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Crisis in our seas,
This review is from: Ocean of Life (Hardcover)
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After a short review of how the oceans were created, the author looks at the evidence that fish catches have declined greatly in both numbers and fish size. He then discusses the role played by winds and currents in recycling water between the warmer shallow surface layer and the vastly deeper colder layer, and how this crucially affects the oxygen content of the seas. There follow several chapters analyzing the problems that have accumulation over the long period of man's exploitation of the sea as a source of food.
Rising CO2 levels have led to increased acidification of seawater, with disastrous effects on those organisms that have carbonate shells, the evidence for which is clear from the destruction of many coral reefs. Included are species of plankton, a vital source of food for numerous aquatic animals. Global warming has contributed to rising sea levels, leading to serious risk of long-term flooding for many low-lying areas, including major cities such as New York, Istanbul and Tokyo. Oil spills, discharge of chemical waste, and the run-off of agrochemicals directly pollute the sea, resulting in an increasing number of areas devoid of oxygen and unable to support aquatic life. One of the worst pollutants is plastic, which often ends up in the guts of fish and kills them. Gigantic `garbage patches' of plastic bags, fishing lines, polystyrene cups and other detritus now exist in several areas of the ocean. Although virtually indestructible, plastic does eventually fragment into microscopic particles. These are now found in the flesh of numerous sea organisms, and via them into our own bodies. Its long-term effects are unknown. Subtler is undersea noise, which has vastly increased following the replacement of sailing ships by powered vessels, oil exploration, and the use of sonar by navies. Even `green' offshore wind farms produce a continuous hum. Noise pollution is a serious problem for the many species that use sound to find food and mates, and to avoid predators. If all this were not enough, there are vastly more viruses in the sea than any other form of life there, but what effect all these changes will have on them is unknown.
Nature has survived many upheavals in the past, including times when the seas were far more acidic and the atmosphere contained far more CO2 and methane, and perhaps life will adapt in the long term. However, the difference now is the complexity of the changes and the speed at which they are happening. We cannot continue indefinitely to `spend our capital' by `moving elsewhere' when a resource is exhausted. The author believes that we could be on the cusp of the sixth great extinction of huge swathes of life on the planet. The last third of the book looks what actions might enable us to avoid this catastrophe.
One is fish farming, which has grown greatly in recent years. But the headlong rush into aquaculture has itself produced many problems and they will need better management if they are not to produce more harm than good. At the same time, far more effort will be needed to control chemical pollution, and a major effort must be made to start the long process of cleaning up currently polluted seas. Most important of all is the need to greatly increase the area of the sea that is protected from fishing, particularly destructive dredging. The fishing industry, backed by weak politicians, is woefully blind to the ample evidence that protection rapidly increases fish stocks in nearby areas, and leads to increased catches both in numbers and size of fish. There is no lack of much more ambitious eco-engineering schemes, but the author rightly believes we should be wary of tinkering with the global ecosystem while they remain unproven.
There are perhaps too many details here that can be absorbed on a single reading, but even so the big picture comes across very clearly in this well written thought-provoking book, which is illustrated by a collection of stunning photographs. It ends with a stirring call to action, and although any measure will be difficult to implement, even if there were co-operation from all countries, which is far from the case, the author remains optimistic that changes can be made. He even suggest how individuals can help. Unless we do something, eventually all of us will suffer, so the book deserves to be read by everyone.