Coral Reefs: The Rainforests of the Sea Are Dying — Can We Save Them?

Imagine a city beneath the sea — a sprawling, three-dimensional metropolis of intricate architecture, blazing with colour, teeming with life, every surface occupied by a different organism going about its own intricate life. This is what a healthy coral reef looks like. It is one of the most complex, diverse, and beautiful ecosystems on Earth, the product of millions of years of co-evolution between thousands of species. And it is dying before our eyes. 

Coral reefs cover less than 1% of the ocean floor, yet they are home to more than 25% of all marine species. Approximately 4,000 species of fish depend on coral reefs. They support over 1 million species of plants and animals in total. For comparison, tropical rainforests — widely recognized as the most biodiverse terrestrial ecosystems — cover about 6% of land but support only slightly more species than reefs cover from their much smaller area. Coral reefs are, hectare for hectare, the most biodiverse places on Earth. 

Corals are extraordinary organisms. Each coral 'head' is actually a colony of thousands of tiny animals called polyps, living in a calcium carbonate skeleton they secrete themselves. Inside each polyp live microscopic algae called zooxanthellae, which use photosynthesis to produce most of the coral's food. This partnership between animal and algae is one of the most important and ancient symbioses in nature — but it is also extremely fragile. 

When water temperatures rise even slightly above the coral's normal range — by as little as 1°C for an extended period — the coral becomes stressed and expels its zooxanthellae. Without its algal partners, the coral turns white (a process called bleaching) and begins to starve. If temperatures return to normal quickly, corals can recover. But if the heat stress persists, or if bleaching events happen too frequently for the coral to recover between them, the coral dies. 

Climate change is making bleaching events more frequent, more severe, and more widespread. The Great Barrier Reef — the world's largest coral reef system, stretching 2,300 kilometres along Australia's northeastern coast — has experienced five mass bleaching events since 1998, the last three in consecutive years. Each event kills corals that took decades or centuries to grow. The reef that exists today is measurably smaller and less diverse than the reef of fifty years ago, and scientists are openly discussing whether it can survive the coming decades. 

India's coral reefs face the same existential threats, plus several additional local ones. The coral reefs of the Gulf of Mannar, Lakshadweep, and the Andaman and Nicobar Islands are all showing signs of bleaching and degradation. Coastal pollution from urban sewage and agricultural runoff fuels algae growth that smothers corals. Destructive fishing practices — dynamite fishing, bottom trawling, the collection of ornamental fish using cyanide — cause direct physical damage. Unsustainable coastal tourism introduces anchor damage and pollution. And the coral mining that once destroyed large areas of reef in the Gulf of Mannar, though now banned, has left lasting scars. 

Can coral reefs be saved? The answer depends almost entirely on how quickly and decisively humanity acts to address climate change. Even the most ambitious reef restoration projects — coral gardening, coral transplantation, assisted evolution to develop heat-resistant coral strains — cannot outpace bleaching if global temperatures continue to rise. The single most important action for coral reef survival is reducing greenhouse gas emissions to net zero as rapidly as possible. 

But in parallel with climate action, protecting reefs from local stressors can buy them time and increase their resilience. Establishing well-enforced marine protected areas, eliminating destructive fishing practices, reducing coastal pollution, and managing tourism sustainably all help reefs cope better with climate stress. India must do more in all of these areas. The coral reefs off our coasts are a national treasure, a source of biodiversity, food security, tourism income, and coastal protection. Losing them would be an irreversible catastrophe.

Content Courtesy: Inspired by NOAA Coral Reef Watch reports

Plastic Pollution: The Ocean's Invisible Enemy

 

Every year, approximately 8 million tonnes of plastic waste enter our oceans. That is the equivalent of dumping one garbage truck of plastic into the sea every single minute. By 2050, if we do not act, there could be more plastic in our oceans than fish.

Plastic never truly disappears. It breaks down into smaller and smaller pieces called microplastics, which are now found in the deepest ocean trenches, the highest mountain snowfields, and even inside the human body. Scientists have detected microplastics in human blood, lungs, and breast milk.

