scholarly journals Discrimination of topsoil environments in a karst landscape: an outcome of a geochemical mapping campaign

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Ozren Hasan ◽  
Slobodan Miko ◽  
Nikolina Ilijanić ◽  
Dea Brunović ◽  
Željko Dedić ◽  
...  
Keyword(s):  
Discriminant Function ◽  
Karst Area ◽  
Soil Geochemistry ◽  
Dinaric Karst ◽  
Potentially Harmful Elements ◽  
Environmental Criteria ◽  
Karst Soil ◽  
Geologic Setting ◽  
Underlying Mechanisms ◽  
Function Models

AbstractThe study presented in this work emerged as a result of a multiyear regional geochemical survey based on low-density topsoil sampling and the ensuing geochemical atlas of Croatia. This study focuses on the Dinaric part of Croatia to expound the underlying mechanisms controlling the mobilities and variations in distribution of potentially harmful elements as observed from different environmental angles. Although serious environmental degradation of the vulnerable karst soil landscapes was expected to occur chiefly through the accumulation of various heavy metals, the most acute threat materialized through the soil acidification (Al-toxicity) affecting the entire Dinaric karst area. This picture surfaced from the analysis of all three investigated discriminant function models employing the abovementioned environmental criteria selected autonomously with respect to the evaluated soil geochemistry, namely, geologic setting, regional placement and land use. These models are presented by not only the characteristic discriminant-function diagrams but also a set of appropriate mathematically derived geochemical maps disclosing the allocations of potential threats to the karst soil landscapes posed by soil acidity.

scholarly journals Tropical forest soil carbon stocks do not increase despite 15 years of doubled litter inputs

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Emma J. Sayer ◽  
Luis Lopez-Sangil ◽  
John A. Crawford ◽  
Laëtitia M. Bréchet ◽  
Ali J. Birkett ◽  
...  
Keyword(s):  
Organic Matter ◽  
Tropical Forest ◽  
Critical Role ◽  
Tropical Soils ◽  
Soil Geochemistry ◽  
Soil Minerals ◽  
Litter Addition ◽  
Lowland Tropical Forest ◽  
Tropical Forest Soil ◽  
Underlying Mechanisms

AbstractSoil organic carbon (SOC) dynamics represent a persisting uncertainty in our understanding of the global carbon cycle. SOC storage is strongly linked to plant inputs via the formation of soil organic matter, but soil geochemistry also plays a critical role. In tropical soils with rapid SOC turnover, the association of organic matter with soil minerals is particularly important for stabilising SOC but projected increases in tropical forest productivity could trigger feedbacks that stimulate the release of stored SOC. Here, we demonstrate limited additional SOC storage after 13–15 years of experimentally doubled aboveground litter inputs in a lowland tropical forest. We combined biological, physical, and chemical methods to characterise SOC along a gradient of bioavailability. After 13 years of monthly litter addition treatments, most of the additional SOC was readily bioavailable and we observed no increase in mineral-associated SOC. Importantly, SOC with weak association to soil minerals declined in response to long-term litter addition, suggesting that increased plant inputs could modify the formation of organo-mineral complexes in tropical soils. Hence, we demonstrate the limited capacity of tropical soils to sequester additional C inputs and provide insights into potential underlying mechanisms.

scholarly journals Cross-Correlation and Cross-Spectral Analysis of the Hydrographs in the Northern Part of the Dinaric Karst of Croatia

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 86 ◽  
Author(s):  
Krešimir Pavlić ◽  
Jelena Parlov
Keyword(s):  
Spectral Analysis ◽  
Cross Correlation ◽  
Coherence Function ◽  
Karst Area ◽  
Karst Aquifers ◽  
Dinaric Karst ◽  
Input Signals ◽  
Runoff Regime ◽  
Groundwater Reserves ◽  
Insight Into

Correlation and cross-spectral analysis of hydrographs was performed on the karst area of the mountainous section of the Kupa River in two time periods. Since there are karst aquifers in this area that is a part of strategic groundwater reserves of potable water, such an analysis could give better insight into the behavior of these aquifers. The functions used to describe karst aquifers are the cross-correlation function, coherence function, gain function, and phase function. The outcomes of the analysis results were very similar in the two analyzed periods, suggesting that differences in input signals between these two periods do not affect the aquifer function as a system filter. The results of this research suggest that the aquifer and overburden layer characteristics have a much stronger influence than the change of input signal on the runoff regime in the considered period.

