The Jungle

I needed to sit and read a meter every 5 minutes or so, and was able to observed the stream more closely. While sitting on the stream bank, the diversity of types of tadpoles was unbelievable. I had been told how many species could be found in the sream, but the words did not convey the reality. Herpetology in general, and immature frogs in specific are not my areas of expertise, so I could not identify individual tadpole species. Actually, very few people can accurately identify most of the species in these streams from the tadpoles. In our group Edgardo and Scott were the specialists and the rest of us were just learning. Still, even to my unpracticed eye there was a clear variety present.

Some tadpoles were larger than my thumb and had very streamlined bodies. These used the suckers on their mouth to attach to rocks in faster waters. A large rock could have 10 or 20 of these. The scrape marks where these tadpoles had fed on the algae attached to the rock were apparent.

Chubby tadpoles with bodies that looked like slightly flattened spheres with a diameter wider than a quarter squiggled along the bottoms of the pools. These were not extremely fast and I caught one and its body felt like a bag of water. I released it and it skittered away. I wondered how such a slow large animal could exist without being preyed upon by snakes, lizards, and birds around the stream? Perhaps the fact that they were like a bag of water indicated that there was very little nutrition to be had in one of them, or maybe they were toxic. Given the impending extinctions, it is possible nobody will ever know the answer to the question.

Small tadpoles with bodies the sizes of orange seeds were wriggling around in shallow waters. I turned over some of the large wads of leaves on the stream bottom. Tadpoles with bright red blood vessels skittered away.

The open areas of the pool were perhaps 10 feet long, 10 feet wide and a half foot deep. Every one of these areas had herds of hundreds of small tadpoles, each the size of a pea, grazing on the microbes (algae, fungus, and bacteria) that lived attached to the sand and gravel. Any sudden movement would cause them to scatter for a while and hide, only to emerge a few minutes later and continue their incessant eating. Their only job in life was to gain enough energy to emerge from the stream, morph into an adult, mate, and produce more offspring.

Ecology is full of technical words, and the film of organism the tadpoles eat that is found on the bottom of the streams is called periphyton, a biofilm, or in more old fashioned terms, aufwuchs (one of my favorite words for some reason). In some strange way these tadpole flocks (there is no technical term for a group of them that I am aware of, maybe they school like fish) reminded me of the herds of bison that roam across the Kansas Prairie grazing the grass. Oh give me a home, where the tadpoles roam! Both the tadpoles and the bison are mainly eating machines and consume for most of their time. This constant eating is a requirement for any animal that eats relatively low quality food like grass or periphyton.

Time between writing down numbers offered me my first chance this trip to contemplate the riot of diversity that is a tropic rain forest. Evolution is occurring at breakneck speed relative to temperate systems. This has led to far more complex and diverse systems than occur in temperate habits. There are so many species of plants and animals that it is difficult to know how they interact, and fascinating to consider the linkages.

Plants struggle for light and nutrients. Water is not a problem here. Trees soar hundreds of feet upward into the canopy to intercept light. The trees have shallow roots that spread to intercept nutrients as soon as they reach the forest floor in the form of a fallen leaf, dissolved in a rain drop, or in animal excreta. The trunks of trees have wide buttresses (flared ribs spreading to the forest floor) to support their tall trunks. The buttresses give the jungle floor the feel of a green cathedral. The trunks and branches of all trees are covered with vines, mosses and other plants. Every square inch of available space is used.

The forest cuts the wind so flowers must be pollinated by birds, insects or bats. Each flower has its own tricks to lure the specific pollinator it needs and to exclude animals trying to steal the reward they offer to the type of pollinators they are trying to attract.

Exotic orchids offer odors as rewards that iridescent bees use to attract their mates. Each species of bee has its own cocktail of scents it harvests from different orchids, pollinating the flowers as they collect their scents. Humans were not the first species to discover the use of perfumes harvested from the surrounding to attract the opposite sex.

Some species of orchids are shaped to mimic bees. These flowers trick the male bees into attempted copulation, and deposit a pollen packet on to the presumably frustrated male. The bee goes on and if it makes the same mistake, it pollinates the next flower that fools it again (do they ever learn?).

