| 1. |
|
|
| 2. |
- Aerts, R, et al.
(author)
-
Nutritional constraints on Sphagnum-growth and potential decay in northern peatlands
- 2001
-
In: Journal of Ecology. - : Wiley. - 1365-2745 .- 0022-0477. ; 89:2, s. 292-299
-
Journal article (peer-reviewed)abstract
- 1 In a 4-year fertilization experiment we studied the effects of increased nitrogen (N) or phosphorus (P) supply on productivity and potential decay in the acrotelm of Sphagnum-dominated Swedish peatlands at northern (low atmospheric N input: low-N site) and southern (high atmospheric N input: high-N site) sites. 2 During the experimental period, there was a severe summer drought at the high-N site which led to strong limitations on Sphagnum growth, especially in the fertilized treatments. There were no significant effects of the nutrient treatments on cumulative length growth and productivity at either site. There were, however, significant effects of site and nutrient treatment on nutritional variables of the Sphagnum species. 3 Nitrogen concentration in living capitula was lower, but P concentration was higher at the low-N site than at the high-N site. However, at both sites N and P concentration in the living capitula showed only minor responses to the nutrient additions. 4 Litter chemistry variables differed significantly among sites and treatments. Sphagnum litter had lower N concentration, higher P concentration, a higher C : N ratio, a lower C : P ratio and a lower N : P ratio at the low-N site. Litter chemistry was significantly affected by the nutrient treatments only at the high-N site, where litter P concentrations increased significantly in the P-fertilized treatment, whereas C : P and N : P ratios showed a significant reduction. 5 Although potential rates of decay of Sphagnum litter were higher at the high-N site than at the low-N site, they were not significantly affected by nutrient additions. Potential decay rates did, however, show significant relations with all the litter chemistry variables we had determined. 6 An increase in nitrogen input to Sphagnum-dominated bogs appears to lead to higher N concentrations in litter and, as a result of dilution, to lower P concentrations. This change in litter chemistry leads to a higher potential decay rate of the litter and this may seriously affect the carbon balance in the acrotelm of these systems. 7 Our results also show that carbon balance characteristics of Sphagnum bogs can be strongly affected by unpredictable extreme climatic conditions. This suggests that the occurrence and consequences of these events need more attention when long-term responses of ecosystems to global change are studied.
|
|
| 3. |
- Berendse, F, et al.
(author)
-
Raised atmospheric CO2 levels and increased N deposition cause shifts in plant species composition and production in Sphagnum bogs
- 2001
-
In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 7:5, s. 591-598
-
Journal article (peer-reviewed)abstract
- Part of the missing sink in the global CO2 budget has been attributed to the positive effects of CO2 fertilization and N deposition on carbon sequestration in Northern Hemisphere terrestrial ecosystems. The genus Sphagnum is one of the most important groups of plant species sequestrating carbon in temperate and northern bog ecosystems, because of the low decomposability of the dead material it produces. The effects of raised CO2 and increased atmospheric N deposition on growth of Sphagnum and other plants were studied in bogs at four sites across Western Europe. Contrary to expectations, elevated CO2 did not significantly affect Sphagnum biomass growth. Increased N deposition reduced Sphagnum mass growth, because it increased the cover of vascular plants and the tall moss Polytrichum strictum. Such changes in plant species composition may decrease carbon sequestration in Sphagnum-dominated bog ecosystems.
|
|
| 4. |
- Ekholm, M, et al.
(author)
-
Long-term angiotensin-converting enzyme inhibition with ramipril reduces thrombin generation in human hypertension
- 2002
-
In: Clinical science (London, England : 1979). - : Portland Press Ltd.. - 0143-5221 .- 1470-8736. ; 103:2, s. 151-155
-
Journal article (peer-reviewed)abstract
- Antihypertensive treatment reduces the risk of thromboembolic events in hypertension. The aim of this study was to examine the influence of angiotensin-converting enzyme inhibition on blood coagulation in subjects with mild-to-moderate essential hypertension. Fibrinogen, thrombin–antithrombin complex (TAT) and Factor VII were determined in plasma at rest and after a mental stress test following placebo for 6 weeks, or ramipril for 6 weeks or 6 months. Ramipril reduced resting TAT, and tended to reduce fibrinogen; Factor VII remained unchanged. Mental stress increased fibrinogen, but did not alter TAT or Factor VII activity. The reduced thrombin generation in patients taking ramipril may explain in part why angiotensin-converting enzyme inhibitors reduce thromboembolic complications in patients with cardiovascular disease.
|
|
| 5. |
|
|
| 6. |
- Falkengren-Grerup, Ursula, et al.
(author)
-
Förändras floran av kvävenedfallet?
- 2000
-
In: Effekter av kvävenedfall på skogsekosystem. - 9162050664
-
Book chapter (other academic/artistic)abstract
- Abstract is not available
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
