Discovery News: Environmental

Antarctic Wildlife Feels the Heat

Today at Discovery News we reported on work by three researchers who study different aspects of the Antarctic ecosystem, and who decided to get together and tell the combined story of the changes they've seen over the last two or three decades as a result of climate change.

We thought we'd post it here so you could have your say. Do you care about what's happening in Antarctica? Are you ready to start marching for the penguins? What strikes you about the researchers' findings?

Also, stay tuned at the end of the post for some extra tidbits that didn't fit in the original story.

(Photo: Juvenile krill, Jim McClintock)

At Antarctic Peninsula, Fast Change
Jessica Marshall, Discovery News

 

July 10, 2008 -- From the tiny phytoplankton living under the ice to the penguins at the top of the food chain, the ecosystem of the Antarctic Peninsula is changing fast, driven by warming waters and a loss of sea ice.

Three researchers who have spent decades studying Antarctica's denizens paint a picture of interconnected changes at the bottom of the Earth that are changing the ecology over just decades after some 30 million years of relative isolation.

"The changes are profound," said Hugh Ducklow of the Marine Biological Research Laboratory in Woods Hole, Mass.

He and colleagues James McClintock of the University of Alabama at Birmingham and William Fraser of Polar Oceans Research Group in Sheridan, Mont. compiled their findings from studying different aspects of the Antarctic ecosystem in an article in the current issue of American Scientist.

Nowhere on Earth is climate change happening faster than on the neck of land stretching north from the Antarctic continent more than 900 miles toward South America. The average midwinter temperature on the Antarctic peninsula has increased more than 10 degrees Fahrenheit since 1950, five times the global average.

The changes the researchers see begin at the base of the food web, with phytoplankton -- tiny photosynthetic organisms that, in Antarctica, are evolved to live in the sea ice. As the extent of sea ice has decreased, so has the amount of phytoplankton.

"Sea ice is not just ice," Ducklow said. "It's a habitat for organisms."

Indeed, juvenile krill, tiny shrimplike organisms that serve as the main food source for Adélie penguins and baleen whales, graze on the phytoplankton under the sea ice.

"Juvenile forms of krill are not as strong swimmers as adults," Ducknow said "By congregating on the underside of the ice, they get a shelter from predators, and it's where the food is."

Krill have been declining for decades, the authors note, although sea ice decline may not be the only reason.

With less krill to feed on, organisms at the top of the food chain like Adélie penguins suffer. Their populations have been decreasing in the central and northern Antarctic peninsula.

The Adelie penguins also rely on the sea ice directly. In winter, they use the sea ice to get out to hotspots of food. As this shrinks, their food will be too far away to swim to.

In contrast, two related species, the gentoo and chinstrap penguins, do not rely on sea ice for winter feeding. Their populations are rising on the Peninsula.

Meanwhile, another Antarctic community is poised to change because of rising sea temperatures.

Since the Antarctic Peninsula separated from South America 25 to 35 million years ago, Antarctica has been encircled by the Antarctic Circumpolar Current, a clockwise roundabout current that holds cold water near the continent and isolates it from the rest of the ocean.

Crabs and other predators that get prey by cracking shells with strong forces were excluded from the region once the current was established, because they cannot survive at such cold temperatures.

Without such predators to guard against, animals like snails and clams in Antarctica evolved delicate, thin shells. But as the ocean warms, crab predators may move in and have defenseless prey to capitalize on. A colony of king crabs was recently found in deeper waters off the peninsula.

"It's only a matter of time before they can move up into even shallower water," said lead author McClintock, who studies Antarctica's invertebrates. "When crabs get into those communities of clams and snails and brachiopods, they are going to be history."

McClintock notes that the reproductive cycle of invertebrates is also closely tied to temperature, and warming may lead to larvae hatching out of sync with the availability of their plankton food supply.

But, he adds, kelp-like macroalgae are likely to thrive with the greater availability of sunlight thanks to reduced sea ice. And jellyfish will probably also increase in number.

