkäisevän HIV- lääkityksen synty-män jälkeen. Tietoja yhdistämällä todetaan että kuppa-infektion hoito jää toteutumatta jopa noin puolella tapauksia, jotka voimassa olevien Käypä Hoito-suositusten mukaan tulisi hoitaa.The infection screening program for pregnant women in Finland includes tests for HIV, syphilis and hepatitis B. The diseases these infections cause for the baby can effectively be treated fol-lowing the instructions available. Although the screening program is well executed, there are no national statistics on the effectiveness of the screenings, the treatment practices used or the con-sistency of the treatment practices. The aim of this study is to find out how the treatment of infections found during pregnancy is car-ried out and to evaluate the amount of extra work the infection findings cause for the maternity clinic personnel. The study aims at producing information that can be utilized when updating and unifying the national instructions and recommendations. The study was carried out as a quantitative registry study, including all mothers who had been tested positive for infections in the screenings done in 2005-2009 by the National Institute of Health and Welfare (THL), as well as their children born from these pregnancies. The data com-prised of patient file data supplemented with the THL FMC (Finnish Maternity Cohort) serum bank data, the BR (Birth Register) data and information collected from the care register Hilmo. In addi-tion, the data included the replies to the Webropol questionnaire-based study. The patient case file and registry information was received on 497 mothers and children (65%) and they were missing on 120 mothers and children (16%). 137/200 Webropol responses were received from the maternity clinic personnel (response rate 68,5%). Findings revealed that there are no national instructions for the treatment of infections detected during pregnancy. The maternity clinic personnel searched treatment instructions from various sources. Findings also showed that the children of HBV positive women received immunoglobulin and their first HBV vaccination in the hospital, as recommended. Based on the data, there were inadequacies in getting the booster shots. The follow-up of HIV positive women is mainly carried out in specialized medical care facilities. All children of HIV positive women got preventive HIV medication after birth. Combination of various data revealed that as many as half of the syphilis infections requiring treatment according to the current nationanational recommendations are left without treatment

The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds.

The amount of ice present in mixed-phase clouds, which contain both supercooled liquid water droplets and ice particles, affects cloud extent, lifetime, particle size and radiative properties. The freezing of cloud droplets can be catalysed by the presence of aerosol particles known as ice nuclei. One of the most important ice nuclei is thought to be mineral dust aerosol from arid regions. It is generally assumed that clay minerals, which contribute approximately two-thirds of the dust mass, dominate ice nucleation by mineral dust, and many experimental studies have therefore focused on these materials. Here we use an established droplet-freezing technique to show that feldspar minerals dominate ice nucleation by mineral dusts under mixed-phase cloud conditions, despite feldspar being a minor component of dust emitted from arid regions. We also find that clay minerals are relatively unimportant ice nuclei. Our results from a global aerosol model study suggest that feldspar ice nuclei are globally distributed and that feldspar particles may account for a large proportion of the ice nuclei in Earth's atmosphere that contribute to freezing at temperatures below about -15 °C