Geospatial variability of soil CO2-C exchange in the main terrestrial ecosystems of Keller Peninsula, Maritime Antarctica.

Autor: Thomazini A; Departamento de Solos, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais 36570-000, Brazil. Electronic address: andre.thz@gmail.com., Francelino MR; Departamento de Solos, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais 36570-000, Brazil. Electronic address: marcio.francelino@ufv.br., Pereira AB; Universidade Federal do Pampa, São Gabriel, Rio Grande do Sul 97300-000, Brazil. Electronic address: antoniopereira@unipampa.edu.br., Schünemann AL; Departamento de Solos, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais 36570-000, Brazil. Electronic address: adrianoschunemann@gmail.com., Mendonça ES; Departamento de Produção Vegetal, Universidade Federal do Espírito Santo, Alegre, Espírito Santo 29000-000, Brazil. Electronic address: eduardo.mendonca@ufes.br., Almeida PHA; Departamento de Solos, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais 36570-000, Brazil. Electronic address: phalmeida06@gmail.com., Schaefer CEGR; Universidade Federal do Pampa, São Gabriel, Rio Grande do Sul 97300-000, Brazil. Electronic address: carlos.schaefer@ufv.br.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2016 Aug 15; Vol. 562, pp. 802-811. Date of Electronic Publication: 2016 Apr 22.
DOI: 10.1016/j.scitotenv.2016.04.043
Abstrakt: Soils and vegetation play an important role in the carbon exchange in Maritime Antarctica but little is known on the spatial variability of carbon processes in Antarctic terrestrial environments. The objective of the current study was to investigate (i) the soil development and (ii) spatial variability of ecosystem respiration (ER), net ecosystem CO2 exchange (NEE), gross primary production (GPP), soil temperature (ST) and soil moisture (SM) under four distinct vegetation types and a bare soil in Keller Peninsula, King George Island, Maritime Antarctica, as follows: site 1: moss-turf community; site 2: moss-carpet community; site 3: phanerogamic antarctic community; site 4: moss-carpet community (predominantly colonized by Sanionia uncinata); site 5: bare soil. Soils were sampled at different layers. A regular 40-point (5×8 m) grid, with a minimum separation distance of 1m, was installed at each site to quantify the spatial variability of carbon exchange, soil moisture and temperature. Vegetation characteristics showed closer relation with soil development across the studied sites. ER reached 2.26μmolCO2m(-2)s(-1) in site 3, where ST was higher (7.53°C). A greater sink effect was revealed in site 4 (net uptake of 1.54μmolCO2m(-2)s(-1)) associated with higher SM (0.32m(3)m(-3)). Spherical models were fitted to describe all experimental semivariograms. Results indicate that ST and SM are directly related to the spatial variability of CO2 exchange. Heterogeneous vegetation patches showed smaller range values. Overall, poorly drained terrestrial ecosystems act as CO2 sink. Conversely, where ER is more pronounced, they are associated with intense soil carbon mineralization. The formations of new ice-free areas, depending on the local soil drainage condition, have an important effect on CO2 exchange. With increasing ice/snow melting, and resulting widespread waterlogging, increasing CO2 sink in terrestrial ecosystems is expected for Maritime Antarctica.
(Copyright © 2016 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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