Tarballs

In news– Several beaches in Mumbai and Goa witnessed black oil-emanating balls/ Tarballs(sticky tarballs with foul fuel smell) lying on the shore.

What are tarballs?

They are dark-coloured, sticky balls of oil that form when crude oil floats on the ocean surface.
A tarball is a blob of petroleum which has been weathered after floating in the ocean.
Tarballs are formed by weathering of crude oil in marine environments.
They are transported from the open sea to the shores by sea currents and waves.
Tarballs are usually coin-sized and are found strewn on the beaches.
However, over the years, they have become as big as basketballs and can weigh as much as 6-7 kgs.
Most of the time, the presence of several tarballs indicate an oil spill.
In India, Tarballs reach the western coast during the monsoon.
According to the National Institute of Oceanography (NIO), wind and waves tear the oil slick into smaller patches that are scattered over a much wider area and various physical, chemical and biological processes (weathering) change the appearance of the oil.
It is suspected that the oil comes from the large cargo ships in the deep sea and gets pushed to the shore as tarballs during monsoon due to wind speed and direction.
The tarballs that travel towards the coast can get stuck to the fishing nets installed in the sea, making it difficult for fishermen to clean.
In addition, it could affect marine life, especially filter feeders like clams and oysters.
Microbes such as bacteria and fungi presumably play an important role in tarball degradation.