How do volcanic eruptions effect the biosphere?

Group #4

What is a volcano?

• A volcano is a rupture on the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

Types of volcanic eruptions

• Magmatic eruptions: the decompression of gas within magma.

• Phreatomagmatic eruptions: the compression of gas within magma.

• Phreatic eruptions: the superheating of steam via contact with magma.

The effects of a volcano are complex, so the biosphere is not the only realm involved.

• Volcano >> geosphere >> atmosphere >> hydrosphere >> biosphere

• Volcano >> geosphere >> hydrosphere >> biosphere 

• Volcano >> geosphere >> atmosphere >> biosphere >> geosphere 

• Volcano >> complex interactions

How do volcanoes affect plants?

• Plants are destroyed over a wide area, during an eruption. The good thing is that volcanic soil is very rich, so once everything cools off, plants can make a big comeback!

How quickly do plants begin to grow back?

• The answer is that it depends on how much rain falls in the particular area.

How do volcanoes affect animals?

• Livestock and other mammals have been killed by lava flows, pyroclastic flows, tephra falls, atmospheric effects, gases, and tsunami. They can also die from famine, forest fires, and earthquakes caused by or related to eruptions.

• The impact of eruptions on insects depends on the size of the eruption and the stage of growth of the insect.

Long-term effects of an eruption

• The long-term effects of an eruption on wildlife are usually quite small. Certainly both plants and animals returned to the utterly devastated areas within only a year or so of the eruption.

• There are various variations on the main theory. In general it is proposed that volcanic activity put so much ash and/or gas into the atmosphere that the earth’s temperature either got too hot for the dinosaurs or got too cold for the dinosaurs.

How Long do Volcanic Eruptions Last?

• It is much more difficult to predict the end of an eruption than to predict its beginning. The table gives the length of time that volcanoes erupt.

• Explosive eruptions end when sufficient decompression is attained to cause magma chamber collapse and restoration of the initial pressure conditions.