A little warmth goes a long way – the science of hot drinks | Life and style | The Guardian
The Atlantic Ocean is the second largest of the world's oceans, with an area of about .. Ocean currents influence climate by transporting warm and cold waters to . Ocean Agulhas Current meet to produce an intertidal zone on which shellfish, . hovered around 2 °C (36 °F) which made farming favorable at high latitudes. Cold currents bring cold water into warm water areas [from high latitudes to low latitudes]. Convergence: warm and cold currents meet. is descending, a condition least favorable for precipitation of any kind to take place. current edition: US edition . “When already cold,” says Bain, “it is unlikely that the hot drink will warm you Both drinks were beneficial, but the hot drink was much more beneficial.” that, he says, “are well documented in the literature to influence both the As a result, fake is in danger of overriding fact.
Since there are no continents in a band of open latitudes between South America and the tip of the Antarctic Peninsula, some of this water is drawn up from great depths. In many numerical models and observational syntheses, the Southern Ocean upwelling represents the primary means by which deep dense water is brought to the surface. In some regions of Antarctica, wind-driven upwelling near the coast pulls relatively warm Circumpolar deep water onto the continental shelf, where it can enhance ice shelf melt and influence ice sheet stability.
Some models of the ocean circulation suggest that broad-scale upwelling occurs in the tropics, as pressure driven flows converge water toward the low latitudes where it is diffusively warmed from above.
The required diffusion coefficients, however, appear to be larger than are observed in the real ocean.
Nonetheless, some diffusive upwelling does probably occur. Other sources[ edit ] Local and intermittent upwellings may occur when offshore islands, ridgesor seamounts cause a deflection of deep currents, providing a nutrient rich area in otherwise low productivity ocean areas.
Examples include upwellings around the Galapagos Islands and the Seychelles Islandswhich have major pelagic fisheries. The churning of a cyclone eventually draws up cooler water from lower layers of the ocean. This causes the cyclone to weaken.
Artificial upwelling is produced by devices that use ocean wave energy or ocean thermal energy conversion to pump water to the surface. Ocean wind turbines are also known to produce upwellings. In some areas, upwelling is a seasonal event leading to periodic bursts of productivity similar to spring blooms in coastal waters.
Wind-induced upwelling is generated by temperature differences between the warm, light air above the land and the cooler denser air over the sea. In temperate latitudesthe temperature contrast is greatly seasonably variable, creating periods of strong upwelling in the spring and summer, to weak or no upwelling in the winter. For example, off the coast of Oregon, there are four or five strong upwelling events separated by periods of little to no upwelling during the six-month season of upwelling.
In contrast, tropical latitudes have a more constant temperature contrast, creating constant upwelling throughout the year. The Peruvian upwelling, for instance, occurs throughout most of the year, resulting in one of the world's largest marine fisheries for sardines and anchovies. The Peruvian upwelling system is particularly vulnerable to ENSO events, and can cause extreme interannual variability in productivity. For example, a submarine ridge that extends out from the coast will produce more favorable upwelling conditions than neighboring regions.
Upwelling typically begins at such ridges and remains strongest at the ridge even after developing in other locations. While studying the trophic levels and patterns typical of upwelling regions, researchers have discovered that upwelling systems exhibit a wasp-waist richness pattern.
In this type of pattern, the high and low trophic levels are well-represented by high species diversity.
A little warmth goes a long way – the science of hot drinks
However, the intermediate trophic level is only represented by one or two species. This trophic layer, which consists of small, pelagic fish usually makes up about only three to four percent of the species diversity of all fish species present. The lower trophic layers are very well-represented with about species of copepodsspecies of gastropodsand species of crustaceans on average. At the apex and near-apex trophic levels, there are usually about species of marine mammals and about 50 species of marine birds.
The vital intermediate trophic species however are small pelagic fish that usually feed on phytoplankton. In most upwelling systems, these species are either anchovies or sardines, and usually only one is present, although two or three species may be present occasionally. These fish are an important food source for predators, such as large pelagic fish, marine mammals, and marine birds. Although they are not at the base of the trophic pyramid, they are the vital species that connect the entire marine ecosystem and keep the productivity of upwelling zones so high  Threats to upwelling ecosystems[ edit ] A major threat to both this crucial intermediate trophic level and the entire upwelling trophic ecosystem is the problem of commercial fishing.
Mid-Atlantic Ridge The MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other. While nine of these have collectively been nominated a World Heritage Site for their geological value, four of them are considered of "Outstanding Universal Value" based on their cultural and natural criteria: Continental shelves in the Atlantic are wide off Newfoundland, southern-most South America, and north-eastern Europe.
In the western Atlantic carbonate platforms dominate large areas, for example the Blake Plateau and Bermuda Rise. The Atlantic is surrounded by passive margins except at a few locations where active margins form deep trenches: There are numerous submarine canyons off north-eastern North America, western Europe, and north-western Africa. Warm currents flow parallel to the east coasts of the continents in tropical and subtropical latitudes.
This results in warm and rainy climates. These areas lie in the western margins of the subtropical anti-cyclones. Moderating effect They are responsible for moderate temperatures at coasts.
Canary cold current brings cooling effect to Spain, Portugal etc.
The mixing of warm and cold currents help to replenish the oxygen and favor the growth of planktons, the primary food for fish population.
The best fishing grounds of the world exist mainly in these mixing zones.
Drizzle Mixing of cold and warm ocean currents create foggy weather where precipitation occurs in the form of drizzle [Newfoundland]. Climate Warm and rainy climates in tropical and subtropical latitudes [Florida, Natal etc. Tropical cyclones They pile up warm waters in tropics and this warm water is the major force behind tropical cyclones. Ships usually follow routes which are aided by ocean currents and winds.
Atlantic Ocean - Wikipedia
If a ship wants to travel from Mexico to Philippines, it can use the route along the North Equatorial Drift which flows from east to west. When it wants to travel from Philippines to Mexico, it can follow the route along the doldrums when there is counter equatorial current [we will study this in next post] flowing from west to east.
Explain the factors responsible for the origin of ocean currents.Ocean Currents
The aridity of the hot deserts is mainly due to the effects of off-shore Trade Winds, hence they are also called Trade Wind Deserts. They include the biggest Sahara Desert 3. The next biggest desert is the Great Australian Desert. The hot deserts lie along the Horse Latitudes or the Sub-Tropical High Pressure Belts where the air is descending, a condition least favorable for precipitation of any kind to take place.
The rain-bearing Trade Winds blow off-shore and the Westerlies that are on-shore blow outside the desert limits. Whatever winds reach the deserts blow from cooler to warmer regions, and their relative humidity is lowered, making condensation almost impossible. There is scarcely any cloud in the continuous blue sky. The relative humidity is extremely low, decreasing from 60 per cent in coastal districts to less than 30 per cent in the desert interiors.
Under such conditions, every bit of moisture is evaporated and the deserts are thus regions of permanent drought. Precipitation is both scarce and most unreliable.