Toxic aquatic bacteria on the increase due to climate change

Global warming could mean the proliferation of toxic cyanobacteria, putting human and animal health in danger, according to scientists. It has been noted that cyanobacteria populations have been increasing significantly in recent years, especially in warmer summer months, but this could be a precursor to further increases.

Cyanobacteria are primitive aquatic organisms, which have lived on earth for three and a half billion years. They favour warmer waters and in some cases produce toxins that are harmful to other animals. We do however, owe these organisms much, as they are the likely cause for the early oxygenation of our atmosphere, allowing more advanced life to develop.

The basis for the scientist’s theory is that global warming will increase ocean temperatures, fuelling the growth of these cyanobacteria populations. Unfortunately they cause a number of problems; the blooms are becoming common in some oceans of the world and can affect shipping, tourism, water sanitation and impact on local wildlife. It has already been shown that the cyanobacteria are responsible for higher death rates of wild fauna.

Francisca de Campo, who co-authored the research says, "These toxins may affect the liver and other organs (hepatotoxins), the nervous system (neurotoxins), different cells (cytotoxins), the eyes and mucous membranes, as well as causing dermatitis and allergies."

The problem is becoming more urgent in warmer countries. Research in Spain for example shows that 20 per cent of reservoirs have more than the guide level of cyanobacteria dictated by the WHO for bathing water quality. Of those nearly half have greater than the recommended WHO level of microcystins, which damage the liver.

Scientists are now pushing urgently for action on this subject, which has been largely overlooked despite the serious health implications. "We suspect that these cytotoxins may be behind some gastrointestinal disorders and other illnesses, but epidemiological studies are required to confirm this,"