What’s going on with the oceans and what can we do?

As carbon dioxide (CO₂) rises in our atmosphere, the oceans absorb roughly a quarter of the amount. This lowers the pH level in the seawater, making the oceans more acidic. How this affects life in and out of the sea is continually studied.

This week, ocean acidification is the topic of several scientific papers. We thought we’d highlight a few of them here.

Nature Climate Change has two papers—one about the affect of acidification on several different species, and the other on how ocean acidification causes even more global warming.

For the first paper, German researchers surveyed previous studies that dealt with the consequences of ocean acidification for marine species from five animal taxa: corals, crustaceans, mollusks, fish, and echinoderms. By the end, they had compiled a total of 167 studies with the data from more than 150 different species.

Their findings? Different species are affected in different ways and to different extents, but all species are negatively affected by ocean acidification. “Our study showed that all animal groups we considered are affected negatively by higher carbon dioxide concentrations. Corals, echinoderms, and mollusks above all react very sensitively to a decline in the pH value,” says lead author Astrid Wittmann, of the Alfred Wegener Institute.

The second study demonstrates that the negative effects of ocean acidification aren’t just limited to marine life. The authors discovered that rising ocean acidity has the potential to amplify climate warming in general, through the decreased production of a biogenic sulfur compound.

Phytoplankton in the ocean produce dimethyl sulfid (DMS). As DMS is released into the air, it creates atmospheric sulfur—which increases the reflectivity of the atmosphere to incoming radiation, reducing surface temperatures. Warming acidic oceans means the phytoplankton produce less DMS, causing an even warmer planet.

In addition to the Nature papers, Philosophical Transactions of the Royal Society B has an ocean acidification-themed issue this week, with nine papers studying its effects. The papers describe three distinct effects on marine life due to ocean acidification: species interactions, decreased ecosystem functions, and adaptations. Andrew Revkin has a great summary of them on his Dot Earth blog in the New York Times.

“It’s great that some of these papers are looking at entire ecosystems,” says Aaron Pope, the Academy’s sustainability manager who works tirelessly to communicate ocean acidification issues. “There’s been lots of research in the past on individual species impacts, but data on entire natural systems was missing. Now we can start to talk about what will really happen in marine ecosystems as ocean acidification gets worse.”

One paper of the group (from local researchers at San Francisco State University) looks at tiny coccolithophores. These single-celled algae are able to sequester oceanic carbon by incorporating it into their shells, providing ballast to speed the sinking of carbon to the deep sea. The little organisms are central to the global carbon cycle, a role that could be disrupted if rising levels of atmospheric carbon dioxide and warming temperatures interfere with their ability to grow their calcified shells.

This paper might provide a bit of hope among the rest: “At least in this experiment with one coccolithophore strain, when we combined higher levels of CO₂ with higher temperatures, they actually did better in terms of calcification,” says co-author Jonathon Stillman, of SF State.

Here’s to hoping that all of these papers findings will create more awareness of ocean acidification that will lead to more solutions.

Coccolithophore image: Alison R. Taylor/PLoS Biology

A team of scientists, led by Stanford’s Kevin Arrigo, broke through some of the Arctic ice last July as part of the NASA ICESCAPE mission and found the complete opposite—abundant life!

“If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible,” says Arrigo. “This discovery was a complete surprise.”

The researchers discovered an abundance of phytoplankton—microscopic life that forms the base of the marine food chain. Phytoplankton require sunlight for photosynthesis, just like plants. And sunlight has a tough time penetrating thick sea ice.

But that thick sea ice is changing. Not only are warmer temperatures thinning the ice, but as the ice melts in summer, it forms pools of water that act like transient skylights and magnifying lenses. These pools focus sunlight through the ice and into the ocean, where currents steer nutrient-rich deep waters up toward the surface. Phytoplankton under the ice evolved to take advantage of this narrow window of light and nutrients.

The phytoplankton displayed extreme activity, doubling in number more than once a day. Blooms in open waters grow at a much slower rate, doubling in two to three days. These growth rates are among the highest ever measured for polar waters. Researchers estimate that phytoplankton production under the ice in parts of the Arctic could be up to 10 times higher than in the nearby open ocean.

