Low biodegradability of dissolved organic matter and trace metals from subarctic waters

Olga V Oleinikova; Liudmila S Shirokova; Olga Y Drozdova; Sergey A Lapitskiy; Oleg S Pokrovsky

doi:10.1016/j.scitotenv.2017.10.340

Low biodegradability of dissolved organic matter and trace metals from subarctic waters

Sci Total Environ. 2018 Mar 15:618:174-187. doi: 10.1016/j.scitotenv.2017.10.340. Epub 2017 Nov 9.

Authors

Olga V Oleinikova¹, Liudmila S Shirokova², Olga Y Drozdova³, Sergey A Lapitskiy³, Oleg S Pokrovsky⁴

Affiliations

¹ GET (Geosciences and Environment Toulouse) UMR 5563 CNRS, University Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France; Geological Faculty, Moscow State University, 1 Leninskie Gory, 119234 Moscow, Russia.
² GET (Geosciences and Environment Toulouse) UMR 5563 CNRS, University Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France; N. Laverov Federal Center for Integrated Arctic Research; IEPS, Russian Academy of Science, 23 Nab. Severnoi Dviny, 163000 Arkhangelsk, Russia.
³ Geological Faculty, Moscow State University, 1 Leninskie Gory, 119234 Moscow, Russia.
⁴ GET (Geosciences and Environment Toulouse) UMR 5563 CNRS, University Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France. Electronic address: oleg.pokrovsky@get.omp.eu.

PMID: 29128766
DOI: 10.1016/j.scitotenv.2017.10.340

Abstract

The heterotrophic mineralization of dissolved organic matter (DOM) controls the CO₂ flux from the inland waters to the atmosphere, especially in the boreal waters, although the mechanisms of this process and the fate of trace metals associated with DOM remain poorly understood. We studied the interaction of culturable aquatic (Pseudomonas saponiphila) and soil (Pseudomonas aureofaciens) Gammaproteobacteria with seven different organic substrates collected in subarctic settings. These included peat leachate, pine crown throughfall, fen, humic lake, stream, river, and oligotrophic lake with variable dissolved organic carbon (DOC) concentrations (from 4 to 60mgL^-1). The highest removal of DOC over 4days of reaction was observed in the presence of P. aureofaciens (33±5%, 43±3% and 53±7% of the initial amount in fen water, humic lake and stream, respectively). P. saponiphila degraded only 5% of DOC in fen water but did not affect all other substrates. Trace elements (TE) were essentially controlled by short-term (0-1h) adsorption on the surface of cells. Regardless of the nature of organic substrate and the identity of bacteria, the degree of adsorption ranged from 20 to 60% for iron (Fe³⁺), 15 to 55% for aluminum (Al), 10 to 60% for manganese (Mn), 10 to 70% for nickel (Ni), 20 to 70% for copper (Cu), 10 to 60% for yttrium (Y), 30 to 80% for rare earth elements (REE), and 15 to 50% for uranium (U^VI). Rapid adsorption of organic and organo-mineral colloids on bacterial cell surfaces is novel and potentially important process, which deserves special investigation. The long-term removal of dissolved Fe and Al was generally consistent with solution supersaturation degree with respect to Fe and Al hydroxides, calculated by visual Minteq model. Overall, the biomass-normalized biodegradability of various allochthonous substrates by culturable bacteria is much lower than that of boreal DOM by natural microbial consortia.

Keywords: Adsorption; Biodegradation; Boreal; Coagulation; Dissolved organic carbon; Trace elements.

MeSH terms

Adsorption
Bacteria / metabolism*
Biodegradation, Environmental*
Carbon
Fresh Water / chemistry*
Lakes
Microbial Consortia
Russia
Soil
Soil Microbiology
Trace Elements / metabolism*
Water Microbiology

Substances

Soil
Trace Elements
Carbon