THE ORGANIC COMPONENT OF PARTICULATE MATTER IN SMALL STREAMS OF THE NORTHERN YENISEI REGION DURING THE SUMMER-AUTUMN PERIOD
N. I. TANANAEV1,2,3, L. S. LEBEDEVA1,4
1Melnikov Permafrost Institute, Siberian Branch, Russian Academy of Sciences, ul. Merzlotnaya, 36, Yakutsk, 677010, Russia
nikita.tananaev@gmail.com
2Yugra Research Institute of Information Technologies, ul. Mira, 151, Khanty-Mansiisk, 628010, Russia
3L’UniversitГ©de Toulouse, Avenue de l’Agrobiopole BP 32607, Castanet-Tolosan, Cedex, 31326, France
4State Hydrological Institute of Roshydromet, Vtoraya Liniya Vasil’evskogo Ostrova, 23, St. Petersburg, 199053, Russia
lyudmlalebedeva@gmail.com
Keywords: взвешенные наносы, взвешенное органическое вещество, взвешенный углерод, тундрово-таежная зона, Енисейский Север, suspended sediment, particulate organic matter, particulate organic carbon, tundra-taiga transition zone, Northern Yenisei region
Abstract
A quantitative assessment is made of suspended sediment load, including particulate organic matter and organic carbon, in 2014 for the small streams of the Northern Yenisei region, in the taiga-tundra transition zone (near the city of Igarka, Krasnoyarsk krai). It was found that the suspended sediment concentration (SSC) of the streams under investigation fluctuated between 2 and 18 mg/L during the summer-autumn low-water period of 2014. The proportion of particulate organic matter (POM) in the total sediment yield varied from 16.4 to 74.1 %, depending on landscape-geomorphological conditions for suspended sediment formation: it is higher for streams with tundra catchments and lower on forest watersheds underlain by sandy and clayey loams. The POM content varies from catchment to catchment from 1.63 to 2.42 mg/L, and the mean concentration of particulate or ganic carbon (POC) is estimated at 0.73 to 1.09 mg C/L. It is shown that the local channel transformations serve as the main source of POM and POC input to the water of two out of three streams under study. Surface runoff or fast subsurface flow in the organic soil horizon is the external source of POM input to the water of the third stream during flooding. Regional empirical dependencies were obtained, which correlate the water discharge, total SSC and the proportion of POM are obtained. The long-term proportion of POM in the annual suspended sediment flow of the Graviyka river makes up 25 % and POC, 11 %, or, in absolute values, 406 and 183 t/year, and in units of layer 1.26 and 0.57 t/km 2 , respectively.
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