Vertical distribution of forms of potassium in major soil series of Tamil Nadu

2003 ◽  
Vol 51 (3) ◽  
pp. 339-346 ◽  
Author(s):  
S. Natarajan ◽  
A. Renukadevi

Fifteen major soil series at the rate of three for each soil group, namely red non-calcareous, red calcareous, black calcareous, brown calcareous and alluvial soils, were studied for the vertical distribution of different forms of potassium. The total potassium content varied from 515-5513 ppm and generally increased with depth. It was positively related with clay, silt, CaCO3, CEC and total Ca. Non-exchangeable K ranged from 340-1326 ppm and did not exhibit any uniformity in its distribution in soil profiles. The exchangeable K varied from 45-684 ppm and was positively related to organic carbon. NH4OAc-K ranged from 15-298 ppm. Soil properties like clay, silt, CaCO3 and organic matter were positively related to available K. Water-soluble K varied from 2-33 ppm and was found to decrease with the depth of the soil profile. It was positively correlated with organic carbon and negatively related to clay plus silt. Studies on the relationship between the above forms of potassium indicate that, except for total K, the other forms were closely related, indicating the possibility of predicting one from the other.

2020 ◽  
Vol 9 (2) ◽  
pp. 125-132
Author(s):  
Triyanti Nurhidayah ◽  
Lilik Maslukah ◽  
Sri Yulina Wulandari ◽  
Kurnia Kurnia

Pantai Marunda terletak di Teluk Jakarta dan berdekatan dengan muara Sungai Tiram. Kegiatan antropogenik di sekitar Pantai Marunda sangat tinggi, sehingga dapat menyumbang limbah yang mengandung logam berat Pb, Zn dan Cr. Limbah logam berat yang terakumulasi dalam perairan, akan  mengendap dalam sedimen dan seiring berjalannya waktu akan mengalami peningkatan. Tujuan dari penelitian ini, untuk mengetahui konsentrasi Pb, Zn, dan Cr berdasarkan kedalaman vertikal, hubungannya dengan karbon organik total (KOT) dan ukuran butir sedimen di Pantai Marunda. Sampel sedimen diambil menggunakan polietylen sediment core dan dipisahkan berdasarkan kedalamannya (1-3 cm, 4-6 cm, dan 7-9 cm). Logam berat dalam sedimen dianalisis menggunakan metode destruksi asam dan diukur nilai absorbansinya menggunakan AAS, karbon organik total menggunakan metode loss of ignition (LOI) dan analisa tekstur sedimen dengan metode pengayakan dilanjutkan pemipetan. Hasil menunjukkan bahwa konsentrasi rerata logam berat Pb, Zn, Cr secara berurutan pada lapisan atas sebesar 5,14; 107,19; dan 12,79 ppm, lapisan tengah sebesar 4,41; 100,20; 12,28  ppm serta lapisan bawah sebesar 4,8; 101,30; 14,10 ppm. Logam berat Zn dan Cr berkorelasi positif kuat terhadap KOT dan persentase lumpur, sedangkan terhadap Pb berkorelasi negatif. Hasil penelitian ini menggambarkan bahwa distribusi logam berat Pb, Zn dan Cr secara vertikal menunjukkan konsentrasi tinggi pada lapisan permukaan yaitu pada kedalaman sedimen 1-3 cm dan keberadaanya ditentukan oleh konsesntrasi  KOT dan fraksi sedimen jenis lumpur. The Marunda Beach is located on the Jakarta Bay and adjacent to the mouth of the Tiram River. Anthropogenic activity around Marunda Beach is very high, so it can contribute the heavy metals such as Pb, Zn and Cr. The heavy metal will accumulate in the sediment and over time will be increase. The purpose of this study was to determine the vertical distribution of Pb, Zn, Cr, and their relationship to total organic carbon (TOC) and the grain size. Sediment samples were taken using polyethylene cores and this sample separated based on their depth (1-3 cm, 4-6 cm, and 7-9 cm). The heavy metals were analyzed using acid destruction and absorbance values were measured using AAS, TOC using the loss of ignition (LOI) and sediment texture with a sifting method, followed by pipetting. The results showed that the average concentration of Pb, Zn, Cr in the upper layer was 5.14; 107.19; 12.79 ppm, in the middle layer of 4.41; 100.20; 12.28 ppm and in the lower layer 4.8; 101.30; 14.10 ppm, respectively. Zn and Cr are strongly positively correlated to TOC and mud, and vice versa, the relationship to Pb is negative. The results of this study found that the vertical distribution of Pb, Zn and Cr was high in the surface layer (1-3 cm) and their presence was determined by TOC concentration and mud fraction.


MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 275-278
Author(s):  
A.L. KOPPAR ◽  
S.C. NAGRATH

Ozone soundings made from Dakshin Gangotri, Antarctica during 1987 are presented. The vertical distribution of ozone over Antarctica is characterised by a double peak profile, one around 200-150 hPa and the other around 50 hPa. During late winter-early spring the upper peak is considerably depleted. Tropospheric ozoe remains low and nearly constant throughout the year.  


Author(s):  
R. Sauzède ◽  
J. E. Johnson ◽  
H. Claustre ◽  
G. Camps-Valls ◽  
A. B. Ruescas

Abstract. Understanding and quantifying ocean carbon sinks of the planet is of paramount relevance in the current scenario of global change. Particulate organic carbon (POC) is a key biogeochemical parameter that helps us characterize export processes of the ocean. Ocean color observations enable the estimation of bio-optical proxies of POC (i.e. particulate backscattering coefficient, bbp) in the surface layer of the ocean quasi-synoptically. In parallel, the Argo program distributes vertical profiles of the physical properties with a global coverage and a high spatio-temporal resolution. Merging satellite ocean color and Argo data using a neural networkbased method has already shown strong potential to infer the vertical distribution of bio-optical properties at global scale with high space-time resolution. This method is trained and validated using a database of concurrent vertical profiles of temperature, salinity, and bio-optical properties, i.e. bbp, collected by Biogeochemical-Argo (BGC-Argo) floats, matched up with satellite ocean color products. The present study aims at improving this method by 1) using a larger dataset from BGC-Argo network since 2016 for training, 2) using additional inputs such as altimetry data, which provide significant information on mesoscale processes impacting the vertical distribution of bbp, 3) improving the vertical resolution of estimation, and 4) examining the potential of alternative machine learning-based techniques. As a first attempt with the new data, we used some feature-specific preprocessing routines followed by a Multi-Output Random Forest algorithm on two regions with different ocean dynamics: North Atlantic and Subtropical Gyres. The statistics and the bbp profiles obtained from the validation floats show promising results and suggest this direction is worth investigating even further at global scale.


2017 ◽  
Vol 107 (0) ◽  
Author(s):  
Kcrishna V. S. Barros ◽  
Jesser F. Souza-Filho ◽  
Ricardo J. C. Paiva ◽  
Catarina L. Araújo-Silva ◽  
Alexandre O. Almeida ◽  
...  

ABSTRACT The different microhabitats provided by seagrasses and the habit of the species determinate the vertical distribution of crustaceans. This study verified the influence of the seasonality on the spatial distribution of the crustacean community associated with a Halodule wrightii meadow. From April 2006 to July 2007, we performed fifteen samplings in Goiabeiras Beach, Ceará State, each with five sectioned replicates in belowground and aboveground. Cumaceans and the amphipod Hyale media (Dana, 1853) had a higher frequency, density, and dominance than the other taxa, in both strata. The community exhibited gradual changes along the study, in both the belowground and aboveground strata, but the seagrass structure was not sufficient to explain the vertical distribution of the crustacean fauna along the time.


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