Images obtained from NASA’s Earth Observatory as recently as 19 March 2014 indicate what appears to be a huge build-up of sulfur in the ocean, expanding gradually along the shore to the south of Sandwich Harbour.
The latest images show that the sulfur eruptions cover an extensive part of the coastline.
The Earth Observatory confirms that hydrogen sulfide gas is highly toxic to fish and that the “periodic die-offs of whole populations of fish and other commercial seafood are ongoing concerns for the regional fishing industry”.
In his recent annual address on the state of the fishing stocks and the industry, Minister Bernhard Esau noted with concern that during the summer months of 2013, extensive regions of the sea were found to have low levels of oxygen, although he reported that the state of affairs with regard to oxygen depletion in the ocean had improved by mid-year.
The NASA scientists noted that the regular eruptions along the coast of Namibia occur mainly when bacteria release hydrogen sulfide gas, as they break down dead plants and animals that have sunk to the sea floor. As the gas rises to the surface, it interacts with oxygen to form solid white sulfur.
“Hydrogen sulfide eruptions happen frequently off the shore of Namibia , because of patterns in the ocean currents, called upwelling. Cold water pushes nutrients from the ocean floor to the surface, where large colonies of microscopic ocean plants, phytoplankton, grow in the nutrient rich water.
“As the plants use all of the nutrients in the water, they die and sink to the sea floor where bacteria consume them. The bacteria release toxic hydrogen sulfide gas into the soil. Eventually, the toxic gas erupts from the soil.” This is usually accompanied by massive fish die-offs and a stench that resembles rotten eggs.
A spokesperson for the ministry of fisheries said on Tuesday that they were not aware of the scale of the latest eruptions, but "clearly something [significant] is happening".
Mr Charles Matengu said that, after this newspaper alerted fisheries officials to the situation on Monday, they dispatched a team of marine scientists to investigate. The issue is receiving high-level attention, he said, as there are likely to be environmental impacts.
According to NASA Earth Observatory, hydrogen sulfide eruptions have only ever been observed off the shore of Namibia. The ministry is expected to provide a more detailed report on the situation later today (Tuesday).
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