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dc.contributor.authorLange, Otto L.
dc.contributor.authorGreen, T.G. Allan
dc.date.accessioned2010-01-18T03:23:42Z
dc.date.available2010-01-18T03:23:42Z
dc.date.issued2008
dc.identifier.citationLange, O.L. & Green, T.G.A. (2008). Diel and seasonal courses of ambient carbon dioxide concentration and their effect on productivity of the epilithic lichen Lecanora muralis in a temperate, suburban habitat. The Lichenologist, 40(5), 449-462.en
dc.identifier.issn0024-2829
dc.identifier.urihttps://hdl.handle.net/10289/3529
dc.description.abstractAmbient CO₂ concentration (together with CO₂ exchange and microclimate) was recorded every 30 min for 15 months for Lecanora muralis growing in the Botanical Garden Würzburg (Germany, northern Bavaria), a habitat on the outskirts of the city. Annual mean CO₂ was around 17 ppm higher than the global average reported for the time of measurement (361 ppm; 1995/96), and daily values ranged from 317 to 490 ppm. Diel courses of CO₂ could be classified into three different types. Type A, when CO₂ levels rose overnight and then fell strongly to below global levels during the day, which predominated in the summer (about 75 of days); Type B, irregular diel courses occurred during all seasons with often very rapid changes apparently due to advective CO₂ transport; Type C, CO₂ concentration was typically almost stable at generally between c. 330 and 430 ppm which predominated in the winter (63 of days). Under controlled conditions, CO₂ saturation of net photosynthesis (NP) of L. muralis at optimal hydration and light occurred at around 1000 ppm. NP was also affected by low CO₂ at limiting light and thallus water contents. Based upon these data, we estimated the improvement of NP of L. muralis due to transient increase of ambient CO₂ (as compared with the global average) for one selected combination of environmental factors (nocturnal dew or frost). This combination is an important source of water for the lichen, resulting in 40 of its annual production and, especially in these situations, photosynthesis was increased by high ambient CO₂ in the early morning under prevailing Type A conditions. After dew activation, light compensation point of NP occurred at an average concentration of 413 ppm and diel maxima of NP at 402 ppm. This allows a rough estimate that the transiently elevated CO₂ increased the photosynthetic gain of the lichen after dew of 7, or an improvement to its annual carbon balance of about 3. Conditions, especially interrelationships between lichen hydration, light and CO₂ are so complex that we are not yet able to extend our estimates to other environmental situations of photosynthetic activity of L. muralis.en
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherCambridge University Pressen_NZ
dc.subjectCO₂en
dc.subjectdewen
dc.subjectglobal climate changeen
dc.subjectphotosynthesisen
dc.subjectwater contenten
dc.titleDiel and seasonal courses of ambient carbon dioxide concentration and their effect on productivity of the epilithic lichen Lecanora muralis in a temperate, suburban habitaten
dc.typeJournal Articleen
dc.identifier.doi10.1017/S0024282908007676en
dc.relation.isPartOfThe Lichenologisten_NZ
pubs.begin-page449en_NZ
pubs.elements-id37071
pubs.end-page462en_NZ
pubs.issue5en_NZ
pubs.volume40en_NZ


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