Water Security-based Hydrological Regime Assessment Method for Lakes with Extreme Seasonal Water Level Fluctuations：A Case Study of Poyang Lake,China

Extreme seasonal water level fluctuations characterize natural floodplain lakes in monsoon regions, which are crucial for ensuring lake water security, including flood prevention water supply and health of aquatic ecosystem. In order to achieve this goal, we established a hydrological regime assessment method based on a set of hydrological indicators for lakes with heavy seasonal water level fluctuations. The results suggest that time-sensitive hydrological indicators and specific time scales for various water security aspects must be considered. We discovered that it is more practical and meaningful to combine the water level classification derived from statistical analyses with characteristic hydrological values linked to water security. The case study of Poyang Lake results show that there are no discernable trends of Poyang Lake water regime status over the last 35 years, and the two periods of poor status are in accordance with climate variation in the lake basin area. Scholars and policy makers should focus on both floods and droughts, which are the main water security problems for Poyang Lake. It is hoped that this multi-scale and multi-element hydrological regime assessment method will provide new guidelines and methods for other international scholars of river and lake water assessment.

Seasonal fluctuation of Myxobolus gibelioi (Myxosporea) plasmodia in the gills of the farmed allogynogenetic gibel carp in China

The seasonal fluctuation of the plasmodia ofMyxobolus gibelioiWu et Wang, 1982 in the gill filaments of the allogynogenetic gibel carpCarassius auratus gibelio(Bloch) in a fish pond in Hubei Province of China was investigated from August 1999 to July 2000. A total of 445 fish was examined; the overall prevalence of the plasmodium infection in the fish was 64.94% and mean abundance of plasmodia was 11.65 ± 27.85 (mean ± SD). Significant seasonal changes in prevalence and mean abundance, with higher levels of the plasmodia infection from late spring to autumn, were observed.

Oceans, Ice &Snow and CO2 Rise, Swing and Seasonal Fluctuation

Carbon dioxide rise, swing and spread (seasonal fluctuations) are addressed in this study. Actual CO2 concentrations were used rather than dry values. The dry values are artificially higher because water vapor must be removed in order for the NDIR instrument to work and is not factored back into the reported numbers. Articles addressing these observations express opinions that are divergent and often conflicting. This investigation resolves many of those inconsistencies. The data were obtained from many measuring stations at various latitudes since 1972 and then graphical compared to changes in sea temperatures, fossil fuel emissions, humidity, and seasonal ice and snow changes. In analyzing the data, various parameters were addressed including: variability, R squared curve values, correlations between curves, residence times, absorption percentages, and Troposphere effects. Mass balance calculations were also made to corroborate viability. The CO2 “rise” over a 33-year period from a slight ocean temperature increase (0.7°F) contributed 2.3 percent of the total rise while fossil fuel emissions contributed 1.5 percent. The overwhelming majority (60 ppmv, 96%+) was caused by other factors including ocean and land biology as well potential errors in fundamental hypotheses. With respect to “spread” (seasonal CO2 fluctuations) at the Polar Circles, graphical analysis with high correlations supported by mass balance calculations confirm that ice and snow are the primary cause and explain why the concentrations are the highest at these cold locations. The global variations in “swing” remain uncertain.

Monitoring Report on Mosquitoes at Ports of Four Regions in East China during 2011—2014

[Objective] The aim was to understand the species composition, distribution, density, seasonal fluctuation and pathogens of mosquitoes in four regions of East China to provide basic data for prevention and control of mosquitoes at ports. [Method] The mosquitoes at 21 ports of four regions in East China were investigated during 2011-2014 by CO2 lamp method, egg collection method, scoop method and visual method. The species of mosquitoes was identified, and pathogens in mosquitoes were detected. [Result] From 2011 to 2014, 102 583 mosquitoes were captured at the ports, belonging to 18 species, 6 genera and 1 family. Culex pipi- ens quinquefasciatus or Culex pipiens pallens was the dominant species at most ports. Mosquitoes could be captured from May to October, and the captured mosquitoes were the most in June. The positive rate of egg collectors was 9.41%, and the positive rate of breeding places was 7.23%. Rare entry mosquitoes were captured, and most of them were C. pipiens pallens. The detection results of dengue fever, malaria and other pathogens were negative. [Conclusion] C. pipiens quinquefasciatus or C. pipiens pallens was dominant at most ports, and the peak period was June. There were breeding environments of mosquitoes at some ports, so the prevention and control of mosquitoes at these ports should be paid more at- tention to in future.

