3,502 research outputs found
Partitioning the net CO2 flux of a deciduous forest into respiration and assimilation using stable carbon isotopes
No full textPartitioning net ecosystem CO2 fluxes measured by the eddy covariance technique into their components assimilation and respiration is crucial for predicting future responses and feedbacks of ecosystems to a changing climate. On the basis of an isotopic approach with C-13, we partitioned the daytime net CO2 fluxes of a deciduous forest in central Germany into assimilation and respiration fluxes over a period of 3 weeks. This is the first attempt so far to quantify component fluxes with stable isotopes over the period of 3 weeks, enabling us to investigate the impact of environmental factors on the partitioned fluxes. Large variability in environmental conditions during the 3-week measurement campaign led to strong changes in isotopic disequilibrium between assimilation and respiration, ranging from 1 to 5%. Although this approach is still associated with large uncertainty, we found reasonable patterns in ecosystem respiration and assimilation, and a significant correlation of daytime respiration with soil temperature (R-2 = 0.48). The ratio of respiration to assimilation was highly variable on a day-to-day basis, ranging from 10% to more than 25%. This ratio was mainly controlled by soil temperature (R-2 = 0.61), indicating a strong sensitivity of ecosystem carbon dynamics to temperature changes and higher carbon uptake efficiency during cooler days. [References: 62
Forholdet mellom fugler og vindmøller og andre lufthindringer. En litteraturoversikt
Full text linkNygård, T, Bevanger, K. & Reitan, O. 2008. Forholdet mellom fug-ler og vindmøller og andre lufthindringer. En litteraturoversikt. - NINA Rapport 413. 167 s.
Rapporten er en trykt versjon av en nettbasert referansedatabase om forholdet mellom fugl og flaggermus og vindmøller, kraftledninger, tårn, bygninger og andre lufthindringer. Den er en database som blir jevnilig oppdatert, og som er tilgjengelig over nettet via EndNote Web. Referansedatabasen inneholder i skrivende stund 1224 referanser til litteratur som omhandler denne problematikken. Databasen blir stadig utvidet etter hvert som ny litteratur blir tilgjengelig. Basen kan brukes som søkeverktøy mot andre litteraturdatabaser så som ISI Web of knowledge, Biosis og lignende, avhengig av brukertilgang. . I denne trykte utgaven er referansene sortert tematisk, deretter på trykkeår og forfatter. Basen har fått navnet ”Birdwind”. og oppdateres og administreres av NINA. Basen er ment som er verktøy som gjør det lettere å finne fram til relevant litteratur innenfor disse raskt voksende temaene. database, referanser, internett, EndNote web, fugl, flaggermus, vindmøller, vindkraft, kraftledninger, tårn, bygninger, gjerder, lufthindringer, radar, fugletrekk, kollisjoner, risiko, unnvikelse, økologiske effekter, avbøtende tiltak, litteratur, database, references, internet, EndNote Web, birds, bats, wind-farms, wind energy, turbines, utility structures, towers, buildings, fences, aerial obstacles, collisions, risk, radar, bird migration, avoidance, ecological effects, mitigation measures, literatureNygård, T., Bevanger, K. & Reitan, O. 2008. The relation between birds and wind turbines and other aerial obstacles. A literature survey. - NINA Report 413. 167 pp.
The report is a printed version of an internet-based reference database on the relation between birds and bats and aerial obstacles such as wind turbines, utility structures, towers and buildings. The database will be updated regularly, and is accessible via EndNote Web. At the date of printing it contains 1224 references on these topics. The database can also be used as a search engine for other databases such as ISI Web of knowledge, Biosis and others, depending on the access rights of the user.
In this printed version, the references are sorted by theme, thereafter by year of printing and author. The database is named “Birdwind”, and is administered and updated by NINA. The database is meant to be a tool that will make it easier to find relevant literature within these rapidly growing topics
Environmental variables controlling soil respiration on diurnal, seasonal and annual time-scales in a mixed mountain forest in Switzerland
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Dear SIS Seminar, Nina June Lee, Young Scholar, Fall 2020
Full text linkNina J. Lee is a graduating senior Comparative Women�s Studies Major from Everett, Massachusetts. After Spelman, she will pursue a Masters of Education in Community Engagement with a concentration in Community Organizations and Nonprofit Management
Save the Date: Nina Revoyr, Author Event
Full text linkThis poster was created to promote Loyola Marymount University Common Book 2015 author\u27s visit, Nina Revoyr
Strong coupling of shoot assimilation and soil respiration during drought and recovery periods in beech as indicated by natural abundance δ13C measurements
No full textDrought down-regulates above- and belowground carbon fluxes, however, the resilience of trees to drought will also depend on the speed and magnitude of recovery of these above- and belowground fluxes after re-wetting. Carbon isotope composition of above- and belowground carbon fluxes at natural abundance provides a methodological approach to study the coupling between photosynthesis and soil respiration under conditions (such as drought) that influence photosynthetic carbon isotope discrimination. In turn, the direct supply of root respiration with recent photoassimilates will impact on the carbon isotope composition of soil-respired CO2. We independently measured shoot and soil CO2 fluxes of beech saplings (Fagus sylvatica L.) and their respective δ13C continuously with laser spectroscopy at natural abundance. We quantified the speed of recovery of drought stressed trees after re-watering and traced photosynthetic carbon isotope signal in the carbon isotope composition of soil-respired CO2. Stomatal conductance responded strongly to the moderate drought (-65%), induced by reduced soil moisture content as well as increased vapor pressure deficit. Simultaneously, carbon isotope discrimination decreased by 8‰, which in turn caused a significant increase in δ13C of recent metabolites (1.5-2.5‰) and in δ13C of soil respiration (1-1.5‰). Generally, shoot and soil CO2 fluxes and their δ13C were in alignment during drought and subsequent stress release, clearly demonstrating a permanent dependence of root respiration on recently fixed photoassimilates, rather than on older reserves. After re-watering, the drought signal persisted longer in δ13C of the water soluble fraction that integrates multiple metabolites (soluble sugars, amino acids, organic acids) than in the neutral fraction which represents most recently assimilated sugars or in the δ13C of soil respiration. Nevertheless, full recovery of all aboveground physiological variables was reached within four days –and within seven days for soil respiration – indicating high resilience of (young) beech against moderate drought
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