Carbon, water, and energy fluxes in a semiarid cold desert grassland during and following multiyear drought
Bowling, D. R.
Lunch, Claire K.
Grote, E. E.
MetadataShow full item record
KeywordPerennial bunchgrass; North American monsoon; Net ecosystem exchange; Hilaria jamesii; Stipa hymenoides
The net exchanges of carbon dioxide, water vapor, and energy were examined in a perennial Colorado Plateau grassland for 5 years. The study began within a multiyear drought and continued as the drought ended. The grassland is located near the northern boundary of the influence of the North American monsoon, a major climatic feature bringing summer rain. Following rain, evapotranspiration peaked above 8 mm d−1 but was usually much smaller (2–4 mm d−1). Net productivity of the grassland was low compared to other ecosystems, with peak hourly net CO2 uptake in the spring of 4 μmol m−2 s−1 and springtime carbon gain in the range of 42 ± 11 g C m−2 (based on fluxes) to 72 ± 55 g C m−2 (based on carbon stocks; annual carbon gain was not quantified). Drought decreased gross ecosystem productivity (GEP) and total ecosystem respiration, with a much larger GEP decrease. Monsoon rains led to respiratory pulses, lasting a few days at most, and only rarely resulted in net CO2 gain, despite the fact that C4 grasses dominated plant cover. Minor CO2 uptake was observed in fall following rain. Spring CO2 uptake was regulated by deep soil moisture, which depended on precipitation in the prior fall and winter. The lack of CO2 uptake during the monsoon and the dependence of GEP on deep soil moisture are in contrast with arid grasslands of the warm deserts. Cold desert grasslands are most likely to be impacted by future changes in winter and not summer precipitation.
Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 115 (2010): G04026, doi:10.1029/2010JG001322.
Showing items related by title, author, creator and subject.
Ralston, David K.; Geyer, W. Rockwell; Lerczak, James A. (American Meteorological Society, 2008-04)A tidally and cross-sectionally averaged model based on the temporal evolution of the quasi-steady Hansen and Rattray equations is applied to simulate the salinity distribution and vertical exchange flow along the Hudson ...
Kida, Shinichiro; Yang, Jiayan; Price, James F. (American Meteorological Society, 2009-02)Marginal sea overflows and the overlying upper ocean are coupled in the vertical by two distinct mechanisms—by an interfacial mass flux from the upper ocean to the overflow layer that accompanies entrainment and by a ...
Helfrich, Karl R.; Grimshaw, Roger H. J. (American Meteorological Society, 2008-03)The disintegration of a first-mode internal tide into shorter solitary-like waves is considered. Since observations frequently show both tides and waves with amplitudes beyond the restrictions of weakly nonlinear theory, ...