The answer is not necessarily “both.” According to a study published online this week in PNAS Early Edition, the explosion of species at the tropics has much more to do with warmth than with light.
“The diversity was unrelated to productivity (from photosynthesis), but it was strongly related to temperature,” said University of Southern California biologist Jed Fuhrman, who led a group that analyzed bacterial samples from warm and cold oceans.
Fuhrman’s group found far greater diversity in samples taken near the equator. In particular, samples from low-productivity waters still contained many bacterial species, suggesting that photosynthesis has little influence on diversity.
Many researchers have tried to separate the influence of temperature and sunlight, Fuhrman said, but have found it hard to do by studying higher organisms.
Bacteria are ideal subjects because of their wide distribution and the recent availability of genetic fingerprinting, he added.
The question of what drives diversity is important to biologists who seek to uncover the basic rules governing life.
“Is diversity ruled by fundamental laws, and if so, what is the basis of them?” Fuhrman asked.
The so-called kinetic law links the rates of metabolism, reproduction and many other biological processes to the motion of atoms and molecules. Such motion increases with temperature, presumably speeding up the biological processes.
Fuhrman calls this “the Red Queen runs faster when she is hot” hypothesis.
Productivity also is thought to promote diversity by increasing the food supply. This is “the larger pie can be divided into more pieces” hypothesis.
The two hypotheses may both be valid, Fuhrman said, but his group’s results show that “the kinetics of metabolism, setting the pace for life, has strong influence on diversity.”
Biologists have known for centuries that animal and plant biodiversity is greatest at the tropics, though they have not agreed on whether temperature or productivity was the cause.
The Fuhrman group is the first to show that bacteria follow the same pattern. And as the PNAS study shows, bacteria are useful vehicles for probing the causes of biodiversity.
Fuhrman, holder of the McCulloch-Crosby Chair for Marine Biology in the USC College of Letters, Arts and Sciences, has been studying bacteria since the early 1980s, when new instruments and techniques greatly improved scientists’ ability to identify microbial species.
Since then, marine biologists have realized that bacteria play a dominant role in the oceans. More than half the carbon dioxide respired by marine organisms comes from bacteria, Fuhrman said. Bacteria also comprise most of the diversity on earth, control vital biogeochemical cycles, and form an integral part of the food chain.
“I study them because, even though they’re invisible, they’re incredibly important,” Fuhrman said.
Fuhrman was first author on the PNAS paper. His co-authors were USC graduate students Joshua Steele, Ian Hewson, Michael Schwalbach and Mark Brown; University of Oregon, Eugene biologist Jessica Green; and last author James Brown, from the University of New Mexico, Albuquerque.
The National Science Foundation supported the group’s research.
Carl Marziali | newswise
Robocabs: The mobility of the future?
25.06.2019 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
Self-organising system enables motile cells to form complex search pattern
07.05.2019 | Westfälische Wilhelms-Universität Münster
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
25.06.2019 | Architecture and Construction
25.06.2019 | Life Sciences
25.06.2019 | Power and Electrical Engineering