BENTHIC FORAMINIFERAL PROXIES FOR POLLUTION MONITORING IN AL-MUKALLA COASTAL AREA, HADRAMOUT GOVERNATE, REPUBLIC OF YEMEN

Abstract

The coastal waters of Al-Mukalla, Hadramout Governate, Republic of Yemen, receive considerable amounts of treated and untreated domestic and industrial effluents, which carry a variety of contaminants including heavy metals. We surveyed benthic foraminiferal assemblages as potential indicators for pollution and collected geochemical, sedimentological and water-quality data. Cluster and canonical correspondence analyses delineated three areas: unpolluted areas east and west of Al-Mukalla harbor (biofacies I), a moderately polluted area in and around the harbor (biofacies II), and a highly polluted site within the main harbor (biofacies III). Biofacies I is characterized by sandy sediments with moderate proportions of CaCO 3 , low total organic matter and low heavy metal concentrations. This biofacies is characterized by pollution-sensitive smaller species ( Ammonia parkinsoniana , Discorbinella bertheloti and Pararotalia nipponica ). Biofacies II includes sites exposed to southwest monsoon winds, which are characterized by coarse sand relatively rich in CaCO 3 , as well as more protected sites that are somewhat more muddy, with somewhat higher concentrations of organic matter and heavy metals. Foraminiferal assemblages include larger taxa ( Amphistegina lessonii , Peneroplis pertusus , Neorotalia calcar , and Sorites orbiculus ), as well as smaller species ( Elphidium crispum , Glabratella patelliformis , and Discorbis turbo ). Biofacies III is found at a relatively muddy site that is rich in organic matter and heavy metals, particularly Cu and Zn. The foraminiferal assemblage is characterized by pollution-tolerant species, including Ammonia tepida , E. advenum , E. gerthi , Quinqueloculina eburnea , Q. bosciana , Haynesina germanica and Bolivina variabilis . The deleterious effects of pollution on the foraminiferal assemblage of biofacies III are clearly manifested by the highest incidences of test deformation.