• SUDHA AGRAHARI

Articles written in Journal of Earth System Science

• Implication of submarine groundwater discharge to coastal ecology of the Bay of Bengal

The present study is undertaken in the eastern coast of India, along the coastal tract of Bay of Bengal (BoB), to delineate the submarine groundwater discharge (SGD)-borne nutrient flux at temporal scale and their impact to coastal ecology and biogeochemical processes. Solutes chemistry, seepage meter study, stable-isotopic signature, and geophysical techniques were used to identify the surface water–groundwater interaction zone, SGD rate and nutrient flux. The estimated rate of major annual discharge of nutrient fluxes were 240 and 224 mM $\rm{m^{-2} day^{-1}}$ for $\rm{NO}_{3}^{-}$ and Fetot. The variation of solute and nutrient fluxes was depending on the load of terrestrial water masses, which is triggered by the local monsoonal meteoric recharge. The ecohydrological response to this solute flux results in spatio-temporal patterns of N and P-sensitive algal blooms in the intertidal zones. Most algae were identified as dinoflagellates and some haptophytes, with greenish and brownish hue that provides a distinct look to the coastal landscape. The algal blooms were found to be substantially influenced by the seasonal-nutrients flux and discharge location. Our study is expected to increase the understanding of a rarely reported ecohydrological response to terrestrial–marine water interactions and their implications in the tropical ocean adjoining the Indian Subcontinent.

• Geochemistry of the Heavy Mineral Sands from the Garampeta to the Markandi beach, southern coast of Odisha, India: Implications of high contents of REE and Radioelements attributed to Placer Monazite

This study presents major element, radioactive element and rare earth element (REE) concentrations of the Garampeta to Markandi beach along the southern coast of Odisha, India to delineate the source signature and resource potential of the beach placer deposits. Average $\sum$REE concentration of the beach sand samples is about four times higher than the average crustal concentration. The LREE concentration is higher than HREE, with a pronounced negative europium anomaly. The study also discusses about the radioelement $^{238}$U, $^{232}$Th and $^{40}$K concentrations in the study area, and their relationship with REE. Weathering condition of the source rock, based on the major elements and Th$/$U ratio indicated a reasonably high degree of weathering. Major element and the REE composition along with the europium anomaly, relate the beach placers to mainly charnockite and khondalite source. An elevated level of thorium (>60 times than the average UCC values) as exhibited by the samples could be attributed due to the presence of monazites. The high concentration of REEs like Nd and Dy along with La and Ce indicates significant REE resource potential in the beach placers which is important for the resource potential in terms of the strategic mineral reserves of the country.

• # Journal of Earth System Science

Volume 129, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019

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