Abstract
We studied the chemical and optical changes inthe dissolved organic matter (DOM) from twofreshwater lakes and a Sphagnum bog afterexposure to solar radiation. Stable carbonisotopes and solid-state 13C-NMR spectraof DOM were used together with optical andchemical data to interpret results fromexperimental exposures of DOM to sunlight andfrom seasonal observations of two lakes innortheastern Pennsylvania. Solar photochemicaloxidation of humic-rich bog DOM to smaller LMWcompounds and to DIC was inferred from lossesof UV absorbance, optical indices of molecularweight and changes in DOM chemistry. Experimentally, we observed a 1.2‰ enrichment in δ13$C and a 47% loss in aromaticC functionality in bog DOM samples exposed tosolar UVR. Similar results were observed inthe surface waters of both lakes. In latesummer hypolimnetic water in humic LakeLacawac, we observed 3 to 4.5‰enrichments in δ13C and a 30% increase inaromatic C relative to early spring valuesduring spring mixing. These changes coincidedwith increases in molecular weight and UVabsorbance. Anaerobic conditions of thehypolimnion in Lake Lacawac suggest thatmicrobial metabolism may be turning overallochthonous C introduced during springmixing, as well as autochthonous C. Thismetabolic activity produces HMW DOM during thesummer, which is photochemically labile andisotopically distinct from allochthonous DOM orautochthonous DOM. These results suggest bothphotooxidation of allochthonous DOM in theepilimnion and autotrophic production of DOM bybacteria in the hypolimnion cause seasonaltrends in the UV absorbance of lakes.
Article PDF
Similar content being viewed by others
References
Amador JA,Alexander M &Zika RG (1991) Degradation of aromatic compounds bound to humic acid by the combined action of sunlight and microorganisms. Environ. Toxicol. Chem. 10: 475
Amon RMW &Benner R (1996) Photochemical and microbial consumption of dissolved organic carbon and dissolved oxygen in the Amazon River system. Geochim. Cosmochim. Acta. 60(10): 1783-1792
Benner R,Fogel ML,Sprague KE &Hodson RE (1987) Depletion of 13C in lignin and its implications for stable carbon isotope studies. Nature 329: 708–710
Bertilsson S &Tranvik L (1998) Photochemically produced carboxylic acids as substrates for freshwater bacterioplankton. Limnol. Oceanogr. 43: 885–895
Bourbonniere RA, Miller WL & Zepp RG (1997) Distribution, flux, and photochemical production of carbon monoxide in a boreal beaver impoundment. J. Geophys. Res. 102(D24): 29, 321–329, 329
Boutton TW (1991) Stable carbon isotope ratios of natural materials: I. Sample preparation and mass spectrometric analysis. In: Coleman DC &Fry B (Eds) Carbon Isotope Techniques. Academic Press.
Brophy JE &Carlson DJ (1989) Production of refractory dissolved organic carbon by natural seawater microbial populations. Deep-Sea Res. 36: 497–507
Bunn SE &Boon PI (1993) What sources of organic carbon drive food webs in billabongs-a study based on stable isotope analysis. Oecologia. 69(1): 85–94
Calvert JG &Pitts JN (1966) Photochemistry. John Wiley & Sons, New York
Castellan A,Vanucci C &Bouas-Laurent H (1987) Photochemical degradation of lignin through ? C-O bond cleavage of non phenolic benzyl aryl ether units. A study of the photochemistry of ?(2", 4", 6"-trimethyl-phenoxy)-3, 4 dimethoxy toluene. Holzfouschung 41: 231–238
Chen YS,Khan U &Schnitzer S (1978) Ultraviolet irradiation of dilute fulvic acid solutions. Soil Sci. Am. J. 42: 292–296
Cherrier J,Bauer JE,Druffel ERM,Coffin RB &Chanton JP (1999) Radiocarbon in marine bacteria: Evidence for the age of assimilated organic matter. Limnol Oceanograph. 44(3): 730–736
Clair TA,Sydor M,Kramer JR &Eaton DR (1991) Concentration of aquatic dissolved organic matter by reverse osmosis. Water Res. 15: 1033–1037
DeHaan H (1993) Solar UV-light penetration and photodegradation of humic substances in peaty lake water. Limnol. Oceanogr. 38: 1072–1076
DeHaan H &DeBoer T (1987) Applicability of light absorbance and fluorescence as measures of concentration and molecular size of dissolved organic carbon in humic Lake Tjeukemeer. Water Resour. 21: 731–734
Ertel J (1990) Photochemistry of dissolved organic matter: An organic geochemical perspective. In: Effects of Solar Radiation on Biogeochemical Dynamics in Aquatic Environments. Woods Hole Oceanogr. Tech. Rep. WHOI-90-90
Fry B &Sherr EB (1984) ? 13Cmeasurements as indicators of carbon flow in marine and freshwater ecosystems. Contrib. Mar. Sci. 27: 13–47
Gelwicks JT,Risatti JB &Hayes JM (1994) Carbon isotope effects associated with aceticlastic methanogenesis. App. Env. Microb. 60: 467–472
Gleixner G &Schmidt HL (1998) On-line determination of group-specific isotope ratios in model compounds and aquatic humic substances by coupling pyrolysis to GC-C-IRMS. In: Stankiewicz BA &van Bergen PF (Eds) Nitrogen-containing Macromolecules in the Bio-and Geosphere (pp 34–46). ACS Symposium Series 707
Golterman HL (1971) Methods for Chemical Analysis of Fresh Waters. IBP Handbook No 8, 3rd Printing, Blackwell Scientific Publishers, Oxford.
