scholarly journals The post-monsoon carbon biogeochemistry of the Hooghly–Sundarbans estuarine system under different levels of anthropogenic impacts

2019 ◽  
Vol 16 (2) ◽  
pp. 289-307 ◽  
Author(s):  
Manab Kumar Dutta ◽  
Sanjeev Kumar ◽  
Rupa Mukherjee ◽  
Prasun Sanyal ◽  
Sandip Kumar Mukhopadhyay
Keyword(s):  
Organic Matter ◽  
Anthropogenic Impacts ◽  
C3 Plants ◽  
Estuarine System ◽  
Phytoplankton Productivity ◽  
Organic C ◽  
Hooghly Estuary ◽  
Post Monsoon ◽  
Different Levels ◽  
The Sundarbans

Abstract. The present study focused on understanding differences in the post-monsoon carbon (C) biogeochemistry of two adjacent estuaries undergoing different levels of anthropogenic stresses by investigating anthropogenically influenced Hooghly estuary and mangrove-dominated estuaries of the Sundarbans in the north-eastern India. The salinity of well-oxygenated estuaries of the Sundarbans (DO: 91 %–104 %) varied over a narrow range (12.74–16.69) relative to the Hooghly estuary (0.04–10.37). A mixing model suggested a combination of processes including freshwater intrusion, carbonate precipitation and carbonate dissolution to be a major factor controlling dissolved inorganic C (DIC) dynamics in the freshwater regime of the Hooghly, whereas phytoplankton productivity and CO2 outgassing dominated in the mixing regime. In the Sundarbans, the removal of DIC (via CO2 outgassing, phytoplankton uptake and export to the adjoining continental shelf region) dominated its addition through mineralization of mangrove-derived organic C. The concentration of dissolved organic C (DOC) in the Hooghly was ∼40 % higher than in the Sundarbans, which was largely due to the cumulative effect of anthropogenic inputs, DOC–POC interconversion and groundwater contribution rather than freshwater-mediated input. The measured δ13CPOC in the Hooghly suggested particulate organic matter contributions from different sources (freshwater runoff, terrestrial C3 plants and anthropogenic discharge), whereas the contribution from C3 plants was dominant at the Sundarbans. The significant departure of δ13CPOC from typical mangrove δ13C in the mangrove-dominated Sundarbans suggested significant particulate organic C (POC) modification due to degradation by respiration. The average pCO2 in the Hooghly was higher by ∼1291 µatm compared to the Sundarbans with surface runoff and organic matter degradation by respiration as dominant factors controlling pCO2 in the Hooghly and Sundarbans, respectively. The entire Hooghly–Sundarbans system acted as a source of CO2 to the regional atmosphere with ∼17 times higher emission from the Hooghly compared to the Sundarbans. Taken together, the cycling of C in estuaries with different levels of anthropogenic influences is evidently different, with significantly higher CO2 emission from the anthropogenically influenced estuary than the mangrove-dominated ones.

scholarly journals The postmonsoon carbon biogeochemistry of estuaries under different levels of anthropogenic impacts

2018 ◽  
Author(s):  
Manab Kumar Dutta ◽  
Sanjeev Kumar ◽  
Rupa Mukherjee ◽  
Prasun Sanyal ◽  
Sandip Mukhopadhyay
Keyword(s):  
Anthropogenic Impacts ◽  
River System ◽  
Phytoplankton Production ◽  
Estuarine System ◽  
Phytoplankton Productivity ◽  
Run Off ◽  
Carbon Biogeochemistry ◽  
Different Levels ◽  
The Sundarbans

