Dinitrogen (N-2) fixation rates were measured during early spring across the different provinces of Mediterranean Sea surface waters. N-2 fixation rates, measured using N-15(2) enriched seawater, were lowest in the eastern basin and increased westward with a maximum at the Strait of Gibraltar (0.10 to 2.35 nmol NL-1 d(-1), respectively). These rates were 3-7 fold higher than N-2 fixation rates measured previously in the Mediterranean Sea during summertime and we estimated that methodological differences alone did not account for the seasonal changes we observed. Higher contribution of N-2 fixation to primary production (4-8 %) was measured in the western basin compared to the eastern basin (similar to 2 %). Our data indicates that these differences between basins may be attributed to changes in N-2-fixing planktonic communities and that heterotrophic diazotrophy may play a significant role in the eastern Mediterranean while autotrophic diazotrophy has a more dominant role in the western basin.
Original Publication Citation
Rahav, E., Herut, B., Levi, A., Mulholland, M.R., & Berman-Frank, I. (2013). Springtime contribution of dinitrogen fixation to primary production across the Mediterranean Sea. Ocean Science, 9(3), 489-498. doi: 10.5194/os-9-489-2013
Rahav, E.; Herut, B.; Levi, A.; Mulholland, Margaret; and Berman-Frank, I., "Springtime Contribution of Dinitrogen Fixation to Primary Production Across the Mediterranean Sea" (2013). OEAS Faculty Publications. 29.