What is clear is that these populations are shifting fast in relation to one another, and the ecosystem that emerges will be different from the one that has existed in isolation for millions of years.

"People say, why Antarctica? Who cares about that?" Ducklow said. "It's a canary in the coal mine. We're seeing things happen rapidly there. It's a good wakeup call for us that there is climate change, and ecosystems really are responding to it."

******************************************

Now, here's the extra bit that I'll call

Amazing Antarctic Facts

• The reason that crabs have heretofore been unable to survive in Antarctic waters is that they cannot expel magnesium from their bloodstream. Magnesium acts as a narcotic whose effect is enhanced at low temperatures. So, until now, any crabs that decided to go strolling in too-chilly waters became immobilized and died.
• Another species that is threatened by changing sea ice is the Waddell seal. Female adult seals get a private, predator-protected birthing room by using their ice-chipping teeth to scratch open a hole in the sea ice from underneath. They pop through the hole onto the surface when they're ready to pop out their young. According to McClintock, "The price they pay for these teeth is that over the years they wear down the teeth and they starve." They live about half as long as other seals, he said, but more of their young survive.
• About 70 percent of Antarctic species are found nowhere else.
• The sea ice in midwinter is about as big as the lower 48 U.S. states, but with a lot fewer Starbucks.
• Antarctic ice holds almost 2/3 of Earth's freshwater.
• Climate change has brought more snowstorms to the Peninsula. These have also harmed Adélie penguins. When it snows in spring, the nests can flood, killing eggs and hatchlings.
• If warming trends continue, the average midwinter temperature will be above freezing (for seawater) by mid-century. Sea ice will no longer form.

Volcanic Death Plume

I hope you checked out the amazing videos of undersea volcanic explosions in the Pacific posted today at Discovery News.

In addition to offering glowing lava, exploding rock, and billowing, sulfurous clouds, this environment supports some interesting biology.

The main macrofauna consists of a pair of shrimp species living within a few hundred feet of the vent. One type of shrimp grazes on bacterial mats growing on chemicals spat out by the volcano. The other type feeds on the smaller shrimp.

While the volcano supports life below, it kills life above. The team found that if fish or other marine life in the upper ocean swim into the plume of water rising from the volcano, the unusual chemical composition of the water stuns or kills them. They drop to the sea floor, and the shrimp get some tasty snacks. Who says there’s no such thing as free lunch?

Check out some pictures of plume-kill and videos of the shrimp here.

For more information and videos from the expedition, charismatically called the "Submarine Ring of Fire 2006 Exploration", check here.

(Image: Image Submarine Ring of Fire 2006 Exploration, NOAA Vents Program)

Chuck E Cheese Playground? No, It's a Reservoir

The LA Times reported yesterday that the city’s Department of Water and Power dumped 400,000 black plastic balls on a drinking water reservoir.

Why? To prevent the formation of bromate, a carcinogen that forms when bromine, found naturally in groundwater, reacts with chlorine in the presence of sunlight. The balls, which are commonly used to blanket wastewater ponds or water accumulation sites near airport runways to prevent birds from landing on them, are intended to shade the water and prevent the reaction from occurring. It will take about 3 million balls to fully cover the reservoir.

Bromate levels got high enough in a neighboring reservoir that they had to drain it earlier this year.

The balls are made of UV-resistant high density polyethylene, which is listed as a non-leaching type of plastic, but it still strikes me as disconcerting to float so many pieces of plastic in the drinking water in the presence of chlorine and sunlight, which may promote breakdown reactions.

The ball shading technique is a temporary measure. Newer water regulations say that potable water should not be stored in the open air, so the balls are there until the new storage tanks are finished in a few years.

Check out some great pictures of the ball release here and a video here.

(Image: Actually, a McDonald's playground, Julie70)

Mussel Bound

Jennifer Viegas wrote a great story about the decline of a critical Great Lakes crustacean, probably because of invasions of zebra and quagga mussels in the Great Lakes.

