Chapter 58

The Biosphere

Ecosystem effects on sun, wind and water

• Life on earth is influenced by the amount and variation of solar radiation and patterns of atmospheric and oceanic circulation

• Various seasons are a result of earth’s position to sun

• Elevation causes significant changes in temperature and moisture

• Curvature of paths of winds due to earth’s rotation – Coriolis effect

Earth’s Biomes

Earth’s Biomes

• Biomes are major ecosystems that include characteristic vegetational structures and their associated climactic conditions

• Biomes are defined by the factors like temperature and moisture, along with soil structure and mineral content which influence its primary production

• Eight principal biomes – tropical rain forest, savanna, desert, temperate grassland, temperate deciduous forest, temperate evergreen forest, taiga and tundra

Freshwater habitats

• Freshwater covers 2% of the earth’s surface

• Concentration of dissolved oxygen in water is major determinant of properties of freshwater communities.

• Oligotrophic lakes have high oxygen and low nutrients

• Eutrophic lakes are opposite to Oligotrophic lakes

Marine habitats

• Oceans cover 70% of earth’s surface

• Ocean is divided into several zones depending on depth, light penetration and proximity to land or bottom: intertidal, neritic, photic, benthic, and pelagic zones

• Phytoplankton is the major primary producer

• Estuaries occur where freshwater mixes with saltwater. Contain intertidal zones with salt marshes or mangrove swamps

Human Impacts on Biosphere: Pollution and Resource Depletion

• Freshwater environments are threatened by point-source pollution, diffuse pollution and acid precipitation

• Deforestation of terrestrial habitats leads to loss of habitat, disruption of water cycle, acid rain and loss of topsoil

• Marine habitats are being depleted of fish and other species by overfishing, destruction of coastal ecosystems and pollution

• Stratospheric ozone depletion has lead to an ‘ozone hole’ formation that is allowing more harmful UV-B radiation to reach earth’s surface

Human Impacts on Biosphere: Global Warming

• Global warming is caused by increases in atmospheric concentration of greenhouse gases, like Co2 (methane and nitrous oxide)

• Co2 allows solar radiation to pass through atmosphere but prevents long wave radiation from leaving the earth, and is increasing surface temperature

• Changing sea levels, increasing frequency of extreme climatic events, and expansion of tropical diseases

This project is funded by a grant awarded under the President’s Community Based Job Training Grant as implemented by the U.S. Department of Labor’s Employment and Training Administration (CB-15-162-06-60). NCC is an equal opportunity employer and does not discriminate on

the following basis: against any individual in the United States, on the basis of race, color, religion, sex, national origin, age disability, political affiliation or belief; and

against any beneficiary of programs financially assisted under Title I of the Workforce Investment Act of 1998 (WIA), on the basis of the beneficiary’s citizenship/status as a lawfully admitted immigrant authorized to work in the United States, or his or her participation in any WIA

Title I-financially assisted program or activity.

“This workforce solution was funded by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S.

Department of Labor’s Employment and Training Administration.  The solution was created by the grantee and does not necessarily reflect the official position

of the U.S. Department of Labor.  The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and

including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership.  This solution is copyrighted by the institution that created it.  Internal use by an

organization and/or personal use by an individual for non-commercial purposes is permissible.  All other uses require the prior authorization of the copyright

owner.”