https://vital.lib.tsu.ru/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133263 Wed 24 Apr 2024 10:14:15 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133266 Wed 24 Apr 2024 10:07:12 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133267 50% of the annual export of DOC and generally insoluble trace metals. However, the winter baseflow provided sizable proportions of mobile elements such as DIC, major anions, cations, alkaline-earth elements, trace oxyanions and uranium. The size distribution of riverine solutes demonstrated 20–50% of DOC in the colloidal (3 kDa – 0.45 μm) form, dominance of low molecular forms (< 3 kDa) of soluble elements (alkali, alkaline earths, anions and neutral molecules) and essentially colloidal status of divalent metals (Cu, Zn, Cd, Pb, Ni), trivalent and tetravalent hydrolysates and U (from 30 to 93%). Seasonal variations in colloidal fractions of riverine solutes were consistent with the main mechanisms of element mobilization from the watershed to the Pechora River, as reflected in the 3 groups of elements according to their concentration – discharge relationship. Based on the present study and results of other mid-sized Arctic rivers (Severnaya Dvina, Taz), we demonstrate that mean discharges and solute concentrations in August can be used to adequately (± 20%) approximate mean annual values, hence allowing annual flux assessment via single month sampling campaign. A comparison of contemporary yields of Ca, Mg, Cl, SO4, DIC and DOC against historical data for the Pechora River basin demonstrated reasonable agreement within the inter-annual variations that is consistent with long-term data series on other Arctic rivers.]]> Wed 24 Apr 2024 10:00:15 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:000996393 Tue 14 Feb 2023 15:56:41 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133426 Thu 25 Apr 2024 10:16:12 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133429 0.90; p < 0.05) with Si associated with amorphous Fe and Al compounds and soluble bioavailable Si extracted using CaCl2 method, but negatively correlated with total Si content in soils and Si of phytoliths. The main pools of soil labile Si could be allophanes, organo-Fe-Al-Si compounds and adsorbed forms of Si onto Fe and Al hydroxides. We hypothesize that, because of low sensibility of RSi to type of soil and fluid pH, the majority of soils regulate Si release at some ‘universal’ rate which is further reflected in relatively narrow range of riverine Si concentrations and export fluxes across the world. Therefore, the modeling of chemical weathering and element export flux in the watersheds should incorporate the experimentally measured reactivity of the whole soil rather than individual constituting primary or secondary minerals.]]> Thu 25 Apr 2024 10:02:13 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133427 Thu 25 Apr 2024 10:02:13 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133430 Thu 25 Apr 2024 09:55:13 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133432 80 times) impoverished compared with UCC and RSM. Taken together, the elemental composition of macroaggregates allows for distinguishing the lithogenic and biogenic impacts on the occurrence of these unique large-scale mucilage events, linked to the exometabolism of marine plankton combined with the input of allochthonous inorganic material.]]> Thu 25 Apr 2024 09:48:16 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001133433 Thu 25 Apr 2024 09:48:13 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001009378 Thu 16 Nov 2023 11:51:51 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001009377 30 %, regardless of season) variations between day and night. The CH4 concentrations and fluxes increased in the order “spring ≤ summer < autumn” and ranged from 1 to 15 μmol L−1 and 5 to 100 mmol m−2 d−1, respectively. The CO2 concentrations and fluxes (range from 100 to 400 μmol L−1 and 1 to 4 g C m−2 d−1, respectively) were positively correlated with dissolved and particulate organic carbon, total nitrogen and bacterial number of the water column. The CH4 concentrations and fluxes were positively correlated with phosphate and ammonia concentrations. Of the landscape parameters, positive correlations were detected between riparian vegetation biomass and CO2 and CH4 concentrations. Over the six-month open-water period, areal emissions of C (>99.5 % CO2; <0.5 % CH4) from the watersheds of 11 rivers were equal to the total downstream C export in this part of the WSL. Based on correlations between environmental controllers (watershed land cover and the water column parameters), we hypothesize that the fluxes are largely driven by riverine mineralization of terrestrial dissolved and particulate OC, coupled with respiration at the river bottom and riparian sediments. It follows that, under climate warming scenario, most significant changes in GHG regimes of western Siberian rivers located in permafrost-free zone may occur due to changes in the riparian zone vegetation and water coverage of the floodplains.]]> Thu 16 Nov 2023 11:51:49 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001008915 Thu 09 Nov 2023 09:56:04 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001067505 Thu 08 Feb 2024 10:56:19 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001139591 Mon 27 May 2024 15:57:04 KRAT ]]> https://vital.lib.tsu.ru/vital/access/manager/Repository/koha:001015007 Mon 04 Dec 2023 10:16:28 KRAT ]]>