My understanding is that terrestrial vegetation is not a significant net oxygen source because the organic matter produced is all oxidized in a relatively short time. Most atmospheric oxygen is present due to burial of particulate organic matter, i.e. phytoplankton, in continental slope sediments, where it is taken out of the system. Please see also http://www.columbia.edu/cu/21stC/issue-2.1/broecker.htm Bob Miller
On 4/24/07, William Silvert <[EMAIL PROTECTED]> wrote: > > I think this is a common problem, not just for the Amazon. A nature > conservancy I have visited in a mangrove area claims that 95% of all > primary > production comes from mangrove swamps. It would help to have a reliable > source for the general questions of where regeneration of oxygen occurs, > where pharmaceuticals come from, and so on. > > Bill Silvert > > ----- Original Message ----- > From: "SUBSCRIBE ECOLOG-L Jacob Lowe" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Tuesday, April 24, 2007 4:16 PM > Subject: Amazon Rainforest "facts" > > > > Greetings everyone, > > > > As many of you know, I've spent the last year speaking at schools across > > Texas on work that Projects Abroad is doing in the Peruvian Amazon at > the > > Taricaya Research Center. During my presentations, I like to give a > quick > > "overview" of some of the encyclopedia-style "facts" about the Amazon, > > like > > biological diversity estimates, deforestation estimates, "tropical > > pharmacy > > to the world", etc at the beginning of the presentation. These > statements > > have included the following "facts" that I've retrieved from websites > like > > www.rain-tree.com, which does not cite any sources: > > > > 1. The Amazon Rainforest has been described as the "Lungs of our > Planet" > > because it provides the essential environmental world service of > > continuously recycling carbon dioxide into oxygen. More than 20 percent > of > > the world oxygen is produced in the Amazon Rainforest. > > > > 2. Currently, 121 prescription drugs currently sold worldwide come from > > plant-derived sources. And while 25% of Western pharmaceuticals are > > derived > > from rainforest ingredients, less than 1% of these tropical trees and > > plants > > have been tested by scientists. > > > > 3. The U.S. National Cancer Institute has identified 3000 plants that > are > > active against cancer cells. 70% of these plants are found in the > > rainforest. Twenty-five percent of the active ingredients in today's > > cancer-fighting drugs come from organisms found only in the rainforest. > > > > The more I read these claims, the more uncomfortably I am repeating them > > to > > students without any assurance of their accuracy. Can anyone here > > elaborate > > on some of these claims? For example, I've read where statement (1) is > a > > myth, and rainforest plants don't actually contribute any significant > net > > increase in atmospheric O2. For claim number (2), I'd like to know > > specifically which drugs come from the Amazon. Number (3) I'm having > > little > > luck from the U.S. Cancer Institutes's website. > > > > Most importantly, I'm having little luck getting sources from > > www.rain-tree.com. > -- Robert J. Miller, Ph.D. Postdoctoral Scholar Santa Barbara Coastal LTER Marine Science Institute University of California, Santa Barbara Santa Barbara CA 93106-6150 (805) 893-7295
