Long-term data show effects of atmospheric temperature anomaly and reservoir size on water temperature, thermal structure, and dissolved oxygen

Abstract On the basis of the results of calibration of current meters at water of varying temperatures, a hypothesis that water temperature influences measured water velocities was formulated. The analysis of our long-term data showed that the water temperature does have an influence on measured water velocity. This influence can be taken into account for practical purposes as a contribution to the uncertainty of measurements. The influence depends on the type of current meter propeller. This paper presents results obtained for the Ott C-2 current meter with propellers of the types 1, 2, 3, 5 and 6. Our analysis showed that the uncertainty is equal or less than 5% for measurements carried out in water with temperatures above 8°C. The differences between measured water velocities for water temperatures 5°C and 20°C reached maximum 6% (depending on the propeller) in a slowly flowing water (rotational frequency n = 1 s-1). For rotational velocity n ≥ 2 s-1 the differences between velocities measured at water temperatures 5 and 20°C were mostly under 3%. The less influenced propeller is of type 3 for which the uncertainty of measurement does not reach 5% even for water temperature 1°C if the rotational frequency is bigger than 0.7 s-1.

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Long‐term forecast of water temperature and dissolved oxygen profiles in deep lakes using artificial neural networks conjugated with wavelet transform

Limnology and Oceanography ◽

10.1002/lno.11390 ◽

2019 ◽

Vol 65 (6) ◽

pp. 1297-1317

Author(s):

Ali Saber ◽

David E. James ◽

Donald F. Hayes

Keyword(s):

Neural Networks ◽

Artificial Neural Networks ◽

Wavelet Transform ◽

Dissolved Oxygen ◽

Water Temperature ◽

Deep Lakes ◽

Term Forecast ◽

Artificial Neural ◽

Oxygen Profiles

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Dissolved oxygen and water temperature dynamics in lowland rivers over various timescales

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2015-0041 ◽

2015 ◽

Vol 63 (4) ◽

pp. 353-363 ◽

Cited By ~ 22

Author(s):

Agnieszka Rajwa-Kuligiewicz ◽

Robert J. Bialik ◽

Paweł M. Rowiński

Keyword(s):

Dissolved Oxygen ◽

Water Temperature ◽

Environmental Variability ◽

Physical Factors ◽

Lowland Rivers ◽

Physical Conditions ◽

The Impact ◽

Floodplain Hydrology ◽

Oxygen Dynamics

Abstract The impact of floodplain hydrology on the in-stream dissolved oxygen dynamics and the relation between dissolved oxygen and water temperature are investigated. This has been done by examining the time series of dissolved oxygen and water temperature coupled with meteorological and hydrological data obtained from two lowland rivers having contrasting hydrological settings. Spectral analysis of long-term oxygen variations in a vegetated river revealed a distinct scaling regime with slope ‘–1’ indicating a self-similar behaviour. Identical slopes were obtained for water temperature and water level. The same power-law behaviour was observed for an unvegetated river at small timescales revealing the underlying scaling behaviour of dissolved oxygen regime for different types of rivers and over various time scales. The results have shown that the oxygenation of a vegetated river is strongly related to its thermal regime and flow conditions. Moreover, analysis of short-term fluctuations in the unvegetated river demonstrated that physical factors such as rainfall and backwaters play a substantial role in the functioning of this ecosystem. Finally, the results show that the relation between water temperature and dissolved oxygen concentration at the diurnal timescale exhibits a looping behaviour on the variable plot. The findings of this study provide an insight into the sensitivity of rivers to changing hydro-physical conditions and can be useful in the assessment of environmental variability.

