A University of Queensland researcher is studying the use of algae and sea grasses as potential biological indicators of the health of the Great Barrier Reef.
Paul Bird, a Botany Department PhD student at the University's Heron Island Research Station, near Gladstone, believes marine plants provide the first warning signals for problems resulting from mainland runoff.
'Plants are among the first species affected by water enrichment from downstream nutrients into the Great Barrier Reef lagoon,' he said.
'My project uses marine plant responses to increased nutrient loads as an alternative to studying nutrients in the water column itself.
'It is estimated that 15 million tonnes of sediment are carried down rivers each year into the Great Barrier Reef, including 77,000 tonnes of nitrogen and 11,000 tonnes phosphates.
'About 80 percent of nutrients entering the reef are from grazing, 15 percent sugar cane cultivation, and one percent from sewage, all potentially affecting the reef ecology. '
Mr Bird's work provides a Great Barrier Reef comparison sample to the $2 million Brisbane River and Moreton Bay Wastewater Management Study - one of Australia's biggest and more significant environmental studies. The University of Queensland is the scientific manager for this study expected to lead to a comprehensive water quality strategy by mid-1998.
Mr Bird's work is being supervised by Dr Bill Dennison (University Botany Department), Dr Richard Lewis (University Centre for Drug Design and Development and Department of Primary Industries) and Associate Professor Gustaf Hallegraeff (University of Tasmania).
The study covers a 110km transect of the Great Barrier Reef from the mouth of the Fitzroy River back to Heron Island.
A major research component supported by the Great Barrier Reef Marine Park Authority is identifying whether the repeated release of slow dispersal nutrients within the different reef environments affects population densities of ciguatera-causing marine organisms living on algae and sediments.
Ciguatera is a chemical food-borne disease resulting from eating fish from toxic coral reefs. Toxins originate from a suite of tiny creatures known as dinoflagellates, found attached to a number of different host algae. The main culprit appears to be Gambierdiscus toxicus.
Scientists believe ciguatoxins enter the marine food chain from dinoflagellates attached to algae which are then eaten by herbivorous fish and benthic invertebrates.
Outbreaks of ciguatera disease are common along large portions of the Queensland coast. The largest ciguatera problem in Australia is in the Bowen to Port Douglas region with an estimated annual incidence of three cases per 10,000.
Symptoms manifest within 6-24 hours of consuming fish contaminated with a class of highly potent ciguatoxins.
They can include nausea and vomiting, aching joints, muscle pains, weakness, itching sensations and tingling and numbness of the lips, hands and feet. Some victims can experience 'temperature reversal', where cold objects give a burning or dry ice sensation. The most severe form of poisoning can result in cardiac failure.
Mr Bird said the only known treatment was an inert sugar, mannitol, when administered intravenously to patients receiving early diagnosis.
'However, up to 80 percent of cases of ciguatera poisoning go unrecognised, misdiagnosed or unreported,' Mr Bird said.
'The evidence appears to indicate that both natural and man-man disturbances to the reef can have a positive effect on dinoflagellate population densities.'
He said it was thought ecological triggers could develop 'superstrains' of extremely toxic populations. Researchers believed affected reefs could remain toxic for at least 50 years.
'Anecdotal evidence has linked these blooms to degradation following the blasting of reef channels; dredging; tourists walking on reefs; and nutrient increases,' he said.
'In my masters research I identified all the major, and some minor species of dinoflagellates linked to ciguatera disease in the Orpheus Island region of the Great Barrier Reef.
'Currently, this project is extending Brisbane River and Moreton Bay studies to the fringing reef of Heron Island and a biologically similar area on the unvisited Wistari reef. The work will also have potential in sustainable management of reef-related tourism.'
Mr Bird has optimised a method to estimate the population dynamics of sample algae and waste organics and to estimate dinoflagellate availabilities in the marine environment.
Part of his ongoing research will isolate and culture both the ciguatera-linked dinoflagellates and those of unknown identity to provide stock populations in positive identification using scanning electron microscopes.
Mr Bird qualified as a secondary teacher in 1988 after a difficult time studying as a single father of two in Australia. He met his wife Enid, who is administration manager at Heron Island Research Station, on his first posting the following year as a geology, geography and maths teacher at an English as a Second Language school in Nauru.
Ms Bird was secretary to the first two Nauruan presidents and acting administrator of the $100 million a year operation, Air Nauru. After developing an interest in marine biology, Mr Bird asked if she could relinquish her executive jobs and return to Australia with him.
'I told him everyone deserves a break sometime, and this is your time,' said Mrs Bird, who is supporting him during his studies.
Mr Bird completed his masters degree in 1996 at James Cook University of North Queensland and is in the second year of his PhD at the University of Queensland.
For further information, contact Mr Bird telephone 079 781 399, email: Paul.Bird@mailbox.uq.edu.au
