T-Chain
Modelling prolonged stratification and hypoxia in dryland river waterholes during drought conditions
2023 - Peisheng Huang, Jonathan C. Marshall, Jaye Lobegeiger, Rebecca L. Cramp, Monique A. Parisi, Craig E. Franklin, Andrea Prior, Kamilla Kurucz & Matthew R. Hipsey
Dryland river waterholes provide critical habitat and serve as refugia for aquatic animals during droughts, but the quality of these waterholes can often be severely compromised by hypoxic conditions that can lead to mass fish kills and loss of biodiversity. To assist river management, we developed a waterhole-scale ecohydrology model representing thermal stratification and dissolved oxygen regimes during prolonged drought periods in northern Murray-Darling Basin dryland rivers in Queensland, Australia. Model development focused around 6 typical waterholes in these rivers that were shallow (<5 m deep), highly turbid, and stratified with low dissolved oxygen.
Dryland river waterholes provide critical habitat and serve as refugia for aquatic animals during droughts, but the quality of these waterholes can often be severely compromised by hypoxic conditions that can lead to mass fish kills and loss of biodiversity. To assist river management, we developed a waterhole-scale ecohydrology model representing thermal stratification and dissolved oxygen regimes during prolonged drought periods in northern Murray-Darling Basin dryland rivers in Queensland, Australia. Model development focused around 6 typical waterholes in these rivers that were shallow (<5 m deep), highly turbid, and stratified with low dissolved oxygen.
Phosphorus and Oxygen Dynamics between Fall and Spring Turnover Events in a Small Canadian Shield Lake
2022 - Ghane, Alireza
"In dimictic lakes, the stable density stratification during summer and winter inhibits vertical mixing of nutrients and oxygen. This favors the development of hypolimnetic hypoxia, which degrades cool-water fish habitat and enhances nutrient mineralization and diffusion from the sediments. Fall turnover began once the entire water column become nearly isothermal (within 0.4 °C) at the deepest point of the lake and continued to the onset of winter stratification. Similarly, spring turnover began when the water column became nearly isothermal (within 0.4 °C) and continued until the average water column temperature reached 4.0 to 4.5 °C. "
"In dimictic lakes, the stable density stratification during summer and winter inhibits vertical mixing of nutrients and oxygen. This favors the development of hypolimnetic hypoxia, which degrades cool-water fish habitat and enhances nutrient mineralization and diffusion from the sediments. Fall turnover began once the entire water column become nearly isothermal (within 0.4 °C) at the deepest point of the lake and continued to the onset of winter stratification. Similarly, spring turnover began when the water column became nearly isothermal (within 0.4 °C) and continued until the average water column temperature reached 4.0 to 4.5 °C. "
On biogenic turbulence production and mixing from vertically migrating zooplankton in lakes
2018 - Stefano Simoncelli, Stephen J. Thackeray & Danielle J. Wain
Vertical mixing in lakes is a key driver of transport of ecologically important dissolved constituents, such as oxygen and nutrients. In this study we focus our attention on biomixing, which refers to the contribution of living organisms towards the turbulence and mixing of oceans and lakes. While several studies of biomixing in the ocean have been conducted, no in situ studies exist that assess the turbulence induced by freshwater zooplanktonic organisms under real environmental conditions. Here, turbulence is sampled during three different sampling days during the sunset diel vertical migration of Daphnia spp. in a small man-made lake.
Vertical mixing in lakes is a key driver of transport of ecologically important dissolved constituents, such as oxygen and nutrients. In this study we focus our attention on biomixing, which refers to the contribution of living organisms towards the turbulence and mixing of oceans and lakes. While several studies of biomixing in the ocean have been conducted, no in situ studies exist that assess the turbulence induced by freshwater zooplanktonic organisms under real environmental conditions. Here, turbulence is sampled during three different sampling days during the sunset diel vertical migration of Daphnia spp. in a small man-made lake.
Sensor-based quality control of raw water
2018 - "Esmeralda Frihammar, Madeleine Gobl, Jennifer Jonsson, Ylva Kjellgren, Alexi Lampinen, Lina Oskarssonoch, Mathias Wallin "
This report was carried out on behalf of the company Norrvatten, which operates the Görvälnverket water plant in Jakobsberg outside Stockholm. The study is divided into three main objectives. The first goal involves performing an analysis of existing measurement data from a sensor located inside the water plant. Data from the plant was compared with weather data to bring out possible connections. Information about connections could lead to Norrvatten being able to use its measuring equipment more efficiently. MatLab was used in the analysis and certain relationships between TOC (Total Organic Carbon), precipitation and water levels could be seen and clear seasonal trends could also be discerned.
This report was carried out on behalf of the company Norrvatten, which operates the Görvälnverket water plant in Jakobsberg outside Stockholm. The study is divided into three main objectives. The first goal involves performing an analysis of existing measurement data from a sensor located inside the water plant. Data from the plant was compared with weather data to bring out possible connections. Information about connections could lead to Norrvatten being able to use its measuring equipment more efficiently. MatLab was used in the analysis and certain relationships between TOC (Total Organic Carbon), precipitation and water levels could be seen and clear seasonal trends could also be discerned.
Internal wave-driven transport of fluid away from the boundary of a lake
2013 - Danielle J. Wain, Michael S. Kohn, Joshua A. Scanlon, Chris R. Rehmann
A field experiment was conducted to study transport of fluid from the boundary to the interior of a lake. Tracking of a tracer injected into the metalimnion was combined with measurements of meteorological forcing, internal waves, and temperature microstructure. Seiches of vertical mode 2 and horizontal modes 1 and 2 were initiated after a wind event, and the tracer moved 950 m into the interior after 29.2 h. Four potential mechanisms for spreading of the tracer from the boundary to the interior were considered: intrusions from boundary mixing, horizontal dispersion, advection by seiches, and advection and dispersion driven by internal waves.
A field experiment was conducted to study transport of fluid from the boundary to the interior of a lake. Tracking of a tracer injected into the metalimnion was combined with measurements of meteorological forcing, internal waves, and temperature microstructure. Seiches of vertical mode 2 and horizontal modes 1 and 2 were initiated after a wind event, and the tracer moved 950 m into the interior after 29.2 h. Four potential mechanisms for spreading of the tracer from the boundary to the interior were considered: intrusions from boundary mixing, horizontal dispersion, advection by seiches, and advection and dispersion driven by internal waves.