This is not stark beauty like desert or tundra. It is diversity in your face with life evolved to use every nook and cranny. You cannot see far in the jungle, but there is lots to see right in front of you. There is something new for the observant biologist at every turn. If you sit still in one place in the jungle, the diversity will come to you. A mixed feeding flock of birds will eventually come foraging through the jungle. There are a half dozen species of birds in these flocks. Some eat bugs from the bottoms of leaves, others move up and down the trunks. Some of the species catch the insects that fly up when they are disturbed by the other birds. The birds receive benefits from feeding as a group; they are more likely to detect predators such as forest hawks, and their feeding habits complement each other.

Mixed feeding flocks are but one example of the co-evolution that is so common in the tropics. Species in this habitat are more likely than any other, with possible exception of coral reefs, to have evolved characteristic in response to the other species in the environment. Many species have complex adaptations to the others found in their environment.

The bull-horn acacia, Acacia cornigera, found on forest edges, is but one example. Ants protect trees and shrubs from grazers. If you hit the trunk of the shrub, the ants create a sharp smell which is the chemical (pheromone) that the ants use to signal each other that there is an invader. The ants swarm to attack any animal that tries to eat the tree. At night, the ants descend to clip back seedlings of other plants that might compete with the acacia. In return, the ants make their nest in large hollow thorns, and eat food bodies with fats and proteins, and nectar with carbohydrates produced by the plant. An acacia that has the ants removed is quickly consumed by the many herbivores found in the forest, including the ever-present leaf cutting ants. The ants and the acacias have evolved a tight cooperative (mutualistic) relationship in response to the benefits each can provide.

Many more examples of co-evolution exist. Toxic butterflies are brightly colored to advertise “don’t eat me”. Other species of butterflies have evolved color patterns that mimic the toxic butterflies so they are protected form predators. Every species of insect seems to have a specialized species of wasp that is parasitic upon it. This list of entangled interrelationships goes on and on and provides endless fascination for those interested in biology.

The First Experience with the Jungle Stream

After each of us had walked up and down the stream, the lead researchers met up and settled on the experimental reach. This was a 300-yard long stretch of stream surrounded by jungle with no major side channels and a variety of pools and shallow areas (riffles) characteristic of the stream. Most streams naturally sort themselves into a series of pools and riffles through the natural processes of erosion. These processes also lead to the typical meanders or “S” shaped bends that characterize flowing waters.

We picked out sampling sites from the top down, each one a bit farther apart from the next, so we could sample correctly. Once the experimental area was set, we worked with Edgardo and the other Panamanian helpers and found the best way to get from each sampling site along the stream to the next. They then used their machetes (a standard item of hiking and work equipment for most rural Panamanians) to clear a rough path. We marked each of the sampling sites along the stream with fluorescent tape, and set up our equipment for the initial measurements.

The trail had its hazards. We could not step in the stream while the experiment was going on, so needed to have minimal crossings and placed logs and rocks to get across where we did need to go. The trail wound its way through a bit of sparse jungle, but the animal trials made false leads and it was easy to wander off the wrong part and we had to pay careful attention. I hoped we would not be caught on the trail after dark. After the sparse jungle the trail went across a marsh, which we filled with logs, but they kept sinking as we would walk across them and the crossing was precarious at best. Right on the edge was a palm tree, and it was natural to grab the tree if you slipped into the mud off the logs. Unfortunately the tree had huge spines and the spines had an irritating substance on them. More than one of us grabbed the tree by mistake and was impaled. It is the kind of mistake you only make once; unfortunately I made that mistake several times.

The trail went next to the stream in parts and up and down steep-slippery sections, and included some logs. At the top of the trial was a large rock bar where we were setting up our system to add the chemicals to the stream. Just above this part there was a branch in the stream and the jungle was a bit more open, so large shafts of sunlight played through the branches onto the stream. This was a beautiful spot where we could see a slope too steep to climb rising between the two stream branches and huge trees towering hundreds of feet above our heads up the slope. Boulders the size of shuttle busses had fallen off the sides of the steep slope and lodged in the stream channel, and massive tree trunks had recently fallen across the stream above taking out many others on their way down. Above our top location, the stream was a jumbled mass, and it was very difficult to get through to the stream above, but the effect was wonderful.

Since we were going to use an inert chemical tracer to follow how nitrogen moved into the animals in the stream, samples needed to be collected to establish a baseline, and also to establish our basic protocols of measurement. Our group split into smaller groups.

