Marine algae and whale diversity

Link Between Marine Algae and Whale Diversity Over Last 30 Million Years, Study Finds

A new paper by researchers at George Mason University and the University of Otago in New Zealand shows a strong link between the diversity of organisms at the bottom of the food chain and the diversity of mammals at the top.

Mark D. Uhen, a geologist at Mason, says that throughout the last 30 million years, changes in the diversity of whale species living at any given time period correlates with the evolution and diversification of diatoms, tiny, abundant algae that live in the ocean. In the paper, published in the latest issue of Science, Uhen and co-author Felix G. Mark of Otago show that the more kinds of diatoms living in a time period, the more kinds of whales there are.

Looking at thousands of published accounts of whale fossil records, the researchers assembled the records in a database to analyze and pinpoint the various fossils. The fossil records show a direct link between the productivity of the ocean and the variety of whale fossils. Uhen says they also found a correlation between global changes and fossil variety.

"This study shows that if we look at the bottom of the food chain, it might tell you something about the top," says Uhen. "Diatoms are key primary producers in the modern ocean, and thus help to form the base of the marine food chain. The fossil record clearly shows that diatoms and whales rose and fell in diversity together during the last 30 million years."

Uhen says this is the first time that such a correlation has been shown. Though scientists in the past have tried to answer the question of how the modern diversity of whale and dolphins arise, this question has been difficult to answer. The fossil record might not truly reflect evolutionary history, says Uhen. "Is it possible that the diversity of fossils we find through geological time might really just reflect the amount of preserved sedimentary rock paleontologists can search -- the more rock there is, the more fossils we find? This comprehensive study has shown that the diversity of these fossils is in fact not driven by the sedimentary rock record."

The researchers hope these findings will encourage other specialists to look at other animals with a similar narrow ecology to see if this link translates.

Uhen is a term assistant professor in Mason's Department of Atmospheric, Oceanic and Earth Sciences and is an expert in marine mammal fossils. In the future, he hopes to conduct research on how the body size of whales changes over time, and how whales became the largest living organisms in the world.

Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by George Mason University.

Journal Reference:
Felix G. Marx, Mark D. Uhen. Climate, Critters, and Cetaceans: Cenozoic Drivers of the Evolution of Modern Whales. Science, 2010; 327 (5968): 993 DOI: 10.1126/science.1185581

Algae Turned Into High-Temperature Hydrogen Source

This image shows the process by which Photosystem I in thermophilic blue-green algae can be catalyzed by platinum to produce a sustainable source of hydrogen.

(Credit: Barry D. Bruce/University of Tennessee, Knoxville)

--------------------------------------------------------------------------------------------------

In the quest to make hydrogen as a clean alternative fuel source, researchers have been stymied about how to create usable hydrogen that is clean and sustainable without relying on an intensive, high-energy process that outweighs the benefits of not using petroleum to power vehicles.

New findings from a team of researchers from the University of Tennessee, Knoxville, and Oak Ridge National Laboratory, however, show that photosynthesis – the process by which plants regenerate using energy from the sun – may function as that clean, sustainable source of hydrogen.

The team, led by Barry Bruce, a professor of biochemistry and cellular and molecular biology at UT Knoxville, found that the inner machinery of photosynthesis can be isolated from certain algae and, when coupled with a platinum catalyst, is able to produce a steady supply of hydrogen when exposed to light.

The findings are outlined in a recent issue of the journal Nature Nanotechnology.

Bruce, who serves as the associate director for UT Knoxville's Sustainable Energy and Education Research Center, notes that we already get most of our energy from photosynthesis, albeit indirectly.

The fossil fuels of today were once, millions of years ago, energy-rich plant matter whose growth also was supported by the sun via the process of photosynthesis. There have been efforts to shorten this process, namely through the creation of biomass fuels that harvest plants and covert their hydrocarbons into ethanol or biodiesel.

"Biofuel as many people think of it now -- harvesting plants and converting their woody material into sugars which get distilled into combustible liquids -- probably cannot replace gasoline as a major source of fuel," said Bruce. "We found that our process is more direct and has the potential to create a much larger quantity of fuel using much less energy, which has a wide range of benefits."

