scholarly journals Effects of Hydrothermal Conditions on the Net Primary Productivity in the Source Region of Yangtze River, China

2020 ◽  
Author(s):  
Zhe Yuan ◽  
Yongqiang Wang ◽  
Jijun Xu ◽  
Jun Yin ◽  
Shu Chen
Keyword(s):  
Soil Water ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Source Region ◽  
Recent Decade ◽  
Ecosystem Dynamics ◽  
Hydrothermal Conditions ◽  
Average Value ◽  
Accumulated Temperature

Abstract Background: The ecosystems and natural environment of the Source Region of Yangtze River (SRYR) is highly susceptible to the climate change. Quantifying the response of vegetation Net Primary Productivity (NPP) to the changes of hydrothermal conditions is an important way to identify and predict global ecosystem dynamics. Methods: Using MODIS/Terra Yearly NPP data at 1km×1km spatial resolution, the spatial-temporal variation of NPP was analyzed at first. Then, correlations between NPP and hydrothermal conditions were evaluated with soil water content and accumulated temperature. Finally, a response model was built to analyze the sensitivity of the NPP to precipitation and temperature changes. Result: (1) NPP is generally lower in the western SRYR and increases gradually toward the east, with an average value of 85.2 gC/m 2 . The total NPP had increased by 1.42TgC per year from 2000 to 2014. The fastest change rate of NPP is presented in the Downstream region, followed by the middle stream region and Dam River Basin; (2) the NPP of one specific year has obvious relationship with the accumulated temperature of the same year and the soil water deficit of the previous year. The temperature is the dominant climate factor impacting vegetation growth in the SRYR; (3) It is shown an increase of NPP by 0.194 TgC (nearly 30%) with a 1-°C increase in annual mean temperature. While a 10% increase in annual precipitation corresponds to an increase in NPP by 0.517 TgC (nearly 5%). Conclusion: A warming, wetting and greening SRYR was detected in recent decade. The NPP in SRYR is more sensitive to changes in temperature than changes in precipitation.

scholarly journals Effects of climatic factors on the net primary productivity in the source region of Yangtze River, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Yuan ◽  
Yongqiang Wang ◽  
Jijun Xu ◽  
Zhiguang Wu
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Source Region ◽  
Primary Reason ◽  
Vegetation Types ◽  
Temperature And Precipitation ◽  
Increasing Trend

AbstractThe ecosystem of the Source Region of Yangtze River (SRYR) is highly susceptible to climate change. In this study, the spatial–temporal variation of NPP from 2000 to 2014 was analyzed, using outputs of Carnegie–Ames–Stanford Approach model. Then the correlation characteristics of NPP and climatic factors were evaluated. The results indicate that: (1) The average NPP in the SRYR is 100.0 gC/m2 from 2000 to 2014, and it shows an increasing trend from northwest to southeast. The responses of NPP to altitude varied among the regions with the altitude below 3500 m, between 3500 to 4500 m and above 4500 m, which could be attributed to the altitude associated variations of climatic factors and vegetation types; (2) The total NPP of SRYR increased by 0.18 TgC per year in the context of the warmer and wetter climate during 2000–2014. The NPP was significantly and positively correlated with annual temperature and precipitation at interannual time scales. Temperature in February, March, May and September make greater contribution to NPP than that in other months. And precipitation in July played a more crucial role in influencing NPP than that in other months; (3) Climatic factors caused the NPP to increase in most of the SRYR. Impacts of human activities were concentrated mainly in downstream region and is the primary reason for declines in NPP.

scholarly journals HUBUNGAN PRODUKTIVITAS PRIMER FITOPLANKTON DENGAN KETERSEDIAAN UNSUR HARA DAN INTENSITAS CAHAYA DI PERAIRAN TELUK KENDARI SULAWESI TENGGARA

2013 ◽  
Vol 13 (2) ◽  
Author(s):  
Nur Irawati, Enan M. Adiwilaga Dan Niken T.M. Prawtiwi
Keyword(s):  
Light Intensity ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
River Mouth ◽  
Sampling Station ◽  
Nutrient Element ◽  
Data Description ◽  
Average Value ◽  
Main Factors ◽  
The Relationship

