scholarly journals Horizontal distribution characteristics of crustacean planktons and its relationship with environmental factors in Lake Xuanwu, Nanjing City

2012 ◽  
Vol 24 (3) ◽  
pp. 422-428 ◽  
Author(s):  
SUN Ying ◽  
◽  
SHU Tingting ◽  
LI Jing ◽  
DAI Xi ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Horizontal Distribution ◽  
Distribution Characteristics ◽  
Nanjing City ◽  
Lake Xuanwu

scholarly journals Exposure Assessment of Airborne Bacteria Emitted from Swine Manure Composting Plant

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1283
Author(s):  
Ki-Youn Kim
Keyword(s):  
Relative Humidity ◽  
Environmental Factors ◽  
Swine Manure ◽  
Airborne Bacteria ◽  
Particulate Matters ◽  
Distribution Characteristics ◽  
E Coli ◽  
Enterococcus Spp ◽  
Staphylococcus Spp ◽  
Rotary Type

This study was performed to investigate the distribution characteristics of airborne bacteria emitted from swine manure composting plants. The types of swine manure composting plants selected for the survey in this study were as follows: screw type, rotary type, and natural dry type. Mean levels of airborne bacteria in swine manure composting plants were 7428 (±1024) CFU m−3 for the screw type, 3246 (±1407) CFU m−3 for the rotary type, and 5232 (±1217) CFU m−3 for the natural dry type, respectively. Based on the results obtained from this study, the swine manure composting plant operated by screw type showed the highest concentration of airborne bacteria, followed by the natural dry type and rotary type. The monthly concentration of airborne bacteria was the highest in August and the lowest in November, regardless of the type of swine manure composting plant. The respirable size of airborne bacteria accounted for about 50% of the total. The ratio of respirable to the total quantity of airborne bacteria was 50%. The correlation relationships between airborne bacteria and environmental factors (temperature, relative humidity, particulate matters, and odor) were not found to be significant in the swine manure composting plants. The predominant genera of airborne bacteria identified were Micrococcus spp., Staphylococcus spp., Escherichia(E-coli) spp., Enterococcus spp., and Enterobacteriaceae spp.

scholarly journals Research Progress for Dynamic Effects of Cities on Precipitation: A Review

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1355
Author(s):  
Caijun Yue ◽  
Zhihui Han ◽  
Wen Gu ◽  
Yuqi Tang ◽  
Xiangyu Ao
Keyword(s):  
Tropical Cyclones ◽  
Large Scale ◽  
Horizontal Distribution ◽  
Research Progress ◽  
Layer By Layer ◽  
Distribution Characteristics ◽  
Dynamic Effects ◽  
Momentum Exchange ◽  
Extreme Precipitation Events ◽  
The Impact

Citization significantly changes original surface properties. City areas can cause surface winds to decrease; furthermore, ground friction can be transferred layer by layer through the momentum exchange of air movement, which affects the air layers above. Precipitation modification by city environments has been an active research area. Under the conditions of high wind speed, the dynamic effects of cities on precipitation are relatively obvious. Generally, the dynamic effects fall into two main categories: (1) for weather systems under weak forcing synoptic backgrounds, such as local convective systems, shorter-lived extreme precipitation events and fronts and city barrier effects can delay the movement of weather systems, directly change the horizontal distribution characteristics and occurrence time for precipitation, change the flow field and structure, cause the bifurcation of weather systems, and change the horizontal distribution characteristics of precipitation; (2) for weather systems under strong forcing synoptic backgrounds, such as extratropical systems (with large-scale moisture transport), monsoon systems, landfalling tropical cyclones, and supercell storms, the impact of the dynamic effects of cities cannot lead to the bifurcation of the weather system, nor can it change the horizontal distribution characteristics of the whole precipitation field, but it can have an impact on the local precipitation intensity and distribution. However, currently, people do not agree on the impact of cities on precipitation, especially regarding tropical cyclones. Hence, we provide a review and provide insights into the dynamic effects of cities on precipitation.

scholarly journals Understanding the Ecological Response of Planktic and Benthic Epipelic Algae to Environmental Factors in an Urban Rivers System

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1311
Author(s):  
Liling Xia ◽  
Yuelong Zhu ◽  
Zhenhua Zhao
Keyword(s):  
Environmental Factors ◽  
Interaction Mechanism ◽  
Environmental Parameters ◽  
Urban Rivers ◽  
High Concentration ◽  
Variation Characteristics ◽  
Nanjing City ◽  
Spatio Temporal ◽  
One Year ◽  
Autumn And Winter

