Large differences in potential denitrification and sediment microbial communities across the Laurentian great lakes
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Large lakes can efficiently remove reactive nitrogen (N) through denitrification, but nitrate levels in some large oligotrophic lakes are increasing, indicating that denitrification in these lakes is not capable of removing excess N. To better understand how lake trophic status and sediment redox conditions affect the capacity of the microbial community to remove excess N, we measured potential denitrification rates at 86 different stations across Lakes Superior, Huron, Erie, and Ontario. We also relate sediment microbial communities to potential denitrification rates and sediment characteristics for a subset of these sites. In eutrophic/mesotrophic Lake Erie, characterized by sediment with minimal oxygen penetration and relatively high sediment carbon (C) and N, potential denitrification rates were relatively high and increased by 2–3 orders of magnitude in response to additional nitrate and organic C. In contrast, in oligotrophic Lakes Superior and Ontario, and mesotrophic Lake Huron, where oxygen can penetrate several cm into sediment, potential denitrification rates were generally low and did not respond to additional nitrate and organic carbon. Sediment microbial communities showed a similar pattern across this gradient, correlated with potential denitrification rates, sediment %C, and bottom-water nitrate concentrations. This observed relationships between sediment redox conditions, potential denitrification rates, and microbial diversity suggest that sediment microbial communities in these and other oligotrophic large lakes may already be operating at or near their maximum denitrification rates. Unlike mesotrophic Lake Erie, microbial communities in oligotrophic lake sediments may lack the ability to mitigate increases in N loading through denitrification.
KeywordsDenitrification Great Lakes Nitrate Nitrogen Lake Erie Lake Superior Microbial community
We thank the crew of the R/V Blue Heron for their support during this study, and the U.S. Coast Guard, Canadian Coast Guard, and Environment Canada for providing additional sampling opportunities. This material is based upon work supported by the National Science Foundation under Grants OCE-0927512 and OCE-0927277. The work conducted by the U.S. Department of Energy Joint Genome Institute was supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Community Sequencing Project 723.
- Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach, 2nd edn. Springer-Verlag, New YorkGoogle Scholar
- Caporaso JG, Kuczynski J, Stombaugh J, Bittinger K, Bushman FD, Costello EK, Fierer N, Peña AG, Goodrich JG, Gordon JI, Huttley GA, Kelley ST, Knights D, Koenig JE, Ley RE, Lozupone CA, McDonald D, Muegge BD, Pirrung M, Reeder J, Sevinsky JR, Purnbaugh PJ, Walters WA, Widmann J, Yatsunenko T, Zaneveld J, Knight R (2010a) QIIME allows analysis of high-throughput community sequencing data. Nat Methods 7:335–336CrossRefGoogle Scholar
- Dolan DM, Chapra SC (2011) Great lakes total phosphorus loads and models: a fifteen year update. U.S. EPA, Final Report, Grant no. GL 00E58501Google Scholar
- Mulholland PJ, Helton AM, Poole GC, Hall RO, Hamilton SK, Peterson BJ, Tank JL, Ashkenas LR, Cooper LW, Dahm CN, Dodds WK, Findlay SEG, Gregory SV, Grimm NB, Johnson SL, McDowell WH, Meyer JL, Vallett HM, Webster JR, Arango CP, Beaulieu JJ, Bernot MJ, Burgin AJ, Crenshaw CL, Johnson LT, Niederlehner BR, O’Brien JM, Potter JD, Sheibley RW, Sobota DJ, Thomas SM (2008) Stream denitrification across biomes and its response to anthropogenic nitrate loading. Nature 452:202–205CrossRefGoogle Scholar
- R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Sanford RA, Wagner DD, Wu Q, Chee-Sanford JC, Thomas SH, Cruz-García C, Rodríguez G, Massol-Deyá A, Krishnani KK, Ritalahti KM, Nissen S, Konstantinidis KT, Löffler FE (2012) Unexpected nondenitrifier nitrous oxide reductase gene diversity and abundance in soils. Proc Natl Acad Sci USA 109:19709–19714CrossRefGoogle Scholar