Global Oceanic Diazotroph Database Version 2 and Elevated Estimate of Global N\u3csub\u3e2\u3c/sub\u3e Fixation

Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, the first version of the global oceanic diazotroph database (version 1) was published. Here, we present an updated version of the database (version 2), significantly increasing the number of in situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, diazotrophic cell abundance, and nifH gene copy abundance have increased by 184 %, 86 %, and 809 %, respectively. Version 2 includes two new data sheets for the nifH gene copy abundance of non-cyanobacterial diazotrophs and cell-specific N2 fixation rates. The measurements of N2 fixation rates approximately follow a log-normal distribution in both version 1 and version 2. However, version 2 considerably extends both the left and right tails of the distribution. Consequently, when estimating global oceanic N2 fixation rates using the geometric means of different ocean basins, version 1 and version 2 yield similar rates (43–57 versus 45–63 Tg N yr−1; ranges based on one geometric standard error). In contrast, when using arithmetic means, version 2 suggests a significantly higher rate of 223±30 Tg N yr−1 (mean ± standard error; same hereafter) compared to version 1 (74±7 Tg N yr−1). Specifically, substantial rate increases are estimated for the South Pacific Ocean (88±23 versus 20±2 Tg N yr−1), primarily driven by measurements in the southwestern subtropics, and for the North Atlantic Ocean (40±9 versus 10±2 Tg N yr−1). Moreover, version 2 estimates the N2 fixation rate in the Indian Ocean to be 35±14 Tg N yr−1, which could not be estimated using version 1 due to limited data availability. Furthermore, a comparison of N2 fixation rates obtained through different measurement methods at the same months, locations, and depths reveals that the conventional 15N2 bubble method yields lower rates in 69 % cases compared to the new 15N2 dissolution method. This updated version of the database can facilitate future studies in marine ecology and biogeochemistry. The database is stored at the Figshare repository (https://doi.org/10.6084/m9.figshare.21677687; Shao et al., 2022)

Global oceanic diazotroph database version 2 and elevated estimate of global oceanic N 2 fixation

Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, the first version of the global oceanic diazotroph database (version 1) was published. Here, we present an updated version of the database (version 2), significantly increasing the number of in situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, diazotrophic cell abundance, and nifH gene copy abundance have increased by 184 %, 86 %, and 809 %, respectively. Version 2 includes two new data sheets for the nifH gene copy abundance of non-cyanobacterial diazotrophs and cell-specific N2 fixation rates. The measurements of N2 fixation rates approximately follow a log-normal distribution in both version 1 and version 2. However, version 2 considerably extends both the left and right tails of the distribution. Consequently, when estimating global oceanic N2 fixation rates using the geometric means of different ocean basins, version 1 and version 2 yield similar rates (43–57 versus 45–63 Tg N yr−1; ranges based on one geometric standard error). In contrast, when using arithmetic means, version 2 suggests a significantly higher rate of 223±30 Tg N yr−1 (mean ± standard error; same hereafter) compared to version 1 (74±7 Tg N yr−1). Specifically, substantial rate increases are estimated for the South Pacific Ocean (88±23 versus 20±2 Tg N yr−1), primarily driven by measurements in the southwestern subtropics, and for the North Atlantic Ocean (40±9 versus 10±2 Tg N yr−1). Moreover, version 2 estimates the N2 fixation rate in the Indian Ocean to be 35±14 Tg N yr−1, which could not be estimated using version 1 due to limited data availability. Furthermore, a comparison of N2 fixation rates obtained through different measurement methods at the same months, locations, and depths reveals that the conventional 15N2 bubble method yields lower rates in 69 % cases compared to the new 15N2 dissolution method. This updated version of the database can facilitate future studies in marine ecology and biogeochemistry. The database is stored at the Figshare repository (https://doi.org/10.6084/m9.figshare.21677687; Shao et al., 2022).Additional Authors: Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Douglas G. Capone, Edward J. Carpenter, Nicolas Cassar, Bonnie X. Chang, Dreux Chappell, Yuh-ling Lee Chen, Matthew J. Church, Francisco M. Cornejo-Castillo, Amália Maria Sacilotto Detoni, Scott C. Doney, Cecile Dupouy, Marta Estrada, Camila Fernandez, Bieito Fernández-Castro, Debany Fonseca-Batista, Rachel A. Foster, Ken Furuya, Nicole Garcia, Kanji Goto, Jesús Gago, Mary R. Gradoville, M. Robert Hamersley, Britt A. Henke, Cora Hörstmann, Amal Jayakumar, Zhibing Jiang, Shuh-Ji Kao, David M. Karl, Leila R. Kittu, Angela N. Knapp, Sanjeev Kumar, Julie LaRoche, Hongbin Liu, Jiaxing Liu, Caroline Lory, Carolin R. Löscher, Emilio Marañón, Matthew M. Mills, Wiebke Mohr, Pia H. Moisander, Claire Mahaffey, Robert Moore, Beatriz Mouriño-Carballido, Margaret R. Mulholland, Shin-ichiro Nakaoka, Joseph A. Needoba, Eric J. Raes, Eyal Rahav, Teodoro Ramírez-Cárdenas, Christian Furbo Reeder, Lasse Riemann, Virginie Riou, Julie C. Robidart, Vedula V. S. S. Sarma, Takuya Sato, Himanshu Saxena, Corday Selden, Justin R. Seymour, Dalin Shi, Takuhei Shiozaki, Arvind Singh, Rachel E. Sipler, Jun Sun, Koji Suzuki, Kazutaka Takahashi, Yehui Tan, Weiyi Tang, Jean-Éric Tremblay, Kendra Turk-Kubo, Zuozhu Wen, Angelicque E. White, Samuel T. Wilson, Takashi Yoshida, Jonathan P. Zehr, Run Zhang, Yao Zhang, and Ya-Wei Lu

