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

After the oil spill in 2019, the number of species (S) varies from 3 to 12, number of individuals (N) varies from 51 to 148, evenness (J’) varies from 0.62 to 0.99, diversity (H’) varies from 0.90 to 2.3, dominance (Lambda) varies from 0.1 to 0.46. Among stations which presented oil spots (P2, P3, P7, P8, P9, P12, P14, P18, P20, P21, P22) we observed that there of them are barren (P20, P21, P22) which had never happened in 2013 and 2014. With the exception of station P8 which presented the highest diversity, all other stations presented low numbers. Cluster analysis revealed in 2019 the formation of 4 groups: Group I: P1, P2*, P19, P24, P23, P25; Group II: P9*, P8*, P4, P3*, P10; Group III: P16, P6, P15, P17, P5, P12*, and Group IV: P11, P7*, P13, P14*, P18*. Group I encompass statios in the Pium River with the lowest diversities, Groups II and IV presents deeper stations with higher number of species and Amphisorushemprichii has higher proportions in those stations. Same result found in Pirangi 2013 and 2014 which groups were divided based on number of individuals and presence of symbionthic species SBS (Eichler and Moura, 2020). VI. D iscussion Local variables such as high hydrodynamic characteristics and other reworking processes are influencing the faunal distribution of foraminifers in this portion of the inner shelf. However, Eichler and Moura (2020) proposed that, at Pirangi Reefal area, where boats dock, and tourists walk upon the reefs, they observe the absence of well-preserved living Amphistegina , as well as higher diversity values from smaller taxa and opportunistic species rather than from SBF suggesting that coral communities in these areas may be at risk. The occurrence of oil spots in several stations at the moment of sampling (P2, P3, P7, P8, P9, P12, P14, P18, P20, P21, P22) revealed that the spill reached the bottom and the sediment and had immediate consequences for the benthic fauna. We therefore believe that Foraminifera data acts as reliable proxy for water quality and reef health at Rio Grande do Norte State sites. In addition, barren zones formed by stations P20, P21, P22, with no organisms, together with low evenness, probably dissolved due to the acidity due to the oil spill reaching the bottom in that specific area are overcome the already low numbered environment due to the transport and selection of tests by bottom currents, which prevent foraminifer settlement, suggesting that wave energy and exchange with open ocean waters are © 2022 Global Journals 1 Global Journal of Science Frontier Research Volume XXII Issue V Year 2022 54 ( H ) Version I Evidence of Sediment Sterility and Benthic Quality as Deleterious Consequences After the 2019 Oil Spill in Northeastern Brazil Figure 3: Cluster Revealing Four Groups of Stations Organized Based on the Number of Foraminifera Species.