Environmental Science and Engineering Introduction

Study Notes

Environmental science brings together fields like ecology, biology, zoology, oceanography, atmospheric science, soil science, geology, and chemistry to study how natural and man-made processes interact and affect the Earth's biomes.
Environmental engineering applies mathematics and science to utilize the properties of matter and sources of energy to solve environmental sanitation problems.

An ecosystem is a functional unit of nature where living organisms interact among themselves and with the surrounding physical environment.
Ecosystems vary greatly in size, from small ponds to large forests or seas.
The two basic categories of ecosystems are:
- Terrestrial (forest, grassland, desert)
- Aquatic (pond, lake, wetland, river, estuary)
There are four levels of ecological organization:
1. Population: all members of a species in a given location
2. Community: all interacting populations in a given area
3. Ecosystem: the living community and physical environment functioning together as an independent and relatively stable system
4. Biosphere: the portion of the Earth where life exists, comprising numerous complex ecosystems

Inorganic substances (C, N2, S, P, O2, CO2, H2O, etc.) involved in material cycles
Organic compounds (proteins, carbohydrates, lipids, nucleic acids) that link biotic and abiotic components
Climatic regime (temperature, humidity, sunlight, amount of water, etc.)
Producers (autotrophic organisms) that manufacture food from simple inorganic substances
Macro-consumers (phagotrophs or heterotrophic organisms) that eat or ingest other organisms or particulate organic matter
Micro-consumers (saprotrophs or osmotrophs) that break down complex compounds of dead organisms

Human activities affect the environment, and the carrying capacity of the environment is limited by available abiotic and biotic resources and the ability of ecosystems to recycle residue.

Autotrophs: can synthesize their own food from inorganic compounds and a usable energy source
Heterotrophs: cannot synthesize their own food and are dependent on other organisms for their food
Types of heterotrophs:
- Saprophytes: live on dead matter (decomposers)
- Herbivores: plant-eating animals
- Carnivores: meat-eating animals
- Omnivores: consume both plants and meat

Symbiosis: living together with another organism in close association
Types of symbiosis:
- Mutualism: both organisms benefit from the association
- Parasitism: the parasite benefits at the expense of the host
- Commensalism: one organism benefits and the other is unharmed

Food chain: the transfer of energy from green plants through a series of organisms with repeated stages of eating and being eaten
Food web: the flow of energy and materials in a natural community, with many interactions occurring along food chains

The cycles of elements (carbon, oxygen, nitrogen, sulfur, phosphorus) through the Earth's systems (atmosphere, hydrosphere, biosphere, and lithosphere)
These cycles are essential for life and are influenced by human activities.