The oil spill that the Mauritius coast suffered from had extended to a diameter of 15km making up a volume of 350km squared of their shore. The reason for such a large media coverage is due to the incorporation of many environmentally sensitive habitats and had been protected under the Ramsar Convention Wetlands of International importance as a biodiversity hotspot.
The immediate impact of the spill isn't the concern but it will effect the ecosystem equally where for example, pressures will be put onto the coral species causing the zooxanthellae to expel which is responsible for the photosynthesizing of the corals and this pressure is known as coral bleaching. This will then put significant pressures along the levels of the trophic cascade where these corals are often involved in a bottom up ecosystem.
A big issue with oil spills in marine environments is the addition of currents which drags the oil to which was transporting the oil to more environmentally important habitats composed of seagrasses, corals, mangroves. providing shelter, food source, nurseries, wave control. Although, a small area had been initially exposed to the oil, the nature of our marine systems had resulted in long term, long spanning areas. Larger
The initial impact of this spill was poisoning of much of the fish biomass reducing the population of many species within the 15km diameter and the vegetation will have withered and died. The first group effected had been the filter feeders including molluscs, crustaceans etc. There has yet been all the deaths resulting from the oil spill expected and will have long spanning effects for decades to come.
Corals take from 9-12 years to recover, however, due to significant declines of the herbiverous fish groom the corals to prevent coral bleaching and the consumption of older corals allows for the establishment of newer coral species. What is likely to occur is that algal turf will dominate the habitat, outcompeting all other aquatic flora. Larger grazing fish are likely to increase due to increase algal turf biomass, which will then in turn reduce energy transferred between the substrate and the fauna. It will then transfer energy between grazers to carnivores. Even with no effect on the fish population, it is highly likely that these corals would never return as they are known not to be profficient reproducers.
The oil spill has eradicated much of the light availability reaching the flora causing further light dependent species to simply wither and die. The soluble compounds from oil spills will then disolve in the water creating creating heavy residue onto the seabed preventing the establishment of aquatic floral species.
As hundreds to thousands of fish wash up onto our shorelines, the seabirds are also effected due to a lack of viable food source but as well, the oil weighs them down preventing them from flying where they will die of starvation/ exhaustion.
Although, a small area had been initially exposed to the oil, the nature of our marine systems had resulted in long term, long spanning areas. Shell are planning on leaving 4 abandoned platforms storing 11,000 tonnes of oil in the North Sea. Mauritius has just been a warning, due to increased wave velocities and more oil will potentially do untold damage for our marine systems and will have global consequences for many decades to come.
We never asked for a Mauritius part 2, so please spread the word and sign the petition below.
https://www.change.org/p/shell-stop-shell-north-sea-revolution?redirect=false
