Effect of oil spillage on ecological diversity of pneumatophore associated fauna and flora in centralwest coast of India

Pneumatophores of Avicennia alba is rich in flora (diatoms) and faunal (meiofauna) diversity from the sedimentary environment. Flora and faunal composition from two sites: one polluted (Dighodi) and other non-polluted (Goa) was also compared. The pneumatophores of Dighodi and Goa harboured 21 and 15 diatom genera respectively. In Goa, the Shannon Wiener's Diversity index (H´) was 2.6 and 2.3 for sediment diatom community and pneumatophore diatom community respectively while in Dighodi, it was less i.e. 2.4 and 1.7 respectively. Centrale diatoms dominated in case of sediment while pennales dominated on the pneumatophore surface. In Goa, the diatom community was dominated by Nitzschia (1203 cells/1 cm²) and Coscinodiscus (1876 cells/1 cm ²) for pneumatophore and sediment substratum respectively; but in Dighodi, the dominant diatom was Navicula (2951 cells/1 cm²) and Bacillaria (1671 cells/1 cm²) respectively. In contrast to pneumatophores, sediment diatom community showed some variations. The effect of oil pollution was clearly seen on both meiofauna and flora. In both cases reduction in number and diversity due to oil pollution were noticed. This preliminary investigation not only generated baseline data but also highlights the hidden biodiversity associated with pneumatophores.