H20 Molecules organize themselves into elegant hexagonal crystals that take up about 9% more space than they did when sloshing around in a liquid state.-The World Without us by Weisman.
Most liquids when chilled contract by about 10 per cent. Water does too, but only down to a point. Once it is within whispering distance of freezing, it begins—perversely, beguilingly, extremely improbably—to expand. By the time it is solid, it is almost a tenth more voluminous than it was before.-A Short History by Bryson.
Of the 3 per cent of Earth’s water that is fresh, most exists as ice sheets. Only the tiniest amount—0.036 per cent—is found in lakes, rivers and reservoirs, and an even smaller part—just 0.001 per cent—exists in clouds or as vapour.-A Short History by Bryson.
Air at 104F can hold 470x as much water vapor as air at -104F.-The Weather Makers by Flannery.
In a healthy ocean, there are a million bacteria per milliliter.-The World Without us by Weisman.
The main agent of heat transfer on Earth is what is known as thermohaline circulation, which originates in slow, deep currents far below the surface—a process first detected by the scientist-adventurer Count von Rumford in 1797. What happens is that surface waters, as they get to the vicinity of Europe, grow dense and sink to great depths and begin a slow trip back to the southern hemisphere. When they reach Antarctica, they are caught up in the Antarctic Circumpolar Current, where they are driven onward into the Pacific. The process is very slow—it can take fifteen hundred years for water to travel from the North Atlantic to the mid-Pacific—but the volumes of heat and water they move are very considerable and the influence on the climate is enormous.-A Short History by Bryson.
In winter, water in the ocean acts like a heater, and in summer, it acts like an air conditioner, as the air passing over the water is either warmed up or cooled down.-Secret Wisdom of Nature by Wohlleben.
Warm air rises and cool air subsides, forming a complex system of air movements that produce surface winds: easterly winds in high latitudes and near the equator; westerly winds in middle latitudes. Winds push the surface water along and so generate the ocean currents. Ocean currents move warm water away from the equator and cold water away from the polar regions.
Current flows in circles, called gyres. Where they flow parallel to continental coasts they are called boundary currents. Eastern boundary currents carry cold water and western boundary currents carry warm water. Boundary currents chill or warm air that passes across them. The gyres turn because of the Coriolis Effect, which deflects moving air or water to the right in the northern hemisphere and to the left in the southern hemisphere. It is caused by the earth’s rotation and its strength increases with distance from the equator.
The height of a wave depends on the force of the wind and on fetch.
Wavelength: Distance between wave crests.
Wave Period: Time from one wave crest to next.
Wave speed= wavelength/wave period.
Wavedepth is about than half the wavelength.
When the depth of water is less than half the wavelength the bottom of the wave slows. This reduces the wavelength but does not alter the period, so the waves grow higher.
Corallite is the external calcium carbonate covering that is secreted by polyps- cylindrical shaped animals between 1-3mm wide. A juvenile polyp drifts into the ocean. When it is ready to mature, it anchors itself to a solid surface and at the other end it grows tentaticles with which it gathers food items that float past. The polyp lives inside its corallite skeleton and exchanges nutrients with its neighbors- zooxanthellae (single celled protozoa of algae and dinoflagellates). These corallites merge and grow into coral reefs.
Reefs grow best is clear, shallow water at a temperature between 23-25C. The total reef area is ~175million sqkm.
The organisms that make up the world's reefs and atolls are in fact two living things in one. The larger partner in this ecological merger is a pale, sea anemone- like creature known as a polyp. It gains its greenish, red, or purplish hue from a lodger- a type of algae known as zooxanthellae. Under normal circumstances the relationship is a happy symbiotic one: The Coral polyp provides a home and some nourishment to the algae, while the algae provides the polyp with food from photosynthesis. As the temperature of the sea water rises, however, the algae's ability to photosynthesize is impaired, and it costs the polyp more to maintain its partner than it gets in return. As in many a failing relationship, this unequal situation leads to a split, though precisely how the polyp ejects the algae (if it does not leave under its own volition) remains a mystery. If T remains high for a month or two, without their algae the polyps starve to death, leaving a skeletal reef that will eventually become overgrown with soft corals and green algae.-The Weather Makers by Flannery.
