Studies of chemical and biological processes in the Keum river Estuary, Korea. II. Factors controlling distribution

1988 ◽  
Vol 35 (6) ◽  
pp. 561
Keyword(s):  
River Estuary ◽  
Biological Processes ◽  
Keum River

scholarly journals Contribution of Biological Effects to the Carbon Sources/Sinks and the Trophic Status of the Ecosystem in the Changjiang (Yangtze) River Estuary Plume in Summer as Indicated by Net Ecosystem Production Variations

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1264 ◽  
Author(s):  
Yifan Zhang ◽  
Dewang Li ◽  
Kui Wang ◽  
Bin Xue
Keyword(s):  
Mixed Layer ◽  
Yangtze River ◽  
River Estuary ◽  
Co2 Exchange ◽  
Atmospheric Co2 ◽  
Yangtze River Estuary ◽  
Biological Processes ◽  
Ecosystem Production ◽  
Near Shore ◽  
Exchange Flux

We conducted 24-h real-time monitoring of temperature, salinity, dissolved oxygen, and nutrients in the near-shore (M4-1), front (M4-8), and offshore (M4-13) regions of the 31° N section of the Changjiang (Yangtze) River estuary plume in summer. Carbon dioxide partial pressure changes caused by biological processes (pCO2bio) and net ecosystem production (NEP) were calculated using a mass balance model and used to determine the relative contribution of biological processes (including the release of CO2 from organic matter degradation by microbes and CO2 uptake by phytoplankton) to the CO2 flux in the Changjiang River estuary plume. Results show that seawater in the near-shore region is a source of atmospheric CO2, and the front and offshore regions generally serve as atmospheric CO2 sinks. In the mixed layer of the three regions, pCO2bio has an overall positive feedback effect on the air–sea CO2 exchange flux. The contribution of biological processes to the air–sea CO2 exchange flux (Cont) in the three regions changes to varying extents. From west to east, the daily means (±standard deviation) of the Cont are 32% (±40%), 34% (±216%), and 9% (±13%), respectively. In the front region, the Cont reaches values as high as 360%. Under the mixed layer, the daily means of potential Conts in the near-shore, front, and offshore regions are 34% (±43%), 8% (±13%), and 19% (±24%), respectively. The daily 24-hour means of NEP show that the near-shore region is a heterotrophic system, the front and offshore regions are autotrophic systems in the mixed layer, and all three regions are heterotrophic under the mixed layer.

Sea ice, hydrological, and biological processes in the Churchill River estuary region, Hudson Bay

2008 ◽  
Vol 77 (3) ◽  
pp. 369-384 ◽  
Author(s):  
Z.A. Kuzyk ◽  
R.W. Macdonald ◽  
M.A. Granskog ◽  
R.K. Scharien ◽  
R.J. Galley ◽  
...  
Keyword(s):  
Sea Ice ◽  
River Estuary ◽  
Hudson Bay ◽  
Biological Processes

Degradation of Organophosphorus Pesticides in Coastal Water

1991 ◽  
Vol 74 (5) ◽  
pp. 883-886 ◽  
Author(s):  
Tsen C Wang ◽  
Marisae.E Hoffman
Keyword(s):  
Coastal Water ◽  
Alkaline Hydrolysis ◽  
East Coast ◽  
Organophosphorus Pesticides ◽  
River Estuary ◽  
Ion Concentration ◽  
Biological Processes ◽  
Biological Interaction ◽  
Indian River ◽  
Significant Pathway

Abstract Organophosphorus pesticides, such as malathlon and parathlon, ars considered to be a relatively safe group of pesticide chemicals. Once pesticides ars deposited to the coastal water, they could undergo chemical, photochemical, and biological processes. This study was mads to determine the persistence and dsgradation of both malathlon and parathlon In the Indian River estuary, which is located along the east coast of Florida. Hydrogsn ion concentration, temperature, salinity, and microorganisms affected the persistence of both malathlon and parathlon in the Indian River estuary. Alkaline hydrolysis was ths most competitive pathway for malathlon degradation. Only slight biological and photolytical degradation of malathlon was observed. By contrast, biological interaction was the most significant pathway for parathlon degradation. Alkaline hydrolysis and sunlight photolysis were only secondary pathways In the degradation of parathlon. The half-lives for parathlon and malathlon In the Indian River water (24 ppt salinity; pH 8.16) were 7.84 and 1.65 days, respectively.

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