...heard, half-heard, in the stillness between two waves of the sea.

Patching together a world view, the editorial overview for Nature's 'special' on Earth observation refers to the 'long zoom' (a phrase coined by the American technology writer Steven Johnson) which has created a peculiarly contemporary way of seeing:

This is when a camera focused on, say, a human eye appears to hurtle pell-mell through the pupil to the nucleus of a cell — or pulls back from the orbit of the eye to an orbit round the planet.

In the world of the long zoom, says Nature:

the planetary scale has a particular significance. It links every image of the world to the great image of Earth that contains them all.

...The creation of [the] new ways of seeing the world [made possible by earth observation systems] would be a significant aesthetic achievement even if they had no commercial, scientific or strategic use. In fact they have all three — as well as an even greater environmental usefulness.

The 'special' explores perspectives from space, ground level, the future and the past (including, vitally, the Keeling Curve). In Whole Earth comes into focus, Stewart Brand argues that two vastly different but complementary projects could transform our understanding of Earth. The long-standing mystery of how microbes run the world is closer to being solved, thanks to metagenomics — the DNA sequencing of whole populations of microbial life, he says, and if a project to record fluctuations in the solar energy that reaches Earth [the Deep Space Climate Observatory (DSCOVR)] gets back on track, we could begin to predict, and even manipulate, ecological changes on the planetary scale.

In Observing the ocean from within, Quirin Schiermeier reports on the Array for Real-time Geostrophic Oceanography or Argo, which has 3,000 different sense organs spread across seas all around the globe.

Argo's mission is to measure chemical and physical properties including salinity and circulation. But studying, and appreciating, the full range of life and ecosystems in the oceans is an even bigger undertaking.

From the time of Pliny until the late nineteenth century...humans believed that there was no life in the deep. It took a historic expedition in the ship Challenger between 1872 and 1876 to prove Pliny wrong; its deep-sea dredges and trawls brought up living things from all depths that could be reached. Yet even in the twentieth century scientists continued to imagine that life at great depth was insubstantial, or somehow inconsequential.

So notes Tim Flannery in his review Where Wonders Await Us Reviewing Claire Nouvian's The Deep and Tony Koslow's The Silent Deep. Flannery quotes William Beebe on his 1930 Round Trip to Davey Jones's Locker:

"Since...the Phoenicians dared to sail the open sea, thousands upon thousands of human beings had reached the depths at which we were now suspended, and had passed on to lower levels. But all of these were dead, drowned victims of war, tempest, or other Acts of God."

What Beebe saw on that trip—and reported with such vividness—was a glowing world of creatures so astonishing that for decades many doubted his veracity. The clear sea stretched endlessly, and was so full of luminescence that it sparkled like the night sky. Cavalcades of black shrimps, transparent eels, and bizarre fish approached the descending sphere, and when Beebe used his spotlight to see them, great shadows and shifting patches of light hovered just out of view, leading him to postulate the existence of giants in the Bermudan depths. And below the bathysphere? There, said Beebe, lay a world that "looked like the black pit-mouth of hell itself."

What lies beyond? Mark Schrope quotes Ron Douglas, who studies deep-sea vision at City University in London, compares exploration by submersible to

taking a Land Rover and going out into the savannah in the middle of the night with the stereo on full blast, the lights on full, with a rotating siren and expecting to see normal lion behaviour.

P.S. 20 Dec: In New Scientist's year end review, Catherine Brahic summarises:

This year, our life-giver, the Blue Planet, revealed a host of details about herself. We learned where to find the clearest seas, the oldest piece of the Earth's crust, why it hums, and how many volcanoes sit on the ocean floor. We now know how the weather makes the days a tiny bit longer, while climate change will make them shorter. Oh, and Earth is smaller than we thought.