scholarly journals Influence of Drying and Wildfire on Longitudinal Chemistry Patterns and Processes of Intermittent Streams

2020 ◽  
Vol 2 ◽  
Author(s):  
Ruth B. MacNeille ◽  
Kathleen A. Lohse ◽  
Sarah E. Godsey ◽  
Julia N. Perdrial ◽  
Colden V. Baxter
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Carbon Sources ◽  
Canopy Cover ◽  
Stream Chemistry ◽  
Intermittent Streams ◽  
Temporal Shift ◽  
Mean Values ◽  
Stream Drying ◽  
Patterns And Processes

Stream drying and wildfire are projected to increase with climate change in the western United States, and both are likely to impact stream chemistry patterns and processes. To investigate drying and wildfire effects on stream chemistry (carbon, nutrients, anions, cations, and isotopes), we examined seasonal drying in two intermittent streams in southwestern Idaho, one stream that was unburned and one that burned 8 months prior to our study period. During the seasonal recession following snowmelt, we hypothesized that spatiotemporal patterns of stream chemistry would change due to increased evaporation, groundwater dominance, and autochthonous carbon production. With increased nutrients and reduced canopy cover, we expected greater shifts in the burned stream. To capture spatial chemistry patterns, we sampled surface water for a suite of analytes along the length of each stream with a high spatial scope (50-m sampling along ~2,500 m). To capture temporal variation, we sampled each stream in April (higher flow), May, and June (lower flow) in 2016. Seasonal patterns and processes influencing stream chemistry were generally similar in both streams, but some were amplified in the burned stream. Mean dissolved inorganic carbon (DIC) concentrations increased with drying by 22% in the unburned and by 300% in the burned stream. In contrast, mean total nitrogen (TN) concentrations decreased in both streams, with a 16% TN decrease in the unburned stream and a 500% TN decrease (mostly nitrate) in the burned stream. Contrary to expectations, dissolved organic carbon (DOC) concentrations varied more in space than in time. In addition, we found the streams did not become more evaporative relative to the Local Meteoric Water Line (LMWL) and we found weak evidence for evapoconcentration with drying. However, consistent with our expectations, strontium-DIC ratios indicated stream water shifted toward groundwater-dominance, especially in the burned stream. Fluorescence and absorbance measurements showed considerable spatial variation in DOC sourcing each month in both streams, and mean values suggested a temporal shift from allochthonous toward autochthonous carbon sources in the burned stream. Our findings suggest that the effects of fire may magnify some chemistry patterns but not the biophysical controls that we tested with stream drying.

Soil and Stream Water Chemistry During Spring Snowmelt

1992 ◽  
Vol 23 (1) ◽  
pp. 13-26 ◽  
Author(s):  
W. H. Hendershot ◽  
L. Mendes ◽  
H. Lalande ◽  
F. Courchesne ◽  
S. Savoie
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Stream Chemistry ◽  
Stream Water Chemistry ◽  
The Matrix ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Best Fit ◽  
Spring Snowmelt ◽  
Over Time

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

scholarly journals Salinization alters fluxes of bioreactive elements from stream ecosystems across land use

2015 ◽  
Vol 12 (23) ◽  
pp. 7331-7347 ◽  
Author(s):  
S. Duan ◽  
S. S. Kaushal
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Fresh Water ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Urban Land Use ◽  
Stream Ecosystems ◽  
Accelerated Weathering ◽  
Nutrient Mobilization ◽  
Riparian Soils

Abstract. There has been increased salinization of fresh water over decades due to the use of road salt deicers, wastewater discharges, saltwater intrusion, human-accelerated weathering, and groundwater irrigation. Salinization can mobilize bioreactive elements (carbon, nitrogen, phosphorus, sulfur) chemically via ion exchange and/or biologically via influencing of microbial activity. However, the effects of salinization on coupled biogeochemical cycles are still not well understood. We investigated potential impacts of increased salinization on fluxes of bioreactive elements from stream ecosystems (sediments and riparian soils) to overlying stream water and evaluated the implications of percent urban land use on salinization effects. Two-day incubations of sediments and soils with stream and deionized water across three salt levels were conducted at eight routine monitoring stations across a land-use gradient at the Baltimore Ecosystem Study Long-Term Ecological Research (LTER) site in the Chesapeake Bay watershed. Results indicated (1) salinization typically increased sediment releases of labile dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), total dissolved Kjeldahl nitrogen (TKN) (ammonium + ammonia + dissolved organic nitrogen), and sediment transformations of nitrate; (2) salinization generally decreased DOC aromaticity and fluxes of soluble reactive phosphorus from both sediments and soils; (3) the effects of increased salinization on sediment releases of DOC and TKN and DOC quality increased with percentage watershed urbanization. Biogeochemical responses to salinization varied between sediments and riparian soils in releases of DOC and DIC, and nitrate transformations. The differential responses of riparian soils and sediments to increased salinization were likely due to differences in organic matter sources and composition. Our results suggest that short-term increases in salinization can cause releases of significant amounts of labile organic carbon and nitrogen from stream substrates and organic transformations of nitrogen and phosphorus in urban watersheds. Given that salinization of fresh water will increase in the future due to human activities, significant impacts on carbon and nutrient mobilization and water quality should be anticipated.

