Effect of CO2 levels on phytoplankton.
Story submitted by Don Healy
This article opens up a whole new vista into the relationship between CO2 levels, oceanic plant growth and the complex relationships that we have yet to learn about in the field of climate science. If phytoplankton respond like most plant species do, we may find that the modest increases in CO2 levels we have experienced over the last 50 years may actually create a bounty of micro plant growth in the oceans, which would in turn create the food supply necessary to support an increase in the oceans’ animal population.
At the same time, it would explain where the excess atmospheric CO2 has been going; much of it converted into additional biological matter, with only a limited existence as raw CO2.
There may well be a naturally balancing mechanism that explains how the earth was able to survive atmospheric levels of CO2 as high as 7000 mmp in past geologic history without turning into another Venus. Just surmising of course, but this fits with what we know about the response of terrestrial plants to elevated CO2 levels, so it is a plausible theory. Hopefully more studies along this line can clarify the situation.
From the article:
The diatom blooming process is described in the article by Amala Mahadevan, the author of the study and oceanographer at WHOI, as inextricably linked to the flow of whirlpools circulating the plants through the water and keeping them afloat.
“[The study’s] results show that the bloom starts through eddies, even before the sun begins to warm the ocean,” said Ms. Mahadevan.
This study explains the causation of phytoplankton’s phenology—the reasons behind the annual timing of the microscopic plant’s natural cycle—as it is influenced by the ocean’s conditions.
“Springtime blooms of microscopic plants in the ocean absorb enormous quantities of carbon dioxide, much like our forests, emitting oxygen via photosynthesis. Their growth contributes to the oceanic uptake of carbon dioxide, amounting globally to about one-third of the carbon dioxide we put into the air each year through the burning of fossil fuels. An important question is how this ‘biological pump’ for carbon might change in the future as our climate evolves,” said researchers.
WHOI describes the study as being conducted by a specially designed robot that can float just below the surface like a phytoplankton (only much, much larger). Other robots, referred to by WHOI as “gliders” dove to depths of 1,000 meters to collect data and beam it back to shore. Together, the robots discovered a great deal about the biology and nature of the bloom. Then, using three-dimensional computer modeling to analyze the data, Ms. Mahadevan created a model that corresponded with observation of the natural phenomena.
Eddy-Driven Stratification Initiates North Atlantic Spring Phytoplankton Blooms
Springtime phytoplankton blooms photosynthetically fix carbon and export it from the surface ocean at globally important rates. These blooms are triggered by increased light exposure of the phytoplankton due to both seasonal light increase and the development of a near-surface vertical density gradient (stratification) that inhibits vertical mixing of the phytoplankton. Classically and in current climate models, that stratification is ascribed to a springtime warming of the sea surface. Here, using observations from the subpolar North Atlantic and a three-dimensional biophysical model, we show that the initial stratification and resulting bloom are instead caused by eddy-driven slumping of the basin-scale north-south density gradient, resulting in a patchy bloom beginning 20 to 30 days earlier than would occur by warming.