Killifish (Fundulus heteroclitus) and amphipods (Gammarus oceanicus) were exposed separately to either a No. 2 fuel oil, AP dispersant, or emulsions of the two in a static system. Both species exhibited a concentration-dependent response to all three treatments. However, emulsification of oil with dispersant clearly increased its lethal effect on killifish survival, but did not cause a differen...

When oil is mixed with light alkanes, asphaltenes can precipitate out of oil solutions in a multistep process that involves the formation of nano and colloidal scale particles, the aggregation of asphaltene colloids, and their eventual sedimentation. Amphiphilic dispersants can greatly affect this process. The mechanism of the dispersant action in colloidal asphaltene suspensions in heptane has...

Oil dispersants, the tool of choice for treating oil spills in tropical marine environments, is potentially harmful to marine life, including reef corals. In a previous study, we found that dispersed oil and oil dispersants are harmful to soft and hard coral species at early life stages. In this broader study, we employed a "nubbin assay" on more than 10 000 coral fragments to evaluate the shor...

The aim of this study was to evaluate the effects of chemically dispersed oil on an economically and ecologically important species inhabiting coasts and estuaries, the Pacific oyster Crassostrea gigas. Studies were carried out with juveniles, known to generally be more sensitive to environmental stress than adults. A set of enzyme activities involved in immune defence mechanisms and detoxifica...

laboratory-scale experiments were conducted to evaluate the joint action toxicity and biochemicaleffects of sublethal concentrations of forcados light crude oil (flco) and three dispersants against clariasgariepinus over a period of 28 days. the derived 96hrlc50 values revealed that the dispersant, ds/tt/066(0.03ml/l) was the most toxic, followed by dispersant, oc/tt/osi (0.19ml/l), flco (5.06m...

Suspensions of carbon black in oil, stabilized with adsorbed polyisobutylene succinimide (PIBSI) dispersant, are commonly used as model systems for investigating the soot-handling characteristics of motor oils. The structure of the carbon-black agglomerates changes dramatically with temperature; this results in a concomitant change in the suspension rheology. Linear and nonlinear rheological ex...

In this study we report the formation of marine oil snow (MOS), its associated microbial community, the factors influencing its formation, and the microbial response to crude oil in surface waters of the Faroe-Shetland Channel (FSC). The FSC is a subarctic region that is hydrodynamically complex located in the northeast Atlantic where oil extraction is currently occurring and where exploration ...

During the Deepwater Horizon incident, crude oil flowed into the Gulf of Mexico from 1522 m underwater. In an effort to prevent the oil from rising to the surface, synthetic dispersants were applied at the wellhead. However, uncertainties in the formation of oil droplets and difficulties in measuring their size in the water column, complicated further assessment of the potential effect of the d...

Low hydrocarbon concentrations stimulated the growth of Tetraselmis suecica, whereas higher concentrations (200 ppm) inhibited growth. The content of chlorophyll a in this microalga was affected in a similar way. Crude oil had the most marked effects. Dispersant SEAKLIN-101-NT and mixtures of oil and SEAKLIN-101-NT did not show selective toxicity for the microalga, although inhibitory effects c...

The aquatic organisms toxicity testing protocols developed by the chemical response to oil spills: Ecological Research Forum (CROSERF) were evaluated for applicability to assessing chemical dispersant toxicity under subarctic conditions. CROSERF participants developed aquatic toxicity testing protocols with the foremost objective of standardizing test methods and reducing inter-laboratory varia...