These troublesome mussels are no longer limited to the Great Lakes region. In January 2007 quagga mussels were first found west of the Continental Divide in Lake Mead, Nev. They have since moved downstream in the Colorado River and into California, where they threaten to clog the waterworks that supply drinking water to millions.

The zebra mussel turned up in California in 2008.

The U.S. Geological Survey now tracks these invaders in an interactive Google Map updated daily (zebra mussels here and quagga mussels here). See where they’ve spread.

"We really want people not to spread these around," said Amy Benson of the USGS in Gainesville, Fla. "If you can look at our map and see that they’re in this lake, then you might not go fishing there."

"The public is so important in this," she added.

(Images: Instrument encrusted with zebra mussels, Lake Michigan, NOAA. Benson, A. J. 2008. Zebra mussel sightings distribution. Retrieved 31 May 2008 from here.)

 

Meat, Meat, Meat

The take home message from everyone I’ve been speaking with recently is that meat--especially beef--is just no good for the environment.

First, Christopher Weber at Carnegie Mellon University published findings showing that shifting a quarter of the average American’s red meat consumption to other foods saved as much greenhouse gas emissions as going entirely local, i.e. red meat has a really big carbon footprint.

Then, I spoke with researchers highlighting the importance of considering our “nitrogen footprint”, too. “Meat is one of the main drivers of acceleration of the cycle,” said Alan Townsend of the University of Colorado at Boulder. “To have meat diets under modern agriculture takes a lot of nitrogen. You end up having to have a lot of fertilizer and a big chunk of field to grow a few cows or pigs.”

Finally, the Stockholm International Water Institute issued a report about water… You guessed it: meat production takes lot of water. Their report estimates that about 50 percent of calories grown in fields never make it to the table, and about half of that loss is animal feed that doesn’t end up as a calorie on a cow, pig, chicken, or other edible critter. Growing those lost calories takes a lot of water.

For the most part, each of these impacts comes from the same cause: growing a pound of meat requires (much) more than a pound of grain. A pound of beef, for instance, requires eight. (The conversions are better for other types of meat, but never 1:1).

This inefficiency amplifies the demand for nitrogen fertilizer and irrigation, and leads to more of the greenhouse gas emissions associated with growing crops. These emissions come from energy for making fertilizer and release of nitrous oxide (N2O)—a super greenhouse gas almost 300 times more potent than CO2—by bacteria acting on fertilizer in the soil.

With cattle, greenhouse gas emissions also result from methane (23 times more potent than CO2) released by digestion, and nitrous oxide production from manure. 

The SIWI report points out that demand for meat is rising fast. Here are some meat consumption numbers for different parts of the world:

--Southeast Asia: ~88 lbs/person/year in 2002, a sevenfold increase from 1961, when it was 13 lbs.
--India: Projected at 22 lbs/person/year in 2050 (Thanks to a largely vegetarian population.)
--China: Projected at 183 lbs/person/year in 2050
--US: 200 lbs/person/year in 2005, up 22 lbs from 1970

It’s also worth pointing out that dairy creates these impacts, too, though not to the same extent as meat.

Is Grass-Fed Beef Better?
So grain-fed beef is no good… but what about grass-fed? If you read Michael Pollan’s book, The Omnivore’s Dilemma, you might have been convinced, like me, that eating a bit of grass-fed beef was fine--even good. When cows eat grass, they’re converting plant calories that we can’t eat (i.e. grass) into calories that we can. This is an efficient way to harness the energy from the sun in food form in places that aren’t suitable to grow crops.