scholarly journals Altitude and Canopy Cover Effects on Air Temperature in a Mountainous Region of Ionian Islands, Greece

2018 ◽  
Vol 13 (3) ◽  
pp. 292-298
Author(s):  
ATHANASIOS KAMOUTSIS ◽  
KOSTAS CHRONOPOULOS ◽  
ARISTIDIS MATSOUKIS
Keyword(s):  
Air Temperature ◽  
Canopy Cover ◽  
Decisive Role ◽  
Thermal Conditions ◽  
Special Importance ◽  
Mean Values ◽  
Ionian Islands ◽  
Hiking Trails ◽  
Forested Areas ◽  
Of Greece

Topography and canopy play a decisive role on air temperature (T) conditions in forested areas. Air temperature is a crucial factor in decision making process for the development of these areas. To our knowledge, there is no information regarding the effect of topography along with canopy cover (Pc) on thermal conditions of a vulnerable mountainous forested region of Greece, Mount (Mt) Aenos in the island of Cephalonia, Ionian Islands, Greece. Therefore, the purpose of our work is the investigation of the aforementioned parameters, especially the effect of altitude (alt) and Pc on T of Mt Aenos. Mean values for maximum air temperature (Tx) and Pc were estimated for twelve sites at various alts in Mt Aenos during the period May-October of three consecutive years (2011-2013). The analysis of the results showed that Tx was related to alt and Pc. Altitude has a greater effect on T in relation to Pc. When examining same or similar alts, an increase of Pc up to 51% resulted in a significant decrease of Tx (p<0.05) up to 3.6 °C. Our findings could be taken into account in planning the construction of hiking trails for recreational activities in Mt Aenos, and, in general, in mountainous forest areas of special importance.

scholarly journals Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach

2017 ◽  
Author(s):  
Anne Marx ◽  
Marcus Conrad ◽  
Vadym Aizinger ◽  
Alexander Prechtel ◽  
Robert van Geldern ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Temporal Variations ◽  
Headwater Stream ◽  
Integral Approach ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Outgassing Rate ◽  
Carbon Dioxide Co2

Abstract. A large portion of terrestrially-derived carbon outgasses as carbon dioxide (CO2) from streams and rivers to the atmosphere. Particularly, the amount of CO2 outgassing from small headwater streams was indicated as highly uncertain. Conservative estimates suggest that they contribute 36 % (i.e., 0.93 petagrams C yr−1) of total CO2 outgassing from all rivers and streams worldwide. In this study, stream pCO2, dissolved inorganic carbon (DIC) and δ13CDIC data were used to determine CO2 outgassing from an acidic headwater stream in the Uhlirska catchment (Czech Republic). This stream drains a catchment with silicate bedrock. The applied stable isotope model is based on the principle, that the 13C / 12C ratio of its sources and the intensity of CO2 outgassing control the isotope ratio of DIC in stream water. It avoids the use of the gas transfer velocity parameter (k) that is highly variable and mostly difficult to constrain. Model results indicate that CO2 outgassing contributed 80 % to the annual stream inorganic carbon loss in the Uhlirska catchment. This translated to a CO2 outgassing rate from the stream of 5.2 t C yr−1 and to 2.9 g C m−2 yr−1, when normalised to the catchment area. Large temporal variations with maximum values during spring snowmelt and summer emphasise the need for investigations at higher temporal resolution. We improved the model uncertainty by incorporating groundwater data to better constrain the isotope compositions of initial DIC. Due to the large global abundance of acidic, humic-rich headwaters, we underline the importance of this integral approach for global applications.

