Noxious weed signals an ocean out of balance
Los Angeles Times
First of three parts
MORETON BAY, Australia —
The fireweed began each spring as tufts of hairy growth and spread across the seafloor fast enough to cover a football field in an hour.
When fishermen touched it, their skin broke out in searing welts. Their lips blistered and peeled. Their eyes burned and swelled shut. Water that splashed from their nets spread the inflammation to their legs and torsos.
As the weed blanketed the bay over the past decade, it stained fishing nets a dark purple and left them coated with a powdery residue. When fishermen tried to shake it off the webbing, their throats constricted, leaving them gasping for air.
After one man bit a fishing line in two, his mouth and tongue swelled so badly that he couldn't eat solid food for a week. Others made an even more painful mistake, neglecting to wash the residue from their hands before relieving themselves over the side of their boats.
For a time, embarrassment kept them from talking publicly about their condition. When they finally did speak up, authorities dismissed their complaints — until a bucket of the hairy weed made it to the University of Queensland's marine botany lab.
Samples placed in a drying oven gave off fumes so strong that professors and students ran out of the building and into the street, choking and coughing.
Scientist Judith O'Neil put a tiny sample under a microscope and peered at the long black filaments. Consulting a botanical reference, she identified the weed as a strain of cyanobacteria, an ancestor of modern-day bacteria and algae that flourished 2.7 billion years ago.
O'Neil, a biological oceanographer, was familiar with these ancient life forms, but had never seen this particular kind before. What was it doing in Moreton Bay? Why was it so toxic? Why was it growing so fast?
The venomous weed, known to scientists as "Lyngbya majuscula," has appeared in at least a dozen other places around the globe. It is one of many symptoms of a virulent pox on the world's oceans.
In many places — the atolls of the Pacific, the shrimp beds of the Eastern Seaboard, the fjords of Norway — some of the most advanced forms of ocean life are struggling to survive while the most primitive are thriving and spreading. Fish, corals and marine mammals are dying while algae, bacteria and jellyfish are growing unchecked.
Where this pattern is most pronounced, scientists evoke a scenario of evolution running in reverse, returning to the primeval seas of hundreds of millions of years ago.
Jeremy B.C. Jackson, a marine ecologist and paleontologist at the Scripps Institution of Oceanography in San Diego, says we are witnessing "the rise of slime."
For many years, it was assumed that the oceans were too vast for humanity to damage in any lasting way. Even in modern times, when oil spills, chemical discharges and other industrial accidents heightened awareness of man's capacity to injure sea life, the damage was often regarded as temporary.
But over time, the accumulation of environmental pressures has altered the basic chemistry of the seas.
Industrial society is overdosing the oceans with basic nutrients — the nitrogen, carbon, iron and phosphorous compounds that curl out of smokestacks and tailpipes, wash into the sea from fertilized lawns and cropland, seep out of septic tanks and gush from sewer pipes. These pollutants feed excessive growth of harmful algae and bacteria.
At the same time, overfishing and destruction of wetlands have diminished the competing sea life and natural buffers that once held the microbes and weeds in check.
Evidence is surfacing around the globe.
Off the coast of Sweden each summer, blooms of cyanobacteria turn the Baltic Sea into a stinking, yellow-brown slush that locals call "rhubarb soup." Dead fish bob in the surf.
On the southern coast of the Hawaiian island of Maui, high tide leaves piles of green-brown algae that smell so foul condominium owners have hired a tractor driver to scrape them off the beach every morning.
On Florida's Gulf Coast, residents complain that harmful algae blooms have become bigger, more frequent and longer-lasting. Toxins from these red tides have killed hundreds of sea mammals and caused emergency rooms to fill up with coastal residents suffering respiratory distress.
North of Venice, Italy, a sticky mixture of algae and bacteria collects on the Adriatic Sea in spring and summer. This white mucus washes ashore, fouling beaches, or congeals into submerged blobs, some bigger than a person.
Organisms such as the fireweed that torments the fishermen of Moreton Bay have been around for eons. They emerged from the primordial ooze and came to dominate ancient oceans that were mostly lifeless. Over time, higher forms of life gained supremacy.
"We're pushing the oceans back to the dawn of evolution," Jackson said, "a half-billion years ago when the oceans were ruled by jellyfish and bacteria."
In Australia, fishermen began noticing the fireweed around the time much of Moreton Bay started turning a dirty, tea-water brown after every rain. The wild growth smothered the bay's northern sea-grass beds, once abounding in fish and shellfish, under a blanket a yard thick.
After suffering painful skin lesions, fisherman Greg Savige took a sealed bag of the weed in 2000 to Barry Carbon, then director-general of the Queensland Environmental Protection Agency. He warned Carbon to be careful with it. Carbon replied that he knew all about cyanobacteria from western Australian waters and that there was nothing to worry about.
Then he opened the bag and held it to his nose.
"It was like smearing hot mustard on the lips," the chastened official recalled.
Each spring, Lyngbya bursts forth from spores on the seafloor and spreads in dark green-and-black dreadlocks. It flourishes for months before retreating into the muck. Scientists say it produces more than 100 toxins, probably as a defense mechanism.
At its peak in summer, the weed now covers as much as 30 square miles of Moreton Bay, an estuary roughly the size of San Francisco Bay.
Suspecting that nutrients from partially treated sewage might be the culprit, Queensland University scientist Peter Bell collected some wastewater and put it in a beaker with a pinch of Lyngbya. The weed bloomed happily.
As Brisbane and the surrounding area became the fastest growing region in Australia, millions of gallons of partially treated sewage gushed from 30 wastewater treatment plants into the bay and its tributary rivers. Officials upgraded the sewage plants to enable them to remove nitrogen from the wastewater, but it did not stop the growth of the infernal weed.
Researchers began looking for other sources of Lyngbya's nutrients, and are now investigating whether iron and possibly phosphorous are being freed from soil as forests of eucalyptus and other native trees are cleared for development.
"We know the human factor is responsible. We just have to figure out what it is," said William Dennison, then director of the University of Queensland botany lab.
Lyngbya can pull nitrogen out of the air and make its own fertilizer. It uses a different spectrum of sunlight from algae's, so it can thrive even in murky waters. Perhaps its most diabolical trick is its ability to feed on itself. When it dies and decays, it releases its own nitrogen and phosphorous into the water, spurring another generation of growth.
"Lyngbya has lots of tricks," said scientist Judith O'Neil. "That's why it's been around for 3 billion years."
For some Moreton fisherman, the only solution is to turn away from the sea.
Lifelong fisherman Mike Tanner, 50, stays off the water at least four months each year to avoid contact with the weed. Before the Lyngbya outbreak, 40 commercial shrimp trawlers and crab boats worked these waters. Now there are six, and several of them sit idle during fireweed blooms.
"It's the only thing that can beat us," Greg Savige said. "Wind is nothing. Waves, nothing. It's the only thing that can make us stop work. When you've got sores and the skin peels away, what are you going to do?"
Copyright © 2006 The Seattle Times Company