India Progresses on Research of Ice Core and Lakes in Antarctica

By Kalpana Palkhiwala
Deputy Director (M & C), Press Information Bureau, New Delhi.

New Delhi, July 7, 2011 (Washington Bangla Radio / PIB India) The Antarctic Continent is the coldest region on the earth. Most of  the land here is buried underneath masses of ice and snow. Indian scientists are studying the ice core to unravel history of geographical features of the continent and to learn various aspects of climate change due to environmental variations, volcanic activity, signs of life etc. Two main studies being done are Ice Core Study and Lake’s Study.

Scientist Team from India in Antarctica Ice Core and Lake Research

Ice Core Studies

Locked up in its ice sheet at Antarctic is a record of the history of life and environment for the last several hundreds to thousands of years. Ice cores recovered from polar ice sheets in general offers the best possibility of reconstructing the past atmospheric composition. Several ice cores have been drilled from the ice sheets covering Greenland and Antarctica over the years. Records of past volcanic eruptions and accumulation rates of ice, climatic and environmental changes, atmospheric and nuclear fallout, and solar and terrestrial variability for several thousands of years have been derived from ice cores. Considering potential of ice core for environmental and the lack of data from the DML, India has made its foray into Antarctic ice core research by carrying out shallow drilling.

Ice Core Laboratory

The Ice Core Laboratory set up at National Centre for Antarctic and Oceanography Research (NCAOR) for the exclusive archival, processing and analysis of ice cores, is the first of its kind in the whole country and was dedicated to the Nation in January 2005. The major facilities established at the Ice Core Laboratory include: Archival facilities, Processing facilities and Analytical facilities. The Archival facility consists of two large freezer rooms with temperatures of -20˚C for scientific archival of ice cores obtained from Antarctica. In these rooms, high grade Stainless Steel storage racks have been fabricated for properly stacking ice core storage cases. Ice cores are stored in custom-made highly insulative storage cases made of Expanded Poly Propylene (EPP) to protect the ice cores from transient fluctuations in temperature. The Processing facility has been setup in -15˚C room fitted with specialized pinewood and SS work tables. For sub-sampling and slicing the ice cores for various analytical measurements, custom-made precision band-saw-machines have been fitted on top of the work tables. In order to remove the contaminants from the ice core surface, microtome blades are used  to remove the outer layers. Further processing and clean chemistry analyses are done in a dedicated Class 100 Clean room facility.

Some of the analytical instrumentation facilities available at the Ice Core Laboratory include are -  A Quadrupole Inductively Coupled Plasma Mass Spectrometer (ICP-MS) facility equipped with an XII Series Thermo ICP-MS with collision cell technology (CCT) facility for high-sensitivity, ultra-trace elemental studies; Ion Chromatograph facility equipped with a modular, reagent-free Ion Chromatograph integrated with electrochemical suppressors for analyzing trace level impurities of major ions in the ice cores; Stable Isotope Ratio Mass Spectrometer (IRMS) facility equipped with a GV Isoprime system for high sensitivity analysis of the stable isotopes in dual inlet and continuous mode. In addition to the above, the laboratory also has various analytical facilities like Electrical Conductivity Measurement (ECM) facility, ultra-pure water purification system, acid purification system, to name a few.

Under a collaborative project  between  NCAOR and Geological Survey of India (GSI), drilling program in Antarctica has progressed well. Cores of 65 m, 75m and 55 m have been retrieved from the continental ice and ice shelf respectively. Additionally, in order to obtain information on the modern environmental signatures in the Antarctic snow, large number of surface snow samples are collected and studied. The major ion analysis of the ice core from DML region in Antarctica has revealed the existence of several volcanic events. Few are known such as Krakatau (1883), Tambora (1815), and Huaynaputina (1600) eruptions but the eruption of (1809) is unknown. Agung (1963) and Krakatau (1883) eruptions have harboured microbial cells, which suggests that volcanic ash particles could provide a significant micro-niche for microbes and nanobes in the accreted ice.

High-resolution (sampling resolution: ~9 samples in year) studies on the stable isotopes of Oxygen and Hydrogen from an ice core (IND-25/B5) recovered from the DML were used to understand environmental variations in this region. Results from the study have been published in national and international journals and presented at various conferences.

Antarctic Lake Studies

The chilling temperature, lack of sunlight, little rainfall, inferior soil quality and lack of moisture account for scanty flora and fauna in lakes of Antarctica. But fur seals, blue whales, orcas and penguins are found on the periphery of the so called land mass near sea shore. The lakes thus do not have rich flora and fauna, but their study helps to unravel marine influence at some point of time.

Antarctic continent along with its surrounding ocean influences  the  climate  not  just in   the high latitudes but across the entire planet. The Polar Regions are the first to be affected by changes in climate, both in terms of rapidity and intensity. Among the various proxies that archive the information on palaeoclimate, the Antarctic lake sediments play a pivotal role in palaeoclimate investigations. The sediment cores retrieved from the lakes have been used for sedimentological, mineralogical, geochemical and biological studies to decipher the climatic changes that have occurred in the immediate past in Antarctica at different timescale.

A preliminary bathymetric map, estimation of the distribution, thickness and stratigraphy of the sediments underlying the lake etc., were obtained to aid in locating the suitable coring sites and conducting the overall basin analysis. Acoustic techniques such as echo sounding for the depth variation in Priyadarshini Lake have revealed a maximum depth of 5.9m in the north-eastern part of surveyed area of lake. Lake sediment studies on the samples collected from marginal Antarctic lake in the Vestfold Hills of eastern Antarctic region have shown that both agglutinated and calcareous types of foraminifera tests are present in the 24 cm long sediment core. The presence of the foraminifera and grain size variation in low shelf water body clearly reflect marine influence in the form of periodic marine incursions that must have acted to change faunal composition in the past. As a part of multidisciplinary collaborative work on palaeoclimate, five sediment cores have been subjected to various investigations.

Core logging, grain size analyses, mineral magnetic observations, geochemistry, sedimentological and AMS dates (~32,655 years BP) of the cores have yielded significant results. Multiproxy biological data (pollen, diatom, other alga) generated from sediments has been used for paleoclimatic reconstruction over polar region.

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