Novel comprehensive field-based monitoring dataset of largest Siberian river particulate flux into Arctic ocean

2020 ◽  
Author(s):  
Sergey Chalov ◽  
Nikolay Kasimov
Keyword(s):  
Arctic Ocean ◽  
Depth Profile ◽  
River Mouth ◽  
Sampling Strategy ◽  
Acoustic Doppler Current Profiler ◽  
The Arctic ◽  
Quality Data ◽  
Hydraulic Control ◽  
Sediment Depth ◽  
Siberian River

<p>Northern rivers transport huge quantities of water and constituents from the continents to the Arctic Ocean. Characteristics of the transport mode of chemical flow are poorly monitored, and the existing estimates of river flux are characterized by high uncertainty. Since 2018, the monitoring campaign ArcticFlux has been sampling the 4 largest Siberian rivers (Ob, Enisey, Lena and Kolyma) multiple times per year at the most downstream river crossection selected as unaffected by river mouth processes (tides, surges etc).  Using Acoustic Doppler Current Profiler (ADCP) acquisitions with sediment depth profile sampling we build a simple model to derive the bed and suspended seasonal fluxes, grain size and particulate heavy metals distributions. Study demonstrates the significance of the hydraulic control for the metal partitioning within river as well as explains spatial (inter-basin) variations in particulate flux due to local hydrology, erosion rates and catchment lithology. Using (ADCP) acquisitions with sediment depth profile sampling of the Ob, Enisey, Lena and Kolyma, we aim to build a model to derive the annual flux of the sediments and particulate flux of the selected metals.  The datasets is also used to assess the uncertainties in selected sediment quantity and quality data, including contributions from vertical and crossectional variations into fluxes estimates including requirements for sampling strategy. Based on the modeling techniques and application of erosion models for all four Arctic catchments the project will also focus on the novel quantitative assessment of bank and catchment erosion contribution into chemical flux.</p>

scholarly journals Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea

2019 ◽  
Vol 16 (6) ◽  
pp. 1305-1319 ◽  
Author(s):  
Sarah Conrad ◽  
Johan Ingri ◽  
Johan Gelting ◽  
Fredrik Nordblad ◽  
Emma Engström ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Salinity Gradient ◽  
River Mouth ◽  
The Arctic ◽  
Shelf Zone ◽  
Laptev Sea ◽  
Lena River ◽  
Freshwater Plume ◽  
The Laptev Sea ◽  
Particles And Colloids

Abstract. Riverine Fe input is the primary Fe source for the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate (>0.22 µm), colloidal (0.22 µm–1 kDa), and truly dissolved (<1 kDa) fractions of Fe was carried out. The total Fe concentrations ranged from 0.2 to 57 µM with Fe dominantly as particulate Fe. The loss of >99 % of particulate Fe and about 90 % of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative δ56Fe values (relative to IRMM-14). The colloidal Fe phase showed negative δ56Fe values close to the river mouth (about −0.20 ‰) and positive δ56Fe values in the outermost stations (about +0.10 ‰). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative δ56Fe values, representing chemically reactive ferrihydrites. The positive δ56Fe values of the colloidal phase within the outer Lena River freshwater plume might represent Fe oxyhydroxides, which remain in the water column, and will be the predominant δ56Fe composition in the Arctic Ocean.

scholarly journals Separating individual contributions of major Siberian rivers in the Transpolar Drift of the Arctic Ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ronja Paffrath ◽  
Georgi Laukert ◽  
Dorothea Bauch ◽  
Michiel Rutgers van der Loeff ◽  
Katharina Pahnke
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Lateral Separation ◽  
Central Arctic Ocean ◽  
Siberian River ◽  
Neodymium Isotopes ◽  
The Arctic Ocean ◽  
Individual Contributions ◽  
Transpolar Drift ◽  
The Individual

AbstractThe Siberian rivers supply large amounts of freshwater and terrestrial derived material to the Arctic Ocean. Although riverine freshwater and constituents have been identified in the central Arctic Ocean, the individual contributions of the Siberian rivers to and their spatiotemporal distributions in the Transpolar Drift (TPD), the major wind-driven current in the Eurasian sector of the Arctic Ocean, are unknown. Determining the influence of individual Siberian rivers downstream the TPD, however, is critical to forecast responses in polar and sub-polar hydrography and biogeochemistry to the anticipated individual changes in river discharge and freshwater composition. Here, we identify the contributions from the largest Siberian river systems, the Lena and Yenisei/Ob, in the TPD using dissolved neodymium isotopes and rare earth element concentrations. We further demonstrate their vertical and lateral separation that is likely due to distinct temporal emplacements of Lena and Yenisei/Ob waters in the TPD as well as prior mixing of Yenisei/Ob water with ambient waters.

scholarly journals Arctic Sea Ice and Freshwater Changes Driven by the Atmospheric Leading Mode in a Coupled Sea Ice–Ocean Model

