Acid-Base Chemistry of Dissolved Organic Matter in Aqueous Leaf Extracts: Application to Organic Acids in Throughfall

Abstract. An organic aerosol particle has a lifetime of approximately 1 week in the atmosphere during which it will be exposed to sunlight. However, the effect of photochemistry on the propensity of organic matter to participate in the initial cloud-forming steps is difficult to predict. In this study, we quantify on a molecular scale the effect of photochemical exposure of naturally occurring dissolved organic matter (DOM) and of a fulvic acid standard on its cloud condensation nuclei (CCN) and ice nucleation (IN) activity. We find that photochemical processing, equivalent to 4.6 d in the atmosphere, of DOM increases its ability to form cloud droplets by up to a factor of 2.5 but decreases its ability to form ice crystals at a loss rate of −0.04 ∘CT50 h−1 of sunlight at ground level. In other words, the ice nucleation activity of photooxidized DOM can require up to 4 ∘C colder temperatures for 50 % of the droplets to activate as ice crystals under immersion freezing conditions. This temperature change could impact the ratio of ice to water droplets within a mixed-phase cloud by delaying the onset of glaciation and by increasing the supercooled liquid fraction of the cloud, thereby modifying the radiative properties and the lifetime of the cloud. Concurrently, a photomineralization mechanism was quantified by monitoring the loss of organic carbon and the simultaneous production of organic acids, such as formic, acetic, oxalic and pyruvic acids, CO and CO2. This mechanism explains and predicts the observed increase in CCN and decrease in IN efficiencies. Indeed, we show that photochemical processing can be a dominant atmospheric ageing process, impacting CCN and IN efficiencies and concentrations. Photomineralization can thus alter the aerosol–cloud radiative effects of organic matter by modifying the supercooled-liquid-water-to-ice-crystal ratio in mixed-phase clouds with implications for cloud lifetime, precipitation patterns and the hydrological cycle.Highlights. During atmospheric transport, dissolved organic matter (DOM) within aqueous aerosols undergoes photochemistry. We find that photochemical processing of DOM increases its ability to form cloud droplets but decreases its ability to form ice crystals over a simulated 4.6 d in the atmosphere. A photomineralization mechanism involving the loss of organic carbon and the production of organic acids, CO and CO2 explains the observed changes and affects the liquid-water-to-ice ratio in clouds.

Download Full-text

Impact of low molecular weight organic acids and dissolved organic matter on sorption and mobility of isoproturon in two soils

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2011.04.003 ◽

2011 ◽

Vol 190 (1-3) ◽

pp. 823-832 ◽

Cited By ~ 47

Author(s):

Qing Ding ◽

Hai Lang Wu ◽

Yun Xu ◽

Li Juan Guo ◽

Kai Liu ◽

...

Keyword(s):

Molecular Weight ◽

Organic Matter ◽

Dissolved Organic Matter ◽

Organic Acids ◽

Low Molecular Weight

Download Full-text

Acid-base analysis of dissolved organic matter in surface waters

Water Air & Soil Pollution ◽

10.1007/bf00192856 ◽

1989 ◽

Vol 46 (1-4) ◽

pp. 199-204

Author(s):

James R. Kramer ◽

Pierre Brassard ◽

Pamela V. Collins

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Surface Waters ◽

Acid Base ◽

Base Analysis

Download Full-text

Acid–base properties of dissolved organic matter from pristine and oil-impacted marshes of Barataria Bay, Louisiana

Marine Chemistry ◽

10.1016/j.marchem.2013.05.010 ◽

2013 ◽

Vol 155 ◽

pp. 42-49 ◽

Cited By ~ 13

Author(s):

Yaoling Zhang ◽

Nelson W. Green ◽

E. Michael Perdue

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Acid Base ◽

Barataria Bay ◽

Base Properties

Download Full-text

Acid-base properties of Baltic Sea dissolved organic matter

Journal of Marine Systems ◽

10.1016/j.jmarsys.2017.04.007 ◽

2017 ◽

Vol 173 ◽

pp. 114-121 ◽

Cited By ~ 10

Author(s):

Karoline Hammer ◽

Bernd Schneider ◽

Karol Kuliński ◽

Detlef E. Schulz-Bull

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Baltic Sea ◽

Acid Base ◽

Base Properties

Download Full-text

Acid-base properties of dissolved organic matter extracted from the marine environment

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.138437 ◽

2020 ◽

Vol 729 ◽

pp. 138437 ◽

Cited By ~ 1

Author(s):

Pablo Lodeiro ◽

Carlos Rey-Castro ◽

Calin David ◽

Eric P. Achterberg ◽

Jaume Puy ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Marine Environment ◽

Acid Base ◽

Base Properties

Download Full-text

Effect of natural organic acids on mobilization of macro- and microelements from rocks

Доклады Академии наук ◽

10.31857/s0869-56524853351-355 ◽

2019 ◽

Vol 485 (3) ◽

pp. 351-355

Author(s):

A. V. Savenko ◽

V. S. Savenko

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Organic Acids ◽

Surface Waters ◽

Sharp Increase ◽

Dissociation Constants ◽

Chemical Properties ◽

Secondary Importance ◽

Initial Stage ◽

Silicate Rocks

Experimental study of leaching of the main cations (Na, K, Mg, and Ca), alkaline and alkaliearth microelements (Li, Rb, Cs, Be, Sr, and Ba), heavy metals (Mn, Fe, Co, Ni, Cu, Zn, Cd, Tl, and Pb), hydrolyzate elements (Y, RZ, Ti, Th, and U), and anionic elements (F, Si, P, and V) from rocks of different acidity with distilled water and a multicomponent solution of organic acids, having the distribution of dissociation constants corresponding to natural dissolved organic matter was carried out. It has been shown that carboxylic acids, which are part of the dissolved organic matter contained in surface waters, cause a sharp increase in the mobilization of both the main cations and trace elements from silicate rocks. The chemical properties of the elements are of secondary importance, as was shown by the general correlation between the parameter related to the mobility of the elements at the initial stage of the leaching and their content in the rocks.

Download Full-text