Vertical Boundary Mixing Events during Stratification Govern Heat and Nutrient Dynamics in Windy Tropical Lakes with High Water-Level Fluctuations: A Long-Term (2001-2018) Study

Physical processes play important roles in controlling eutrophication and oligotrophication. In stratified lakes, internal waves can cause vertical transport of heat and nutrients without breaking the stratification, through boundary mixing events. Such is the case in tropical Valle de Bravo (VB) lake, where strong diurnal winds drive internal waves, boundary mixing and hypolimnetic warming during stratification periods. We monitored VB during 18 years (2001-2018) when important water-level fluctuations (WLF) occurred, affecting mixing and nutrient flux. Mean hypolimnetic temperature increase (0.06–1.04°C month-1) occurred in all the stratifications monitored. We analyzed temperature distributions and modeled the hypolimnion heat budget to assess vertical mixing between layers (26,618–140,526 m-3h-1), vertical diffusivity coefficient KZ (6.2x10-7–3.3x10-6 m2s-1) and vertical nutrient entrainment to epilimnion on monthly scale. Stability also varied as a function of WLF. Nutrient flux to the epilimnion ranged 0.36–5.99 mg m-2d-1 for soluble reactive phosphorus (SRP) and 5.8–97.1 mg m-2d-1 for dissolved inorganic nitrogen (DIN). During low water-level years, vertical nutrient fluxes increase and can account for up to &gt;40% of the total external nutrients load to the lake. Vertical mixing changes related to WLF affect nutrient recycling, their flux to sediments, ecosystemic metabolic balance and planktonic composition of VB.

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Vertical Boundary Mixing Events during Stratification Govern Heat and Nutrient Dynamics in Windy Tropical Lakes with High Water-Level Fluctuations: A Long-Term (2001-2018) Study

10.20944/preprints202105.0721.v2 ◽

2021 ◽

Author(s):

Martín Merino Ibarra ◽

Jorge A. Ramírez-Zierold ◽

Patricia M. Valdespino-Castillo ◽

Fermin S. Castillo-Sandoval ◽

Andrea P. Guzmán-Arias ◽

...

Keyword(s):

Water Level ◽

Internal Waves ◽

Nutrient Dynamics ◽

Inorganic Nitrogen ◽

Vertical Mixing ◽

Nutrient Flux ◽

Water Level Fluctuations ◽

Diffusivity Coefficient ◽

Boundary Mixing ◽

Stratified Lakes

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Vertical Boundary Mixing Events during Stratification Govern Heat and Nutrient Dynamics in a Windy Tropical Reservoir Lake with Important Water-Level Fluctuations: A Long-Term (2001–2021) Study

Water ◽

10.3390/w13213011 ◽

2021 ◽

Vol 13 (21) ◽

pp. 3011

Author(s):

Martín Merino-Ibarra ◽

Jorge A. Ramírez-Zierold ◽

Patricia M. Valdespino-Castillo ◽

Fermin S. Castillo-Sandoval ◽

Andrea P. Guzmán-Arias ◽

...

Keyword(s):

Water Level ◽

Internal Waves ◽

Nutrient Dynamics ◽

Inorganic Nitrogen ◽

Vertical Mixing ◽

Nutrient Flux ◽

Water Level Fluctuations ◽

Diffusivity Coefficient ◽

Boundary Mixing ◽

Stratified Lakes

Physical processes play important roles in controlling eutrophication and oligotrophication. In stratified lakes, internal waves can cause vertical transport of heat and nutrients without breaking the stratification, through boundary mixing events. Such is the case in tropical Valle de Bravo (VB) reservoir lake, where strong diurnal winds drive internal waves, boundary mixing, and hypolimnetic warming during stratification periods. We monitored VB during 21 years (2001–2021) when important water-level fluctuations occurred, affecting mixing and nutrient flux. Stability also varied as a function of water level. Hypolimnetic warming (0.009–0.028 °C day−1) occurred in all the stratifications monitored. We analyzed temperature distributions and modeled the hypolimnion heat budget to assess vertical mixing between layers (0.639–3.515 × 10−6 m3 day−1), vertical diffusivity coefficient KZ (2.5 × 10−6–13.6 × 10−6 m2 s−1), and vertical nutrient transport to the epilimnion. Nutrient flux from the metalimnion to the epilimnion ranged 0.42–5.99 mg P m−2day−1 for soluble reactive phosphorus (SRP) and 5.8–101.7 mg N m−2day−1 for dissolved inorganic nitrogen (DIN). Vertical mixing and the associated nutrient fluxes increase evidently as the water level decreases 8 m below capacity, and they can increase up to fivefold if the water level drops over 12 m. The observed changes related to water level affect nutrient recycling, ecosystemic metabolic balance, and planktonic composition of VB.

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Vertical Boundary Mixing Events during Stratification Govern Heat and Nutrient Dynamics in Windy Tropical Lakes with High Water-Level Fluctuations: A Long-Term (2001-2018) Study

10.20944/preprints202105.0721.v1 ◽

2021 ◽

Author(s):

Martín Merino-Ibarra ◽

Jorge A. Ramírez-Zierold ◽

Patricia M. Valdespino-Castillo ◽

Fermin Sergio Castillo-Sandoval ◽

Andrea P. Guzmán-Arias ◽

...

