The sea and its treasures
Sylvia Earle, Deep Sea Ocean Exploration and Research, United States
In the Philippines,
the life-sustaining
encounter between
land and sea.
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From blazing Ardour Cosmic Order came Rg Veda X, 190, |
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Facts and figures • 70.8% of the earth’s surface is ocean, or 361.3 million
km2 out of a total surface of 510 million km2. By volume, 97.957% of the water on
the planet is oceanic water and associated sea ice. |
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It is said that Alexander himself entered a colymphas [a kind of bathyscape] and was lowered to the sea bed to find out the depth of the ocean and discover the specific nature of the sea and the abyss. Aethicus Ister, Cosmographia (8th century, probably Ireland) |
In many parts of the world, ways of using the sea’s resources in harmony with ecosystems are dying out. Below, a traditional method of fishing in the Maldives.
‘How can the ocean be in trouble? It’s so huge!” The speaker, an avid fisherman, had just read an article about pollution creating a so-called “dead zone” in the northern Gulf of Mexico, and was sceptical. “I love the ocean,” he said. “But I can’t imagine that we can do much to harm a system so large and resilient. The sea seems infinite, timeless!”
My friend’s perception of the ocean has been a common one—until recently. As the waters of the world have become increasingly stressed, an awareness of their importance to humankind has come into sharp focus. Fishermen find it increasingly difficult to find once numerous species—cod, capelin, swordfish and many more. Phenomena such as the El Niño have created widespread appreciation of the role of the ocean in shaping climate and weather. Water evaporates from the sea’s surface and forms clouds that yield fresh water back to the land—and sea. About 97 per cent of Earth’s water is marine, and of the remaining 3 per cent, 97 per cent is frozen as polar ice and snow. Water, of course, is vital for life. There may be water without life, but nowhere, even in the most arid deserts and driest valleys in Antarctica, is there life without water.
The recent discovery of water on Europa, one of Jupiter’s moons, has aroused much speculation about whether life might be prospering there, perhaps associated with undersea volcanic activity, like the communities that develop around hydrothermal vents in our own deep sea. Plans are now underway to send spacecraft to Europa that can deploy a robot capable of boring through three kilometres of ice before descending into a sea that may be forty kilometres deep. Meanwhile, Earth’s ocean remains largely unexplored. We have barely begun to imagine the energy potential of harnessing the waves, the healing powers of marine bacteria or the sustainable possibility of feeding the world’s hungry through algae. A veritable treasure trove, the ocean’s greatest gift may well be the Earth’s history captured in so many forms—from the remains of a shipwreck to the yearly bands of a coral reef.
But perhaps the most astonishing thing upon entering the ocean with a face mask and flippers is the discovery that it is not just a place filled with rocks and water. It is like a soup, a special kind of minestrone, where the bits and pieces are alive! “Living fossils” are everywhere. Nearly all of the thirty-three major divisions of animals and a dozen broad categories of plants and other organisms that have existed for hundreds of millions of years are at least partially represented there; only about half are terrestrial.
Every living thing on Earth acts on the surrounding environment, initiating small but real changes. All are components of the grand machinery that makes Earth what it is: a living planet, our life support system. The immense diversity of life causes change and provides the ingredients necessary to respond as change occurs. The resilience of natural systems is remarkable, evidenced by the ability to rebound after storms, fires, collisions with comets or natural climatic swings, all the while retaining a basic framework within which living things prosper—though not necessarily the same living things.
Human rapacity
Knowing that our lives depend on keeping Earth more or less as it is in terms of life support functions, it makes a lot of sense to figure out whether the swift changes we are presently witnessing—and causing—may set in motion events with undesirable consequences. Certainly, no species in the history of the planet has been as rapacious and effective in consuming and displacing other species and entire ecosystems as our own. Our impact, some say, can be likened to that of a slow-motion comet striking earth, the repercussions gradually becoming manifest, rivalling and compounding the impact of storms, volcanoes, disease—even, it now seems, nudging the grand processes that cause ice ages to come and go.
At night, our cities glow with an otherworldly light, created by consuming millions of years of fossil wealth. Complex, naturally productive ecosystems are disappearing, to be replaced by geometrical plots bearing vulnerable single-species crops. Other changes are less obvious—the removal of millions of tonnes of living creatures from the ocean in the past century, and the addition of billions of tonnes of trash—excess fertilizers, pesticides and other noxious substances. Might such actions alter the way natural systems behave? Should we worry about the consequences of taking unprecedented quantities of wildlife from the sea?
