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| Titel |
Effects of seabird nitrogen input on biomass and carbon accumulation after 50 years of primary succession on a young volcanic island, Surtsey |
| VerfasserIn |
N. I. W. Leblans, B. D. Sigurdsson, P. Roefs, R. Thuys, B. Magnusson, I. A. Janssens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 22 ; Nr. 11, no. 22 (2014-11-17), S.6237-6250 |
| Datensatznummer |
250117678
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| Publikation (Nr.) |
 copernicus.org/bg-11-6237-2014.pdf |
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| Zusammenfassung |
| What happens during primary succession after the first colonizers have
occupied a pristine surface largely depends on how they ameliorate living
conditions for other species. For vascular plants the onset of soil
development and associated increase in nutrient (mainly nitrogen; N) and
water availability is especially important. Here, we report the relationship
between N accumulation and biomass and ecosystem carbon (C) stocks in a
50-year-old volcanic island, Surtsey, Iceland, where N stocks are still
exceptionally low. However, a 28-year-old seagull colony on the island
provided nutrient-enriched areas, which enabled us to assess the
relationship between N stock and biomass and ecosystem C stocks across a
much larger range in N stock. Further, we compared areas on shallow and deep
tephra sands as we expected that deep-rooted systems would be more efficient
in retaining N. The sparsely vegetated area outside the colony had
accumulated 0.7 kg N ha−1 yr−1, which was ca. 50–60% of the
estimated N input rate from wet deposition. This approximates values for
systems under low N input and bare dune habitats. The seagulls have added,
on average, 47 kg N ha−1 yr−1, which induced a shift from
belowground to aboveground in ecosystem N and C stocks and doubled the
ecosystem N-use efficiency, determined as the ratio of biomass and C
storage per unit N input. Soil depth did not significantly affect total N
stocks, which suggests a high N retention potential. Both total ecosystem
biomass and C stocks were strongly correlated with N stock inside the
colony, which indicated the important role of N during the first steps of
primary succession. Inside the colony, the ecosystem biomass C stocks (17–27 ton C ha−1)
had reached normal values for grasslands, while the soil
organic carbon (SOC) stocks (4–10 ton C ha−1 were only a fraction of
normal grassland values. Thus, it will take a long time until the SOC stock
reaches equilibrium with the current primary production, during which
conditions for new colonists may change. |
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