The phytoplankton bloom discovered by Arrigo and his colleagues in the Chukchi Sea (just north of Alaska) extends tens of meters deep in spots and about 100 kilometers (62 miles) across.

“At this point we don’t know whether these rich phytoplankton blooms have been happening in the Arctic for a long time and we just haven’t observed them before,” Arrigo says. “These blooms could become more widespread in the future, however, if the Arctic sea ice cover continues to thin.”

The discovery of these previously unknown under-ice blooms could have serious implications for the broader Arctic ecosystem, including migratory species such as whales and birds. Phytoplankton are eaten by small ocean animals, which are eaten by larger fish and ocean animals.

“It could make it harder and harder for migratory species to time their life cycles to be in the Arctic when the bloom is at its peak,” Arrigo says. “If their food supply is coming earlier, they might be missing the boat.”

The research is published this week in Science.

Image: NASA

We’ll give you the same update here each month, in the same order Ryan does, starting and ending closest to our home city, San Francisco.

Where’s the Snow?
Some of us were looking forward to sledding down our great neighborhood hills… On February 23rd, the San Francisco Chronicle reported “there is a good chance for snow at sea level in San Francisco for the first time since February 1976, the National Weather Service opines.” But on February 25th, it declared a “love-hate relationship with weather predictions.”

But everyone else got snow, according to NASA’s Earth Observatory:

January 2011 was marked by a series of crippling snow storms across the United States. By January 12, about 71 percent of the country had snow on the ground, the fifth-largest snow cover extent in the last 45 years.

While the snow-pack in the Sierras has been good for California, other states are not so lucky:

With all the snow, it would be easy to think that the United States received plenty of winter moisture, but snow is deceptive… January 2011 was the ninth-driest January in the United States in 117 years. The southern half of the country was particularly hard hit. New Mexico experienced its driest January on record.

Expedition to the Philippines
We mentioned this in Earth Update last month, but head Academy researcher Terry Gosliner outlined his plans, hopes and dreams for the upcoming Hearst Expedition to the Philippines at Nightlife last night. Academy scientists, working with Filipino researchers, will explore three research arenas in the country: shallow-water reefs, deep-sea,  and terrestrial and freshwater. The expedition will take place from April 25th through June 10th– look for updates here.

Australia and New Zealand Updates
Australia, land of floods, droughts and cyclones. Tropical Cyclones Diane and Carlos both hovered off the coast of Western Australia last month and Atu approached the north island of New Zealand. (Click on the links for more stunning images from the Earth Observatory.)

The 6.3-magnitude earthquake that struck Christchurch last month was surprising in the amount of damage it amassed. From Earth Observatory:

Besides striking closer to a major population center, the 6.3-magnitude Christchurch earthquake had a depth of just 5 kilometers (3 miles). The New Zealand Herald reported that, whereas the Darfield quake [September 2010] happened in the early morning hours, the February 22 quake struck at the “worst possible time” of day—at the lunch hour when city streets were crowded with shoppers, diners, office workers, and school children. Moreover, some of the buildings that collapsed may have been weakened by the September 2010 quake.

It’s also possible that the quake could have been magnified by volcanic rock.

Let’s look to some beauty of the area. The image above is not a painting; it shows the annual summer phytoplankton bloom, taken February 10th.

Goodbye Glory
Ryan reported on the Glory satellite launch to his NightLife crowd last night. Sadly, only a few hours later, early this morning, the climate-data gathering spacecraft failed to separate from the Taurus XL rocket and plunged somewhere into the South Pacific. We saw this same thing only two years ago with the Orbiting Carbon Observatory satellite. You can read more here.

If you’re in the area, come visit the Academy for NightLife on April 7th for the next “Earth Update,” when Ryan and Tim will give you more of the latest news on Academy research and our home planet.

NASA image by Norman Kuring

These microscopic marine algae form the basis of the marine food chain and sustain a number of diverse species ranging from tiny zooplankton to large marine mammals, seabirds, and fish.

“Phytoplankton is the fuel on which marine ecosystems run. A decline of phytoplankton affects everything up the food chain, including humans,” according to Daniel Boyce the lead author of a new study published in the July 29th edition of Nature.

