Heavy metal pollution in Antarctica and its potential impacts on algae

Antarctica is not free from environmental pollutants although it is often perceived as the last pristine continent on Earth. Research stations represent one of the largest forms of anthropogenic activity and are the main source of locally derived contamination in Antarctica. Elevated levels of heavy metals such as copper (Cu), lead (Pb) and mercury (Hg) have been detected in Antarctica. Fuel combustion, accidental oil spills, waste incineration and sewage disposal are amongst the primary sources of heavy metal contaminants in Antarctica, besides natural sources such as animal excrements and volcanism. Studies on the impacts of heavy metals on biota in Antarctica have been focused mainly on invertebrates and cryptogams but not on algae. However, adverse impacts of heavy metals on sensitive algae may affect organisms at the higher trophic levels, and consequently disrupt Antarctic food chains. Heavy metals may be accumulated by algae and biomagnified through the food chain. The sensitivity and response of Antarctic algae to heavy metal toxicity have not been well studied. Robust toxicity protocols for the testing of the impacts of heavy metals on Antarctic algae need to be developed. This review aims to give an overview of the status of heavy metal pollution in Antarctica and its potential impacts on algae

Influence of heavy metals on the occurrence of Antarctic soil microalgae

Human- and animal-impacted sites in Antarctica can be contaminated with heavy metals, as well as areas influenced by underlying geology and naturally occurring minerals. The present study examined the relationship between heavy metal presence and soil microalgal occurrence across a range of human-impacted and undisturbed locations on Signy Island. Microalgae were identified based on cultures that developed after inoculation into an enriched medium. Twenty-nine microalgae representing Cyanobacteria, Bacillariophyta, Chlorophyta and Tribophyta were identified. High levels of As, Ca, Cd, Cu and Zn were detected in Gourlay Peninsula and North Point, both locations hosting dense penguin rookeries. Samples from Berntsen Point, the location of most intense human activity both today and historically, contained high levels of Pb. The contamination factor and pollution load index confirmed that the former locations were polluted by Cd, Cu and Zn, with these being of marine biogenic origin. Variation in the microalgal community was significantly correlated with concentrations of Mn, Ca, Mg, Fe, Zn, Cd, Co, Cr and Cu. However, the overall proportion of the total variation contributed by all metals was low (16.11%). Other factors not measured in this study are likely to underlie the majority of the observed variation in microalgal community composition between sampling locations