Oceans: Blue heart of the planet

Earth is a blue planet.

Almost three quarters of the earth’s surface is covered in water and around 90% of all the living space on Earth is contained in the oceans.

These vast reserves cradled early life and continue to be home to a wealth of extraordinary creatures. At least 230,000 unique species have been documented, although as humans have only explored a small fraction of the depths, there may be as many as two million.

As well as being home to everything from whelks to whale sharks, the oceans offer a range of critical services, including acting as a source of food and regulating the atmosphere.

In particular, the oceans are also vital as sponges for green house gases, taking carbon dioxide out of the atmosphere through two processes - dissolving straight into the water column and also through photosynthesis by phytoplankton.

Today, the oceans soak up around one third of all of human carbon emissions

But this comes at a terrible cost. The composition of the oceans is changing to become more acidic, threatening the tremendous diversity  of creatures that call them home.

In this film, veteran wildlife cameraman Doug Allan, sustainability advisor and author Tony Juniper, British Antarctic Survey scientist Dr Emily Shuckburgh and ecological economist Dr Trista Patterson reveal not only the huge diversity of life in the ocean but also the great contribution they make to cleaning our atmosphere.

From BBC Science-Environment

24 hour protection for rare Crane egg laid

A round the clock watch has been set up to protect a rare bird's egg.

It's the first Crane egg to be laid in the wild in  Slimbridge, South West England in more than 400 years.

Wildlife officers are worried that someone might try to steal the egg so are keeping close watch over the nest.

The nesting pair can be watched from hides at WWT Slimbridge

Cranes were hunted into extinction in the seventeenth century but have been reintroduced into Britain from other countries.

There are only about 20 pairs of the bird left in the UK so it is important that the egg is kept safe.

Workers at the nature reserve hope this could be the first of many eggs.

The cranes are large to very large birds, including the world's tallest flying bird. They range in size from the Demoiselle Crane, which measures 90 cm (35 in) in length, to the Sarus Crane, which can be up to 176 cm (69 in), although the heaviest is the Re-CrownedCrane, which can weigh 12 kg (26 lb) prior to migrating. They are long-legged and long-necked birds with streamlined bodies and large rounded wings. The males and females do not vary in external appearance, but on average males tend to be slightly larger than females.

The plumage of the cranes varies by habitat. Species inhabiting vast open wetlands tend to have more white in the plumage than do species that inhabit smaller wetlands or forested habitats, which tend to be more grey. These white species are also generally larger. The smaller size and colour of the forest species is thought to help them maintain a less conspicuous profile while nesting; two of these species (the Common and Sandhill Cranes) also daub their feathers with mud to further hide while nesting. Most species of crane have some areas of bare skin on the face, the only two exceptions are the Blue and Demoiselle Cranes. This skin is used in communication with other cranes, and can be expanded by contracting and relaxing muscles, and change the intensity of colour. Feathers on the head can be moved and erected in the Blue, Wattled and Demoiselle Cranes for signalling as well. Also important to communication is the position and length of the trachea. In the two crowned-cranes the trachea is shorter and only slightly impressed upon the bone of the sternum, whereas the trachea of the other species is longer and penetrates the sternum. In some species the entire sternum is fused to the bony plates of the trachea, and this helps amplify the crane's calls, allowing them to carry for several kilometres.

From CBBC/ BBC and Wipedia