Iron (Fe) is the fourth most abundant metal of the Earth's crust and the study of its biogeochemical cycle is crucial to understand how the biological carbon pump might evolve under a global warming scenario. It is a coenzyme in several biological processes such as atmospheric nitrogen fixation and photosynthesis. Its presence may limit primary productivity in the so-called High-Nutrient Low-Chlorophyll (HNLC) regions, which are characterized by a high concentration of nutrients (e.g. nitrate and phosphate) but a low marine productivity. Thus, understanding the processes that can influence Fe solubility and bioavailability is fundamental to evaluate how the Fe supply can influence the productivity in those areas. Even though Svalbard Islands are not a Fe-limited ecosystem, they represent a perfect location where it is possible to perform studies on the Fe biogeochemistry. In Spring 2017, a pioneering study was performed to understand which elements can influence Fe solubility in ice and snow matrices. Thanks to the Iron Speciation in Svalbard Ice Core and Snow (ISSICOS) project, a 10-meters long ice core was taken and analyzed to evaluate the Fe2+ concentration. Linking its concentration with other organic and inorganic compounds, it was observed that organic ligands (acetate, formiate and glycolate) were significant correlated with Fe2+, suggesting that they can play a role in keeping it in its soluble form. Unfortunately, due to summer snow melting that has affected the sampling site, it was impossible to state whether the organic ligands were produced by in situ bacteria or they were transported by the wind. Nevertheless, our study, with the validation of a new analytical method, represents a starting point to evaluate which processes may intervene in influencing Fe speciation and solubility in ice and snow matrices.
Iron speciation on Svalabard ice cores. First results and future perspectives
E Barbaro;C Turetta;G Dreossi;C Barbante;A Spolaor
2019
Abstract
Iron (Fe) is the fourth most abundant metal of the Earth's crust and the study of its biogeochemical cycle is crucial to understand how the biological carbon pump might evolve under a global warming scenario. It is a coenzyme in several biological processes such as atmospheric nitrogen fixation and photosynthesis. Its presence may limit primary productivity in the so-called High-Nutrient Low-Chlorophyll (HNLC) regions, which are characterized by a high concentration of nutrients (e.g. nitrate and phosphate) but a low marine productivity. Thus, understanding the processes that can influence Fe solubility and bioavailability is fundamental to evaluate how the Fe supply can influence the productivity in those areas. Even though Svalbard Islands are not a Fe-limited ecosystem, they represent a perfect location where it is possible to perform studies on the Fe biogeochemistry. In Spring 2017, a pioneering study was performed to understand which elements can influence Fe solubility in ice and snow matrices. Thanks to the Iron Speciation in Svalbard Ice Core and Snow (ISSICOS) project, a 10-meters long ice core was taken and analyzed to evaluate the Fe2+ concentration. Linking its concentration with other organic and inorganic compounds, it was observed that organic ligands (acetate, formiate and glycolate) were significant correlated with Fe2+, suggesting that they can play a role in keeping it in its soluble form. Unfortunately, due to summer snow melting that has affected the sampling site, it was impossible to state whether the organic ligands were produced by in situ bacteria or they were transported by the wind. Nevertheless, our study, with the validation of a new analytical method, represents a starting point to evaluate which processes may intervene in influencing Fe speciation and solubility in ice and snow matrices.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
