Scientists have discovered a strange creature that once played a pivotal role in early Earth's oceans. They have discovered a microorganism that once fertilized the ocean with nitrogen.
In this latest study, he researchers examined the metagenomes and metatranscriptomes dataset from the Tara Oceans oceanographic expedition. After looking at this dataset, the researchers found a cyanobacterium that evolved during the Cretaceous period. This microorganism had no photosynthetic capabilities, which is a trait that is usually associated with similar microorganisms. Instead, this cyanobacterium provided nitrogen to a more complex cell host.
Nitrogen is hugely abundant in the atmosphere. However, getting it into a usable form for organisms is another matter entirely. Most creatures can't breathe nitrogen and instead rely on bacteria to transform atmospheric nitrogen into bioavailable nitrogen.
This particular creature that the researchers investigated evolved about 90 million years ago during a time when the oceans were starved of nutrients. While researchers knew that bioavailable nitrogen is provided by cyanobacteria, they decided to examine the relationship of this creature with other organisms.
In this case, this marine nitrogen factor is formed by a single-celled alga, called prymnesiophyte, and the cyanobacterium UCYN-A.
"This is a very important symbiotic system in marine environments because they are globally distributed, playing a significant role in today's nitrogen and carbon marine cycles," Silvia G. Acinas, who led the new study, said.
The researchers believe that the lack of nutrients during the Cretaceous period could have led to this symbiotic relationship between the algae and cyanobacteria. This, in turn, helped fertilize the ocean with nutrients which helped other forms of life grow and evolve.
The findings don't just tell researchers a bit more about this organism; they also tell researchers a bit more about the period of time in which these creatures lived. The cyanobacterium was likely instrumental in the cycle of nutrients during that time, and possibly helped the growth and the survival of the marine food web during this period. In addition, the researchers have learned a bit more about the evolution of this particular creature.
The findings are published in the March 2016 journal Nature Communications.
