Researchers discover feedback mechanism in photosynthesis that protects plants from damage by light |

This new knowledge could have important repercussions on the
quest to improve photosynthesis for more sustainable agriculture |

Textbook: Bicarbonate is formed when carbon dioxide dissolves in water, so its concentration
is related to the amount of carbon dioxide in the local environment. As well as low carbon dioxide levels causing electrons to build up and trigger the release of bicarbonate, the study also suggests the possibility that the level of carbon dioxide itself in the local leaf environment could
impact on the bicarbonate binding. "This is such an intuitive feedback mechanism at the heart of biology that I think it will go into school textbooks," said lead author, Professor Bill
Rutherford FRS from the Department of Life Sciences at Imperial.

"Now that we understand this new mechanism in the lab, the next step is to define when it kicks in out there in the field - not to mention the forest, greenhouse, plant pot, sea, lake and pond."

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Traces of the First Stars in the Universe Possibly Found

"The reason why we care [about the first stars] is intricately related
 with the air we're breathing right now," study co-author John O'Meara,

 of Saint Michael's College in Vermont, said last week at a press  conference at the 227th Meeting of the American Astronomical  Society in Kissimmee, Florida.
 "Early on in the universe, we did not have
 heavy elements [such as oxygen] at all."                  
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Photosynthesis has unique isotopic signature |

Photosynthesis leaves behind a unique calling card, a chemical signature that is spelled out with stable oxygen isotopes, according to a new study in Science. The findings suggest that similar isotopic signatures could exist for many biological processes, including some that are difficult to observe with current tools.

"We've found a new type of biosignature," said co-lead author Laurence Yeung, an assistant professor of Earth science at Rice University. "We show that plants and plankton impart this type of biosignature on the oxygen they produce during photosynthesis. "Yeung, who joined Rice in January, conducted the study with colleagues at the University of California, Los Angeles. Isotopes are versions of an element that differ in their atomic weights. For example, most oxygen atoms contain eight protons and eight neutrons and are represented by the symbol O-16. More than 99.9 percent of Earth's oxygen is O-16, but two heavier oxygen isotopes exist in trace amounts: O-17, which contains one extra neutron, and O-18, which has two extra.

"Looking at oxygen through the lens of clumped isotopes will give us a lot of new information about how oxygen is made and consumed by plants," said study co-lead author Jeanine Ash, a graduate student at UCLA. "I'm very excited about what this approach holds for the future." Read More | Isotopes of oxygen | There are three stable isotopes of oxygen that lead to oxygen (O)
having a standard atomic mass of 15.9994(3) u. Also 10 unstable isotopes have been characterized.
Using stable isotopic analysis, Laurence Yeung, Jeanine Ash, and Edward Young discovered that plants and plankton impart a unique biosignature on the oxygen they produce during photosynthesis. Credit: Doug Rumble Continue reading |

Can small land areas actually influence the composition of the atmosphere on the planet |

Each year in the Northern Hemisphere, levels of atmospheric carbon dioxide (CO2) drop in the summer as plants inhale, and then climb again as they exhale and decompose after their growing season. Over the past 50 years, the size of this seasonal swing has increased by as much as half, for reasons that aren't fully understood.

 

"The fact that such a small land area can actually affect the composition of the atmosphere is an amazing fingerprint of human activity on the planet."

 

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Photosynthetic biochemical reactions at night |

Cells often face low-oxygen conditions at night, when there's no photosynthesis releasing oxygen into the air and all photosynthetic and non-photosynthetic organisms in the environment are respiring oxygen. When this happens, some organisms such as the single-cell alga Chlamydomonas are able to generate cellular energy from the breakdown of sugars without taking up oxygen. Photosynthesis is probably the most well-known aspect of plant biochemistry. It enables plants, algae, and select bacteria to transform the energy from sunlight during the daytime into chemical energy in the form of sugars and starches (as well as oils and proteins), and it involves taking in carbon dioxide from the air and releasing oxygen derived from water molecules.  Read More:

Without photosynthesis or oxygen, basically all recognizable life that we see in our landscape would be gone |

A world without plants would be a world without oxygen, uninhabitable for us and for many creatures. We know plants release oxygen by absorbing carbon dioxide and breaking down water using sunlight through the process of photosynthesis. However, we know little about the mechanics of how plants create oxygen during photosynthesis. A breakthrough that will help advance our understanding of this critical ecological process was made recently by scientists at LSU.

"Without photosynthesis or oxygen, basically all recognizable life that we see in our landscape would be gone: no animals, no plants," said Terry Bricker, Moreland Family Professor in LSU's Department of Biological Sciences.                                                  Read More |

Geologists confirm oxygen levels of ancient oceans...

"More than 2.5 billion years ago, there was little to no oxygen in the oceans, as methane shrouded the Earth in a haze," says Lu, a member of Syracuse University's Low-Temperature Geochemistry Research Group. "Organisms practicing photosynthesis eventually started to overpower reducing chemical compounds [i.e., electron donors], and oxygen began building up in the atmosphere. This period has been called the Great Oxidation Event. "Using a novel approach called iodine geochemistry, Lu, Zhou and their colleagues have confirmed the earliest appearance of dissolved oxygen in the ocean's surface waters. 

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