Scientists have known that scattered bits of kelp grow in the warm tropics in places where cold water wells up from below. Now, an international team of researchers has used worldwide ocean studies to predict and find tropical locations where whole forests of kelp grow.

Thick forests of kelp support lots of marine creatures and lure visitors like this Galápagos iguana.

S. Connell

The team recently found kelp forests in deep waters off the Galápagos Islands, about 600 miles west of Ecuador in the Pacific Ocean.

What’s more, a new computer model predicts that there may be many more of these rich ecosystems in tropical waters around the globe. The model has identified 23,500 square kilometers (9,075 square miles) of tropical ocean hideouts where kelp might be growing.

Kelp lives in chilly places because there’s extra nitrogen available in cold water that seeps up from ocean’s bottom. Nitrogen is an essential nutrient for the algae. Kelp also needs sunlight to grow.

Michael Graham of Moss Landing (Calif.) Marine Laboratories and colleagues used recently compiled data about the oceans to look for spots that might meet these conditions. Their model predicted that kelp would grow in all the tropical spots where it had previously been collected.

But the team’s model also predicted that kelp would be found in an area of the Philippines that almost nobody knew about. The area was mentioned in an old paper—written in Russian—that reported a few kelp specimens in that part of the Philippines. One scientist involved in the new study knew about that spot, but he kept the knowledge secret until after the model had predicted it.

In the Galápagos, Graham and colleagues also explored places where the model had predicted kelp forests might grow. The expedition had a rocky start.

The first robotic, remotely operated vehicle (ROV) that went underwater came off the line that connected it to the surface. The second ROV, which went down to look for the first one, had an electrical malfunction and lost its ability to “see”.

So, the scientists had to explore by scuba diving instead. During their first dive, they hit the jackpot. Graham reports that, “I went down, cleared my mask, and there was kelp right in front of me.”

They found abundant kelp in eight places around the Galápagos.

Along with other work, researchers say, the new study points out how much they still have to learn about ecosystems that live in the ocean’s depths.—Emily Sohn

Going Deeper:

Milius, Susan. 2007. Jungle down there: What’s a kelp forest doing in the tropics? Science News 172(Sept. 29):196. Available at http://www.sciencenews.org/articles/20070929/fob3.asp .

Sohn, Emily. 2006. Coral gardens. Science News for Kids (March 1). Available at http://www.sciencenewsforkids.org/articles/20060301/Feature1.asp .

______. 2005. Fishing for giant squid. Science News for Kids (Nov. 2). Available at http://www.sciencenewsforkids.org/articles/20051102/Feature1.asp .

______. 2004. Explorer of the extreme deep. Science News for Kids (Nov. 10). Available at http://www.sciencenewsforkids.org/articles/20041110/Feature1.asp .

Researchers have now found that microbes living under the ocean floor appear to produce propane and another gas called ethane. These microbes chew up ancient organic material, such as leaves and twigs buried in the sand, and they generate the gases as waste products.

That’s a surprise. Scientists had thought that propane and ethane could be produced only in the same way that petroleum is—by great heat applied to ancient, buried material.

Kai-Uwe Hinrichs examines a sample taken from a cylinder of sediment drilled out of the ocean floor.

Ocean Drilling Program Leg 201 Science Party

A team led by Kai-Uwe Hinrichs of the University of Bremen in Germany went on a research ship equipped with an enormous drill that dug out cylinders of sand or rock thousands of feet long. When the researchers examined these cylinders, they found traces of ethane and propane locked in the sediment.

Normally, to generate these gases, Earth’s heat cooks organic material in sand for many thousands of years. This can happen only at spots above cracks in Earth’s crust, where heat can leak out from inside Earth, and where thick layers of sediment would act like a blanket.

But the samples that Hinrichs and his coworkers had looked at contained thin layers of sediment. Some cylinders had also been obtained from places far from any cracks in Earth’s crust. So where could the gases be coming from?

Scientists already knew that microbes could break down organic material to produce a related, simpler gas called methane. So, undersea microbes were the only thing that made sense.

“When you can’t come up with any geologic source, then biology is an obvious candidate,” Hinrichs says.

