The formation of a metalimnetic oxygen minimum exemplifies how ecosystem dynamics shape biogeochemical processes: A modelling study

2020 ◽  
Author(s):  
Chenxi Mi ◽  
Tom Shatwell ◽  
Karsten Rinke
Keyword(s):  
Water Quality ◽  
Oxygen Consumption ◽  
Water Temperature ◽  
Community Dynamics ◽  
Decisive Role ◽  
Ecosystem Dynamics ◽  
Algal Community ◽  
Quality Model ◽  
Consumption Rates ◽  
Oxygen Minimum

<p>Metalimnetic oxygen minima are observed in many lakes and reservoirs, but the mechanisms behind this phenomenon are not well understood. Thus, we simulated the metalimnetic oxygen minimum (MOM) in the Rappbode Reservoir (Germany) with a well-established two-dimensional water quality model (CE-QUAL-W2) to systematically quantify the chain of events leading to its formation. We used high-resolution measured data to calibrate the model, which accurately reproduced the physical (e.g. water level and water temperature), biogeochemical (e.g. nutrient and oxygen dynamics) and ecological (e.g. algal community dynamics) features of the reservoir, particularly the spatial and temporal extent of the MOM. The results indicated that around 60% of the total oxygen consumption rate in the MOM layer originated from benthic processes whereas the remainder originated from pelagic processes. The occurrence of the cyanobacterium Planktothrix rubescens in the metalimnion delayed and slightly weakened the MOM through photosynthesis, although its decaying biomass ultimately induced the MOM. Our research also confirmed the decisive role of water temperature in the formation of the MOM since the water temperatures, and thus benthic and pelagic oxygen consumption rates, were higher in the metalimnion than in the hypolimnion. Our model is not only providing novel conclusions about the drivers of MOM development and their quantitative contributions, it is also a new tool for understanding and predicting ecological and biogeochemical water quality dynamics.</p>

scholarly journals Relative Performance of 1-D Versus 3-D Hydrodynamic, Water-Quality Models for Predicting Water Temperature and Oxygen in a Shallow, Eutrophic, Managed Reservoir

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 88
Author(s):  
Xiamei Man ◽  
Chengwang Lei ◽  
Cayelan C. Carey ◽  
John C. Little
Keyword(s):  
Water Quality ◽  
Water Temperature ◽  
Water Quality Model ◽  
Relative Performance ◽  
Bubble Plume ◽  
Quality Model ◽  
Quality Models ◽  
Management Interventions ◽  
Water Quality Models ◽  
D Model

Many researchers use one-dimensional (1-D) and three-dimensional (3-D) coupled hydrodynamic and water-quality models to simulate water quality dynamics, but direct comparison of their relative performance is rare. Such comparisons may quantify their relative advantages, which can inform best practices. In this study, we compare two 1-year simulations in a shallow, eutrophic, managed reservoir using a community-developed 1-D model and a 3-D model coupled with the same water-quality model library based on multiple evaluation criteria. In addition, a verified bubble plume model is coupled with the 1-D and 3-D models to simulate the water temperature in four epilimnion mixing periods to further quantify the relative performance of the 1-D and 3-D models. Based on the present investigation, adopting a 1-D water-quality model to calibrate a 3-D model is time-efficient and can produce reasonable results; 3-D models are recommended for simulating thermal stratification and management interventions, whereas 1-D models may be more appropriate for simpler model setups, especially if field data needed for 3-D modeling are lacking.

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.

Thermal stratification of Portuguese reservoirs: potential impact of extreme climate scenarios

2015 ◽  
Vol 6 (3) ◽  
pp. 544-560 ◽  
Author(s):  
Manuel C. Almeida ◽  
Pedro S. Coelho ◽  
António C. Rodrigues ◽  
Paulo A. Diogo ◽  
Rita Maurício ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Temperature ◽  
Thermal Stratification ◽  
Climate Models ◽  
Climate Impacts ◽  
Water Volume ◽  
Quality Model ◽  
Runoff Reduction ◽  
The Mean ◽  
Water Uses

