Nav: Home

Exploring ocean waters to characterize atmospheric aerosols

March 31, 2017

Aerosols are collections of fine particles, either biological or of other types, in suspension in a gaseous medium. They play a major role in cloud formation and therefore have a strong impact on climate models. They are however extremely hard to study due to the small size and immense variety of their constituent particles. But researchers from the University of Geneva (UNIGE), Switzerland, members of the PlanetSolar Deepwater expedition, have now succeeded in linking the composition of marine biological aerosols -- and therefore their influence on the climate -- to that of bodies of water under them within the Atlantic Ocean, thereby paving the way to an indirect study of these aerosols through water analysis. This study, which has been published in Scientific Reports, will contribute to making climate models more accurate.

Aerosols are fine particles in suspension in the air. Over the oceans, some contain organic or biological ingredients (bacteria, degradation products of microscopic algae) which come from sea spray, others are transported in the air (mineral dust, smoke). They serve as seeds for forming clouds and also reflect light. Their role is extremely important for modelling clouds, and therefore for the climate in general. But due to the small size of the particles and their large quantity, it's difficult to accurately study them. So researchers at the University of Geneva (UNIGE) asked themselves if it would be possible to characterize biological aerosols through the composition of the water whence they come.

"To answer this question, we needed two tools," explains Jérôme Kasparian, Professor in the Department of Applied Physics at the UNIGE Science Faculty. "The first is a detector of fluorescence which we designed, called Biobox, and which enables us to analyse aerosol particles one by one. The spectrum gives us information on their composition and distinguishes the organic particles, which are fluorescent, from the other particles. Then we needed PlanetSolar." Indeed this research could only be undertaken over a long time period of time without any disturbances of water and air. Only PlanetSolar, a solar boat that navigated remains at sea for three months and produces no emissions, could make it possible.

During the expedition, scientists carried out analysis of the salinity, temperature, dissolved oxygen and the microalgae contained in the various bodies of water in the Atlantic, and then compared this data with that obtained by the Biobox. "And we found that they matched!" exclaims Jérôme Kasparian. The physicists discovered that biological aerosols are related to the temperature and salinity of the sea. According to previous criteria, water creates large bodies that don't inter-mix, which allows them to be differentiated. Thus, when the characteristics of a water mass were favourable for reproduction of microalgae, researchers noticed that after a certain amount of time, the aerosols detected above this same water mass contained more biological particles. The biological fraction of aerosols is therefore linked to the history of biological activity of bodies of water close to the surface. "Provided that this is also valid in oceans and seas other than the Atlantic, our research location, our results would allow us to estimate biological aerosols by directly studying the bodies of water, which would simplify aerosol caracterization and make climate models more accurate," adds Kasparian. Difficult to study directly, aerosols are now being studied via the sea, which, unlike aerosols, can easily be analysed by satellites.
-end-


Université de Genève

Related Climate Models Articles:

Scientists argue current climate change models understate the problem
A new study on the relationship between people and the planet shows that climate change is only one of many inter-related threats to the Earth's capacity to support human life.
Climate models may underestimate future warming on tropical mountains
By reconstructing past temperature change on Mount Kenya in East Africa, a new study suggests that future temperature changes on tropical mountains might be underestimated.
New research on shallow warm clouds will advance climate models, weather forecasts
David Mechem is leading a new $525,000, three-year grant from the US Department of Energy to better understand the fundamental processes governing the behavior of shallow clouds.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Impact of sea smell overestimated by present climate models
The formation of sulfur dioxide from the oxidation of dimethyl sulfide and, thus, of cooling clouds over the oceans seems to be overvalued in current climate models.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
Global climate models do not easily downscale for regional predictions
One size does not always fit all, especially when it comes to global climate models, according to Penn State climate researchers.
Technique could help climate models sweat the small stuff
Research led by a Brown University physicist reveals a way to include small-scale dynamics into computer simulations of large-scale phenomena, which could make for better climate models and astrophysical simulations.
Maryland climate and health report identifies state's vulnerabilities to climate change
A new report by the University of Maryland School of Public Health and the Maryland Department of Health and Mental Hygiene details the impacts of climate change on the health of Marylanders now and in the future.
New tool puts a consistent value on experts' uncertainty on climate change models
To bridge the gap between projections of future sea-level rise and the need to prepare for it, a Princeton University researcher and collaborators developed a method that consolidates climate models and the range of opinions that leading scientists have about them into a single, consistent set of probabilities.

Related Climate Models Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...