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Ice nucleation activity and aeolian dispersal success in airborne and aquatic microalgae

Tesson, Sylvie V.M. LU and Šantl-Temkiv, Tina (2018) In Frontiers in Microbiology 9(NOV).
Abstract

Microalgae are common members of the atmospheric microbial assemblages. Diverse airborne microorganisms are known to produce ice nucleation active (INA) compounds, which catalyze cloud and rain formation, and thus alter cloud properties and their own deposition patterns. While the role of INA bacteria and fungi in atmospheric processes receives considerable attention, the numerical abundance and the capacity for ice nucleation in atmospheric microalgae are understudied. We isolated 81 strains of airborne microalgae from snow samples and determined their taxonomy by sequencing their ITS markers, 18S rRNA genes or 23S rRNA genes. We studied ice nucleation activity of airborne isolates, using droplet freezing assays, and their ability to... (More)

Microalgae are common members of the atmospheric microbial assemblages. Diverse airborne microorganisms are known to produce ice nucleation active (INA) compounds, which catalyze cloud and rain formation, and thus alter cloud properties and their own deposition patterns. While the role of INA bacteria and fungi in atmospheric processes receives considerable attention, the numerical abundance and the capacity for ice nucleation in atmospheric microalgae are understudied. We isolated 81 strains of airborne microalgae from snow samples and determined their taxonomy by sequencing their ITS markers, 18S rRNA genes or 23S rRNA genes. We studied ice nucleation activity of airborne isolates, using droplet freezing assays, and their ability to withstand freezing. For comparison, we investigated 32 strains of microalgae from a culture collection, which were isolated from polar and temperate aqueous habitats. We show that ∼17% of airborne isolates, which belonged to taxa Trebouxiphyceae, Chlorophyceae and Stramenopiles, were INA. A large fraction of INA strains (over 40%) had ice nucleation activity at temperatures ≥-6°C. We found that 50% of aquatic microalgae were INA, but the majority were active at temperatures <-12°C. Most INA compounds produced by microalgae were proteinaceous and associated with the cells. While there were no deleterious effects of freezing on the viability of airborne microalgae, some of the aquatic strains were killed by freezing. In addition, the effect of desiccation was investigated for the aquatic strains and was found to constitute a limiting factor for their atmospheric dispersal. In conclusion, airborne microalgae possess adaptations to atmospheric dispersal, in contrast to microalgae isolated from aquatic habitats. We found that widespread taxa of both airborne and aquatic microalgae were INA at warm, sub-zero temperatures (>-15°C) and may thus participate in cloud and precipitation formation.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Airborne microalgae, Aquatic microalgae, Atmospheric deposition, Heterogeneous ice nucleation, Ice nucleation activity
in
Frontiers in Microbiology
volume
9
issue
NOV
publisher
Frontiers
external identifiers
  • scopus:85056881631
ISSN
1664-302X
DOI
10.3389/fmicb.2018.02681
language
English
LU publication?
yes
id
61cc3596-b05f-4e5f-8988-b1b198f20d2a
date added to LUP
2018-11-29 13:18:08
date last changed
2019-03-01 03:00:10
@article{61cc3596-b05f-4e5f-8988-b1b198f20d2a,
  abstract     = {<p>Microalgae are common members of the atmospheric microbial assemblages. Diverse airborne microorganisms are known to produce ice nucleation active (INA) compounds, which catalyze cloud and rain formation, and thus alter cloud properties and their own deposition patterns. While the role of INA bacteria and fungi in atmospheric processes receives considerable attention, the numerical abundance and the capacity for ice nucleation in atmospheric microalgae are understudied. We isolated 81 strains of airborne microalgae from snow samples and determined their taxonomy by sequencing their ITS markers, 18S rRNA genes or 23S rRNA genes. We studied ice nucleation activity of airborne isolates, using droplet freezing assays, and their ability to withstand freezing. For comparison, we investigated 32 strains of microalgae from a culture collection, which were isolated from polar and temperate aqueous habitats. We show that ∼17% of airborne isolates, which belonged to taxa Trebouxiphyceae, Chlorophyceae and Stramenopiles, were INA. A large fraction of INA strains (over 40%) had ice nucleation activity at temperatures ≥-6°C. We found that 50% of aquatic microalgae were INA, but the majority were active at temperatures &lt;-12°C. Most INA compounds produced by microalgae were proteinaceous and associated with the cells. While there were no deleterious effects of freezing on the viability of airborne microalgae, some of the aquatic strains were killed by freezing. In addition, the effect of desiccation was investigated for the aquatic strains and was found to constitute a limiting factor for their atmospheric dispersal. In conclusion, airborne microalgae possess adaptations to atmospheric dispersal, in contrast to microalgae isolated from aquatic habitats. We found that widespread taxa of both airborne and aquatic microalgae were INA at warm, sub-zero temperatures (&gt;-15°C) and may thus participate in cloud and precipitation formation.</p>},
  articleno    = {2681},
  author       = {Tesson, Sylvie V.M. and Šantl-Temkiv, Tina},
  issn         = {1664-302X},
  keyword      = {Airborne microalgae,Aquatic microalgae,Atmospheric deposition,Heterogeneous ice nucleation,Ice nucleation activity},
  language     = {eng},
  month        = {11},
  number       = {NOV},
  publisher    = {Frontiers},
  series       = {Frontiers in Microbiology},
  title        = {Ice nucleation activity and aeolian dispersal success in airborne and aquatic microalgae},
  url          = {http://dx.doi.org/10.3389/fmicb.2018.02681},
  volume       = {9},
  year         = {2018},
}