One group collected the leaves and algae in the stream that form the base food source for all the animals in the stream. These samples were collected from a known area so we could estimate the relative amount of each that were present in the stream. At previous streams where the frogs had gone extinct the algae had exploded, so we wanted to catch that with detailed measurement. Even in these shaded streams there was enough light to allow some algae to grow.

Other groups collected the tadpoles, insect larvae, crabs, fishes and shrimps that populate the stream. These collections required careful netting and counting of individuals. We needed to be absolutely certain to quantify the existing conditions, because we knew of the changes that were coming and there was no going back. All these collections also needed to be made with much caution to minimize the disturbance of the stream channel so as not to interfere with our measurements in the following days.

Simultaneously, Bob, Alex, Matt and I set about making additional basic preliminary measurements required to start the experiments. Measurements were made with chemical sensors (measuring oxygen gas dissolved in the stream water, temperature, and other important water quality parameters). We started electrodes that would record the chemical conditions and temperature in the stream for the entire duration of the experiment. We took chemical samples required to calculate how to start the experiment the next day.

We started other measurements to determine how the stream responded to pulses of nitrogen and how pulses of tracers we released at the top moved down the stream. The results from these releases allowed us to account for how quickly the water moved through the system, and how much water was flowing. We took background samples of water to measure nitrogen so we could calculate how much nitrogen tracer to add and for how long. All these water samples would be analyzed later that same evening. Bob had a very nice approach where we could add the chemicals streamside and the samples would incubate and be ready to analyze that evening. Length, width and depth of every few feet of stream over the 300 yards or more of the experimental reach needed to be recorded.

Some time was spent just sitting on the stream bank and waiting between measurements, occasionally writing down numbers in the field book. Field research can be a curious mix of rapid, hard, physical work, then intense calculation and concentration, interspersed with waiting and observing.

Rio Maria and the jungle

Our research group had a central goal of finding out what would happen to the high elevation jungle streams after the tadpoles disappeared, so it was necessary to measure everything we could about the biology of the streams while the frogs and tadpoles were still there. Part of the process of scientific understanding is detailed observation, and we needed to be sharp and pick out the most important details to measure in this stream, to capture the true way the system worked. The baseline conditions of how the organisms influenced their environment, which organisms were there, and how they interacted all needed to be measured. We had limited time on this trip and had to make the best use of that time. This is the scientific way to talk about the environment we were about to enter, but there is more to biology than just measuring things.

It was hot in the sun out with the trucks as we fussed around with our gear. We got all the stuff we needed for our first set of measurements and started loaded up for our first trip into the jungle. The edges of the road were overgrown with a tangle of grass and bushes, as is always the case in the tropics; a road cut lets in valuable light and the plants fight for a toehold in this newly opened habitat. We needed to force our way through this on a tiny trail that had been hacked out by machete a few days before, and there were holes, fallen logs, and slippery muddy bits that needed to be negotiated with heavy loads of equipment. Our gum-boots did not making the footing easier, but they probably would protect from the fangs of a snake, and did keep our feet dry. Of course, we needed to also keep an eye out for sunning fer-de-lance, the extremely toxic snake that frequented the area.

As I entered the damp shade of the dense jungle near the stream, the temperature became more pleasant. This was another world. Rio Maria was a beautiful stream as it flowed through the jungle. A few shafts of sunlight found their way through the riot of tangled green to dance on the surface of the stream and dapple the rocks at the bottom of the clear waters.

Clear-winged butterflies flitted through the forest. These butterflies are fantastic as they have a rim of color around one or two almost completely clear wings. The oval-winged butterflies appear to fly slowly, but prior experience with a butterfly net convinced me that the clear wings make it difficult to see them and judge what direction they are going to fly. Or maybe I just suck at catching flying insects. Clear wings are probably a good predator defense, at least against inexperienced collectors.

Garish red flowers (hibiscus, passion flowers) dangled from overhanging vines or grew from the jungle floor. The vegetation is not extremely dense at the forest floor because so little light reaches it. Mosses covered most surfaces, including the tree trunks, fallen logs, older leaves, and the edges of the rocks near the streams. Tropical rainforest is part of what lured me back to Central America, and reality exceeded memory.
There were frog calls from hundreds of feet above in the tree canopy, down in the low vegetation, near the stream, and from the hillsides that surrounded us. The sound of chirping frogs constantly came from all directions. The calls blended with the insect sounds (cicadas and others) and bird calls.

