YOU ARE WHAT YOU EAT: STABLE ISOTOPE SIGNATURE OF THE SEAGRASS POSIDONIA OCEANICA IN PANAREA HYDROTHERMAL VENTS

Federica Relitti; Nives Ogrinc; Valentina Esposito; Maria Cristina Gambi; Doris Potočnik; Michele Giani; Cinzia De Vittor

Federica Relitti National Institute of Oceanography and Applied Geophysics — OGS, Trieste (Italy)
Nives Ogrinc Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana (Slovenia)
Valentina Esposito National Institute of Oceanography and Applied Geophysics — OGS, Trieste (Italy)
Maria Cristina Gambi National Institute of Oceanography and Applied Geophysics — OGS, Trieste (Italy)
Doris Potočnik Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana (Slovenia)
Michele Giani National Institute of Oceanography and Applied Geophysics — OGS, Trieste (Italy)
Cinzia De Vittor National Institute of Oceanography and Applied Geophysics — OGS, Trieste (Italy)

Keywords: CO2 emissions, δ13C, δ15N, δ34S, Aeolian Archipelago

Abstract

The hydrothermal area of Panarea (Aeolian Islands) represents a valuable natural laboratory to study the effects of ocean acidification (OA) on Posidonia oceanica (L.) Delile, that populate these shallow vents expressing unique plant features. Stable isotopes of carbon, nitrogen and sulphur (δ¹³C, δ¹⁵N, δ³⁴S), powerful indicators of the origin and dynamics of these elements widely applied to P. oceanica, were measured in leaves collected in May 2017 and September 2018 in three vent systems and two control areas off Panarea. δ¹³C results show that strong hydrothermalism is still active in the area, and that P. oceanica can record changes occurring in the surrounding environment. The coupling with δ¹⁵N provides useful information about the physiology of the plant under OA. The preliminary δ³⁴S results encourage further investigation of this element cycle, to understand the dynamics and origin of sulphur in the hydrothermal areas.