Marine animals suffer terribly. Sea turtles mistake plastic bags for jellyfish. Seabirds feed plastic fragments to their chicks. Whales wash ashore with stomachs full of plastic bags and nets.

The solution starts with us. Refuse single-use plastics. Carry a cloth bag. Say no to plastic straws. Support brands that use sustainable packaging. And demand stronger government policies to hold manufacturers accountable.

The ocean is not a dumping ground. It is the cradle of all life on Earth. Let us protect it.

Content Courtesy: Inspired by UNEP and Ocean Conservancy reports

Bioaccumulation and Biomagnification

Heavy metals (mercury, lead, cadmium), pesticides and herbicides (such as DDT) and endocrine-disrupting chemicals (PCB’s and BPA’s) do not readily biodegrade. These are fat-soluble substances that are stored in organisms and are not quickly broken down by bacteria or other decomposers. Bioaccumulation is the process by which persistent pollutants accumulate in the fatty tissues of organisms. These pollutants are absorbed at a greater rate than they are released and therefore build up within the individual organism. Biomagnification is the process by which persistent pollutants increase in concentration up a food chain. So secondary and tertiary consumers have higher concentrations than producers and primary consumers.

This phenomena has been observed with DDT, causing the thinning of eggshells in raptors, such as the threatened Peregrine Falcon. Rachel Carson, a marine biologist and conservationist,  made the American public aware of the environmental problems caused by synthetic pesticides, such as DDT, in her famous book, “Silent Spring”. DDT is now prohibited in most developed countries.

Mercury has been shown to bioaccumulate in marine food webs, affecting higher order consumers, such as dolphins, sharks and swordfish. As such, Food Standards of Australia and New Zealand recommend that the intake of certain types of fish is limited.

Content Courtesy : vceenviroscience

Small Plastics Pose Big Problem

A decade or so ago, scientists first discovered that tiny pieces of plastic debris discarded by human civilization — some only a few thousandths of a millimeter in size — were finding their way into the oceans. But since then, it’s become increasingly apparent that microplastics, as the miniscule trash is called, represent a potentially huge threat to aquatic animals, according to an article in the July 11 edition of the journal Science.

The article, by marine scientists Kara Lavender Law of the Sea Education Association in Woods Hole, Mass. and Richard C. Thompson of the UK’s Plymouth University, notes that researchers increasingly are focusing upon the danger from microplastics, because their size makes it possible for a huge range of organisms — from large marine mammals, fish and birds to zooplankton — to ingest them. (Indeed, a 2012 study found that they pose a health threat to Baleen whales.)

Photos: Life on the Ocean Floor Garbage Patch

A report issued in June by the Global Ocean Commission estimated that 10 million tons of plastic is dumped into the oceans each year. Some of the plastic is discarded into waterways and then is carried into the ocean, but it’s also lost or discarded at sea by ships, the article notes.

Larger plastic items degrade to form microplastic, but some of the particles also are being put directly into the sea, because bits of cosmetic beads and clothing fibers are small enough to pass through wastewater treatment systems.

Once in the oceans, the particles are transported far and wide in a complex pattern that is difficult to predict. However, scientists have found very high concentrations in the subtropical gyres -- that is, areas where currents rotate rapidly — and in basins such as the Mediterranean.

Microplastics are themselves toxic, but they also soak up harmful chemicals that contaminate the ocean, such as DDT and PBDEs, so that they deliver a concentrated dose to the animals who ingest them. Marine scientists also worry that microplastics will end up in seafood-eating humans as well.

Video: How Much Trash is in the Ocean?

Microplastics are just one of the environmental woes afflicting the world’s oceans, and pushing them perilously close to ecological collapse, according to an article published last week in Foreign Policy, a political science journal.

Solving the problem is difficult because 65 percent of the oceans are outside the territorial waters of individual nations, and have become the equivalent of a chaotic, lawless “failed state” such as Somalia on land, the Foreign Policy article argued.

Content Courtesy: Discovery