The cause of the phytoplankton decline? Rising ocean temperatures.

Ed Yong in Discover writes that:

Phytoplankton need sunlight to grow, so they’re constrained to the upper layers of the ocean and depend on nutrients welling up from below. But warmer waters are less likely to mix in this way, which starves the phytoplankton and limits their growth.

Using an unprecedented collection of historical and recent oceanographic data, Boyce and his team documented phytoplankton declines of about 1% of the global average per year. Again, from Discover:

Boyce’s study… really began in 1865, when an Italian priest and astronomer called Father Pietro Angelo Secchi invented a device for measuring water clarity. His “Secchi disk” is fantastically simple—it’s a black-and-white circle that is lowered until the observer can’t see it any more. This depth reveals how transparent the water is, which is directly related to how much phytoplankton it contains. This simple method has been used since 1899. Boyce combined it with measurements of the pigment chlorophyll taken from research vessels, and satellite data from the last decade.

The scientists found that long-term phytoplankton declines correlated directly with rising sea surface temperatures and changing oceanographic conditions. Their data also matched fluctuating weather patterns such as El Niño.

While rising ocean temperatures may contribute only partly to the phytoplankton decline (articles in Nature and the BBC also mention ocean circulation, wind and over-fishing), we should pay attention. For phytoplankton not only feeds the seas, it also, according to the BBC, sustains all life. “Photosynthesis by phytoplankton removes carbon dioxide from the air and produces oxygen.”  And right now, we can use all the carbon dioxide removal we can get!

Scientific American considered the effects on endangered sperm whales in the area in a recent podcast.

The NOAA ship Pisces discovered a dead sperm whale on June 15—a possible victim of the ongoing oil spill in the Gulf of Mexico…

…It is known that such sperm whales feed on deepwater squid that may be impacted by plumes of dispersed oil. The endangered whales have also been spotted surfacing into the slick. How the millions of liters of oil will impact sperm whales and other cetaceans is an ongoing, unintentional science experiment.

Meanwhile, The New York Times is following researchers tracing the movement of manatees along the Florida coast. About 100 manatees (out of a total population of 5,000) migrate each summer to Mobile Bay, Alabama which means they could be swimming right into the oil.

As oil spreads into the bay, these travelers are now in danger of having their migratory routes and habitats contaminated, putting at risk a group that Dr. Carmichael believes may represent the scouts for the larger population. “So much is unknown,” she said. Manatees eat 10 percent of their body weight in sea vegetation per day. If oil clings to the sea grass, the animals could eat it, get the oil on their bodies and pass it to others by contact. After a 1983 oil spill in the Persian Gulf, between 38 and 60 dugongs, a species that is similar to manatees, died from exposure.

LiveScience focuses on those sea grasses in its recent story, “Small Creatures Will Be Oil Spill’s Biggest Victims”. The article includes an interview John Caruso, an ecology and evolutionary biology professor at Tulane University:

In particular, the cord and Spartina grasses that grow on the coast of Louisiana are crucial to the ecosystem and especially sensitive to the oil leak, Caruso said. These grasses form the foundation of the local food chain, and their root systems lessen the erosion of the small islands that protect inland Louisiana from hurricanes, Caruso said.

The other small creatures they include are phytoplankton and zooplankton:

During the spring and early summer, plankton and other organisms at the base of the food chain reproduce in the shallow water on the Gulf of Mexico. The newborn critters that result are particularly vulnerable to the oil, Caruso said.

New Scientist poses the possibility that phytoplankton are already being affected:

In fact, it’s possible – but difficult to prove at this point – that the dispersants and oil are already killing phytoplankton, which could account for low oxygen levels recorded in near-surface waters.

One thing is for certain, the oil will affect life for a long, long time. Again, from LiveScience:

As for vertebrates like birds and sharks, the major consequences of the oil leak will occur later, said Caruso. Even though birds coated in oil will die, or face difficulty after cleaning, the degradation of the food chain will cause larger problems for these animals over a longer span of time, Caruso said.

(Watch Academy researchers’ thoughts on the Gulf of Mexico wildlife and the oil spill here.)