Aquatic Sciences Meeting, Albuquerque 2001
| SS02 Photochemical Reactions In Surface Waters: A Major Issue in the 21st Century? (Environmental Connections) |
| Date: Thursday, February 15, 2001, Time: 12:00:00 PM |
| Location: San Miguel |
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| Kitidis, V, , Ocean Research Group, University of Newcastle, Newcastle-upon-Tyne, United Kingdom, vassilis.kitidis@ncl.ac.uk |
| Stubbins, A, P, Ocean Research Group, University of Newcastle, Newcastle-upon-Tyne, United Kingdom, a.p.stubbins@ncl.ac.uk |
| Uher, G, , Ocean Research Group, University of Newcastle, Newcastle-upon-Tyne, United Kingdom, |
| Upstill-Goddard, R, , Ocean Research Group, University of Newcastle, Newcastle-upon-Tyne, United Kingdom, |
| Woodward, E, M, Plymouth Marine Laboratory, , United Kingdom, |
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| PHOTOPRODUCTION OF AMMONIA AND NITRITE FROM CDOM IN THE MARINE ENVIRONMENT |
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| In marine waters, the photochemical production of dissolved inorganic nitrogen (DIN), i.e. ammonia and nitrite, from terrestrially derived coloured dissolved organic matter (CDOM) may be an important, additional source of bioavailable nitrogen. This photochemical DIN release may have profound implications for the nutrient balance of coastal and shelf seas during periods of low external supply (e.g. summer stratification), when the mixed layer is depleted of inorganic nitrogen. Here, we present results from studies of DIN photoproduction and CDOM distribution in estuarine and marine waters. Water samples were collected from the Tyne and Tamar estuaries, adjacent coastal waters, and the open ocean and were analysed for inorganic nutrients and CDOM spectral characteristics. DIN photoproduction rates were determined in irradiation experiments using sunlight and a solar simulator. Photoproduction rates of ammonia and nitrite in natural waters were in the order of 100 nM/h and 10 nM/h, respectively, and varied with the nature and occurrence of CDOM. We discuss the relation between DIN photoproduction and CDOM distribution and spectral characteristics, and attempt a preliminary assessment of the role of DIN photoproduction in estuarine and marine waters. |
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