New Marovo lagoon research uncovers reasons
WHEN a large number of fish mysteriously died and twice discovered on the coast of Marovo Lagoon some two years ago, villagers there were left wondering.
A Queensland University research carried out immediately after the discoveries pointed out the cause may be triggered by climate change.
However, a later research local scientist Dickson Boboria carried out within the waters of Marovo lagoon concluded the deaths were caused by heavy metals accumulation and high concentration in the sea shells.
MrBoboria published his findings in a new book entitled “Heavy metal in sediments and bivalves and nutrients in Marovo lagoon”.
MrBoboriatook extensive research on the topic since 2013.
“I check the sea sheets, no contaminants, checked the water column, still no contaminants, the lagoon can still cater to living organisms,” he said.
“I believe this is where the Queensland University research left.
“So I took other steps further, collecting samples from the sea shells (Bivalves).
“Here I found something unusual; there’s a higher concentration of the contaminants in them.
“The contaminants were accumulated in the bivalves because they were attracted to the carboxylic acid inside the bivalves.
“This is the reason why no contaminants were found in the water body.”
He said t the whole lagoon was carbon sink area.
“This means that any contaminants fell in to the lagoon got trapped in the sea shells and accumulated.”
Mr Boboria added that when he investigated this, two nutrients that existed in the lagoon were Nitrate and Phosphate – both were fertilizers.
“These fertilizers come from the forest. Then I found out that almost the whole of Marovo has been logged; exposing soil surface where these fertilizers were found.
“As a result, they were washed down into the lagoon with soil sediments.
“These two contribute to a process called algal bloom. When the fertilizers reached the lagoon, they fertilize algae and water grass to grow.
“After grass and algae growth, bacteria attacked and decayed them through another process called ethophication, a process that reduced oxygen level in the water as oxygen used up by bacteria.
“As the water lacks oxygen, it results in fish dying in large numbers.
“Maximum dissolved oxygen in the water should be 7-8miligram per liter; but in the case of Marovo Lagoon, it has been far less than the maximum.”
MrBoboria said that no poisonous elements were found in the dead fish due to lack of oxygen.
He further discovered that Marovo lagoon contained highly dangerous heavy metals in it.
“There are natural deposits of copper, but lead, chromium, and cadmium were human induced.
“These are too high due to use of fuel on engines, sewage dumping, medical wastes, mining exploration, lead batteries, paints, oil palm plantation, and submarine volcano.
“Contaminants concentrations in the lagoon were well above world standard, which is 1miligram per kilogram.”
“The hydro dynamic in the lagoon was so poor, meaning that the water exchange from the open sea to wash out the contaminants is not happening due to the double barrier reef of the lagoon.
“Wind does mixing at the top, but the bottom remains contaminated.”
He described the situation there as uncertain and dangerous, and that it’s impacts on people’s health will happen soon.
“The situation there is far more dangerous.
“I have predicted that in five to10 years’ time, the whole lagoon will no longer safe, and will have health impacts on human being.
“New born deforming, cancer, infertility, and other illness will be seen there.
“Marine life will be poisoned, as the whole food chain was contaminated and as people depend on the marine for livelihood, they will be affected.
He recommended the following:
– Logging must be stopped. If stopped, it will take 26 years for the whole marine ecosystem to recover.
– The whole of Marovo must be conserved as a marine protected area as it was potentially at risk.
– If people were to protect the heritage site, they must work together.
– People should venture into other commercial sectors like tourism.
By CHARLEY PIRINGI