scholarly journals Spatial Distributions of Picoplankton and Viruses in the Changjiang Estuary and Its Adjacent Sea Area during Summer

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Yun Li ◽  
Daoji Li
Keyword(s):  
Environmental Changes ◽  
Heterotrophic Bacteria ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Nutrient Concentrations ◽  
Viral Abundance ◽  
The Changjiang Estuary ◽  
The Individual ◽  
Sea Area

Simultaneous determination of picoplankton (i.e.,Synechococcusspp.,Prochlorococcusspp., picoeukaryotes, and heterotrophic bacteria) and viruses in the Changjiang (Yangtze) River estuary and its adjacent sea area was made using flow cytometry during a cruise in June 2006. The results show thatProchlorococcusin all samples was below detectable level. The abundances ofSynechococcus, picoeukaryotes, heterotrophic bacteria, and viruses ranged from0.00to1.22×108cell L−1,0.01×106to1.42×107cells L−1,8.40×107to4.29×109cells L−1, and1.20×107to1.06×1010particles L−1, respectively. The determined picoplankton groups and viruses distinctly increased with the distance off the estuary and where the maximum abundance that occurred in these groups was different somewhat due to the individual sensitivity to environmental changes. Viral abundance showed a positive correlation with salinity and negative correlations with turbidity and inorganic nutrient concentrations. Positive linear relations were found betweenSynechococcus, heterotrophic bacteria, and viruses.

Diagnosis of the Operation of Power Plants

2007 ◽  
Author(s):  
Jose´ Miguel Gonza´lez-Santalo´ ◽  
Abigail Gonza´lez-Di´az ◽  
Carlos Alberto Marin˜o-Lo´pez
Keyword(s):  
Power Plants ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
Combined Cycle ◽  
Characteristic Parameters ◽  
Operating Variables ◽  
Design Values ◽  
The Individual ◽  
The Impact

A system was developed to diagnose the operation of combined cycle power plants and to determine, when deviations are found, which components are causing the deviations and the impact of each component deviation. The system works by comparing the values of the actual operating variables with some reference values that are calculated by a model that was adjusted to the design heat balances. The model can use the actual values of the environmental parameters as well as the design values, so the effect of environmental changes can be quantified and separated. The determination of the individual equipment impacts is done by adjusting the equipment parameters in order to reproduce the values of the measured variables. The adjustment is done by varying the values of the characteristic parameters of the equipment in order to minimize the sum of the squares of the differences between the values of the measured variables and the calculated values from the model.

Responses of summer phytoplankton community to drastic environmental changes in the Changjiang (Yangtze River) estuary during the past 50 years

2014 ◽  
Vol 54 ◽  
pp. 1-11 ◽  
Author(s):  
Zhibing Jiang ◽  
Jingjing Liu ◽  
Jianfang Chen ◽  
Quanzhen Chen ◽  
Xiaojun Yan ◽  
...  
Keyword(s):  
Yangtze River ◽  
Phytoplankton Community ◽  
Environmental Changes ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
The Past

scholarly journals Nitrous oxide in the Changjiang (Yangtze River) Estuary and its adjacent marine area: Riverine input, sediment release and atmospheric fluxes

2010 ◽  
Vol 7 (11) ◽  
pp. 3505-3516 ◽  
Author(s):  
G.-L. Zhang ◽  
J. Zhang ◽  
S.-M. Liu ◽  
J.-L. Ren ◽  
Y.-C. Zhao
Keyword(s):  
Nitrous Oxide ◽  
Yangtze River ◽  
River Estuary ◽  
N2o Emission ◽  
Changjiang Estuary ◽  
Yangtze River Estuary ◽  
Emission Rates ◽  
The Changjiang Estuary ◽  
Marine Area ◽  
Key Factor

Abstract. Dissolved nitrous oxide (N2O) was measured in the waters of the Changjiang (Yangtze River) Estuary and its adjacent marine area during five surveys covering the period of 2002–2006. Dissolved N2O concentrations ranged from 6.04 to 21.3 nM, and indicate great temporal and spatial variations. Distribution of N2O in the Changjiang Estuary was influenced by multiple factors and the key factor varied between cruises. Dissolved riverine N2O was observed monthly at station Xuliujing of the Changjiang, and ranged from 12.4 to 33.3 nM with an average of 19.4 ± 7.3 nM. N2O concentrations in the river waters showed obvious seasonal variations with higher values occurring in both summer and winter. Annual input of N2O from the Changjiang to the estuary was estimated to be 15.0 × 106 mol/yr. N2O emission rates from the sediments of the Changjiang Estuary in spring ranged from −1.88 to 2.02 μmol m−2 d−1, which suggests that sediment can act as either a source or a sink of N2O in the Changjiang Estuary. Average annual sea-to-air N2O fluxes from the studied area were estimated to be 7.7 ± 5.5, 15.1 ± 10.8 and 17.0 ± 12.6 μmol m−2d−1 using LM86, W92 and RC01 relationships, respectively. Hence the Changjiang Estuary and its adjacent marine area are a net source of atmospheric N2O.

scholarly journals Nitrous oxide in the Changjiang (Yangtze River) Estuary and its adjacent marine area: riverine input, sediment release and atmospheric fluxes

2010 ◽  
Vol 7 (3) ◽  
pp. 3125-3151 ◽  
Author(s):  
G.-L. Zhang ◽  
J. Zhang ◽  
S.-M. Liu ◽  
J.-L. Ren ◽  
Y.-C. Zhao
Keyword(s):  
Nitrous Oxide ◽  
Yangtze River ◽  
River Estuary ◽  
Changjiang Estuary ◽  
Yangtze River Estuary ◽  
Adjacent Area ◽  
Emission Rates ◽  
The Changjiang Estuary ◽  
Marine Area ◽  
N2o Fluxes

