Every day the earth is bombarded by 10^22 J of solar light
GPP is often about ½ of GPP
Primary producers only about 1% efficient
Anything that is taken into the body faster than it breaks down / gets expelled will accumulate. Some things are never expelled. Bioaccumulation occurs within a trophic level. Environmental persistence (does not break down) helps substance accumulate. Persistant Organic Pollutants (POPs) – we lack the enzymes to break them down, as they are relatively new to the world. Metals cannot degrade (they are elements) Eagles have recovered after the ban of DDT usage. Common in aquatic food chains (direct absorption). Algae absorb mercury (Methyl Mercury), only excrete slowly.
PCBs were used commercially since 1929 as coolants and lubricants, banned in 1976 in USA Lake Trout were as high as 24 ppm in the 1970s Water in 1994 ranged from 0 – 0.36 parts per trillion (0.000000 36 ppm) Source: http://epa.gov/med/grosseile_site/LMMBP/LMMBP_PCB.pdf
Halocarbons are also about 14% of the greenhouse gas warming effect (radiative forcing) CFCs last 50+ years in atm Skin cancer, plant DNA damage Montreal Protocol : 190 nations in 1987 regulate these gases Ozone depletion has stabilized Expected to be at pre-1980 levels by 2075!
Ch 55 Ecosystems Jeff Jewett ACS June 2010 Ver 1