MM008:
Scaling from diazotroph gene diversity, gene expression, and community composition to N2 fixation rates


Session ID#: 22248

Session Description:
The biogeographic distribution of N2 fixation has been subject to considerable debate in recent years. While traditionally thought to be restricted to the tropical surface ocean, N2 fixation has now been detected in polar regions, and has also been found “missing” in the South Pacific gyre. Moreover, several studies have reported 15N2-tracer-based rates that suggest activity by non-photosynthetic bacteria and archaea in the mesopelagic. Extrapolation of these rates suggests that N2 fixation in the deep ocean may be substantive. However, some reported rates are exceedingly low, raising questions as to minimum quantifiable rates of the 15N2 tracer method in oceanic systems. Moreover, detected nifH gene copy abundances in the mesopelagic appear insufficient to justify measured rates, and evidence for their expression in the mesopelagic depths and below is quasi non-existent.

 

Here we invite submissions that offer insights into the biogeographic distribution of N2 fixation. We encourage submissions that explore relationships between present (DNA) and expressed (mRNA) nifH genes, in relation to N2 fixation rate measurements, as well as studies that develop new approaches for measurements of diazotroph activity and community composition. Such efforts are critical to reconcile the diversity and function of diazotrophic communities and constrain the marine nitrogen cycle.

Primary Chair:  Angelicque E White, Oregon State University, Corvallis, OR, United States
Co-chairs:  Pia Moisander, University of Massachusetts Dartmouth, MA, United States and Julie Granger, University of Connecticut, Department of Marine Sciences, Groton, CT, United States
Index Terms:

4805 Biogeochemical cycles, processes, and modeling [OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL]
4820 Gases [OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL]
4840 Microbiology and microbial ecology [OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL]
4870 Stable isotopes [OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL]
Cross-Topics:
  • BN - Biogeochemistry and Nutrients
  • CT - Chemical Tracers, Organic Matter and Trace Materials
  • PE - Pelagic Ecosystems
    *Use ME: Marine Ecosystems*

Abstracts Submitted to this Session:

Sarah C. Weber1, Rachel Foster2, Hai Doan-Nhu3, Lam Nguyen-Ngoc3, Ajit Subramaniam4, Joseph Peter Montoya5 and Maren Voss6, (1)Leibniz Institute for Baltic Sea Research (IOW), Biological Oceanography, Warnemünde, Germany, (2)Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, Sweden, (3)Institute of Oceanography (ION), Vietnam, (4)Columbia University of New York, LDEO, Palisades, NY, United States, (5)Georgia Inst Technology, Atlanta, GA, United States, (6)Leibniz Institute for Baltic Sea Research Warnemuende (IOW), Biological Oceanography, Rostock, Germany
Rachel E Sipler1, Deborah Ann Bronk2, Kendra Turk-Kubo3, Katie Jean Harding4, Quinn N Roberts1, Mary Katherine Rogener5, Jenna Spackeen1, Brianna Stanley1, Elijah Zane Norton1, Samantha Benton Joye6 and Jonathan P Zehr7, (1)Virginia Institute of Marine Science, Gloucester Point, VA, United States, (2)College William & Mary/VIMS, Gloucester Point, VA, United States, (3)University of California Santa Cruz, Ocean Sciences, Santa Cruz, CA, United States, (4)University of California Santa Cruz, Santa Cruz, CA, United States, (5)University of Georgia, Marine Sciences, Athens, GA, United States, (6)Univ Georgia, Athens, GA, United States, (7)UC Santa Cruz, Ocean Sciences, Santa Cruz, CA, United States
Edo Bar-Zeev, Ben-Gurion University of the Negev, Department of Environmental Hydrology & Microbiology, Zuckerberg Institute for Water Research (ZIWR), Israel and Eyal Rahav, Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel
Noha Hodaed Alsheikh II, University of Hull, Hull, United Kingdom
Lindsey Janel Potts1, Julie Granger1, Craig R Tobias1, Veronica Rose Rollinson1, MAR Benavides2, Pia Moisander3 and Angelicque E White4, (1)University of Connecticut, Department of Marine Sciences, Groton, CT, United States, (2)University of Copenhagen, Marine Biological Section, København K, Denmark, (3)University of Massachusetts Dartmouth, Department of Biology, North Dartmouth, MA, United States, (4)Oregon State University, Corvallis, OR, United States
Mary Rose Gradoville1, Hanna Farnelid2, Angelicque E White3, Kendra Turk-Kubo1 and Jonathan P Zehr1, (1)University of California Santa Cruz, Ocean Sciences, Santa Cruz, CA, United States, (2)Linnaeus University, Sweden, (3)Oregon State University, Corvallis, OR, United States
Katyanne Marie Shoemaker1, Meaghan Christine Daley1, Rodney J Johnson2 and Pia Moisander3, (1)University of Massachusetts Dartmouth, North Dartmouth, MA, United States, (2)BIOS, St Georges, Bermuda, (3)University of Massachusetts Dartmouth, Department of Biology, North Dartmouth, MA, United States
Britt Anderson Henke, Boulder, CO, United States, Kendra A Turk-Kubo, UC Santa Cruz, Ocean Sciences, CA, United States, Sophie Bonnet, Moscow, Russia and Jonathan P Zehr, UC Santa Cruz, Ocean Sciences, Santa Cruz, CA, United States
Bethany D. Jenkins, University of Rhode Island, Cell and Molecular Biology and Graduate School of Oceanography, Narragansett, RI, United States
Pia Moisander, University of Massachusetts Dartmouth, Department of Biology, North Dartmouth, MA, United States, MAR Benavides, University of Copenhagen, Marine Biological Section, København K, Denmark, Katyanne Marie Shoemaker, University of Massachusetts Dartmouth, North Dartmouth, MA, United States, Angelicque E White, Oregon State University, Corvallis, OR, United States, Julie Granger, University of Connecticut, Department of Marine Sciences, Groton, CT, United States and Jaime B Palter, University of Rhode Island, Kingston, RI, United States