Our first task was to decide which section of the stream would serve as the research site, so we set off through the jungle upstream to have a look. With each step in the forest, small brown frogs jumped out from under our feet. We had to be careful not to step on them. At the stream crossing (chosen with care so as to not disturb the bottom of the stream for our experiment) the pool had hundreds of small tadpoles swarming along the bottom.

I have spent quite a bit of time studying aquatic systems and the only time I have ever seen so many frogs and tadpoles at these densities was in the quaking bogs surrounding small lakes high in the Oregon Cascades in the 1980’s. These bogs form at the upstream end of lakes and have floating vegetation mats and deep water holes that the unwary will fall into. The conditions, once the snow melts, are perfect for breeding frogs, and they are everywhere there. My mind drifted back to Oregon, and then snapped into focus on the jungle frogs at hand.

Water in the stream gurgled between the rocks, rocks rounded by the many floods over the centuries rolling them along the stream channel and grinding them to smoothness. First they were eroded by the weather until were free from the volcanic hillsides above, then they fell and washed down the outer slopes of the crater, and eventually they would be ground by the energy of the water scraping them against other rocks to end up as grains of sand on the ocean beaches tens of miles away.

Occasionally parrots would make a racket in the distance, a toucan would fly high overhead, or a blue butterfly with a wingspread wider than my head (Morpho) would glide past. I found myself looking for monkeys and sloths, but found none.

From El Valle to Rio Maria

Having gotten settled into the hotel with plans made, lists created, and some materials packed and organized, the group piled back into the vehicles and headed into town for dinner. The small restaurant we went to on the main street was also a hotel that catered to young tourists. It was open to the front and to the side overlooking a lush garden. The lone server eventually showed up at our table (it was not exactly clear what took her so long as there was nobody else in the restaurant, but that is Panamanian time) and we ordered some drinks and dinner.

Panamanian food is unique; Americans might assume it is spicy, like Mexican food, but mostly it is not. As with all Central American food, rice and black beans are common. However, fried green plantains (patacones) are often served as a starch instead. Other common starches included potatoes and tortillas. The tortillas are corn patties that are substantially thicker than those common in Mexico. They are fried in oil and are very flavorful. There are a variety of meat dishes and beef is common. Chicken is served in several more diverse dishes. One of my favorites was chicken with garlic (pollo al ajillo). While most Panamanian food is not spicy, this dish is loaded with garlic, about a head of garlic per plate. Those who want chili head in their food can use the habanero pepper sauce that is regularly on the table. The food in the restaurant, while simple, was delicious.

After dinner we returned to the hotel and started going through lists of experimental equipment required for the next day. It took an hour or so to get ready and go over plans with Piet asking questions. We needed to charge up the batteries for field gear and make sure we did not forget anything because the 1.5 hour drive back to the hotel from the field site would preclude getting all our field work done if we had to return for additional equipment. After a rum nightcap, we headed to bed with plans to wake at sunrise.

It was an early start with a quick breakfast of fruit and cereal. Coffee drinkers had theirs, and I had a warm diet coke that I had picked up from the grocery store the day before, yum. We finally loaded the gear into the four wheel drive trucks and hit the road. The trucks are really well set up for the research. They are diesel, and have quite powerful engines, extended cabs, and take a lickin’ and keep on tickin’.

There was actually a road going up along the crater walls through that looked like cliffs from the hotel. The dirt road to the research site wound its way up through the inside of the crater walls and eventually crossed the lip of the crater; the entire road was extremely steep and rough.
As we worked our way up the steep valley leading out of the volcano it became evident that a number of people lived in the valley. A few miles up the road there was a small store and a school. A small soccer field clung to the edge of the hill. A couple times a day, a small bus came along. Most of the small farms up the side of the hill used foot or pack animals to carry materials in and out to the edge of the road, some all the way down to El Valle. As we wound our way up the side of the volcano the jungle became more predominant and the farms farther apart.