Many studies have been concentrated on the distribution of algae in lakes, rivers, and seas, however, few studies have been concerned about their distribution and relation with polluted urban rivers. In this study, the spatio-temporal variation characteristics of water quality and algae community in Nanjing city were investigated with microscopic examination for one year. Results showed that the water pollution in this area was mainly related to high concentration of nitrogen (NH3-N and TN (Total nitrogen). There was a total of 77 species of algae in the studied rivers from June 2016 to May 2017, among which 73 species of planktic algae and 34 species of epipelic algae, in which the abundance and biomass of the latter were 1925 and 904 times that of the former, respectively. The two kinds of algae had different change tendencies which were related to seasons. For planktic algae, the abundance and biomass decreased in this season sequence: summer, spring, autumn, and winter. For epipelic algae, the abundance and biomass were relatively higher in winter. The dominant community of planktic algae was Chlorophyta-Bacillariophyceae-Cyanobacteria type, while that of epipelic algae was Bacillariophyceae—Cyanobacteria type. Most of the present algae were bi-trophic species, and were tightly related to the pollution characteristics of the rivers. The key environmental factors for planktic algae are T, TN, and TP, and those for Epipelic algae are N:P and TN. The relation between the community composition of planktic and epipelic algae and environmental parameters are highly complex, and it is worth carrying out further study to clarify their interaction mechanism.

Influence Analysis of Phy-Oceanography Processes for Distribution Characteristics of Dissolved Oxygen in Fujian and Zhejiang Waters

2013 ◽  
Vol 353-356 ◽  
pp. 2755-2762
Author(s):  
Hui Zhang ◽  
Ying Yu Liang ◽  
Bei Zhang ◽  
Pan Jun Du ◽  
Yue Jun Fei
Keyword(s):  
Dissolved Oxygen ◽  
Coastal Upwelling ◽  
Seawater Temperature ◽  
Horizontal Distribution ◽  
Coastal Current ◽  
Distribution Characteristics ◽  
Four Seasons ◽  
Open Sea ◽  
Sea Current ◽  
Different Seasons

Dissolved Oxygen (DO) of sea waters is an important index to ecologic environment of sea. Multidisciplinary surveys were carried out in four seasons from August 2006 to December 2007 in Fujian and Zhejiang waters. Contents of DO in winter and spring were higher than those in summer and autumn. Except for winter, contents of DO show a decreasing trend from surface water to bottom. The overall horizontal distribution of DO In the shore is higher than that of in offshore,but the detailed distribution is different in different seasons. The influence of Physical oceanography processes such as coastal current of Fujian and Zhejiang ,coastal upwelling and the intrusion of open-sea current, on Distribution Characteristics of Dissolved Oxygen was discussed by analyzing hydrologic and meteorologic data. The main conclusions are as follows:The contents of DO is negative correlated with Seawater temperature and salinity. The contents of DO in the shore is high which is impacted by the Yangtze diluted water and coastal current of Fujian and Zhejiang: There are three main reasons why the contents of DO are low in part sea waters of the studied area, which are the intrusion of Taiwan warm current and kuroshio water, the coastal upwelling and the stratification of water.

Planktonic invaders of the St. Lawrence estuarine transition zone: environmental factors controlling the distribution of zebra mussel veligers

2003 ◽  
Vol 60 (10) ◽  
pp. 1245-1257 ◽  
Author(s):  
Christine Barnard ◽  
Jean-Jacques Frenette ◽  
Warwick F Vincent
Keyword(s):  
Environmental Factors ◽  
Transition Zone ◽  
Total Phosphorus ◽  
Dreissena Polymorpha ◽  
Prey Availability ◽  
Larval Fish ◽  
Positive Association ◽  
Horizontal Distribution ◽  
Fish Nursery ◽  
Negative Impacts

The St. Lawrence estuarine transition zone (ETZ) is a productive ecosystem supporting a larval fish nursery. Since 1994, Dreissena polymorpha veligers have become the dominant zooplankton (up to 260 individuals·L–1). The environmental factors controlling their distribution across the ETZ and their potential impact on the plankton were determined. Their horizontal distribution was limited by salinity, with maximum decreases in concentration at 2‰. A sharp decline in prey availability at >2‰ may be a secondary stressor for the veligers, in addition to the direct effects of salinity. Their vertical distribution was homogeneous throughout the water column, even in the presence of a pycnocline. Redundancy analysis showed that veliger concentrations were positively correlated with temperature and turbidity and negatively correlated with salinity and total phosphorus. Veligers were also positively correlated with chlorophyll a and picophytoplankton concentrations, suggesting little effect on their phytoplankton prey. Moreover, the veligers were positively correlated with the sestonic ratio of particulate to total phosphorus, indicating their positive association with good food quality. The veligers appear to have no severe negative impacts on the ETZ plankton community and are restricted to favourable conditions for their survival in the upstream, low salinity region of the ETZ.

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