Graneli W,Lindell M &Tranvik L (1996) Photooxidative production of dissolved inorganic carbon in lakes of different humic content. Limnol. Oceanogr. 41: 698-706
Harvey GR &Boran DA (1985) Geochemistry of humic substances in seawater. In: Aiken GR,McKnight DM,Wershaw RL &MacCarthy P (Eds) Humic Substances in Sediment, Soil, and Water: Geochemistry, Isolation, and Characterization (pp 233–249). J Wiley & Sons, New York
Hedges JI,Keil RG &Benner R (1997) What happens to terrestrial organic matter in the ocean? Org. Geochem. 27: 195–212
Herzceg AL (1988) Early diagenesis of organic matter in lake sediments: A stable carbon isotope study of pore waters. Chem. Geol. (Isot. Geosci. Sect.) 72: 199–209
Kieber DJ,McDaniel J &Mopper K (1989) Photochemical source of biological substrates in seawater: Implications for carbon cycling. Nature. 341: 637–639
Kieber RJ,Hydro LH &Seaton PJ (1997) Photooxidation of triglycerides and fatty acids in seawater: Implication toward the formation of marine humic substances. Limnol. Oceanogr. 42: 1454–1462
Kinchesh P,Powlson DS,Randall EW (1995) European J. Soil Sci. 46: 125–138
Kling GW,Kipphut GW &Miller MC (1991) Arctic lakes and streams as gas conduits to the atmosphere: Implications for tundra carbon budgets. Science. 251: 298–301
Koussai AM &Zika RG (1992) Light-induced destruction of the absorbance property of dissolved organic matter in seawater. Toxicol. Environ. Chem. 35: 195–211
Kulovaara M,Corin N,Backlund P &Tervo J (1996) Impact of UV254-radiation on aquatic humic substances. Chemosphere 33(5): 783–790
Lindell M,Graneli W &Tranvik L (1995) Enhanced bacterial growth in response to photochemical transformation of dissolved organic matter. Limnol. Oceanogr. 40: 195–199
Madronich S (1993) UV radiation in the natural and perturbed atmosphere. In: Tevini M (Ed.) UV-B Radiation and Ozone Depletion: Effects on Humans, Animals, Plants, Microorganisms, and Materials. Lewis
Miles CJ &Brezonik PL (1981) Oxygen consumption in humic-colored waters by a photochemical ferrous-ferric catalytic cycle. Environ. Sci. Technol. 15: 1089–1095
Miller WM (1994) Recent advances in the photochemistry of natural dissolved organic matter. In: Helz GR, et al. (Eds) Aquatic and Surface Photochemistry (pp 111–128). Lewis Publishers, Boca Raton
Miller WM &Zepp RG (1995) Photochemical production of dissolved inorganic carbon from terrestrial organic matter: Significance to the oceanic organic carbon cycle. Geophys. Res. Lett. 22: 417–420
Molot LA &Dillon PJ (1996) Storage of terrestrial carbon in boreal lake sediments and evasion to the atmosphere. Global Biogeochem. Cycle. 10(3): 483–492
Molot LA &Dillon PJ (1997) Photolytic regulation of dissolved organic carbon in northern lakes. Global Biogeochem. Cycles. 11(3): 357–365
Morris DP,Zagarese HE,Williamson CE,Balseiro EG,Hargreaves BR,Modenutti B,Moeller RE &Queimalinos C (1995). The attenuation of solar UV radiation in lakes and the role of dissolved organic carbon. Limnol. Oceanogr. 40: 1381–1391
Morris DP &Hargreaves BR (1997) The role of photochemical degradation of dissolved organic carbon in regulating the UV transparency of three lakes on the Pocono Plateau. Limnol. Oceanogr. 42(2): 239–349
Mopper K,Zhou X,Kieber RJ,Sikorski RG &Jones RD (1991) Photochemical degradation of dissolved organic carbon and its impact on the oceanic carbon cycle. Nature 353: 60–62
Opsahl S &Benner R (1998) Photochemical reactivity of dissolved lignin in river and ocean waters. Limnol. Oceanogr. 43(6): 1297–1304
Osburn CL,Zagarese HE,Morris DP,Hargreaves BR &Cravero W (2000) Calculation of spectral weighting functions for the solar photobleaching of chromophoric dissolved organic matter in temperate lakes. Limnol Oceanogr. In press
