Integrated source identification of particulate and dissolved organic matter related to anthropogenic activities in an artificial lake system

Abstract

We investigated stable isotopic composition of particulate and dissolved organic matter (OM) to identify OM sources within artificial lake system (Lake Sihwa) surrounded by various land-use types. Spatial variations of hydrochemical components showed significant differences between pre- and post-typhoon. Together with varied POC/PN ratios (1.2-145) in the POM fractions, stable isotopic signatures of POC and PN were shifted to depleted patterns after typhoon events, reflecting the increased anthropogenic sources derived from industrial sections. In addition, DOC/DON ratios were more decreased (2.3 +/- 1.8) during post-typhoon suggesting increased terrestrial inputs. The isotopic signatures of DOM fractions showed homogeneous patterns in the water column of Lake Sihwa, indicating substantial transports of sewage within industry and urban. Our integrated interpretation based on stable isotopic composition and stoichiometry of POM and DOM, can be useful approach to understand the OM cycles, providing fundamental insight to manage water quality and biological resources under extreme climate.