Dynamics and fluxes of dissolved carbon under short-term climate variabilities in headwaters of the Changjiang River, draining the Qinghai-Tibet Plateau

2021 ◽  
Vol 596 ◽  
pp. 126128
Author(s):  
Jun Zhong ◽  
Si-Liang Li ◽  
Xuetao Zhu ◽  
Jing Liu ◽  
Sen Xu ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Changjiang River ◽  
Short Term ◽  
Dissolved Carbon ◽  
The Changjiang River ◽  
Qinghai Tibet Plateau

Variation Characteristics of Sunshine Time in Changjiang River Valley in Recent 50 Years

2011 ◽  
Vol 71-78 ◽  
pp. 3137-3141 ◽  
Author(s):  
Shi Gang Han
Keyword(s):  
Sichuan Basin ◽  
Sunshine Duration ◽  
River Valley ◽  
Seasonal Difference ◽  
Tibet Plateau ◽  
Changjiang River ◽  
Time Data ◽  
The Changjiang River ◽  
Variation Characteristics ◽  
Qinghai Tibet Plateau

By using the sunshine time data from 260 meteorological observation stations in Changjiang river valley from 1960 to 2009, the features of sunshine time in this area are studied. The results show that the highest sunshine time place is Qinghai-Tibet Plateau which is located in the source of the Changjiang river, and the sunshine time is about 2200-3000 h.a-1. The lowest sunshine time place is Sichuan Basin , and the sunshine time is about 1000-1600 h.a-1. The place of middle sunshine time is the midstream and down stream of Changjiang river, and the sunshine time is about 2000 h.a-1. There is a trend of decreasing with the sunshine time in zone 1, and the value is 54.2 h.10a-1. The decreasing value of zone 2 is 38.3h.10a-1. There is a trend of “rise first, down after” with sunshine time in zone 3. There is obvious seasonal difference in sunshine duration，with bigger decreasing amplitude in summer and winter than that in autumn. The variation trend of sunshine time is not obvious in spring.

scholarly journals Rapid response of arbuscular mycorrhizal fungal communities to short-term fertilization in an alpine grassland on the Qinghai-Tibet Plateau

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2226 ◽  
Author(s):  
Xingjia Xiang ◽  
Sean M. Gibbons ◽  
Jin-Sheng He ◽  
Chao Wang ◽  
Dan He ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Illumina Miseq ◽  
Tibet Plateau ◽  
Available Phosphorus ◽  
Short Term ◽  
Amf Diversity ◽  
Amf Communities ◽  
Arbuscular Mycorrhizal Fungal ◽  
The Impact ◽  
Qinghai Tibet Plateau

Background:The Qinghai-Tibet Plateau (QTP) is home to the vast grassland in China. The QTP grassland ecosystem has been seriously degraded by human land use practices and climate change. Fertilization is used in this region to increase vegetation yields for grazers. The impact of long-term fertilization on plant and microbial communities has been studied extensively. However, the influence of short-term fertilization on arbuscular mycorrhizal fungal (AMF) communities in the QTP is largely unknown, despite their important functional role in grassland ecosystems.Methods:We investigated AMF community responses to three years of N and/or P addition at an experimental field site on the QTP, using the Illumina MiSeq platform (PE 300).Results:Fertilization resulted in a dramatic shift in AMF community composition and NP addition significantly increased AMF species richness and phylogenetic diversity. Aboveground biomass, available phosphorus, and NO3−were significantly correlated with changes in AMF community structure. Changes in these factors were driven by fertilization treatments. Thus, fertilization had a large impact on AMF communities, mediated by changes in aboveground productivity and soil chemistry.Discussion:Prior work has shown how plants often lower their reliance on AMF symbioses following fertilization, leading to decrease AMF abundance and diversity. However, our study reports a rise in AMF diversity with fertilization treatment. Because AMF can provide stress tolerance to their hosts, we suggest that extreme weather on the QTP may help drive a positive relationship between fertilizer amendment and AMF diversity.

Effects of ocean acidification and short-term light/temperature stress on biogenic dimethylated sulfur compounds cycling in the Changjiang River Estuary

2019 ◽  
Vol 16 (3) ◽  
pp. 197 ◽  
Author(s):  
Shan Jian ◽  
Jing Zhang ◽  
Hong-Hai Zhang ◽  
Gui-Peng Yang
Keyword(s):  
Ocean Acidification ◽  
Dimethyl Sulfide ◽  
River Estuary ◽  
Sulfur Compounds ◽  
Changjiang River ◽  
Changjiang River Estuary ◽  
Short Term ◽  
Chl A ◽  
The Changjiang River ◽  
The Changjiang River Estuary

