Toxic plankton (1990)
By Robert KertonJune 1st, 1990
Dr Gustaaf Hallegraeff from CSIRO’s Division of Fisheries sounds the alarm when a micro-alga, which is toxic to humans and threatens the shellfish industry, is introduced into Australia by container ships.
[Text appears: The Researchers – Toxic Plankton]
[Image changes to show the ocean]
[Image changes to show Doctor Gustaaf Hallegraeff throwing a collection net into the water]
Narrator: This is a scientific detective story in which a biologist discovers a disturbing new source of environmental danger.
[Image changes to show Doctor Gustaaf Hallegraeff]
Doctor Gustaaf Hallegraeff: The evidence of species that contaminate aquaculture products, that can kill humans, has been decisive evidence for the Quarantine and Inspection Service finally to get their act together.
[Music plays and text appears: The Researchers]
[Image changes to show Doctor Gustaaf Hallegraeff on a boat, collecting samples from the ocean]
Narrator: Doctor Gustaaf Hallegraeff is a Dutch born marine biologist working for CSIRO’s Division of Fisheries based in Hobart. Here he is taking samples of phytoplankton, the tiny microscopic plants which float in seawater.
[Image changes back to Doctor Gustaaf Hallegraeff]
Doctor Gustaaf Hallegraeff: These are among the first living organisms to evolve on our planet more than 400 million years ago.
[Image changes to show various images of phytoplankton]
These are the organisms that produce the oxygen in the atmosphere that we breathe today; these are the organisms that contributed significantly to the oil research that some of us use to drive our cars to work.
[Image changes to show Doctor Gustaaf Hallegraeff working in a laboratory]
They’re single celled organisms, and when you look at them under the electron microscope you’re overwhelmed by their beautiful patterns of geometry.
[Image changes to show images of phytoplankton]
[Image changes to show Doctor Gustaaf Hallegraeff taking a photo of the phytoplankton]
[Image changes to show various pictures of phytoplankton]
They have horns, wings, all the structures that humans thought they invented, like the wheel, the plankton already invented more than 400 million years ago.
[Image changes to show Doctor Gustaaf Hallegraeff looking through a microscope]
[Image changes to show Dinoflagellates]
Narrator: One group of phytoplankton, called Dinoflagellates, forms long chains. A few of these species are the villains of our story. They produce potent neurotoxins which can cause paralysis and death in human beings. It’s called PSP, or paralytic shellfish poisoning.
[Image changes to show shellfish farmers hauling in their catch onto a boat]
For shellfish farmers Gustaf’s research has very practical implications. Mussels, oysters and scallops eat the Dinoflagellates and concentrate the poison in their bodies. They are immune, but the toxin can kill birds, seals, whales and humans. Until recently these shellfish were free of the toxic plankton; it had never been found in Australian waters.
[Image changes to show a shellfish farmer opening a fresh mussel]
Here a fresh mussel has always been a safe mussel.
[Image changes to show Doctor Gustaaf Hallegraeff throwing a collection net into the water]
But in 1986 Doctor Hallegraeff dropped his net into the Derwent Estuary and changed the shellfish industry forever.
[Image changes back to Doctor Gustaaf Hallegraeff]
Doctor Gustaaf Hallegraeff: I just had been transferred from Sydney to Hobart, and my very first plankton sample that I collected outside these laboratories in the Derwent River contained a bloom of these toxic Dinoflagellates. I knew my literature, and I knew that this organism had killed children in Mexico.
[Image changes to show Doctor Gustaaf Hallegraeff making a telephone call]
Narrator: Doctor Hallegraeff immediately notified the Tasmanian Department of Sea Fisheries.
Doctor Gustaaf Hallegraeff: Just found first evidence for the presence of the toxic Dinoflagellates species in the Derwent River, and this organism has the potential to contaminate commercial shellfish farms in the D’Entrecasteaux Channel and the Huon River.
[Image changes to show a man collecting oyster samples]
Narrator: The Department set up a monitoring system to check the oysters for contamination. It turns out they were only just in time.
[Image changes to show various newspaper headlines]
That summer the first toxic concentrations appeared. A dozen oyster and mussel farms were closed for several months. By winter the toxins had disappeared and the bans were lifted. Since then contamination alerts have become an essential fact of life.
[Image changes to show an oyster sample being tested]
[Image changes to show oyster traps being raised out of the water onto a boat]
The monitoring program is economically very important. It guarantees purity for the lucrative international market.
[Image changes to show John Bailey – Shellfish farmer]
John Bailey: We really can get into almost any country in the world with our shellfish sanitation program, so that opens the world for us. We can sell our shellfish really almost anywhere.
[Image changes to show Doctor Gustaaf Hallegraeff on a boat, collecting samples from the ocean]
Narrator: Doctor Hallegraeff was left with a question – where did the Dinoflagellates come from? He sampled the sediment in the estuary and found no evidence of toxic phytoplankton in the past. He suspected they’d been brought in accidently by large ships, mostly Japanese woodchip vessels.
[Image changes to show a large ship moored in a harbour]
These ships come to Australia empty. For stability they are loaded with thousands of tonnes of ballast. They use seawater, which usually comes from heavily polluted coastal areas. Every year 60 million tonnes of imported water is dumped around Australia.
[Image changes to show the stored seawater in the large vessel]
[Image changes to show mud samples]
Mud samples taken from the bottom of the ballast tanks of visiting cargo vessels provided conclusive proof to Gustaaf and his colleagues.
[Image changes to show Dinoflagellates spores]
Nestled in the mud were thousands of Dinoflagellates spores, the tough resting state which is rather like a seed.
[Image changes back to Doctor Gustaaf Hallegraeff]
Doctor Gustaaf Hallegraeff: These spore stages are extremely resistant and they can be sleeping in these sediments for ten, 20 years, and when the conditions are suitable they germinate and produce new toxic Dinoflagellates blooms in the water column. And we’ve found these species now in the ports of Hobart, Adelaide and Melbourne.
[Image changes to show shellfish farmers tipping oysters onto the floor of a boat]
Narrator: The shellfish industry all around Australia is vulnerable to many other creatures hitchhiking in ballast tanks. Our marine agriculture is now protected by voluntary quarantine guidelines.
[Image changes back to Doctor Gustaaf Hallegraeff]
Doctor Gustaaf Hallegraeff: These guidelines include, for example, ships coming to Australian ports have been asked to exchange and clean out their ballast tanks in the open ocean, far away from Australian waters, and under no conditions should any discharge of ballast water be permitted in sensitive aquaculture areas.
[Image changes to show a CSIRO boat leaving a port]
Narrator: Doctor Hallegraeff has conclusively proved that ballast seawater is a dangerous carrier of marine pests.
[Image changes to show Doctor Gustaaf Hallegraeff on a boat, collecting samples from the ocean]
There are many more organisms which could travel the same international route. Now that the alert has been sounded the Australian system will probably be adopted by governments around the world.
[Image changes to show CSIRO logo and text appears: CSIRO Australia. Copyright © MCMXC]