Lecture 5

Topic: Global Ecology — the ecology of biosphere

Section objectives:

1. Vernadsky V.I. - the founder of study of biosphere

2. Concept of biosphere living-component and its biogeochemical functions.

3. Biogeochemical Cycles: Water cycle. Nitrogen cycle. Oxygen-Carbon cycle.

4. Terrestrial and Aquatic biomes.

1. Vernadsky V.I. - the founder of study of biosphere.

The term "biosphere" was coined by geologist Eduard Suess in 1875, which he defined as: The place on earth's surface where life dwells.

Some life scientists and earth scientists use biosphere in a more limited sense. For example, geochemists define the biosphere as being the total sum of living organisms (the "biomass" or "biota" as referred to by biologists and ecologists). In this sense, the biosphere is but one of four separate components of the geochemical model, the other three being lithosphere, hydrosphere, and atmosphere. The narrow meaning used by geochemists is one of the consequences of specialization in modern science. Some might prefer the word ecosphere, coined in the 1960s, as all encompassing of both biological and physical components of the planet.

The founder of the study about biosphere - is V.I. Vernadsky (1868-1945). Biosphere - is that area of the earth where life exists. Scientific work “Biosphere” (1926). The main idea of his study is a concept of ‘living matter”.

2. Biosphere components:

• Aerobiosphere (Atmosphere) - air

• Hydrobiosphere (Hydrosphere) - water

• Lithobiospere (Lithosphere) - earth's crust

• Noosphere - biosphere transformed by people activity and changed by scientific consciousness. The term “noosphere” was proposed by Le Rois (1927). From Greek: “noos” = “consciousness”.

A study of biosphere: study about the primary role of living organisms (living component) and their activity on the formation of earth's surrounding (Atmosphere, Hydrosphere Lithosphere).

Characteristics of biosphere:

1. The whole earth system

2. Self-regulation

3. Stability

4. Reproduction

Water when compare with air is the main limiting factor for life distribution. Life optimum is on the surface of surroundings division

The analysis of the average values for large squares shows that the productivity is between 200 and 20000 kcal/m² per year, and the total Earth productivity is about 10¹⁸ kcal per year.

Some theorists have postulated that the Earth is poorly suited to life, although nearly every part of the planet, from the polar ice caps to the Equator, supports life of some kind. Indeed, recent advances in microbiology have demonstrated that microbes live deep beneath the Earth's terrestrial surface, and that the total mass of microbial life in so-called "uninhabitable zones" may, in biomass, exceed all animal and plant life on the surface. The actual thickness of the biosphere on earth is hard to measure. Birds typically fly at altitudes of 650 to 2000 meters, and fish that live deep underwater can be found down to -8,372 meters in the Puerto Rico Trench.

For the last 100 years humankind has increased in numbers in 4 times, energy consumption – in 10 times, total product – in 17,6 times, mineral resources – in 29 times. 85% of all mineral resources that humans used throughout their history was extracted during XXth century. The total amount of used energy at the end of a century is only 3-4 orders of magnitude lower than solar energy entering the upper atmosphere. At present, ¼ of all land is occupied with agrocenosis and pastures and ¾ of the land not covered by ice turns out to be directly utilized. The world catch of fish has reached its theoretical limits. Changes in global climate of the Earth, intensifying the natural disasters, increasing damages and leading to extinction of many species, are clearly visible. The humans will double in size in XXIth century. Will biosphere withstand such load?

For the last 100 years humans in general have improved their life conditions. Scientific and technological advances have improved the work performance in many times and facilitated the lives of many millions of people. Mechanization, electrification, advances in chemical science and information breakthroughs became part of life of every human being in rich countries.

The World Community has started to help countries, that suffered from natural disasters – droughts, floods, earthquakes, fires. But even at ordinary periods, the World Community has provided significant food and medical help to poor countries. Such help decreased infant mortality and increased life expectancy in developing countries. Potent medications, aimed against inflammatory diseases (sulfamid medications, antibiotics) and a new vaccines aimed against infectious diseases were developed in the first half of this century. The natural spreading places of plague, malaria and other diseases, transferred by animals, were eliminated in many areas.