In the past, I promised not to have too many "end of the world" posts, but this one is just too intriguing.
After dealing with the heckling from some immature friends for having giardia, a parasite that is endemic to the area we live, I got frustrated and began to research why parasites exist. I remember scratching through the itchiest of southern summers wondering how mosquitoes fit into ecosystems. In the end, no matter how grotesque I view mosquitoes to be, they are required to feed birds, frogs, and fish. When I confronted giardia, I had trouble finding the role they and other parasites play in our ecosystems. As it turns out, some scientists devote their lives to the buggers.
From a traditional ecological perspective, parasites act as regulators of species population and as an indicator of ecosystem health. A new study from Ecological Parasitology at the University of California Santa Barbara (UCSB) suggests that parasites also "drive the flow of energy in ecosystems." The findings show that the sheer biomass (weight or volume of organisms in a unit area or habitat) of parasites far outweighs that of free-living organisms. That means little bugs invisible to our eyes encompass more energy in our ecosystem than the things we often enjoy- birds, frogs, and fishes. Even crazier is the power of these microscopic creatures. Add in the energy hosts use to repair the tissue destroyed by parasites to the weight of the parasites and the effect is alarming. To put this into context one scientists explains,
"... in an estuary there are more kilograms of trematode worms - parasites - than kilograms of birds. If you could see the trematodes with binoculars, you might not bother bird watching."In my case, I can say I spent months of time and energy to get rid of these suckers, but in the greater scheme of an ecosystem, these scientists urge that we cannot ignore the power of parasites. One friend expressed it best, "Eesh, I don't understand if that means parasites are important, but you gotta respect them." The scientists do report that understanding the abundance of parasites will guide future research on how to protect free-living organisms.
Another report from the same research institute touts the importance of parasites in the food web. The article explains that the "pyramid of life" food web that we learned in kindergarten no longer applies. With parasites, there is a second inverted pyramid. Animals at the top have the greatest vulnerability to parasites which pass through prey from the bottom to the top of the pyramid. The study found that on average, food webs contain more links between parasites and their hosts than predators and their prey. The most loving review of parasites comes from study coauthor Andrew Dobson of Princeton University,
"Parasites may well be the thread that holds the structure of ecological communities together."Let's all jump on the bandwagon and praise the energy suckers! Truthfully, I am slightly in awe of the bugs in my belly, but I still do not understand how I have a condition my body cannot rid of itself. Did native Vermonters deal with this type of indigestion through their lives or did these people have defenses against the endemic parasite? Is pollution making us more susceptible to parasites? I did find one article explaining that nutrient pollution (soil run-off) could be the cause of a surge in parasites that cause deformities in frogs. Perhaps water pollution and an increase and of parasites could explain IBS and humans' digestive issues. No matter what, you have to respect the buggers.
1) University of California - Santa Barbara. "Parasites Vastly Outweigh Predators In Estuaries: Could Have Significant Ecological Implications." ScienceDaily 24 July 2008. 9 March 2009 http://www.sciencedaily.com/releases/2008/07/080723140323.htm.
2) University of California - Santa Barbara. "Study Shows That Parasites Form The Thread Of Food Webs." ScienceDaily 13 July 2006. 9 March 2009 http://www.sciencedaily.com/releases/2006/07/060713081231.htm.
3) Nutrient Pollution Increases Parasite-Drive Frog Deformities