scholarly journals Landscape pattern changes of Carex and its response to water level in Lake Poyang Wetland

2017 ◽  
Vol 29 (4) ◽  
pp. 870-879
Author(s):  
ZHOU Yunkai ◽  
◽  
BAI Xiuling ◽  
NING Lixin
Keyword(s):  
Water Level ◽  
Landscape Pattern ◽  
Lake Poyang ◽  
Response To Water

scholarly journals RESERVOIR COAST RESPONSE TO WATER LEVEL FLUCTUATIONS

2015 ◽  
pp. 61
Author(s):  
A. Sh. Khabidov ◽  
K. V. Marusin ◽  
L. A. Zhindarev ◽  
E. A. Fedorova ◽  
E. A. Sviridova
Keyword(s):  
Water Level ◽  
Water Level Fluctuations ◽  
Response To Water

The initiation of diving apnoea in the frog, Rana pipiens

1976 ◽  
Vol 64 (1) ◽  
pp. 25-38
Author(s):  
N. H. West ◽  
D. R. Jones
Keyword(s):  
Electrical Stimulation ◽  
Water Level ◽  
Rana Pipiens ◽  
Buccal Cavity ◽  
Respiratory Muscles ◽  
Normal Pattern ◽  
Water Head ◽  
Response To Water ◽  
Water Meniscus ◽  
Stimulation Of

1. Diving apnoea in Rana pipiens was initiated by submerging the external nares. As the water level was raised above the frog, both buccal and lung pressure increased by an amount corresponding to the water head. During submergence the external nares remained closed, although the apnoeic period was punctuated by ventilation movements which moved gas between the lungs and buccal cavity. 2. Bilateral section of the ophthalmic nerves did not alter the normal pattern of ventilation in air, although it often resulted in the intake of water into the buccal cavity on submergence. Introduction of water into the buccal cavity, either naturally as in denervates or by injection through a catheter in intact frogs, triggered sustained electromyographical activity in some respiratory muscles. 3. Electroneurograms recorded from the cut peripheral end of an ophthalmic nerve showed that receptors in the external narial region were stimulated by movement of a water meniscus across them. Activity could also be recorded in the ophthalmic nerve in response to water flow past the submerged nares. Punctate stimulation of the narial region confirmed that these receptors were mechanosensitive. 4. Bilateral electrical stimulation of the central ends of cut ophthalmic nerves in lightly anaesthetized frogs caused apnoea with a latency of less than 200 ms. The external nares remained closed throughout the period of stimulation although buccal pressure events, resembling underwater ventilation movements, occurred when stimulation was prolonged.

scholarly journals Influence of water level fluctuation on the mortality and aboveground biomass of the aquatic macrophyte Eleocharis interstincta (VAHL) roemer et schults

2004 ◽  
Vol 47 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Anderson Medeiros dos Santos ◽  
Francisco de Assis Esteves
Keyword(s):  
Water Level ◽  
Aboveground Biomass ◽  
Aquatic Macrophyte ◽  
Sampling Period ◽  
Water Level Fluctuations ◽  
Northern Coast ◽  
Significant Difference ◽  
Influence Of Water ◽  
Response To Water

The goal of this study was to study the biometric alterations of Eleocharis interstincta in response to water level fluctuations in Cabiúnas Lagoon, located on the northern coast of the state of Rio de Janeiro, in the municipality of Macaé. Three quadrats of 0.0625 m² were harvested every two weeks from June/1997 to June/1998; samples were separated into stems, dead stems (detritus) and rhizome; lenghted, dried and weighted. The water level fluctuated seasonally in the macrophyte stand with two periods of drawdown. The first period occurred naturally at the end of winter and beginning of spring, when rainfall in the area was normally lowest. The second period of drawdown was the result of an artificial breaching of the sandbar that isolate the lagoon from the sea. The breach was made in the summer, at the time of highest rainfall, when the water level in the lagoon reached the maximum value recorded during the study (1.35 m). There was a strongly positive correlation of the water level with stems mean height and aboveground biomass, indicating that water level played an important role in the determination of these parameters. There was a significant difference between stem height (ANOVA; p < 0.001) and biomass (ANOVA; p < 0.001) in each sampling period, ranging from 143.9 cm and 338.8 g dry wt.m-2, before the sandbar opening, to 16.3 cm and 20.2 g dry wt.m-2 respectively after the sandbar breaching. The drastic variation of the water level, leading mass mortality of the stems, together with the lowest mean biomass/stem (0.057 g dry wt.individual-1), recorded after the sandbar breaching, did not represent a strong disturbance for E. interstincta, since the resilience time estimated for this population was about 30 days.

