Aquatic Ecosystems

1. Aquatic Ecosystems Ms. Hubbuch Chapters 7, 11 The Howard School

2. Different types of Ecosystems • The type of organisms in an aquatic ecosystem are mainly determined by the water’s salinity, the amount of dissolved salts the water contains. • Freshwater include the sluggish waters of lakes and ponds and the moving waters of rivers and streams. • Marine ecosystems include the diverse coastal waters areas of marshes, swamps and coral reefs as well as the deep, vast oceans.

3. Characteristics of Aquatic Ecosystems • Factors such as temperature, sunlight, oxygen and nutrients determine which organisms live in which areas of the water. • Organisms are placed in three groups based on locations and their adaptations. • Plankton – organisms that cannot swim against currents so they are drifters. • Nekton – are free-swimming organisms such as fish, turtles and whales • Benthos – are bottom-dwelling organisms such as mussels, worms and barnacles

4. Freshwater Ecosystems • Lakes can form naturally where groundwater reaches the Earth’s surface or they can be manmade following the construction of a dam. • The littoral zone is near the shore and has abundant and diverse aquatic life. • The benthic zone is located in the bottom of a pond or lake and is inhabited by decomposers, insect larvae and clams.

5. Eutrophication • Eutrophication is an increase in the nutrients in an aquatic ecosystem. • To begin eutrophication, there’s a influx of nutrients into a lake. • Plants and algae grow at an exponential rate. • As plants die, bacteria decompose them using the majority of oxygen available. • Over time, the lake becomes green with little oxygen left for fish or other organisms.

6. Freshwater Wetlands • A wetland is an area that is covered with freshwater for at least part of a year. • Marshes contain non-woody plants such as cattails. • Swamps are dominated by woody plants such as trees and shrubs.

7. Freshwater Wetlands • Wetlands are an important part of the planet serving a range of functions: • Trap and filter sediments, nutrients and pollutants. • Reduce flooding. • Buffering shorelines against erosion • Provide spawning grounds and habitat for rare, threatened and endangered species. • Provide recreational areas.

8. Florida Everglades • The Florida Everglades are located in Southern Florida. • They used to comprise 8 million acres but now cover less than 2 million. • http://www.youtube.com/watch?v=E4k84KW07Sw

9. Rivers • Many rivers originate from snow melt or rainfall in the mountains. • At its headwaters, a river is usually cold and full of oxygen and runs swiftly through a shallow riverbed. • As it flows down a mountain it becomes, warmer, wider and slower containing more vegetation and less oxygen. • http://sportsmansparadiseonline.com/Wolf_River_Fish_Cam.html

10. Estuaries • An estuary is an area in which freshwater from a river mixes with salt water from the ocean. • As the two bodies of water meet, currents form and cause mineral-rich mud and dissolved nutrients to fall to the bottom. • Estuaries are very productive ecosystems because they constantly receive fresh nutrients from the river. • The surrounding land, such as the mainland or peninsula, protects estuaries from the harsh force of ocean waves.

11. Estuaries • Estuaries support a diverse amount of plant and animal life. Nutrients are abundant and there’s plenty of light for photosynthesis. • Horseshoe crabs annually lay eggs in shallow areas of estuaries and many migrating birds depend on these for foods.

12. Estuaries • Salt marshes form where rivers deposit their load of mineral-rich mud. • Mangrove swamps are dense growths of mangrove trees in tropical and subtropical zones. • Barrier islands run parallel to sandy shores.

13. Coral Reefs • Coral Reefs are limestone bridges built by tiny coral animals called coral polyps and the algae that live inside them. • Polyps secrete calcium carbonate which accumulates and supports thousands of species of plants and animals. • They are found in warm salt water where there is enough light for photosynthesis.

14. Coral Reefs • Coral reefs are fragile ecosystems. If the surrounding water is too hot or cold for too long, or if it is too muddy, polluted, or high in nutrients, the algae that live in the corals will leave or die. • As a result, the corals turn white, a condition called coral bleaching. • Because coral reefs grow slowly, a reef may not be able to repair itself when parts of it are stressed or destroyed.

15. Oceans • Oceans, like freshwater systems, are divided based on temperature, sunlight and oxygen. • Shallow ocean water provide a rich supply of nutrients washed from land for many ocean organisms. • The ocean surface is home for many ocean organisms including plankton, which are the primary producers. • Deep ocean waters do not receive sunlight and therefore support a limited amount of life.

16. Oceans

17. North and South Poles • The arctic ecosystems are marine ecosystems because nearly all food comes from the ocean and the seas. • The Arctic Ocean is rich in nutrients from the surrounding land masses. • It supports large populations of plankton which feed a rich diversity of fish in the open water and under the ice. • The fish are food for ocean birds, whales and seals.

18. Oceans • Although oceans are huge, they are steadily becoming more polluted. • Litter and runoff from land are the main source of coastal pollution. • Overfishing is a serious issue and many animals are accidentally killed in trawl nets.

19. The Water Cycle

20. Global Water Distribution • 71% of the Earth’s surface is covered with water with nearly 97% of the water being ocean.

