نتایج جستجو برای: sterile crusts

تعداد نتایج: 19019  

Journal: :The Science of the total environment 2015
Shubin Lan Li Wu Delu Zhang Chunxiang Hu

Biological soil crusts play important ecological functions in arid and semi-arid regions, while different crust successional patterns appeared in different regions. Therefore in this study, the environmental conditions between Shapotou (with cyanobacterial, lichen and moss crusts) and Dalate Banner (with only cyanobacterial and moss crusts) regions of China were compared to investigate why lich...

2014
Guang-Lei Gao Guo-Dong Ding Bin Wu Yu-Qing Zhang Shu-Gao Qin Yuan-Yuan Zhao Yan-Feng Bao Yun-Dong Liu Li Wan Ji-Feng Deng

BACKGROUND Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. METHODOLOGY/PRINCIPAL FINDINGS To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of succe...

In this study, five sequences of Landsat sensors including MSS, TM, ETM+ and OLI at unequal intervals spanning 42 years between 1973 and 2015, were analyzed to investigate the spatial and temporal variation of salt crusts in Sbzevar playa, central Iran. Landsat satellite imageries and ASTER digital elevation model were prepared, and spatial-temporal analyses were carried out in ENVI and GIS. Fu...

Journal: :Nature 1969

2014
J. G. Zhang X. W. Xu J. Q. Lei S. Y. Li R. L. Hill Y. Zhao

Understanding soil evaporation in reforestation processes in an area of extreme drought is important. We examined the effects of drip-irrigated, high-salinity groundwater on the formation of soil salt crusts and subsequent soil evaporation in the Taklimakan Desert Highway Shelterbelt. Soil evaporation was measured using micro-lysimeters (MLS, 20 cm in length × 10 cm in diameter), and chemical c...

2001
RYUJI ASADA KAZUE TAZAKI

Silica biomineralization associated with unicellular microbes (Cyanidium caldarium) living in strongly acidic hot springs were observed by electron microscopy. The unicellular microbes form green biomats undergoing photosynthesis in Kamuiwakka Falls, Hokkaido, Japan. The hot-spring water is strongly acidic, with pH less than 2, and rich in S. Electron microscopy observations showed that the cel...

1998
R. X. Xu G. J. Qiao

A model is suggested for the bursting x-ray pulsar, GRO J1744-28, where the compact object of the pulsar is proposed to be a strange matter star with crusts. It is suggested that two envelope crusts shield the two polar caps of an accreting strange stars owing to strong polar-cap magnetic fields. GRO J1744-28 might not have a unified crust, but two polar crusts. Bursts are the result of phase t...

1999
Gideon M. Henderson Kevin W. Burton

Ferromanganese crusts record seawater isotope history for several elements useful for paleoceanography. Interpreting crust isotope profiles, however, requires an assessment of the rate of diffusion of each element within the crust. We address this issue using Uand Th-isotope profiles, coupled with concentration measurements of some trace elements whose isotopes are often measured in crusts. A d...

Journal: :Nature 1983

2014
Raeid M. M. Abed Lubos Polerecky Amal Al-Habsi Janina Oetjen Marc Strous Dirk de Beer

We examined soil surface colour change to green and hydrotaxis following addition of water to biological soil crusts using pigment extraction, hyperspectral imaging, microsensors and 13C labeling experiments coupled to matrix-assisted laser desorption and ionization time of flight-mass spectrometry (MALD-TOF MS). The topsoil colour turned green in less than 5 minutes following water addition. T...

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