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

Abstract

Predicting changes in reservoir conditions from climatic warming is hindered by the paucity of long-term data on temperature and thermal and oxygen structure replicated across a range of reservoir sizes. The present study characterizes seasonal patterns in temperature, thermal structure, and dissolved oxygen availability in reservoirs, and evaluates how critical periods for aquatic organisms (i.e., periods of maximum temperature and minimum oxygen) for these features are affected by atmospheric temperature anomalies at different time lags. Temperature and dissolved oxygen were measured from May through October at 1 m intervals from surface to bottom for 10 reservoirs sampled between 14 and 21 years during 1995-2016. For most temperature and oxygen metrics July was the period of thermal maxima and oxygen minima across reservoirs, exceptions were thermocline depth, which was static from May through October, and bottom water temperature which peaked in August. Surface water temperature of reservoirs increased 0.6 °C for every 1.0 °C increase in atmospheric temperature in July independent of reservoir area. Although the percentage of water that was oxic in July decreased with increasing July air temperatures, it increased with warming air temperatures from February to April. These long-term data derived patterns highlight the importance of reservoir size and lag periods in building a framework for predicting climate-induced changes in the thermal and oxygen environments of reservoirs, which have important implications for water quality and ecosystem processes and the associated dynamics of reservoir flora and fauna.

A long-term dataset of simulated epilimnion and hypolimnion temperatures in 401 French lakes (1959–2020)

“…Deep discharges could contribute to warmer bottom waters (Carr et al, 2020), whereas, in some cases, if the reservoir is shallow or if the discharge depth is not deep, it could demonstrate lake-like thermal behavior. This does not necessarily mean that, in this case, the entire functioning of the reservoir resembles one of a natural lake; there are still differences to consider (Detmer et al, 2021).…”

Fish and Prey Resources in Reservoir Coves with and without Offshore Artificial Habitat Structures

“…Similar to our study, Daugherty et al (2014) found CPUE and structure occupancy by centrarchids to be highest during fall sampling in a Texas reservoir supplemented with clusters of recycled Christmas trees but hypothesized that decreased spring CPUE could have been due to degradation and loss of structure complexity prior to their spring sampling efforts. Given that the structures we evaluated did not degrade between seasons, greater use of artificial structures during the fall compared to the spring may also be due to higher densities of age-0 fish or smaller, cover-seeking fish during the fall, attracting larger piscivores (Wege and Anderson 1979;Bolding et al 2004), as well as fish seeking structure in areas of thermal refuge because water temperatures remain elevated throughout the fall in Lake Shelbyville (Detmer et al 2022).…”

“…2004), as well as fish seeking structure in areas of thermal refuge because water temperatures remain elevated throughout the fall in Lake Shelbyville (Detmer et al. 2022).…”

Assessing the impact of climate change on dissolved oxygen using a flow field ecosystem model that takes into account the anaerobic and aerobic environment of bottom sediments

“…Hypoxia, the phenomenon of reduced dissolved oxygen (DO), is a water quality problem that adversely affects marine and lake ecosystems, and the decrease in DO is more pronounced in coastal areas, which receive pollution load from rivers, than in the open ocean, and it is not easy to elucidate the causes of anoxia. Many studies on anoxia and oxygen cycling have been conducted in closed water bodies that are subject to anthropogenic pollution, such as Lake Biwa, which is the target area of this study (Detmer et al 2022;Desgué-Itier et al 2023;Perlov et al 2023). In recent study, it is conducted a water quality future projection for the ocean and showed that phytoplankton occurring in the surface layer of the ocean in the world will decrease (Henson et al 2021).…”