Adaptation of submerged macrophytes to both water depth and flood intensity as revealed by their mechanical resistance

Hydrobiologia ◽  
2012 ◽  
Vol 696 (1) ◽  
pp. 77-93 ◽  
Author(s):  
Guorong Zhu ◽  
Wei Li ◽  
Meng Zhang ◽  
Leyi Ni ◽  
Shengrui Wang
Keyword(s):  
Water Depth ◽  
Submerged Macrophytes ◽  
Mechanical Resistance ◽  
Flood Intensity

scholarly journals Effects of Water Depth on the Growth of the Submerged Macrophytes Vallisneria natans and Hydrilla verticillata: Implications for Water Level Management

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2590
Author(s):  
Qisheng Li ◽  
Yanqing Han ◽  
Kunquan Chen ◽  
Xiaolong Huang ◽  
Kuanyi Li ◽  
...  
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Deep Water ◽  
Submerged Macrophytes ◽  
Hydrilla Verticillata ◽  
Water Level Fluctuations ◽  
Total Biomass ◽  
Intermediate Water ◽  
Factors Affecting ◽  
Vallisneria Natans

Water level is one of the most important factors affecting the growth of submerged macrophytes in aquatic ecosystems. The rosette plant Vallisneria natans and the erect plant Hydrilla verticillata are two common submerged macrophytes in lakes of the middle and lower reaches of the Yangtze River, China. How water level fluctuations affect their growth and competition is still unknown. In this study, three water depths (50 cm, 150 cm, and 250 cm) were established to explore the responses in growth and competitive patterns of the two plant species to water depth under mixed planting conditions. The results show that, compared with shallow water conditions (50 cm), the growth of both submerged macrophytes was severely suppressed in deep water depth (250 cm), while only V. natans was inhibited under intermediate water depth (150 cm). Moreover, the ratio of biomass of V. natans to H. verticillata gradually increased with increasing water depth, indicating that deep water enhanced the competitive advantage of V. natans over H.verticillata. Morphological adaptation of the two submerged macrophytes to water depth was different. With increasing water depth, H. verticillata increased its height, at the cost of reduced plant numbers to adapt to poor light conditions. A similar strategy was also observed in V. natans, when water depth increased from 50 cm to 150 cm. However, both the plant height and number were reduced at deep water depth (250 cm). Our study suggests that water level reduction in lake restoration efforts could increase the total biomass of submerged macrophytes, but the domination of key plants, such as V. natans, may decrease.

scholarly journals Effects of water depth on growth of submerged macrophytes Vallisneria natans and Myriophyllum spicatum

2019 ◽  
Vol 31 (4) ◽  
pp. 1045-1054
Author(s):  
LI Qisheng ◽  
◽  
HUANG Qiang ◽  
LI Yongji ◽  
HAN Yanqing ◽  
...  
Keyword(s):  
Water Depth ◽  
Submerged Macrophytes ◽  
Myriophyllum Spicatum ◽  
Vallisneria Natans

scholarly journals Effects of Water Level Fluctuations on the Growth Characteristics and Community Succession of Submerged Macrophytes: A Case Study of Yilong Lake, China

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2900
Author(s):  
Fengbin Zhao ◽  
Xin Fang ◽  
Zeyu Zhao ◽  
Xiaoli Chai
Keyword(s):  
Community Structure ◽  
Water Level ◽  
Water Depth ◽  
Seed Bank ◽  
Submerged Macrophytes ◽  
Growth Characteristics ◽  
Community Succession ◽  
Submerged Plant ◽  
Submerged Plants ◽  
Emergent Plants

Water level fluctuation (WLF) has a significant effect on aquatic macrophytes, but few experimental studies have examined the effect of WLF on submerged community succession, especially from a large-scale perspective. In this study, field monitoring of WLF and submerged macrophytes was conducted in Yilong Lake (SE China) over two years, and the impacts of WLF on the growth characteristics and the community structure of submerged macrophytes were determined. The results show that the biomass of submerged macrophytes decreased significantly after the water level increased and submerged macrophytes could cope with the adverse environment by adjusting their growth posture, for example, increasing plant length and reducing branch number. However, different submerged plants have different regulatory abilities, which leads to a change in the community structure. Myriophyllum spicatum, Stuckenia pectinata, and Najas marina had better adaptation abilities to WLF than Najas minor and Utricularia vulgaris. Changes in water depth, dissolved oxygen, and transparency significantly contribute to the effect of WLF on submerged plant communities. Therefore, when determining the range of WLF, the above three critical factors and submerged plant species should be considered. WLF changed the spatial distribution of the aquatic plant community. When water levels rose, the density of the submerged macrophyte community in the original growth region reduced as the emergent plants migrated to shallower water, and the seed bank germination was aided by transparent water produced among emergent plants. This can be used as a pioneering measure to restore submerged plants in eutrophic lakes with low transparency. In addition, a suitable water depth created by WLF was conducive to activating the seed bank and improving the diversity of aquatic plants. Finally, a distribution map of aquatic plants in Yilong Lake is drawn.

scholarly journals The effects of water depth on the growth of two submerged macrophytes in an in situ experiment

2021 ◽  
Vol 36 (1) ◽  
pp. 271-284
Author(s):  
Xiaodong Wu ◽  
Jizheng Pan ◽  
Weixiang Ren ◽  
Jiuyun Yang ◽  
Lu Luo
Keyword(s):  
Water Depth ◽  
Submerged Macrophytes ◽  
In Situ Experiment

Top-down control in freshwater lakes: the role of nutrient state, submerged macrophytes and water depth

1997 ◽  
pp. 151-164 ◽  
Author(s):  
Erik Jeppesen ◽  
Jens Peder Jensen ◽  
Martin Søndergaard ◽  
Torben Lauridsen ◽  
Leif Junge Pedersen ◽  
...  
Keyword(s):  
Water Depth ◽  
Submerged Macrophytes ◽  
Freshwater Lakes ◽  
Top Down

The limits of human performance

2008 ◽  
Vol 44 ◽  
pp. 11-26 ◽  
Author(s):  
Ralph Beneke ◽  
Dieter Böning
Keyword(s):  
Human Performance ◽  
Safety Margin ◽  
Afferent Input ◽  
Metabolic Energy ◽  
Human Organism ◽  
Mechanical Resistance ◽  
As Doping ◽  
Gene And Protein Expression ◽  
Underlying Mechanisms ◽  
Biochemical Research

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

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