Scientists mimic nature to study complex ocean upwelling process

September 3rd, 2008 - 2:28 pm ICT by ANI  

Washington, September 3 (ANI): A team of scientists from the Oregon State University in the US has studied the complex ocean upwelling process by mimicking nature.

The method involves pumping cold, nutrient-rich water from deep within the Pacific Ocean and releasing it into surface waters near Hawaii that lack the nitrogen and phosphorous necessary to support high biological production.

The researchers are harnessing the power of the ocean to conduct their experiments, using the up-and-down motion of waves to pump deep water to the surface.

Their next step is to create a pump that can withstand the rigors of the rugged Pacific and then see if the biology follows the physics.

According to Angelicque White, a post-doctoral researcher at Oregon State University and a member of the scientific team, Initially, the system worked and we were able to bring cold water to the surface and control the depth of its release. Now we need to work on the engineering aspect.

The scientists stress that the goal of creating artificially induced upwelling is to understand how marine microbial ecosystems respond to large-scale perturbations, a critical step if we want to understand the risks of manipulating these large ecosystems in order to solve global greenhouse buildup, said Letelier, a professor in OSUs College of Oceanic and Atmospheric Sciences.

According to Letelier, simply bringing nutrients to the surface can result in the wrong kinds of biological growth. It also can bring water enriched with carbon dioxide, which can de-gas into the atmosphere.

If youre adding more CO2 than subtracting by fertilizing the ocean, youre running the wheel in the wrong direction, he said.

The answer, according to Letelier, may be to pump water that contains specific ratios of nutrients particularly nitrogen and phosphorous to carbon dioxide by targeting different depths.

At their research site north of Hawaii, where the ocean is about 4,500 meters deep, the bottom layers of water have too much CO2 because of the decaying organisms that have sunk to the floor.

Their studies have shown, however, that water at a depth of 300 to 700 meters has the proper ratio of nitrogen and phosphorus to trigger a two-stage phytoplankton bloom.

The researchers believe that upwelling with water from that depth will first cause a bloom of diatoms, which are a common type of plankton often single-celled.

The diatoms will consume the nitrogen, leaving some amount of phosphorus in the water, which will stimulate a second-stage bloom of nitrogen-fixing cyanobacteria.

These blooms are often observed during summer months in open ocean waters, Letelier said. (ANI)

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