A modern horror among maritime disasters

Press, 16 April 1980, Page 21

A modern horror among maritime disasters

By

OLIVER RIDDELL

' The names of the Torrey Canyon and Amoco Cadiz have joined the Titanic, the Hesperus, and a few others, in the annals of maritime disasters. But the Torrey Canyon and Amoco Cadiz stand for a new horror of the oceans — oil spills. Tanker spills account for a third of the 6.1 M tonnes of oil thought to enter the marine environment annually according to a marine biologist Dr Philip Tortell. The rest finds its way into the ocean from natural seepage and atmospheric fallout, and by way of rivers and urban sewers.

These slow and constant discharges are being recognised for their negative effect on the seas, but it is the sudden massive tanker spills and well blowouts which attract the most attention and whose effects are most instantly and obviously manifest. (Today, they are commonplace. An oil well in the Gulf of Mexico discharged oil for months before. being brought under control recently, and tanker accidents happen with alarming regularity.)

Oil is a very visible, black, viscous liquid. It floats on water and does not mix with it. It tends to form a layer on top, one single molecule thick; so a small amount covers a large area. It absorbs and sticks to clothing, skin, feathers, rocks, sand, and boats, and cannot be wiped or washed off simply. Because it is so ugly, oil spillage often leads to

hysteria and panic. When the R.A.F. had finished firebombing the Torrey Canyon off the English coast and the. last oil slicks were mopped up or dispersed, it became cruelly obvious that the efforts to mitigate the spill had compounded its worst effects many times over.

The Torrey Canyon attracted droves of the curious and ignorant, whose presence clogged the roads leading to the affected beaches, retarded moves to rescue wildlife, and led to private scenes of violence between those coping and those gawping.

A blow-out at •an off-shore drilling platform in the Santa Barbara Channel, California, released about 100,000 tonnes of black crude oil. Only a small proportion of the waterfowl taken in by an army of volunteers survived. Oiled beaches not treated with dispersants survived ecological damage better than those which had. The type of oil spilled,

i the time of the year, the weather, the hour of the i day, the state of the tides. I and a host of other ! physical factors can detert mine the degree .of damage, i The most common s physical damage caused by 1 oil is direct smothering and ’ asphyxiation. When sltells get a coating of oil their i surface area is increased . and they are more likely to be dislodged by warves. The : oil coating gives them . more buoyancy and they i are swept away. The most highly toxic fraction of oil is very : volatile, and a large proportion is liberated into the : atmosphere after a spill. As J these substances are also water-soluble, they disperse of their own accord. This means that apart from poisoning by direct contact with an .oil slick, animals can be poisoned at some distance. Eggs, larvae, and; the young of species are particularly vulnerable; older and larger animals may not be killed outright, but their pray may have been poisoned so they risk starvation, or poisoning I from the residues of their • prey in their systems. [ Oil affects the behaviour i of animals. Those that can { escape usually do, but many I animals affected by., oil be* > come confused and dis« | oriented. Birds become pre- I occupied with preening ; and so swallow ' large i . amounts of oil. Instincts of | escape, feeding; and breed-< | ' ing are distorted. Birds;are J less able to tolerate stress ! or resist infection. ’ Animals which survive j the poisons and trauma > may not survive in their r changed environment. Sea- J weed providing food and !’ shelter can be obliterated. I Heavy accumulations of oil !' in the Straits of Magellan, ’ where the Metula foundered formed an ' asphalt-like pavement be- i tween the tidal marks. Two ■’ years later this pavement i’ was still intact: the seaweeds had not returned. * Many fish lay their eggs ; in sheltered tidal mud flats, ; serving as nurseries for fish • which live in deeper waters as adults. These calm and i complex waters are the : most vulnerable to long- j term damage by oil. Dr ! Tortell says that to refer ! to a major oil spill as "an ! ecological disaster” is. not ! an exaggeration.