But, how much does the greenhouse gas footprint change when you switch to grass-fed beef? Then you don’t need those eight pounds of grain. Christopher Weber kindly did some math to help answer this question (Thanks, Christopher!). He cautions that these numbers are approximate and un-reviewed, but here they are:

“By switching to grass fed, you remove around 20% of the CO2 and 60% of the N2O in the supply chain of making and delivering grain to the farms.
So, if there is no increase in methane and manure emissions (of CH4 and N2O) are not being captured at the feedlot, there's approximately a 25% reduction in life cycle greenhouse gas emissions in grass fed vs. grain fed.”

But don’t stop reading. Studies have shown that grass-fed beef produces more methane than grain-fed beef. (Though at least one study has reported the opposite, Weber said.) This offsets some of the gains:

“If the grass-fed has 15% more methane, which is around the number I've seen cited, then grass fed is only 20% better.”

So, while there may be other advantages to eating grass-fed beef over grain-fed, it’s still not a climate-neutral choice. And, as Marshall Burke of Stanford University pointed out, if everyone switched to grass-fed beef, there wouldn’t be enough pastureland to go around.

To the climate conscious: learn to love lentils.

(Photo: Grant Hutchinson)

Water, Water

Today I wrote about a new report that highlights the importance of conserving water globally as demand grows and climate change threatens to disrupt supply.

Folks in my former hometown of Berkeley, Calif., are getting a crash course in water conservation. Last week the East Bay Municipal Utility District rolled out water rationing for the 1.3 million people in their service area, which includes Oakland and Berkeley, in response to two dry years in a row and a snowpack in the Sierra Nevada mountains—a major source of water to the region--at 67 percent of normal.

Following the initial call for residential consumers to reduce water use by 19 percent, plenty of community members complained, saying they already conserve and would have difficulty cutting back further.

They had a point. The top 1 percent of residential users in the area each consume over 1000 gallons a day, about 5 percent of total use, according to EBMUD, while the lowest-consuming 18 percent of users each draw less than 75 gallons a day, about 2-3 percent of the total. The average household in the EBMUD service area uses about 200 gallons of water a day.

In response to complaints, the agency will not require households using less than 100 gallons a day to conserve further. For others, rates will go up 10 percent, and if consumers fail to cut back by at least 10 percent relative to their average usage, they’ll be charged $2 for every 100 cubic feet (748 gallons) they use beyond their allotment.

(I might add that $2 extra for a four-day supply of water really doesn’t seem like a lot. Marshall Burke, of Stanford University, whom I spoke with for the article I wrote today, highlighted this point: “Water is incredibly subsidized. Why should we be growing alfalfa--one of the most water-intensive crops--in the Imperial Valley? It’s because water is so cheap.”)

An article in the San Francisco Chronicle highlights some strikingly different responses to the plan. Here are a couple of excerpted quotes:

"I've got half an acre of lawn, a swimming pool and three teenagers," said Alex Theriault, a contractor from Danville whose bi-monthly water bills top $1,400. "I can't afford not to cut back. But I'm not losing the lawn. My kids like it too much. And I'm not losing the pool. I like the pool."

and

"We've been really lax about water here, compared to other countries," said Debbie Wilson, a mom from Pleasant Hill who brought her children to play in the recycled-water fountain in downtown Pleasant Hill.

"Right now, our automatic sprinklers come on every day," she said. "We'll change that. We need to have water for more important things."

This all gets at the fact that what people consider reasonable conservation varies. A lot. Some people are OK with the “if it’s yellow let it mellow” approach to toilet flushing, while others aren’t willing to lose the lawn, let alone leave pee in the toilet. Much of this is cultural. Depending on who your friends are, peer pressure can push toward greening your lawn, or your lifestyle.

Things like rationing help drive cultural shifts, bringing “fringe” conservation behavior into the mainstream. EBMUD spokesman Charles Hardy told the Chronicle:

"You'd be surprised how many neighbors call in when they've been trying hard to conserve water and they see someone out there washing their car without a shut-off nozzle."

What we need to do is to drive cultural shifts elsewhere—for water, fuel and energy conservation--before rationing is necessary.

(Photos: Milica Tepavac , Ruy Lestrade)