Aerobiologia最新文献

Ramularia leaf spot is a major economic disease of barley caused by the dothidiomycete fungus Ramularia collo-cygni. The fungus has a complex life cycle which includes extensive late season spore release events and a seed-borne phase. Predicting disease epidemics during the growing season remains a difficult challenge. To better understand the interaction between spore movement and disease epidemics, spore samplers were set up in Germany (2 sites over 4 years), Poland (7 sites over 2 years) and the UK (2 sites over 9 years), where the disease has been observed. Spore concentrations were determined using a real-time PCR assay, and meteorological data were obtained from co-located automatic stations. Spore release events were seen to peak in June on mainland Europe and July in the UK. The pattern of spore release was broadly similar across countries with earlier peaks in mainland Europe. A relationship was observed in the UK between July spore levels and disease in following winter barley crops. Rainfall and temperature were proposed as significant drivers of spore release in these months. The major environmental parameter associated with spore release across the two UK sites was crop surface wetness, although some site-specific interactions were noted for rainfall and wind movement. Regression analysis of spore patterns and disease epidemics indicates a relationship between spore levels 75 and 105 days pre-harvest and final disease levels in UK winter barley crops. This relationship was not observed in spring barley. The implications on risk forecasts are discussed.

Due to the increase in allergies, aerobiological studies carried out in cities are essential to keep the population informed about the pollen atmospheric concentrations detected. However, the high cost and complexity of aerobiological studies often mean that the information is generated from a single sampling point that may not be representative of the entire city. In this study, the data obtained by two volumetric pollen traps, located in the coastal city of Malaga (Spain) were analyzed. One of the pollen traps was situated in the city center while the other was located on the city outskirts, 5 km away from the first. This was complemented with a meteorological and land use analysis to determine their influence on the pollen concentrations. Despite being located within the same city, the data obtained from both collectors showed significant differences in the relative abundance and annual integrals of the main pollen types, as well as in the periods in which elapse their main pollen seasons. These differences were more notable in the case of Amaranthaceae, Casuarina, Parietaria and Plantago pollen types due to the asymmetric distribution of green areas, agro-forestry areas and urban surfaces within the city, as well as the influence of local wind dynamics on the airborne pollen detected. Despite that, some differences were also observed in the other pollen types. For all the above, we consider that it is important to keep operational several sampling points in cities of a certain magnitude to provide more detailed information about atmospheric pollen concentrations.

Impact of climate change affects chilling and heat accumulation that phenological development of plant needs, air temperature being determinant for flowering, pollination and fruit production, but few knowledges are available in the winter and spring climate of Tétouan. The physiological mechanisms of the reproductive cycle that controls pollen emission are related with temperature, and different environmental factors regulate strongly the reproductive phases of the plant’s life cycle. However, from an empirical point of view, the alternance between endodormancy and ecodormancy is not well detectable. Our work focuses on determining the heat accumulation periods associated with the thermal balance needed to fulfill the chilling and heat required for budbreak and bloom timing. To evaluate Morus, Pistacia, Quercus and Olea response to changes in chill and heat accumulation rates, the Dynamic Model and the Growing Degree-Days Method were used. Regression analyses identified the chilling and forcing periods for these taxa. Over the past 12 years, chill accumulation during tree dormancy increased significantly for most of woody taxa studied, while heat accumulation decreased not significantly for all taxa. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation.

Due to the large diversity and quantity of fungal spores, such aerobiological studies are not so abundant and haven’t been done in Serbia so far. As the Pannonian plain is listed as a source of fungal spores all around Europe, our study aimed to describe the aerobiological characteristics of airborne fungal spores measured in location representative for the Pannonian plain during the wheat harvest period and to evaluate automatic bioaerosol monitoring for quantification of total airborne fungal spores. The study revealed that Cladosporium, Alternaria, and Coprinus accounted for over 90% of the total fungal spores count. The relation to meteorology confirmed a distinction between “dry” and “wet” spores and their diurnal cycles, as Ganoderma and Coprinus peaked around dawn, and Alternaria and Cladosporium peaks correlated with daily peaks of temperature and relative humidity. Automatically quantified daily concentrations of total airborne fungal spores showed a statistically significant positive correlation (Pearson r = 0.55, p < 0.01) to values obtained from the manual Hirst method. The same correlations were found for total pollen (Pearson r = 0.60, p < 0.01) and starch granules (Spearman r = 0.80, p < 0.01). A low intensity of fluorescence measurements for fungal spores requires a separate automatic detection from pollen and indicates the need for a good quality training dataset. Thus, Hirst-type measurements provide an essential model for classifying bioaerosols with artificial intelligence.

Airborne pollen can trigger allergic reactions, but exposure is poorly understood because neither regional pollen models nor monitoring networks adequately capture the extensive spatial variation in pollen concentrations observed at urban scales. Here, we test whether pollen emissions from individual source plants can predict spatial variation in airborne pollen at scales of hundreds of meters to kilometers. To do so, we quantified pollen release within a city for oaks (Quercus) by mapping individual trees using remote sensing, calculating each tree’s pollen production with allometric equations, and estimating the timing of flowering with satellite-derived temperature data. We also measured airborne pollen concentrations multiple times a week at 9 sites in the first year and at 15 sites in the second year. Predicted pollen release explained 86% of the spatial variation in measured airborne pollen across the pollen season and 55% of local airborne pollen concentrations on any given day, whereas a traditional monitoring station measurements explained only 34% of spatiotemporal variation. Airborne pollen was best predicted by pollen release within approximately 1–2 km. Our results demonstrate that airborne pollen can be effectively modeled within cities by quantifying pollen release from individual trees. This type of approach could potentially be applied elsewhere, improving predictions of airborne pollen within cities and providing opportunities to avoid allergen exposure, fine-tune medication use, and better inform tree management decisions.

