Seasick The Hidden Ecological Crisis of the Global Ocean

Customer Reviews:

MAL DE MER
by Richard L. Reinert in Canada

Seasick is as poetic as informative and its author wastes little time. On page two, Mitchell describes the Great Barrier Reef: "It is a biological gold mine, more productive than tropical rainforests. Within earth's most important medium for life, the Great Barrier Reef is arguably the most important part. It is the marine equivalent of the biggest city in the world, a vast maternity ward, the lushest, most productive, and probably most complex biological system on the planet. Innumerable different types of plants and animals live here. It is an engine of evolution."

A substantial number of publications have forecast severe environmental conditions if carbon loading of the atmosphere is not greatly reduced. In Seasick, Mitchell approaches related problems in the ocean from an unusual perspective. Rather than predicting the fate of large creatures that depend on the health of the ocean like fish, whales, polar bears or dolphins and humans, she opens this important story by explaining how carbon dioxide threatens the health of the smallest marine organisms, called plankton. She calls them "the lynchpin on which life itself depends." In Seasick, she describes diving at two coral reefs with scientists from marine laboratories in Australia and Puerto Rico. There is a symbiotic relationship between coral and certain plankton. She exemplifies her concern by writing: "Over the last twenty years, living coral has been destroyed more quickly than tropical rainforests."

The one-celled plants called phytoplankton the base of the oceanic food chain. Some are so small, Mitchell says, "that 860,000 of them could fit in a teaspoon." Mitchell maintains that phytoplankton "produce about one-half of the oxygen that we and other terrestrial animals breathe." Zooplankton are similarly small animals that feed on phytoplankton and are fodder for fish and some whales. This is the start of a fascinating path Mitchell takes to build a case for the control of carbon loading. Rather than regurgitating scientific literature, she takes readers of Seasick on a two- and one-half year journey around the world and absorbs the ambience of seventeen marine studies. A reader will feel involved in the expeditions by her character studies of the scientists and their working conditions.

Mitchell visited the Great Barrier Reef of Australia, the Gulf of Mexico, coral reefs off Panama, Chinese fish farms, shellfish farmers in Zanzibar, and a coral reef in Puerto Rico. She crawled into a bathyscaphe and dove to a depth of 3,000 feet to capture sponges from a trench near Dry Tortugas. She interviewed scientists at laboratories in Halifax, Nova Scotia and Plymouth, England. She climbed the Pyrenees to examine the history of cataclysmic climatic changes. More often than not, Mitchell pitches in to help the scientists and describes their successes as well as the unwelcome disappointments, sometimes detailing their anxieties, like a biologist who, while waiting for coral to reproduce, excitedly taps her foot more and more rapidly.

Much of Seasick revolves around the affect of modern civilization on the growth of plankton. She visits the Plymouth Marine Laboratory, calling it "Plankton Central." Jerry Blackford, one of the scientists there, runs computer simulations of ocean acidification caused by carbon dioxide absorbed from the atmosphere. His models predict that by 2050, the acidification of the ocean will be greater than any time in the previous twenty million years. If right, he says, "The oceans' life forms will be disconnected from their own evolutionary heritage." Plankton regulate the capacity of the ocean to absorb carbon. If they were to decline because of an increase in the acidity of sea water or if calcium becomes insufficient for their growth, she asks, "how will the effects of such a change cascade through the fiendishly intricate ocean system?"

Oxygen from phytoplankton enters the atmosphere and utilizes carbon dioxide from the atmosphere. However, plankton can utilize a limited amount of carbon dioxide. The excess becomes carbonic acid and inhibits growth of the plankton. Since industrialization, the concentration of carbon dioxide in the atmosphere has increased from 280 to 387 parts per million. At this pace, Mitchell says that by mid-century, it will become troublesome at a critical level of 450 parts per million. Acidic surface waters will become even more inhospitable to plankton and their hosts like the coral reefs, which will be further threatened by a rise in sea level. Mitchell postulates that all this will cause the extinction of a quarter of the earth's creatures. It is not clear whether she means biomass or the number of species.

Seasick alerts us to 400 "dead zones" in the ocean. A large one in the Gulf of Mexico occupies a surface area of 17,000 square meters in which no live fish are found. Mitchell calls it a blob. Unlike a blob in sci-fi films, it is nearly lifeless. There are also growing layers of methane and hydrogen sulphide in stagnant parts of the global ocean created by bacteria that feed on dead plankton and other organic substances that have sunk to the bottom. Methane is a very effective greenhouse gas. She says some scientists wonder, what if the stuff should "burp" to the surface. To her credit, she quotes Yale geophysicist, Mark Pagani, "It was a very sexy idea, and it's had its day." Blobs and burps aside, Mitchell eloquently makes the point that populations of marine animals, the ocean's valuable source of protein, have declined greatly since humans started to cast their lines and nets into the sea and collect shellfish at low tide. Over-fishing is blamed, but Mitchell's concern is the health of the smallest plants and animals, the plankton. It is on them that all life depends.

So, while many people and governments reluctantly admit that greenhouse gasses have caused a profound atmospheric effect or "climate change," Seasick warns of potentially disastrous effects on life in the sea, where it began. As one who has always been in love with the sea, I was impressed by Mitchell's integration of philosophy, science, and history. One of her observations is the most challenging: "In all of humanity's 150,000-year history, it seems to me that this is the moment to harness the human gift of being able to plan."