Abstract. Dissolved nitrous oxide (N2O) was measured in the waters of the Changjiang (Yangtze River) Estuary and its adjacent marine area during five surveys covering the period of 2002–2006. Dissolved N2O concentrations ranged from 6.04 to 21.3 nM, and indicate seasonal variations with high values occurring in summer and spring. Dissolved riverine N2O was observed monthly at station Xuliujing of the Changjiang, and ranged from 12.4 to 33.3 nM with an average of 20.8±7.8 nM. The average annual input of N2O from the Changjiang to the estuary and its adjacent area was estimated to be 15.8×106 mol/yr. N2O emission rates from the sediments of the Changjiang Estuary in spring ranged from −1.88 to 2.02 μmol m−2 d−1, which suggest that sediment can act as either a source or a sink of N2O in the Changjiang Estuary. The annual sea to air N2O fluxes from the Changjiang Estuary were estimated to be 6.8±3.7, 13.3±7.2 and 14.9±8.3 μmol m−2 d−1 using LM86, W92 and RC01 relationships, respectively. The annual sea to air N2O fluxes from the adjacent marine area were estimated to be 8.5±7.8, 15.3±13.5 and 17.4&plusmn15.7 μmol m−2 d−1 using LM86, W92 and RC01 relationship, respectively. Hence the Changjiang Estuary and its adjacent marine area is a net source of atmospheric N2O.

Natural and anthropogenic forcing on the dynamics of virioplankton in the Yangtze river estuary

2006 ◽  
Vol 86 (3) ◽  
pp. 543-550 ◽  
Author(s):  
Nianzhi Jiao ◽  
Yanlin Zhao ◽  
Tingwei Luo ◽  
Xiulin Wang
Keyword(s):  
Yangtze River ◽  
Anthropogenic Impacts ◽  
River Estuary ◽  
Distribution Patterns ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
Viral Abundance ◽  
Estuarine Area ◽  
Algal Virus ◽  
River Estuarine

Seasonal investigation of virus dynamics by flow cytometry was conducted in the Yangtze river estuarine area in April, August, November 2002 and February 2003, and a supplemental investigation in the inner estuary and downstream of the river was conducted in October 2005. The majority of the total viral abundance was bacteriophage and only 5.4% of the total was algal virus. Total viral abundance varied with season and location, ranging from 6.75×105–1.68×107 particles/ml, and the virus:bacterium ratio (VBR) ranged from 1.52 to 72.02 with a mean of 8.7. In the present study, viral abundance peaked in both the summer and the winter, unlike the typical seasonal pattern reported in the literature, in which viral abundance peaks in the summer when bacterial hosts are also at their most abundant. However, the driving forces for the two peaks reported here were totally different, the summer viral abundance peak coupled with the development of bacterial hosts which were controlled largely by temperature year-round and by trophic state occasionally, while the winter one seemed to be multi-factor controlled. The host-phage interaction was no longer predominant in control of the winter viral abundance as bacterial abundance was lowest in this season. The winter low temperature would help maintain a high viral abundance as high temperatures might increase viral inactivation and viral decay; the VBR peak values actually occurred in the winter. More importantly, the high virus-containing freshwater discharge in winter due to a higher proportion of anthropogenic sewage relative to low natural flooding in winter run-off, turned out to be the first factor contributing to the high winter viral abundance and VBR values. In addition, the variation of intrusion of warm and relatively oligotrophic water from oceanic currents played a role alternating the distribution patterns of temperature, salinity and trophic conditions and consequently the distribution patterns of virus and bacteria seasonally and spatially. Dynamics of virus in the Yangtze river estuarine area is thus characterized by distinct seasonal and spatial variations due to natural forcing and by pronounced alternation of the regular patterns due to anthropogenic impacts.

scholarly journals Ocean Dynamics Observed by the VIIRS Day-Night Band Measurements

2017 ◽  
Author(s):  
Wei Shi ◽  
Menghua Wang
Keyword(s):  
Infrared Imaging ◽  
Environmental Changes ◽  
River Estuary ◽  
Ocean Dynamics ◽  
Yangtze River Estuary ◽  
Hangzhou Bay ◽  
Algae Bloom ◽  
Coastal Dynamic ◽  
And Migration ◽  
Ocean Environment

Three cases of Day-Night Band (DNB) observations of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) are explored for applications to assess the ocean environment and monitor ocean dynamics. An approach to use the DNB radiance ratio was developed in order to better continuously assess the ocean diurnal and short-term environmental changes with VIIRS DNB observations. In the La Plata River Estuary, the sediment fronts showed 20–25 km diurnal inshore-offshore movements on March 13, 2017. In the waters off the Argentina coast in the South Atlantic, VIIRS DNB measurements provided continuous observations and monitoring of the algae bloom development and migration between 24–26 March 2016. This algae bloom generally kept the same spatial patterns, but moved nearly 20 km eastward in the three-day period. In the Yangtze River Estuary and Hangzhou Bay region in China’s east coast, VIIRS DNB observations also revealed the complicated coastal dynamic changes between 12–14 April 2017. Even though there are still some challenges and limitations for monitoring the ocean environment with VIIRS DNB observations, this study shows that satellite DNB observations can provide additional data sources for ocean observations, especially observations during the nighttime.

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