The expression Photosynthetically Active Radiation, often abbreviated PAR, designates the spectral range of solar light from 400 to 700 nanometers that is useful to terrestrial plants in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be damaging to cells and tissues; fortunately they are mostly filtered out by the ozone layer in the stratosphere. Photons at longer wavelengths do not carry enough energy to allow photosynthesis to take place, and plants have developed, through billions of years of evolution, the capacity to scatter these photons away, hence the very high reflectance and transmittance of live green leaves.
Saturday, January 3, 2009
Monday, December 29, 2008
AGROBLOGGER
The Agroblogger is a natural resource management pundit dedicated to promoting some of the fundamental principles of localism and sustainability, advocating for the adoption of organic agriculture, Open Source models, Free Software, Fair Trade, permaculture, and appropriate technology.
The Swamp School
The Swamp School provides discipline-focused education and training in environmental and wetlands management. At home or in the field, The Swamp School has a course designed expressly from the recognized environmental scientist and instructor, Marc Seelinger.
Their weekly podcast focuses on recent regulatory and legal developments in the wetland field. We will also discuss updates to assessment methodologies as well as notes from the field section.
Saturday, December 20, 2008
The Deep Ecology Platform
The eight-point Deep Ecology Platform at present provides the unifying principles of the deep ecology movement.
The Green Web
The Green Web is an independent environmental research group and network with a left biocentric perspective.
Left Biocentrism Primer
Left biocentrism is a left focus or theoretical tendency within the deep ecology movement, which is subversive of the existing industrial society. Left biocentrism accepts the view that the Earth belongs to no one.
Friday, December 19, 2008
The Daily Climate
Works to increase public understanding of climate disruption, including its scope and scale, potential solutions and the political processes that impede or advance them. Creates, publishes and distributes content of the highest possible quality and integrity, offering enterprise reporting on relevant topics alongside a unique daily aggregation of global journalism on climate science.