scholarly journals Ocean carbon inventory under warmer climate conditions – the case of the Last Interglacial

2018 ◽  
Vol 14 (12) ◽  
pp. 1961-1976 ◽  
Author(s):  
Augustin Kessler ◽  
Eirik Vinje Galaasen ◽  
Ulysses Silas Ninnemann ◽  
Jerry Tjiputra
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Climatic Conditions ◽  
Interglacial Period ◽  
Quasi Equilibrium ◽  
Biological Pump ◽  
Last Interglacial ◽  
Climate Conditions ◽  
Ocean Carbon ◽  
Carbon Inventory

Abstract. During the Last Interglacial period (LIG), the transition from 125 to 115 ka provides a case study for assessing the response of the carbon system to different levels of high-latitude warmth. Elucidating the mechanisms responsible for interglacial changes in the ocean carbon inventory provides constraints on natural carbon sources and sinks and their climate sensitivity, which are essential for assessing potential future changes. However, the mechanisms leading to modifications of the ocean's carbon budget during this period remain poorly documented and not well understood. Using a state-of-the-art Earth system model, we analyze the changes in oceanic carbon dynamics by comparing two quasi-equilibrium states: the early, warm Eemian (125 ka) versus the cooler, late Eemian (115 ka). We find considerably reduced ocean dissolved inorganic carbon (DIC; −314.1 PgC) storage in the warm climate state at 125 ka as compared to 115 ka, mainly attributed to changes in the biological pump and ocean DIC disequilibrium components. The biological pump is mainly driven by changes in interior ocean ventilation timescales, but the processes controlling the changes in ocean DIC disequilibrium remain difficult to assess and seem more regionally affected. While the Atlantic bottom-water disequilibrium is affected by the organization of sea-ice-induced southern-sourced water (SSW) and northern-sourced water (NSW), the upper-layer changes remain unexplained. Due to its large size, the Pacific accounts for the largest DIC loss, approximately 57 % of the global decrease. This is largely associated with better ventilation of the interior Pacific water mass. However, the largest simulated DIC differences per unit volume are found in the SSWs of the Atlantic. Our study shows that the deep-water geometry and ventilation in the South Atlantic are altered between the two climate states where warmer climatic conditions cause SSWs to retreat southward and NSWs to extent further south. This process is mainly responsible for the simulated DIC reduction by restricting the extent of DIC-rich SSW, thereby reducing the storage of biological remineralized carbon at depth.

scholarly journals Increase of 14C Activity of Dissolved Inorganic Carbon Along a River Course

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 515-521 ◽  
Author(s):  
Dušan Srdoč ◽  
Ines Krajcar-Bronić ◽  
Nada Horvatinčić ◽  
Bogomil Obelić
Keyword(s):  
Aquatic Plants ◽  
Water Samples ◽  
Organic Material ◽  
Root Respiration ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Exchange Process ◽  
Karst Spring ◽  
Stream Waters

Results of measurements for 3 years (1981–1983) of 14C activity of dissolved inorganic carbon (DIG) in water samples from the Korana River, as well as that of recent tufa and aquatic plants, showed that 14C concentration increases from karst spring to the estuary. A model describing the increase of 14C activity was developed assuming that the increase is due to the exchange of the dissolved CO2 in stream water with atmospheric CO2 and to dissolution of CO2 from the decay of organic material and root respiration. It is possible to distinguish these two contributions by measuring the δ13C values of DIC in water. As expected, our data show that the exchange process between atmospheric CO2 and DIC dominates at rapids and waterfalls, while biologic contribution is much higher in lakes and along the lowland flow of the Korana River. Agreement between the calculated and the measured activities supports the proposed mechanisms of chemical and isotopic exchanges in stream waters.

scholarly journals Effects of Wildfires and Ash Leaching on Stream Chemistry in the Santa Ynez Mountains of Southern California

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2402
Author(s):  
Carl Swindle ◽  
Parker Shankin-Clarke ◽  
Matthew Meyerhof ◽  
Jean Carlson ◽  
John Melack
Keyword(s):  
Southern California ◽  
Stream Water ◽  
Fold Increase ◽  
Stream Chemistry ◽  
N Content ◽  
Fire Scar ◽  
Major Cations ◽  
C And N ◽  
Ash Leaching

