Ph.D. Scholar  ·  IISER Kolkata  ·  Geological Sciences

ManojJakhar

Hydrogeologist & isotope geochemist — tracing water sources, nitrate contamination, and groundwater–surface water interactions across India's most demanding landscapes.

5+
Field Sites
3
Active Projects
2
Conferences
AIR 19
CSIR–NET JRF
Get in Touch View Research Publications
Manoj Jakhar

Manoj Jakhar
Ph.D. Scholar, Dept. of Earth Sciences
IISER Kolkata, West Bengal, India

About

Decoding Earth's
Water Story

I am a Ph.D. scholar at IISER Kolkata working at the intersection of isotope geochemistry and hydrology. My research spans hypersaline Ramsar wetlands, high-altitude cold deserts, and the sprawling Gangetic floodplain.

I use stable isotopes (δ¹⁸O, δ²H, δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻) and radon-222 as environmental tracers, alongside QGIS, ERA-5, and GRACE data to understand how water moves, mixes, and becomes contaminated.

I led the first operational setup of the RAD-8 system for ²²²Rn analysis in our lab — and believe good science begins with boots-on-the-ground fieldwork.

Water source tracing using δ¹⁸O & δ²H isotopes
Dual-isotope nitrate fingerprinting (δ¹⁵N-NO₃⁻ & δ¹⁸O-NO₃⁻)
Groundwater–surface water interaction using ²²²Rn tracer
GRACE & ERA-5 for regional groundwater change assessment
Technical Toolkit

Skills &
Instruments

Instruments

Gas Bench IRMSDual Trap IRMS RAD-8 (Rn-222)LTQ XL HPLC-MS GC-MSStereo Microscope

Software

QGISMATLAB PythonLaTeX Remote SensingGRACE

Field Methods

pH / EC / DO / TDSRadon in-situ Sample collectionBedload sampling

Analysis

Catchment delineationSpatial interpolation ERA-5 temporal analysis
Academic Journey

Education & Training

Dec 2023 – Present
Ph.D. in Geological Sciences
Indian Institute of Science Education and Research (IISER), Kolkata
Tracing water sources, nitrate contamination, and groundwater–surface water interactions using stable isotopes and radon as environmental tracers. Led the first operational setup of the RAD-8 system for ²²²Rn analysis at IISER Kolkata — tested across freshwater & hypersaline wetlands, groundwater, surface water, and riverine systems.
July 2017 – June 2022
B.S. – M.S. in Geological Sciences
IISER Kolkata  ·  SGPA: 7.97
Thesis: Understanding Paleo-fires from the Quaternary Sediments of the Ganga Basin using a Multiproxy Approach. Used GC-MS for PAH identification and stereo-microscopy for charcoal identification.
30 June – 4 July 2025  ·  Roorkee
Advanced Course: Environmental Tracers in Water Resources
National Institute of Hydrology (NIH) + British Geological Survey (BGS)  ·  Sponsored
Advanced sampling, isotope measurement techniques, and tracer-based analytical methods applied to hydrological processes.
7–9 March 2024  ·  Ahmedabad
Short Course: Isotopes in Nature
Physical Research Laboratory (PRL)  ·  Travel Grant Awardee
Isotope fundamentals, dating methods, mass spectrometry, isotope geology. Application of stable and cosmogenic isotopes to natural processes and Earth system data.
Active Research

Projects & Field Work

🌊
MoE-STARS
Isotopic & Microbial Approach – Lower Ganga Plain & Estuary
Elucidating anthropogenic influence on hydrology and nutrient cycles using isotopic fingerprinting along the lower Ganga corridor.
🌾
BRNS / DST
Sustainable Agri-Water Use in the Hindon Sub-Basin
Multi-scale participatory approach to co-create sustainable agricultural water management. Dual-isotope nitrate measurements of water samples.
🏔️
IAEA
Wetland Groundwater Ecosystem Interactions
Isotopic assessment of climatic and hydrological change impacts — covering hypersaline Ramsar wetland (Thar), freshwater wetlands (Ganga), and high-altitude Ladakh.
Field Expeditions
🏜️
Rajasthan, India
Thar Desert – Hypersaline Ramsar Wetland
Designed and conducted sampling at a hypersaline Ramsar wetland. Collected water, bedload, and vegetation samples; recorded in-situ parameters.
🏔️
Indus River Corridor
Ladakh – High-Altitude Cold Desert
Planned and led field sampling in the high-altitude cold desert along the Indus River for stable isotope and radon analysis.
🌿
West Bengal, India
Lower Gangetic Floodplain
Led multiple freshwater wetland expeditions. Coordinated tributary sampling for the lower Ganga with the lab team.
Peer-Reviewed Work

Publications & Conferences

'25
EGU General Assembly 2025
Water isotopes and ²²²Rn in disentangling the impact of macro-scale climatic controls and micro-scale hydrological processes in groundwater-wetland ecosystems in the lower Gangetic plain, Indian Peninsula
Sanyal, P.; Kumar, V.; Jakhar, M.
'25
AGU Annual Meeting 2025 Abstract Accepted
Deciphering Groundwater Nitrate Origins in a Hypersaline Inland Wetland through Isotopic Fingerprinting
Jakhar, M.; Sanyal, P.
Where I've Worked

Field Sites Map

Recognition

Awards & Achievements

🏆
CSIR–NET JRF
All India Rank — 19
National Eligibility Test 2023. Awarded Junior Research Fellowship to pursue Ph.D. in India. Conducted by CSIR.
📐
GATE 2023
Graduate Aptitude Test in Engineering
National-level postgraduate entrance examination conducted by IITs.
✈️
PRL Travel Grant
Physical Research Laboratory, 2024
Awarded travel grant to attend the Short Course on "Isotopes in Nature" at PRL Ahmedabad.
Research Notes

Blog & Field Diaries

🌊
Isotope Hydrgeologist
What Oxygen Isotopes Tell Us About Your Drinking Water
A plain-language explainer on how δ¹⁸O and δ²H ratios fingerprint the origin of any water sample.
5 min readDraft
🏔️
Field Notes
Sampling at 11,000 ft: Lessons from Ladakh
The logistics, the cold, and the surprising hydrogeochemistry of high-altitude glacial meltwater mixing with deep groundwater.
8 min readDraft
🌾
Environmental Science
Nitrate in Groundwater: Agriculture's Invisible Footprint
How intensive farming in the Indo-Gangetic Plain reshapes the nitrogen cycle — and what dual-isotope tracing reveals.
6 min readDraft
Say Hello

Get in Touch

📍
Address
E-043, Research Complex,
IISER Kolkata, Mohanpur,
West Bengal – 741246, India
🎓
Department
Department of Earth Sciences
Ph.D. Scholar (Dec 2023 – Present)
🔬
Research Area
Isotope Hydrology &
Environmental Tracers
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