Fish kills at Neotropical hydroelectric power plants, particularly those driven by total dissolved gas (TDG) supersaturation, are difficult to diagnose and quantify due to data scarcity and rapid carcass decomposition. This study proposes a novel framework to address these challenges by (1) inferring TDG saturation from more readily available Dissolved Oxygen (DO) data, using thermodynamic principles and (2) estimating true daily mortality through a Bayesian multistate model that accounts for decomposition stages and catchability. Applied to a fish kill event at an Amazonian dam, the models showed that TDG levels can be accurately inferred from DO data and that direct carcass counts severely underestimate the magnitude of mortality events due to low detection probabilities. Furthermore, these results revealed a significant temporal lag between the actual mortality peak and carcass recovery. This integrated methodology offers a robust framework for quantifying impacts, expanding monitoring capacity, and supporting more rigorous environmental licensing processes in the Neotropical region.

This study investigated the zooplankton community structure in Gołdap Lake, located in the northeastern part of Poland. Due to the many years of uncontrolled inflows of pollutants, the ecological condition of the lake has deteriorated. Despite many remedial actions in the catchment, the internal nutrient load of the lake was too great to improve its condition. This goal required additional in-situ activities. The restoration of Gołdap Lake started in 2017. The substance which was used for restoration purposes was Phoslock®. It is lanthanum-modified clay that can bind phosphate into insoluble rhabdophane-(La). Water and zooplankton samples were collected from September 2017 to August 2021. A total of 70 species, including 44 rotifers, 16 copepods, and 10 cladocerans species, were detected during the research period. The whole zooplankton community was divided into 7 functional groups: rotifer filter feeders (RF), rotifer carnivores (RC), small crustacean filter feeders (SCF), mid-sized crustacean filter feeders (MCF), mid-sized crustacean carnivores (MSC), large crustacean filter feeders (LCF) and large crustacean carnivores (LCC). The most abundant were species from the rotifer filter feeder functional group. This study showed a significant correlation between dominant zooplankton groups and environmental variables such as nitrite nitrogen, water temperature, dissolved oxygen, conductivity, biological oxygen demand, and dissolved organic carbon. According to the values of zooplankton-based indices, the ecological state of Gołdap Lake hadn't changed during the research period. The major driving factors which affect the structure of zooplankton were: poor quality of food base, top-down pressure of planktivorous fish, and competition between zooplankton groups.

Woody vegetation cover in South Africa has increased over the past 100-150 years owing to the establishment of commercial forestry plantations, the spread of alien invasive plants (AIPs) and indigenous woody encroachment (WE). Extensive research conducted over the past 50 years has shown that AIPs can lead to dramatic declines in catchment water yields as a result of their high evapotranspiration (ET) rates. This has raised concern that WE may also be responsible for increasing ET losses and adversely impacting the country's limited water resources. In this paper, we used a combined systematic review and meta-analysis approach to explore trends in the water use of different vegetation types located in various climates across South Africa, to ultimately evaluate the likelihood of WE increasing ET losses in South Africa's savannas. This study revealed mixed support for whether WE in South Africa's savannas is increasing ET losses. On one hand, the fact that WE species replace grasses and form dense thickets indicates that there is high potential for WE to increase ET losses. On the other hand, rainfall, appears to be a primary factor limiting ET in semi-arid climates, indicating little potential for WE to have any effect on ET, unless there is an above-average rainfall year, or the vegetation has access to an additional water source. This study justifies the need for additional ET monitoring in South Africa's savannas in order to determine whether large-scale WE control should be implemented to conserve water resources in one of the country's driest regions.