Analytical Hierarchy Process Tool in Google Earth Engine platform : A case study of a tropical landfill site suitability

Kolkata being a metropolitan city in India, has its main Municipal Solid Waste dumpsite situated at Dhapa just adjacent to the East Kolkata Wetlands Ramsar site. The current prevalent situation at Dhapa is open dumping leading to various contaminations and hazards putting forth the need to look for alternative sites where the landfiilling operation can be shifted to using scientific methods. A User Interface (UI) based Analytical hierarchy process (AHP) tool has been developed within the Google Earth Engine (GEE) cloud platform to find out the alternative dumping sites using geospatial layers. AHP function is not available as a native algorithm or developed by any researcher in GEE. The tool has three major functionalities, of which the first one handles the UI elements. The AHP procedure is within another function, and the last function integrates the AHP coefficients to the layers generating the final suitability layer. Users can also upload comparison matrix as GEE asset in the form CSV file which gets automatically integrated into the AHP to calculate the coefficients and consistency ratio to generate the spatial suitability layers. This approach showcases a generalized AHP function within the GEE environment, which has been done for the first time. The tool is designed in the cloud platform which is dynamic, robust and suitable for use in various AHP-based suitability analysis in environmental monitoring and assessment.

Influence of Aquatic pH on Dissolved Pb in East Kolkata Wetlands: A Case Study With Reference to Climate Change Induced Acidification

The present study was undertaken with the databank of dissolved Pb and pH of the aquatic system in the East Kolkata Wetlands, an internationally unique Ramsar Site of Eastern India during a period of twenty years (2000-2019). Our study site is receiving huge amounts of domestic and industrial wastewater from surrounding areas of highly populated metropolitan city of Kolkata. The data on pH exhibits a decreasing trend with the passage of time, which may be attributed to the phenomenon of acidification in which CO2 dissolves with the water and shifts the pH to a lower value. This may result in the dissolution of accumulated Pb in the sediment and transfer the same to the overlying aquatic phase. The increasing trend of dissolved Pb confirms the hypothesis. The significant negative correlation between pH and dissolved Pb (r= -0.7763; p≤0.01) supports the view of the regulatory effect of pH on the dissolved Pb level in the aquatic systems of East Kolkata Wetland.

Seasonal Variation of Culturable Benthic Soil Prokaryotic Microbiota as Potential Fish Pathogens and Probiotics from an Aquaculture Farm in East Kolkata Wetlands, India

Rising demand in the aquaculture sector tends towards finding innovative ways to promote better yield and profitability. Benthic soil microbiota can provide an insight into the potent opportunistic fish pathogens as well as probiotics present in the aquaculture system. This study reports the seasonal diversity and abundance of fifteen culturable pathogenic bacterial strains belonging to the genera of Comamonas, Aeromonas, Providencia, Klebsiella, Escherichia, Acinetobacter, Serratia, Stenotrophomonas, Staphylococcus, and Enterobacter along with nine probiotic strains native to genera of Bacillus and Pseudomonas isolated from an aquaculture farm benthic soil, located in East Kolkata Wetlands, West Bengal, India. Strains are isolated using traditional microbial culture methods and tested for their antimicrobial susceptibility against commonly available antibiotics. 16S rDNA analysis was done for the identification of the strains and the establishment of their phylogenetic relationships. Among the isolates, B. pumilus strain S8 in the pre-monsoon sample, E. coli strain M2aR1 in the monsoon sample, and A. hydrophila strain P6dF1 in the post-monsoon sample were the most abundant having MPN counts of 275±21 x 106 CFU/gram dry soil, 278±18 x 106 CFU/gram dry soil, and 321±28 x 106 CFU/gram dry soil respectively. Data on the temporal diversity, abundance, and drug-susceptibility of prokaryotic fish-pathogens and probiotics can be used to formulate measures for sustainable aquaculture practices with reduced maintenance costs.