Benthic foraminiferal assemblages and morphological abnormalities in the Subaé estuarine system, Bahia - Brazil

Several strategies can be adopted to characterize, evaluate and monitor environmental quality. Historically, the determination of physical-chemical variables by analytic methods has been prioritized in polluted areas. Nevertheless, there are several organisms, called bioindicators, which can be used as environmental indicators, being that the success of evaluation plans or environmental monitoring depends mainly on the correct choice of the bioindicator. Among the benthic organisms used for assessing anthropogenic effects, benthic foraminifera are one of the preferred groups because they are very sensitive to environmental stress. Studies dealing with benthic foraminifera as bioindicators of pollution have been increasing over the last decades. These studies have shown that the distribution of benthic foraminifers is affected by several anthropogenic stressors, like organic enrichment of the sediments, heavy metal load and petroleum hydrocarbons. Foraminiferal responses to these conditions can include shifts in abundance patterns, species composition and the presence of test's abnormalities. This study aims: 1) to record the benthic foraminiferal assemblages in the Subae Estuary (an impacted area); 2) to study the mineralogical test composition of those species that show high number of abnormal tests; 3) to relate this aspects to environmental conditions.