scholarly journals Modelling the Impacts of Bathymetric Changes on Water Level in China’s Largest Freshwater Lake

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1469 ◽  
Author(s):  
Lingyan Qi ◽  
Jiacong Huang ◽  
Junfeng Gao ◽  
Zhen Cui
Keyword(s):  
Water Level ◽  
Water Resource Management ◽  
Freshwater Lake ◽  
Lake Ecosystem ◽  
Spatial Gradient ◽  
Dramatic Decline ◽  
Hydrodynamic Processes ◽  
Lake Poyang ◽  
The Stability ◽  
Bathymetric Changes

A recent dramatic decline in water level during the dry season in China’s largest freshwater lake (Lake Poyang) significantly influenced water availability and biogeochemical processes. To learn the potential causes of water level decline, this study investigated the hydrodynamic response to bathymetric changes during three typical hydrological years by scenario simulation using Environmental Fluid Dynamics Code (EFDC). The simulation results indicated that bathymetric changes resulted in a water level decrease during a low water level period. Inter-annual variation in the decrease rate implied that water level in typical dry and wet years were influenced more significantly than that in moderate hydrological years. A spatial gradient in the distribution of water level changes was also observed, which was mainly concentrated in the main channel. Water velocities also slowed down, weakly corresponding to the decrease in water level during the low water level period. Overall, bathymetric changes caused by sand mining contributed to water level and velocity variations, influencing the stability and sustainability of the lake ecosystem. This study can potentially enhance our understanding of the hydrodynamic processes in Lake Poyang and support water resource management.

scholarly journals Integrated biomarker responses of the submerged macrophyte Vallisneria spiralis via hydrological processes from Lake Poyang, China

2018 ◽  
Vol 5 (12) ◽  
pp. 180729 ◽  
Author(s):  
Yong Ji ◽  
Zhidong Yao ◽  
Jie Zhang ◽  
Xueru Wang ◽  
Jixiang Luo ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Light Intensity ◽  
Water Level ◽  
Antioxidant Enzyme ◽  
Enzyme Activities ◽  
Antioxidant Enzyme Activity ◽  
Water Levels ◽  
Antioxidant Enzyme Activities ◽  
Wetland Plant ◽  
Lake Poyang

Vallisneria spiralis , a widely distributed wetland plant, was used to reveal how the light intensity at the top of the plant, plant morphology and antioxidant enzyme activity respond to different hydrologic conditions from Lake Poyang, China. By designing a laboratory experiment simulating historical water levels of low, normal and high wetland plant submersion, this study aimed to elucidate the effects of different levels of flooding on growth and antioxidant enzyme activity for V. spiralis . The results showed that the plant crown light intensity of the treated group and control group (CG) first decreased and then increased along with the seasonal variation of the water level. The maximum and minimum values of the plant crown light intensity were observed in April and July, respectively. Similar to the CG, V. spiralis from the normal and low water level (LWL) groups was measured and had higher plant height growth in the flooding period from May to June, and the entire plant biomass also showed a steady growth trend in the same period. However, the plant growth of the high water level (HWL) group was lower during the whole simulation period, with negative growth in July. Antioxidant enzyme activities changed with the seasonal temperature, and the activity of the CG showed a rising trend. Compared with those of the CG, the antioxidant enzyme activities of the HWL group showed a ‘bell shaped’ trend, which was first significantly induced and then significantly inhibited. In addition, the peroxidase (POD) and catalase (CAT) activities from the LWL group in April were also significantly induced. The integrated biomarker response (IBR) index showed that a comprehensive biological index could well reflect the effects of seasonal water levels in Poyang Lake on the growth of the wetland plant V. spiralis . This study indicated that high flooding levels had the strongest negative effect on the growth and enzyme activity of the submerged plant V. spiralis .

Estimation of ecological water requirements based on habitat response to water level in Huanghe River Delta, China

2010 ◽  
Vol 20 (4) ◽  
pp. 318-329 ◽  
Author(s):  
Baoshan Cui ◽  
Yanyan Hua ◽  
Chongfang Wang ◽  
Xiaolin Liao ◽  
Xuejie Tan ◽  
...  
Keyword(s):  
Water Level ◽  
River Delta ◽  
Water Requirements ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
Response To Water ◽  
Ecological Water Requirements ◽  
Habitat Response
Sign in / Sign up

Export Citation Format

Share Document