An international team of scientists, including geochemists from the University of California, Riverside, has uncovered new evidence linking extreme climate change, oxygen rise, and early animal evolution.
This photo shows researchers studying exposures of the Doushanto Formation. Located in China, the formation is most notable for its scientific contributions in the hunt for Precambrian life.
Credit: M. Kennedy
A dramatic rise in atmospheric oxygen levels has long been speculated as the trigger for early animal evolution. While the direct cause-and-effect relationships between animal and environmental evolution remain topics of intense debate, all this research has been hampered by the lack of direct evidence for an oxygen increase coincident with the appearance of the earliest animals — until now.
In the Sept. 27 issue of the journal Nature, the research team, led by scientists at the University of Nevada, Las Vegas, offers the first evidence of a direct link between trends in early animal diversity and shifts in Earth system processes.
The fossil record shows a marked increase in animal and algae fossils roughly 635 million years ago. An analysis of organic-rich rocks from South China points to a sudden spike in oceanic oxygen levels at this time — in the wake of severe glaciation. The new evidence pre-dates previous estimates of a life-sustaining oxygenation event by more than 50 million years.
"This work provides the first real evidence for a long speculated change in oxygen levels in the aftermath of the most severe climatic event in Earth's history — one of the so-called 'Snowball Earth' glaciations," said Timothy Lyons, a professor of biogeochemistry at UC Riverside.
The research team analyzed concentrations of trace metals and sulfur isotopes, which are tracers of early oxygen levels, in mudstone collected from the Doushantuo Formation in South China. The team found spikes in concentrations of the trace metals, denoting higher oxygen levels in seawater on a global scale.
"We found levels of molybdenum and vanadium in the Doushantuo Formation mudstones that necessitate that the global ocean was well ventilated. This well-oxygenated ocean was the environmental backdrop for early animal diversification," said Noah Planavsky, a former UCR graduate student in Lyons's lab now at CalTech.
The high element concentrations found in the South China rocks are comparable to modern ocean sediments and point to a substantial oxygen increase in the ocean-atmosphere system around 635 million years ago. According to the researchers, the oxygen rise is likely due to increased organic carbon burial, a result of more nutrient availability following the extreme cold climate of the 'Snowball Earth' glaciation when ice shrouded much of Earth's surface.
Lyons and Planavsky argued in research published earlier in the journal Nature that a nutrient surplus associated with the extensive glaciations may have initiated intense carbon burial and oxygenation. Burial of organic carbon — from photosynthetic organisms — in ocean sediments would result in the release of vast amounts of oxygen into the ocean-atmosphere system.
"We are delighted that the new metal data from the South China shale seem to be confirming these hypothesized events," Lyons said.
The joint research was supported by grants from the National Science Foundation, the NASA Exobiology Program, and the National Natural Science Foundation of China. Besides Lyons and Planavsky, the research team includes Swapan K. Sahoo (first author of the research paper) and Ganqing Jiang (principal investigator of the study) of the University of Nevada, Las Vegas; Brian Kendall and Ariel D. Anbar of Arizona State University; Xinqiang Wang and Xiaoying Shi of the China University of Geosciences (Beijing); and UCR alumnus Clint Scott of United States Geological Survey.
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.
Iqbal Pittalwala | EurekAlert!
Hurricane Harvey: Dutch-Texan research shows most fatalities occurred outside flood zones
19.04.2018 | European Geosciences Union
Root exudates affect soil stability, water repellency
18.04.2018 | American Society of Agronomy
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy