Catastrophic Events Impact on Ecosystems
Hurricanes
Hurricanes An intense, rotating oceanic weather system with sustained winds of at least 74 mph and a welldefined eye Conditions for formation: Warm water Light upper-level winds Pre-existing disturbance of thunderstorms Hurricanes produce damaging surface winds and storm surges
Hurricane videos http://www.youtube.com/watch?v=s76qn7bp CsQ http://www.youtube.com/watch?v=sxm5q1t GB6o&feature=pyv&ad=5241746182&kw=kat rina
How Hurricanes Affect the Ecosystem
Trees damaged, snapped, or uprooted Wind http://www.nhc.noaa.gov /aboutsshws.php
Storm Surge The storm surge causes sediment to erode and shift. Coastal wetlands and barrier islands take the brunt of the storm surge. Sediment erosion and deposition often affect Oyster beds Coral reefs Sea grass beds http://www.comet.ucar.edu/ns flab/web/hurricane/313.htm
Salt Water Invasion! Saltwater intrusion in lakes, streams, and wetlands change ecosystems (e.g. causes massive fish kills) The storm surge kills tree species that are not tolerant of salt water.
Flooding Moves Contaminants Contaminants (e.g. chemicals used to treat crops or solid and liquid wastes) are transported into groundwater Phytoplankton blooms lead to a decrease in dissolved oxygen
Floods
Floods Is an overflowing of water onto land that is normally dry Caused by intense or long term precipitation from thunderstorms, hurricane surges, or melting snow Most impact results from paving the ground and the precipitation becomes runoff Cause loss of life, disease, property damage or loss, contamination of water, and destruction of crops and livestock
Environmental Impact of Floods are important in maintaining ecosystem habitats and soil fertility Nutrients carried by floodwaters can benefit ecosystems and crops Expand habitats for fish, birds Recharge groundwater Floods
Environmental Impact of Floods Flood-management practices have affected floodplains and the nature of flooding Wetlands drained Land cleared for farming Upstream development that replaces natural vegetation with paved asphalt Construction of channels, levees, reservoirs
Effects of Floods
Animals Flooding forces many wild animals from their natural habitats. Domestic animals are also left without homes after floods. The large amounts of pooled water lead to an increase in mosquito populations.
The sudden appearance of an overflow of water can wash away Unneeded salt Runoff Flushes Away Contaminants like chemical waste Debris Contaminants
Tornadoes
Tornadoes A rotating column of air reaching from a thunderstorm to the ground. The most violent tornadoes can have winds up to 300 mph.
Tornado videos http://www.youtube.com/watch?v=vhkjv9gu ARQ http://www.youtube.com/watch?v=txsxki0w gxu
Volcanoes A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Volcanoes are formed when magma from within the Earth s upper mantle works its way to the surface. Eruptions occurring close to human settlements may spill and destroy lives and property.
Volcano video
Tornadoes Effect on Ecosystems Trees damaged, stripped, or uprooted Open forest canopies to sunlight Fallen trees offer shelter for small animals Potential destruction of waste storage or treatment facilities or chemical plants
Earthquakes Earthquake
Earthquakes Is the vibration of the Earth s surface that occurs after a release of energy in the crust This release of energy can be caused by a volcanic eruption, or movements of the crust
Earthquake videos
Tsunami
Tsunami Are large ocean waves produced by earthquakes, volcanic eruptions, or underwater landslides The waves can travel upstream in coastal estuaries and rivers Areas of risk are less than 25ft about sea level and within one mile of shore Impact includes drowning, flooding, contamination of water, fires from broken gas lines, etc.
Tsunami video
Wild fires A wildfire is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. Common causes of wildfires include lightning, human carelessness, arson, and volcano eruption. Wildfires can occur anywhere, but are common in the forested areas of the United States and Canada.
The Federal Government annually spends billions of dollars to suppress wildfires. Wildfires increase the potential for flooding, debris flows, and landslides. Smoke and other emissions contain pollutants that can cause significant health problems. Short-term effects: destruction of timber, forage, wildlife habitats, scenic vistas, and watersheds Long-term effects: reduced access to recreational areas; destruction of community infrastructure and cultural and economic resources Impact of Wild fires
Causes of Droughts Is an unusually long period of dry weather. Droughts are the result of many causes including, global weather patterns, high pressure, the tropical outlook and other global-scale variables. Severity depends upon moisture deficiency, duration, and size of area.
Impacts of droughts causes: water supply shortage crop failure livestock death increased forest fires.