Graphical abstract

The Hirst-type pollen trap (1952) is the most common device for aerobiological measurements of pollen and fungal spores in ambient air. In the 1960s the in-line flowmeter was removed and studies since then showed considerable variability in the airflow pumped through the instrument when using hand-held rotameters with an internal airflow resistance to adjust flowrates. To avoid this problem, our study compared the variability of airflow rates of Hirst-type traps when using commercially-available low-resistance airflow meters (heat anemometers) at various timescales. Experiments were conducted in Munich (Germany) and Payerne (Switzerland), using 4 different easyFlux® instruments and 6 Hirst-type pollen traps. Measurements were taken on an hourly basis from dawn to dusk at both locations, and in addition at Payerne, weekly observations over a period of one year. When using the common hand-held rotameters (with airflow resistance) the flow was 28.3% lower than with resistance-free flowmeter (i.e., measured 10 L/min which was in reality 12.8 L/min). The coefficient of variation between the four easyFlux® devices ranged from 0.32% to 1.55% over one day and from 2.88% to 8.17% over an entire year. Some of the traps showed surprising flow variations during the day. Furthermore, flowrates deviated more when measurements were made at the point where the double-sided tape is behind the orifice than elsewhere on the drum. The measurements away from this point are representative of the flow rates for most of the period of operation and flow calibration should thus be carried out away from this point, contrary to the current procedure.

There is a need for information on pollen exposure to assess allergy risk. Monitoring of aeroallergens in a city is usually limited to the use of a single trap for the whole area. While a single trap provides enough information on background pollen concentration for the area, varying pollen exposure across different urban environments, however, is not considered. In this study, we analysed aerobiological data of three pollen seasons (2017–2020) recorded with a volumetric pollen trap in Sydney, Australia. In order to assess spatial differences in pollen exposure across the city, we installed ten gravimetric traps recording pollen deposition for eight weeks during the summer of 2019/2020. We considered the influence of meteorological variables, land use, urbanisation and distance to the sea. Our results showed differences in pollen season characteristics across the three analysed seasons and correlations with meteorological parameters. Considering all years, we found for Poaceae and Alternaria the strongest positive correlation with mean temperature and for Myrtaceae and Cupressaceae with maximum temperature. Likewise, there were negative correlations with humidity (Myrtaceae, Cupressaceae, Alternaria) and precipitation (Myrtaceae, Cupressaceae). Days with medically relevant pollen and spore concentrations varied between years and we recorded the highest amount in 2017/2018 for Poaceae and Alternaria and in 2019/2020 for Myrtaceae. In addition, we found spatial and temporal variations of pollen deposition. However, we did not detect significant correlations between pollen deposition and land use, which can be attributable to drought conditions prior to the sampling campaign and the temporal setting in the pollen season. This study highlights the importance of continuous volumetric aerobiological monitoring as well as the assessment of pollen exposure at several locations across a large urban area.

Ramularia leaf spot is a major economic disease of barley caused by the dothidiomycete fungus Ramularia collo-cygni. The fungus has a complex life cycle which includes extensive late season spore release events and a seed-borne phase. Predicting disease epidemics during the growing season remains a difficult challenge. To better understand the interaction between spore movement and disease epidemics, spore samplers were set up in Germany (two sites over 4 years), Poland (seven sites over 2 years) and the UK (two sites over 9 years), where the disease has been observed. Spore concentrations were determined using a real time PCR assay, and meteorological data were obtained from co-located automatic stations. Spore release events were seen to peak in June on mainland Europe and July in the UK. The pattern of spore release was broadly similar across countries with earlier peaks in mainland Europe. A relationship was observed in the UK between July spore levels and disease in following winter barley crops. Rainfall and temperature were proposed as significant drivers of spore release in these months. The major environmental parameter associated with spore release across the two UK sites was crop surface wetness, although some site-specific interactions were noted for rainfall and wind movement. Regression analysis of spore patterns and disease epidemics indicates a relationship between spore levels 75–105 days pre harvest and final disease levels in UK winter barley crops. This relationship was not observed in spring barley. The implications on risk forecasts are discussed.

We present the first implementation of the monitoring of airborne fungal spores in real-time using digital holography. To obtain observations of Alternaria spp. spores representative of their airborne stage, we collected events measured in the air during crop harvesting in a contaminated potato field, using a Swisens Poleno device. The classification algorithm used by MeteoSwiss for operational pollen monitoring was extended by training the system using this additional dataset. The quality of the retrieved concentrations is evaluated by comparison with parallel measurements made with a manual Hirst-type trap. Correlations between the two measurements are high, especially over the main dispersion period of Alternaria spp., demonstrating the potential for automatic real-time monitoring of fungal spores.