Abstract. The different aspects of carbon biogeochemistry were studied during the postmonsoon at the Hooghly-Sundarbans estuarine system, a part of the Ganga-Brahmaputra river system located in the northeastern India. The study focused on understanding the differences in carbon biogeochemistry of estuaries undergoing different levels of anthropogenic stress by investigating anthropogenically influenced Hooghly estuary and mangrove-dominated estuaries of the Sundarbans. The salinity of well oxygenated (%DO: 91–104 %) estuaries of the Sundarbans varied over a narrow range (12.74–16.69) during postmonsoon relative to the Hooghly (0.04–10.37). Phytoplankton productivity and carbonate precipitation and/or dissolution were dominant processes controlling DIC dynamics in different parts of the Hooghly, whereas signal for mangrove derived DIC removal was observed in the Sundarbans. Influence of groundwater on estuarine DIC biogeochemistry was also observed in both the estuaries with relatively higher influence at the Hooghly than Sundarbans. In both estuarine systems, DOC behaved non-conservatively with ~ 40 % higher DOC level in the Hooghly compared to the Sundarbans. No significant evidence of phytoplankton production on DOC level was found in these estuaries, however signal of DOC input through pore-water exchange at the Sundarbans was observed. Relatively lower δ13CPOC at the Hooghly compared to the Sundarbans suggest relatively higher terrestrial influence at the Hooghly with a possibility of in situ biogeochemical modifications of POC at the Sundarbans. The freshwater run-off coupled with in situ aerobic OC mineralization controlled estuarine pCO2 level at the Hooghly, whereas the same was principally exogenous for the Sundarbans. The entire Hooghly-Sundarbans system acted as source of CO2 to the regional atmosphere with ~ 17 times higher emission from the Hooghly compared to Sundarbans. The present study clearly establishes the dominance of anthropogenically influenced estuary over relatively pristine mangrove dominated one in the regional greenhouse gas budget and climate change perspective.

scholarly journals Linking patterns of freshwater discharge and sources of organic matter within the Río de la Plata estuary and adjacent marshes

2017 ◽  
Vol 68 (9) ◽  
pp. 1704 ◽  
Author(s):  
Leandro Bergamino ◽  
Mark Schuerch ◽  
Adriana Tudurí ◽  
Silvina Carretero ◽  
Felipe García-Rodríguez
Keyword(s):  
Organic Matter ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Freshwater Discharge ◽  
C3 Plants ◽  
Estuarine System ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Matter Transport

We investigated carbon isotopic ratios (δ13C) v. carbon to nitrogen (C : N) ratios for surface sediments throughout a large estuarine system (Río de la Plata, RdlP), combined with sediment cores from adjacent marshes to infer main carbon sources. We also evaluated the influence of the El Niño–Southern Oscillation (ENSO) and associated high freshwater-discharge events on the organic-matter transport within the estuary. The isotopic pattern in surface sediments of the RdlP showed the upper reaches to be influenced by riverine particulate matter (δ13C range: –24 to –26‰). Similarly, in the sediment cores from marshes of the upper reaches, δ13C values decreased from –24‰ in ancient sediments to –28‰ in recent sediments, reflecting an increased contribution of organic matter from land, including C3 plants and freshwater phytoplankton, during the past 50 years. However, the lower reaches represent a depositional environment of marine algae (δ13C range: –21 to –23‰), with no influence of detritus from adjacent marshes, indicating minor erosion of the marshes in the lower reaches operating as carbon-sink habitats. Our isotopic analysis showed that the transport and deposition of terrigenous organic matter within the RdlP and adjacent marsh habitat appear to be both temporally and spatially linked to hydrology patterns.

Mobility of copper from sulphate and chelate fertilizers in soils

2004 ◽  
Vol 84 (3) ◽  
pp. 283-290 ◽  
Author(s):  
P. L. Flaten ◽  
R. E. Karamanos ◽  
F. L. Walley
Keyword(s):  
Organic Matter ◽  
Root Zone ◽  
Column Experiment ◽  
Canadian Prairie ◽  
Organic C ◽  
Feeding Sites ◽  
Prairie Soils ◽  
Enhanced Mobility ◽  
Restricted Mobility ◽  
Different Levels

