@Article{AguilosHérBurWagBon:2018:WhDrLo,
author = "Aguilos, Maricar and H{\'e}raultb, Bruno and Burban, Benoit and
Wagner, Fabien Hubert and Bonal, Damien",
affiliation = "{AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de
Guyane-Universit{\'e} des Antilles} and
{AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de
Guyane-Universit{\'e} des Antilles} and
{AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de
Guyane-Universit{\'e} des Antilles} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {Universit{\'e} de Lorraine}",
title = "What drives long-term variations in carbon flux and balance in a
tropical rainforest in French Guiana?",
journal = "Agricultural and Forest Meteorology",
year = "2018",
volume = "253/254",
pages = "114--123",
month = "May",
keywords = "Tropical rainforest, NEE, GPP. Ecosystem respiration, Radiation,
Drought.",
abstract = "A thorough understanding of how tropical forests respond to
climate is important to improve ecosystem process models and to
reduce uncertainties in current and future global carbon balance
calculations. The Amazon rainforest, a major contributor to the
global carbon cycle, is subject to strong intra- and interannual
variations in climate conditions. Understanding their effect on
carbon fluxes between the ecosystem and the atmosphere and on the
resulting carbon balance is still incomplete. We examined the
long-term (over a 12-year period; 20042015) variations in gross
primary productivity (GPP), ecosystem respiration (RE) and net
ecosystem exchange (NEE) in a tropical rainforest in French Guiana
and identified key climatic drivers influencing the changes. The
study period was characterized by strong differences in climatic
conditions among years, particularly differences in the intensity
of the dry and wet seasons, as well as differences in annual
carbon fluxes and balance. Annual average GPP varied from 3384.9 g
C m\−2 yr\‒1 (95% CI [3320.7, 3445.9]) to 4061.2 g C
m\−2 yr\‒1 (95% CI [3980.1, 4145.0]). RE varied even
more than GPP, with a difference of 933.1 C m\−2
yr\‒1 between the minimum (3020.6 g C m\−2
yr\‒1; 95% CI [2889.4, 3051.3]) and maximum (3953.7 g C
m\−2 yr\‒1; 95% CI [3887.6, 4019.6]) values.
Although NEE showed large interannual variability (nine-fold),
from \‒65.6 g C m\−2 yr\‒1 (95% CI
[\‒4.4, \‒126.0]) to \‒590.5 g C m\−2
yr\‒1 (95% CI [\‒532.3, \‒651.6]), the forest
remained a carbon sink over the 12-year period. A combination of
global radiation (Rg), relative extractable water (REW) and soil
temperature (Ts) explained 51% of the daily variations for GPP,
30% for RE and 39% for NEE. Global radiation was always the best
predictor of these variations, but soil water content and
temperature did also influence carbon fluxes and balance.
Seasonally, Rg was the major controlling factor for GPP, RE and
NEE during the wet season. During the dry season, variations in
carbon fluxes and balance were poorly explained by climate
factors. Yet, REW was the key driver of variations in NEE during
the dry season. This study highlights that, over the long-term,
carbon fluxes and balance in such tropical rainforest ecosystems
are largely controlled by both radiation and water limitation.
Even though variations in Rg have a greater impact on these
fluxes, water limitation during seasonal droughts is enough to
reduce ecosystem productivity, respiration and carbon uptake. The
reduced precipitation expected in tropical rainforest areas under
future climatic conditions will therefore strongly influence
carbon fluxes and carbon uptake. This study also highlights the
importance for land surface or dynamic global vegetation models to
consider the main drivers of carbon fluxes and balance separately
for dry and wet seasons.",
doi = "10.1016/j.agrformet.2018.02.009",
url = "http://dx.doi.org/10.1016/j.agrformet.2018.02.009",
issn = "0168-1923",
language = "en",
targetfile = "aguilos_what.pdf",
urlaccessdate = "27 abr. 2024"
}