Eventually we reached the steepest hill on our trip. At this point the trucks had to be shifted into low 4-wheel drive, and we needed to get a running start at the hill. The trucks are old-style 4-wheel drive and we got out and locked the front hubs before starting. Some of the more nervous (experienced?) passengers got out and started walking up the worst of the hill on foot. This road went straight up the side of the mountain and had deep ruts from winter rains and other 4-wheelers. The vehicles bounced up and down and rocks shot out behind as the wheels spun. One of the drivers did not start fast enough and had to back all the way down and start again. If driving up such a steep hill was difficult, you can imagine the danger of backing down.
We finally got to the top of the hill and wound our way over the rim of the volcanic crater. When gaps in the jungle allowed, we could see all the way down to the coast, and other hills and mountains in the distance. The view was spectacular. The jungle here is very thick and lush. It is a rain forest that catches moisture from the clouds that roll in from the ocean, and the trees are covered with moss, lichens, and epiphytes including orchids. This dense green vegetation occasionally opened up to frame views of a thousand foot high pinnacle created by old cinder cones (Picachao Mountain) on the edges of the volcano. Near the top there were several hundred feet of sheer vertical cliff face of rock, where the volcanic deposits that formed the ancient eroding cone were exposed, otherwise the jungle clung to the cliffs and hills. Flocks of parrots flew across in the distance. A small lake was nestled into the bottom of the pinnacle, this lake had formed when a secondary explosion opened a crater that subsequently filled with water.

After working our way a few miles down the outside flank of the volcano we started to catch glimpses of the valley for the Rio Maria, our research stream. The stream originates high in the steep outer walls of the ancient volcanic crater, as the rivulets combine it forms a large valley that winds its way down the mountain across the coastal plains to the ocean, 20 miles or so away. We parked our trucks near the edge of the bridge and we got out to look at the stream. The sound of calling frogs met us immediately. There were two golden frogs on the stream bank across from where we parked, and we started taking some pictures, but we needed to get our first experiments started so we did not spend too much time looking around.

In the volcano

We pulled off the road at an overlook to take in the city of El Valle. The view was breathtaking. The town is nestled at the bottom of a huge volcanic crater with the rims of the old volcano rising circling above it. The rim of the volcano is so steep it forms almost vertical walls around ¾ of the city.

About a million years ago, the mountain that was El Valle volcano experienced a massive and cataclysmic explosion. The explosion left a 3½ mile wide crater and walls over 600 feet high. After the explosion the crater filled with water and contained a lake. The sediments and dead animals and plants in the lake waters settled over many years creating a flat bottom. Eventually a side of the crater washed out leaving the flat bottom of the lake that became a rich soil. This verdant land became the site of the town of El Valle and the cropland that surrounds the town. The steep walls of the crater are now draped with jungle so the area has the feel of a hidden tropical paradise, a Central American Shangri-La.

The high altitude leads to perpetual spring time. In the tropics, flowers are always blooming. It is a beautiful area and there is no doubt why people want to own houses on the slopes of the volcano and why many Panamanian tourists and international visitors vacation in El Valle.
Small houses and fields cling to the slopes of the steep walls of the volcano about 1/3 of the way up the sides. Eventually, the pitch gets so steep that the land cannot be lived on or worked and it gives way to jungle. When the slope is steep enough there are sheer rock faces that even the jungle cannot cling to.

The steepness is why there is still any wildness left in the area. Crops are scratched out of hillsides that would be considered un-farmable in the US because mechanized agriculture cannot be used, but the hills eventually are too steep for manual agriculture. The farms clinging to the hillsides reminded me of Switzerland where crops or grazing pastures are on slopes so steep a loss of footing could lead to a fatal tumble. It was obvious that the dirt itself was just clinging to the volcano sides from the numerous scars of landslides on the slopes around the valley.
The town looked very inviting because of the green productive fields and then the steep walls surrounding El Valle; we looked forward to getting down to our home base. Edgardo pointed out a large white hotel across the valley that was to be our headquarters for the next 9 days. We got back into the trucks and wound our way down the steep mountain road toward it.

When we drove up to the Hotel Campestre, it was clear that it had once been an opulent inn. The expansive grounds appeared well designed, with a circular fountain in front of a large central building. The hotel had a backdrop of a nearly vertical vine-draped wall of the volcano. Spreading to the side of a large main lobby and restaurant area, there were a couple of white two-story wings of the building housing 20 rooms each. In front of the hotel and a bit off to the side, we saw what was once a large swimming pool. Along one end of the pool there were smaller stepping-stone pools with fountains and waterfalls connecting each pool eventually cascading into the main swimming pool. Just past the pool was what appeared to be a caretakers quarters.

