scholarly journals Spatial Variability of Dissolved Organic Carbon, Solutes, and Suspended Sediment in Disturbed Low Arctic Coastal Watersheds

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
C. Coch ◽  
J. L. Ramage ◽  
S. F. Lamoureux ◽  
H. Meyer ◽  
C. Knoblauch ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Spatial Variability ◽  
Suspended Sediment ◽  
Coastal Watersheds ◽  
Low Arctic

scholarly journals Changes in food web dynamics of low Arctic ponds with varying content of dissolved organic carbon

2018 ◽  
Vol 50 (1) ◽  
pp. S100016 ◽  
Author(s):  
Heather L. Mariash ◽  
Matteo Cazzanelli ◽  
Milla Rautio ◽  
Ladislav Hamerlik ◽  
Matthew J. Wooller ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Food Web ◽  
Food Web Dynamics ◽  
Arctic Ponds ◽  
Low Arctic

scholarly journals Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?

2020 ◽  
Vol 24 (4) ◽  
pp. 1709-1720 ◽  
Author(s):  
Stefan W. Ploum ◽  
Hjalmar Laudon ◽  
Andrés Peralta-Tapia ◽  
Lenka Kuglerová
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Spatial Variability ◽  
Boreal Forest ◽  
Management Practices ◽  
Groundwater Chemistry ◽  
Stream Bank ◽  
Small Streams ◽  
Lateral Distance ◽  
Topographic Depressions

Abstract. The riparian zone (RZ), or near-stream area, plays a fundamental role in the biogeochemistry of headwaters. Here, wet, carbon-rich soils can change groundwater chemistry before it enters the stream. In the boreal forest, the RZ plays an especially important role in the export of dissolved organic carbon (DOC) to streams. However, the RZ is not uniform, and spatial variability of riparian groundwater hydrology and chemistry can be large. Terrestrial topographic depressions create hydrological pathways towards focal points in the RZ, which we refer to as “discrete riparian inflow points” (DRIPs). Combining the chemical function of the RZ and the convergence of hydrological pathways, we hypothesize that DRIPs play a disproportionally large role in conveying DOC to small streams. Earlier work has demonstrated that runoff from DRIPs can make up the majority of riparian flow contributions to streams, but it is currently unknown how their groundwater chemistry differs from the rest of the RZ. Therefore, we ask the following question: are DOC concentrations in riparian groundwater linked to hydrological pathways in the boreal forest? To answer this question, we sampled riparian groundwater during six campaigns across three boreal headwater streams in Sweden. The groundwater wells were distributed into 10 DRIP and non-DRIP pairs (60 wells), following transects from the upland (20 m lateral distance from the stream bank) to the near-stream area (<5 m lateral distance from the stream bank). The variability in DOC, pH, and electrical conductivity (EC) was analyzed using linear mixed-effects models (LMMs). We explained the variability using three factors: distance from the stream, seasonality, and DRIP/non-DRIP. Our results showed that DRIPs provided DOC-rich water (34 mg L−1) with relatively low EC (36 µS cm−1). The “non-DRIP” riparian water had 40 % lower DOC concentrations (20 mg L−1) and a 45 % higher EC (52 µS cm−1) on average. Moreover, groundwater chemistry from DRIPs was spatially and temporally relatively homogeneous. In contrast, non-DRIP water transformed distinctly in the last 25 m towards the stream, and the chemical variability was also larger between seasons. We concluded that hydrological pathways and spatial variability in riparian groundwater DOC concentrations are linked, and that DRIPs can be seen as important control points in the boreal landscape. Characterizing DRIPs in headwater catchments can be useful for upscaling carbon inputs in boreal stream ecosystems and for delineating hydrologically adapted buffers for forest management practices.

scholarly journals Summer rainfall dissolved organic carbon, solute, and sediment fluxes in a small Arctic coastal catchment on Herschel Island (Yukon Territory, Canada)

2018 ◽  
Vol 4 (4) ◽  
pp. 750-780 ◽  
Author(s):  
Caroline Coch ◽  
Scott F. Lamoureux ◽  
Christian Knoblauch ◽  
Isabell Eischeid ◽  
Michael Fritz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Suspended Sediment ◽  
Summer Rainfall ◽  
Yukon Territory ◽  
The Arctic ◽  
Rainfall Frequency ◽  
The Future ◽  
Matter Flux

Coastal ecosystems in the Arctic are affected by climate change. As summer rainfall frequency and intensity are projected to increase in the future, more organic matter, nutrients and sediment could be mobilized and transported into the coastal nearshore zones. However, knowledge of current processes and future changes is limited. We investigated streamflow dynamics and the impacts of summer rainfall on lateral fluxes in a small coastal catchment on Herschel Island in the western Canadian Arctic. For the summer monitoring periods of 2014–2016, mean dissolved organic matter flux over 17 days amounted to 82.7 ± 30.7 kg km−2 and mean total dissolved solids flux to 5252 ± 1224 kg km−2. Flux of suspended sediment was 7245 kg km−2 in 2015, and 369 kg km−2 in 2016. We found that 2.0% of suspended sediment was composed of particulate organic carbon. Data and hysteresis analysis suggest a limited supply of sediments; their interannual variability is most likely caused by short-lived localized disturbances. In contrast, our results imply that dissolved organic carbon is widely available throughout the catchment and exhibits positive linear relationship with runoff. We hypothesize that increased projected rainfall in the future will result in a similar increase of dissolved organic carbon fluxes.

scholarly journals A Semi-Analytical Optical Remote Sensing Model to Estimate Suspended Sediment and Dissolved Organic Carbon in Tropical Coastal Waters Influenced by Peatland-Draining River Discharges off Sarawak, Borneo

2020 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Nagur Cherukuru ◽  
Patrick Martin ◽  
Nivedita Sanwlani ◽  
Aazani Mujahid ◽  
Moritz Müller
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Suspended Sediment ◽  
Coastal Water ◽  
Coastal Waters ◽  
Suspended Sediments ◽  
Optical Remote Sensing ◽  
Coastal Water Quality

Coastal water quality degradation is a global challenge. Marine pollution due to suspended sediments and dissolved matter impacts water colour, biogeochemistry, benthic habitats and eventually human populations that depend on marine resources. In Sarawak (Malaysian Borneo), peatland-draining river discharges containing suspended sediments and dissolved organic carbon influence coastal water quality at multiple locations along the coast. Optical remote sensing is an effective tool to monitor coastal waters over large areas and across remote geographic locations. However, the lack of regional optical measurements and inversion models limits the use of remote sensing observations for water quality monitoring in Sarawak. To overcome this limitation, we have (1) compiled a regional spectral optical library for Sarawak coastal waters, (2) developed a new semi-analytical remote sensing model to estimate suspended sediment and dissolved organic carbon in coastal waters, and (3) demonstrated the application of our remote sensing inversion model on satellite data over Sarawak. Bio-optical data analysis revealed that there is a clear spatial variability in the inherent optical properties of particulate and dissolved matter in Sarawak. Our optical inversion model coupled with the Sarawak spectral optical library performed well in retrieving suspended sediment (bias = 3% and MAE = 5%) and dissolved organic carbon (bias = 3% and MAE = 8%) concentrations. Demonstration products using MODIS Aqua data clearly showed the influence of large rivers such as the Rajang and Lupar in discharging suspended sediments and dissolved organic carbon into coastal waters. The bio-optical parameterisation, optical model, and remote sensing inversion approach detailed here can now help improve monitoring and management of coastal water quality in Sarawak.

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