Editorial

Abstract

Acta is the fourth thematic number published by our periodical in past six years. The first thematic number was published in 2010 (n o 2, vol. 22), on aquatic macrophytes; the second was published in 2013 (n o 3, vol. 25), comprising articles on the coastal lagoons of northern Rio de Janeiro state; and the third as published in 2014 (n o 2, vol. 26), bringing studies conducted in the south region of Brazil. The current number was proposed by Professor Joseline Molozzi, a teacher at the Biology Department and the Ecology and Conservation Graduate Program at "Universidade Estadual da Paraíba". Her intention was to produce an issue containing articles developed in the Brazilian semiarid region, which has particular climatic characteristics, with long periods of drought and low annual rainfall, reaching the extreme of annual 300 mm, reflecting the adaptive changes to which the aquatic communities are subject to. Moreover, it was in the Brazilian semiarid region that Stillman Wright (North American researcher) developed the first essentially limnological works in Brazil. Wright intensely studied reservoirs located near the city of Campina Grande (Paraíba state), including the Bodocongó dam, which is considered the cradle of the Brazilian Limnology. The works of this researcher draw attention to the chemical peculiarities of the water, where the typical prolonged droughts in the region and the high concentrations of chlorides and carbonates characterized the dams as eutrophic, but as a typical characteristic of the region. Therefore, taking into account the specific characteristics of the semiarid region and its historical importance, we contacted several researchers from the northeast region of our country and asked them to submit studies for this thematic number. We would like to emphasize that the procedures for publication were the same ones adopted for numbers containing spontaneous demand papers, that is, the manuscripts underwent rigorous peer review and analysis by the editors. Thus, this number contains 11 articles of different approaches to various aquatic communities (fish, phytoplankton, cyanobacteria, rotifers) and several systems, ranging from temporary rivers and reservoirs, to researches carried out in solar saltern the northernmost coast of the region. Acta has contributed to theoretical and conceptual themes in Limnology and Ecology, as well as to aspects of the use and conservation of aquatic ecosystems. This way, the articles here presented portray topics related to basic and applied Limnology, especially to aquatic ecosystems of the Brazilian semiarid region. We are grateful to the researchers who contributed to this thematic number by presenting opinions, and especially to those who submitted manuscripts for evaluation.

Herbicides and the Environment

“…The most coherent explanation for this is that, as time passes, the pesticides become diluted and dissipate, thus decreasing their toxicity to the aquatic organisms (Schulz & Liess, 1999). However, Molozzi et al (2007) did was not record temporal differences in the benthic community in relation to the stages of the rice seedling.…”