Catastrophic Events Impact on Ecosystems

1. Catastrophic Events Impact on Ecosystems

2. Floods

3. Floods • Flooding happens during heavy rains, when rivers overflow, when ocean waves come onshore, when snow melts too fast or when dams or levees break. • Flooding may be only a few inches of water or it may cover a house to the rooftop.

4. Floods • Floods that happen very quickly are called flashfloods. • Flooding is the most common of all natural hazards. • It can happen in every U.S. state and territory.

5. Environmental Impact of Floods • Floods are important in maintaining ecosystem habitats and soil fertility. • Human attempts at managing flood prone areas disrupt the natural flood cycle.

6. Environmental Impact of Floods • Activities such as drainage of wetlands and land clearance for farming; upstream development that replaces natural vegetation with paved asphalt; and construction of channels, levees, reservoirs change the flood cycle and often result in increases runoff, destruction of riparian habitat, and increased water pollution

7. Effects of Floods • Floods destroy drainage systems causing raw sewage to spill out into bodies of water. • Buildings can be destroyed which can lead to many toxic materials such as paint, pesticide and gasoline being released into the rivers, lakes, bays, and ocean, killing marine life. • Floods cause significant amounts of erosion to coasts, leading to more frequent flooding if not repaired. • Floods positively impact the environment by spreading sediment containing nutrients to topsoil.

8. Effects of a Flood on the Ecosystem • Plants • On dry land, plant life can benefit from the sudden appearance of a large quantity of flood water. • Water stored underground will be replenished by the floodwater, while soil above ground will be able to soak up the water. • Plants will be able to receive water as a result. • The nutrients carried by the flood water can also revive deprived plants and aid in the germination of seeds.

9. Effects of a Flood on the Ecosystem • Plants Continued • Food water may prove a new lease on life for an area. • The soil is likely to be more fertile, leading to a suitable area in which to grow crops. • Flooding can kill woody and herbaceous plants.

10. How Flooding Affects Animal Breeding • The environment in are areas where floods have occurred are more suitable for the reproduction of species of birds and some other animals. • Fish can breed and give birth in the areas where flood water stays for an extended duration.

11. Animals • Flooding forces many wild animals from their natural habitats. • Domestic animals are also left without homes after floods. • Rats may be a problem during and after a flood. • The large amounts of pooled water lead to an increase in mosquito populations.

12. Effects of Floods on Water-Based Ecosystems • Coral reefs are particularly at risk from the runoff from floods. • This runoff contains sediment and products such as pesticides and fertilizers, and will carry these into the ocean ecosystem. • Habitats may be destroyed, and animal and plant life are is likely to suffer. • Sediment may obscure the sunlight which inhibits photosynthesis of marine plants.

13. Effects of Floods on Water-Based Ecosystems • There are some benefits of flooding on the ocean ecosystems • The sudden appearance of an overflow of water can wash away unneeded salt, alongside man-made products like chemical waste. • This helps the flora and fauna thrive. • The flood water can also sweep away junk and debris which may have accumulated by the side of rivers.

14. Hurricanes

15. What is a hurricane • An intense, rotating oceanic weather system that possesses maximum sustained winds exceeding 74 mph. • It forms and intensifies over tropical oceanic regions. • Hurricanes are generally smaller than storms in mid-latitudes. • At the ocean’s surface, the air spirals inward in a counterclockwise direction. • This cyclonic circulation becomes weaker with height, eventually turning into clockwise outflow near the top of the storm.

16. How Hurricanes Affect the Ecosystem

17. How Hurricanes Affect the Ecosystem • Aquatic Ecosystems • Sediment erosion and deposition often affect oyster beds and coral reefs. • Saltwater intrusion in freshwater lakes and streams causes massive fish kills and affects the lakeside habitat.

18. How Hurricanes Affect the Ecosystem • The hurricane floodwater often carries many toxic substances (Heavy metals, pesticides, ammonia, phosphate, untreated sewage) • These substance can cause degradation of water quality, phytoplankton blooms, a decrease in dissolved oxygen and harm to many organisms. • Hurricanes have minimal effect on oceanic ecosystems since the contaminants tend to be flushed out by tidal flows.

19. How Hurricanes Affect the Ecosystem • Terrestrial Ecosystems • Hurricanes wreak havoc on terrestrial ecosystems. • Strong winds, storm surge, flooding and tornadoes all have an impact. • Coastal wetlands and barrier islands take the brunt of the storm surge. • The storm surge causes sediment to erode and shift.

20. How Hurricanes Affect the Ecosystem • Many barrier islands end up shifted or eroded below sea level. • Mangrove forests are devastated by wind. These trees often become fuel for wildfires. • This forces birds to find other places to rest. • Saltwater intrusion from storm surge also changes the wetland ecosystems. • Sea grass beds are often destroyed. • These are critical to feeding and nesting for many animals

21. Tornadoes

22. Tornadoes • A tornado is a violent rotating column of air extending from a thunderstorm to the ground. • The most violent tornadoes can have winds up to 300 mph.

23. How Tornadoes Form • You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. • When the two air masses meet, they create instability in the atmosphere. • A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. • Rising air within the updraft tilts the rotating air from the horizontal to vertical. • An area of rotation, 2-6 miles wide, now extends through much of the storm. • Most strong and violent tornadoes from within this area of strong rotation.

24. Tornadoes Effect on Ecosystems • Vegetation is uprooted. • Trees can be pulled out of the ground and carried to another location. • Organisms that live in or near these uprooted trees need to relocate. • This can cause a loss of species of organisms could also affect the interaction between plants and animals.

25. Tornadoes Effect on Ecosystems • The loss of plants caused by a tornado can allow new species of plants to grow in the cleared area. • Plants that survive can grow more abundantly then other species. • This loss of vegetation could also lead to soil erosion.

27. DROUGHTExtended periods with no precipitation Impact: • Death of vegetation, and loss of crops and food. • Lack of Water, Water restrictions. • Decreased air quality due to lack of vegetation • Increased erosion due to lack of vegetation • Increased risk of fires due to lack of moisture

28. Fire – natural (lightning, man) Impact: • Destruction of vegetation and structures, loss of habitat • Increased potential for erosion due to lack of vegetation • Creates air pollution • Returns nutrients to soil • Allows for new growth

29. Sources • http://sciencepolicy.colorado.edu/socasp/weather1/myers.html • http://www.fema.gov/kids/floods.htm • http://sciencepolicy.colorado.edu/socasp/weather1/myers.html • http://www.ehow.com/list_7494478_effects-flood-ecosystem.html • http://www.uwex.edu/ces/ag/issues/effectsoffloodingonplants.html • http://www.bt.cdc.gov/disasters/floods/pdf/animals.pdf • http://www.ehow.com/list_7494478_effects-flood-ecosystem.html • http://www.ehow.com/how-does_5170460_do-hurricanes-affect-ecosystem_.html • http://www.comet.ucar.edu/nsflab/web/hurricane/311.htm • http://www.weatherwizkids.com/weather-tornado.htm • http://www.wisteme.com/question.view?targetAction=viewQuestionTab&id=7397