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Historical modelling of changes in Lake Erken thermal conditions

Hydrology and Earth System Sciences ◽

10.5194/hess-23-5001-2019 ◽

2019 ◽

Vol 23 (12) ◽

pp. 5001-5016 ◽

Cited By ~ 5

Author(s):

Simone Moras ◽

Ana I. Ayala ◽

Don C. Pierson

Keyword(s):

Water Temperature ◽

Air Temperature ◽

Thermal Stratification ◽

Thermal Structure ◽

Time Step ◽

Entire Interval ◽

Entire Study ◽

Short Period ◽

Study Interval

Abstract. Historical lake water temperature records are a valuable source of information to assess the influence of climate change on lake thermal structure. However, in most cases such records span a short period of time and/or are incomplete, providing a less credible assessment of change. In this study, the hydrodynamic GOTM (General Ocean Turbulence Model, a hydrodynamic model configured in lake mode) was used to reconstruct daily profiles of water temperature in Lake Erken (Sweden) over the period 1961–2017 using seven climatic parameters as forcing data: wind speed (WS), air temperature (Air T), atmospheric pressure (Air P), relative humidity (RH), cloud cover (CC), precipitation (DP), and shortwave radiation (SWR). The model was calibrated against observed water temperature data collected during the study interval, and the calibrated model revealed a good match between modelled and observed temperature (RMSE =1.089 ∘C). From the long-term simulations of water temperature, this study focused on detecting possible trends in water temperature over the entire study interval 1961–2017 and in the sub-intervals 1961–1988 and 1989–2017, since an abrupt change in air temperature was detected in 1988. The analysis of the simulated temperature showed that epilimnetic temperature increased on average by 0.444 and 0.792 ∘C per decade in spring and autumn in the sub-interval 1989–2017. Summer epilimnetic temperature increased by 0.351 ∘C per decade over the entire interval 1961–2017. Hypolimnetic temperature increased significantly in spring over the entire interval 1961–2017, by 0.148 and by 0.816 ∘C per decade in autumn in the sub-interval 1989–2016. Whole-lake temperature showed a significant increasing trend in the sub-interval 1989–2017 during spring (0.404 ∘C per decade) and autumn (0.789 ∘C per decade, interval 1989–2016), while a significant trend was detected in summer over the entire study interval 1961–2017 (0.239 ∘C per decade). Moreover, this study showed that changes in the phenology of thermal stratification have occurred over the 57-year period of study. Since 1961, the stability of stratification (Schmidt stability) has increased by 5.365 J m−2 per decade. The duration of thermal stratification has increased by 7.297 d per decade, corresponding to an earlier onset of stratification of ∼16 d and to a delay of stratification termination of ∼26 d. The average thermocline depth during stratification became shallower by ∼1.345 m, and surface-bottom temperature difference increased over time by 0.249 ∘C per decade. The creation of a daily time step water temperature dataset not only provided evidence of changes in Erken thermal structure over the last decades, but is also a valuable resource of information that can help in future research on the ecology of Lake Erken. The use of readily available meteorological data to reconstruct Lake Erken's past water temperature is shown to be a useful method to evaluate long-term changes in lake thermal structure, and it is a method that can be extended to other lakes.

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Hydrographic maintenance of deep anoxia in a tidally influenced saline lagoon

Marine and Freshwater Research ◽

10.1071/mf17199 ◽

2018 ◽

Vol 69 (3) ◽

pp. 432 ◽

Cited By ~ 4

Author(s):

S. Kelly ◽

E. de Eyto ◽

M. Dillane ◽

R. Poole ◽

G. Brett ◽

...

Keyword(s):

Dissolved Oxygen ◽

Deep Water ◽

Oxygen Depletion ◽

Exchange Flow ◽

Dynamic Events ◽

Basin Scale ◽

Renewal Events ◽

Term Data ◽

Oxygen Concentrations

Low dissolved oxygen concentrations are of increasing concern in aquatic ecosystems, particularly at the interface between freshwater and marine environments. Oxygen depletion occurs naturally in many perennially stratified systems and it remains to be seen how climate change will affect these habitats. This is due, in part, to a lack of high-resolution, long-term data describing interannual variability in dissolved oxygen concentrations within stratified basins. Physicochemical parameters for Lough Furnace, an ecologically important tidal lagoon, were assessed using daily measurements (2009–14) from an undulating CTD (conductivity, temperature and depth) profiler and observations of tidal exchange flow. Continuous vertical saline stratification existed, with anoxia (<0.1mgL–1) typically persisting below 6m. Tidal inflows were generally restricted, with deep-water renewal events by intrusions of denser spring tidal water occurring episodically (three times in 6 years), following prolonged periods of low freshwater input. Although wind forcing alone was not sufficient to generate basin-scale mixing, the conditions that led to deep-water renewals may also be conducive to wind-driven upwelling events in nearshore areas. These findings have wider application to larger-scale two-layered stratified systems with deep anoxia because the ability to forecast such dynamic events is important for assessing the ecological implications of dissolved oxygen depletion.

