Carbon incursion may have caused deaths

THE dying of fish at Wosera-Gawi in East Sepik maybe due to carbon incursion.
Freshwater has two main layers, photic zone and profundal.
The photic zone comprises littoral and limnetic zones which are top layers and are high in oxygen content where most fish and aquatic plants are found.
The profundal zone is a zone below the photic zone where most dwellers there are scavengers and predators, for example; crustaceans, crabs, fish such as eels and glossogobius.
These animals usually feed on dead animals that settle down.
This region is very turbid (high content of dissolved materials) and has less oxygen content (depleted oxygen).
The pH in the Profundal region is usually low (acidic) due to the presence of excessive carbon dioxide.
The carbon incursion usually happens during heavy rain after a prolonged dry season.
This is because during the dry season, the input of oxygen at the above layer (profundal region) is less as warm water cannot hold more oxygen due to the increasing temperature.
Since the dissolved rate of oxygen is inversely proportional to the temperature.
When this happens, the bottom layer wants to be in equilibrium with the above layer and during the heavy rain, the layers are swapping, hence, making any oxygen-sensitive organisms such as fish, especially catfish die because oxygen is a very critical requirement for respiration.
A similar incident happened in Morobe, in the Markham River in 2012, which was devastating.

David Maima Iarume (UOG)