ABSTRAKPenelitian ini merupakan kajian tentang hubungan produktivitas primer fitoplankton denganketersediaan unsur hara dan intensitas cahaya di perairan Teluk Kendari. Penelitian ini dilaksanakan diPerairan Teluk Kendari pada bulan April – Juni 2009 dengan menempatkan 3 stasiun penelitian.Tujuan penelitian adalah mengkaji hubungan antara produktivitas primer fitoplankton (NPP) denganketersediaan unsur hara dan intensitas cahaya (ICM) di perairan Teluk Kendari. Hasil penelitianmenunjukkan bahwa nilai produktivitas primer selama penelitian pada perairan Teluk Kendari yaitupada stasiun luar teluk berkisar 16,99 – 26,37 mgC/m3/4 jam, pada stasiun tengah teluk 21,09 – 31,25mgC/m3/4 jam, dan 11,13–24,61 mgC/m3/4 jam pada stasiun dalam teluk. Hubungan produktivitasprimer dengan unsur hara dan ICM memperlihatkan keeratan hubungan yang kuat pada ketiga stasiunpenelitian sedang produktivitas primer dengan unsur hara dan ICM menunjukkan pola yang hampirsama pada ketiga stasiun penelitian. Pada stasiun luar teluk, unsur hara amonia dan nitrat bersamaICM menjadi faktor yang memberikan pengaruh nyata terhadap tinggi rendahnya nilai NPP, sedangpada stasiun tengah dan dalam teluk, unsur hara nitrat dan ICM memberikan pengaruh yang nyataterhadap tinggi dan rendahnya nilai NPP di perairan Teluk Kendari.ABSTRACTThe sudy on the Phytoplankton primary productivity relationship to the availability of nutrientelement and light intensity in the waters of Kendari Bay was conducted on April-June 2009 at threesites. The purpose of this research was to examine the relationship between primary productivity ofphytoplankton with nutrient availability and light intensity in the waters of the Bay of Kendari. Basedon the data description and laboratory analysis, net primary productivity values during the surveyperiod varied from 11.13 to 31.25 mgC/m3/4 hour with ranges of average value of NPP from 20.0 to24.46 mgC/m3/4 hour. Sampling station located at the middle of the bay had the highest NPP valuefollowed by sampling station positioned at the mouth of the bay and the lowest value was found atsampling station located near the river mouth of the upper part of the bay. Relationship betweenprimary productivity and light intensity depicted a strong correlation at the three sampling stations.Relationship of primary productivity to nutrient and light intensity showed that the relationship werehigh in all three stations. Similar pattern of relationship were shown among the three stations. At thestation located out of the Kendari Bay, nutrient element N (both ammonia and nitrate) and lightintensity were the main factors that signifacantly influence the level of NPP value, while stationlocated in the middle and inside the bay, results reveal that nitrate and light intensity had significatinflunce on the level of NPP values.Key words: primary productivity of phytoplankton, nutrient elements, light intensity

scholarly journals Changes in Forest Net Primary Productivity in the Yangtze River Basin and Its Relationship with Climate Change and Human Activities

2019 ◽  
Vol 11 (12) ◽  
pp. 1451
Author(s):  
Fengying Zhang ◽  
Zengxin Zhang ◽  
Rui Kong ◽  
Juan Chang ◽  
Jiaxi Tian ◽  
...  
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
River Basin ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Yangtze River Basin ◽  
The Yangtze River ◽  
The Yangtze River Basin ◽  
Lower Yangtze

Net Primary Productivity (NPP) is a basis of material and energy flows in terrestrial ecosystems, and it is also an important component in the research on carbon cycle and carbon budget. This paper evaluated the spatial distribution pattern and temporal change trends for forest NPP simulated by the LPJ (Lund-Potsdam-Jena) model and NDVI (normalized difference vegetation index) in the Yangtze River basin from 1982 to 2013. The results revealed that: (1) the spatial distribution of the forest NPP and NDVI in the Yangtze River basin has gradually decreased from the southeast coast to the northwest. The forest NPP and NDVI in the mid-lower Yangtze were higher than that of the upper Yangtze; (2) the forest NPP and NDVI in most areas of the Yangtze River basin were positively correlated with the temperature and precipitation. Moreover, the correlations among the temperature with the forest NPP and NDVI were stronger than that of correlations among precipitation with forest NPP and NDVI. Moreover, the extreme drought event in the year of 2004–2005 led the NPP to decrease in the middle and lower Yangtze River basin; (3) human activity such as major ecological projects would have a certain impact on the NPP and NDVI. The increase in forest areas from 2000 to 2010 was larger than that from 1990 to 2000. Moreover, the increasing rate for the NDVI was higher than that of NPP, especially after the year 2000, which indicates that the major ecological projects might have great impacts on the vegetation dynamics. Moreover, more attention should be paid on the joint impacts of human activity and climate change on terrestrial NPP and NDVI.

scholarly journals Relationship between net primary productivity and soil water content in the Shule River Basin

CATENA ◽  
2022 ◽  
Vol 208 ◽  
pp. 105770
Author(s):  
Dongxia Yue ◽  
Yanyan Zhou ◽  
Jianjun Guo ◽  
Zengzu Chao ◽  
Xiaojuan Guo
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
River Basin ◽  
Primary Productivity ◽  
Net Primary Productivity

Ecosystem Function and Dynamics

2013 ◽  
Author(s):  
Eric Post
Keyword(s):  
Ecosystem Function ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Ecosystem Respiration ◽  
Net Ecosystem Production ◽  
Ecosystem Dynamics ◽  
Ecosystem Production

This chapter focuses on the distinction between ecosystem function and ecosystem dynamics. Ecosystem function refers to the manner in which the ecosystem of interest works, and interactions among its component parts and fluxes, including biotic and abiotic compartments. Meanwhile, ecosystem dynamics refers to variation in ecosystem function through time in response to perturbations that are continuous or stochastic in nature, or in relation to changes in ecosystem components. Therefore, the study of ecosystem dynamics derives from an understanding of ecosystem function, and this, in turn, depends critically on successful identification of the important drivers within the ecosystem. Inevitably, a discussion of ecosystem function and dynamics boils down to the factors that influence and contribute to variation in net ecosystem production—the result of net primary productivity and ecosystem respiration.

Satellite-based estimation of net primary productivity for southern China’s grasslands from 1982 to 2012

2017 ◽  
Vol 71 (3) ◽  
pp. 187-201 ◽  
Author(s):  
W Yang ◽  
T Lu ◽  
S Liu ◽  
J Jian ◽  
F Shi ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity
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