Saltwater covers slightly more than two thirds of the Earth’s surface, about 70 percent. Although we divide this area up into geographically based seas and oceans and give them names, almost all of it is intrinsically interconnected. The naming divisions we give are for our own convenience and solely within our conceptions, they have no actual relevance to its world encompassing reality.
Chemical exchanges occur continuously at the surface of the seas, between the saltwaters of the oceans and the gases (air) of the atmosphere. While we may not often consider this, if we do at all, it takes little thought to realize that this is obvious. As such, any changes in the composition of either the sea’s waters or the atmosphere’s gases will influence and affect this exchange.
Since the beginning of the Industrial Age we have been steadily increasing the amount of carbon dioxide in our atmosphere. The amount of carbon dioxide in our air has increased from approximately 280 parts per million volume (ppmv) in pre-industrial times to around 380 ppmv now. The current level is higher than at any time in the last 400,000 years as determined by examining fossil air bubbles in ice core samples extracted from the Antarctic. Recent studies of fossil remains indicate that the carbon dioxide in the Earth’s atmosphere may have been as much as 20 to a 100 times greater than it is now 1.4 billion years ago. However, is that significant to our current situation? We have evolved to live now, not then.
Research indicates that as much as 50 percent of the carbon dioxide we have emitted into the atmosphere has been absorbed by the seas. So if this hadn’t occurred, the carbon dioxide levels in our atmosphere and their possible impacts on global temperature and therefore climate change could have had a far more devastating impact on global human society than that which has already occurred in recent years.
The sheer volume of saltwater in the Earth’s oceans and its inherent ability as a chemical buffer, able to absorb significant amounts before being affected, means that this absorption has only lowered the pH level by about 0.1 so far. The pH scale is used in chemistry to measure the acidity or alkalinity of substances. It ranges from 0 to 14 with 7 the neutral middle point. Distilled water, for example, is neutral, measuring 7 on the pH scale. The lower the number under 7 the more acidic a substance is, the higher the number above 7, the more alkaline a substance is.
The surface waters of the seas are slightly alkaline, measuring on average 8.2 on the pH scale, with a local variance of plus or minus 0.3 dependent on sea depth, closeness to land and a few other factors. Unprocessed human sewage spills and industrial waste chemical discharges not being an insignificant factor in some areas. Areas notable for their reduced marine life.
The world’s oceans in and of themselves are not threatened or even bothered by acidification, they are non-organic after all. The marine organisms that live in them are. Of all the species of organisms that have ever lived throughout the history of the Earth, 99.9 percent are extinct. Quite simply, organic life is not as hardy as we may presume. Those unable to adapt quickly enough to changing circumstances or environmental conditions die out.
The problem the marine species face is not that the waters they live in and many obtain their oxygen from are becoming more acidic, it is the pace of that acidification process. Carbon dioxide is absorbed from the atmosphere and becomes carbonic acid in seawater most easily in colder waters, in the Southern and Arctic Oceans. But it doesn’t stay there. Research has shown through taking seawater samples that it spreads towards the equator, concentrating in the sub-tropical regions that support the largest and most varied communities of sea-life.
Humanity has spread to inhabit most land regions of our planet, not because we are appropriately adapted to live in them, but because we adapt those environments to suit us, or build enclosures to live in that contain environments that suit our needs and desires. This separation from the constraints and demands of natural environments has reduced our ability to recognize how fundamental they are to existence. Almost all other life on the planet has to adapt to their environment rather than adapting their environment to them.
Such adaptation takes time, and even with that, is the primary cause for extinctions. A natural increase in the oceans acidity would cause numerous extinctions, but many organisms would have the capacity to adapt and overcome it. But a natural increase would occur over thousands if not millions of years, giving them the time. The current rate of increase is too fast. We can hope and we can wish, but it is conceivable that all specialist species and many of the generalist species will not be able to adapt quickly enough and therefore become extinct. All of the sea living mammals such as cetaceans (whales and dolphins) and seals, the larger fish species like sharks and marlins and sea-living birds like penguins are specialist species.
Sources:
http://www.oism.org/pproject/s33p36.htm
http://www.scar.org/articles/Ocean_Acidification.pdf
http://www.sciencedaily.com/releases/2000/01/000131080830.htm
