Spring Break
After asteroid, algae recover at explosive pace
Issue date: 10/15/09
Algae blooms are capable of wiping out large swaths of marine life, consuming vast amounts of oxygen in ponds and lakes and depriving other organisms of essential nutrients. And while it is clear that algae can reproduce at a rapid rate, recent research has shown that algae grow at a truly mind-boggling pace.
The asteroid that struck Earth approximately 65 million years ago caused mass extinction among living organisms. Dinosaurs were probably wiped out because of the impact, and so was 80 percent of Earth's marine life. Previous researches had assumed that marine photosynthetic organisms took almost millions of years to recover, creating the infamous "Strangelove Ocean," where primary productivity was suppressed for a substantial interval of time.
However, recent research has pointed out that algae recovered in less than 100 years.
This ground-breaking discovery was led by Julio Sepúlveda, a geochemist and post doctorate fellow at the Massachusetts Institute of Technology (MIT), and MIT Professor of Geobiology, Roger Summons, among others. Sepulveda has studied the presence of suggestive chemicals in seabed clay since he was a graduate student at the University of Bremen, Germany.
The team studied a 15-inch layer of Fish Clay at Kulstirenden, an island in Denmark.
"We chose the place because it has an unusually thick layer of sediment from the period of the mass extinction", an MIT spokesperson said. Previous researches on the same question had only used sediments a few centimeters thick.
Algae, like any photosynthetic plant, contain certain isotopes of carbon and nitrogen, as well as certain organic compounds. Bacteria, on the other hand, contain certain isotopes of nitrogen. Using a Gas Chromatograph-Mass Spectrometer (GC-MS), the researchers could measure minute quantities of different molecules in the rock.
At the base of the clay sediment, which was formed the earliest after the asteroid's impact, there was a noticeable scarcity of stable isotopic compositions of carbon and nitrogen. These excursions suggest the post-impact extinction but initial stages of recovery of primary productivity. This observation is possibly related to the low levels of oxygen detected during the same time period, which is not favorable to algae growth.
The asteroid that struck Earth approximately 65 million years ago caused mass extinction among living organisms. Dinosaurs were probably wiped out because of the impact, and so was 80 percent of Earth's marine life. Previous researches had assumed that marine photosynthetic organisms took almost millions of years to recover, creating the infamous "Strangelove Ocean," where primary productivity was suppressed for a substantial interval of time.
However, recent research has pointed out that algae recovered in less than 100 years.
This ground-breaking discovery was led by Julio Sepúlveda, a geochemist and post doctorate fellow at the Massachusetts Institute of Technology (MIT), and MIT Professor of Geobiology, Roger Summons, among others. Sepulveda has studied the presence of suggestive chemicals in seabed clay since he was a graduate student at the University of Bremen, Germany.
The team studied a 15-inch layer of Fish Clay at Kulstirenden, an island in Denmark.
"We chose the place because it has an unusually thick layer of sediment from the period of the mass extinction", an MIT spokesperson said. Previous researches on the same question had only used sediments a few centimeters thick.
Algae, like any photosynthetic plant, contain certain isotopes of carbon and nitrogen, as well as certain organic compounds. Bacteria, on the other hand, contain certain isotopes of nitrogen. Using a Gas Chromatograph-Mass Spectrometer (GC-MS), the researchers could measure minute quantities of different molecules in the rock.
At the base of the clay sediment, which was formed the earliest after the asteroid's impact, there was a noticeable scarcity of stable isotopic compositions of carbon and nitrogen. These excursions suggest the post-impact extinction but initial stages of recovery of primary productivity. This observation is possibly related to the low levels of oxygen detected during the same time period, which is not favorable to algae growth.
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