Chapter 10: Freshwater Biomes

Written and Published by J. Mazza, K. Rippy, J. Tyburski, J. Camerota, and M. Gioiosi

10.1 Aquatic Biomes10.2 Standing-Water Biomes10.3Flowing-Water Ecosystems

10.1 Aquatic Biomes● Two important factors for aquatic biomes are; The amount of dissolved

salts and and the depth of the water.● Aquatic biomes can be divided into two groups: Freshwater and Saltwater.● An aquatic biome is one where organisms live in or around water.

PPT=Parts Per Thousand

Salinity

● Salinity is the amount of dissolved salts in a sample of water.

● Salinity of the Ocean is 30ppt; Freshwater 0.5ppt● It is measured in parts per thousand● Brackish water- more saline than fresh water, but less

than ocean water.

What is a freshwater biome?● made up of any body of water that is made of freshwater (lakes, ponds,

streams, and rivers.) They cover roughly 20% of the Earth● Must have a salinity of less than 1%● Exceptions= Great Salt Lake in Utah and Mono Lake in California. They

are Hypersaline lakes.

10.1 Water Depth● Amount of sun that reaches the bottom determines what kinds of

plants will form the bottom of the food web.

● From top to bottom the zones are as follows: Top(Photic) Zone, Middle (Aphotic)Zone, Bottom (Benthic) Zone.

Aphotic from the Greek a-,”without,” and phos, “light”

Water Depth● Benthic zone is the zone that is most affected and has the most

biodiversity depending on the depth and amount of sunlight. The floor of the body of water

● The usual Photic zone depth is about 100 meters deep.The top layer of water where photosynthesis can occur

10.2 Standing-Water EcosystemsFreshwater Biomes can be

divided into two different types:

Standing Water Ecosystem: ex. Lakes and pondsFlowing Water Ecosystem: ex. Wetlands such as bogs,

prairie potholes, swamps, and freshwater marshes

Freshwater Angel Fish (wikipedia.org)

Standing Water OrganismsThe top level of standing water

ecosystems supports the plankton community.

Plankton is a general term for microorganisms that are the size of dust particles.

Two main types of plankton:Phytoplankton-plankton that carry

out photosynthesis. Zooplankton-plankton that does

not carry out photosynthesis

Wetlands

Wetlands - ecosystem in which the roots of plants are submerged under water at least part of the year. ex. Marshes, Swamps, Bogs

Wetlands tends to be standing water.

Wetlands act as filters.

Wetlands Cont.Wetlands are being destroyed all over because of human activity. The Swamp Lands Act passed by congress in 1849 encourages people to fill and drain wetlands.

The Florida Everglades The history of the Florida Everglades shows how difficult it is to maintain a Wetland.

Once 160 km of swamp. To create farmland, water from Lake

Okeechobee was channeled. This created a maze of canals.

To save the wetland, Everglades National Park Was established in 1947. Because of human impacts, many animals were driven from their homes and humans ended up hurting them. In 1983, “Save our Everglades” campaign created 100,000 acres of restored wetland.

10.3 Flowing-Water Ecosystems

All aboveground bodies of flowing fresh water are called streams. Fresh water can also flow underground through aquifers. In some cases aquifers provide a habitat for organisms.

Stream Organisms

●Organisms that live in flowing-water habitats are adapted to the rate of the waters movement.

● Some organisms have hooks that enable them to grab a hold of plants, others have suckers that anchor them to rocks. Ex. insects and other fish

Streamflow● Most streams begin at a high altitude and gravity causes them to flow

downhill and usually towards the ocean. This is because inland areas usually have higher altitudes than coastal areas.

● The place where the stream begins is the source, or head, of the stream. Water near that source is called the headwater. Headwaters that are present in mountains are often cold and contain large amounts of dissolved oxygen that can support a variety of organisms. These headwaters tend to flow too rapidly for most organisms to live in them.

Streamflow● As the flow of the water slows, small particles of sand and organic

material(or sediments) that were carried by the flowing water begins to settle. The sediments that accumulate provide a place for plant roots to grow.

● The processes of sedimentation and erosion cause the course of the stream to change naturally over time.

● Human activities have a dramatic effect in changing the flow of streams. Change in the flow can cause damages or even destroy the habitats of other organisms.