scholarly journals Ecological processes in macrophyte- and phytoplankton-dominated shallow lakes

2006 ◽  
Vol 55 (4) ◽  
pp. 280
Author(s):  
H Agasild ◽  
T Feldmann ◽  
A Järvalt ◽  
H Luup ◽  
P Nõges ◽  
...  
Keyword(s):  
Shallow Lakes ◽  
Ecological Processes

scholarly journals Simulating Diurnal Variations of Water Temperature and Dissolved Oxygen in Shallow Minnesota Lakes

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1980
Author(s):  
Bushra Tasnim ◽  
Jalil A. Jamily ◽  
Xing Fang ◽  
Yangen Zhou ◽  
Joel S. Hayworth
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Shallow Lakes ◽  
Quality Model ◽  
Lake Water Quality ◽  
Ecological Processes ◽  
Turbulent Diffusion Coefficient ◽  
Hourly Data ◽  
Mean Square Errors

In shallow lakes, water quality is mostly affected by weather conditions and some ecological processes which vary throughout the day. To understand and model diurnal-nocturnal variations, a deterministic, one-dimensional hourly lake water quality model MINLAKE2018 was modified from daily MINLAKE2012, and applied to five shallow lakes in Minnesota to simulate water temperature and dissolved oxygen (DO) over multiple years. A maximum diurnal water temperature variation of 11.40 °C and DO variation of 5.63 mg/L were simulated. The root-mean-square errors (RMSEs) of simulated hourly surface temperatures in five lakes range from 1.19 to 1.95 °C when compared with hourly data over 4–8 years. The RMSEs of temperature and DO simulations from MINLAKE2018 decreased by 17.3% and 18.2%, respectively, and Nash-Sutcliffe efficiency increased by 10.3% and 66.7%, respectively; indicating the hourly model performs better in comparison to daily MINLAKE2012. The hourly model uses variable hourly wind speeds to determine the turbulent diffusion coefficient in the epilimnion and produces more hours of temperature and DO stratification including stratification that lasted several hours on some of the days. The hourly model includes direct solar radiation heating to the bottom sediment that decreases magnitude of heat flux from or to the sediment.

Adoption Decision and Sustainable Utilization of Soil Conservation Technologies: Empirical Evidence from North West Ethiopia

2019 ◽  
Vol 10 ◽  
pp. 1853-1863
Author(s):  
Kassaye Gurebiyaw Legese ◽  
Taye Melese ◽  
Tadie Mire ◽  
Abebe Birara ◽  
Kefale Eniyew
Keyword(s):  
Water Conservation ◽  
Soil Conservation ◽  
Sampling Technique ◽  
Household Survey ◽  
Ecological Processes ◽  
Related Factors ◽  
Severe Problem ◽  
North West ◽  
Household Heads ◽  
North Gondar Zone

Soil is a crucial and precious natural resource that govern numerous ecological processes. However, in Ethiopia particularly in north Gondar zone, soil erosion is a severe problem and a major cause of the decline of agricultural productivity. The adoption and diffusion of soil and water conservation practices (SWC), as a way to tackle this challenge, has become an important issue in the development policy agenda in the zone. Therefore, this study was to identify factors affecting Soil conservation investments in the North Gondar zone. Data was collected through interviewed schedule, filed observation and focus group discussion. The multistage sampling technique was employed to select 206 sample households.  Both descriptive and econometrics model was used to analyze the collected data. A multivariate profit (MPV) model was used to analyze the effect of demographic, socioeconomic, market, institutional and biophysical related factors on the interdependent investment decisions of SWC practices using household survey. The MPV model analysis indicates that farmers invest a combination of practices at parcel level by considering substitution and complementarity effects of the practices. The results also revealed that age of household heads, literacy status of household heads, off-farm activity, distance of farmlands from homesteads, tropical livestock unit, and access to training were influence farmers’ investments in SWC practices. The overall results indicate that the identified physical, socioeconomic, and institutional factors influence promote or hinder investments in SWC practice so, policymakers should take into consideration these various factors in designing and implementing SWC policies and Programmers.

