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.

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 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.

scholarly journals Turbidity Estimation from GOCI Satellite Data in the Turbid Estuaries of China’s Coast

2020 ◽  
Vol 12 (22) ◽  
pp. 3770
Author(s):  
Jiangang Feng ◽  
Huangrong Chen ◽  
Hailong Zhang ◽  
Zhaoxin Li ◽  
Yang Yu ◽  
...  
Keyword(s):  
Yangtze River ◽  
Mean Squared Error ◽  
Yellow River ◽  
River Estuary ◽  
Tidal Height ◽  
Marine Ecology ◽  
Yangtze River Estuary ◽  
Hangzhou Bay ◽  
The Yellow River ◽  
Water Turbidity

Knowledge of the distribution and variation of water turbidity directly represent important information related to the marine ecology and multiple biogeochemical processes, including sediment transport and resuspension and heat transfer in the upper water layer. In this study, a neural network (NN) approach was applied to derive the water turbidity using the geostationary ocean color imager (GOCI) data in turbid estuaries of the Yellow River and the Yangtze River. The results showed a good agreement between the GOCI-derived turbidity and in situ measured data with a determination coefficient (R2) of 0.84, root mean squared error (RMSE) of 58.8 nephelometric turbidity unit (NTU), mean absolute error of 25.1 NTU, and mean relative error of 34.4%, showing a better performance than existing empirical algorithms. The hourly spatial distributions of water turbidity in April 2018 suggested that high turbidity regions were distributed in the Yellow River estuary, Yangtze River estuary, Hangzhou Bay, and coastal waters of Zhejiang Province. Furthermore, the relationship between water turbidity and tide were estimated. A defined turbid zone was defined to evaluate the diurnal variations of turbidity, which has subtle changes at different times. Our results showed an inverse relationship between turbidity and tide over six selected stations, i.e., when the value of turbidity is high, then the corresponding tidal height is usually low, and vice versa. The combined effects of tidal height and tidal currents could explain the phenomena, and other factors such as winds also contribute to the turbidity distributions.

scholarly journals Shifting Feeding Habits During Settlement Among Small Yellow Croakers (Larimichthys polyactis)

2022 ◽  
Vol 8 ◽  
Author(s):  
Yuange Chen ◽  
Weilong Wang ◽  
Wei Zhou ◽  
Fen Hu ◽  
Meiqin Wu
Keyword(s):  
Species Richness ◽  
Body Length ◽  
Environmental Changes ◽  
Feeding Habits ◽  
River Estuary ◽  
The Body ◽  
The Yellow Sea ◽  
Yangtze River Estuary ◽  
Larimichthys Polyactis ◽  
Dietary Breadth

The small yellow croaker, Larimichthys polyactis, is a keystone species in the Yellow Sea and the East China Sea, with significant impacts on the regional ecosystem, but has experienced decades of population decline as a result of environmental changes and overfishing. The settlement of post-larval L. polyactis is a period of high mortality, with impacts on population recruitment and survival. This study examines the feeding habits of 49 post-larval and early juvenile L. polyactis in the Yangtze River estuary, in order to reveal diet composition before and after the settlement period. DNA barcoding methods (MiSeq and TA cloning) were used to examine gastrointestinal contents in detail. Both methods revealed that dietary breadth increased with increasing body length, while the dominance of copepods in the diet decreased as the body length increased. Post-larva (body length < 17 mm in this study) primarily fed on copepods. At the beginning of settlement (body length between 17 and 19 mm), L. polyactis began to ingest larger organisms, such as fishes and mysids, along with copepods. Larger early juveniles (body length > 20 mm) demonstrated a much wider dietary breadth, implying that successful settlement had occurred. Diet species richness in the MiSeq group was significantly greater than species richness in the TA cloning group, making the trend more pronounced within the MiSeq group. This indicates that the MiSeq method was more efficient than TA cloning in this study. We recommend that future research to investigate the feeding habits of fish larvae should combine MiSeq and visual examination methods.

