More Science in Brazil

Part 2. Living in Smoke

Forrest M. Mims III

Editor's Note: The author's research for NASA in Brazil's Amazon basin in 1995 was described in three previous columns (see Part 1, 2 and 3). This is the second installment of a series about expanded research in Brazil during 1997.

Last week's installment ended with Brad White and me on a night flight from Sao Paulo to Cuiaba in western Brazil.

Because of a mechanical delay in Atlanta, we had missed the only flight to Alta Floresta, our final destination. So we took a midnight taxi ride to a cheap hotel where I once stayed. It was among the few places our meager NASA budget could afford.

The next morning we boarded a small turboprop for the trip to Alta Floresta, a town so remote it doesn't appear on many maps.

As we flew north, the range land below gradually turned to forest. Enormous blocks had been burned to form immense cattle pastures.

Soon the smoke beneath the plane became so thick the that the ground was obscured. We were flying over a vast blanket of gray that extended to the horizon.

After half an hour or so watching this eerie scene, the pilot muttered a few fast words in Portuguese over the intercom. Suddenly there was a very loud bang. Immediately the plane began falling so rapidly that everything not strapped down by a seat belt flew to the ceiling. Everything in my shirt pocket took the same trip.

Just as quickly the little plane stopped falling. While passengers gathered their things, I looked out the window to see if the wing was still there.

Finally we descended through the gloomy blanket of gray and landed at a tiny town half way to Alta Floresta. Ten or more acres of trees adjacent to the runway were in flames. After refueling, we took off for Alta Floresta. The smoke was so thick when we arrived that I thought the pilot might have difficulty landing. Later we learned that the smoke could be much, much worse.

Alta Floresta was founded in a gold mining area 9 degrees below the Equator. Most of the gold has played out, and agriculture and logging are among the major businesses. Tourism is important to the nearly empty Floresta Amazonica Hotel on the outskirts of town, which is where Brad and I set up shop. The few visitors at the hotel can watch monkeys, toucans and colorful macaws within a few yards of their rooms.

Early our first morning we began what was to become a daily ritual. First, various recording instruments were set up to measure sunlight and temperature. Then we pointed four instruments called sun photometers at the sun to measure how much sunlight was blocked by the smoke. We also measured the ozone layer.

We had to use the sun photometers every 15 minutes, so there was little time for breakfast. There was no time for lunch since midday is when the most important measurements were made.

An important study of bacteria floating in the air was sandwiched between the many sun and sky measurements. Did the smoke block so much ultraviolet that more bacteria could survive in the air? To find out, every 90 minutes I placed an open tray of agar on a post for 20 minutes. While the tray was exposed, I used two instruments to measure the sun's ultraviolet radiation. I then sealed the tray and stashed it in our room so any bacteria that fell on the agar would grow into colonies large enough to count. The results of this daily experiment showed a high correlation (r2 = 0.83) of reduced ultraviolet and increased bacteria counts.

A thousand or more new fires were started each morning, so the smoke was usually thickest by late afternoon. By then the sun became a dim orange ball in the sky.

While every day was smoky, some days were incredibly so. One day the visibility was so poor the airport had to be closed. The hotel manager and some of her workers were made ill by the smoke.

Sunset was the highlight of each day. That's when Brad and I packed up the instruments and walked over to the hotel's restaurant for our only real meal of the day. We always ordered the hotel's delicious platter of rice and steak. For the first time we could relax, visit, and watch the big geckos stalking insects under the lights on the wall.

Our steak had been raised on grass where rain forest once stood. The problem is that the ground is more laterite gravel than soil. Often the grass only grows for a few years before the pastures are abandoned.

After supper our flashlight beams formed yellow cones in the smoke, which dimmed the moon and made it orange. The smoke blocked the stars, but sometimes an orange Jupiter could be seen.

Supper never lasted long enough, for each night there were chores to do. Water had to be pumped by hand through a filter into our water bottles. Clothes had to be washed in the sink in our room.

Each night after the housekeeping chores were done, I stayed up to midnight counting and photographing the bacteria colonies that had grown from bacteria that fell on the trays two days before.

After a few weeks of this routine, Brad and I could hardly wait for the field trip we had planned. Soon we would leave remote Alta Floresta for the even more remote Cristalino River.

We could take only some clothing and our backpacks, which we stuffed with instruments and water bottles. We must have seemed a pretty odd pair, as we set off for the Cristalino River and the adventures that awaited us there.

Forrest M. Mims III and his science are featured online at www.forrestmims.org.

, Seguin, Texas. The column is written for a general audience.