Changes in water temperature and stratification dynamics can have a significant effect on hydrodynamics and water quality in reservoirs. Therefore, to assess future climate impacts, projections of three regional climate models for Europe, under the IPCC A1B emission scenario (2081–2100), were used with the CE-QUAL-W2 water quality model to evaluate changes in the thermal regime of 24 Portuguese reservoirs, representing different geographic regions, morphologies, volumes and hydrological regimes. Simulation results were compared with reference simulations for the period 1989–2008 and changes in water temperature and thermal stratification characteristics were evaluated. Future inflow scenarios were estimated from precipitation-runoff non-linear correlations and outflows were estimated considering present water uses, including hydropower, water supply and irrigation. Results suggest a significant increment in the mean water temperature of the reservoirs for the entire water volume and at water surface of 2.3 and 2.5 °C, respectively, associated with a runoff reduction of approximately 23%. Overall, variations in annual stratification patterns are characterized by changes in the mean annual length of stratification anomaly that ranged from −21 to +39 days. Results also show the influence of depth and volume over the reservoir's temperature anomaly, highlighting the importance of future water uses and operation rule curves optimization for reservoirs.

scholarly journals CE-QUAL-W2 model of dam outflow elevation impact on temperature, dissolved oxygen and nutrients in a reservoir

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Karl-Erich Lindenschmidt ◽  
Meghan K. Carr ◽  
Amir Sadeghian ◽  
Luis Morales-Marin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Nutrient Dynamics ◽  
Water Withdrawal ◽  
Quality Model ◽  
Temperature Regimes ◽  
Labile Phosphorus ◽  
Daily Water ◽  
Animal Consumption

AbstractDams are typically designed to serve as flood protection, provide water for irrigation, human and animal consumption, and harness hydropower. Despite these benefits, dam operations can have adverse effects on in-reservoir and downstream water temperature regimes, biogeochemical cycling and aquatic ecosystems. We present a water quality dataset of water withdrawal scenarios generated after implementing the 2D hydrodynamic and water quality model, CE-QUAL-W2. The scenarios explore how six water extraction scenarios, starting at 5 m above the reservoir bottom at the dam and increasing upward at 10 m intervals to 55 m, influence water quality in Lake Diefenbaker reservoir, Saskatchewan, Canada. The model simulates daily water temperature, dissolved oxygen, total phosphorus, phosphate as phosphorus, labile phosphorus, total nitrogen, nitrate as nitrogen, labile nitrogen, and ammonium at 87 horizontal segments and at 60 water depths during the 2011–2013 period. This dataset intends to facilitate a broader investigation of in-reservoir nutrient dynamics under dam operations, and to extend the understanding of reservoir nutrient dynamics globally.

Establishment of the Lakes and Reservoirs’ Model

2012 ◽  
Vol 610-613 ◽  
pp. 1962-1966
Author(s):  
Xing Guan Ma ◽  
Jun Ping Sun ◽  
Zhe Pei ◽  
Yu Nan Gao ◽  
Jing Tang ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Temperature ◽  
Simulation Method ◽  
Quality Parameters ◽  
Ecosystem Dynamics ◽  
Model Classification ◽  
Lakes And Reservoirs ◽  
Basic Equations ◽  
The Relationship

This article describes the simulation method of water temperature and the model classification of water quality in lakes and reservoirs, and classic model of ecosystem dynamics of lakes and reservoirs - BA model from the water quality parameters of the relationship between two aspects of the basic equations are introduced. On this basis, establish the eutrophication of ecological models of lakes and reservoirs.

scholarly journals Substantial oxygen consumption by aerobic nitrite oxidation in oceanic oxygen minimum zones

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. M. Beman ◽  
S. M. Vargas ◽  
J. M. Wilson ◽  
E. Perez-Coronel ◽  
J. S. Karolewski ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Nitrate Reduction ◽  
Oxygen Affinity ◽  
Nitrite Oxidation ◽  
Oxygen Minimum Zones ◽  
Oxidation Rates ◽  
Consumption Rates ◽  
High Oxygen Affinity ◽  
Omic Data ◽  
Oxygen Minimum

AbstractOceanic oxygen minimum zones (OMZs) are globally significant sites of biogeochemical cycling where microorganisms deplete dissolved oxygen (DO) to concentrations <20 µM. Amid intense competition for DO in these metabolically challenging environments, aerobic nitrite oxidation may consume significant amounts of DO and help maintain low DO concentrations, but this remains unquantified. Using parallel measurements of oxygen consumption rates and 15N-nitrite oxidation rates applied to both water column profiles and oxygen manipulation experiments, we show that the contribution of nitrite oxidation to overall DO consumption systematically increases as DO declines below 2 µM. Nitrite oxidation can account for all DO consumption only under DO concentrations <393 nM found in and below the secondary chlorophyll maximum. These patterns are consistent across sampling stations and experiments, reflecting coupling between nitrate reduction and nitrite-oxidizing Nitrospina with high oxygen affinity (based on isotopic and omic data). Collectively our results demonstrate that nitrite oxidation plays a pivotal role in the maintenance and biogeochemical dynamics of OMZs.

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