Effects of Simulated Oil Exposure on Two Intertidal Macrozoo Benthos: Tympanotonus fuscata (L) and Uca tangeri (Eydoux, 1935) in a Tropical Estuarine Ecosystem

Ewa-Oboho, Ita; Abby-Kalio, N. J.

doi:10.1006/eesa.1994.1049

Cited by 8 publications

(6 citation statements)

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“…Although a comparison between previous and present data on faunal biomass is hampered by large variance and sampling grid, some general trend appeared to be consistent, namely that biomass of species generally decreased with severity of oiling (Ewa-Oboho, 1994). This was the case in the present studies as biomass of taxa decreased with oiling effect.…”

Section: Faunal Population Densitiessupporting

confidence: 75%

“…Only a few opportunistic species will be found in large numbers shortly after-spill. In simulated oil spill studies Uca juveniles were found massively exterminated by oiling of the Bonny mud flat (Ewa-Oboho, 1994). Usually, opportunistic species are stress-enduring with very large population size and relatively high reproduction rates.…”

Section: Faunal Population Densitiesmentioning

confidence: 99%

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Studies on the short-term fffects of the mobil Idoho oil Spill on the Littoral Biota of Southeastern Nigeria

Ewa-Oboho¹,

Oladimej²

2009

West African Journal of Applied Ecology

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Quantitative surveys of the intertidal macro-fauna were conducted during September-October 1998 along transects established at various locations along the Nigeria coastline, following the rupture of a 24-inch pipeline at Idoho, off the Gulf of Guinea, southeastern Nigeria on 12 January 1998. Samples were taken within impacted areas and at control unpolluted sites approximately 5 km to the east of the Idoho off-shore platform. Spilled oil moved rapidly ashore and into river mouths, and estuaries and their mangals shortly after the spills. Biomass of macrofauna in the impacted areas tended to decrease with level of oiling, as the mean abundance decreased rapidly to about 50% of that found on the control unpolluted sites. Edible gastropod, mainly species of Tympanotomus fuscatus, and the brachyuran decapod, Uca tangeri, typically consumed by coastal inhabitants, had reduction in mean densities (up to 62%) in the oiled Bonny, Brass, Lagos and Forcados than in the non-oiled areas of Imo, Andoni and Cross River, showing partial recovery of the environment from the debacle after 9 months. The ecological implications of these findings are discussed. IntroductionA 24-inch oil pipeline ruptured at Mobil-Idoho platform on the inner shelf of the Atlantic coast of southeastern Nigeria on 12 January 1998 releasing over 40,000 bbls (approxi-mately 6,000 tones) of Qua Iboe light crude oil into the marine environment over the next three days. More than 700 km of the Nigerian coastline including estuaries were impacted. Within the impacted zone were a number of macro-benthic communities, the dominant species of which included the edible gastropod, Tympanotomus fuscatus, the Ocypodid brachyuran, Uca tangeri and Ocypode cursor, and several species of bivalves and polychaetes. Some of the estuaries that were oiled are known to be subject to pollution from a number of sources including hydrocarbon, sewage, metal, etc., showing that the spill was not in a pristine environment. It was, therefore, essential to include as many factors as possible in the sampling programme to look at the spill effects.In September 1998, 9 months after the oil came ashore, a rapid assessment survey was conducted at nearly all the estuarine/river mouths along the Nigerian coastline both within the oil impacted estuaries and at the clean control site, 5 km east of the ruptured point. This included measurement of physical and chemical parameters of sea water, and presence and absence of typical macrobiota, together with estimates of overall abundance at each site. Analysis of biota and physical characteristics demon-strated that a full range of Nigeria coastline habitat was present within the impacted area (Ewa-Oboho, 1998). As separation and classification of intertidal habitats were possible on the basis of macrobiota alone, this survey demonstrated that earlier predictions of massive species elimination were unfounded, and the result provided the basis for selection of permanent sites for longer-term studies published elsewhere (Ewa-Oboho, in press...

