Cruise Log: August 5, 2008
| Captain Murile has seen a lot of our oceans these past 2 decades or so. Here he reflects on something many of us have noticed on this cruise and like the Captain, we are rather concerned that we humans are making negative impacts on one of the last relatively pristine places on this planet, the open ocean. | |
Gyres: The Toilet Bowl of the Oceans During our last transect between “Lucky Strike” and “Lost City” we crossed a section of the North Atlantic gyre. Gyres are usually associated with High Pressure weather systems that drive the winds that cause the ocean’s currents to circulate clockwise in the Northern Hemisphere along with the Coriolis effect. The Gulf Stream, flowing northeast, brings warm water from the Caribbean and East Coast of the US across the North Atlantic, then splits to Europe towards the North and turns into the Azores Current, flowing southeast, then joins the Canary Current heading further south, when it encounters the North Equatorial Current flowing westward across the Atlantic, that in turn feeds the Gulf Stream again completing the circulation. The currents cause the gyre to circulate around the edges of the ocean drawing into its center whatever trash is discarded from the shores and passing ships, much like when you flush a toilet. The Coriolis effect causes surface waters to pile up in the centers of gyres, thus, with nowhere else to go but down, they are typically regions of downward motion of water (downwelling). Because of this they are usually characterized by low biological productivity/low chlorophyll as little or no nutrients are brought up to surface waters to stimulate phytoplankton growth and start the chain of life (as occurs in coastal regions). The water is a beautiful deep purple blue that is so clear you think you could see all the way to the bottom. Unfortunately clear water usually means not much in the way of visible life. There are concerns that these relatively dead zones are expanding due to global warming and pollution. While we did not see many life forms during our transect we did see literally tons of plastic along our route including plastic bags, plastic bottles, shoes, six pack holders, long line fishing gear, broken pieces of fishing nets. Seeing all the plastic for 3 days makes you realize what a severe impact we have had on the ocean. It is quite depressing to realize that all that trash will still be circulating around the ocean long after my great, great grand children are long gone. Aboard Revelle we have a strict waste management policy that includes separating out all of our plastic so that no plastic is discarded into the ocean. Joe Juhasz, an Ordinary Seaman on our ship, goes around the ship daily collecting and separating out all the waste we generate insuring that no plastic is thrown over the side. There has been a lot of publicity recently about whole cities going “bag-less”. I find this a much needed step into slowing down the contamination of our planet and turning our oceans into a toilet bowl. |
Map showing ship's track and the North Atlantic Gyre
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Jonathan Alveraz at the ships incinerator |
Eddie and Rick with Flotsam |
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