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Historical modelling of changes in Lake Erken thermal conditions

10.5194/hess-2019-199 ◽

2019 ◽

Author(s):

Simone Moras ◽

Ana I. Ayala ◽

Don C. Pierson

Keyword(s):

Water Temperature ◽

Thermal Stratification ◽

Thermal Structure ◽

Time Step ◽

Entire Interval ◽

Entire Study ◽

Study Interval ◽

Daily Time Step ◽

Daily Time

Abstract. The thermal structure of lakes is strictly related to climate and to the variability of thermal and mixing dynamics. In this study, a physical hydrodynamic model (GOTM) was used to reconstruct daily time-step water temperature of Lake Erken (Sweden) over the period 1961–2017, using seven climatic parameters as forcing data: wind speed (WS), air temperature (Air T), atmospheric pressure (Air P), relative humidity (RH), cloud cover (CC), precipitation (DP) and shortwave radiation (SWR). The model was calibrated against real water temperature data collected during the study interval, and the calibrated model revealed a good match between modelled and observed temperature (RMSE = 1.112 °C). From the long-term simulations of water temperature, this study focused on detecting possible trends in water temperature over the entire study interval 1961–2017 and in the sub-intervals 1961–1987 and 1988–2017. The analysis of the simulated temperature showed that epilimnetic temperature has increased on average by +0.43 °C/decade and +0.809 °C/decade in spring and autumn in the sub-interval 1988–2017. Summer epilimnetic temperature has increased by +0.348 °C/decade over the entire interval 1961–2017. Hypolimnetic temperature has increased significantly in the sub-interval 1988–2016 by +0.827 °C/decade in autumn. Whole-lake temperature showed a significant increasing trend in the sub-interval 1988–2017 during spring (+0.378 °C/decade) and in autumn (+0.809 °C/decade). Moreover, this study showed that changes in the phenology of thermal stratification, have occurred over the 57-years period of study. Since 1961 the stability of stratification (Schmidt Stability) has increased by 5.535 J m−2/decade. The duration of thermal stratification has increased by 7.083 days/decade, correspondent with an earlier onset of stratification of ~ 16 days and to a delay of stratification termination of ~ 26 days. The average thermocline depth during stratification became shallower by ~ 1.242 m, and surface-bottom temperature difference increased over time by +0.249 °C/decade. The creation of daily-time step water temperature dataset not only provided evidence of changes in Erken thermal structure over the last decades, but it is also a valuable resource of information that can help in future research on the ecology of Lake Erken. The use of readily available meteorological data to reconstruct Lake Erken's past water temperature is shown to be a useful method to evaluate long-term changes in lake thermal structure, and it is a method that can be extended to other lakes.

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Dissolved oxygen stratification in a small lake depending on water temperature and density and wind impact

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/937/3/032019 ◽

2021 ◽

Vol 937 (3) ◽

pp. 032019

Author(s):

N Palshin ◽

G Zdorovennova ◽

T Efremova ◽

S Bogdanov ◽

A Terzhevik ◽

...

Keyword(s):

