Sethunathasarma Krishnaswami, popularly known as Swami, was an Indian geochemist and an honorary scientist at the geosciences division of the Physical Research Laboratory.
Sethunathasarma Krishnaswami, popularly known as Swami, was an Indian geochemist and an honorary scientist at the geosciences division of the Physical Research Laboratory. He was known for his studies on low temperature geochemistry and was an elected fellow of the Indian Academy of Sciences, Indian National Science Academy, The World Academy of Sciences, National Academy of Sciences, India, American Geophysical Union, Geochemical Society and European Association of Geochemistry (2003). The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Earth, Atmosphere, Ocean and Planetary Sciences in 1984.

S. Krishnaswami did his graduate studies in science at the University College, Thiruvanathapuram of the University of Kerala and on completion of the degree in 1963, he joined Bhabha Atomic Research Centre Training School for a short term training. Subsequently, he joined the Geophysics group of Tata Institute of Fundamental Research as a research associate in 1964 where he stayed till 1972. Simultaneously, he enrolled at Bombay University and secured a PhD in 1974, working under the guidance of Devendra Lal. His post-doctoral research was at Scripps Institution of Oceanography with Harmon Craig and at the laboratory of K. K. Turekian of Yale University. By this time, he had already moved to Physical Research Laboratory (PRL), Ahmedabad in 1973 and on returning to India, he spent the rest of his career there, superannuating from service in 2005. He held various positions during his tenure at PRL such as that of a Dean from 1987 to 1993 and Acting Director during 2004–05 and continued his association with the laboratory post-retirement as an INSA scientist and honorary professor. He also served as a visiting scientist at Scripps Institute of Oceanography (1971–72) and as a visiting faculty at the Department of Geology and Geophysics of Yale University for two stints during 1976–77 and 1986–87.
His researches are known to have established the accretion rate and growth history of ocean-floor ferromanganese nodules which he estimated by radionuclide method and the work assisted in the determination of the history of sedimentation in Indian lakes and coastal regions. He applied these methods in estimating the weathering and erosion in the Himalaya and Deccan traps and for assessing their influence on global change. He was also involved in geochemical studies on the rivers of Ganges and Brahmaputra for assessing the evolution of strontium isotopes and uranium concentration in the ocean since the Cenozoic era