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Oceans 40% Fouled By Pollution, Fishing, Warming, Study Says
By Alex Morales
Feb. 14 (Bloomberg) -- Fishing, pollution and climate change damaged more than two-fifths of the world's oceans,

said scientists who produced a map of the human toll on marine life.
Every single square kilometer of the oceans is affected by something man-made, and 41 percent has a ``medium high''

or ``high'' impact, the scientists, led by Ben Halpern at the University of California, Santa Barbara, said in an article to

be published in the journal Science Feb. 15.
The researchers examined 17 ways that humans affect oceans, including shipping lanes, oil and gas exploration, and

invasive species, and mapped the effects across coral reefs, mangroves and continental shelves. The map will help world

policymakers protect the oceans, Halpern said in a telephone interview.
``A lot of the past studies have looked at just a single activity -- fishing or climate change or land-based runoff pollution,

and they looked at the impact of just one of those,'' Halpern said yesterday. ``We've looked at the overlaying cumulative

sum of all of these activities at once, so you can really get a big picture of how humans are affecting the oceans.''
Oceans near the poles were unaffected by humans. The North Sea and the South and East China Seas were heavily

impacted, said Halpern. The Mediterranean, east Caribbean, Persian Gulf, Norwegian Sea, Bering Sea, the east coast

of North America and the waters around Sri Lanka were also among the worst, the article said.
`Degraded State'
``Those areas are definitely in a degraded state, and a state that if people went diving in, probably would not be too

happy to be in,'' Halpern said.
Reefs and mangroves, coastal habitats that receive a lot of attention from conservationists, were heavily damaged by

human activities, the study said. Worst were rocky reefs and continental shelves, where commercial fishing concentrates,

Halpern said.
``Where you're in a very high impact situation, it's fairly heavily degraded, and the ecosystem is probably not something

people would even recognize as a normal healthy ecosystem,'' Halpern said. ``It probably means that most of the big

fish and invertebrates are gone and that the plants and animals that live on the bottom are much less abundant than

they used to be.''
Climate change had the biggest impact on oceans, raising temperature, acid levels and ultraviolet radiation, Halpern said.
Worse Picture
``In coastal areas, you get everything from land-based pollution, and oil and gas development, invasive species as well

as climate change and fishing causing problems,'' he said.
The map created by the scientists doesn't include fish farming or sediment runoff from dammed rivers, said Halpern,

who said the group's estimates were conservative.
``There are going to be interactions among these different activities that makes the whole much greater than the parts,''

Halpern said. ``The picture would probably look worse if you accounted for these interactions.''
Effective ocean-management can stop the degradation, the study said. Climate change likely will intensify the damage,

 according to the scientists.
Policy makers should use the scientists' map to separate harmful ocean activities, so negative effects aren't magnified,

Halpern said.
``We have business districts and residential districts, schools and churches. All these things are zoned into different

places to create some cohesion to our communities that make sense. You don't have a strip club next to a school,'' the

researcher said. ``We can allow all these activities to go on, but just not in the same place.''
To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net .

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 Probing Question: What is a red tide?

Although its name sounds like a low-budget horror movie, you won't find "Red Tide" at a theater near you. To take in

this natural phenomenon, you'll have to venture to the ocean, because red tide — or more scientifically, HAB or harmful

algae bloom — occurs when a harmful variety of algae reproduces so densely that the water appears red, yellowish-brown

or green from the high concentrations of photosynthetic pigments.

Explained Michael Arthur, a Penn State geosciences professor with research expertise in marine ecosystems, most varieties

 of algae are harmless and occupy an essential tier of the food chain.

The algae responsible for red tide, however, is one of a few dozen species of phytoplankton called dinoflagellates that,

under the right conditions, produce toxins. The level of toxicity depends on the specific algal variety involved, with the

most dangerous species emitting potent neurotoxin that can kill marine and coastal wildlife, and can even cause illness

or death in humans.

But why do these blooms occur?

According to Arthur, "Blooms can't occur unless the algae is already present in the water, and the right nutrients are

present — particularly nitrogen and phosphorus — to supply the raw materials that stimulate rapid growth of the algae

population."

Aided by warm water and stagnant surface conditions, nutrients play a large part in allowing the algae to reproduce so

quickly. Arthur said one source of these nutrients comes from upwelling, a process where colder, deeper ocean water is

brought up to shallower water, bringing nutrients with it. Upwelling along the U.S. West Coast may have a lot to do with

the high incidence of blooms in that region. The bluish-green glow, or bioluminescence, of the relatively harmless

dinoflagellate species Noctiluca scintillans, is a common sight in California's waters.

However, Karenia brevis — the microorganism responsible for most red tides in Florida's Gulf of Mexico — is a much

redder and more dangerous strain. A 2005 outbreak along Florida's southwest coast was described in The New York

Times as one of the state's "worst red tides in decades." At its peak, it caused a 2,000 mile-wide "dead zone" off the city

of St. Petersburg that was responsible for "more than 950 tons of dead creatures" that washed up on area beaches.

Ironically, hurricanes typically bring relief by diluting the concentration of algae, but even Hurricane Katrina didn't end

Florida's 2005 ferocious outbreak.

Areas where pollution drains into the ocean often experience algae blooms, Arthur noted. He suspects excess nutrification

 is the cause. "Blooms have been observed around aquaculture sites and fish farms where nutrients are being shed into

the surrounding water," he said. "Fertilizer run-off from farmland and sewage waste also add to the nutrient content,

supplying the algae with a more abundant food source."

According to the National Oceanic and Atmospheric Association (NOAA), over 50 percent of unusual marine mammal

mortality events are due to harmful algae blooms. While shellfish such as clams, mussels and oysters are not directly

harmed by red tide, their filter-feeding systems store the algae's toxins in their tissue. If tainted shellfish is ingested, they

can have a deadly affect.

As Arthur explained, "Paralytic Shellfish Poisoning (PSP) and other syndromes caused when people eat tainted shellfish

can cause catastrophic damage to victims' cardiovascular, digestive and/or neurological systems. Some, including PSP, are

potentially fatal. If you contract this condition," he continued, "the first symptom you'll likely notice is a numbness on

your tongue. If this occurs, you should get medical help immediately. Breathing machines have saved lives in this situation.

Otherwise, the heart keeps beating but the paralyzed lungs fail, leading to death."

Reported occurrences of PSP in coastal areas have increased in the last 30 to 40 years. Arthur said it's possible that the

condition is simply more widely recognized today and therefore more accurately reported. There also are more people

living in coastal areas, as well as better monitoring systems to locate PSP-carrying algae. However, he suggested that the

increase is likely due at least in part to an actual increase in HAB. Warmer water temperatures resulting from climate change have

tentatively been associated with algae blooms, though research is continuing on the subject.

To those who consume seafood, Arthur suggested, "You have to be careful and know where things come from. Don't

just walk along the beach, pick up an oyster or mussel, and pop it into your mouth." Watch the news for "red tide alerts"

 and, when dining at a seafood restaurant, "use the buddy system," he advised, "so that you can notice physical or

 behavioral changes in each other that might signal shellfish poisoning."

Caution is the watchword, because although "Red Tide" may not be a horror movie, its impact can be pretty horrific.

Source: By Marissa McCauley, Research/Penn State 


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