Keyword(s):

Water Level ◽

Nutrient Dynamics ◽

Heat Budget ◽

Inorganic Nitrogen ◽

Vertical Mixing ◽

Nutrient Flux ◽

Water Level Fluctuations ◽

Diffusivity Coefficient ◽

Boundary Mixing ◽

Stratified Lakes

Physical processes play important roles in controlling eutrophication and oligotrophication. In stratified lakes, internal waves (IW) can cause vertical transport of heat and nutrients without breaking the stratification, through boundary mixing (BM) events. Such is the case in tropical Valle de Bravo (VB) lake, where strong diurnal winds drive IW, BM and hypolimnetic warming during stratification periods. We monitored VB during 18 years (2001-2018) when important water-level fluctuations (WLF) occurred, affecting mixing and nutrient flux. Mean hypolimnetic temperature increase (0.06–1.04°C month-1) occurred in all the stratifications monitored. We analyzed temperature distributions and modeled the hypolimnion heat budget to assess vertical mixing between layers (26,618–140,526 m-3h-1), vertical diffusivity coefficient KZ (6.2x10-7–3.3x10-6 m2s-1) and vertical nutrient entrainment to epilimnion on monthly scale. Stability also varied as a function of WLF. Nutrient flux to the epilimnion ranged 0.36–5.99 mg m-2d-1 for soluble reactive phosphorus (SRP) and 5.8–97.1 mg m-2d-1 for dissolved inorganic nitrogen (DIN). During low water-level years, vertical nutrient fluxes increase and can account for up to &gt;40% of the total external nutrients load to the lake. Vertical mixing changes with WLF affect nutrient recycling, their flux to sediments, metabolic balance and planktonic composition of VB.

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Estimation of the eddy diffusivity coefficient in a warm monomictic tropical Lake

Journal of Limnology ◽

10.4081/jlimnol.2016.1431 ◽

2016 ◽

Vol 75 (s1) ◽

Cited By ~ 3

Author(s):

David A. Salas de León ◽

Javier Alcocer ◽

Vilma Ardiles Gloria ◽

Benjamín Quiroz-Martínez

Keyword(s):

Temporal Variation ◽

Vertical Mixing ◽

Vertical Component ◽

Eddy Diffusivity ◽

Spatial And Temporal Variation ◽

Tropical Region ◽

Diffusivity Coefficient ◽

Stratified Lakes ◽

Lake Alchichica ◽

Temperature Equation

We used a two-year dataset (1998-1999) of monthly temperature profiles from Lake Alchichica, Mexico to estimate values of the vertical coefficient of eddy diffusivity. This lake is located in a tropical region at high altitude and shows considerable seasonal variations (i.e., rainy and dry seasons). It has an area of 2.3 km2 and a mean depth of 40.9 m. Alchichica is a warm monomictic lake, which annually becomes isothermal near the end of December or early January at the onset of the dry season and remains stratified for the rest of the year (from late March or early April to early December) during the warm-rainy season. Mathematical models of the spatial and temporal variation of passive substances in lakes and oceans require a quantitative formulation of the vertical transport. Vertical mixing is generally a function of the density profile, which, in lakes, can be directly related to the temperature profile. A widely used method to estimate the vertical diffusion coefficients in lakes from temperature data is the flux-gradient method. In the present study, we applied a simple approach to calculate the eddy diffusivity coefficient (Kz) based on the solution of the vertical component of the modeled temperature equation. We characterized the eddy diffusivity coefficient (Kz) in Lake Alchichica as a dynamic coefficient that changes during the year, between years, and with depth, ranging from 10-10 to 10-6 m2 s-1, whereas typical values of Kz in thermally stratified lakes range from 10-9 to 10-2 m2 s-1. As expected, we found the lowest values in the deeper regions of the lake, and that the temporal variation of temperature with depth showed a quasi-bimodal shape from one year to the next. We also found a structure of alternating peaks and troughs in the vertical Kz, which indicates a response to oscillating vertical mixing. We concluded that the solution of the vertical component of the temperature equation could be a useful tool to estimate the eddy diffusivity in lakes. The major advantage of this method is its simplicity. We also conclude that the differences observed in the estimations of eddy diffusivity coefficients in other lakes are attributable to the differences in local characteristics of the thermal conditions in each lake.

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Temperature Trend Analysis in Urmia Lake Basin Compared with Water Level Fluctuations of the Lake

International Institute of Chemical, Biological & Environmental Engineering June 5-6, 2015 Istanbul (Turkey) ◽

10.15242/iicbe.c0615010 ◽

2015 ◽

Keyword(s):

Water Level ◽

Trend Analysis ◽

Temperature Trend ◽

Urmia Lake ◽

Water Level Fluctuations ◽

Lake Basin ◽

Urmia Lake Basin

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AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

International Conference on Technics Technologies and Education ◽

10.15547/ictte.2019.02.041 ◽

2019 ◽

pp. 95-103

Author(s):

Krum Videnov ◽

Vanya Stoykova

Keyword(s):

Water Level ◽

Real Time ◽

Early Warning ◽

Water Sources ◽

Water Levels ◽

Water Level Fluctuations ◽

Level Monitoring ◽

Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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