Benthic ostracods (crustacean) as a nearshore pollution bio-monitor: examples from the Red Sea Coast of Egypt.

Abstract

Benthic ostracods are deemed as one of the most useful micro-fauna for biomonitoring in shallow marine ecosystem, which are sensitive to environmental changes that can be reflected by their diversity and abundances. The pollution leads to high dominance index and low abundance ostracod communities. Therefore, eighteen sediment samples were collected from Ras Gharib and Quseir sites, along the Red Sea coast, to assess the ostracods response toward the anthropogenic environmental disturbances. Jugosocythereis borchersi, Alocopocythere reticulata, and Loxocorniculum ghardaqensis are the most abundant ostracods in the study localities. To evaluate the linkage between ostracods and contaminated sediments, metal concentrations in the sediments were measured using inductively coupled plasma optical-emission spectrometry (ICP-OES). We observed a significant spatial difference in elemental distribution in sediment samples, and some elements are of higher contributions than the average marine sediment composition. The quantitative analysis of benthic ostracod associations was processed statistically with geochemical data and differentiated the study area into two environments, based on the degrees of contamination. Quseir is encompassing the most contaminated stations. It is characterized by sediments richer in heavy metals, higher silt, and higher organic matter contents. Contaminated environments favor the presence of pollution-tolerant species (e.g., J. borchersi, C. torosa, L. ghardaqensis, G. triebeli, M. striata, A. reticulata, and partly, C. dimorpha). Conversely, Ras Gharib is less polluted with metals and organic matter, and is characterized by pollution-sensitive species (X. rhomboidea). Noteworthy, a low density of ostracods was observed at the expense of the diversity around contaminated stations of the Quseir site.