Monday, June 14, 2010
BUZZ OFF........................or maybe.....................BUZZ ON.
June 14/2010-11:04 AM EST.
By : Isaac N.
So, last night as I was drifting off to sleep, I started to think about the air quality warnings in the G.o.M., and the things I've read about physiological respiratory effects that are being encountered in the coastal areas. More importantly, ....how bugs breath, and what controls their widely varied multi-annual reproductive cycles. What's at the root of any type of population explosion ?
Let's look at the food chain as a pyramid.
In the grandstanding ways of evolution, when the organisms at the top of the food chain are displaced, the lower tier feeders move up to claim the vacant spots. Nature provides a way to recycle everything. Some very important things to think about currently are : the C02 levels in the coastal regions, the eventual mass kill-off of higher tier organisms on the food chain in the South-Eastern US states ( read my post on COREXIT and GM crops ), and the what's known as gas diffusion, which dictates the rate at which insects breath.
There are many different patterns of gas exchange demonstrated by different groups of insects. Gas exchange patterns in insects can range from continuous and diffusive ventilation, to discontinuous gas exchange. Discontinuous gas-exchange cycles (DGC), also called discontinuous ventilation or discontinuous ventilatory cycles, follow one of several patterns of arthropod gas exchange that have been documented primarily in insects; they occur when the insect is at rest. A rapid release of CO2 to the environment characterizes the open phase of discontinuous gas exchange cycles.
Insects typically maintain 4-5 kilopascals of oxygen in their respiratory systems, 4-5 times lower than the normal oxygen concentration in the atmosphere. In a normal oxygen-concentration environment, the insect breathes for a period of time and releases a burst of carbon dioxide. It then closes its respiratory system, blocking off more intake of oxygen, to maintain the internal oxygen concentration at 4-5 kilopascals, the right oxygen concentration for its body. In a low-oxygen environment, the insect opens its respiratory system for longer periods of time; when it closes the system, it does so for only a very short time. In a stream of air with high oxygen on the other hand, the respiratory system opens briefly and then closes firmly for a long time. In other words, insects are actively keeping oxygen out and doing it in a way that shows they know how to measure oxygen, their behavior indicates they are regulating oxygen.
The rate of gas diffusion is regarded as one of the main limiting factors (along with weight of the exoskeleton) that prevents real insects from growing as large as the ones we see in horror movies.
C02 is normally used by the human body, as well all other life on the planet. A small fraction is transported in red blood cells combined with the globin portion of hemoglobin as carbaminohaemoglobin. This is the chemical portion of the red blood cell that aids in the transport of oxygen and nutrients around the body, but, this time, it is carbon dioxide that is transported back to the lungs.
Carbon dioxide (CO2) is naturally present in the atmosphere at levels of approximately 0.035%. Short-term exposure to CO2 at levels below 2% (20,000 parts per million or ppm) has not been reported to cause harmful effects. Higher concentrations can affect respiratory function and cause excitation followed by depression of the central nervous system. High concentrations of CO2 can displace oxygen in the air, resulting in lower oxygen concentrations for breathing. Therefore, effects of oxygen deficiency may be combined with effects of CO2 toxicity.
It would seem logical then, that lower oxygen ppms and higher C02 ppms in the ambient air, would be conducive to rapid growth of insect populations due to the sped up respitory rates.
How insecst find diseased plants...
To find trees suitable for reproduction, insects track relevant environmental indicators, including chemical signals and, possibly, bio-acoustic ones emitted by stressed trees.
Higher plant surface temperatures, leaf yellowing, increased infrared reflectance, biochemical changes, and possibly stress-induced cavitation acoustic emissions, may all be positive signals to insects of host vulnerability.
Unfortunately, insects respond to changes in their thermal environment much faster than their hosts, either through migration, adaptation, or evolution. Under the stress of abrupt climate change the only short-term limit on their increasing populations may be their near total elimination of suitable hosts. In short, trees only adapt slowly to changing conditions, while insects can disperse widely and adapt much faster to abrupt environmental changes.
The assumption has been that the sounds are vibrations coming from individual cells collapsing, which is due to gradual dehydration and prolonged water stress. While cavitation produces some acoustic emissions in the audible range, most occur in the ultrasound range. In fact, counting ultrasonic acoustic emissions from cavitating xylem tissues is a widely accepted monitoring practice used by botanists to measure drought stress in trees.
The current signs of increasing insect populations at this early stage of warming does not portend well for forest health in the near future.
One conclusion appears certain. Extensive deforestation by insects will convert the essential carbon pool provided by the Earth’s forests into atmospheric carbon dioxide. Concomitantly, the generation of atmospheric oxygen by trees will decrease. Most immediately, though, as millions of trees die, they not only cease to participate in the global carbon cycle, but become potential fuel for more frequent and increasingly large-scale fire outbreaks. These fires will release further carbon dioxide into the atmosphere and do so more rapidly than the natural cycle of biomass decay. The interaction between these various components and the net effect is complicated at best—a theme that runs through links in the entire feedback loop.
So, in conclusion, don't be surprised to see explosions in the southeastern states this summer, as well as next spring, it will be compounded exponentially. Also, oxygen toxicity ,the primary cause of drain damage, has not been discussed.... it could be responsible for incompetent behavior in the Gulf situation.....no, seriously......I'll post an article later today, using air monitoring reports.