Dear Ecologgers, Recent discussions on humans and the environment, agricultural practices, the "green revolution", and food security have been interesting to follow. But I feel the "invisible elephant" has been neglected in these dialogs.
Biocides are a huge and neglected topic. Pesticides, Herbicides, fungicides, and the list goes on..... These are the terms that have been used to mislead the public and scientific community. They are all biocides that work by disrupting core metabolic processes of the target organism. Those responsible for developing biocide formulations exhibit complete and utter disregard for evolutionary history. As the effects of biocides on non-target organisms are largely predictable from phylogenetic relationships to target organisms, because of the common evolutionary origin of the metabolic machinery by which biocides have mode of action. I explicitly mean, microbes to multicellular organisms (i.e. humans). Xenobiotic metabolism refers to the pathways that are employed in the detoxification of harmful chemical and waste products that enter a body or are produced by a body. Xenobiotic metabolic pathways are largely conserved from microbes to multicelluar organisms (with many innovations along the way). It is by xenobiotic metabolism that insects, weeds, and other "pest" develop metabolic resistance to biocides. In fact, there are more cases of evolved resistance to biocides than there are biocide formulations....we are loosing the biochemical arms-race. One prime example is glyophosphate-resistant crops (i.e. Round-up ready) which account for >80% of the 134 million hectares of transgenic crops grown each year in at least 25 countries (see Green and Owen 2010 "Herbicide-resistant crops:...") This vast application of a single herbicide has been the cause of strong selection on wild populations of weeds and other non-target plants, and that strong selection has yielded an increasing number of herbicide-resistant plants. Herbicide resistant plants that jeopardize food security. While the biocide arms-race is loosing ground to the evolution of resistance in "pest", tons of biocides are being applied. Many of the biocides that we have banned in the US are now exported from the US to the tropics and other developing nations. In the tropics growing seasons are longer, there are more "pest", and more biodiversity that is imperiled from changes in land use. More biocides are applied in the tropics than higher latitudes. >From South American farmers, we know that pesticides/herbicides not only affect insects/plants but cause humans cancer caused by the disruption of metabolism (i.e. humans with high exposure or less tolerance are being selected against). From Europe, we know that streams affected by pesticides exhibit reduced biodiversity (see SPEAR pesticides). From coral reefs, we know that herbicides affect the coral's symbiotic algae, cause stress, mortality, and reduced settlement/survival. We know biocides are making it to the Great Barrier Reef, but less is known about the relatively more imperiled Caribbean Sea. Corals are the structure that facilitates the amazing diversity of life on reefs (i.e. rain-forest of the sea). Loss of biodiversity translates to losses in ecosystem function. We know very little about the ecological effects of biocides, but we do know they have been applied by the ton since the 1970's. Since then, there has been >90% reduction of corals around the world, unknowable loss in biodiversity in Amazon and South America, near loss of Bald Eagles and many other animals due to DDT, an increase in human developmental problems, cancer epidemics,....the list goes on and on. Of course there are many confounding factors here, but the one steadily increasing factor is biocide use. See "Cultivating Crisis" What do big biotech companies like Dow, Monsanto, etc. know about the casualties of their biochemical war on "pest"? Have they funded research to look into the effects on whole ecosystems? Or just toxicology studies with little chance of detecting anything other than a lethal effect on a single organism (genomic approaches are sorely need in toxicology). I'm shocked by the particular lack of data regarding the marine realm. All rivers [of biocides] flow to the sea. "Chemicals are the language of the sea" and the vocabulary of that language has rapidly been broadened since the industrial revolution and exponentially broadened since the green revolution. Biocides have a huge potential to disrupt marine ecosystems through trophic cascades. Humans receive over 50% of the oxygen they breath and the majority of protein in their diets from the sea. Approximate 70% of the human race lives by the sea, and the prosperity of all humankind depend on the oceans. Since WW II, humans have used their arms-race innovations (radar, diesel motors, chemicals, etc.) to drive many fisheries species to commercial extinction. The hope is if we regulate fisheries more heavily, stocks may recover. Biocides may not prevent recovery, but should limit the rate of recovery. Technological innovations have fueled human population growth and made for a better quality of life. But at what cost? While acute affects of biocide exposure may seem limited, what do we know about the cost of nearly three decades of biocide use and build-up? While the "green revolution" and other technologies have fueled the fastest stint in human population growth in the history of the world, the green revolution's toxic biocides may be cause for the sharpest population decline in human history. Hopefully, the evolution of biocide resistance by wild populations will save us all. This optimistic hope will most likely be crushed globally by the continued "innovation", production, and application of biocides. Biocides are another grand experiment here on Petri dish Earth. It's too bad the "scientists" at billion dollar biotech companies are the PI's. If you think Big Biotech will save and protect us, consider the outcomes of other grand experiments like Big Oil's deep water drilling experiment, Big Tobacco smoking is healthy experiment, Big Auto's bigger cars are better experiment, and all the other exploits of "Big" Industries. Concerned M.S. Student, Jonathan Craft