Upon closer inspection, the pool was filled with sediment, vegetation and insects. For biologists, the decay of the pool offered an opportunity, and while Matt and Edgardo checked us in, the rest of us tried to identify its inhabitants.

The most impressive animal in the pool was the large dragon fly larvae. These larvae are fearsome predators with a flip-spring jaw with a small hook on the end that extends in a millisecond to grab unsuspecting small aquatic insects and even fish. We also saw our first tadpoles here. There were, unfortunately, also many mosquito larvae, so the dragon fly larvae were not keeping up with their job, and I was wishing my DEET was not in my lost luggage.

The main entrance of the hotel had large wood timbers for support and overhead. We walked through the lobby to get our keys, and there was an aquarium with a bright yellow and dark brown splotched frog. This was the famous Panamanian golden frog (Atelopus zeteki), about 2-3 inches long. This poor fellow did not look well and Matt remarked that they probably purchased a new frog caught by locals from the plentiful supply in the nearby jungle every few weeks and didn’t worrying about feeding it.

The Panamanian golden frog is considered lucky. Legend has it that indigenous people in the region traveled to El Valle to catch the frogs. Some considered it a symbol of virility and prosperity. The frog adorns lottery tickets in Panama and the species is an icon in a land with many, many attractive species. This was one of the species that would disappear from the wild when the disease swept through the region.
We got our keys and I helped the others carry their gear to the rooms, and our equipment to the lab. Edgardo, his girlfriend Heidi Ross, Piet Verburg, and Scott Connelly, were living in the lab-house combination off the edge of the hotel that initially appeared to be caretakers housing. This house had been a duplex and each side had a large kitchen in front and several back bedrooms. One side had been left for housing and the other converted to use as a lab and storage area. The large front room on one side that had been converted into a laboratory was stacked with equipment and the small amount of table space was given over to sample processing and analysis.

As we approached the lab/ house, a small whitish dog came out to greet us. As with most Central American dogs, she was not well kept. She was also pregnant. Since she got food, she kept returning to visit us and bark at any strangers who happened by. She was a nice affectionate dog, but I was not sure that petting her was worth the risk of fleas. The dog, however, eventually won me over.

This is where I had the pleasure to first meet Heidi Ross, who was hired to work on the project as a technician. She initially came to Panama with the Peace Corps to El Cope. This was an earlier site for the frog project as well. El Cope is now little use for frog work because the disease already swept through there. She was interested in the frog work that was occurring before the disease came and volunteered to work on the project. Eventually, after her stint in the Peace Corps was done, she was hired and ended up getting together with Edgardo. Heidi wears her long curly hair in a ponytail and has nice green eyes. She was always around Edgardo, who is outgoing and gets most of the attention. Heidi is quiet but occasionally throws shocking off-color jokes into conversation. She is an excellent worker, never complains in harsh field conditions, and loves working with the frogs.

Piet Verburg was in the lab building and helped us get settled. Piet was the hired gun (we referred to him as Pistol Pete) on the project and had been living in the lab/bunkhouse building and starting to work on the research sites. Pete was on a postdoctoral appointment and did not have the numerous responsibilities that academic faculty members at universities have. Postdoctoral appointments are the positions many academic researchers must take before they get a permanent faculty position. These positions pay marginally better than graduate positions, but have no permanence. Often the postdocs do all the actual work on a project because they are trained and research is their only goal. It generally is a chance of a lifetime to totally immerse oneself into research.

Piet was born and raised in the Netherlands. He was hired for his top-notch research skills and expertise, and willingness to travel the world to do aquatic research. Piet did his doctoral research on Lake Tanganyika in Africa, a lake with hundreds of species of tropical fishes. He is a wiry athletic individual, with tight-cropped hair and wire-rimmed glasses. He moves perpetually and very extroverted. He will get up early and run 6 miles, do physical work all day, and then smoke and drink all night long. He persistently asks questions and loves to challenge the status quo and established scientific knowledge.

