New Cyanotoxins Surface in Polar Region
This year’s Climate and Society class is out in the field (or lab or office) completing a summer internship or thesis. They’ll be documenting their experiences one blog post at a time. Read on to see what they’re up to.
By Yunziyi Lang, C+S ’15
Death by cyanobacteria-made microtoxins is not pleasant. The toxins could damage the nervous system, especially anatoxin-a, also known as a Very Fast Death Factor.
As the global temperature increases, concerns about the range of these toxins are growing. For the first time, anatoxin-a has been found as far north as the polar region, according to a new paper published by Ewelina Chrapusta, a PhD candidate in molecular biology at Jagiellonian University in Krakow, Poland, and her colleagues. They revealed that biocrust-forming cyanobacteria from the Kaffiøyra Plain, located in the northwest coast of Spitsbergen, are capable of synthesizing toxins, specifically microcystins and anatoxin-a.
Working as a writer at GlacierHub, a website dedicated to expanding and deepening the understanding of glaciers and raise awareness of climate change, I am particularly interested in covering scientific and community-based topics related to mountain glaciers. Retreat of glaciers plays a vital role in affecting regional water availability, agricultural output and volcanic eruptions. In addition, glacier meltwater will most likely alter physical and chemical features of aquatic ecosystems.
Research has shown that global climate change is anticipated to lead to the rapid development of hazardous cyanobacterial species with “increasing growth rate, dominance, persistence, geographical distribution, and activity.” In fact, ice melting in the Arctic regions will provide relatively suitable habitats for cyanobacteria and could lead to higher production of cyanobacterial toxins.
Microcystins and anatoxin-a are produced by freshwater cyanobacteria. Their high toxicity makes them a serious threat to other organisms, including livestock and humans. These toxins act extremely rapidly and could cause death in minutes or hours, depending on the dose.
In 1996, the first outbreak of cyanobacterial toxins poisoning occurred in Caruaru, Brazil, killing 76 patients from liver failure. Another episode happened in Brazil in 2000, which involved 2000 cases of stomach flu and 88 fatalities within roughly 40 days. These toxins are recognized as secondary metabolites. They allow the cyanobacteria to flourish under nutrient-rich conditions and reproduce exponentially.
Cyanobacteria are the most significant component of microbial and plant communities, especially in polar ecosystems, because they can provide microhabitats for other organisms. Specifically, they create a cohesive and diverse biocrust on moist soils and in freshwater reservoirs of nutrient-poor habitats, especially glacial moraines. The biocrust serves as shelter for a variety of organisms, including rotifers, fungi, green algae and viruses. Even though the ability of cyanobacteria to synthesize toxins has been well demonstrated in low latitude locations, the “production of toxins in high latitudes is largely unexplored,” according to Chrapusta.
As a consequence of global warming, increased frequency of cyanobacterial blooms pose severe threats to human health in communities worldwide, especially those that rely on glacial meltwater to live in polar regions. Chronic exposure to cyanobacterial toxins in humans could increase the risk of organ damage, which may develop into cancer.
More research is needed to fully understand the extent to which rising global temperatures will influence cyanobacteria populations and their ability to produce toxins in the future. Moreover, specific species of cyanobacteria, which combine microcystins and anatoxin-a, need to be identified so that the distribution of such toxins could be monitored and projected accurately. In any case, the detection of anatoxin-a at high latitudes is a serious warning sign of possible dangers that may come in the future.