Lake Palmas (A = 10.3km2) is located in the Lower Doce River Valley (LDRV), on the southeastern coast of Brazil. The Lake District of the LDRV includes 90 lakes, whose basic geomorphology is associated with the alluvial valleys of the Barreiras Formation (Cenozoic, Neogene) and with the Holocene coastal plain. This study aimed to investigate the relationship of morphometry and thermal pattern of a LDRV deep lake, Lake Palmas. A bathymetric survey carried out in 2011 and the analysis of hydrographic and wind data with a geographic information system allowed the calculation of several metrics of lake morphometry. The vertical profiling of physical and chemical variables in the water column during the wet/warm and dry/mild cold seasons of 2011 to 2013 has furnished a better understanding of the influence of the lake morphometry on its structure and function. The overdeepened basin has a subrectangular elongated shape and is aligned in a NW-SE direction in an alluvial valley with a maximum depth (Zmax) of 50.7m, a volume of 2.2×108 m3 (0.22km3) and a mean depth (Zmv) of 21.4m. These metrics suggest Lake Palmas as the deepest natural lake in Brazil. Water column profiling has indicated strong physical and chemical stratification during the wet/warm season, with a hypoxic/anoxic layer occupying one-half of the lake volume. The warm monomictic pattern of Lake Palmas, which is in an accordance to deep tropical lakes, is determined by water column mixing during the dry and mild cold season, especially under the influence of a high effective fetch associated with the incidence of cold fronts. Lake Palmas has a very long theoretical retention time, with a mean of 19.4 years. The changes observed in the hydrological flows of the tributary rivers may disturb the ecological resilience of Lake Palmas.

Mine tailing dam bursts occur frequently with attendant implications for the environment and human populations. Institutional preparedness for such events plays an important role in their lasting impact. This study analyzes the stakeholder engagement in the newly governance framework created to recover the Doce River ecosystem following the 2015 disaster, where 34 million m 3 of tailings were released, killing 19 people and causing massive impacts on riverine life. Following the disaster, poorly conceived political and management decisions impeded and continue to impede the progress of ecosystem recovery. The post-event management structure shows a centralized and poorly diverse stakeholder pool. We conclude that poor governance structure, and weak law enforcement, are among the main reasons preventing the Doce River post-disaster watershed recovery. A watershed vulnerability analysis combined combining dam stability and socioeconomic data, concluding concluded that low ratings of socioeconomic performance substantially increases basin vulnerability. We recommend that the watershed committee should be fully involved in the implementation of the program and take a central role so that the most vulnerable communities (including indigenous people) take ownership of ecosystem recovery, including indigenous people.

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The water-mixing regime, light availability, nutrient limitation and trophic state were evaluated for the Duas Bocas Reservoir (DBR; Espírito Santo State, southeastern Brazil), a small (0.51 km 2 ), shallow (z max < 10 m) water supply reservoir located in a conservation area. Monthly water sampling was conducted for the lacustrine zone (z max = 10 m) next to the water withdrawal tower, during one hydrological cycle (October 2002 to September 2003. Water samples were taken at four depths in this area, including subsurface, Secchi depth, euphotic ⁄ aphotic boundary and near the bottom of the lake. The variability of the reservoir's limnological features defined two periods. Period 1, comprised of the summer months (October to April), was characterized by strong thermal stratification, nutrient limitation in the mixing layer, a metalimnetic biomass maximum and anoxia and high nutrient concentrations in the hypolimnion. Period 2, comprised of the winter months (May to September), was characterized by overturn events during which the phytoplankton population experienced light limitation. The observed water-mixing regime was characteristic of warm monomictic system, presenting atelomixis, the incomplete vertical mixing of stratified water masses. The average total phosphorus and chlorophyll-a concentrations suggested a meso-eutrophic water system. The nutrient concentrations exhibited nitrogen and phosphorus limitation, suggesting that nutrients, rather than light, limit or regulate the phytoplankton biomass in the DBR for most of the year.

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