Salonen K &Vähätalo A (1994) Photochemical mineralization of dissolved organic matter in Lake Skjervatjern. Environ. Int. 20: 307–312
Schiff SL,Aravena R,Trumbore SE &Dillon PJ (1990) Dissolved organic carbon cycling in forested watersheds: a carbon isotope approach. Wat. Res. Research 26(12): 2949–2957
Schmidt HL &Gleixner G (1998) Carbon isotope effects on key reactions in plant metabolism and 13C-patterns in natural compounds. In: Griffiths H (Ed.) Stable Isotopes (pp 13–25)
Schulten HR &Gleixner G (1998) Analytical pyrolysis of humic substances and dissolved organic matter in aquatic systems: structure and origin. Wat. Res. 33(11): 2489–2498
Sharp JH,Benner R,Bennett L,Carlson CA,Dow R &Fitzwater SE (1993) Reevaluation of high-temperature combustion and chemical oxidation measurements of dissolved organic carbon in seawater. Limnol. Oceanogr. 38(8): 1774–1782
Stainton MP (1973) A syringe gas-stripping procedure for gas chromatographic determination of dissolved inorganic and organic carbon in fresh water and c carbonates in sediments. J. Fish. Res. Board Can. 30: 1441–1445
Steinberg C &Muenster U (1985) Geochmeistry and ecological role of humic substances in lakewater. In: Aiken GR,McKnight DM,Wershaw RL &MacCarthy P (Eds) Humic Substances in Sediment, Soil, and Water: Geochemistry, Isolation, and Characterization (pp 105–147). J Wiley & Sons, New York
Strome DJ &Miller MC (1978) Photolytic changes in dissolved humic substances. Verh. Internat. Verein. Limnol. 20: 1248–1254
Tevini M (1993) UV-B Radiation and Ozone Depletion. Lewis
Thorn KA,Folan DW &MacCarthy P (1991) Characterization of the International Humic Substances Society standard and reference fulvic and humic acids by solution state carbon-13 and hydrogen-1 nuclear magnetic resonance spectrometry. USGS Water Resources Investigations Report 89–4196
Thorn KA (1994) Nuclear-magnetic-resonance studies of fulvic and humic acids from the Suwannee River. In: Humic Substances in the Suwannee River, Georgia: Interactions, properties, and Proposed structures. USGS Water-Supply Paper 2373
Thurman EM (1985) Organic Geochemistry of Natural Waters. Martinus Jijhoff/Dr. W. Junk Publishers
Tranvik L (1993) Microbial transformation of labile dissolved organic matter into humic-like matter in seawater. FEMS Microb. Ecol. 12: 177–183
Vähätalo AV,Salonen K,Salkinoja-Salonen M &Hatakka A (1999) Photochemical mineralization of synthetic lignin in lake water indicates enhanced turnover of aromatic organic matter under solar radiation. Biodegradation 10: 415–420
Valentine RL &Zepp RG (1993) Formation of carbon monoxide from the photodegradation of terrestrial dissolved organic carbon in natural waters. Environ. Sci. Technol. 27: 409-412
Waldron S,Watson-Craik IA,Hall A &Fallick AE (1998) The carbon and hydrogen stable isotopic composition of bacteriogenic methane: A laboratory study using a landfill inoculum. Geomicrob. 15: 157–169
Wetzel RG (1983) Limnology, 2nd Ed. Saunders Publishing, Ft.Worth
Zafiriou OC,Joussot-Dubien J,Zepp RG &Zika RG (1984) Photochemistry of natural waters. Environ. Sci. Technol. 18(2): 358A-371A
Zepp RG (1988) Environmental photoprocesses involving natural organic matter. In: Frimmel FH &Christman RF (Eds) Humic Substances and their Role in the Environment (pp 193–214). J. Wiley & Sons
Zepp RG,Callaghan TV &Erickson DJ (1995) Effects of increased solar ultraviolet radiation on biogeochemical cycles. Ambio. 24: 181–186
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Osburn, C.L., Morris, D.P., Thorn, K.A. et al. Chemical and optical changes in freshwater dissolved organic matter exposed to solar radiation. Biogeochemistry 54, 251–278 (2001). https://doi.org/10.1023/A:1010657428418
Issue Date:
DOI: https://doi.org/10.1023/A:1010657428418