A fungal bloom in Australia’s coastal waters has been connected to the massive dust storm that started in Lake Eyre Basin and shrouded the entire east coast in 2009. Marine scientists have described the bloom as a ‘rare, ‘accidental’, and ‘serendipitous’ finding.
“This fungus is essentially a terrestrial organism that is extremely tolerant to salt, and this is rare,” according to Australia’s expert on phytoplankton Professor Gustaaf Hallegraeff from the Institute for Marine and Antarctic Studies, University of Tasmania.
In 2009, after 10 years of drought, a cold front swept up about 16 million tonnes of dust from the deserts of Central Australia, and winds in excess of 100 km an hour spurred the massive dust storm—measuring about 500km wide and 5,500km long—to sweep across eastern Australia. An estimated 75,000 tonnes of the dust crossed the coastline and was recorded as far east as New Zealand. In his research findings to be published in June, Professor Hallegraeff suggests that Great Barrier Reef corals and other marine life could be susceptible to disease if more pathogenic strains of fungi develop from future dust storms.
“Dust that originates in deserts is well known to be a vehicle for the spread of microbial communities, and a concern for accidental spread of contaminants and diseases,” he said.
The stroke of serendipity was that Australia’s Integrated Marine Observing System (IMOS) started collecting plankton biodiversity data using a Continuous Plankton Recorder (CPR) a year before the dust storm. IMOS has developed the first long-term plankton baseline for Australian waters. The CPR was sampling the plankton in the water between Brisbane and Sydney about 3 weeks after the dust storm.
“So we unexpectedly collected massive concentrations of black fungal spores about 30km offshore just after the storm,” said Professor Hallegraeff.
The black ‘oil-looking substance’ that was collected and preserved in formalin for study, was also used to later culture the organism in the laboratory. CSIRO marine scientist and University of Queensland Associate Professor Anthony J. Richardson, who leads the CPR survey for IMOS, is particularly interested in how the fungi survives formalin.
“This is sort of unheard of – formalin is supposed to kill everything.” Both Richardson and Hallegraeff hadn’t seen anything like the ocean fungal bloom before the 2009 storm, nor have they seen anything like it since.
“Imagine that a lot of this [fungi] is going to grow in the marine environment, and that it is going to do something different there – it is going to produce different chemicals compared to how it behaves on the land,” Hallegraeff proposed.
“This is where we are at right now, trying to understand these fungal toxins. Fungal impacts have been well documented in terms of human health and agriculture, but broader impacts on marine impacts remain undocumented.”
The scientists are particularly eager to understand the fungus in the light of climate change, as projections suggest extended dry periods, and hence increased potential for dust storms. Their initial research found no soft coral disease outbreak as a result of the fungal bloom, but a number of questions remain. How could this fungus affect fish? How could it affect corals? How does it affect algae (including the symbionts that support the coral)? Is there the potential for it to affect humans? We know that some fungal toxins may accumulate in filter feeders such as molluscs and oysters. So does that mean the fungus could reach the human food chain?
“We have no evidence yet. But now we are aware of it, we can watch for it,” Professor Hallegraeff said. “The IMOS plankton survey will enable this kind of exciting research into the future. It highlights the value of sustained ocean observing for studying these unexpected events.”
IMOS is a national collaborative research infrastructure, supported by Australian Government. It is led by University of Tasmania in partnership with the Australian marine and climate science community.
For more information about IMOS please visit the website www.imos.org.au
Professor Gustaaf Hallegraeff Institute for Marine and Antarctic Studies, University of Tasmania Phone: +61 3 6226 2623, Email: Hallegraeff(at)utas.edu.au
Associate Professor Anthony J. Richardson CSIRO Marine and Atmospheric Research and University of Queensland Phone: +61 7 3826 7183, Email: Anthony.Richardson(at)csiro.au
Images for use under Creative Commons, with attribution:
For media assistance
Marian Wiltshire, Communications Manager Integrated Marine Observing System, Hobart, Tasmania Phone: +61 3 6226 7505, Email: Marian.Wiltshire(at)utas.edu.au
Sydney Harbour bridge: image taken from Wikipedia [http://commons.wikimedia.org/wiki/File:Sydney_harbour_bridge_duststorm.jpg] [published under a Creative Commons license]
Dust storm map adapted from Wikipedia [http://en.wikipedia.org/wiki/File:2009_Dust_Storm_-_Australia_and_New_Zealand_Map.png] [published under a Creative Commons license]
Abundance diagram: image taken from Integrated Marine Observing System. 2011. AusCPR Newsletter, no. 2, p 3–4. Integrated Marine Observing System, Hobart, Tasmania. http://imos.org.au/uploads/media/AusCPR_newsletter_No.2_April2011.pdf.