Wildfires can change ecosystems by altering solutes in streams. We examined major cations in streams draining a chaparral-dominated watershed in the Santa Ynez Mountains (California, USA) following a wildfire that burned 75 km2 from July 8 to October 5, 2017. We identified changes in solute concentrations, and postulated a relation between these changes and ash leached by rainwater following the wildfire. Collectively, K+ leached from ash samples exceeded that of all other major cations combined. After the wildfire, the concentrations of all major cations increased in stream water sampled near the fire perimeter following the first storm of the season: K+ increased 12-fold, Na+ and Ca2+ increased 1.4-fold, and Mg2+ increased 1.6-fold. Our results suggested that the 12-fold increase in K+ in stream water resulted from K+ leached from ash in the fire scar. Both C and N were measured in the ash samples. The low N content of the ash indicated either high volatilization of N relative to C occurred, or burned material contained less N.

scholarly journals ANME-2d anaerobic methanotrophic archaea differ from other ANME archaea in lipid composition and carbon source

2019 ◽  
Author(s):  
Julia M. Kurth ◽  
Nadine T. Smit ◽  
Stefanie Berger ◽  
Stefan Schouten ◽  
Mike S.M. Jetten ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Freshwater Ecosystems ◽  
Anaerobic Oxidation Of Methane ◽  
Marine Environments ◽  
Sulfate Reducing ◽  
Oxidation Of Methane ◽  
Main Carbon Source

AbstractThe anaerobic oxidation of methane (AOM) is a microbial process present in marine and freshwater environments. AOM is important for reducing the emission of the second most important greenhouse gas methane. In marine environments anaerobic methanotrophic archaea (ANME) are involved in sulfate-reducing AOM. In contrast,Ca. Methanoperedens of the ANME-2d cluster carries out nitrate AOM in freshwater ecosystems. Despite the importance of those organisms for AOM in non-marine environments not much is known about their lipid composition or carbon sources. To close this gap, we analyzed the lipid composition of ANME-2d archaea and found that they mainly synthesize archaeol and hydroxyarchaeol as well as different (hydroxy-) glycerol dialkyl glycerol tetraethers, albeit in much lower amounts. Abundant lipid headgroups were dihexose, monomethyl-phosphatidyl ethanolamine and phosphatidyl hexose. Moreover, a monopentose was detected as a lipid headgroup which is rare among microorganisms. Batch incubations with13C labelled bicarbonate and methane showed that methane is the main carbon source of ANME-2d archaea varying from ANME-1 archaea which primarily assimilate dissolved inorganic carbon (DIC). ANME-2d archaea also assimilate DIC, but to a lower extent than methane. The lipid characterization and analysis of the carbon source ofCa.Methanoperedens facilitates distinction between ANME-2d and other ANMEs.

scholarly journals Linking groundwater travel times to stream chemistry, isotopic composition and catchment characteristics

2020 ◽  
Author(s):  
Elin Jutebring Sterte ◽  
Fredrik Lidman ◽  
Emma Lindborg ◽  
Ylva Sjöberg ◽  
Hjalmar Laudon
Keyword(s):  
Travel Time ◽  
Stream Water ◽  
Base Cations ◽  
Base Cation ◽  
Isotopic Signature ◽  
Stream Chemistry ◽  
Travel Times ◽  
Underlying Assumption ◽  
Tracking Model

Abstract. Understanding travel times of rain and snowmelt inputs transported through the subsurface environment to recipient surface waters is critical in many hydrological and biogeochemical investigations. In this study, a particle tracking model approach in Mike SHE was used to investigating the travel time of stream groundwater input to 14 partly nested, long-term monitored boreal sub-catchments. Based on previous studies in the area, we hypothesized that the main factor controlling groundwater travel times was catchment size. The modeled mean travel time (MTT) in the different sub-catchments ranged between 0.5 years and 3.6 years. Estimated MTTs were tested against the observed long-term winter isotopic signature (δ2H, δ18O) and chemistry (base cation concentration and pH) of the stream water. The underlying assumption was that older water would have an isotopic signature that resembles the long-term average precipitation input, while seasonal variations would be more apparent in catchments with younger water. Similarly, it was assumed that older water would be more affected by weathering, resulting in higher concentrations of base cations and higher pH. 10-year average winter values for stream chemistry were used for each sub-catchment. We found significant correlations between the estimated travel times and average water isotope signature (r = 0.80, p 

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