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.
Carl Marziali | EurekAlert!
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy