Spatial and Temporal Variability of Nitrification Potential and Ammonia-Oxidizer Abundances in Louisiana Salt Marshes
- 601 Downloads
We quantified nitrification potential and ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) abundances in 13 salt marshes in three regions across southeast Louisiana (Terrebonne Bay, western and eastern regions of Barataria Bay). Seven marshes were oiled following the 2010 Deepwater Horizon oil spill, and six sites were unoiled marshes. We evaluated spatial variability by sampling transects from marsh edge to interior, as well as temporal variability across regions. Our nitrification potential rates (up to 5,499 nM NO3-N dry g−1 day−1) were much higher than other published rates for salt marshes and we found strong spatial patterns in both nitrification and soil properties. In Terrebonne soils, nitrification potentials peaked in July and increased from marsh edge to interior. Conversely, rates declined with distance from the marsh edge in western Barataria; no spatial patterns were apparent in eastern Barataria marshes. Spatial patterns corresponded to changes in relative elevation, which also influenced patterns of soil properties and ammonia-oxidizer abundances. Nitrification rates were significantly greater in July than September, though no differences were found between regions within either month. Nitrification potential was positively related to ammonia-oxidizer abundance, and significant relationships were only present in the oiled marshes. In Terrebonne marsh soils, nitrification was more strongly related to AOB abundance whereas rates were more strongly related to AOA abundance in Barataria marsh soils. Although we found strong spatial patterns in nitrification, ammonia-oxidizer abundances, and soil properties that appear to, at least in part, be regulated by differences in elevation and hydrology, we found no significant oil effects 2 years post oil-exposure.
KeywordsNitrification potential Deepwater Horizon oil spill Ammonia-oxidizing archaea Ammonia-oxidizing bacteria Salt marsh
We would like to thank Anya Hopple, Roberta Sheffer, Tiffany Warner, Matthew Rich, and Shauna-Kay Rainford for their help with sample collection and processing; Maggie Marton for editorial assistance; and the comments from the anonymous reviewers who improved this manuscript. Funding was provided by BP/The Gulf of Mexico Research Initiative program through the Coastal Waters Consortium (CWC). The funders had no role in the design, execution, or analyses of this project. Data from this paper is archived at http://dx.doi.org/10.7266/N70Z715C.
- American Public Health Association (APHA). 1992. Standard methods for the examination of water and wastewater, 18th ed. Washington, DC: American Public Health Association.Google Scholar
- Bernhard, A.E., Z.C. Landry, A. Blevins, J.R. de la Torre, A.E. Giblin, and D.A. Stahl. 2010. Abundance of ammonia-oxidizing Archaea and Bacteria along an estuarine salinity gradient in relation to potential nitrification rates. Applied Environmental Microbiology 76: 1285–1289.CrossRefGoogle Scholar
- Caffrey, J.M., N. Bano, K. Kalanetra, and J.T. Hollibuagh. 2007. Ammonia oxidation and ammonia-oxidizing bacteria and archaea from estuaries with differing histories of hypoxia. The International Society for Microbial Ecology Journal 1: 660–662.Google Scholar
- Deni, J., and M.J. Penninckx. 1999. Nitrification and autotrophic nitrifying bacteria in a hydrocarbon-polluted soil. Applied Environmental Microbiology 65: 4008–4013.Google Scholar
- Goolsby, D.A., W.A. Battaglin, G.B. Lawrence, R.S. Artz, B.T. Aulenbach, R.P. Hooper, D.R. Keeney, and G.J. Stensland. 1999. Flux and sources of nutrients in the Mississippi-Atchafalaya River Basin: Topic 3 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico. NOAA Coastal Ocean Program Decision Analysis Series No. 17. NOAA Coastal Ocean Program, Silver Spring, MD. 130 pp.Google Scholar
- IBM® SPSS® Statistics Version 20. 2011. Armonk, New York, USA.Google Scholar
- Peng, X., E. Yando, E. Hildebrand, C. Dwyer, A. Kearney, A. Waciega, I. Valiela, and A.E. Bernhard. 2013. Differential responses of ammonia-oxidizing archaea and bacteria to long-term fertilization in a New England salt marsh. Frontiers in Aquatic Microbiology 3: doi: 10.3389/fmicb.2012.00445.
- Turner, R.E., E.B. Overton, B.M. Ashton, M.S. Miles, G. McClenachan, L. Hooper-Bui, A. Summer-Engel, E.M. Swenson, J.M. Lee, C.S. Milan, and H. Gao. 2014. Distribution and recovery trajectory of Macondo (Mississippi Canyon 252) oil in Louisiana coastal wetlands. Marine Pollution Bulletin 87: 57–67.CrossRefGoogle Scholar
- Vitousek, P.M., J.D. Aber, R.W. Howarth, G.E. Likens, P.A. Matson, D.W. Schindler, W.H. Schlesinger, and D.G. Tilman. 1997. Human alterations to the global nitrogen cycle: sources and consequences. Ecological Applications 7: 737–750.Google Scholar
- Webster, G.T., M. Embley, T.E. Freitag, Z. Smith, and J.I. Prosser. 2005. Links between ammonia oxidizer species composition, functional diversity and nitrification kinetics in grassland soils. Applied Microbiology 7: 676–684.Google Scholar