| Abstract | Little is known about the quantity and quality of dissolved organic matter (DOM) in waters from continental geothermal systems, with only a few reports available from the Yellowstone US National Park. In this study, we explored the chemodiversity of DOM in water samples collected from two geothermal hot springs from the Kenyan East African Rift Valley, a region extremely rich in fumaroles, geysers, and spouting springs, located in close proximity to volcanic lakes. The DOM characterization included in-depth assessments performed by negative electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Reduced, saturated and little aromatic DOM compounds were dominant in the hot spring waters collected from either the Ol Njorowa gorge (ON) or the south shore of the soda-saline Lake Elementaita (ELM). Oxygen-poor and sulfur-bearing DOM molecules prevailed in ON, probably reflecting abiotic sulfurization from sulfide-rich geofluids. Nitrogen-bearing aliphatic and protein-like molecules were abundant in ELM, possibly perfusing through the organic-rich sediments of the adjacent Lake Elementaita. Notably, the heat-altered DOM of ancient autochthonous derivation could represent an overlooked source of aliphatic organic carbon for connected lentic environments, with a potential direct impact on nutrient cycling in lakes that receive geothermal water inputs. |
| Authors | Butturini A.[1], Amalfitano S.[2], Herzsprung P.[3], Lechtenfeld O.J.[4], Venturi S.[5], Olaka L.A.[6], Pacini N.[7], Harper D.M.[8,9], Tassi F.[5,10], Fazi S.[2] |
| Text | 448057 2020 10.3390/w12123512 ISI Web of Science WOS 000603499400001 DOM FT ICR MS hot springs East African Rift Valley Kenya Dissolved Organic Matter in Continental Hydro Geothermal Systems Insights from Two Hot Springs of the East African Rift Valley Butturini A. 1 , Amalfitano S. 2 , Herzsprung P. 3 , Lechtenfeld O.J. 4 , Venturi S. 5 , Olaka L.A. 6 , Pacini N. 7 , Harper D.M. 8,9 , Tassi F. 5,10 , Fazi S. 2 1 Department de Biologia evolutiva, Ecologia y Ciencies ambientals, Universitat de Barcelona, 08028 Barcelona, Spain; 2 Water Research Institute IRSA CNR , Via Salaria km 29.300 CP10, 00015 Monterotondo, Rome, Italy; 3 Department Lake Research, Helmholtz Centre for Environmental Research UFZ , 39114 Magdeburg, Germany; 4 Department Analytical Chemistry, Research Group BioGeoOmics, Helmholtz Centre for Environmental Research UFZ , 04318 Leipzig, Germany; 5 Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence, Italy; 6 Department of Geology, University of Nairobi, P.O Box 30197, Nairobi 00100, Kenya; 7 Department of Environmental Engineering, University of Calabria, 87036 Arcavacata di Rende CS , Italy; 8 University of Leicester, Leicester LE1 7RH, UK; 9 Freshwater Biological Association, Ambleside LA22 0LP, UK; 10 Institute of Geosciences and Earth Resources IGG CNR , Via G. La Pira 4, 50121 Florence, Italy Little is known about the quantity and quality of dissolved organic matter DOM in waters from continental geothermal systems, with only a few reports available from the Yellowstone US National Park. In this study, we explored the chemodiversity of DOM in water samples collected from two geothermal hot springs from the Kenyan East African Rift Valley, a region extremely rich in fumaroles, geysers, and spouting springs, located in close proximity to volcanic lakes. The DOM characterization included in depth assessments performed by negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry FT ICR MS . Reduced, saturated and little aromatic DOM compounds were dominant in the hot spring waters collected from either the Ol Njorowa gorge ON or the south shore of the soda saline Lake Elementaita ELM . Oxygen poor and sulfur bearing DOM molecules prevailed in ON, probably reflecting abiotic sulfurization from sulfide rich geofluids. Nitrogen bearing aliphatic and protein like molecules were abundant in ELM, possibly perfusing through the organic rich sediments of the adjacent Lake Elementaita. Notably, the heat altered DOM of ancient autochthonous derivation could represent an overlooked source of aliphatic organic carbon for connected lentic environments, with a potential direct impact on nutrient cycling in lakes that receive geothermal water inputs. 12 Published version https //www.mdpi.com/ Dissolved Organic Matter in Continental Hydro Geothermal Systems Insights from Two Hot Springs... BUTTURINI_December_2020.pdf Articolo in rivista National Water Council 0305 3105 Water Lond. 1974 Water Lond. 1974 Water Lond. 1974 Water. Lond. 1974 francotassi TASSI FRANCO VENTURI STEFANIA stefano.fazi FAZI STEFANO stefano.amalfitano AMALFITANO STEFANO |
