New Cyanotoxins Surface in Polar Region

Yellowstone National Park (Source: Kyla Duhamel/Flickr)
Scientists found that cyanobacteria live in hot springs in Yellowstone National Park. They convert nitrogen gas to nitrogenous compounds after sunset for their cell growth. (Source: Kyla Duhamel/Flickr)

Death by cyanobacteria-made microtoxins is not pleasant. The toxins 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 regions, according to a new paper by Ewelina Chrapusta, a PhD candidate in molecular biology at Jagiellonian University, in Krakow, Poland, and her colleagues. They revealed that some cyanobacteria were capable of combining different types of toxins, in particular microcystins and anatoxin-a.

Source: Roger Bunting/Flickr
Source: Roger Bunting/Flickr

According to G. Zanchett and E.C. Oliveira-Filho, 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 particular, glacier melt will provide more suitable habitats for cyanobacteria and lead to higher production of cyanobacterial toxins in the polar region.

Microcystins and anatoxin-a are produced by freshwater cyanobacteria. Their high toxicity makes them a serious threat to other organisms, including livestock and humans. According to J. Patockaa and L. Stredab, these toxins act extremely rapidly and could cause death in minutes or hours, depending on the dose.

Source: Christopher Sessums/Flickr
Source: Christopher Sessums/Flickr

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 biocrusts 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 crust-forming cyanobacteria to produce toxins has been well demonstrated in temperate and tropical regions, the “ecological role of cyanotoxins in polar ecosystems is poorly understood,” according to Chrapusta.

Source: Anita Gould/Flickr
Source: Anita Gould/Flickr

As a result of global warming, increased frequency of cyanobacterial blooms pose severe threats to human health in communities worldwide, especially those that rely on glacier melt-water to live. 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.

Photo Friday: Cryoconites and Glacier Tables

Have you ever seen dark cavities on glaciers, which are also referred to as “cryoconites”? These holes, which can be meters deep,are created from debris on top of glaciers. Dark-colored debris, including soot, dust, and pollen, speed up the melting process of glacial ice as a consequence of their low reflectivity to incoming sunlight. In some cases, glacial surface debris can also form pits in the ice through chemical melting. Hence, most of the glacial thaw holes are filled with melt-water, which become home to cyanobacteria, fungi, and other microbes. However, some large solid debris, in particular boulders, will prevent the ice beneath from melting as surrounding ice, forming glacier tables. Here are some photographs of cryoconites and glacier tables.

Learn more about glacial surface debris here.

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