Exploring the temporal dynamics of methane ebullition in a subtropical freshwater reservoir.

The transport of methane from sediments to the atmosphere by rising gas bubbles (ebullition) can be the dominant, yet highly variable emission pathway from shallow aquatic ecosystems. Ebullition fluxes have been reported to vary in space and time, as methane production, accumulation, and bubble release from the sediment matrix is affected by several physical and bio-geochemical processes acting at different timescales. Time-series analysis and empirical models have been used for investigating the temporal dynamics of ebullition and its controls.

Microbiological water quality assessment of sewage discharge through Barra da Tijuca (Rio de Janeiro, Brazil) submarine outfall.

Submarine outfalls have been employed to convey urban effluents to their fate in the open ocean due to their dilution capacity and organic matter decay. This work analysed Escherichia coli concentrations in the Barra da Tijuca (Rio de Janeiro, Brazil) submarine outfall plume, considering an hourly variable bacterial die-off due to environmental parameters associated with dynamic changes, vertical plume position, and thickness in response to hydrodynamic conditions. The adopted modelling procedure included coupling a near-field mixing zone model, NRFIELD, with the far-field Lagrangian transport and water quality model of the SisBaHiA® ( http://www.

Mapping of suspended sediment transport using acoustic methods in a Pantanal tributary.

Generally, fluvial systems are used for different objectives including energy production, water supply, recreation, and navigation. Thus, many impacts must be considered with their use. An understanding of sediment dynamics in fluvial systems is often of value for a variety of objectives, given that erosion and depositional processes can change the fluvial system morphology and can substantially alter the fluvial environment.

Benchmarking for using an acoustic Doppler current profiler for bathymetric survey.

This research aims to improve data post-processing from an acoustic Doppler current profiler (ADCP) to obtain additional depth information with a high-quality bathymetric result. To validate the depth, dataset in a control area was used a scaled rod, the RTK (Real-Time Kinematic) positioning technique, and a single beam echo sounder (SBES). The developed post-processing and validation in the control area applied to a small region of a water supply reservoir in Brazil.

Implementation of comparative detection approaches for the accurate assessment of sediment thickness and sediment volume in the Passaúna Reservoir.

Siltation has significant economic and social impacts as it directly reduces the useable amount of water in reservoirs. Giving a solution to the issue of sedimentation is a complicated task and maybe one of the most important engineering and environmental challenges of the 21 century. The deposited volume and the distribution pattern of the sediment are often unknown and not easy to assess.

Can seawater desalination be a win-win fix to our water cycle?

While we increasingly turn to desalination as a secure water supply, it is still perceived as an expensive and environmentally damaging solution, affordable only for affluent societies. In this contribution, we recast desalination from one of a last resort to a far-reaching, climate change mitigating, water security solution. First, we argue that the benefits of desalination go beyond the single-use value of the water produced.

Correction to: High-frequency measurements of gas ebullition in a Brazilian subtropical reservoir-identification of relevant triggers and seasonal patterns.

The original version of this article unfortunately did not contain all information in Figure 3.

High-frequency measurements of gas ebullition in a Brazilian subtropical reservoir-identification of relevant triggers and seasonal patterns.

Water bodies, either natural or constructed impoundments, are sources of methane to the atmosphere, in which ebullition is frequently mentioned to be the dominant pathway. Ebullition is a complex process that is spatially dependent on factors acting over large distances (atmospheric pressure changes, wind) and factors acting locally (sediment characteristics, gas production) and is temporally variable due to the parameters' oscillation with time. Its quantification through measurements is still limited, as is the identification of production processes and triggers for ebullition.

A method for the assessment of long-term changes in carbon stock by construction of a hydropower reservoir.

Sustainability of hydropower reservoirs has been questioned since the detection of their greenhouse gas (GHG) emissions which are mainly composed of carbon dioxide and methane. A method to assess the impact on the carbon cycle caused by the transition from a natural river system into a reservoir is presented and discussed. The method evaluates the long term changes in carbon stock instead of the current approach of monitoring and integrating continuous short term fluxes.

Long-term hydrodynamic modeling of the Arabian Gulf.

A 3-D prognostic baroclinic hydrodynamic model of the Arabian Gulf (AG) was developed using Delft3D-FLOW. The model was forced with long-term time averaged climatological data over the computational domain and long-term salinity and temperature boundary conditions applied at its tidal open boundary. The model simulation results were thoroughly validated against measured tides from 5 stations and measured currents at 4 locations in the central and southern parts.

Dynamic coupling of near field and far field models for simulating effluent discharges.

In many cases, (processed) wastewater or thermal effluents are discharged into the marine environment, rivers or lakes. To accurately determine the dispersion, recirculation and environmental impacts of outfall plumes, it is important to be able to model the different characteristics of the outfall plume in detail - from the near field (metres around the outfall) to the far field (up to kilometres away). The solution for engineering practice is to combine different types of models (near and far field models) that each focus on specific scales, with corresponding optimised resolutions and processes.

Occurrence of selected estrogens in mangrove sediments.

This paper presents results related to the occurrence and distribution of estrogens along the Brazilian coast. Three mangrove areas were chosen to evaluate the presence of estrogens in surface sediments of mangrove forests. The presence of estrogens was observed in all studied sites.