Our first week of cruising is drawing to a close. We have ridden the Agulhas Current, pushed by its southwesterly flow, sometimes in excess of 2 meters per second, boosting our ship’s speed to more than 16 knots, well above its rated top speed of 15 knots. On Tuesday, our second evening out, the powerful current with 2-3 meter opposing waves posed a challenge to the ship, but skillful maneuvering kept operations smooth and successful. An operational check of the systems we’ll be working with came off well, as did the initial test CTD (conductivity/temperature/depth) station in 1200 meters of water. We’ve accomplished chemical and physical sampling as scheduled, and shipboard analytical equipment is functioning well. We are feeling very optimistic and getting used to conditions. The following blog post offers some introductory information and some reasons for the IPY work we have begun and will be continuing over the next few weeks.
If we live far from the coast, we tend to feel no true connection to the ocean, nor any real need of it. Many of us in our youth, and some of us in our maturity, think of the ocean mainly as a recreation area. We may notice its water is not as clear and clean as when we swam in it as a child. Now there’s more refuse washed up or thrown down on the beach and washing up on shores all over. Some think of and use the ocean, especially its deep waters, as a disposal site for all kinds of waste material. Our oceans, like American stand-up comic Rodney Dangerfield, “don’t get no respect.” We’d like to change that. Because in such simplistic ways of thinking, we couldn’t be further from reality.
The ocean, in actuality, is much more than most folks realize. Healthy oceans are vital to every man, woman, and child on this earth; they enable our existence. Oceans are very complex and continuously affect the rest of the world in a variety of ways. Take climate for starters. Covering two thirds of earth’s surface and having a density much greater than the atmosphere, our oceans play an enormous role in global climate. Few citizens are aware that gases constantly exchange at the air/sea interface and that carbon dioxide goes into the ocean — a great deal of it.
About a third of all the anthropogenic carbon dioxide (human-produced, as in fossil fuel burning or tropical forest clearing/burning) has been taken up by the ocean, buffering to some extent the effects of rising atmospheric carbon dioxide. Some of the carbon is cycling briefly through chemical and biological ocean processes and may soon return to the atmosphere. Some is being sequestered (isolated from other planetary processes) for as long as hundreds of millions of years in the deposition of ocean sediments that, over geological time, will compact into limestone.
While ocean uptake of atmospheric carbon dioxide helps relieve the increasing anthropogenic carbon dioxide burden of our atmosphere, increased incoming carbon dioxide makes ocean water more acidic. That poses an array of risks to ocean functions most of us take for granted. But these functions are a vital part of our life support system. An example of risk most people can relate to is destruction of coral reefs through dissolution of their calcium carbonate skeletal structure. We think of coral reefs first as beautiful, but they underpin complex ecosystems and productive fisheries. That’s just one vital ocean function. There are more, among them many we have not yet even recognized.
The project we are working on here is driven by a need for enhanced knowledge about carbon dioxide in the ocean. Closing knowledge gaps will help climate modelers improve forecasting skill for oceans and global climate. Concurrent hydrographic, alkalinity, oxygen nutrient, and tracer measurements will provide needed information about anthropogenic carbon in the ocean, its movement between ocean basins, and inter-hemispheric exchange. We are learning by doing as we contribute to the existing body of knowledge. Lessening current knowledge gaps boosts our understanding of oceans’ functions. Increased understanding of these functions enables us to treat our oceans with the care and respect they need to remain healthy and support us and their own natural ecosystems.
We’re delighted to have this opportunity to share our at-sea impressions and photos with you during the coming weeks. We hope you will find our shipboard experiences informative and enjoyable.