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.

Roundup: Cyanobacteria, Glacier Calving and Glacier Fluctuations

Arctic biocrust cyanobacterial communities

Microcystins Souce: Flickr

“In the polar regions cyanobacteria are an important element of plant communities and represent the dominant group of primary producers. They commonly form thick highly diverse biological soil crusts that provide microhabitats for other organisms. Cyanobacteria are also producers of toxic secondary metabolites. The north-west coast of Spitsbergen, are able to synthesize toxins, especially microcystins and anatoxin-a. To the best of our knowledge, this is the first report on the presence of ANTX-a in the entire polar region. The occurrence of cyanotoxins can exert a long-term impact on organisms co-existing in biocrust communities and can have far-reaching consequences for the entire polar ecosystem.”

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Dynamics of Glacier Calving

Glacier Calving Source: Flickr

“During summer 2013 we installed a network of nineteen GPS nodes at the ungrounded margin of Helheim Glacier in south-east Greenland together with three cameras to study iceberg calving mechanisms… The glacier calved by a process of buoyancy-force-induced crevassing in which the ice downglacier of flexion zones rotates upwards because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone… “

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Reconstruction of glacier fluctuations

Reconstruction of glacier fluctuations Source: Flickr

“It is presented the results of study of bottom sediments of the proglacial lakes enriched with meltwater of Peretolchin Glacier, Chersky Glacier and glaciers of the Kodar Ridge. Bottom sediments were investigated with time resolution in year-season, using X-ray fluorescence. We have defined three periods in significant increase of glacier flow/melting during the last 210 years. The first period (ca. 1800–1890), supply of suspended material by meltwater into Lake Ekhoy and Lake Preobrazhenskoe, was not intense until 1850 and 1875, respectively. However, the rate of meltwater supply into Lake Izumrudnoe was high during the Little Ice Age, and it is likely attributed to local moisture from Lake Baikal. The regional glacier water balances were most likely positive during the second period (ca. 1890–1940). The third period (ca. 1940–till present) was characterised by moderate melting rate of glaciers located on the Kodar and Baikalsky Ridges, in contrast to Peretolchin Glacier that demonstrated the highest rate of melting and changes in outlines during this period.”

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