DailyCelestialChallenge Monday-Darkness. (Black Tide)

The oil slick is the oily mass that is created when there is a large oil spill or some of its derivatives in the marine environment. Its ecological effects can be felt for years, and depend on the type of discharge, the amount of it and the type of coast affected.

The oil slick causes the most damage when it reaches the coasts. The organisms most sensitive to this contamination are those that live fixed to the substrate or that have a reduced mobility, as is the case of algae and invertebrates, among which are molluscs, crustaceans, anemones, sponges and sea worms. To them we must add the eggs of many species.

The causes of mortality among the living beings that inhabit an area affected by a spill are the lack of light, a factor of great importance because it prevents the photosynthesis made by algae and supposes the beginning of the food chains in the ocean. Also suffocation, by preventing breathing, hunger for lack of food, paralysis when animals are immobilized, poisoning and cold, in the case of birds, which lose the ability to waterproof their feathers. To the ecological damages must be added the economic ones. The fishing sector and related industries, as well as tourism, can suffer considerable losses, which have an impact on the economy of the polluted region.

Discharges of oil and its derivatives begin to slowly degrade naturally when coming into contact with the marine environment. In this process, physical, chemical and biological factors act. Thus, for example, lighter components evaporate faster the higher the wind speed and temperature. Sunlight and oxygen cause chemical degradation of the spill and the heavier components are slowly decomposed by bacteria and fungi. It seems that the recovery of areas that have suffered large spills, depend on the type of coast and the prevailing waves. The most beaten areas record recoveries faster than those protected.