It all has to do with an experiment in the Indian Ocean in 2004. Scientists dumped seven tonnes of iron into an eddy in the Southern Ocean. As expected, an algal bloom followed. Scientific American describes this well:

A hunger for iron rules the microscopic sea life of the Southern Ocean surrounding ice-covered Antarctica. Cut off from most continental dirt and dust, the plankton, diatoms and other life that make up the broad bottom of the food chain there can’t get enough iron to grow.

The bloom was dominated by diatoms like the one pictured above. This group of algae are known to form large, slimy aggregates (marine snot) with high sinking rates at the end of their blooms. Indeed, after about a month, over 50% of the bloom sank deeply into the ocean, taking carbon dioxide with it as it went.

Science News quotes Victor Smetacek, lead author in the study, as saying:

“Every one atom of iron removed 13,000 atoms of carbon” from the air.

While scientists suspected this, they were never able to prove it. This is likely what happened during past ice ages. The air was cooler and drier then and carried more iron-containing dust from the continents to the ocean—lavishly supplying marine phytoplankton and removing carbon, cooling the atmosphere.

Now scientists are wondering if we can cool our warming climate by simply adding iron to the ocean. National Geographic has more on this geoengineering fix and other extreme geoengineering ideas to fight global warming. If only we spent this much energy on stopping global warming…

Image: Marina Montresor, SZN, Alfred Wegener Institute

It is known that biologically diverse streams are better at cleaning up pollutants than less rich waterways, so Bradley Cardinale of the University of Michigan created 150 miniature model streams to find out why this is.

The model streams use recirculating water in flumes to mimic the variety of flow conditions found in natural streams. Cardinale grew between one and eight species of algae in each of the mini-streams, then measured each algae community’s ability to soak up nitrate, a nitrogen compound that is a nutrient pollutant of global concern. He found that nitrate uptake increased linearly with species richness. On average, the eight-species mix removed nitrate 4.5 times faster than a single species of algae grown alone.

The reason? Niche partitioning, Cardinale said.

In the stream experiments, each algae species was best adapted to a particular habitat in the stream and gravitated to that location—its unique ecological niche. As more algae species were added, more of the available habitats were used, and the stream became a bigger, more absorbent sponge for nitrate uptake and storage.

Sound familiar? Think Charles Darwin. “People as far back as Darwin have argued that species should have unique niches and, as a result, we should see a division of labor in the environment,” Cardinale said.

This is exciting news because nitrate is an ingredient in many fertilizers and is found in surface runoff from agricultural land that makes its way into streams, lakes and coastal zones. It is a leading cause of degraded water quality worldwide.

“The primary implication of this paper is that naturally diverse habitats are pretty good at cleaning up the pollutants we dump into the environment, and loss of biodiversity through species extinctions could be compromising the ability of the planet to clean up after us,” according to Cardinale.

Image credit: Danuta Bennett

In 1888, scientists discovered that a type of algae grows inside the eggs of spotted salamanders as the embryos develop. Biologist Renn Tumilson describes the process this way on the Henderson State University website:

The alga, called Oophila amblystomatis (which means “loves salamander eggs”) can invade the membranes of the eggs and grow there.  The alga photosynthesizes and produces oxygen near the embryo where it is needed.  In exchange, the carbon dioxide released by metabolism from the embryo is just what is needed by the alga.

Scientists studying the symbiotic relationship believed the algae only existed inside the eggs. But last week, scientists speaking at the Ninth International Congress of Vertebrate Morphology in Punta del Este, Uruguay presented new findings that show that the algae are actually inside cells covering the salamanders’ bodies. As reported online by Nature, the symbiosis continues:

Moreover, there are signs that intracellular algae may be directly providing the products of photosynthesis — oxygen and carbohydrate — to the salamander cells that encapsulate them.

One of the researchers, Ryan Kerney of Dalhousie University, was staring at the eggs when he noticed the algae green “comes from within the embryos themselves, as well as from the jelly capsule that encases them.”

Where that algae come from still baffles the researchers. One possibility is that the algae are passed down from the mother. Nature gives another possibility, too:

Because salamanders can re-grow limbs, almost all the cells in a grown adult retain a degree of pluripotency — that is, the specialized cells can continue to divide and change into other cell types throughout the salamander’s life.

It may be that specialized cells in these adult salamanders are able to accommodate algae inside them because the process by which they learn self-recognition is different from that of other vertebrates.

Algae have been found in similar symbiotic relationships with invertebrates like corals, but this is currently the only example with vertebrates. Scientists wonder if there could be more salamanders that hold algae so dear. According to Nature, Congress attendee Daniel Buchholz, a developmental biologist at the University of Cincinnati in Ohio, said, “I think that if people start looking we may see many more examples.”

Creative Commons image by Scott Camazine

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!

Now, because of chemicals commonly found in agricultural fertilizer and sewage, life in the Baltic Sea is faced with a new type of dead zone. A dead zone without marine life and covered in algae.

The Baltic Sea has been experiencing algal blooms, a rapid growth of phytoplankton due to an influx of nutrients. These blooms occur naturally, but on a much smaller scale. Similar to plants, algae flourish when levels of nitrogen and phosphorous are present in high amounts.  When it rains, the nitrogen in fertilizer from upstream farmland runs off into the Baltic Sea. Phosphorous by-products from sewage systems discharge also end up in it’s vast waters.

The massive explosion of algae threatens the whole marine ecosystem. As the algae blooms it starves seaweed of light. Because seaweed is essential reproduction habitat for pike and perch, their reproduction is is almost non-existent in areas where they once thrived. But these fish aren’t the only one’s to suffer. When the algae die, they land on the seabed, and feed the bacteria which consume the water’s oxygen. Without oxygen, cod, herring and other animals can’t live. Consequently, the Baltic Sea is now home to seven of the world’s ten largest marine “dead zones”.

Although the nine countries that surround the Baltic have legally agreed to clean up the Baltic sea by 2021 through a series of laws, they remain largely unenforced. As a result, the sustainability of this popular vacation resort and fishing ground remains threatened.

At a press conference today at the annual AAAS meeting, several scientists discussed the very real possibility of algae as a future super biofuel.

This is not new news. According to Al Darzins of the National Renewable Energy Laboratory, the Department of Energy looked into algae as an alternative fuel source as early as the 1980s. Budget cuts and cheap oil in the 1990s slowed the research process, but as we look to a future of renewables to halt our dependence on oil, algae has once again come into the spotlight.

Algae inhabit an amazing diversity of habitats. Algae can grow in salt water, brackish water, fresh water… But wait, there’s more! It can also grow in waste water, essentially cleaning the water while growing. And it can feed on (and clean up) the CO₂ waste from coal-based power plants. It may also be able to grow on non-arable land.

What makes this especially exciting? As researcher Ron Pate of Sandia National Laboratories simply puts it, “Algae can produce oils… and there’s a lot of promise to create quite a bit of oil from algae.”

The researchers are currently discovering which algae have higher oil content, and which might be better suited to specific locations and seasons. And, importantly, how algae biofuels can be affordable. Robert Hebner of the University of Texas believes that he can get the costs close to three dollars per gallon.

Running your car on algae biofuel won’t happen too soon, however. Along with costs, regulations and environmental risks with large scale algae production still have to be assessed.

As one of our favorite renewable energy champions, Dan Kammen of UC Berkeley, reminded us today, algae will probably just be one of many diverse and sustainable energy resources in the future.