Scott Connelley was the third new person I met then. He is a graduate student who was studying the frogs for his dissertation. He is a short, dark-haired individual with a well trimmed beard and dark, quick bright eyes. He is energetic, quick witted and full of stories and dirty jokes to pass the time. Scott is also an excellent photographer who has been documenting the frogs in the wild before they go extinct. He regularly gives talks on loss of tropical diversity and is dedicated to conservation.

We set up our gear in the lab, and started to discuss our research plans. Piet asked questions and questions about our answers. We knew time was limited and needed to get to the stream, so we tried to be as direct in our answers as possible. We needed to get a fast start on the study the next morning to start our preliminary measurements. The experiments were going to be detailed and required substantial advance preperation. Some of the analyses we could do back in the US, but others required knowledge of the actual stream. So this time was also taken to get information from Scott, Piet, Heidi and Edgardo.

Understanding the effects of the frog losses required making sophisticated measurements of how the stream ecosystems work in the most fundamental sense. How nitrogen and carbon (fundamental chemicals found in all living organisms) flow through the plants and animals found in the streams is a essential characteristic of how these systems function. Our stable isotope method used forms of nitrogen and carbon that differ slightly from most of those elements found in our natural environment. We were going to take advantage of that fact to trace the fate of these compounds that are central to all biology as we know it, and specifically to the biology of the stream we were planning to characterize.

This type of research is an example of new, high-tech approaches that are available to environmental scientists. The nitrogen is a special form that has one more neutron in the nucleus, so it is a slight bit heavier than the more abundant form that has 7 neutrons and 7 protons (just 1/14th heavier). As far as the plants and animals are concerned, the tracer form of nitrogen with 8 neutrons is identical to the more abundant form with 7 neutrons, but science can tell the difference.

The samples that could have our tracer in them can be taken in the field and dried and ground up in the lab. A tiny bit, about the size of a head of a pin, is put into the mass spectrometer. The mass spectrometer burns up the sample and converts the nitrogen to single charged atoms. Inside the machine there is a series of magnets that accelerates the charged atoms into a stream of particles that are shot in a line through a tiny hole in another magnetic field. The field bends the charged atoms. Heavier atoms bend less than lighter ones, just like it is more difficult to make a tight turn with a large truck speeding around a corner than it is a sports car. The machine has a detector that can sense the two particle streams and indicate how much of the heavier atom there is. The numbers from the machine can be used to tell the relative amount of the tracer nitrogen there was in the sample.

We planned to add a pulse of these non-toxic tracer compounds and collect numerous samples during and after the pulse to characterize how the nitrogen was used in the environment. Samples were to be returned to the US where mass spectrometry could be used to analyze the samples and the results would eventually be used to calculate how quickly the materials moved into the plants, animals, microbes, and various chemical pools in the water.

The isotope and our time were both quite costly, so organization was absolutely necessary, and made more challenging by the makeshift conditions at the lab and even more demanding conditions in the field. We hoped it would not rain, and given it was the dry season, we probably had a 50% chance of dry weather. A flood could spell disaster for our project. The high walls of the volcano often caused the clouds to drop their moisture even in the “dry season”. Here, dry was relative. In addition, the steep walls lead to very rapid run off when it does rain, increasing the probability of flooding. The experiment was a one shot deal. We would not have time to redo the experiment if it was halted by a flood and it was unlikely that we would be able to get all the researchers back down to try do the experiment again. Plus, we did not know exactly when the frogs would start dying, and we needed measurements from before the die off.

From Panama City to El Valle

As we drove through downtown Panama City on our way to the mountains, Edgardo pointed out a barrio. The barrio was a jumble of unpainted high-rise apartments; unit was obviously inhabited by many people. The rooms all had either broken out windows or never had any installed and laundry was hung across most balconies along with lot of other unidentifiable stuff. The buildings were run down, dirty, had stained walls and crumbling. Edgardo told us that any US citizen who entered the barrio would probably not leave alive.

This was where Manuel Noriega had his headquarters; he had used it as a human shield. This decision, and the US invasion to unseat Noriega led to death and destruction. Noriega was the dictator of Panama from 1983 to 1989. He initially was on the payroll of the US Central Intelligence Agency because of his opposition of socialist governments in Central America and help controlling drug trafficking. For a while the CIA, turned a blind eye to his association with drug lords (Noriega was playing both sides of the fence here), weapons runners and the corruption in his government.