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Section: Faunal Population Densitiessupporting

confidence: 75%

Section: Faunal Population Densitiesmentioning

confidence: 99%

Studies on the short-term fffects of the mobil Idoho oil Spill on the Littoral Biota of Southeastern Nigeria

Ewa-Oboho¹,

Oladimej²

2009

West African Journal of Applied Ecology

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“…Rhizoclonium hieroglyphicum has been reported by many researchers to use crude oil as a source of food. It may appear to be affected by the crude oil (Ewa-Oboho, 1994). The algal species prefer smooth surfaces to rough ones as can be seen in the result where the smooth surface panel had higher recruitment than the rough ones.…”

Section: Discussionmentioning

confidence: 88%

“…These have made the estuarine environment very susceptible to crude oil pollution as a result of reduced wave action and tidal flushing. It also constitutes an additional stress for aquatic organisms (Sindermman, 1982;Ewa-Oboho, 1994;Ewa-Oboho and Oladimeji 2004).…”

Section: Introductionmentioning

confidence: 99%

Impact Of Crude Oil On Recruitment Of Epibenthic Organisms In Cross River Estuary, South East Nigeria

Ewa-Oboho¹,

Okon²

2009

Glo Jnl Pure Appl Sci

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Effects of crude oil on recruitment of epibenthic organisms in Cross River estuary were studied in February and March, 2007 on wooden Panels (15×15×1.5cm). The panels were immersed in Nigerian light crude oil and later suspended in the estuary for six weeks. Rhizoclonium hieroglyphicum showed slight resistance to the effect of the crudeoil while species like Balanus balanoide, Crassostrea gazar, Bugula neritina, Serbellaria intoshi, Catenella opuntia and Caloglossa leprieurii showed slight inhibition. Statistically, there was however no significant difference in the recruitment level of the organisms on both the control panels and oil-polluted panels, (p>0.05). This may probably have been as a result of weathering process or bacterial degradation of the crude oil which rapidly diluted the hydrocarbon, thereby reducing its toxicity. The result reveals that widespread oil spill during the reproductive season would reduce larval settlement and impede subsequent recruitment. The ecological implications of these findings are discussed.

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“…Exploration, exploitation, drilling transportation, processing and storage of crude oil have greatly affected the marine environment (Richard et al, 1978;Doerter, 1992;Ewa-oboho and Abby Kalio, 1994). The majority of oil pollution occurs in the estuaries and near shore waters (Richard et al, 1978;Brown et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Effects of crude oil on the gastropod, tympanotomus fuscata in the Cross River Estuary, south-east Nigeria

Ewa-Oboho¹,

Otogo²

2010

Glo Jnl Env Res

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Edible periwinkle, Tympanotonus fuscata, was collected from the Cross River estuary, allowed to acclimate to laboratory conditions for a week and then exposed to Nigerian light crude oil at different concentrations of 50ml, 100ml, and 150ml per litre of water for a period of 96 hours. Mud (80g) was added to all the 4-litre aquaria used for the experiment. The oil was thoroughly mixed with the estuarine water by stirring vigorously. During the 4-days experimental period, most of the specimens suffered suffocation and became moribund and mortality recorded. Within the first 24 hours mortality was absent in the 50ml and 100ml concentrations, although most specimens moved out of the medium by creeping up the aquaria. Specimens in the control seemed lively and unaffected by oiling throughout the duration of the experiment. Mortalities were as high as 117 out of 180 individuals during the entire experimental period, with higher concentrations recording higher mortalities. There was steady increase in mortality from 4 individuals in the first 24 hours to 12 individuals after 72 hours in the 150ml/l concentration. The LC 50 values were obtained by graphical interpolation. It is concluded that the soluble fraction of the Nigerian light crude oil could be detrimental to shellfish even at a concentration as low as 1000ml/l of the estuarine water.

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Effects of Simulated Oil Exposure on Two Intertidal Macrozoo Benthos: Tympanotonus fuscata (L) and Uca tangeri (Eydoux, 1935) in a Tropical Estuarine Ecosystem

Cited by 8 publications

References 0 publications

Studies on the short-term fffects of the mobil Idoho oil Spill on the Littoral Biota of Southeastern Nigeria

Studies on the short-term fffects of the mobil Idoho oil Spill on the Littoral Biota of Southeastern Nigeria

Impact Of Crude Oil On Recruitment Of Epibenthic Organisms In Cross River Estuary, South East Nigeria

Effects of crude oil on the gastropod, tympanotomus fuscata in the Cross River Estuary, south-east Nigeria

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