Dissolved Oxygen ◽

Water Temperature ◽

Wind Load ◽

Density Stratification ◽

Wind Regime ◽

Independent Variables ◽

Decomposition Of Organic Matter ◽

Do Concentration ◽

Weak Stratification

Abstract The dissolved oxygen (DO) is one of the most important parameters in lakes ecosystem. Variability of DO in lakes is associated with the absorption of oxygen due to the decomposition of organic matter and chemical reactions and the release of oxygen as a result of photosynthesis. The DO concentration also depends on seasonal changes in water temperature and mixing regime. The aim of this work is to assess the influence of seasonal thermal and density stratification on the DO stratification in a small mesotrophic lake and to develop a regression DO model, with water temperature and density and characteristics of wind regime as independent variables. Long-term measurements of water temperature and DO in small Karelian Lake Vendyurskoe in 2007-2020 were used. At the stage of spring-summer heating, three periods are considered when the water column was in the state of homothermy (May 15-June 15), weak stratification (July 15-August 15), and strong stratification (July 15-August 15). The wind load (number of days with wind speed more than 3 m/s for each period) was analysed based on the weather station Petrozavodsk data. As a result of multiple regression analysis, taking into account the wind load, dependences of DO stratification on water temperature stratification (R2 = 0.51) and water density stratification (R2 = 0.61) are found. Obtained regression DO models can be used for solving various environmental tasks.

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Long-term variability of oceanographic data at the Port Hacking 50-metre station

Marine and Freshwater Research ◽

10.1071/mf9770057 ◽

1977 ◽

Vol 28 (1) ◽

pp. 57 ◽

Cited By ~ 10

Author(s):

SD Hahn ◽

DJ Rochford ◽

JS Godfrey

Keyword(s):

Dissolved Oxygen ◽

Water Temperature ◽

Inorganic Phosphate ◽

Time Interval ◽

Seasonal Cycles ◽

Oceanographic Variables ◽

Oceanographic Data ◽

Annual Means

Measurements of water temperature, salinity, dissolved oxygen, nitrate and inorganic phosphate have been made at the Port Hacking 50-m station which is about 30 km south of Sydney and 5 km offshore. This paper reports an analysis of the data obtained between 1942 and 1972. Mean seasonal cycles of each of these variables have been evaluated for the time interval, as well as the annual means for each year. Shorter period fluctuations are studied by cross correlating the monthly anomalies of the various oceanographic variables.

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Evaluation of oxythermal metrics and benchmarks for the protection of cisco (Coregonus artedi) habitat quality and quantity in Wisconsin lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2017-0043 ◽

2018 ◽

Vol 75 (4) ◽

pp. 600-608 ◽

Cited By ~ 7

Author(s):

John Lyons ◽

Timothy P. Parks ◽

Kristi L. Minahan ◽

Aaron S. Ruesch

Keyword(s):

Dissolved Oxygen ◽

Great Lakes ◽

Water Temperature ◽

Water Column ◽

Laurentian Great Lakes ◽

Great Lakes Region ◽

Wide Range ◽

Coregonus Artedi ◽

Oxygenated Water

The cisco (Coregonus artedi) requires cold, well-oxygenated water and is threatened by climate warming and lake eutrophication, especially at the southern edge of its range in the Laurentian Great Lakes region. In this paper, a method is described to assess the quality, quantity, and variability of suitable cisco habitat. Two metrics are proposed to characterize existing cisco oxythermal habitat in this region: water temperature in the water column at a dissolved oxygen of 6 mg/L (TDO6) and “cisco layer thickness” (CLT), the vertical extent of the water column within which water temperature is ≤22.8 °C and dissolved oxygen is ≥6 mg/L. It is proposed that values of TDO6 = 22.8 °C and CLT = 1 m be used as benchmarks to identify cisco lakes with potentially stressful oxythermal habitat. Long-term summer data from 14 Wisconsin cisco lakes with a wide range of limnological characteristics indicated that TDO6 varied from 4.2 to 27.5 °C and CLT from −6.2 to 66.7 m. Cisco abundance across lakes was greater at lower values of TDO6 and higher values of CLT, and non-attainments of the proposed benchmarks were most likely in lakes with remnant or extirpated cisco populations. Non-attainment of benchmarks could occur from late June through September, and three or more samples across the entire summer would be required to have a reasonable probability of detecting a non-attainment in TDO6 or CLT within any given year. Across years, to detect a single year of non-attainment with an 80% level of confidence, two years of sampling would be sufficient for CLT and three years for TD06; to detect more than one non-attaining year, three years of sampling for CLT and six years of sampling for TD06 would be required. Despite relatively high temporal variation in some lakes, the proposed metrics and benchmarks appear to have value for assessing cisco oxythermal habitat in the Great Lakes region.

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