Study of phytoplankton community in the channel from Dongting Lake to Changjiang River, China

Phytoplankton cell density, biomass, chl-α concentration and their seasonal fluctuations at five stations in the channel between Dongting Lake and the Changjiang （Yangtze） River were studied from May 1995 to December 1997. The seasonal fluctuations had two peaks in a year in general. The annual patterns of total cell density and biomass indicated that diatoms contributed more than 70 percent of the total biomass （except from June to October） during the investigation period. Twenty-one dominant species contributed about 60--80 percent of the biomass in various months. The cell density, biomass and seasonal fluctuation were similar at Stations 1-4, but at Station 5 connected directly with the Changjiang River, the annual mean values （127.34×10^4cells/L and 0.46 mg/L in 1996, 41.98×10^4ceUs/L and 0.2 mg/L in 1997 respectively） were lower than those （ 195.92× 10^4 cells/L and 0.5 mg/L in 1996, 132.96 ×10^4 cells/L and 0.57 mg/L in 1997 respectively） at Station 1-4; and the curve of the seasonal fluctuation sometimes did not coincide with those at Stations 1-4. Based on criteria for evaluating trophic status, the dominant species, annual average cell density values of 114.86× 10^4-179.57× 10^4 cells/L, biomass of 0.48-0.5 mg/L, chl-αconcentration of 0.42-0.51 μg/L respectively recorded at five stations in 1996 and 1997, and values associated with the physico-chemical properties of the waterbody indicated that the water in the channel could be characterized as oligo-mesotrophic.

Temperature and Precipitation Fluctuation of Madinah-Al-Munawara, Kingdom of Saudi Arabia (1959-2011)

The work discusses the temperature and precipitation fluctuation of Madinah-Al-Munawara, Saudi Arabia for a time period of 1959-2011. This is a city in the Hejaz region of western Saudi Arabia, the capital of Al Madinah Province and important religious place. For many years now, Royal Kingdom of Saudi Arabia is active on national as well as international levels to adopt a more suitable policy for the study of climate changes and reviews it periodically as per country economic desires. The main sectors that affect the temperature and precipitation fluctuations in Saudi Arabia are surface water, coastal management, overgrazing, forestry, livestock, drought, desertification, industrialization, landuse change, tourism, and aridity etc. The paper analyzes the temperature and precipitation fluctuations of Madinah-Al-Munawara in terms of general climatology, climate fluctuation/variation, seasonal distribution and extreme weather events. The mean monthly temperature of the city recorded during 1959-2011 is 28°C having mean maximum temperature of 34°C and mean minimum of 21°C. The mean monthly temperature of the city shows an increase of 1.7°C having 1.2°C increase in maximum temperature and decrease of -1.9°C in minimum temperature. Generally, there is a rise and fall in the temperature condition and shows irregular pattern throughout the period. The total precipitation of the city is 36 millimeters;having a decrease of -0.3 millimeters but in general the trend of precipitation at Madinah-Al-Munawara shows an increasing trend throughout the period. April and November are the wettest, while June, August, September and October are the hottest months of the city. The area is characterized by two main seasons that is winter (5 months) and summer (7 months), which can further be sub-divided into four rainy seasons namely winter, post-winter, summer, and post-summer seasons.

Phytoplanktonic desmids community in Donghu Lake, Wuhan, China

For compilation and comparison of desmids flora, the authors restudied the species composition, cell density and biomass of phytoplankton desmids collected at six stations in Donghu Lake at intervals of three months monitored from March of 1956 to February of 1957. A total of 122 taxa belonging to 16 genera were identified from qualitative and quantitative samples. Species of Cosmarium were the most popular ones occupy- ing about 41 % of the total species. Based on the observations, the annual mean values of the cell density and biomass were 132.11×102 cells/L and 0.09 mg/L. Cosmarium, Staurastrum, Staurodesmus and Closterium dominated and contributed more than 70 % of the total cell density and biomass at six stations in four seasons. The maximum species number, cell density and biomass in autumn revealed that the highest variety (64 taxa, 1296×102 cells/L and 0.889 mg/L respectively) occurred at Station 3 located in the southern part of Donghu Lake. From then on to the mid 1990s the desmids community decreased sharply in Donghu Lake, resulted clearly from eutrophication in the lake.

Occurrence and Damage Regularity of Spodoptera litura in Broccoli

[Objective] The paper was to explore the occurrence and damage regularity of Spodoptera litura in broccoli,and to reveal the annual movement regularity and seasonal fluctuation regularity of S.litura population.[Method] The monitoring data of sexual attractants at fixed points for 11 consecutive years were summarized and analyzed.[Result] The large occurrence frequency of S.litura in Taizhou was 36.4%;the annual movement showed a downward-opening parabolic form,and the movement trajectory was N =-18.416 t^(2)+182.51 t +179.71,t ={1,2,3,…,n}(n =11;r =0.691 7*).The seasonal fluctuation showed a trend of peak oscillation attenuation curve,and the total moth quantity gradually decreased from sowing to heading stage.The functional model of average daily quantity was m=0.000 2 d^(2)-0.067 5 d+6.797 3,d={1,2,3,…,n}(n =186,r=0.955 2**).Air temperature was the main external factor affecting the seasonal variation of quantity,and there was a significant correlation be-tween the number of ten-day moth trapping quantity and ten-day average temperature:M =0.243 T^(2)-6.935 1 T +46.681(n =108,r =0.560 2**)or M=2.734 4 T-35.446(n=108,r=0.500 3**).Therefore,the moth quantity in the field increased with the increase of ten-day average temperature,and the period from July to September with high temperature and less rainfall was the peak occurrence period of S.litura.[Conclusion] These models can be used to improve the prediction and early warning levels of S.litura in broccoli,and has good guiding significance for decision-making and prevention.

