1. Ecologists classify the major ecosystems of the world into biomes.
Biomes are large regions with distinct climates and certain species
adapted to them.
The Aquatic Biome is divided into the Freshwater and Marine Biomes
The Freshwater biome is defined as having a low salt concentration;
usually less than 1%. Plants and animals in freshwater regions are
adjusted to the low salt content and would not be able to survive in
areas of high salt concentration (i.e., ocean).
There are different types of freshwater regions:
ponds, lakes
streams, rivers
wetlands

2. There are different types of marine regions: oceans coral reefs
The Marine biomes cover about three-fourths of the Earth's surface and include oceans, coral reefs, and estuaries. Marine algae supply much of the world's oxygen supply and take in a huge amount of atmospheric carbon dioxide. The evaporation of the seawater provides rainwater for the land.
There are different types of marine regions:
oceans
coral reefs
estuaries

3. The Desert biome cover about one fifth of the Earth's surface and
occur where rainfall is less than 50 cm/year. Most deserts are
inhabited by highly specialized plants and animals. Soils often have
abundant nutrients because they need only water to become very
productive and have little or no organic matter. Disturbances are
common in the form of occasional fires or cold weather, and sudden,
infrequent, but intense rains that cause flooding.
There are different types of desert regions:
tropical
temperate desert
cold desert

4. The Forest biome occupies approximately one-third of Earth's land
area, account for over two-thirds of the leaf area of land plants, and
contain about 70% of carbon present in living things.
Forest biomes are dominated by trees and other woody vegetation
and can be classified according to latitude:
tropical rain forest
temperate deciduous forest
northern evergreen coniferous forest (boreal, tiaga)

5. The Grassland biomes are characterized as lands dominated by
grasses rather than large shrubs or trees.
There are three main divisions of grasslands.
tropical grassland (savanna)
temperate grassland
cold grassland (arctic tundra)
The Tundra biomes are the coldest of all the biomes. They are noted for their frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. Dead organic material functions as a nutrient pool. The two major nutrients are nitrogen and phosphorus. Nitrogen is created by biological fixation, and phosphorus is created by precipitation.
There are two main types of tundra:
arctic tundra
alpine tundra

6. Because we share the world with many other species of plants and animals, we must consider the consequences of our actions.
Over the past several decades, increasing human activity has rapidly destroyed or polluted many ecological habitats throughout the world.
Human impacts of aquatic ecosystems
Pharmaceutical waste= Excess drugs in the bloodstream make their way out of the body through urine and fecal matter, and the excreted chemicals flow with the sewage out of our homes.
Agricultural runoff= Runoff of farms and suburban areas can carry large quantities of
fecal matter and fertilizers.