2003 ◽  
Vol 16 (13) ◽  
pp. 2159-2177 ◽  
Author(s):  
Xiangdong Zhang ◽  
Moto Ikeda ◽  
John E. Walsh
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Siberian River ◽  
The North ◽  
New Findings ◽  
Arctic Sea ◽  
The Arctic Ocean

Abstract Observational and modeling studies have indicated recent large changes of sea ice and hydrographic properties in the Arctic Ocean. However, the observational database is sufficiently sparse that the mechanisms responsible for the recent changes are not fully understood. A coupled Arctic ocean–sea ice model forced by output from the NCEP–NCAR reanalysis is employed to investigate the role that the leading atmospheric mode has played in the recent changes of the Arctic Ocean. A modified Arctic Oscillation (AO) index is derived for the region poleward of 62.5°N in order to avoid ambiguities in the distinction between the conventional AO and the North Atlantic Oscillation index. The model results indicate that the AO is the driver of many of the changes manifested in the recent observations. The model shows reductions of Arctic sea ice area and volume by 3.2% and 8.8%, respectively, when the AO changes from its negative to its positive phase. Concurrently, freshwater storage decreases by about 2%, while the sea ice and freshwater exports via Fram Strait increase substantially. The changes of sea ice and freshwater storage are strikingly asymmetric between the east and the west Arctic. Notable new findings include 1) the interaction of the dynamic and thermodynamic responses in the sense that changes of sea ice growth and melt are driven by, and feed back negatively to, the dynamically (transport) driven changes of sea ice volume; and 2) the compatibility of the associated freshwater changes with recently observed changes in the salinity of the upper Arctic Ocean, thereby explaining the observed salinity variations by a mechanism that is distinct from, but complementary to, the altered circulation of Siberian river water. In addition, the enhanced freshwater export could be a contributing factor to the increased salinity in the Arctic Ocean. The results of the simulations indicate that Arctic sea ice and freshwater distributions change substantially if one phase of the AO predominates over a decadal timescale. However, such results are based on an idealization of the real-world situation, in which the pattern of forcing varies interannually and the number of positive-AO years varies among decades.

scholarly journals Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea

2018 ◽  
Author(s):  
Sarah Conrad ◽  
Johan Ingri ◽  
Johan Gelting ◽  
Fredrik Nordblad ◽  
Emma Engström ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Salinity Gradient ◽  
River Mouth ◽  
The Arctic ◽  
Shelf Zone ◽  
Laptev Sea ◽  
Lena River ◽  
Freshwater Plume ◽  
The Laptev Sea ◽  
Particles And Colloids

Abstract. Riverine Fe input is the primary Fe source to the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate (> 0.22 µm), colloidal (0.22 µm–1 kDa), and truly dissolved ( 99 % of particulate Fe and about 90 % of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative δ56Fe values (relative to IRMM-14). The colloidal Fe phase showed negative δ56Fe values close to the river mouth (about −0.20 ‰) and positive δ56Fe values in the outermost stations (about +0.10 ‰). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative δ56Fe values, representing chemically reactive ferrihydrites. While the positive δ56Fe values of the colloidal phase within the outer Lena River freshwater plume, might represent Fe-oxyhydroxides, which remain in the water column, and will be the predominant δ56Fe composition in the Arctic Ocean.

scholarly journals Remote sensing the dynamics of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean)

2012 ◽  
Vol 9 (4) ◽  
pp. 5205-5248 ◽  
Author(s):  
D. Doxaran ◽  
J. Ehn ◽  
S. Bélanger ◽  
A. Matsuoka ◽  
S. Hooker ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Organic Carbon ◽  
Arctic Ocean ◽  
Satellite Data ◽  
Canadian Arctic ◽  
River Mouth ◽  
Optical Measurements ◽  
The Arctic ◽  
Ocean Colour ◽  
Mackenzie River

Abstract. Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. A direct consequence is an increase in Arctic river discharge with an expectation of increased delivery of organic carbon sequestered in high-latitute soils since the last glacial maximum. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed to an operational stage. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC:SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is validated based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone within which terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work require the validation of the developed SPM regional algorithm based on match-ups with field measurements, then the routine application to ocean colour satellite data in order to better estimate the fluxes and fate of SPM and POC delivered by the Mackenzie River to the Arctic Ocean.

scholarly journals Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing

2012 ◽  
Vol 9 (8) ◽  
pp. 3213-3229 ◽  
Author(s):  
D. Doxaran ◽  
J. Ehn ◽  
S. Bélanger ◽  
A. Matsuoka ◽  
S. Hooker ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Organic Carbon ◽  
Arctic Ocean ◽  
Satellite Data ◽  
Canadian Arctic ◽  
River Mouth ◽  
The Arctic ◽  
Ocean Colour ◽  
The Arctic Ocean ◽  
Mackenzie River

Abstract. Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work will require the validation of the developed SPM regional algorithm based on match-ups with field measurements, then the routine application to ocean colour satellite data in order to better estimate the fluxes and fate of SPM and POC delivered by the Mackenzie River to the Arctic Ocean.

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