Probability of a zoonotic spillover with seasonal variation

Zoonotic infectious diseases are spread from animals to humans.It is estimated that over 60%of human infectious diseases are zoonotic and 75%of them are emerging zoonoses.The majority of emerging zoonotic infectious diseases are caused by viruses including avian influenza,rabies,Ebola,coronaviruses and hantaviruses.Spillover of infection from animals to humans depends on a complex transmission pathway,which is influenced by epidemiological and environmental processes.In this investigation,the focus is on direct transmission between animals and humans and the effects of seasonal variations on the transmission and recovery rates.Fluctuations in transmission and recovery,besides being influenced by physiological processes and behaviors of pathogen and host,are driven by seasonal variations in temperature,humidity or rainfall.A new time-nonhomogeneous stochastic process is formulated for infectious disease spread from animals to humans when transmission and recovery rates are time-periodic.A branching process approximation is applied near the disease-free state to predict the probability of the first spillover event from animals to humans.This probability is a periodic function of the time when infection is introduced into the animal population.It is shown that the highest risk of a spillover depends on a combination of animal to human transmission,animal to animal transmission and animal recovery.The results are applied to a stochastic model for avian influenza with spillover from domestic poultry to humans.

CHAOS ANALYSIS AND CONTROL FOR A CLASS OF SIR EPIDEMIC MODEL WITH SEASONAL FLUCTUATION

In this paper, the problems of chaos and chaos control for a class of susceptible-infected- removed （SIR） epidemic model with seasonal fluctuation are investigated. The season- ality in outbreak is natural among infectious diseases, as the common influenza, A type H1N1 influenza and so on. It is shown that there exist chaotic phenomena in the epidemic model. Furthermore, the tracking control method is used to control chaotic motions in the epidemic model. A feedback controller is designed to achieve tracking of an ideal out- put. Thus, the density of infected individuals can converge to zero, in other words, thedisease can be disappeared. Finally, numerical simulations illustrate that the controller is effective.

Study of Influence of Terrain and Climatic Factors on Groundwater-Level Fluctuation in a Minor River Basin Using GIS

Terrain environment parameters play a vital role in controlling groundwater movement:its recharge and discharge me-chanisms.Many earlier studies have been conducted relating terrain parameters and groundwater condition using conventional me-thods and remote sensing techniques.This study,however,endeavors to spatially visualize the degree of fluctuation in the ground-water level of Ongur,a minor river basin in different terrain units under different seasons(monsoon and summer) for three histori-cal periods of time using Geographic Information System(GIS) raster analysis.

Non-stationary water-level fluctuation in China＇s Poyang Lake and its interactions with Yangtze River

Seasonal water-level fluctuations （WLF） play a dominate role in lacustrine ecosys- tems. River-lake interaction is a direct factor in changes of seasonal lake WLF, especially for those lakes naturally connected to upstream and downstream rivers. During the past decade, the modification of WLF in the Poyang Lake （the largest freshwater lake in China） has caused intensified flood and irrigation crises, reduced water availability, compromised water quality and extensive degradation of the lake ecosystem. There has been a conjecture as to whether the modification was caused by its interactions with Yangtze River. In this study, we investi- gated the variations of seasonal WLF in China＇s Poyang Lake by comparing the water levels during the four distinct seasons （the dry season, the rising season, the flood season, and the retreating season） before and after 2003 when the Three Gorge Dam operated. The Water Surface Slope （WSS） was used as a representative parameter to measure the changes in river-lake interaction and its impacts on seasonal WLF. The results showed that the magni- tude of seasonal WLF has changed considerably since 2003; the seasonal WLF of the Poy- ang Lake have been significantly altered by the fact that the water levels both rise and retreat earlier in the season and lowered water levels in general. The fluctuations of river-lake in- teractions, in particular the changes during the retreating season, are mainly responsible for these variations in magnitude of seasonal WLF. This study demonstrates that WSS is a rep- resentative parameter to denote river-lake interactions, and the results indicate that more emphasis should be placed on the decrease of the Poyang Lake caused by the lowered water levels of the Yangtze River, especially in the retreating season.

Pollutant removal from municipal wastewater employing baffled subsurface flow and integrated surface flow-floating treatment wetlands

This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units （of the hybrid system） included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses （across the wetland units） illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates （656.0 g COD]（m2.day）） did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots （along with nitrification）, and generation of organic carbon （by the dead macrophytes） to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efflciencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as： substantial input organics loading, hydraulic loading fluctuation, and seasonal variation.