Global Scale Fluorescence Characterization Of Dissolved Organic Matter In Alpine And Remote Lakes

MLADENOV, N., MORALES-BAQUERO, R., SOMMARUGA, R., CAMARERO, L., LAURION, I., DIÉGUEZ, M. C. & RECHE, I.

Niza

Congreso; ASLO 2009; 2009

American Society of Limnology and Oceanography

Due to their position in the landscape, alpine and remote lakes provide essential “end member” biogeochemical information without the confounding effects of diverse terrestrial inputs and local anthropogenic pollution. Here we take advantage of a global network of remote lakes (ECOSENSOR) to examine dissolved organic matter (DOM) in lakes of the Atlas Mountains (Morocco), the Sierra Nevada and Pyrenees (Spain), the Alps (Austria), the Patagonian Andes (Argentina), and the Canadian Arctic. Using PARAFAC modeling of fluorescence spectra, we found that the most remote alpine lakes exhibited high protein-like fluorescence, lack of a distinct humic peak (excitation/ emission 350/420-480nm), and low fluorescence at high excitation wavelengths. We further evaluated the influence of Saharan dust deposition on lake DOM and found that, across a gradient of low to high deposition (Austria-Morocco), there was an increase in DOC, absorption coefficients, and fluorescence intensity. In light of rising desertification linked to global change, these results suggest that atmospheric dust deposition may be an important, yet thus far unrecognized control on lake DOM dynamics and that remote lakes provide a unique opportunity to monitor this influence.