Effects of Photolysis

Photochemical processes with ecological relevance are well documented for marine and freshwater systems.

They can influence many aspects of carbon cycling in these systems and

• decrease the average molecular weight of the chromo-phoric organic substances;

• change the optical properties of the water as a result of the changes in chromophoric organic substances;

• release a complex mixture of ROS, which can hurt organisms and initiate indirect phototransformation reactions;

• produce oxidized C compounds such as CO, CO2, or short-chain fatty acids, which provide energy and carbon to heterotrophic processes;

• release P- and N-rich products: phosphate ions, amino acids, dissolved primary amines, and finally ammonia, NH4.

CM E

-

im

—. j

Figure 5 Wavelength dependence 1O2 production rates for chromophoric dissolved organic carbon compounds in a whole water column, exemplified for a midday, summer, sunlight at latitude 40° N. ■, Hietajarvi fall natural organic matter; • , Suwannee River natural organic matter; n, Suwannee River humic acid; □, Birkenes spring natural organic matter; •, Birkenes fall natural organic matter; $, Svartberget spring natural organic matter; O, peat humic acid; ■, soil fulvic acid. Reproduced from Paul A, Hackbarth S, Vogt RD, etal. (2004) Photogeneration of singlet oxygen by humic substances: Comparison of humic substances of aquatic and terrestrial origin. Photochemical and Photobiological Sciences 3: 273-280 -Reproduced by permission of The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology.

Project Earth Conservation

Project Earth Conservation

Get All The Support And Guidance You Need To Be A Success At Helping Save The Earth. This Book Is One Of The Most Valuable Resources In The World When It Comes To How To Recycle to Create a Better Future for Our Children.

Get My Free Ebook


Post a comment