Humboldtians in Focus

The Life of Antarctica

By Kristina Güroff

In summer the temperatures at the warmest points in Antarctica hover around zero. For two to six months, one percent of the ground may be snow-free – not much time for the Argentine scientist, Cecilia Flocco, to collect the flowering plants, roots attached, that grow in this extreme environment.

 
Humans do not have protective
suits like penguins: Cecilia
Flocco in the field.
Foto: E. Hernández

Plants affect the soil mainly by the substances they release via the roots: this area of but a few millimetres around the roots is known as the rhizosphere. It is here that the soil interacts with the plants creating an important environment for microorganisms such as archaea, bacteria and fungi. The Argentine biochemist and pharmacist, Cecilia Flocco, wants to discover if and how the microbial life of the rhizosphere is influenced by Antarctic conditions. To this end she is examining the only two indigenous species of seed plant to grow there, if only in the warmest, most northerly parts of the Antarctic Peninsula: the Antarctic hair grass, part of the Gramineae family, and the Antarctic pearlwort, which belongs to the carnation family. The rest of the vegetation in Antarctica is made up of lichens and mosses.

In 2004, when she was a researcher at the Instituto Antártico Argentino (Microbiology Group, Dr. Walter P. Mac Cormack), Cecilia Flocco was granted one of the sought-after places at the permanent Argentine research station Jubany. The station is situated on King George Island, the largest of the South Shetland Islands, between South America and the coast of the Antarctic continent, 120 kilometres away. While working on the Antarctic expedition, the scientist was able to take samples from five different locations.

She wants to use gene analysis to investigate the composition of the microbial communities and the strategies used by the plants and their associated microorganisms in the root area to survive under extreme conditions. She also wants to know whether and how they have adapted to environmental pollution and which genes are responsible for this. Perhaps, in the long term, microorganisms could contribute to the degradation of oil pollution even in Antarctica.

“Not even Antarctica can escape the noise and ecological pollution caused by research stations and tourists.”

Antarctica is the only place where such unique ecosystems can be investigated. Its distance from other land masses and ocean currents protect the continent from the influence of other ecosystems. Due to the extreme environmental conditions and the protection provided by the Antarctic Treaty and the Environmental Protocol the region is still largely free of human influence. Largely – because anywhere where people settle, they leave traces. There are now some 40 permanently manned research stations and regular tourist expeditions with all the concomitant foodstuffs, equipment, energy and fuel, and – despite taking every care – they produce noise and ecological pollution.

 
Affect the microorganisms around
their roots: Antarctic pearlwort,
pearlwort with roots, Antarctic
hair grass (from left to right).
Foto: Cecilia Gabriela Flocco

The samples taken from the soil around the Jubany station, for example, revealed slight but measurable polycyclic aromatic hydrocarbon pollution. Many of these organic compounds cause cancer. They are a natural component of oil and can be found in heating oil, fuel and so on. They find their way into the ground both directly and indirectly via the air as a consequence of emissions. Continued warming could mean that increased precipitation and receding glaciers cause more pollutants to be flushed out of the ground into the water – with unforeseeable results for the local ecosystem. Can anything be done about it and, if so, can it be reconciled with the strict regulations governing Antarctica?

Biological degradation of pollutants

Flocco’s basic insights into the microbial life of Antarctica could prove important for potential biological degradation of soil pollutants because the metabolism of microorganisms means that complex molecules are degraded into simple ones during detoxification or energy production, an aspect of interest to researchers in connection with soil and water decontamination applications. Cecilia Flocco’s PhD thesis in biotechnology already dealt with the targeted use of plants to degrade pollutants in soil. As introducing foreign organisms or species into Antarctica is not allowed, Flocco wants to examine whether there is a long-term option to decontaminate the soil by using the catabolic pathways, i.e., the metabolic functions of indigenous microorganisms and plants. In order to break the long carbon chains of oil and the more complex polycyclical aromatic hydrocarbons, microbes utilise certain enzymes. The scientist wants to track down the genes that determine these enzymes and discover whether they proliferate differently in clean and polluted samples.

 
Oil tanks at Jubany station.
Foto: Cecilia Gabriela Flocco

However, after the Antarctic expedition the project had to be put “on ice” until Cecilia Flocco was granted a Humboldt Research Fellowship at the Federal Research Centre for Cultivated Plants in Braunschweig (Working group: Professor Dr. Kornelia Smalla) where she found the technical prerequisites she needed for her molecular biological investigations.

She was able to show that the microbial community in the rhizosphere of both plants was different from that in the rest of the soil, findings that have often been observed outside Antarctic conditions, too. Her analyses also revealed the presence of genes in the Antarctic soil samples which code enzymes for degrading oil. In the polluted samples she discovered more genes of a certain type that are associated with degrading pollutants than she did in the unpolluted samples. One of the results of the gene analyses was to determine exactly which genes were common in the microorganisms to be found in the soil at the locations around the Jubany station. The next step will be to determine the respective enzymes. In order to develop targeted strategies for potential natural soil cleaning it is decisive to know which genes and enzymes are involved in degrading polycyclical aromatic hydrocarbons at a given site. Cecilia Flocco will be continuing her research in this field.


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Cecilia Gabriela Flocco Cecilia Gabriela Flocco

Dr. Cecilia Gabriela Flocco taught and conducted research at the Department of Pharmacy and Biochemistry at the University of Buenos Aires in Argentina before becoming a Humboldt Research Fellow at the Federal Research Centre for Cultivated Plants – Julius Kühn-Institute, in Braunschweig until 2008.

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