Energy ‘middlemen’
We have perfected ways of killing the ocean’s giants and their diminutive cousins—the nine species of great whales, more than fifty kinds of “small” whales, dolphins and porpoises, and all marine turtles. Many are now endangered or threatened. Bluefin tuna weighing 450 kilos, huge halibut, cod as large as the fishermen who catch them, century-old sturgeon, large swordfish, marlin, sailfish, sharks and many other once common giants are suddenly rare. Acoustic sensors developed to find enemy submarines now locate fish, squid, shrimp and other creatures for hunters to engulf with enormous nets, some large enough to swallow a dozen jumbo jets.
Recently, the populations of more than 100 marine species listed by the World Conservation Union as threatened or endangered, sharply declined. Large populations of ocean wildlife are dwindling. The three remaining concentrations of wild creatures in the sea are now being taken to produce protein concentrate: pelagic squid, large swarms of krill, and the deep, vertically migrating midwater communities of small creatures generally known as the “deep scattering layer.”
And yet crustacea, like certain squid, are linchpins in complex ecosystems. In effect, they are the energy “middlemen,” concentrating and converting plant energy into something palatable and usable by hordes of other creatures. An example of the importance of a single crustacean species is the Antarctic krill, Euphausia superba, a translucent pinkish-red finger-long creature equipped with enormous black eyes and the wonderful ability to emit an eerie blue-green version of bioluminescence. The billions of its kind make up an essential part of the living web that prospers in the Southern Ocean ecosystem. Krill swarms are consumed by penguins, terns, gulls, seals, sea lions, squid, fish, and several species of whales whose existence depends on enormous quantities of them.
So vital is this one species to the entire Antarctic realm that it would make sense to ensure that nothing disturbs its continued prosperity. Instead, several nations annually remove thousands of tonnes of the creatures before shipping them off for conversion into high-protein food for poultry, cattle and direct human consumption.
Besides predation, many other factors undermine the abundance and diversity of marine life. It is obvious that shoreline development, construction of marinas, seawalls and jetties, cutting mangroves and filling in marshes, coupled with the impact of rivers bearing heavy loads of excess fertilizers, biocides, and sediment, have taken a toll.
How can we be sure of the impact on ocean wildlife? Despite the swift and unprecedented insights into the nature of the sea yielded by technology, most of the ocean remains unknown and unexplored, even within the depths that divers can conveniently travel—from the surface to fifty metres down. The maximum ocean depth, eleven kilometres, has been attained only once, in 1960, when two men peered for half an hour through the small porthole of the bathyscaphe Trieste. Recent additional glimpses have been supplied by cameras lowered on the tethered Japanese robot, Kaiko, but these great depths—like 95 per cent of the rest of the sea—have yet to be really seen by humankind.
An uncertain future
It is easy to disregard places we cannot see, not worry or care about creatures we have never met. As troubling as the problems are relating to obvious habitat destruction and predation, the greatest cause for concern must certainly be ignorance. Some shrug and say, “What’s the problem? Humankind appears to be doing pretty well. Look at the numbers.” After all, it took all of the time from the dawn of civilization to the year 1800 before our population barely reached a billion. Less than a century and a half later that number had doubled, and now, at nearly six billion, world population continues to climb. And yet our own future may be in jeopardy.
There are no easy answers to the question of what must be done, but there is hope that a significant “hedge” against the unknowns is coming into focus with the establishment of a growing number of marine sanctuaries in coastal areas—places comparable to national parks, wilderness areas and nature reserves on the land. More than 1,200 marine protected areas have been designated by various nations. While “protection” is far from complete (commercial and sport-fishing continue in most) and the total area is still small (a fraction of one per cent of the ocean as a whole), the actions taken thus far may reflect the beginning of a new trend that will lead to finding harmony—or at least an enduring place—within the natural systems that sustain us.
The ultimate question is, “what does all this mean to us, to our future?” Can we use our awesome power to use—not use up—the natural systems that support us? Can we overcome the greatest threat to the oceans and thus to our future—ignorance? There are many unknowns, but this much is certain: we have the power to undermine the healthy functioning of the sea that supports all life on Earth—but no sure way to heal the harm. For ages, the sea has taken care of us. The time has come for us to take care of the sea.
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A marine glossary Abyssal plain: a flat, gently sloping or nearly level
region at the bottom zone of the oceans at depths between 4,000 and 6,000 metres. |