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A simple model describes development of early peaks in oomycete zoospore inoculum detected in southern UK outdoors horticultural reservoirs

100%

Pettitt T. R., Skjoth C. A.

Acta Agrobotanica

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2016

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tom 69

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nr 2

The numbers of water-borne oomycete propagules in outdoor reservoirs used in horticultural nurseries within the UK are investigated in this study. Water samples were recovered from 11 different horticultural nurseries in the southern UK during Jan-May in 2 "cool" years (2010 and 2013; winter temperatures 2.0 and 0.4°C below UK Met Office 30 year winter average, respectively) and 2 "warm" years (2008 and 2012; winter temperatures 1.2 and 0.9°C above UK Met Office 30 year winter average, respectively). Samples were analyzed for total number of oomycete colony forming units (CFU), predominantly members of the families Saprolegnia-ceae and Pythiaceae, and these were combined to give monthly mean counts. The numbers of CFU were investigated with respect to prevailing climate in the region: mean monthly air temperatures calculated by using daily observations from the nearest climatological station. The investigations show that the number of CFU during spring can be explained by a linear first-order equation and a statistically significant r2 value of 0.66 with the simple relationship: [CFU] = a(T - Tb) - b, where a is the rate of inoculum development with temperature T, and b is the baseload population at temperatures below Tb. Despite the majority of oomycete CFU detected being non-phytopathogenic members of the Saprolegniaceae, total oomycete CFU counts are still of considerable value as indicators of irrigation water treatment efficacy and cleanliness of storage tanks. The presence/absence of Pythium spp. was also determined for all samples tested, and Pythium CFU were found to be present in the majority, the exceptions all being particularly cold months (January and February 2010, and January 2008). A simple scenario study (+2 deg C) suggests that abundance of water-borne oomycetes during spring could be affected by increased temperatures due to climate change.

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Ammonia concentrations over Europe – application of the WRF-Chem model supported with dynamic emission

71%

Werner M., Kryza M., Geels C., Ellermann T., Skjoth C. A.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 3

Our study focuses on the application of a static and dynamic ammonia emissions based on a Europe-wide default setting into the weather research and forecasting chemistry model (WRF-Chem), and the influence on the simulated ammonia concentrations and overall model performance. The WRF-Chem model was run twice for all of Europe at a spatial resolution of 36 x 36 km for the year 2012. In the first simulation we used a static emissions approach (the “BASE” simulation) and in the second simulation we used dynamic ammonia emissions (the “DYNAMIC” simulation). Both simulations underestimate measured concentrations of NH₃ for all seasons, have similar NMGE (about 0.7 μg m⁻³), and model hourly ammonia peaks that shift toward the afternoon hours if compared with measurements. However, for all temporal resolutions, normalised mean gross error in winter and summer is lower for DYNAMIC than for BASE. The DYNAMIC simulation also generally gives worse performance in spring for each temporal resolution. For further improvement of the modelled ammonia concentrations with WRF-Chem we suggest using a nested approach with higher spatial resolution, which will lead to better separation of the ammonia source regions from surrounding areas and take into account national practices and regulations in the emissions model, eventually only in the nested model domain.

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Risk of exposure to airborne Ambrosia pollen from local and distant sources in Europe - an example from Denmark

61%

Sommer J., Smith M., Sikoparija B., Kasprzyk I., Myszkowska D., Grewling L., Skjoth C. A.

Annals of Agricultural and Environmental Medicine

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2015

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tom 22

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nr 4

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Footprint areas of pollen from alder (Alnus) and birch (Betula) in the UK (Worcester) and Poland (Wroclaw) during 2005–2014

61%

Skjoth C. A., Bilinska D., Werner M., Malkiewicz M., Adams-Groom B., Kryza M., Drzeniecka-Osiadacz A.

Acta Agrobotanica

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2015

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tom 68

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nr 4

In this study we analyzed daily pollen concentrations of Alnus spp. and Betula spp. from Worcester, UK and Wrocław, Poland. We analyzed seasonality, annual pollen index and footprint areas for the observed pollen concentrations by using the trajectory model hybrid single particle Lagrangian integrated trajectory (HYSPLIT). We examined 10 years of data during the period 2005–2014 and found substantial differences in the seasonality, pollen indices and footprint areas. For both genera, concentrations in Wrocław are in general much higher, the seasons are shorter and therefore more intense than in Worcester. The reasons appear to be related to the differences in overall climate between the two sites and more abundant sources in Poland than in England. The footprint areas suggest that the source of the pollen grains are mainly local trees but appear to be augmented by remote sources, in particular for Betula spp. but only to a small degree for Alnus spp. For Betula spp., both sites appear to get contributions from areas in Germany, the Netherlands and Belgium, while known Betula spp. rich regions in Russia, Belarus and Scandinavia had a very limited impact on the pollen concentrations in Worcester and Wrocław. Substantial and systematic variations in pollen indices are seen for Betula spp. in Wrocław with high values every second year while a similar pattern is not observed for Worcester. This pattern was not reproduced for Alnus spp.

Ograniczanie wyników

2 Acta Agrobotanica

1 Annals of Agricultural and Environmental Medicine

1 Polish Journal of Environmental Studies

4 Skjoth C. A.

2 Kryza M.

2 Werner M.

1 Adams-Groom B.

1 Bilinska D.

1 Drzeniecka-Osiadacz A.

1 Ellermann T.

1 Geels C.

1 Grewling L.

1 Kasprzyk I.

1 Malkiewicz M.

1 Myszkowska D.

1 Pettitt T. R.

1 Sikoparija B.

1 Smith M.

1 Sommer J.

1 2017

1 2016

2 2015

A simple model describes development of early peaks in oomycete zoospore inoculum detected in southern UK outdoors horticultural reservoirs

Ammonia concentrations over Europe – application of the WRF-Chem model supported with dynamic emission

Risk of exposure to airborne Ambrosia pollen from local and distant sources in Europe - an example from Denmark

Footprint areas of pollen from alder (Alnus) and birch (Betula) in the UK (Worcester) and Poland (Wroclaw) during 2005–2014