Spotlight on marine resources on Int'l Biodiversity Day:

One ocean, many worlds of life

By Pramod DE SILVA

How inappropriate to call this Planet Earth, when clearly it is Ocean.

Arthur C. Clarke

Without life in the ocean, there would be no life on Earth. This is the simple truth. Life started there in the first place. And there’s more ‘life’ in the ocean than on land. The oceans cover more than 70 percent of the Earth, with a total area of 360 million square Kms. More crucially, the oceans constitute over 90 percent of all habitable space on Earth.

The ocean sustains life from top to bottom. The best example is phytoplankton, which produce energy through photosynthesis and release oxygen. In fact, phytoplankton releases half of all oxygen in the atmosphere. That in itself explains why oceans literally sustain all life on the planet.

The oceans will be under the spotlight this year with the UN and Member countries celebrating the International Day for Biological Diversity (IDB) on May 22 under the theme Marine Biodiversity, just weeks away from the Rio+20 Summit on Sustainable Development. The IDB also comes in the wake of the new Living Planet report by the World Wildlife Fund (WWF) which revealed that the world's biodiversity is down 30 percent since the 1970s. Marine species alone have been reduced by 25 percent.

The sub-theme for the IDB this year is 'One Ocean, Many Worlds of Life'. The sub-theme captures the very essence of the ocean, because it is a place that teems with life – possibly a million forms of it. It is home to the largest creature that ever lived on Earth – the blue whale – and the tiniest micro-organisms. However, the reality is that the world’s oceans are still mostly unexplored – we know more about the dark side of the moon than we know about the ocean. Hence, we do not exactly know how many life forms are out there in this ‘last frontier’.

Scientists are trying to figure this out. From 2000 to 2010, an unprecedented worldwide collaboration by scientists around the world set out to try and determine how much life is in the sea.

Dubbed the ‘Census of Marine Life’, the effort involved 2,700 scientists from over 80 nations, who participated in 540 expeditions around the world. By the time the Census ended, it had added 1,200 species to the known roster of life in the sea; scientists are still working their way through another 5,000 specimens to determine whether they are also newly-discovered species. The estimate of the number of known marine species is now around 250,000. The Census team suggested it could be at least a million. It is this amazing biodiversity that we have to protect.

Coastal communities

Being islanders, we have a very close relationship with the sea. It is a resource that sustains our coastal communities via fishing and contributes significantly to the economy. This holds true for much of the world. An estimated 41 percent of the world’s population of seven billion lives within 100 km of the coast. However, the fact remains that especially over the past few centuries, we have not been very kind to this life-giving resource.

Fishing has been going on for thousands of years, but today, there are more than four million fishing vessels throughout the world which ‘harvest’ over 140 million tonnes of fish every year. That averages out to17 kg for everyone in the world, but the commercial exploitation of the world’s fish stocks is so severe that it has been estimated that up to 13 percent of global fisheries have ‘collapsed.’

Many edible fish species are endangered. Between 30 and 35 percent of the global extent of critical marine habitats such as sea grasses, mangroves and coral reefs are estimated to have been destroyed. Since 1980, an area of sea grass meadow the size of a soccer pitch has been lost every 30 minutes, and almost 30 percent of all sea grass beds are estimated to have been lost.

In the Southern Hemisphere, where once there were perhaps 200,000 blue whales, there are now around 1,000. The great auk, sea mink, Steller’s sea cow and Caribbean monk seal are extinct. The vaquita, a porpoise found only in the Gulf of California, may number as few as 100 individuals.

The southern bluefin tuna and elkhorn coral are critically endangered, as are many species of sea turtles. The southern bluefin tuna has been depleted by an estimated 92 percent. As a result of over-fishing, there are areas of the ocean where some species of tuna, billfish and sharks no longer exist. This is only the tip of the iceberg.

Apart from overfishing, the oceans face many other problems. Some fishing techniques can be a harbinger of extinction for many species. For example, bottom trawl nets scrape along the floor, devastating sea bed communities. The burning of fossil fuels is causing the ocean to become warmer and more acidic. The release of harmful effluents to the ocean has a devastating impact on life forms there.

Oil spills

Oil spills too have a great impact on the ocean, coastal communities and even birds. Plastic debris can entangle, strangle and be eaten by marine life. Even the noise generated by shipping and industrial activity can be harmful to bigger species such as whales, which are also killed by ship propellers.

The world must act to save the oceans from these perils through the Convention on Biological Diversity (CBD) and Marine Protected Areas (MPA). The CBD has established a target of 10 percent of all coastal and marine waters being protected in reserves by 2020. Moreover, as part of its Jakarta Mandate on marine and coastal biodiversity, the CBD is committed to the establishment of and implementation of a global program of making fisheries and mariculture sustainable, blocking the pathways of invasions of alien species and increasing ecosystem resilience to climate change.

This does not mean that we should not harness the ocean’s resources in areas other than MPAs. It means that we should do so sustainably. Fishing apart, ocean organisms provide a host of other benefits. For example, many marine plants and animals contain a multitude of substances already being used in medicines.

A 2010 study predicted the existence of between 250,000 and close to 600,000 chemicals in the marine environment, 92 percent of which remained undiscovered; those chemicals, the study’s authors estimated, might yield up to 214 new anti-cancer drugs. Thus the seas give us life in more ways than one. The oceans belong to all. Even those living in a landlocked country, thousands of kilometres from the nearest coast, benefit from the ocean’s role of nurturing life. It is thus essential to protect and preserve our oceans while sustainably harnessing its potential for human advancement.