World's Oceans in 'Shocking' Decline
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Many people are not willing to admit that great changes are happening in the world, caused partly by the actions of humanity and partly by much greater forces. The true extent of world changes is not shown in the mass media, but soon the changes will be obvious to all with eyes to see and ears to hear. Messenger Spirit
YouTube Videos : Exploring Oceans: Overview - The ocean produces 70 percent of the Earth's oxygen and drives our weather and the chemistry of the planet. Most of the creatures on Earth live in the sea. But our knowledge of the ocean is far outstripped by our impact on it. National Geographic. Acid Test: The Global Challenge of Ocean Acidification - This groundbreaking NRDC (Natural Resources Defense Council) documentary explores the startling phenomenon of ocean acidification, which may soon challenge marine life on a scale not seen for tens of millions of years. The film, featuring Sigourney Weaver, originally aired on Discovery Planet Green. Uploaded by NationalGeographic on 16 Mar 2009
The ocean produces 70 percent of the Earth's oxygen and drives our weather and the chemistry of the planet. Most of the creatures on Earth live in the sea. But our knowledge of the ocean is far outstripped by our impact on it. World's Oceans in 'Shocking' Decline
By Richard Black, Environment correspondent, BBC News, 20 June 2011 The oceans are in a worse state than previously suspected, according to an expert panel of scientists. In a new report, they warn that ocean life is "at high risk of entering a phase of extinction of marine species unprecedented in human history". They conclude that issues such as over-fishing, pollution and climate change are acting together in ways that have not previously been recognised. The impacts, they say, are already affecting humanity. The panel was convened by the International Programme on the State of the Ocean (IPSO), and brought together experts from different disciplines, including coral reef ecologists, toxicologists, and fisheries scientists. Its report will be formally released later this week. "The findings are shocking." said Alex Rogers, IPSO's Scientific Director and Professor of Conservation Biology at Oxford University. "As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised. "We've sat in one forum and spoken to each other about what we're seeing, and we've ended up with a picture showing that almost right across the board we're seeing changes that are happening faster than we'd thought, or in ways that we didn't expect to see for hundreds of years." These "accelerated" changes include melting of Arctic sea ice and the Greenland and Antarctic ice sheets, sea level rise, and release of methane trapped in the sea bed. But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life. Some pollutants, for example, stick to the surfaces of tiny plastic particles that are now found in the ocean bed. This increases the amounts of these pollutants that are consumed by bottom-feeding fish. Plastic particles also assist the transport of algae from place to place, increasing the occurrence of toxic algal blooms - which are also caused by the influx of nutrient-rich pollution from agricultural land. In a wider sense, ocean acidification, warming, local pollution and overfishing are acting together to increase the threat to coral reefs - so much so that three-quarters of the world's reefs are at risk of severe decline. Carbon deposits Life on Earth has gone through five "mass extinction events" caused by events such as asteroid impacts; and it is often said that humanity's combined impact is causing a sixth such event. Some marine fish are already fished way beyond their limits - and may also be affected by other threats. The IPSO report concludes that it is too early to say definitively, but the trends are such that it is likely to happen, they say - and far faster than any of the previous five. "What we're seeing at the moment is unprecedented in the fossil record - the environmental changes are much more rapid." Professor Rogers told BBC News. "We've still got most of the world's biodiversity, but the actual rate of extinction is much higher [than in past events] - and what we face is certainly a globally significant extinction event." The report also notes that previous mass extinction events have been associated with trends being observed now - disturbances of the carbon cycle, and acidification and hypoxia (depletion of oxygen) of seawater. Levels of CO2 being absorbed by the oceans are already far greater than during the great extinction of marine species 55 million years ago (during the Paleocene-Eocene Thermal Maximum), it concludes. Blue planet The report's conclusions will be presented at UN headquarters in New York this week, when government delegates begin discussions on reforming governance of the oceans. In the long run, greenhouse gas emissions must be cut to conserve ocean life, the report concludes. IPSO's immediate recommendations include:
Carbon dioxide levels are now so high, it says, that ways of pulling the gas out of the atmosphere need to be researched urgently - but not using techniques such as iron fertilisation, that lead to more CO2 entering the oceans. "The challenges for the future of the ocean are vast; but, unlike previous generations, we know what now needs to happen." said Dan Laffoley, marine chair of the World Commission on Protected Areas and an adviser to the International Union for the Conservation of Nature (IUCN). "The time to protect the blue heart of our planet is now." http://www.bbc.co.uk/news/science-environment-13796479 The Five Great Extinctions The Cretaceous–Tertiary Extinction (the End Cretaceous or K-T extinction) 65.5 Mya (million years ago) Plankton, which lies at the bottom of the ocean food chain took a hard hit in an event that also saw the demise of the last of the non-avian dinosaurs. The giant mosasaurs and plesiosaurs also vacated the seas. An asteroid or volcano eruptions are thought to be to blame. The Triassic–Jurassic Extinction (End Triassic) – 205 Mya Having a profound affect on sea and land, this period saw 20 per cent of all marine families disappear. In total, half the species known to be living on Earth at that time went extinct. Gradual climate change, fluctuating sea-levels and volcanic eruptions are among the reasons cited for the disappearing species. The Permian–Triassic Extinction (End Permian) 251 Mya A period known as the "great dying" was the most severe of the earth's extinction events, when 96 per cent of marine species were lost, as well as almost three-quarters of terrestrial species. The planet took a long time to recover from what has also been called "the mother of all mass extinctions". The late Devonian Extinction 360–375 Mya Three-quarters of all species on Earth died out in a period that may have spanned several million years. The shallow seas were the worst affected and reefs would not recover for another 100 million years. Changes in sea level and climate change were among the suspected causes. The Ordovician–Silurian Extinction (End Ordovician or O-S) – 440–450 Mya The third largest extinction in Earth's history had two peak dying times. During the Ordovician, most life was in the sea, so it was sea creatures such as trilobites, brachiopods and graptolites that were drastically reduced. In all, some 85 per cent of sea species were wiped out. Waves of Destruction Case Study One in the panel's report assesses the "deadly trio" of factors – global warming, ocean acidification and anoxia (absence of oxygen). Most if not all of the five global mass extinctions in prehistory carry the fingerprints of these "carbon perturbations", the report says, and the "deadly trio" are present in the ocean today. Case Study Two looks at coral reefs, and the fact that these "rainforests of the sea" (so-called for their species richness) are now facing multiple threats. The panel concluded that these threats acting together (pollution, acidification, warming, overfishing) will have a greater impact than if they were occurring on their own, and so estimates of how coral reefs will respond to global warming will have to be revised. Case Study Three examines pollution, which is an old problem, but may be presenting new threats, as a wide range of novel chemicals is now being found in marine ecosystems, from pharmaceuticals to flame retardants, and some are known to be endocrine disrupters or can damage immune systems. Marine litter, especially, plastics, is a huge concern. Case Study Four looks at over-fishing: it focuses on the Chinese bahaba, a giant fish which was first described by scientists only in the 1930s, but is now critically endangered: it has gone from discovery to near-disappearance in less than 70 years. A recent study showed that 63 per cent of the assessed fish stocks worldwide are over-exploited or depleted. http://www.independent.co.uk/environment/nature/oceans-on-brink-of-catastrophe-2300272.html Acid Test: The Global Challenge of Ocean Acidification
This groundbreaking NRDC (Natural Resources Defense Council) documentary explores the startling phenomenon of ocean acidification, which may soon challenge marine life on a scale not seen for tens of millions of years. The film, featuring Sigourney Weaver, originally aired on Discovery Planet Green. |
