Márcia Divina de Oliveira

Flood pulse influence on phytoplankton communities of the south Pantanal floodplain, Brazil

Four sites situated on the Pantanal floodplain (Paraguay River and floodplain) were sampled throughout the annual cycle, mainly during the rising water period, with the aim of evaluating the effects of the flood pulse on the composition and population densities of the phytoplanktonic communities. Comprehensive water chemistry data were collected. Eighty-two taxa were found, numerically dominated by Chlorophyceae (23 taxa). Cryptophyceae (principally Cryptomonas brasiliensis) occurred in all samples, and were responsible for 47–58% of the phytoplankton abundance in the studied area. Highest phytoplanktonic population density was at the rising water period, when the limnological changes are most marked as the river water first enters into contact with the floodplain. During this period, when intense decomposition occurs, the Cryptophyceae decreased and the Euglenophyceae increased, except at site 1 (Castelo Lake), where this group were more stable during the year, representing 35–56% of the phytoplankton. In the falling water period (September and October), the phytoplankton was also represented by Bacillariophyceae and Cyanophyceae. In the Pantanal, the great abundance and sometimes dominance of Cryptophyceae, may be due largely to adverse conditions for the development of other groups; the former are adapted to low availability of dissolved nutrients, and high water transparency, such conditions prevailing during the high water period.

Limnoperna fortunei (Dunker, 1857) (Mollusca, Bivalvia, Mytilidae): first record in the São Francisco River basin, Brazil

Limnoperna fortunei (Dunker, 1857) is a small mytilid native to Southeast Asia. It was introduced in South America in early 1990 and has dispersed from Argentina to central Brazil, and until 2014 has been restricted mainly to the Parana and Uruguay river basins. The present note reports the occurrence of Limnoperna fortunei for the first time in the Sao Francisco River basin in northeastern Brazil. The establishment of L. fortunei in these regions will require close attention from the government and also by society.

A fuzzy logic-based tool to assess beef cattle ranching sustainability in complex environmental systems

One of the most relevant issues in discussion worldwide nowadays is the concept of sustainability. However, sustainability assessment is a difficult task due to the complexity of factors involved in the natural world added to the human interference. In order to assess the sustainability of beef ranching in complex and uncertain tropical environment systems this paper describes a decision support system based on fuzzy rule-approach, the Sustainable Pantanal Ranch (SPR). This tool was built by a set of measurements and indicators integrated by fuzzy logic to evaluate the attributes of the three dimensions of sustainability. Indicators and decision rules, as well as scenario evaluations, were obtained from workshops involving multi-disciplinary team of experts. A Fuzzy Rule-Based System (FRBS) was developed to each attribute, dimension and general index. The essential parts of the FRBS are the knowledge database, rules and the inference engine. The FuzzyGen and WebFuzzy tools were developed to support the FRBS and both showed efficiency and low cost for digital applications. The results of each attribute, dimension and index were presented as radar graphs, showing the individual value (0-10) of each indicator. In the validation process using the WebFuzzy, different combinations of indicators were made for each attribute index to show the corresponding output, and which confirm the feasibility and usability of the tool.

Chemical Strategies for the Control of the Golden Mussel (Limnoperna fortunei) in Industrial Facilities

There are a number of available chemical strategies for the control of macrofouling by bivalves within piping systems such as those that carry raw water into water treatment plants, cooling water to vital areas of power plants and industrial facilities, and fire protection water in any industry. A number of these strategies have been tested for the control of golden mussels and some of the methods tested hold promise for industrial use. Treatment strategies generally fall into proactive and reactive treatments. Proactive treatments will prevent settlement of mussels or prevent the development of adults. Reactive treatments will allow the settlement and growth of adult mussels, periodically removing settled adults. The chemicals used for both strategies are divided into nonoxidizing and oxidizing chemicals. The actual choice of chemicals and the mode of application will depend on several factors such as regulatory approval, economic viability, and preference of the individual user.

Alternative Strategies for Control of Golden Mussel (Limnoperna fortunei) in Industrial Facilities

There are numerous chemically based control strategies for macrofouling by bivalves within piping systems such as those that carry raw water into water treatment plants, cooling water to vital areas of power plants and industrial facilities, and fire protection water in any industry. As the use of chemicals is continuously scrutinized by regulators in many countries, alternative control strategies for macrofouling control are increasing in popularity. Nonchemical controls such as filtration, ultraviolet light, electric currents, acoustics, manipulation of water velocity, magnetic fields, turbulence, and sacrificial substrates have been tested and in some cases are being utilized for macrofouling control in industrial settings. In some cases, these alternative strategies are limited in their applicability by either plant design or quality of the raw water, but they are generally seen as more environmentally friendly as they do not result in release of chemicals when the cooling water is returned to the environment.