Oil Spill in a Marine Environment

1. With six larger fuel oil spills (> 700 tonnes) and with four medium fuel oil spills (7 – 700 tonnes) recorded in 2024 from tanker incidents (with nearly 8 large oil spills per annum with the recent decade), and with the total volume of oil lost from tanker spills in 2024 amounting to nearly 10,000 tonnes, why do we have an increase in tanker spills particularly from 2019 (when the growth in crude and other tanker trade loaded started declining)?

2. In the context of ‘causes of tanker spills’, why do we have an enhanced failure resulting from allisions/collisions (30%) as well as from grounding (31%) rather than predominantly from hull failure (13%) or from equipment failure (4%) or from fire/explosion (11%)?

3. Accidental spills from tankers account for only a small percentage of the oil that enters the oceans each year?

Does it not include the contributions from pipeline spills, oil industries, oil spills from non-tankers and other natural seepages?

4. Whether the simulation of oil spill trajectories towards oil spill modelling remain controlled only by hydrodynamics and wind forcing?

5. Upon oil getting spilled into ocean (even, if we get to know the details on the exact location and depth of the oil spill, the type of the oil spilled and the exact volume of the oil spilled), feasible to clearly distinguish the overlapping and intersecting of oil weathering (that refers to oil spreading, evaporation, emulsification and natural dispersion followed by dissolution, photo-oxidation, biodegradation and sedimentation; and which alters the physico-chemical properties of the spilled oil @ different time levels and with varying rates) and transport (that increases the size of the oil spill contamination area) – towards oil spill contingency planning and coastal management?

6. How do we conclude, whether, a significant portion of the spilled oil into a marine environment has gotten dispersed into the water column as oil droplets?

OR

Transport and fate of a spilled oil must always accompany the formation, settling and transport of oil-mineral-aggregate?

7. How easy would it remain to capture the slick over the water surface from the spilled oil resulting from gravityand oil-water IFT?

8. Do we require the details on tidal streams, water currents as well as wind speeds (apart from oil properties and coastlines) towards estimating the spreading rate of spilled oil?

Even then, can we precisely forecast oil advection @ sea surface and oil advection into the water column?

If so, then, should we go ahead with a 3D model towards tracking the spilled oil @ surface and in the water-column (and not a 2D model that only simulates the trajectory of the spilled oil @ water-surface)?

9. Whether microbial mucus production (flocculent material observed in surface waters that contains significant fossil carbon) could play a significant role following an oil spill?

If so, then, Marine Oil Snow Sedimentation and Flocculent Accumulation (MOSSFA) could also act as a potential pathway for oil distribution in marine environment (on top of oil spill response planning)?

But, how do we have a control over the release of exopolymers by bacteria and phytoplankton (that depends on local conditions involving light, UV, temperature, weathering and minerals characterized by a multitude of drivers spanning from molecular-scale to organismal-scale), which remain to be an essential ingredient for marine snow as well as for marine oil snow?

10. What exactly promotes the microbial degradation of oil compounds (the way microbes respond to oil)?

Dr Suresh Kumar Govindarajan

Professor [HAG]

IIT Madras

25-Jan-2025