Walking the Plank(ton)

The extinction threat stemming from the rapid decrease of rhinos, elephants, and some other large, highly visible animals has received plenty of publicity.

By comparison, much less attention has been paid to the even more concerning decline of the largely microscopic plant and animal organisms floating near and on the surface of the oceans.

Make no mistake, loss of familiar species such as elephants and sharks would be a global tragedy, not to mention a blow to the planet's rich biodiversity that nurtures healthy, productive ecosystems. But these well-publicized large species are at the top of the food chain. Eradicate them and ecosystems will be thrown out of kilter. The way will be paved for the unchecked proliferation and domination of nuisance animal and plant species that would make for a very inhospitable environment.

Still, the potential for damage is even greater with the loss of tiny sea organisms known as phytoplankton (plants) and zooplankton (animals). They are at the base of the food web that supports all oceanic marine life. Were they to be massively depleted, the risk would increase for collapse of the current marine ecosystem, with serious long range ramifications for the human race. Decimation of the plankton population would produce a ripple effect up the food chain that would doom most sea life to famine and eventual extinction. Coastal societies that depended on oceanic fish for sustenance would also face starvation unless they could find a suitable substitute for their basic diet.

But that is just the half of it. Scientists calculate that plankton has been reduced by more than 40 percent since 1950 and is disappearing at approximately one percent annually. If this pace persists, it would threaten the integrity of our atmosphere. Plankton is estimated to supply half of the planet's oxygen and is an important absorber of airborne carbon dioxide. Severe depletion of plankton populations would leave more carbon in the air and undoubtedly escalate global warming.

Mankind appears to be the main culprit behind the plankton decline. These tiny organisms have had difficulty adjusting to the increase in water temperatures from human-generated global warming. Moreover, the increased concentration of carbon descending from the atmosphere has at times overwhelmed the planktons' absorptive capacity. As a result, ocean acidity has risen to levels that some types of plankton cannot well tolerate.

We must not allow planktons' size lull us into an "out of sight, out of mind" response to their plight. Let these miniscule marine organisms provide us another incentive--and a profound one at that--to curb carbon emissions from the burning of fossil fuels.