Existence of the Optimum in Shallow Lake Type Models with Hysteresis Effect

2021 ◽  
Author(s):  
Francesco Bartaloni
Keyword(s):  
Shallow Lake ◽  
Hysteresis Effect ◽  
Lake Type

About the mechanism of the granite-free zones formation in the Black Sea

2021 ◽  
pp. 28-39
Author(s):  
Nikolay V Esin ◽  
Alexey V. Khortov ◽  
Nikolay I. Esin
Keyword(s):  
Black Sea ◽  
Deep Water ◽  
Shallow Lake ◽  
Earth’S Crust ◽  
The Black Sea ◽  
Earth's Crust ◽  
Academy Of Sciences ◽  
Lake Type ◽  
Rapid Transformation ◽  
Deep Water Basin

One of the important unsolved problems related to the evolution of living conditions on Earth is the mechanism of the rapid transformation of the Black Sea from a shallow lake-type sea into a deep-water basin, the earth's crust in the central part of which does not have a granite layer. There is no explanation as to how “granite-free depressions” were formed at the bottom of the sea, which are currently covered by sediment. Investigations of these processes were started in the middle of the last century by scientists-geologists of the Institute of Oceanology of the Russian Academy of Sciences and its South. In this article, the authors propose a mechanism for the destruction of the earth's crust and the formation of depressions in the inner seas during the Messinian crisis.

Field Observation and Simulation of Sediment Resuspension in a Shallow Lake

1988 ◽  
Vol 20 (6-7) ◽  
pp. 263-270 ◽  
Author(s):  
K. Otsubo ◽  
K. Muraoka
Keyword(s):  
Numerical Simulation ◽  
Shallow Lake ◽  
Water Wave ◽  
Field Data ◽  
Sediment Resuspension ◽  
Field Research ◽  
Lake Kasumigaura ◽  
Bed Erosion ◽  
Current Water ◽  
Good Agreement

The dispersion and resuspension of sediments in Takahamairi Bay basin of Lake Kasumigaura were studied by means of field research and numerical simulation. The field data on wind direction and velocity, lake current, water wave, and turbidity were shown. Based on these results, we discuss how precipitated sediments were resuspended in this shallow lake. To predict the turbidity and the depth of bed erosion, a simulation model was established for this lake. The calculated turbidity showed good agreement with the field data. According to the simulated results, the turbidity reaches 200 ppm, and the bed is eroded several millimeters deep when the wind velocity exceeds 12 m/s in the lake.

Multivariate analysis of long term water quality changes of shallow Lake Balaton

2006 ◽  
Vol 29 (4) ◽  
pp. 2051-2055 ◽  
Author(s):  
G. Kiss ◽  
Gy. Dévai ◽  
B. Tóthmérész ◽  
A. Szabó
Keyword(s):  
Water Quality ◽  
Multivariate Analysis ◽  
Shallow Lake ◽  
Lake Balaton ◽  
Quality Changes

scholarly journals Antecedent lake conditions shape resistance and resilience of a shallow lake ecosystem following extreme wind storms

2021 ◽  
Author(s):  
Michael W. Thayne ◽  
Benjamin M. Kraemer ◽  
Jorrit P. Mesman ◽  
Bastiaan W. Ibelings ◽  
Rita Adrian
Keyword(s):  
Shallow Lake ◽  
Lake Ecosystem ◽  
Extreme Wind ◽  
Wind Storms

scholarly journals Nutrient Loading, Temperature and Heat Wave Effects on Nutrients, Oxygen and Metabolism in Shallow Lake Mesocosms Pre-Adapted for 11 Years

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 127
Author(s):  
Erik Jeppesen ◽  
Joachim Audet ◽  
Thomas A. Davidson ◽  
Érika M. Neif ◽  
Yu Cao ◽  
...  
Keyword(s):  
Heat Wave ◽  
Shallow Lake ◽  
Nutrient Loading ◽  
Global Changes ◽  
Significant Positive Effect ◽  
Mixed Effect ◽  
Chl A ◽  
Nutrient Loadings ◽  
Positive Effect ◽  
Oxygen Concentrations

Global changes (e.g., warming and population growth) affect nutrient loadings and temperatures, but global warming also results in more frequent extreme events, such as heat waves. Using data from the world’s longest-running shallow lake experimental mesocosm facility, we studied the effects of different levels of nutrient loadings combined with varying temperatures, which also included a simulated 1-month summer heat wave (HW), on nutrient and oxygen concentrations, gross ecosystem primary production (GPP), ecosystem respiration (ER), net ecosystem production (NEP) and bacterioplankton production (BACPR). The mesocosms had two nutrient levels (high (HN) and low (LN)) combined with three different temperatures according to the IPCC 2007 warming scenarios (unheated, A2 and A2 + 50%) that were applied for 11 years prior to the present experiment. The simulated HW consisted of 5 °C extra temperature increases only in the A2 and A2 + 50% treatments applied from 1 July to 1 August 2014. Linear mixed effect modeling revealed a strong effect of nutrient treatment on the concentration of chlorophyll a (Chl-a), on various forms of phosphorus and nitrogen as well as on oxygen concentration and oxygen percentage (24 h means). Applying the full dataset, we also found a significant positive effect of nutrient loading on GPP, ER, NEP and BACPR, and of temperature on ER and BACPR. The HW had a significant positive effect on GPP and ER. When dividing the data into LN and HN, temperature also had a significant positive effect on Chl-a in LN and on orthophosphate in HN. Linear mixed models revealed differential effects of nutrients, Chl-a and macrophyte abundance (PVI) on the metabolism variables, with PVI being particularly important in the LN mesocosms. All metabolism variables also responded strongly to a cooling-low irradiance event in the middle of the HW, resulting in a severe drop in oxygen concentrations, not least in the HN heated mesocosms. Our results demonstrate strong effects of nutrients as well as an overall rapid response in oxygen metabolism and BACPR to changes in temperature, including HWs, making them sensitive ecosystem indicators of climate warming.

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