Contrasting effects of long term versus short-term nitrogen addition on photosynthesis and respiration in the Arctic
van de Weg, Martine J.
Shaver, Gaius R.
Salmon, Verity G.
MetadataShow full item record
KeywordNitrogen use efficiency; Fertilisation; LTER; Alaska; Chlorophyll; Canopy; Leaf mass per area
We examined the effects of short (<1 to 4 years) and long-term (22 years) nitrogen (N) and/or phosphorus (P) addition on the foliar CO2 exchange parameters of the arctic species Betula nana and Eriophorum vaginatum in northern Alaska. Measured variables included: the carboxylation efficiency of Rubisco (Vcmax), electron transport capacity (Jmax), dark respiration (Rd), chlorophyll a and b content (Chl), and total foliar N (N). For both B. nana and E. vaginatum, foliar N increased by 20-50% as a consequence of 1 to 22 years of fertilisation, respectively, and for B. nana foliar Nincrease was consistent throughout the whole canopy. However, despite this large increase in foliar N, no significant changes in Vcmax and Jmax were observed. In contrast, Rd was significantly higher (>25%) in both species after 22 years of N addition, but not in the shorter-term treatments. Surprisingly, Chl only increased in both species the first year of fertilisation (i.e. the first season of nutrients applied), but not in the longer-term treatments. These results imply that: 1) Under current (low) N availability, these Arctic species either already optimize their photosynthetic capacity per leaf area, or are limited by other nutrients; 2) Observed increases in Arctic NEE and GPP with increased nutrient availability are caused by structural changes like increased leaf area index, rather than increased foliar photosynthetic capacity and 3) Short-term effects (1-4 years) of nutrient addition cannot always be extrapolated to a larger time scale, which emphasizes the importance of long-term ecological experiments.
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Plant Ecology 214 (2013): 1273-1286, doi:10.1007/s11258-013-0250-6.
Suggested CitationPreprint: van de Weg, Martine J., Shaver, Gaius R., Salmon, Verity G., "Contrasting effects of long term versus short-term nitrogen addition on photosynthesis and respiration in the Arctic", 2013-07, https://doi.org/10.1007/s11258-013-0250-6, https://hdl.handle.net/1912/6311
Showing items related by title, author, creator and subject.
Phosphate availability and the ultimate control of new nitrogen input by nitrogen fixation in the tropical Pacific Ocean Moutin, T.; Karl, David M.; Duhamel, Solange; Rimmelin, P.; Raimbault, P.; Van Mooy, Benjamin A. S.; Claustre, Hervé (Copernicus Publications on behalf of the European Geosciences Union, 2008-01-29)Due to the low atmospheric input of phosphate into the open ocean, it is one of the key nutrients that could ultimately control primary production and carbon export into the deep ocean. The observed trend over the last 20 ...
Iron availability limits the ocean nitrogen inventory stabilizing feedbacks between marine denitrification and nitrogen fixation Moore, J. Keith; Doney, Scott C. (American Geophysical Union, 2007-04-04)Recent upward revisions in key sink/source terms for fixed nitrogen (N) in the oceans imply a short residence time and strong negative feedbacks involving denitrification and N fixation to prevent large swings in the ocean ...
Cole, Marci L.; Kroeger, Kevin D.; McClelland, James W.; Valiela, Ivan (2005-07-18)Eutrophication is a major agent of change affecting freshwater, estuarine, and marine systems. It is largely driven by transportation of nitrogen from natural and anthropogenic sources. Research is needed to quantify ...