Conservation Corner

Our endangered oceans—part 1

Pauline Lee

Since Malaysia Airlines Flight 370 went missing, sea trash has made global headlines. The hundreds of objects sighted off the Australian coast as possible aircraft debris turned out to be discarded fishing equipment, cargo container parts or plastic shopping bags. Sadly, there’s more garbage in the oceans than we realize.

In recent years with the aid of maps of ocean surface currents, scientists have plotted the movement of debris using time-lapse videos that show where objects dropped into the ocean will end up in subsequent years. They have discovered that objects migrate to regions known as garbage patches, huge zones where debris accumulates but floats free, circulating continuously. The Pacific and Atlantic Oceans have two patches each, north and south. The Indian Ocean’s garbage patch is centered roughly halfway between Africa and Australia. The Great Pacific garbage patch is the largest: twice the size of Texas!

These garbage patches are estimated to hold at least 269,000 tons of debris, about 90 percent of which is plastic waste. Only 20 percent of this plastic comes from marine sources, such as discarded fishing equipment or cargo ship mishaps. About 80 percent of it washes out to sea from beach litter or was carried downstream in rivers. About half of that litter is plastic bottles and most of the rest is packaging. Yet the harmful impact of plastics on the ocean is even more sinister than these garbage patches.

Actually, 90 percent of plastic in the sea is widely dispersed as degraded micro-plastics, invisible to our eyes. Such degradation is caused by wave action, sunlight, weathering and even digestion by microbes. These micro-particles are like a plastic soup, causing increasing harm to fish and other sea creatures. A 2009 research analysis of the Great Pacific garbage patch recorded 9 percent of the fish had ingested plastic particles; but by 2014, this fraction had increased to 35 percent of the fish collected. These statistics represent only the sick fish, not the ones that might have already died from plastic poisoning. Birds, sea turtles and whales are also big unintentional consumers of plastic. Even land creatures that are on the top of food chain will be affected by the micro-plastic toxins in their seafood.

Single use, throwaway plastics like bags and bottles became commonplace only after the 1950s. Now a half-century later, growing garbage patches and micro-plastics pose a serious threat to the ecology of our oceans. Because the oceans occupy 70 percent of the earth’s surface and provide half of the oxygen we breathe, we must curb this plastic pollution before the harm becomes irreparable. It is estimated that 33 percent of the plastic manufactured worldwide is used once, then discarded. Moreover, a staggering 85 percent of the world’s plastic is not recycled. For the sake of our oceans and our health, are we ready to change the way we use plastic?