Integrating remote sensing of hydrological processes and dissolved organic carbon fluxes in long-term Lake Studies

Dissolved organic carbon (DOC) is an important fraction of organic carbon (OC) that together with colored dissolved organic matter (CDOM) plays a key role in the carbon cycling of lakes. Lake Vo similar to rtsja center dot rv is a large and shallow eutrophic lake where water quality measurements have been carried out for a long time. The monthly characteristics of DOC and CDOM in Vo similar to rtsja center dot rv and its input/output rivers were traced in 5-years observations. We attempted to link the hydro-morphological indices as lake area (A), water level (WL) and volume variations (Qc) with lake DOC fluxes and CDOM-DOC relationships to improve understanding of carbon fluxes in a very shallow, large and highly eutrophic lake, as well as of the possibility to estimate DOC fluxes by CDOM via remote sensing. The research questions were: how the properties and quantity of DOC, its fluxes and CDOM-DOC relationship in a very shallow, large and highly eutrophic lake are responding to 1) variable proportions of allochthonous and autochthonous processes and 2) changing hydrological conditions. The increased lake volume variation in spring caused the higher level of CDOM, signifying the terrestrial (allochthonous) DOC (DOCAlloch) domination in Lake Vo similar to rtsja center dot rv. The proportion of DOCAlloch increased together with increasing WL, A and CDOM concentration. Although the generally high proportion of DOCAlloch in Vo similar to rtsja center dot rv, the autochthonous DOC determines the water color (CDOM/DOC) in this highly productive ecosystem with short residence time (280-365 days). Our study on DOC flux revealed that the internal carbon sources, driven by hydrological factors, contribute significantly to the role of large and shallow lakes in global carbon cycling. The further development of water color remote sensing could provide novel directions for understanding the feedbacks of lake DOC flux and changing hydrology.

Automated summary

The study monitored changes in DOC and CDOM in Lake Vo similar to rtsja center dot rv and its input/output rivers, finding that increased lake volume in spring led to higher CDOM levels, indicating the dominance of terrestrial DOC in the lake. Despite the high proportion of terrestrial DOC, autochthonous DOC determines water color, impacting carbon flux and hydrological changes.