Environmental contextContinuous anthropogenic CO2 emissions have led to an increase in seawater acidity, potentially affecting the growth of phytoplankton and their production of the climate-moderating biogenic gas, dimethyl sulfide. Our simulation experiments showed that ocean acidification, coupled with light and temperature changes, had a significant influence on dimethyl sulfide concentrations. This research provides fundamental data for predicting the biogeochemical cycle of dimethyl sulfide under various global change scenarios. AbstractOcean acidification (OA) affects marine primary productivity and community structure. Therefore, OA may influence the biogeochemical cycles of volatile biogenic dimethyl sulfide (DMS), and its precursor dimethylsulfoniopropionate (DMSP) and photochemical oxidation product dimethyl sulfoxide (DMSO). A 23-day shipboard incubation experiment investigated the short-term response of the production and cycling of biogenic sulfur compounds to OA in the Changjiang River Estuary to understand the effects of OA on biogenic sulfur compounds. Phytoplankton abundance and community composition showed a marked difference at three different pH levels at the late stage of the experiment. Significant reductions in chlorophyll a (Chl-a), DMS, particulate DMSP (DMSPp) and dissolved DMSO (DMSOd) concentrations were identified under high CO2 levels. Moreover, minimal changes were observed in the productions of dissolved DMSP (DMSPd) and particulate DMSO (DMSOp) among the treatments. The ratios of DMS, total DMSP (DMSPt) and total DMSO (DMSOt) to Chl-a were not affected by a change in pH. Furthermore, the concentrations of DMS and DMSOd were closely related to the mean bacterial abundance at the three pH levels. Additional short-term (8h) incubation experiments on the light and temperature effects showed that the influence of pH on the production of dimethylated sulfur compounds also depended on solar radiation and temperature. Under natural and UVB light, DMS photodegradation rates increased by 1.6 to 4.2 times at low pH levels. Thus, OA may lead to decreasing DMS concentrations in surface seawater. Light and temperature conditions also play important roles in the production and cycling of biogenic sulfur compounds.

scholarly journals Nitrogen retention patterns and their controlling factors in an alpine meadow: implications for carbon sequestration

2007 ◽  
Vol 4 (4) ◽  
pp. 2641-2665 ◽  
Author(s):  
X. L. Xu ◽  
H. Ouyang ◽  
G. M. Cao
Keyword(s):  
Alpine Meadow ◽  
Nitrogen Retention ◽  
Tibet Plateau ◽  
Short Term ◽  
Organic Carbon Concentration ◽  
Long Term Retention ◽  
Abiotic And Biotic Factors ◽  
One Year ◽  
Qinghai Tibet Plateau

Abstract. We hypothesized that the patterns of NO3− and NH4+ retention are different over short-term scales while they are similar over long-term scales in alpine meadows and that abiotic and biotic factors might be responsible for their different patterns over short-term scales. In order to test the hypotheses, a 15N-labeled experiment was conducted in an alpine meadow in the Qinghai-Tibet Plateau over four years. Our results showed that 15NO3− and 15NH4+ retention was distinctly different within two months, and even one year after tracer additions. The long-term retention of 15N at the whole-plot level did not differ significantly between 15NH4+ and 15NO3− treatments, and averaged 50% after four years. Higher soil temperature or soil organic carbon concentration enhanced 15NH4+ retention, but significantly reduced 15NO3− retention in the soil within two months following tracer additions. Soil moisture significantly affected 15N recovered in soil organic matter and microbial biomass as well as aboveground parts, but had no significant effects on 15N recovered in roots. These findings have important ecological implications with regard to the consequences of deposited nitrogen because of the possible difference in the fate of NH4+ vs. NO3− in alpine meadow ecosystems.

scholarly journals Importance of active layer freeze-thaw cycles on the riverine dissolved carbon export on the Qinghai-Tibet Plateau permafrost region

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7146 ◽  
Author(s):  
Chunlin Song ◽  
Genxu Wang ◽  
Tianxu Mao ◽  
Xiaopeng Chen ◽  
Kewei Huang ◽  
...  
Keyword(s):  
Active Layer ◽  
Carbonic Acid ◽  
Tibet Plateau ◽  
Vegetation Coverage ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Carbon Export ◽  
Dissolved Carbon ◽  
Total Runoff ◽  
Qinghai Tibet Plateau

The Qinghai-Tibet Plateau (QTP) is experiencing severe permafrost degradation, which can affect the hydrological and biogeochemical processes. Yet how the permafrost change affects riverine carbon export remains uncertain. Here, we investigated the seasonal variations of dissolved inorganic and organic carbon (DIC and DOC) during flow seasons in a watershed located in the central QTP permafrost region. The results showed that riverine DIC concentrations (27.81 ± 9.75 mg L−1) were much higher than DOC concentrations (6.57 ± 2.24 mg L−1). DIC and DOC fluxes were 3.95 and 0.94 g C m−2 year−1, respectively. DIC concentrations increased from initial thaw (May) to freeze period (October), while DOC concentrations remained relatively steady. Daily dissolved carbon concentrations were more closely correlated with baseflow than that with total runoff. Spatially, average DIC and DOC concentrations were positively correlated with vegetation coverage but negatively correlated with bare land coverage. DIC concentrations increased with the thawed and frozen depths due to increased soil interflow, more thaw-released carbon, more groundwater contribution, and possibly more carbonate weathering by soil CO2 formed carbonic acid. The DIC and DOC fluxes increased with thawed depth and decreased with frozen layer thickness. The seasonality of riverine dissolved carbon export was highly dependent on active layer thawing and freezing processes, which highlights the importance of changing permafrost for riverine carbon export. Future warming in the QTP permafrost region may alter the quantity and mechanisms of riverine carbon export.

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