Copper is a nutrient known for its lack of mobility in soils. This phenomenon affects fertilizer product and placement options when attempting to correct Cu deficiencies. A column experiment was designed to directly compare the mobility of Cu sulphate (CuSO4 5H2O) and a chelated Cu fertilizer (CuEDTA) in five soils with different levels of organic matter (2 to 108 g kg-1 organic C) and clay (4.1 to 34.9%). The movement of Cu, supplied as Cu sulphate and CuEDTA, through a 10- cm column of soil was examined during a 10-d period by monitoring the Cu concentration in leachate following daily additions of 2 cm deionized water and subsequently assaying the soil columns, in 1-cm increments, for DTPA-extractable Cu (DTPACu). Copper sulphate was virtually non-mobile in all soils with at least 20 g kg-1 organic C and 10% clay. However, in a soil with 2 g kg-1 organic C and 4% clay, Cu sulphate moved as much as 7 cm. The restricted mobility of Cu sulphate in all but one soil in this study suggests that in most western Canadian Prairie soils, having relatively high levels of organic matter and clay, Cu supplied as Cu sulphate should be regarded as immobile from an agronomic perspective. In contrast, a portion (2 to 46%) of the CuEDTA moved through the entire 10 cm column of all soils within 3 d, i.e., following three daily additions of 2 cm of water. The enhanced mobility of the chelated Cu is of agronomic significance in that it suggests that this Cu source is more likely to move into the root zone without incorporation and provide adequate feeding sites for a crop when placed in or near the seedrow. Key words: Cu mobility, Cu sulphate, Cu chelate, soil texture, organic matter, leachate

Justification of the need to increase the fertility of reclaimed alluvial soils of JSC «Moskovskoe»

2020 ◽  
pp. 44-48
Author(s):  
Andrey ilinsky ◽  
Alexander Nefedov ◽  
Konstantin Evsenkin
Keyword(s):  
Organic Matter ◽  
Agricultural Land ◽  
Crop Yields ◽  
Anthropogenic Impacts ◽  
Fertility Restoration ◽  
Research Work ◽  
Alluvial Soils ◽  
Ecological Stability ◽  
Reclaimed Land ◽  
Adverse Weather

Global climatic changes, technogenic pollution by pollutants, violations of technologies of exploitation of reclaimed land lead to a decrease in fertility and soil degradation of agricultural land. Adverse weather conditions, resulting in a lack of adequate flood water, and economic difficulties in agriculture make it difficult to fill the deficit of organic matter and macronutrients in reclaimed alluvial soils. The monitoring of agrochemical properties of alluvial meadow medium-loamy soil of the stationary site (reclaimed lands of JSC «Moskovskoye» of Ryazan region), located in the floodplain of the Oka river, conducted by the Meshchersky branch of Vniigim, showed the presence and intensification of degradation changes in the soil. Thus, comparing the agrochemical indicators in the layer 0–20 cm, carried out in 1995, with the indicators of 2019, it should be noted a decrease in soil fertility. The decrease in soil quality was expressed in a decrease in the amount of mobile phosphorus by 37.6 %, mobile potassium by 53.3 %. Also, during this time there was a decrease in organic matter by 9.1 %, and an increase in soil acidity was 0.6 pH. As a result of such changes, soils lose ecological stability and become more vulnerable to adverse weather and negative anthropogenic impacts. In such a situation, advanced agricultural techniques should be actively used to obtain guaranteed, environmentally safe crop yields and restore the fertility of degraded reclaimed soils. In this regard, there is a need to develop innovative methods of fertility restoration of degraded alluvial soils in reclaimed lands using multi-component organic-mineral ameliorants. Meshchersky branch performs research work in addressing this issue.

scholarly journals Disturbances to the Ground and to the Stand in Beech Forests Due to Thinning Treatments Performed by Different Levels of Mechanization

2020 ◽  
Vol 3 (1) ◽  
pp. 58
Author(s):  
Rachele Venanzi ◽  
Loredana Barbona ◽  
Francesco Latterini ◽  
Rodolfo Picchio
Keyword(s):  
Soil Moisture ◽  
Forest Soil ◽  
Anthropogenic Impacts ◽  
Tree Canopy ◽  
Forest Operations ◽  
Beech Forests ◽  
High Soil Moisture ◽  
Forest Logging ◽  
Fagus Sylvatica L ◽  
Different Levels

