A Sea Without Shells

By Gigi M. Campos

Spending time at the beach in Sipalay is always a welcome respite - away from the problems of city life, uncollected garbage and pollution. Walking along the shores, always gets me to think of how life is like a beach. Waves of things happen to us, some good, some bad. Do we sink or swim or end up empty and lifeless on the beach, giving up when things get tough and emptying us of hope and life like the broken shells of animals once alive? Or, are we like the shellfish sometimes swept around by waves of opinions or troubles until the tide starts to go out? Or, are we like the sand crabs who live under the sand, waiting for opportunities that could lure us from our safe little holes, then plunging out to grab whatever we can of life, love, or hope then retreating back in our holes once we think we’ve had enough of life? Or, are we like the sea gulls who fly above, enjoying the wind under our wings, diving in when we see food to eat, bobbing on the water, going with the flow of life? Or, are we like the little fish who live in the shallow waters sometimes, avoiding predators, eating when they need to, enjoying the unity of a school of other fish as they swim about exploring the currents, the underwater world, and experiencing life? 

Our oceans are becoming more acidic by the day, affecting the ability of shellfish and coral to create the shells and skeletons vital to their survival. In the 1960s, Rachel Carson came out with a book “Silent Spring” which alerted the world to the problems of the insecticide DDT in the food chain. Birds of prey were particularly vulnerable, with their eggshells becoming so thin they could no longer contain growing embryos. The threat of springtime with no birdsong catapulted the world into a new awareness of ecology and conservation. 

Forty-nine years on, a new threat is looming, this time in the sea. Once again the busy rhythm of people is causing an ecological crisis. Not as complicated as modeling global warming, not as simple as banning a pesticide, our newest planetary drama is called ocean acidification. It happens because of the connections between air, water, and shells. 

We know that human activities, particularly the burning of coal, oil, petrol and wood, have for the past 200 years increased the amount of carbon dioxide, or CO2, in the atmosphere. While these molecules float around in the air, they act like a blanket keeping Earth warm and eventually changing the whole climate. The warming effects of CO2 have been less than they could have been, however, because about a third of CO2 from the air gets mopped up by the oceans. 

What’s good for global climate change, however, is bad for the sea. When you add CO2 to sea water, it becomes more acid. And that means that the carbonate ion, CO3, gets scarcer. That might seem like no big deal, but many marine plants and animals use carbonate, along with calcium, for constructing protection and structure. 

Clams, snails, urchins, corals, some algae, and many plankton all use calcium carbonate (CaCO3) to build their shells. 

Marine ecologists have only just begun to investigate the potential problems that a more acid ocean might pose to creatures in the sea. What they have found so far is alarming. Tiny plankton, zillions of which form part of the basis of the marine food chain, are usually protected by a robust and complex ball of carbonate. 

But when you grow them in more acid conditions, these little shells become thinner and more frail. Even more alarming, experiments with corals show that under acid conditions, some do not make a skeleton. They sit there like a jelly glob with no sign of the complex architecture that makes coral reefs so diverse and so attractive to tourists - and to fish. This isn’t just a problem for squishy marine critters. Marine aquaculture and multimillion-dollar fisheries such as mussel farming are likely to be affected. 

Tourism to coral reefs is another multimillion-dollar industry, and some economies are wholly reliant on it. There is even the suggestion that a more acid ocean could be more corrosive and thus affect shipping and ports. 

Our seas are growing more acid by the day. Early estimates suggested that acidity could go up 30 per cent by the end of this century. Now scientists are warning that, in the Southern Ocean, we could be seeing measurable changes within a few decades. The effects of what we have already pumped into the air are probably irreversible. There are no practical solutions or cures - no antacid for the sea’s indigestion. The only thing we can do is to slow it down. 

Luckily, we already want to reduce carbon emissions and know we need to stop the invisible clouds of CO2 rising into the air. We already have mechanisms in place to change how we live and travel. Ocean acidification provides another, and perhaps a more urgent, reason for continuing on this path as fast as possible. 

Luckily, we still have birds of prey. That is because people cared, listened and took action. Ordinary gardeners stopped using DDT, and eventually governments also responded. Now you can’t buy DDT and you can’t spray it around. 

Geologists, who specialize in the long- term view, are beginning to call the present time a period of the anthropocene epoch. The term Anthropocene is used by some scientists to describe the most recent period in the earth’s history. It has no precise start date, but may be considered to start in the late 18th century when the activities of man first began to have a significant global impact on the Earth’s climate and ecosystems. 

It is when the activities of humans are so pervasive that they will be the dominant signal in the geologic record of our time. So far, it appears that the anthropocene will be renowned for its great extinction event - a period in which Earth became so unhealthy that hundreds of species of animals and plants ceased to be. Given that acidification is to be added to the effects of coastal pollution, ongoing development, sedimentation and over-fishing, it is not surprising that our coastal ecosystems are set to crash. 

We can choose to make a difference if we want to continue to enjoy the sight, sounds, smells and feel of the water, sun and sand... Think about all those millions of plankton making their complex and perfect skeletons. When we are on the road, we need to think about that exhaust, puffing out the back of every car, each little bit of CO2 heading into the air, into the sea, a little drop of poison for our planet. Each of us can make small differences. Think about what you can do, today, to save just one plankton, just one coral. Because a sea without shells is like a springtime without birds.*