Prendre les cyanobactéries sur le fait

International audienc

A l'origine du vivant

International audienceThere are close interactions between the Earth's climate and life, and this has been the case since the beginning. By studying the history of life on Earth, we understand that the atmosphere probably created it and that life has not stopped modifying this atmosphere in response to the selection pressures resulting from the major transitions that the Earth has undergone. Life has adapted to perturbations by stabilizing itself through specialization and organization. In addition to being a hymn to marine biodiversity, this book aims to help decision-makers to better understand the role of the blue planet in the climate and the importance of taking it into consideration in each of the political decisions of this 21st century.Il existe des interactions étroites entre le climat terrestre et le vivant et ceci depuis les origines. En étudiant l’histoire de la vie sur Terre, on comprend que l’atmosphère l’a probablement créée et que le vivant n’a pas cessé de modifier cette atmosphère en réaction aux pressions de sélection issues des grandes transitions qu’a subie la Terre. Le vivant s’est adapté aux perturbations en se stabilisant grâce à la spécialisation et à l’organisation.En plus d’un hymne à la biodiversité marine, cet ouvrage a pour objectif d’aider les décideurs à mieux comprendre le rôle de la planète bleue dans le climat et l’importance de la prendre en considération dans chacune des décisions politiques de ce XXIème siècl

Prendre les cyanobactéries sur le fait

International audienc

Prendre les cyanobactéries sur le fait

International audienc

A l'origine du vivant

International audienceThere are close interactions between the Earth's climate and life, and this has been the case since the beginning. By studying the history of life on Earth, we understand that the atmosphere probably created it and that life has not stopped modifying this atmosphere in response to the selection pressures resulting from the major transitions that the Earth has undergone. Life has adapted to perturbations by stabilizing itself through specialization and organization. In addition to being a hymn to marine biodiversity, this book aims to help decision-makers to better understand the role of the blue planet in the climate and the importance of taking it into consideration in each of the political decisions of this 21st century.Il existe des interactions étroites entre le climat terrestre et le vivant et ceci depuis les origines. En étudiant l’histoire de la vie sur Terre, on comprend que l’atmosphère l’a probablement créée et que le vivant n’a pas cessé de modifier cette atmosphère en réaction aux pressions de sélection issues des grandes transitions qu’a subie la Terre. Le vivant s’est adapté aux perturbations en se stabilisant grâce à la spécialisation et à l’organisation.En plus d’un hymne à la biodiversité marine, cet ouvrage a pour objectif d’aider les décideurs à mieux comprendre le rôle de la planète bleue dans le climat et l’importance de la prendre en considération dans chacune des décisions politiques de ce XXIème siècl

A l'origine du vivant

International audienceThere are close interactions between the Earth's climate and life, and this has been the case since the beginning. By studying the history of life on Earth, we understand that the atmosphere probably created it and that life has not stopped modifying this atmosphere in response to the selection pressures resulting from the major transitions that the Earth has undergone. Life has adapted to perturbations by stabilizing itself through specialization and organization. In addition to being a hymn to marine biodiversity, this book aims to help decision-makers to better understand the role of the blue planet in the climate and the importance of taking it into consideration in each of the political decisions of this 21st century.Il existe des interactions étroites entre le climat terrestre et le vivant et ceci depuis les origines. En étudiant l’histoire de la vie sur Terre, on comprend que l’atmosphère l’a probablement créée et que le vivant n’a pas cessé de modifier cette atmosphère en réaction aux pressions de sélection issues des grandes transitions qu’a subie la Terre. Le vivant s’est adapté aux perturbations en se stabilisant grâce à la spécialisation et à l’organisation.En plus d’un hymne à la biodiversité marine, cet ouvrage a pour objectif d’aider les décideurs à mieux comprendre le rôle de la planète bleue dans le climat et l’importance de la prendre en considération dans chacune des décisions politiques de ce XXIème siècl

High abundance of diazotrophic picocyanobacteria (< 3 mu m) in a Southwest Pacific coral lagoon

In the present study we detected unicellular diazotrophic cyanobacteria along a nutrient gradient in New Caledonia's coral lagoon (24 000 km(2)) using whole-cell hybridization of specific Nitro821 probes (TSA-FISH, Tyramide Signal Amplification of Fluorescent In Situ Hybridization). The specificity of this probe was confirmed on cultures and in the natural environment, Surprisingly, the community of Nitro821-targeted cells was numerically dominated by picocyanobacteria (97%, 1 to 1.5 mu m). These organisms were either free living (63%), recovered with the 0.2 to 3 mu m size fraction or associated (37%) to particles or planktonic dinoflagellates from larger size fractions (3 to 10 mu m and >10 mu m). Diazotrophic picocyanobacterial abundance ranged from 3 to 140 cells ml(-1) along the nutrient gradient and was highest at the oligotrophic lagoonal station. These cells may contribute to N-2 fixation from the 10 mu m size fraction (0 to 1.9 nmol N-1 24 h(-1)). In addition, in the middle of the lagoon daylight N-15(2) fixation could explain 78% of N-15(2) fixation over 24 h. The results presented in the present study reveal for the first time a significant concentration of photosynthetic diazotrophs within the marine picoplankton community