The finding may someday lead to practical applications. Propane is valuable as a fuel, and ethane is used to make plastics. Pulling propane and ethane out of sediment is too difficult to be practical. But if scientists can better understand how microbes create the gases, they might be able to use the microbes’ methods to make ethane and propane directly from organic material.—J. Rehmeyer

Going Deeper:

Rehmeyer, Julie. 2006. Gassy bugs: Microbes may produce propane under the sea. Science News 170(Sept. 30):213. Available at http://www.sciencenews.org/articles/20060930/fob4.asp .

You can learn more about propane at en.wikipedia.org/wiki/Propane and ethane at en.wikipedia.org/wiki/Ethane (Wikipedia).

Cutraro, Jennifer. 2006. Microbes at the gas pump. Science News for Kids (April 12). Available at http://www.sciencenewsforkids.org/articles/20060412/Feature1.asp .

Sohn, Emily. 2006. Plant gas. Science News for Kids (Jan. 18). Available at http://www.sciencenewsforkids.org/articles/20060118/Note2.asp .

______. 2004. Drilling deep for fuel. Science News for Kids (Sept. 29). Available at http://www.sciencenewsforkids.org/articles/20040929/Note3.asp .

ScienceFairZone
Harvesting Biogas from Manure
www.sciencenewsforkids.org/articles/
20050504/ScienceFairZone.asp

First, Steve Miller of the Naval Research Laboratory and his coworkers scoured ship records for mentions of glowing seas. They found a carefully recorded sighting that dated back to Jan. 25, 1995. It had occurred in the Indian Ocean off the coast of Somalia.

A satellite image reveals the soft, white glow of a large patch of water in the Indian Ocean. The squiggly line (upper left corner) represents the coast of the African country Somalia.

Steven D. Miller/Proceedings of the National Academy of Sciences

The scientists then looked at satellite images taken of this area around that time. The images confirmed the event, and analyses showed that the glowing water covered 15,400 square kilometers (an area about the size of Connecticut). The glow appeared three nights in a row, and the patch moved with the currents.

The soft, white light, the researchers say, probably comes from an unusually large population of glowing bacteria called Vibrio harveyi, which live together with microscopic algae.

As satellite sensor technology improves, scientists hope to be able to detect glow patches as they happen. Then, investigators can race to the scene and learn more about what’s going on.—E. Sohn

Going Deeper:

Brownlee, Christen. 2005. Milky seas clarified. Science News 168(Oct. 1):213. Available at http://www.sciencenews.org/articles/20051001/fob7.asp .

You can learn more about bioluminescent bacteria and animals at www.lifesci.ucsb.edu/~biolum/ (University of California, Santa Barbara).

In remote Arctic lakes, the population changes among certain species of microscopic algae chronicle variations in climate over the past 150 years.

John P. Smol

A recent study focused on changes at high altitudes way up north from Canada to Russia. Many of the lakes were on islands in the Arctic Ocean. They were too far away from civilization for people’s activities to directly influence them.

These lakes freeze over in the winter. That makes the plants and animals that live in them very sensitive to changes in climate. If temperatures warm up even just a few degrees, algae have a longer growing season and so do the animals that eat the plant material.

To learn more about how aquatic life has changed over the years in these remote places, scientists from Queen’s University in Kingston, Ontario, took 55 samples of sediment from the bottoms of dozens of lakes.

Within the samples, they counted remains of tiny creatures including water fleas, insect larvae, and algae called diatoms. The team recorded the numbers of these lake inhabitants at different depths. The deeper the sediment, the older it is.

Counting the remains of tiny creatures, such as this diatom, can reveal what the climate was like years ago.

Kathleen Rühland

Results showed that ecosystems started to change in many of the lakes about 150 years ago. Populations of water fleas and algae-eating insect larvae increased, for example. And one type of diatom replaced another.

The researchers speculate that the shift was a result of climate change. Warming kept lakes unfrozen for a longer period each year, they say. Some species thrive in those conditions. Others do worse.

The new study didn’t look at what is causing global warming in the first place. Instead, it illustrates that minor shifts in temperature can have major effects on life around the globe.—E. Sohn

Going Deeper:

Perkins, Sid. 2005. Warm spell: Arctic algae record shift in climate. Science News 167(March 5):148. Available at http://www.sciencenews.org/articles/20050305/fob3.asp .