10% Of Ocean Photosynthesis Is Dedicated To Producing Cloud Forming Molecules

Ocean plankton blooms must protect themselves from too much sun, today ocean blooms are reduced by as much as 50%

That’s may translate into a 5% – 30+% decline in global cloud production and albedo, if so it is the largest, by far, single factor in global warming

Ecorestoration of ocean plankton pastures will bring back the fish and the cooling clouds

Ocean plankton blooms are composed of both green plants (algae) and marine bacteria, which used to be called blue-green algae, cyanobacteria.  The cyanobacters are tiny and live both by photosynthesis and feeding on nutrients from the more abundant, in terms of mass, green planktors. It has been taught that the most important role of the cyanobacters is in nitrogen fixation which provides vital nitrate to fertilize and sustain the green planktors. But many have noted that the cyanobacters release a substance called DMS that plays a major role in cloud formation.

How Nature Seeds Her Clouds

Marine clouds are by far the most powerful planetary cooling force. They are made by plankton to maintain the perfect Goldilock’s Zone. Click to read more.

Clouds begin as cloud condensation nuclei (CCNs) or cloud seeds. CCNs are small particles approximately 0.2 microns in size and can be in the form of dust, soot, sea salt, or sulfur-containing compounds. CCN particles attract and hold water molecules from the surrounding environment. This leads to the formation of cloud droplets. Individual cloud droplets collide and coalescence with one another and rapidly grow in size. Once the droplets reach approximately 1 mililiter in size, they can fall from the sky as rain.

There those biological molecules of gas still are very much attracted to water and water to them so they naturally become the heart of every raindrop and bit of cloud. Therein lies evolution and Nature’s greatest accomplishment on our blue world that is far too close to the sun for comfort. Life on this blue planet has found/invented/evolved a way to make cooling clouds, and remember the blue part is 72% of the planet!

This chart shows the 4% drop in global Albedo. Collapse of cloudiness is in lockstep with collapse of ocean pastures and their cloud producing plankton blooms.

Diving into the data is an interesting exercise it shows a 2W/m2 variation in albedo forcing over recent years. This value is significant, compared to the GHG forcing for all greenhouse gas emissions over the last century which is estimated to be just 2.4W/m2! Clouds are what were/are keeping us cool, mostly thanks to plankton pastures.

Oceans are not only the lungs of the earth, they are its most potent and important temperature control

But now results from the research group led by Roman Stocker from the Institute of Environmental Engineering at ETH Zurich show that climate scientists must pay attention above all, to bacteria living in oceans.

“We have shown the circumstances under which these bacteria release a gas that plays a central role in the formation of clouds,” Stocker says.

In masterful work, just been published in the journal Nature Communications, the researchers report on their study of the cyanobacters that feed on the metabolic products of marine phytoplankton. This term encompasses a wide variety of microscopic algae that together perform many times more photosynthesis than all land plants. That means the true lungs of the earth are not the forests, but the oceans. Some authorities estimate that 90% of the oxygen in the earth’s atmosphere is produced by ocean photosynthesis. Along with all that oxygen ocean plankton blooms produce over a billion tonnes each year of a substance called dimethylsulphoniopropionate, or DMSP for short. DMSP is one of the vital building blocks for all life in the ocean.

Smell of the sea

The means by which plankton make clouds to keep our planet cool is clearly elucidated. Click to enlarge

“DMSP satisfies 95 percent of marine bacteria’s sulfur demand and 15 percent of bacterial carbon demand,” says Cherry Gao, lead author of the study and a doctoral student in Stocker’s group. Ocean life has evolved to both produce and consume DMSP which is vital to growing more biomass. Ocean bacters have two different metabolic pathways: if they demethylate it, they use both the sulfur and the carbon; if, however, they cleave it into several small molecules, they use only the carbon—while the sulfur escapes into the atmosphere in the form of dimethyl sulphide (DMS).

“DMS is what’s responsible for the typical smell of the sea,” Stocker says.

Most importantly DMS plays a pivotal role in cloud formation as a source of cloud condensation nuclei around which water vapor can condense.

Until now, scientists did not understand what drove the bacteria to opt for one metabolic pathway or the other. Stocker’s research team genetically modified a marine bacterium of the species Ruegeria pomeroyi so that it fluoresced in different colors depending on the biochemical process it used to transform the DMSP. This enabled the researchers to show that at low concentrations of DMSP, the bacteria rely primarily on demethylation—while at high concentrations of a few micro-moles per liter, the cleavage process dominates.

The Miracle Of The Vast Size Of The Oceans

The average concentration of DMSP in seawater is only a few nanomoles per liter, that’s less than 1 part per billion. Under these circumstances, the metabolic pathway of cleavage is of negligible importance; the bacteria use the sulfur for their growth and cloud formation does not take place. “But the average—which is to say the concentration of DMSP found in a large bucket simply dunked into the sea in the conventional measurement method—tells only half the story,” Stocker says: “The other half reveals itself only on closer inspection.”

Because wherever phytoplankton blooms, DMSP concentrations can be thousands of times higher. It seems that marine bacteria have adapted to this unequal distribution of DMSP in seawater. If they grow in the direct vicinity of the microscopic algae, they start to cleave the DMSP.

“So the extent of cloud formation may ultimately also depend on the details of the interaction of algae and bacteria in the sea,” Stocker says.

Ocean Pastures are the Hot Spots

The authors propose that the concentrations of DMSP that are most relevant for the bacterial production of DMS, and ultimately for global sulfur cycling and for the production of DMS-derived cloud condensing nuclei, may not be the levels present in bulk seawater, but instead those existing in microscale hotspots. This points to the importance of understanding the character of DMSP  ecology in hotspots compared to the bulk seawater.  This emphasizes the need to develop more realistic ocean pasture ecology understanding which amongst its many benefits will be enabling the quantification and characterization of this ubiquitous and important marine compound.

Read more on plankton cloud seeding at https://microbialmenagerie.com/the-unseen-cloud-makers-from-the-ocean/