Freshwater ecosystems Kinds Characteristics Threats.
-
Upload
howard-clark -
Category
Documents
-
view
231 -
download
0
Transcript of Freshwater ecosystems Kinds Characteristics Threats.
![Page 1: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/1.jpg)
Freshwater ecosystems
Kinds
Characteristics
Threats
![Page 2: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/2.jpg)
Aquatic ecosystems
Key distinction: salinity = salt content of the water
Measured in parts per thousand (ppt) 1 gm of salt in 1000 gms water = 1 ppt FRESH usually < 0.5 ppt OCEANS average 35 ppt 0.5 to 17 ppt is called BRACKISH
![Page 3: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/3.jpg)
Kinds of freshwater habitats
Rivers, streams– Flowing freshwater– Source: where it starts– Mouth: where it ends
Lakes, ponds
Wetlands
![Page 4: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/4.jpg)
All freshwater ecosystems
Just a fraction of the Earth’s water– .01% = one one-hundredth of one percent
Occupy less than 1 percent of the Earth’s surface
![Page 5: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/5.jpg)
Rivers and streamsMore than 3.5 million miles of rivers and streams
(including intermittent streams)
– Just the U.S.! More than 140 times around the Earth.
www.noaa.gov/str-plan/images/river.gif
![Page 6: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/6.jpg)
Rivers from start to finish
Source = Headwaters Can be:
– Snowmelt– Spring– Even a lake
Water is colder, clearer, more highly oxygenated
Organisms include trout, mayflies
Mouth: where the river ends
Usually the ocean or another river, or lake
River widens and slows, getting warmer, siltier.
Middle is most diverse, lots of plants
Near mouth, increased sediment limits light and plants, water is warmest
![Page 7: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/7.jpg)
What are some of the differences?
Trout stream, NW NJ Mississippi R. Greenville, MS
![Page 8: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/8.jpg)
Mouth
Mississippi River
delta
![Page 9: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/9.jpg)
Lakes and ponds
What’s the difference?– Ponds typically smaller– May be seasonal—that is, dry up part of the year– Lakes exist hundreds or thousands of years
But, even lakes can fill in or dry up
![Page 10: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/10.jpg)
![Page 11: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/11.jpg)
Parts of a lake
![Page 12: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/12.jpg)
Parts of a lake
Littoral zone: near shore– Nutrient rich, lots of plant and animal life– Warm
Limnetic zone: near surface, open water– Lots of light– Lots of plankton
Profundal zone: deeper, little light Benthic zone: the bottom, little light, low oxygen
![Page 13: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/13.jpg)
![Page 14: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/14.jpg)
Eutrophication
If nutrients increase too much in a lake, pond, or ocean, excessive plant growth results
Phosphorus Nitrogen NOT GOOD: why?
– As plants decay, decomposing bacteria use oxygen dissolved in the lake to do their jobs.
– Dissolved oxygen goes down
![Page 15: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/15.jpg)
Wetlands
CA OR AK
![Page 16: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/16.jpg)
Wetlands: what are they?
For regulatory purposes under the Clean Water Act, the term wetlands means "those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas."
![Page 17: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/17.jpg)
Wetlands
May be fresh or brackish Freshwater types include:
– Marsh– Swamp– Bog– Fen
![Page 18: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/18.jpg)
Marsh
Most common freshwater wetland in U.S.
Occur along streams or in depressions
Characterized by organic, wet soils and non-woody (i.e., no trees) vegetation.
![Page 19: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/19.jpg)
Swamp
Wetland dominated by woody plants
Common in SE U.S.
![Page 20: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/20.jpg)
New Jersey wetlands
About 916,000 acres, or 19% of New Jersey, is wetlands, which seems like a lot; but the bad news is that about 40% of the original 1,500,000 acres has been lost to dredging and filling, dams, farming, development and highways.
![Page 21: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/21.jpg)
1. NJ wetlands
![Page 22: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/22.jpg)
What good are wetlands?
Reduce flooding by acting like sponges
![Page 23: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/23.jpg)
![Page 24: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/24.jpg)
What good are wetlands?
Help clean water by acting like a filter– The plants and slow water flow in a wetland help
remove pollutants, leaving water cleaner downstream in a lake or river.
– Too much pollution can leave a wetland toxic to visiting animals, such as many birds.
![Page 25: Freshwater ecosystems Kinds Characteristics Threats.](https://reader033.fdocuments.net/reader033/viewer/2022042615/56649d8b5503460f94a72e85/html5/thumbnails/25.jpg)
What good are wetlands?
Protect shorelines from erosion
Erosion in this case came from grazing animals