Anne Jungblut sampling biofilms on the McMurdo ice shelf

Anne Jungblut sampling biofilms on the McMurdo ice shelf

Blue-green algae from legendary Captain Scott expedition help study of climate change

Scientists have analysed 100-year-old blue-green algae collected during Captain Scott's famed RRS Discovery expedition and found the oldest examples of cyanobacterial toxins in Antarctica.

The new analysis is published in the European Journal of Phycology.

The team, led by Museum researcher Dr Anne Jungblut, set out to study the presence of cyanotoxins - toxins produced by cyanobacteria, more commonly known as blue-green algae.

Toxic algae can pose a major threat to freshwater ecology and human health, and often occur in temperate and tropical climates all over the world during the summer months.

A dried herbarium  specimen collected during Captain Scott’s Discovery Expedition

A dried herbarium  specimen collected during Captain Scott’s Discovery Expedition in December 1902. This is a sample of a microbial mats, layered structures of algae.

 

The samples the team worked on are the oldest of their kind, collected during Captain Scott's Discovery expedition to Antarctica between 1901 and 1904.

They were taken at a time when Antarctica which was largely unaffected by human activity - unlike the current landscape which could see warmer temperatures affecting the delicate ecosystem in the future.

Climate models predict that Antarctica will warm more rapidly than many other parts of the globe. And in Antarctica, it is especially important to study the impact of warming on freshwater ecosystems, as it holds 70% of the freshwater supplies on Earth.

Blue-green algae covering the floor of a meltwater pond on the McMurdo ice shelf in Antarctica.

Blue-green algae covering the floor of a meltwater pond on the McMurdo ice shelf in Antarctica. The ponds have liquid water in summer and freeze in winter. The environmental conditions are extreme and only microbial life can thrive in these unique Antarctic ecosystems. Image credit: Taylor & Francis

 

A new and crucial baseline

The samples provide an essential baseline for levels of cyanotoxins in Antarctic freshwater, prior to human activity. This discovery will enable scientists to determine the effects of climate change on blue-green algae and their toxins in Antarctica in the future.

It is the first time that a research group has reported finding the toxin β-Methylamino-L-alanine (BMAA) in Antarctica, which has been linked to diseases that affect the brain and nervous system.

The role of BMAA in Antarctic benthic ecosystems is not yet known.

Dr Anne Jungblut says, 'Our work expands the knowledge on the biogeographic distribution of the toxin.

'The results will be new baseline data from the onset of human activity in Antarctica, the ozone hole and current levels of climate change.

'Currently toxin levels are low in Antarctica, but the potential introduction of alien cyanobacteria and warming temperatures could increase toxin levels in the future.'

The McMurdo ice shelf in Antarctica, where some of the specimens were collected

The McMurdo ice shelf in Antarctica, where some of the specimens were collected

 

Researchers also found a toxin called microcystin in the samples. Microcystin is a liver toxin and has been found in Antarctica before, but these samples are the oldest ones to date.

In the long term, microcystin could affect biological diversity in freshwater ecosystems, although it is unlikely to impact human health.

Historic samples from a famous voyage

British explorer Captain Scott led two expeditions to the Antarctic, the Discovery expedition (1901-4) and the later ill-fated Terra Nova trip (1910-13).

Discovery was one of the first to explore the Antarctic region and resulted in many breakthroughs in the fields of biology, zoology and geology.

One of the cyanobacteria specimens collected on the McMurdo ice shelf

One of the cyanobacteria specimens collected on the McMurdo ice shelf during Captain Scott’s Discovery Expedition in December 1902

 

A large collection of specimens was made during the two-year stay on Ross Island, Eastern Antarctica, many of which were deposited at the Museum, including the samples of freshwater cyanobacterial mats used in this study. The six samples come from two locations, the first is Ross island, where Scott had winter quarters, and the second is the McMurdo ice shelf.

As new analytical advances are made, such as those used in this study, the ongoing importance of the voyage in tackling current science challenges in Antarctica is increasingly evident.

It is likely there will be many more discoveries made from this historic collection of samples.

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