uid=BNZ,o=lter,dc=ecoinformatics,dc=org all public read knb-lter-bnz.150.11 Jen S Mitchell

Institute of Arctic Biology University of Alaska Fairbanks P.O. Box 757000 Fairbanks AK 99775 United States

(907) 474-7153 jennifersmitchell@gmail.com Bonanza Creek LTER Data Manager

Boreal Ecology Cooperative Research Unit University of Alaska Fairbanks P.O. Box 756780 Fairbanks AK 99775 USA

907-474-6364 907-474-6251 jpdowning@alaska.edu http://www.lter.uaf.edu Roger W. Ruess Professor of Biology

Institute of Arctic Biology University of Alaska Fairbanks P.O. Box 757000 Fairbanks AK 99775-0180 United States

(907) 474-7153 (907) 474-6967 Associated investigator 2005-11-20 We measured rates of nitrogen fixation by Alnus viridis spp. fruticosa and concurrent subcanopy soil temperature at BNZ LTER. To do so we utilized replicate (n=3/stage) stands of a seral sequence of successional stages maintained by the Bonanza Creek Long-Term Ecological Research program (BNZ LTER). At each of the 9 replicate stands we selected a total of 70 individual shrubs. During each of 7 sampling periods, 3 across the growing season of 1997 and 4 during 1998, we randomly selected 10 of 70 A. viridis spp. fruticosa at each replicate stand. We used acetylene reduction assays (ARA) to estimate rates of N2 fixation at each of the selected shrubs and concurrently measured soil temperature at each shrub. The attached database may be utilized to (1) elucidate seasonal trends in rates of N2 fixation by A. viridis spp. fruticosa across a boreal forest chronosequence and (2) investigate soil temperature controls over rates of N2 fixation. It may also be used to statistically analyze differences between years, successional stages and replicates within successional stage in both rates of ARA and temperature. We developed this database to describe seasonal trends of rates of nitrogen fixation by A. viridis spp. fruticosa across a boreal forest chronosequence and to elucidate soil temperature controls over rates. nitrogen cycling soil temperature nitrogen fixation secondary succession alder Biogeochemistry

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http://www.lter.uaf.edu/data_detail.cfm?datafile_pkey=150 Site information unavailable -148.3599027 -148.2446238 64.7666796 64.68945831 1997-06-03 1998-09-25

Completed

Bonanza Creek LTER Data Manager

Boreal Ecology Cooperative Research Unit University of Alaska Fairbanks P.O. Box 756780 Fairbanks AK 99775 USA

907-474-6364 907-474-6251 jpdowning@alaska.edu http://www.lter.uaf.edu Bonanza Creek LTER

Boreal Ecology Cooperative Research Unit University of Alaska Fairbanks P.O. Box 756780 Fairbanks AK 99775 USA

907-474-6364 907-474-6251 Bonanza Creek LTER

At each of the 9 replicate stands we selected a total of 70 individual shrubs. During each of 7 sampling periods, 3 and 4 across the growing seasons of 1997 and 1998 respectively, we randomly selected 10 of 70 A. viridis spp. fruticosa at each replicate

150_NfixSoilTemp.txt We developed this database to describe seasonal trends of rates of nitrogen fixation by A. viridis spp. fruticosa across a boreal forest chronosequence and to elucidate soil temperature controls over rates. 150_NfixSoilTemp.txt 1 \n \n column \t http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-bnz..&urlTail=/ascii/files/150_NfixSoilTemp.txt Year Year The year at which measurement was made integer yy Replicate/siteID Replicate/siteID the replicate used in the study identified by the unique site id integer integer the replicate used in the study identified by the unique site id integer julian julian The day at which the meaurement was made julian 0 integer ddd treenumber treenumber Treenumber: The randomly selected tree at which the measurements were made integer Treenumber: The randomly selected tree at which the measurements were made ARA ARA The index of nitrogen fixation, ARA = acetylene reduction assay Specific ARA expressed as: µmol float µmol real -9999 Missing Value soiltemperature10cm soiltemperature10cm soil temperature as measured under the alder canopy at 10 cm soil depth float celsius real -9999 Missing Value