DISCRIMINANT FUNCTION MODELS FOR DETERMINATION OF SEX USING ANTHROPOMETRIC FOOT DIMENSIONS IN AN ADULT NIGERIAN POPULATION

2019 ◽  
Vol 7 (4.3) ◽  
pp. 7155-7162
Author(s):  
Ikpa, James Onah ◽  
◽  
Salawu Ahmed Akinjide ◽  
Oshodi Olabode Abdulateef ◽  
Adenuga Omogbolahan Oluyemi ◽  
...  
Keyword(s):  
Discriminant Function ◽  
Nigerian Population ◽  
Function Models

scholarly journals Combined Use of Carbon and Nitrogen Isotopes for Assessment of Soil Organic Matter Sources and Decomposition in a Typical Karst Area of Yunnan–Guizhou Plateau, Southwestern China

2021 ◽  
Author(s):  
Howard Omar Beckford ◽  
Changshun SONG ◽  
Cheng CHANG ◽  
Hongbing JI
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Nitrogen Isotopes ◽  
Karst Area ◽  
Soil Profiles ◽  
Carbon And Nitrogen ◽  
Karst Soil ◽  
Guizhou Plateau

Abstract Soil organic matter (SOM) has substantial influence on geochemical cycle, soil stability and global climate change, however total organic carbon sequestration mechanisms in karst soil remain poorly understood. For this study we assess, total organic content (TOC), total nitrogen (TN), C/N ratio and isotopes of carbon and nitrogen in four soil profiles over critical karst area to investigate organic matter source, mechanisms that influence fractionation and factors affecting SOM in Yunnan–Guizhou Plateau, Southwestern China. The results revealed that SOM comprised of mixed sources derived from both exogenous and endogenous materials. The soil profiles indicate intense vertical variation in δ13C and δ15N with an increase in both isotopes in the upper layers, deceased in δ13C below 20 cm and irregular fluctuation in δ15N with depth. Mechanisms such as mineralization and selective preservation influence isotopic fractionation in the upper soil surface, while translocation, nitrification and denitrification dominated the subsoil layers. Variation in TOC, TN and stable carbon and nitrogen isotopes were influence by vegetation cover, topography, soil water and external contribution. Moreover, the decrease in TOC and TN with depth were due to downward translocation of dissolved organic carbon and nitrogen caused by monsoon climate. Our results revealed that combination of TOC, TN, C/N, δ13C and δ15N can be used as proxy to decipher SOM source, external influence and stability of karst soils. Furthermore, the intense change in δ13C and δ15N throughout the soil profiles suggest that this karst soil is unstable which have implications for land management and carbon sequestration.

scholarly journals Ecological and faunistic features of caddisflies (Insecta: Trichoptera) in different types of habitats in the Dinaric karst area (Central Croatia)

2020 ◽  
Vol 36 ◽  
pp. 6-39
Author(s):  
Darko Cerjanec ◽  
Mladen Kučinić ◽  
Marina Vilenica ◽  
Anđela Ćukušić ◽  
Renata Ćuk ◽  
...  
Keyword(s):  
New Records ◽  
Uv Light ◽  
Light Trap ◽  
Karst Area ◽  
Ecological Knowledge ◽  
Chemical Parameters ◽  
Dinaric Karst ◽  
Ecological Features ◽  
Physico Chemical ◽  
Different Types

Caddisfly faunistic and ecological features were studied at 14 sampling sites along the catchment area of the Dobra River. Adults were collected monthly, over a period of 13 months (from early November 2009 until the end of November 2010), using ultraviolet (UV) light trap and entomological net. Physico-chemical parameters of water and air were also measured at all sampling sites. The study encompassed several segments of caddisfly fauna: the composition, new records, the distribution of all recorded species and seasonal dynamics. A total number of 77 species were recorded, out of which 15 species and four genera were new records for Croatian caddisfly fauna. The CCA analysis showed that the water temperature and the altitude had the highest impact on distribution of caddisfly fauna in this area. The results of this study contribute to the increase of faunistic and ecological knowledge of the Croatian caddisflies.

Use of Otolith Morphology in Stock Discriminations of Atlantic Salmon (Salmo salar)

1994 ◽  
Vol 51 (1) ◽  
pp. 91-98 ◽  
Author(s):  
K. D. Friedland ◽  
D. G. Reddin
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Discriminant Function ◽  
Country Of Origin ◽  
Model Classification ◽  
Atlantic Salmon Salmo Salar ◽  
Shape Indices ◽  
Otolith Morphology ◽  
Input Variables ◽  
Function Models

Shape of sagittal otoliths was used to develop discriminant function models to classify Atlantic salmon (Salmo salar) by continent and country of origin. The outline shape was digitized with an image processor and used to calculate a complex Fourier transform of the closed contour and two shape indices, rectangularly and circularity. The shape indices and the magnitudes of the first 20 nonzero or nonidentity harmonics were used as input variables. Samples were obtained from known-origin one-sea-winter salmon captured in either Canada or West Greenland during 1986–88. Classification by continent of origin was designed to discriminate between North American and European salmon. Jackknifed classification efficiency was 88% for the continent model. Classification by country of origin was designed to discriminate between salmon of United States and Canada origin and between salmon of Ireland and United Kingdom origin; these models performed with classification efficiencies of 64 and 69%, respectively. These results suggest that otolith morphology may be an effective tool to identify continent of origin for salmon fisheries management. However, before the model is implemented, the discriminant function training set should be broadened to include a wider cross section of stocks likely to occur in mixed-stock fisheries.

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