The aim of this work was to assess the possible impacts on the forest soil and stand due to silvicultural treatment and forest operations in a beech high forest. Even aged beech forests (Fagus sylvatica L.) in the Municipality of Cappadocia (L’Aquila) and in the Municipality of Vallepietra (Roma) were analyzed. The analysis of the soil and stand were performed in order to assess the effects attributable to applied silviculture and forest logging. Two different logging methodologies (in particular for the extraction) were applied: mules were used in the areas with greater slopes and with obstacles, while for the areas with better accessibility, mechanical means were used, in this case tractors. In detail, the main objective was to assess the disturbance on the ground and on the stand, generated by the two different levels of mechanization. In addition, it was also interesting to understand the possible effect on the soil and specifically on the partial uncovering where part of the tree canopy was removed. Only through an accurate cross-analysis of the studied parameters and indices could the anthropogenic impacts on the soil and stand due to forest operations be highlighted according to the different logging methodologies applied. The main results showed that the disturbances caused to the soil and stand were essentially caused in the bunching and extraction operations. The importance of avoiding or limiting the continuous passage of vehicles and animals on forest soil clearly emerges, especially in conditions of high soil moisture. It is also important to use correct technologies that are adequate for the specific environmental characteristics and the work plan. Finally, it can be said that there was no difference in the disturbance caused by the two logging methods when compared. Substantial differences in terms of improvement can be defined when comparing the findings of this study with other research studies. This can be done by applying a different type of mechanization with a different logging system.

Microbial and biochemical changes induced by rotation and tillage in a soil under barley production

1993 ◽  
Vol 73 (1) ◽  
pp. 39-50 ◽  
Author(s):  
D. A. Angers ◽  
N. Bissonnette ◽  
A. Légère ◽  
N. Samson
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Matter ◽  
Microbial Biomass ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Soil Layer ◽  
Red Clover ◽  
Organic C ◽  
Top Soil ◽  
Total Organic C

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

Soil stripping and replacement for the rehabilitation of bauxite-mined land at Weipa. I. Initial changes to soil organic matter and related parameters

Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 345 ◽  
Author(s):  
G. D. Schwenke ◽  
D. R. Mulligan ◽  
L. C. Bell
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Field Experiments ◽  
Surface Soil ◽  
Soil Disturbance ◽  
Microbial Biomass C ◽  
Low Grade ◽  
Double Pass ◽  
Organic C ◽  
The Difference

At Weipa, in Queensland, Australia, sown tree and shrub species sometimes fail to establish on bauxite-mined land, possibly because surface-soil organic matter declines during soil stripping and replacement. We devised 2 field experiments to investigate the links between soil rehabilitation operations, organic matter decline, and revegetation failure. Experiment 1 compared two routinely practiced operations, dual-strip (DS) and stockpile soil, with double-pass (DP), an alternative method, and subsoil only, an occasional result of the DS operation. Other treatments included variations in stripping-time, ripping-time, fertiliser rate, and cultivation. Dilution of topsoil with subsoil, low-grade bauxite, and ironstone accounted for the 46% decline of surface-soil (0–10 cm) organic C in DS compared with pre-strip soil. In contrast, organic C in the surface-soil (0–10 cm) of DP plots (25.0 t/ha) closely resembled the pre-strip area (28.6 t/ha). However, profile (0–60 cm) organic C did not differ between DS (91.5 t/ha), DP (107 t/ha), and pre-strip soil (89.9 t/ha). Eighteen months after plots were sown with native vegetation, surface-soil (0–10 cm) organic C had declined by an average of 9% across all plots. In Experiment 2, we measured the potential for post-rehabilitation decline of organic matter in hand-stripped and replaced soil columns that simulated the DS operation. Soils were incubated in situ without organic inputs. After 1 year’s incubation, organic C had declined by up to 26% and microbial biomass C by up to 61%. The difference in organic C decline between vegetated replaced soils (Expt 1) and bare replaced soils (Expt 2) showed that organic inputs affect levels of organic matter more than soil disturbance. Where topsoil was replaced at the top of the profile (DP) and not ploughed, inputs from volunteer native grasses balanced oxidation losses and organic C levels did not decline.