1465 - Cell size distribution of planktonic bacteria in shallow lakes

2018 ◽  
Author(s):  
Zsuzsanna Márton ◽  
Bianka Csitári ◽  
Tamas Felfoldi ◽  
Anna J Szekely ◽  
Attila Szabo
Keyword(s):  
Size Distribution ◽  
Cell Size ◽  
Shallow Lakes ◽  
Cell Size Distribution ◽  
Planktonic Bacteria

Energetic Asymmetry Connected with Energy Flow Changes in Response to Eutrophication: A Study of Multiple Fish Species in Subtropical Shallow Lakes

2020 ◽  
Vol 67 (4) ◽  
pp. 305
Author(s):  
Hong Fu ◽  
Huan Zhang ◽  
Liang He ◽  
Yongcui Sha ◽  
Kangshun Zhao ◽  
...  
Keyword(s):  
Fish Species ◽  
Shallow Lakes ◽  
Energy Flow ◽  
Flow Changes

Prominence of environmental and anthropogenic agents on the occurrence of coral reef bleaching syndrome and coral diseases

2024 ◽  
Vol 74 (10) ◽  
pp. 6139-2024
Author(s):  
MICHAŁ SCHULZ ◽  
ALEKSANDRA ŁOŚ ◽  
PATRYCJA SKOWRONEK ◽  
ANETA STRACHECKA
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Oil Spills ◽  
Global Scale ◽  
Ecological Processes ◽  
Coral Diseases ◽  
Rapid Changes ◽  
Anthropogenic Threats ◽  
Negative Factors ◽  
Main Relationship

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.

The lake ecosystem simulation program

1995 ◽  
Vol 31 (8) ◽  
pp. 367-370
Author(s):  
J. Heringa ◽  
H. Hylkema ◽  
M. Kroes ◽  
E. Ludden ◽  
P. G. van Schaick Zillesen
Keyword(s):  
Mathematical Model ◽  
Water Resources ◽  
Computer Program ◽  
Water Resources Management ◽  
Lake Ecosystem ◽  
Original Research ◽  
Ecological Processes ◽  
Resources Management ◽  
Lake Ecology ◽  
Ecosystem Simulation

The computer program LAKE simulates a shallow lake ecosystem. The program is based on a mathematical model. In the model the most important aspects of several models for water resources management are integrated (Collins and Wlosinski, 1988; Jørgensen, 1976; Jørgensen et al., 1978; Scheffer, 1988). Furthermore, the model describes several ecological processes that have not yet been described by lake-ecosystem models so far. In the computer program, the mathematical model and an advanced, object oriented, user interface are combined. Following this approach the use of the original research models was extended to a use for the purpose of teaching lake ecology. We suggest that the same approach may be followed to open research models to other groups concerned with water resources management, such as management authorities, industry, agricultural extension, nature conservation and recreation.

Towards evolutionary agroecology

2018 ◽  
Vol 6 (14) ◽  
pp. 51 ◽  
Author(s):  
Kristin L. Mercer
Keyword(s):  
Social Dynamics ◽  
Agricultural Systems ◽  
Short Term ◽  
Ecological Processes ◽  
Genetic Analyses ◽  
Holistic Perspective ◽  
Evolutionary Study ◽  
Quantitative Genetic ◽  
Field Evolution

Agroecology derives much of its strength from interactions between disciplines that produce a holistic perspective on agricultural systems and issues.  Although ongoing integration of social dynamics into agroecology has strengthened the field, evolution and genetics have not been embraced to the same degree, despite the fact that they have been are discussed in some common agroecology texts.  I argue that the field of agroecology could extend its reach and depth by embracing the evolutionary study of agroecosystems.  Areas of evolutionary inquiry with relevance to agriculture focus on long or short term processes, encompass a range of scales, incorporate molecular or quantitative genetic analyses, and explore ecological processes to differing degrees.

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