The Odyssey docked in Las Palmas, Gran Canaria.
Photo - Judith Scott
January 2, 2005
Odyssey Arrival in Gran Canaria
This is Judith Scott speaking to you from the Odyssey in Gran Canaria.
The Odyssey has now finished its research in the Mediterranean and is heading into the final research area for the Voyage, the Atlantic Ocean. The only way from the Mediterranean into the Atlantic is through the Strait of Gibraltar.
The Odyssey left Gibraltar in pouring rain but in perfect conditions to get through this narrow waterway that separates Spain and Morocco. Only 7.5 nautical miles wide at its narrowest point, we could clearly see the coastline of both continents, Europe on the starboard side and Africa off to port.
It is advisable for vessels to make the 30 mile passage through the Strait when the wind is blowing in the same direction as the strong current that runs from the Atlantic into the Mediterranean. When the wind is blowing hard from the east working against the three knot current, the Strait becomes a notoriously hazardous stretch of water. The current is mainly caused by the fact that the Mediterranean Sea is evaporating faster than the rivers flowing into it can replenish the loss, so the ocean is almost always pushing into the enclosed sea.
As Odyssey passed Tarifa, the southernmost point of mainland Europe, we started to detect a real change in the movement of the boat. We were about to enter the second largest expanse of water on the planet, and we could feel the boat start to heel over in the slow rolling swell of the Atlantic Ocean. Although swells are present in the Mediterranean, they grow much larger and farther apart over the vastness of the Atlantic Ocean, and the change in the way Odyssey moved was very apparent. We turned to the southwest and had the 2 meter swell hitting the starboard beam of the vessel, causing her to roll slowly from side to side, meaning the crew had to once again find their ocean sea legs.
The Atlantic Ocean is the second largest of the world's five oceans covering a total area of approximately 82 million square kilometres, equivalent to 19% of the Earth's surface. It has about 111,866 kilometres of coastline, an average depth of 3,330 metres and at its greatest width, the Atlantic is 9600 kilometres wide. It is thought the North Atlantic ocean began to open approximately 180 million years ago, separating Europe and North America and it has gradually been getting wider ever since. The South Atlantic started to open about 130 million years ago, separating South America and Africa. The Atlantic is widening at a rate of about 25 millimeters a year, spreading outwards from a line of volcanoes and mountains in the center called the mid-Atlantic ridge.
This ridge is the longest mountain chain in the world, an incredible 11,300 kilometer long and up to 4000 meters high from the sea floor. For most of its range it is under the surface, but in a few places it rises above the water, the largest of these forms the country, Iceland. It is joined to one continuous chain that stretches south past Africa, goes east across the Indian Ocean and then into the Pacific. Unlike the Pacific and areas of the Indian Ocean there are no volcanoes at the edges of the Atlantic. There are also, with one exception, no deep trenches. The wide continental shelves and relatively low coasts compared to land around the other Oceans, are typical of an ocean that is still widening.
The Odyssey will concentrate its research at the edge of the continental shelves, where the sea floor rises steeply. Presently, sea level is about 200 meters higher than the edge of the continental shelf. Where the continental shelf plunges down to the deep plains of basalt rock, averaging 3000m deep, coastal upwelling occurs. In these regions, deep, nutrient-rich waters are brought to the surface and this combination of plentiful nutrients and an abundance of sunlight create perfect conditions for Phytoplankton, the basis of the food chain in the ocean. Phytoplankton need light and nutrients to flourish, just like terrestrial plants. They are a very important part of the marine food-chain, so upwelling regions are usually full of a wide variety of marine life.
In contrast to these regions, there are areas called gyres, sometimes called the "deserts" of the ocean. The Atlantic Ocean has two large gyres, one in the north and one in the south of the ocean. The North Atlantic Subtropical gyre is to the west of the Canaries, where the Odyssey is currently situated. It starts about 10 degrees north of the equator and stretches up to about 40 degrees north, and across the ocean towards the USA. It is characterized by comparatively low nutrient concentrations. The gyres still contain phytoplankton, but this plankton is generally very small compared to the plankton that can be found in upwelling regions. Other marine life in these regions is therefore comparatively small and relatively sparse.
Although there isn't a huge amount of larger marine life in the gyres, the areas are extremely important to the global carbon cycle. The total surface area of the gyres is huge, and the plankton within them consume and produce CO2, an important greenhouse gas. Some of the CO2 in the atmosphere is "mopped up" by this plankton, so they affect atmospheric CO2 levels.
We are planning to spend the next couple of months researching around the continental shelf of the Canary Islands, a group containing seven main islands, surrounded by the deep waters of the Atlantic Ocean. The continental shelf is relatively close to shore in this area and there is an abundance of sea life known to inhabit this area, including our target species, the sperm whale.
Only three days into our research in the Atlantic the Odyssey crew were treated to a wonderful display by one of its native species, the Atlantic Spotted Dolphin. A pod of about 80 surfed the waves next to Odyssey and rode the bow wave, breaching right beside us. This lifted the spirits of the crew after three days of uncomfortable seas.
We entered the port of Las Palmas, Gran Canaria, the main island of the Canaries, after five days at sea from Gibraltar. The crew are busy provisioning and preparing Odyssey to start our research around the Canaries. We are looking forward to spending time researching these waters, looking for sperm whales.
Log written by Judith Scott.