21. Surface Water • Surface water is fresh water on Earth’s land surface. It is found in lakes, rivers, streams and wetlands. • As a streams and rivers flow across the land, they form a flowing network of water called a river system. • The area of land that is drained by a river is known as a watershed.

22. Groundwater • Water beneath the Earth’s surface in sediment and rock formations is called groundwater. • As water travels beneath the Earth’s surface, it eventually reaches a level where the rocks and soil are saturated with water known as the water table.

23. Aquifers • An underground formation that contains groundwater is called an aquifer. • The water table forms the upper boundary. • Aquifers are an important water source for many cities and for agriculture.

24. Porosity and Permeability • Although rocks may appear solid, many kinds contain small holes or pore spaces. • Porosity is the percentage of the total volume of a rock that has spaces. • Water in an aquifer is stored in the pore spaces and flows from one space to another. • The ability of rock or soil to allow water to flow through it is called permeability.

25. Recharge Zone • To recharge an aquifer, surface water must travel down through permeable layers of soil and rock. • An area of the Earth’s surface from which water percolates down and into an aquifer is called a recharge zone. • Recharge zones are environmentally sensitive areas because any pollution in a recharge zone can also enter an aquifer. • A hole that is dug or drilled to reach groundwater is called a well.

26. Global Water Use • Human use water in three ways: • Residential Use • Agricultural Use • Industrial Use Globally, most freshwater is used for agriculture. A very small portion is used for industry and residential use but these numbers vary across the world.

27. Residential Water Use • Typical residential water uses include bathing, cleaning and cooking. • For water to be safe to drink, or potable, it must be treated. • Water treatment removes pathogens and pollutants.

28. Industrial Water Use • 19% of the world’s water supply is used in industry. • Water is used to manufacture goods, to dispose of waste and to generate power.

29. Agricultural Water Use • 67% of water goes towards agriculture. • Plants require a lot of water to grow and as much as 80% of the water evaporates. • Irrigation is the practice of providing plants with water from sources other than direct precipitation.

30. Water Management Projects • To supply dry regions with water, all or part of a river can be diverted into canals that carry water across great distances. • A dam is a structure built across a river to control the flow and generate electricity. • When a river is dammed and artificial lake, or reservoir, is formed behind the dam.

31. Water Management Projects Three Gorges Dam

32. Water Conservation • As water sources become depleted, water becomes more expensive. • Water conservation is one way that we can help ensure that everyone will have enough water at a reasonable price. • Drip irrigation saves water on farms. • Many people and businesses use rain barrels to collect rainwater.

33. Solutions for the Future • Some coastal communities rely on the oceans to provide fresh water. Desalinization is the process of removing salt from salt water. • Some countries import water from areas where it is plentiful. • Many speculate in the future we may tow icebergs to drier areas.

34. Water Pollution • Water pollution is the introduction of chemical, physical or biological agents into water that degrade water quality and adversely affect the organisms depending on the water. • The two main causes of water pollution are industrialization and rapid human population growth.

35. Water Pollution • Point-Source Pollution is pollution discharged from a single source. • Nonpoint-source pollution comes from many different sources that are often difficult to identify.

36. Water Pollution • Wastewater is water that contains waster from homes or industry. • Most wastewater from homes contains biodegradable material that can be broken down by living organisms. • One of the products of treatment is sewage sludge, the solid material that remains after treatment. • Sludge can sometimes be toxic and difficult to dispose of.

37. Water Pollution

38. Thermal Pollution • Thermal pollution occurs when the temperature of a body of water increases or decreases. • Many industries use water in cooling systems. It is drawn from a body of water, used and released at a much warmer temperature. • Sometimes dams release large loads of cold water which can also be harmful. • The oxygen content of water is tied to temperature which greatly affects fish.

39. Groundwater Pollution • Pollution of the surface water in an area can affect the groundwater. • Pesticides, herbicides, fertilizers and petroleum products are common groundwater pollutants. • Groundwater pollution is incredibly difficult to remediate.

40. Ocean Pollution • Pollution is often dumped directly into the ocean from rivers and ships. • The Great Pacific Garbage Patch floats in the Pacific Ocean and is filled with tiny bits of plastic. • Oil is a significant pollutant in the ocean and comes from spills and nonpoint sources onshore.

41. Water Pollution and Ecosystems • Many chemicals destroy the environment immediately upon entering. • Sometimes pollutants persist and biomagnifyby building up at higher levels as they are transmitted up the food chain.

42. Clean Water Act • The Clean Water Act set a national goal of making all natural surface water fit for fishing and swimming by 11983 and banned pollutant discharge into surface water after 1985. • It also required metals to be removed from wastewater. • Although we have not met the lofty standards, our nation has improved the health of water significantly since it was enacted.

43. At the end of these chapters you should… • Understand the stratification of freshwater and marine aquatic ecosystems. • Know how water is distributed on the planet and used. • Know the various types of pollution and how it is legislated. • Be able to define all of the bold words in this presentation. • Have a good break!