Impact of ‘Chitra’ Oil Spill on Tidal Pool Macrobenthic Communities of a Tropical Rocky Shore (Mumbai, India)

Abstract

A collision between the ships, MSC Chitra and MV Khalijia 3 in the mouth region of Mumbai Harbour led to a leakage of around 800 t of fuel oil in August 2010, affecting rocky intertidal region of Colaba. To evaluate the impact of this catastrophic event on the resident biota, a 15-month long sampling programme was initiated in the oil affected area immediately after the spill. Petroleum hydrocarbons in water and sediment organic carbon values were high just after the oil spill but subsequently decreased in the following months. In total, 70 macrobenthic taxa were identified. Univariate diversity indices indicated that while the ecological status of the site, albeit briefly, was affected during August 2010, a healthy environment prevailed subsequently. Cluster and MDS analyses distinctly segregated the oil impacted monsoon months from the other sampling months. BIOENV analyses indicated that petroleum hydrocarbons and organic carbon were the anthropogenic parameters influencing macrobenthic community structure. BOPA index was used to evaluate ecological quality of the study area as the index is sensitive to oil pollution. Low BOPA values throughout the study period indicated that the environment was good with few opportunistic species. Comparison with past data revealed that the oil spill did not have long term deleterious effects on the macrobenthic species diversity of this rocky beach and reasons thereof are discussed.

Marine Macrobenthos of NorthWest India-Reviewing the Known and Unknown

“…From three rocky beaches, around 50 macrobenthic species were reported which included 41 gastropods and 5 pelecypods. In a later study, 70 macrobenthic taxa, were identified in the rocky pools of the intertidal area of Colaba, Mumbai (Sukumaran et al, 2014). Around 30 and 34 species of macrobenthos dominated by molluscs were identified from the Haji Ali and Marine Drive intertidal zones (Balasaheb et al, 2017).…”

“…Univariate indices were applied more frequently in environmental studies, probably due to the ease of application (Quadros et al, 2009;Kulkarni et al, 2010Kulkarni et al, , 2011Sukumaran et al, 2013Sukumaran et al, , 2014Sukumaran et al, , 2016Naz et al, 2016;Dias et al, 2018;Takar et al, 2020). Several diversity indices (Shannon-Wiener, Index of frequency, Rarity index, Dominance and Evenness Indices, Margalef Richness Index) were applied to the macrobenthic density in various studies (Varshney and Govindan, 1995;Pawar and Kulkarni, 2007;Pawar et al, 2019).…”

“…The exclusion of monsoon data and averaging the status of the non-monsoonal seasons for the efficient application of benthic indices was recommended. Data transformations were observed to have no influence on the efficiency of AMBI (Dias et al, 2018;Mulik et al, 2020b;Mulik et al, 2020a).The Benthic Opportunistic Polychaeta Amphipoda (BOPA) index was applied to tidal pool communities of a tropical shore to evaluate the impact of an oil spill on intertidal ecology (Sukumaran et al, 2014).…”

“…An oil spill that occurred in the mouth region of Mumbai Harbor affected the rocky intertidal region of Colaba. A 15 month long study using macrobenthic diversity concluded that the area was only temporarily affected (Sukumaran et al, 2014). Another study that evaluated the impact of an oil spill on intertidal communities in the rocky beach of Uran, reported large scale mortality of brachyurans, decapods and large polychaetes at the high water line (Vijapure et al, 2016).…”

Isolation and Characterization of Bacteria from Refinery Effluent for Degradation of Petroleum Crude Oil in Seawater

“…Some of the most well-known oil spills that have taken place in last four decades include the Exxon Valdez in Alaska (1989), the 'Gulf War' in Kuwait (1991), the Erica in France (1999); the Aegean Sea in Galicia, Spain (1992) and the Prestige in Spain and France (2002) 1 . Recently, oil spills have occurred in India such as in Goa, West Coast of India in 2005 2 , Mumbai, Maharashtra in 2010 3 and Ennore, Tamil Nadu in 2017 4. Also, the transfer of petroleum crude oil (PCO) from Arabian countries such as Saudi Arabia and Iran to India is by the sea route through tanker vessels.…”