Long-term effects of elevated CO{sub 2} on Mediterranean forest vegetation of Northern-Central Italy

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Bulletin of the Ecological Society of America

OSTI ID:95804

Hinkson, C L; Oechel, W C ^[1]; Miglietta, F ^[2]

---

1. San Diego State Univ., CA (United States)
2. Institute of Environmental analysis and Remote Sensing for Agriculture, Florence (Italy)

Carbon dioxide springs offer a unique opportunity to study the effects of long-term CO{sub 2} enrichment on natural ecosystems. A CO{sub 2} spring near Laiatico (Pisa), Italy vents approximately 25 to 40% of pure CO{sub 2} and enriches about one hectare of a 30-35 year-old coppiced forest, forming a CO{sub 2} gradient with distance from the emission. A:Ci curves were measured on the upper canopy leaves of mature trees of Quercus ilex before bud-break and after new leaf production between April and July 1994. Photosynthetic rates of trees under elevated CO{sub 2} (490 to 1190 ppm) reflect 30-56% downward adjustment in April and no downward adjustment in July. Photosynthetic rates measured at respective growth CO{sub 2} concentrations were reduced in April by 41.8% and enhanced in July by 12.8% as growth CO{sub 2} concentration increased. Leaf nitrogen concentrations under higher CO{sub 2} levels were significantly less than those at ambient CO{sub 2} concentration in April (1.17 and 1.44% N {+-} 0.04%, respectively; P = 0.001). The results from this study indicate that new leaves of mature Quercus ilex may provide a metabolically active carbon sink for enhanced photosynthesis under elevated CO{sub 2}, but after one year, the strength of this sink decreases, resulting in reduced photosynthetic rates and leaf nitrogen concentrations.

• OSTI ID: 95804
• Report Number(s): CONF-9507129--
• Journal Information: Bulletin of the Ecological Society of America, Journal Name: Bulletin of the Ecological Society of America Journal Issue: 2 Vol. 76; ISSN BECLAG; ISSN 0012-9623
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL EFFECTS
CARBON DIOXIDE
CARBON SINKS
CLIMATIC CHANGE
ECOLOGICAL CONCENTRATION
ECOSYSTEMS
ITALY
LEAVES
PHOTOSYNTHESIS
PLANT GROWTH
TREES
VENTS
WATER SPRINGS