Like sea urchins and starfish and clams and oysters and barnacles, reef-building corals have mastered the alchemy of calcification. What sets them apart from other calcifiers is that instead of working solo, to produce a shell, say, or some calcitic plates, corals engage in vast communal building projects that stretch over generations.-The Sixth Extinction by Kolbert.
Corals like light but can’t survive long exposure to the air, they tend to grow as high as the water level at low tide and then spread out laterally.-The Sixth Extinction by Kolbert.
Corals grew fastest at an aragonite saturation state of five, slower at four, and still slower at three. At a level of two, they basically quit building. Prior to the industrial revolution, all of the world’s major reefs could be found in water with an aragonite saturation state between four and five. Today, there’s almost no place left on the planet where the saturation state is above four, and if current emissions trends continue, by 2060 there will be no regions left above 3.5. By 2100, none will remain above three. As saturation levels fall, the energy required for calcification will increase, and calcification rates will decline. Eventually, saturation levels may drop so low that corals quit calcifying altogether, but long before that point, they will be in trouble. This is because out in the real world, reefs are constantly being eaten away at by fish and sea urchins and burrowing worms. They are also being battered by waves and storms, like the one that created One Tree. Thus, just to hold their own, reefs must always be growing.-The Sixth Extinction by Kolbert.
Coral cover in the Great Barrier Reef has declined by fifty percent just in the last thirty years.-The Sixth Extinction by Kolbert.
Reef-building corals lead double lives. Each individual polyp is an animal and, at the same time, a host for microscopic plants known as zooxanthellae. The zooxanthellae produce carbohydrates, via photosynthesis, and the polyps harvest these carbohydrates, much as farmers harvest corn. Once water temperatures rise past a certain point—that temperature varies by location and also by species—the symbiotic relation between the corals and their tenants breaks down. The zooxanthellae begin to produce dangerous concentrations of oxygen radicals, and the polyps respond, desperately and often self-defeatingly, by expelling them. Without the zooxanthellae, which are the source of their fantastic colors, the corals appear to turn white—this is the phenomenon that’s become known as “coral bleaching.”-The Sixth Extinction by Kolbert.
Once a year, after a full moon at the start of the austral summer, they engage in what’s known as mass spawning—a kind.-The Sixth Extinction by Kolbert.
Rivers carry minerals to the sea and these minerals combine with ions in the ocean water to form salts.-A Short History by Bryson.
Lake with Largest Surface Area: Lake Superior, USA- 82,414 sqkm (31,820 sqmi).
Lake with Largest Volume: Lake Baikal, Siberia- 23,600km3 (5663 mi3).
On low-lying ground besides rivers and river estuaries, in deltas, and along some coastlines, there are areas of land that are waterlogged or covered by shallow water, either permanently or for part of the year.
Includes: marshes, bogs, fens, peatlands, swamps, shallow lakes and ponds.
1971: The Ramsar Convention in Iran agrees to protect designated wetlands of international significance. By 2007, 154 governments had signed the Ramsar Convention protecting 1650 sites covering 149.6 million ha.
Ice Caps & Glaciers
A valley glacier is fed from above with ice, water, rock, and other debris. Geothermal heat warms the base of the glacier, causing it to flow by gravity. At the upper levels snow continues to accumulate in the net accumulation zone, but water is also lost be evaporation, sublimation and wind (deflation). In the net ablation zone below the equilibrium line the glacier loses mass faster than it receives it.
Ice Caps: Area less than 50,000km
Ice Sheet: Area greater than 50,000km2
During the La Nina phase, which until recently seemed to be the dominant part of the cycle, winds blow westwards across the Pacific, accumulating the warm surface water off the coast of Australia and the islands lying to its north. With the warm surface waters blow westward, the cold humboldt current is able to surface off the Pacific coast of South America, carrying with it nutrients that feed the most prolific fishery in the world, the anchoveta. The El Nino part of the cycle begins with a weakening of tropical winds, allowing the warm surface water to flow back eastward, overwhelming the Humboldt and releasing humidity into the atmosphere, which brings floods to the normally arid Peruvian deserts. Cooler water than upwells in the far western Pacific, and as it does not evaporate as readily as warm water, drought strikes Australia and SE Asia. When an El Nino is extreme enough, it can afflict two thirds of the globe with droughts, floods, and other extreme weather.-The Weather Makers by Flannery.