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The relevance of nanoscale biological fragments for ice nucleation in clouds.

O'Sullivan D, Murray BJ, Ross JF, Whale TF, Price HC, Atkinson JD, Umo NS, Webb ME - Sci Rep (2015)

Bottom Line: However, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds.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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Climate and Atmospheric Science, School of Earth &Environment, University of Leeds, UK.

ABSTRACT
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.

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Illustration of the hypothesis that nanometre-scaled INPs of biological origin may become lofted to the atmosphere in association with soil dust particles and impact cloud glaciation.Nano-INPs associated with soil dust particulates could potentially greatly outnumber intact bioaerosol particles such as pollen, fungal spores and bacteria and therefore be much more important for ice nucleation in clouds, but are not presently represented in models. The quoted particle concentrations are zonal annual means from the simulations of Hoose et al.45 for an altitude corresponding to 600 hPa.
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f1: Illustration of the hypothesis that nanometre-scaled INPs of biological origin may become lofted to the atmosphere in association with soil dust particles and impact cloud glaciation.Nano-INPs associated with soil dust particulates could potentially greatly outnumber intact bioaerosol particles such as pollen, fungal spores and bacteria and therefore be much more important for ice nucleation in clouds, but are not presently represented in models. The quoted particle concentrations are zonal annual means from the simulations of Hoose et al.45 for an altitude corresponding to 600 hPa.

Mentions: In this paper we hypothesise that biological, nanometer scaled INPs which are bound to other atmospheric particulates are important for cloud glaciation; this hypothesis is illustrated in Figure 1. As noted above, the concentration of intact bacteria, fungal spores and pollen are too low in many locations to impact cloud glaciation, but it is possible that the concentration of biological nano-INPs is much greater. Nano-scale particulates are unlikely to be emitted to the atmosphere directly, but instead can be associated with larger particles such as soil dust particles. Biological species residing in, or deposited to soil, such as fungi, bacteria and pollen, may produce nano-INPs which could attach to soil particles and subsequently become aerosolised. Indeed, recent studies examining the ice-nucleating abilities of agricultural soil dusts have shown that unidentified components of the soil organic matter can exhibit potent ice-nucleating activities17181920. Similarly, recent studies examining cloud ice crystal residues in mixed phase clouds impacted by dust aerosols transported 1000 s of miles have found that biogenic matter internally mixed with mineral dusts play an important role in ice formation within supercooled clouds2122.


The relevance of nanoscale biological fragments for ice nucleation in clouds.

O'Sullivan D, Murray BJ, Ross JF, Whale TF, Price HC, Atkinson JD, Umo NS, Webb ME - Sci Rep (2015)

Illustration of the hypothesis that nanometre-scaled INPs of biological origin may become lofted to the atmosphere in association with soil dust particles and impact cloud glaciation.Nano-INPs associated with soil dust particulates could potentially greatly outnumber intact bioaerosol particles such as pollen, fungal spores and bacteria and therefore be much more important for ice nucleation in clouds, but are not presently represented in models. The quoted particle concentrations are zonal annual means from the simulations of Hoose et al.45 for an altitude corresponding to 600 hPa.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4308702&req=5

f1: Illustration of the hypothesis that nanometre-scaled INPs of biological origin may become lofted to the atmosphere in association with soil dust particles and impact cloud glaciation.Nano-INPs associated with soil dust particulates could potentially greatly outnumber intact bioaerosol particles such as pollen, fungal spores and bacteria and therefore be much more important for ice nucleation in clouds, but are not presently represented in models. The quoted particle concentrations are zonal annual means from the simulations of Hoose et al.45 for an altitude corresponding to 600 hPa.
Mentions: In this paper we hypothesise that biological, nanometer scaled INPs which are bound to other atmospheric particulates are important for cloud glaciation; this hypothesis is illustrated in Figure 1. As noted above, the concentration of intact bacteria, fungal spores and pollen are too low in many locations to impact cloud glaciation, but it is possible that the concentration of biological nano-INPs is much greater. Nano-scale particulates are unlikely to be emitted to the atmosphere directly, but instead can be associated with larger particles such as soil dust particles. Biological species residing in, or deposited to soil, such as fungi, bacteria and pollen, may produce nano-INPs which could attach to soil particles and subsequently become aerosolised. Indeed, recent studies examining the ice-nucleating abilities of agricultural soil dusts have shown that unidentified components of the soil organic matter can exhibit potent ice-nucleating activities17181920. Similarly, recent studies examining cloud ice crystal residues in mixed phase clouds impacted by dust aerosols transported 1000 s of miles have found that biogenic matter internally mixed with mineral dusts play an important role in ice formation within supercooled clouds2122.

Bottom Line: However, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds.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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Climate and Atmospheric Science, School of Earth &Environment, University of Leeds, UK.

ABSTRACT
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.

Show MeSH