Natural Cycles On a Global Scale
The Seasons
The most elemental of natural cycles is that of day and night and the seasons. Some astronomers assert that
about four and a half billion years ago the moon was detached into orbit of the earth after an astral body
struck the earth sufficient to cause the mass of the moon to separate from the earth. At the same time the
earth's axis received a tilt of 23.5 degrees and the earth assumed an annual wobble relative to its path
around the sun. The result of this was a blessing, in addition to supplying water for the oceans from the
asteroid belt of our galaxy. The variety of differing lengths of day and night were introduced and changed
over the seasons. Shorter days accompanied winter times when the axis of the earths rotation leans further
away from the sun in one hemisphere while the other hemisphere enjoys summers with longer daylight hours each
day as the axis spends more time leaning towards the sun in that hemisphere.
The moon exerts its own gravitational pull so that water of the oceans and larger water bodies is heaped
toward the moon as it circles the earth to produce high and low tides twice each day.
Wonderful effects arising from these variations affect all living things.
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Biologist Bernd Heinrich describes in his book, Summer World, how summer is the most intense time of
the year - " a time of green, urgency, and lots of love lost and found..." - billions of
animals awakening from dormancy, and billions more arriving from the tropics, engage in a wild orgy of courting,
mating, and rearing young. However, summer masks the underlying competition and struggle, wherein
every new life of any one species replaces, on average, equal numbers of deaths of that same species. And, for
each of the large animals there are necessarily also hundreds or thousands of deaths of smaller ones of other
species that get eaten to produce this life.
He gives a fascinating insight how the ending of summer occurs in the seasonal cycle, describing
how abscidic is produced by trees when lengths of nights indicate the time is nigh to drop their leaves, and
this molecule, abscisic acid, releases the leaves' hold on twigs and causes defoliation at summer's
end.
He relates that when nights become long enough, trees begin to shut down for the summer by forming a
corky layer of cells between leaf and twig. This layer, the abscission layer, then blocks off the transport
of material between the branch and the tree. Chlorophyll is then no longer replaced as it breaks down with
use; revealing the yellow and orange leaf pigments are revealed. The abscisic acid then does its job of
dissolving the corky cell layer that holds the leaves to the trees, and as the connection between leaf and
twig weakens, a breeze does the rest, and the leaf falls. However, the question is raised why many
members of these same tree families don't shed their leaves at the end of summer, while the others do. |
Clearly there are many wonders of nature that we simply do not understand. Leaves absorb carbon dioxide
from the atmosphere. The carbon is used to make wood of the tree and oxygen is released by the leaves as fresh
air for us to breathe. Water from the soil is absorbed through the roots to contribute to life sponsored by
the tree and some of it is transpired into the atmosphere. The how and why this is so is the wonder.
A multitude of other species of plants and trees cooperate to offer sustenance and shelter to animals. Each
in lockstep, having its own cycle of growth and decay while taking in energy and sustenance from the sun, the
earth's atmosphere and the water falling as rain, flowing from place to place on the earth's surface
and underground in aquifers' rocky systems.
All of life's systems are interdependent upon others and are rooted in the great natural cycles. There
is no single ecologic factor that acts alone in the environment. Moreover, environmental issues both impact
and are impacted by people.
Cycles
Water is the thread connecting all ecosystems on earth. To read how the Water Resources Atlas of Florida addresses these natural systems in Chapter 5 of that work, click the highlighted phrase.
the six cycles which are considered here on the following pages have significant effects upon Florida’s waters: The
Hydrologic Cycle, The Nitrogen Cycle, The
Phosphorus Cycle, The Carbon Cycle, El
Niño and La Niña, and Global Warming. Each of
these cycles is the result of natural and human influences occurring throughout the world over eons of time.
Natural Cycles
In the discussions of the natural cycles, when the Trade Winds, for example, are changed by phenomena such
as variations in ocean temperature or abnormally strong winds, El NiñoName given to the occasional development of warm ocean surface waters along the coast of Ecuador and Peru. When this warming occurs the tropical Pacific trade winds weaken and the usual upwelling of cold, nutrient rich deep ocean water off the coast of Ecuador and Peru is reduced. The El Niño normally occurs around Christmas and lasts usually for a few weeks to a few months. Sometimes an extremely warm event can develop that lasts for much longer time period or La Niña(Also sometimes called El Viejo) Is the opposite of El Niño. La Niña occurs when stronger than normal trade winds stir up cooler water from the ocean depths. weather effects
are caused. The description of the Hydrologic
or water cycle principles are the same even though the frequency or severity of storms may be changed by the
Niño/Niña cycles operating according to their own different periodic timing. The Nitrogen and
Phosphorous cycles are discussed as they give rise to the presence of nutrientsAny food, chemical element or compound an organism requires to live, grow, or reproduce.
which influence what grows in our water resources and can have a significant effect upon water qualityA term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose..
Global warming is a cycle over a long period of time and the Niño/Niña cycles may
progressively become affected by global warming.
Trade Winds
The name Trade Winds reflect the paths sailed by the sailing ships that carried goods, and the routes
chosen by them to catch the wind, and make better (more competitive) speeds from place to place.
For example, in general terms, air rises over the warmer parts of the earth in the Tropics and descends as
it cools and spreads at altitude from the equator northwards and south. The rotation of the earth imparts a
twist (or Coriolis EffectThe observed effect of the Coriolis force, especially the deflection of an object moving above the earth, rightward in the northern hemisphere and leftward in the southern hemisphere.) to change the
north and south components of the general direction of the air movement to give rise to the general effect we
refer to as the Trade Winds. At the surface, rising air gives rise to lower air pressures and descending air
to higher pressures. Thus at the surface of the earth, the trade winds are a pattern of winds
that are found in bands around the Earth's equatorial
region. The trade winds are the prevailing
winds in the tropics, blowing from the
high-pressure area in the horse
latitudes towards the low-pressure area around the equator.
The trade winds blow predominantly from the northeast in the northern
hemisphere and from the southeast in the southern
hemisphere.
In the zone between about 30° N. and 30° S., the surface air flows toward the equator and the flow
aloft is poleward. A low-pressure
area of calm, light variable winds near the equator is known to mariners as the doldrums.
Around 30° N. and S., the poleward flowing air begins to descend toward the surface in subtropical high-pressure
belts. The sinking air is relatively dry because its moisture has already been released near the Equator above
the tropical rain forests. Near the center of this high-pressure
zone of descending air, called the "Horse
latitudes", the winds at the surface are weak and variable. The name for this area is believed to
have been given by colonial sailors, who, becalmed sometimes at these latitudesThe angular distance north or south of the earth's equator, measured in degrees along a meridian, as on a map or globe. A region of the earth considered in relation to its distance from the equator: temperate latitudes.
while crossing the oceans with horses as cargo, were forced to throw some overboard to conserve water.
The surface air that flows from these subtropical high-pressure belts toward the Equator is deflected
toward the west in both hemispheres by the Coriolis
effect. Because winds are named for the direction from which the wind is blowing, these winds are called
the northeast trade winds in the Northern Hemisphere and the southeast trade winds in the Southern Hemisphere.
The trade winds meet at the doldrums. Surface winds known as " westerlies"
flow from the Horse Latitudes toward the poles. The "westerlies" meet "easterlies" from
the polar highs at about 50-60° N. and S.
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