Isotope paring technic (IPT) use to measure nitrification, denitrification, anammox and DNRA in estuarine sediments

• Grant number: 22/14875-8
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: March 01, 2023
• End date: July 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Chemical Oceanography
• Principal Investigator: Elisabete de Santis Braga da Graça Saraiva
• Grantee: Paula Carpintero de Moraes
• Supervisor: Marco Bartoli
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Università degli Studi di Parma, Italy
• Associated to the scholarship: 18/24119-0 - Study of the nitrogen cycle in estuarine systems subject to different impacts of natural and anthropic changes on the São Paulo Coast, BP.PD

Abstract

The 15N stable isotope pairing technique (IPT) has been used to determine rates of benthic N loss and retention processes for a long time, but your use for in situ measurements with benthic chambers is still not total determined. We use the 15NO3- addition to laboratorial whole core incubations to observe the nitrogen pathways in two estuarine systems of São Paulo (Brazil) as part of the project entitled "Study of the nitrogen cycle in estuarine systems subject to different impacts of natural and anthropic changes on the São Paulo coast". In this five months internship proposal we aimed to finalize the analyzes collected after the addition of 15NO3- where we applied the modified IPT methodology. The production of 15N-N2 and 15NH4+ during the experimental time will be measured for the calculations of nitrification, denitrification, anammox and DNRA rates. All the samples were collected and will be analyzed at Laboratory of Benthic Functioning of University of Parma. Additionally, an in situ experiment will be carried out in the estuarine region of Sacca di Goro. Here the IPT will be applied to set a methodology for measurements of the benthic nitrogen processes after the addition of 15NO3- in benthic chambers. (AU)