As the recent tsunami that hit Japan shows, oceans can be really monstrous. In a darkly poetic way, it seems that the Pacific (how ironic a moniker) was pissed about all the wildlife devastation Japan has wreaked upon the Earth’s sea creatures and decided to get even. But the same oceans that have inflicted devastation upon humans over the centuries are in turn vulnerable to man’s environmental evils.
This year we have been following, and supporting, National Geographic magazine’s coverage of, and warnings about, Earth’s human population reaching seven billion. Along with that population, and the long-term growth of the world’s middle classes, comes the limitless spewing of carbon dioxide into the atmosphere and its consequent absorption by the oceans. The chemistry of the seas involves a very delicate balance of pH, the scale by which we measure acidity and alkalinity. Add CO2 to seawater and you lower its pH value, making it more acidic. Hence, NG’s April report is entitled “The Acid Sea.”
According to NG journalist Elizabeth Kolbert, our atmosphere has higher CO2 concentrations now than it has in perhaps a million years, thanks to the advent of the industrial revolution. Burning of coal, natural gas, petroleum and other fossil fuels, as well as the destruction of forests, have led to the emitting of 500 billion tons of CO2 . How much is 500 billion tons? We can quantify it, but not actually imagine it. Picture a little Smart automobile with a driver in it. Imagine 1,000 such vehicles. Now imagine one thousand clones of that group of one thousand. You now have a million. Now imagine one thousand of that group of one million. Now imagine 250 of that group of one thousand times one thousand times one thousand. That’s how much the CO2 we have added to the atmosphere weighs. And a huge portion of it is absorbed by our oceans and lakes. That cannot happen without screwing things up BIG time.
Off the Mediterranean island of Castello Araganese, vents on the seafloor emit bubbles of carbon dioxide. The CO2 dissolves to form carbonic acid. Close to these vents there is enough acid to change the chemistry of the seawater and adjacent ecosystem. Plants and animals that normally carry other organisms on their blades and shells, respectively, are barren of any such symbiotic relationships. Marine biologist Jason Hall-Spencer of England’s University of Plymouth says that acidification that has taken place near Castello Aragonese is gradually occurring across the world’s oceans. In other words, the effluent from China’s coal burning power plants and America’s tailpipes will, by as soon as 2050, be spreading who-knows-what kind of mayhem throughout undersea ecosystems.
“In the 1990s an international team of scientists undertook a massive research project that . . . showed that the oceans have absorbed 30 percent of CO2 released by humans over the past two centuries. They continue to absorb roughly a million tons every hour,” writes Kolbert.
Let’s look at some of the impacts this acidification will have. As sea life, from microscopic to enormous, adapts to changes in seawater chemistry, food webs, biodiversity, fisheries and the organisms themselves will change. Pteropods, tiny swimming snails that are a food supply for fish, whales and birds in the Arctic and Antarctic, are experiencing changes in the growth rate of their shells.
Certain organisms, called calcifers, have difficulty forming their shells and skeletons, which are made of calcium carbonate. Of great concern is the destiny of coral reefs, the breeding ground for species numbering in the millions. Could this mark the end for future Spongebob Squarepantses (sp. spungabobbi pantelone quadretto)?
Ken Caldeira of the Carnegie Institution is quoted as saying, “Corals build the architecture of the ecosystem, and it’s pretty clear if they go, the whole ecosystem goes.” In addition to acidification, corals have been threatened by warming water temperatures, which induce so-called “bleaching” that turns the corals white and kills many of them. When overfishing removes species that graze among the corals, the reefs can be blanketed with algae. Agricultural runoff then fertilizes the algae, accelerating their growth and discombobulating the reef’s ecology. Probably due to a combination of these factors, Caribbean coral cover declined by an incredible 80 percent between 1977 and 2001.
A thin layer of tiny calcium carbonate-covered animals called coral polyps covers the surface of a reef . Kolbert explains: “CO2 levels rise, carbonate ions become scarcer and corals have to expend more energy to collect them.” This retards reef growth, making it hard for them to keep up with the erosion caused by organisms that eat away at the reef’s surface. If reef growth cannot keep up with erosion, it begins to crumble. There is good reason to fear that by 2050 the world’s reefs will reach the tipping point.
We wonder what future generations will think of their antecedents who had let – or, more precisely, been the catalyst for – such a dramatic world change; a change the likes of which no human generation had ever before caused.
And it’s not just corals. There are thousands of other calcifers that carbon dioxide impacts; clams, oysters, sea stars, sea urchins, and on and on. “Changes at the bottom of the marine food web . . . will inevitably affect the animals higher up,” including their physiology. And while there have been periods in the Earth’s history when CO2 levels have been higher, the ecology of prehistoric times may have been quite different, and the current rate of change may be the essential variable that impacts most.
We must reduce our CO2 emissions. But with expanding demand on energy, a Congress hell-bent on using fossil fuels, increasing agricultural demands, and an expanding world population, the future of the seas looks bleak to us.
As journalist Kolbert puts it: “At the moment, corals and pteropods are lined up against a global economy built on cheap fossil fuels. It’s not a fair fight.”