scholarly journals Nutrient behavior in a highly-eutrophicated tropical estuarine system

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Nilva Brandini ◽  
◽  
Ana Paula de Castro Rodrigues ◽  
Ilene Matanó Abreu ◽  
Luiz Carlos Cotovicz Junior ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chlorophyll A ◽  
River Mouth ◽  
Nutrient Concentrations ◽  
Phytoplankton Production ◽  
Small Scale ◽  
Estuarine System ◽  
Temperature Conductivity ◽  
Se Brazil ◽  
Iguaçu River

Abstract Aim: There are few studies dealing with the biogeochemical processes occurring in small estuaries receiving high sewage loading in tropical regions. The aim of this investigation was to characterize the biogeochemical behavior of nutrients in superficial waters collected at the Iguaçu estuarine system, during specific conditions (neap tide), located at the inner sector of a heavily eutrophicated embayment (Guanabara Bay, SE Brazil). Methods Physical and chemical variables were measured in situ (pH, temperature, conductivity, salinity, total dissolved solids, transparency, dissolved oxygen), whereas suspended particulate matter, chlorophyll a, phaepigments and nutrients (carbon, nitrogen and phosphorus forms) were measured in laboratory across the mesohaline estuarine gradient. Results The Iguaçu River mouth is in a high stage of eutrophication, considering nutrient concentrations, chlorophyll a and transparency of water column. Results indicate a transition from heterotrophic conditions to autotrophic conditions, since the nutrients concentrations showed a decreasing pattern along the saline gradient, while the chlorophyll an increased over the transects. The pH values and chlorophyll : phaeopigments ratios are significantly related to the amount and quality of organic matter contents, especially at transects under strong marine influence. More than 95% of the dissolved and total nitrogen concentrations are represented by NH4+ contributions, which are related to the ammonification of organic matter contents in this region, indicating the existence of untreated sewage loads in this area. Conclusion In this study, the Iguaçu River seemed to contribute with high inputs of nutrients that support important phytoplankton production at the inner regions of the bay related to the CO2 sink and autotrophic metabolism, showing the importance of verifying the biogeochemical behaviors of nutrients in estuarine areas, even in small scale.

scholarly journals Nutrient dynamics in the Sundarbans mangrove estuarine system of Bangladesh under different weather and tidal cycles

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Shak Md Bazlur Rahaman ◽  
Lipton Sarder ◽  
Md Sayadur Rahaman ◽  
Alokesh Kumar Ghosh ◽  
Sudhin Kumar Biswas ◽  
...  
Keyword(s):  
Nutrient Dynamics ◽  
Estuarine System ◽  
Tidal Cycles ◽  
Sundarbans Mangrove ◽  
The Sundarbans

scholarly journals Casting Activity ofScherotheca gigasin No-Till Mediterranean Soils: Role in Organic Matter Incorporation and Influence of Aridity

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Paloma Bescansa ◽  
Iñigo Virto ◽  
Oihane Fernández-Ugalde ◽  
María José Imaz ◽  
Alberto Enrique
Keyword(s):  
Organic Matter ◽  
Agricultural Soils ◽  
Nw Spain ◽  
Organic C ◽  
No Till ◽  
Physico Chemical ◽  
C Stocks ◽  
Casting Activity ◽  
Total Organic C

The behaviour of earthworms, their role in organic matter incorporation into the soil, and the influence of aridity in such processes in arid and semiarid regions have scarcely been studied. In this study, physico-chemical analyses of the casts and the surrounding no-till agricultural soils of three experimental sites representing an aridity gradient in Navarre (NW Spain) were done. The casts were formed by the activity of the only anecic species,Scherotheca gigas(Dugès, 1828), ubiquitous in no-till soils in this region. We observed a significant depletion of clay and higher concentration of total organic C and labile C in the form of particulate organic matter (POM) in the casts as compared to the surrounding soil, suggesting selective ingestion of soil byS. gigas. This, together with the observation of increased concentration in POM with increasing aridity, suggests a major role of this species in the observed progressive gains of organic C stocks in no-till soils in the region.

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