Hydrogen and oxygen isotope composition of precipitation and stream water on sub-Antarctic Marion Island

• Published in: Antarctic Science
• Main Authors: Stowe, M-J., Harris, Chris, Hedding, David, Eckardt, Frank, Nel, Werner
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2017
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Southern Ocean; Indian; Antarc*; Antarctic Science; Marion Island
• Online Access: http://dx.doi.org/10.1017/s0954102017000475; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102017000475

Abstract We measured the hydrogen and oxygen isotope composition (δ 2 H and δ 18 O) of precipitation and stream water from the Soft Plume River at multiple spatiotemporal scales on sub-Antarctic Marion Island, Indian sector of the Southern Ocean. Monthly precipitation δ 2 H and δ 18 O values ranged from -43.7‰ to -14.7‰ and from -7.0‰ to -3.3‰ ( n =13), respectively. Stream water values ranged from -48.0‰ to -25.4‰ for δ 2 H and from -7.6‰ to -4.0‰ for δ 18 O ( n =92). The monthly precipitation data yielded a local meteoric water line with the equation δ 2 H=8.4δ 18 O+11.4. There was no clear seasonality in isotope composition present in precipitation and stream water. Along the stream, no significant difference was observed between sites. However, δ 2 H and δ 18 O values were lower and more variable at the highest site. This is probably the result of the ‘amount effect’, where more precipitation fell at a higher elevation compared with a downstream site in the catchment. The findings illustrate spatiotemporal patterns in precipitation and stream water isotopes and provide insight into mechanisms affecting their composition on sub-Antarctic Marion Island.