scholarly journals Historical records of eutrophication in Changjiang (Yangtze) River estuary and its adjacent East China Sea

2012 ◽  
Vol 9 (6) ◽  
pp. 6261-6291 ◽  
Author(s):  
F. Cheng ◽  
X. Song ◽  
Z. Yu ◽  
D. Liu
Keyword(s):  
East China Sea ◽  
Yangtze River ◽  
Environmental Changes ◽  
River Estuary ◽  
East China ◽  
Yangtze River Estuary ◽  
Red Tides ◽  
Changjiang River ◽  
Diatom Assemblages ◽  
China Sea

Abstract. Two sediment cores from the Changjiang (Yangtze) River estuary and its adjacent East China Sea were collected and studied for eutrophication history using paleoecological records of environmental changes over the last century. A multiproxy approach by using biological and geochemical analyses revealed changes in diatom assemblages, total organic carbon (TOC), total nitrogen (TN) and biogenic silica (BSi) and give an indication of nutrient in status and trends in Changjiang River estuary and its adjacent East China Sea. The diatom assemblages in the two cores generally increased gradually from the 1970s, and accelerated from the 1990s until now, reflecting the increased eutrophication and causing large algae blooms/red tides. The TOC, TN and BSi showing the similar trends, supported the interpretation of the eutrophication process indicated by diatom analyses. The two cores were located in different sea areas of the East China Sea, and we discuss their relative changes based on their environment characteristics. We also discuss the potential effect of anthropogenic influences and ongoing projects on eutrophication in the Changjiang River and its adjacent East China Sea.

Distribution and risk assessment of trace metals in sediments from Yangtze River estuary and Hangzhou Bay, China

2017 ◽  
Vol 25 (1) ◽  
pp. 855-866 ◽  
Author(s):  
Feipeng Li ◽  
Lingchen Mao ◽  
Yubao Jia ◽  
Zhujun Gu ◽  
Weiling Shi ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Trace Metals ◽  
Yangtze River ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Hangzhou Bay

DIVERSITY OF FISH LARVAE AROUND THE ESTUARY OF THE BANYUASIN RIVER, SOUTH SUMATERA PROVINCE

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Moh. Rasyid Ridho ◽  
Enggar Patriono ◽  
Sarno Sarno ◽  
Sahira Wirda
Keyword(s):  
Initial Phase ◽  
Sampling Method ◽  
Environmental Changes ◽  
Negative Impact ◽  
Fish Larvae ◽  
River Estuary ◽  
Sampling Technique ◽  
Critical Phase ◽  
Morisita Index ◽  
Index Value

The initial phase of the fish life cycle is a critical phase associated with high mortality due to sensitivity to predators, food availability, and also environmental changes that occur in nature. Disruption of the initial stages of fish life has a negative impact on fish populations. Until now there has been no information about fish larvae around the Banyuasin River Estuary. Therefore, research is needed on the diversity of fish larvae around the Banyuasin River Estuary, South Sumatra Province. This research were used purposive sampling method, sampling technique in the form of Cruise Track Design with continuous parallel survey trajectory. Based on the results of the study found as many as 10 families consisting of 1483 individuals of fish larvae in March and 1013 individuals of fish larvae in May consisting of Engraulidae 1,601 individuals of fish larvae, Mungiloidei as many as 109 individuals, Leiognathidae 50 individuals, Chanidae 453 individuals, Scatophagidae 20 individuals , Belonidae 39 individuals, Gobioididae 5 individuals, Chandidae 183 individuals, Syngnatihidae 6 individuals, and Gobiidae 30 individuals fish larvae. The index value of fish larvae diversity is classified as medium category (March 1.02 and May 1.12), Morisita index shows the distribution pattern of fish larvae classified as a group (March 0-14.17 and May 2.43-10.40 ), and the evenness index value is in the medium category (March 0.437 and May 0.521).

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