Global Journal of Science Frontier Research, H: Environment & Earth Science, Volume 22 Issue 5

© 2022 Global Journals 1 Global Journal of Science Frontier Research Volume XXII Issue V Year 2022 52 ( H ) Version I Evidence of Sediment Sterility and Benthic Quality as Deleterious Consequences After the 2019 Oil Spill in Northeastern Brazil Processing of sediments followed standard procedures, where a fixed volume of 50 cm 3 of sediment was washed over a 63 µm sieve. After drying in an oven at 60°C for 48 hours, samples were split using a micro splitter into subsamples of at least 100 living foraminiferal specimens. Species identification and counting of dry specimens were done under an optical microscope. Our methods follow Eichler et al. (2007) for benthic analysis and Eichler et al. (2019) on the sampling of coral reefs using scuba divers, and Hallock (1999) were used as a taxonomic reference for symbiont-bearing foraminifera. Our data are based on living counts, even though there is a belief that Rose Bengal method can overestimate the abundance of living foraminifera (Bernhard et al., 2006). Scanning electron micrographs were obtained to clarify identifications. Field recording of water temperature, salinity, and oxygen were performed using a multiprobeMetler Toledo, but, within either area, they did not show any noticeable variations or trends. b) Numerical Analyses Univariate Techniques: Univariate data of Pielou Evenness (J’), Shannon-Wiener Diversity {H’ (loge)}, and Simpson Dominance indices (Zar, 1984) were computed to assess changes in community structure. Multivariate Analyses: Were applied to foraminiferal data [cluster analysis] producing a ‘‘map’’ of samples in which the placement of samples reflects the similarity of their biological communities and environmental patterns, rather than their simple geographical location. The numerical procedures of diversity, dominance and evenness, and cluster were carried out using a University of Plymouth computer program PRIMER v6 (Plymouth Routines in Multivariate Ecological Research PRIMER-E Ltd., Plymouth) which is described in Clarke (1993), Clarke and Warwick (1994), and (Clarke and Ainsworth, 1993). V. R esults Table 1 show sampling positions and depth at the time of collection of samples in 2019. Table 1: Location and Depth of Collected Samples.