scholarly journals Dissolved organic matter concentration changes in river waters of Latvia

2011 ◽  
Vol 65 (1-2) ◽  
pp. 40-47
Author(s):  
Māris Kļaviņš ◽  
Ilga Kokorīte ◽  
Valērijs Rodinovs
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Bodies ◽  
Biological Processes ◽  
River Waters ◽  
Organic Matter Concentration ◽  
Concentration Changes ◽  
The Impact ◽  
Matter Concentration

Dissolved organic matter concentration changes in river waters of Latvia Amounts of natural organic matter in surface waters reflect the character and intensity of biological processes in water bodies, human impact and depend on the physico-geographical environment and land-use in the catchments. Thus, analysis of the concentrations and loadings of organic substances to adjacent water bodies can be used to indicate environmental change and human impacts. This study revealed significant increasing trends of total organic carbon (TOC) and water colour in most of the studied Latvian rivers during the last decade. However, over longer time periods, there have been pronounced oscillations of TOC concentrations, stressing the importance of long-term changes of river discharge. On a yearly basis, there was a positive correlation between parameters of organic matter concentration and discharge in all selected rivers. The impact of discharge on concentrations of organic matter can be masked by other factors, such as changes in precipitation, biological processes, soil types and land-use.

Natural organic matter export from boreal catchments (the Salaca River basin, Latvia) and its influencing factors

2012 ◽  
Vol 43 (4) ◽  
pp. 330-340 ◽  
Author(s):  
Maris Klavins ◽  
Ilga Kokorite ◽  
Linda Eglite ◽  
Valery Rodinov
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
River Basin ◽  
Natural Organic Matter ◽  
Organic Matter Concentration ◽  
Runoff Regime ◽  
Discharge Regime ◽  
Type Of Land Use ◽  
The Impact ◽  
Matter Concentration

A noteworthy increase in the organic matter concentration and export, as well as water colour, in the catchments of the Salaca River has been observed during the last decades. This study investigates factors behind this increase: the impact of climate, land use and human loading changes on the concentrations and export of the organic matter in the Salaca River/Lake Burtnieks catchments. Proportion of wetlands in the river basin, type of land use, and runoff regime can be considered as the main factors influencing the organic carbon loadings. Despite a steady overall tendency of increase, considerable oscillations of organic matter loadings influenced by the changes in the river discharge regime were observed for extended periods of time.

scholarly journals Megafire affects stream sediment flux and dissolved organic matter reactivity, but land use dominates nutrient dynamics in semiarid watersheds

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257733
Author(s):  
Trevor Crandall ◽  
Erin Jones ◽  
Mitchell Greenhalgh ◽  
Rebecca J. Frei ◽  
Natasha Griffin ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Extreme Precipitation ◽  
Fold Increase ◽  
Sediment Flux ◽  
Nutrient Concentrations ◽  
Human Influence ◽  
Organic Matter Concentration ◽  
Matter Concentration

Climate change is causing larger wildfires and more extreme precipitation events in many regions. As these ecological disturbances increasingly coincide, they alter lateral fluxes of sediment, organic matter, and nutrients. Here, we report the stream chemistry response of watersheds in a semiarid region of Utah (USA) that were affected by a megafire followed by an extreme precipitation event in October 2018. We analyzed daily to hourly water samples at 10 stream locations from before the storm event until three weeks after its conclusion for suspended sediment, solute and nutrient concentrations, water isotopes, and dissolved organic matter concentration, optical properties, and reactivity. The megafire caused a ~2,000-fold increase in sediment flux and a ~6,000-fold increase in particulate carbon and nitrogen flux over the course of the storm. Unexpectedly, dissolved organic carbon (DOC) concentration was 2.1-fold higher in burned watersheds, despite the decreased organic matter from the fire. DOC from burned watersheds was 1.3-fold more biodegradable and 2.0-fold more photodegradable than in unburned watersheds based on 28-day dark and light incubations. Regardless of burn status, nutrient concentrations were higher in watersheds with greater urban and agricultural land use. Likewise, human land use had a greater effect than megafire on apparent hydrological residence time, with rapid stormwater signals in urban and agricultural areas but a gradual stormwater pulse in areas without direct human influence. These findings highlight how megafires and intense rainfall increase short-term particulate flux and alter organic matter concentration and characteristics. However, in contrast with previous research, which has largely focused on burned-unburned comparisons in pristine watersheds, we found that direct human influence exerted a primary control on nutrient status. Reducing anthropogenic nutrient sources could therefore increase socioecological resilience of surface water networks to changing wildfire regimes.

scholarly journals Hydrophysical research in the Kruglaya Bay (Sevastopol)

2021 ◽  
Author(s):  
A. A. Latushkin ◽  
A. I. Chepyzhenko ◽  
A. V. Prazukin ◽  
A. A. Chepyzhenko ◽  
Yu. K. Firsov ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Suspended Matter ◽  
Water Layer ◽  
Water Area ◽  
Matter Content ◽  
Total Suspended Matter ◽  
Dynamic Activity ◽  
Organic Matter Concentration ◽  
Matter Concentration

On the basis of two hydrophysical surveys (August 28 and November 14, 2019), the spatial distribution was investigated of temperature, salinity, total suspended matter, dissolved organic matter features, and total suspended matter dynamic activity in the waters of the Kruglaya Bay. The horizontal and vertical distributions of these characteristics were considered. The hydrophysical parameters were measured from a small vessel at anchored stations using Kondor Sounding Complex. The analysis of obtained distributions showed that less saline and more turbid waters were observed in the apex of the bay. The highest content of suspended particles and dissolved organic matter were detected in this water area. An almost uniform stratification of hydrological parameters and total suspended matter concentration were observed in the vertical distribution over the entire water area of the bay. In the vertical dissolved organic matter distribution, an increase under the water surface layer of ~ 1–5 m was observed both in August and in November. This layer was more pronounced in November. The total suspended matter content in the surface water layer in August 2019 was on average twice as high as in November of the same year, and the dissolved organic matter concentration was lower.

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