April 9, 2024 Gherardi, L. A. and O. E. Sala. 2019. Global patterns and climatic controls of belowground net carbon fixation. Proceedings of the National Academy of Sciences of the United States of America 117(33):20038-20043. Home » Gherardi, L. A. and O. E. Sala. 2019. Global patterns and climatic controls of belowground net carbon fixation. Proceedings of the National Academy of Sciences of the United States of America 117(33):20038-20043.