A major benefit of Bruce's method is that it cuts out two key middlemen in the process of using plants' solar conversion abilities. The first middle man is the time required for a plant to capture solar energy, grow and reproduce, then die and eventually become fossil fuel. The second middle man is energy, in this case the substantial amount of energy required to cultivate, harvest and process plant material into biofuel. Bypassing these two options and directly using the plant or algae's built-in solar system to create clean fuel can be a major step forward.

Other scientists have studied the possibility of using photosynthesis as a hydrogen source, but have not yet found a way to make the reaction occur efficiently at the high temperatures that would exist in a large system designed to harness sunlight.

Bruce and his colleagues found that by starting with a thermophilic blue-green algae, which favors warmer temperatures, they could sustain the reaction at temperatures as high as 55 degrees C, or 131 degrees F. That is roughly the temperature in arid deserts with high solar irradiation, where the process would be most productive. They also found the process was more than 10 times more efficient as the temperature increased.

"As both a dean and a chemist, I am very impressed with this recent work by Professor Bruce and his colleagues," said Bruce Bursten, dean of UT Knoxville's College of Arts and Sciences. "Hydrogen has the potential to be the cleanest fuel alternative to petroleum, with no greenhouse gas production, and we need new innovations that allow for hydrogen to be readily produced from non-hydrocarbon sources. Professor Bruce and his team have provided a superb example of how excellence in basic research can contribute significantly to technological and societal advances."

Co-authors on the paper along with Bruce include Infeyinwa Iwuchukwu, a UT Knoxville graduate student in chemical and biomolecular engineering; Michael Vaughn, a research technician; Natalie Myers, a UT Knoxville graduate student in microbiology; Hugh O'Neill, a UT Knoxville-ORNL research professor and Paul Frymier, a UT Knoxville professor of chemical and biomolecular engineering.

Killer Algae: Key Player In Mass Extinctions

Pond covered with algae. (Credit: iStockphoto)

---------------------------------------------------------------------------------------------------

Supervolcanoes and cosmic impacts get all the terrible glory for causing mass extinctions, but a new theory suggests lowly algae may be the killer behind the world's great species annihilations.

Today, just about anywhere there is water, there can be toxic algae. The microscopic plants usually exist in small concentrations, but a sudden warming in the water or an injection of dust or sediment from land can trigger a bloom that kills thousands of fish, poisons shellfish, or even humans.

James Castle and John Rodgers of Clemson University think the same thing happened during the five largest mass extinctions in Earth's history. Each time a large die off occurred, they found a spike in the number of fossil algae mats called stromatolites strewn around the planet. Castle will be presenting the research on October 19 at the annual meeting of the Geological Society of America in Portland, Oregon.

"If you go through theories of mass extinctions, there are always some unanswered questions," Castle said. "For example, an impact – how does that cause species to go extinct? Is it climate change, dust in the atmosphere? It's probably not going to kill off all these species on its own."

But as the nutrient-rich fallout from the disaster lands in the water, it becomes food for algae. They explode in population, releasing chemicals that can act as anything from skin irritants to potent neurotoxins. Plants on land can pick up the compounds in their roots, and pass them on to herbivorous animals.

If the theory is right, it answers a lot of questions about how species died off in the ancient world. It also raises concerns for how today's algae may damage the ecosystem in a warmer world.

"Algae growth is favored by warmer temperatures," Castle said. "You get accelerated metabolism and reproduction of these organisms, and the effect appears to be enhanced for species of toxin-producing cyanobacteria."

He added that toxic algae in the United States appear to be migrating slowly northward through the country's ponds and lakes, and along the coast as temperatures creep upward. Their expanding range portends a host of problems for fish and wildlife, but also for humans, as algae increasingly invade reservoirs and other sources of drinking water.

Journal reference:
Castle et al. Hypothesis for the role of toxin-producing algae in Phanerozoic mass extinctions based on evidence from the geologic record and modern environments. Environmental Geosciences, 2009; 16 (1): 1 DOI: 10.1306/eg.08110808003
Adapted from materials provided by Geological Society of America, via EurekAlert!, a service of AAAS.