The 1989 election was rigged by Noriega, and former US president Jimmy Carter denounced the election as fraudulent. The potential loss of transport, including oil, through the Panama Canal was probably too great a financial risk to the US. US army personnel were harassed by the Panamanian military and one off duty US officer was shot. The situation escalated and in 1989 George H. W. Bush ordered the US to attack Panama to capture Noriega. Protection of the Panama Canal, protection of US citizens, restoration of democracy and human rights, and control of the drug trade were cited as the reasons for the invasion.

The US sent in over 50,000 troops and 300 aircraft. The attacks on the barrio caused as many as 5,000 Panamanian civilians to be killed; most died in a fire in the barrio around Noriega’s headquarters. There is still hatred there toward the US; emblematic of the darker side of the love-hate relationship Panama has with the US. The relationship has been long, with its origins in the US cutting the country in half by building the Panama Canal starting in the early 1900’s.

When I had visited Panama City in 1977, the canal was still under United States’ jurisdiction. Tensions existed then in the form of resentment toward the wealthy country that ran the canal in the midst of deep poverty. I will never forget the image of a suburban landscape, where the US military and canal zone personnel lived, surrounded by Panama City. The neighborhood was indistinguishable from the one I grew up in, except for the tropical flowers and palm trees in the gardens. Large mowed lawns being sprinkled, split-level houses, multi-car garages, and large cars were everywhere. Across a low wall and a four lane street was a slum with tar paper shacks and a burned-out apartment building without outer walls where many people lived. Large families lived in one room with no running water. The separation between rich and poor in the US was much better hidden.

There are large disparities between rich and poor in Latin America, but many of the rich build their houses behind walls. The walls often have broken glass embedded along the top or barbed wire to keep intruders out. The walls preclude a casual assessment of the amount of wealth from outside. The other places I had visited in the US, Canada, and Europe did not have the same degree of stark contrast clearly visible from the street between the poor and those with comfortable lives. The disparity was intense, and it highlighted a sharp inequality between my sheltered and privileged middleclass upbringing and the way much of the rest of the world lives.

In my 1977 trip, I felt the tension in the Canal Zone because the Panamanian military was a good bit more menacing than what I had experienced in Costa Rica. The civil service soldiers in Costa Rica were friendlier than the Denver police I had grown up with. The Panamanian military had machine guns slung over their shoulders, tightly cropped hair, and vacant looks in their eyes that I imagined were the looks of stone cold killers. I did not linger in front of them long enough to find out.

These thoughts ran through my mind as we passed the barrio where Noriega had his headquarters and made our way through Panama City west to El Valle. To go west from the city, you must cross the canal. We left the city via the Centennial Bridge over the Panama Canal. The bridge is almost a mile long and over 250 feet high. Large ocean-going ships pass under the bridge with no problem. As we crossed the bridge, I could see tanker ships lined up into the distance waiting to get into the canal. Another line of tankers chugged away into the Pacific Ocean having successfully crossed the isthmus from the Atlantic side. This is one of the great centers of commerce in the world.

The Panama Canal was and continues to be an enormous undertaking. Almost 28,000 workers died during its construction begun in the 1800s by the French and finally completed by the US. Now more than 200 million tons of cargo pass through it each year. The average ship pays $54,000 to go through the canal, resulting in almost $800 million in revenue a year. The US controlled the canal in Panama from when it was completed in 1914 until 2000.

The canal had its positive effects for the study of ecology. The Canal used dams to create large lakes in the center of Panama, and one of these lakes isolated Barro Colorado Island. Early in the history of the Panama Canal this island was protected as a biological reserve, one of the first in the New World.

Since then the Smithsonian has managed the site and it is one of the top tropical ecological research areas in the world. I visited this site in the 1970’s and this was one reason for my choice of career. The research station had a canopy crane so you could get up into the tops of the tropical trees and see the birds and butterflies fly through the canopy. This vantage point really makes it clear that tropical jungles have considerable habitat where people have difficulty reaching; the hundreds of feet of tree canopy is where most of the ecological action occurs. This also was the first place I saw lizards that could run across the surface of the water (JC lizards), live sloths, and many other tropical plants and animals. The long research record at the island makes it an extremely valuable ecological site, and with each year of data the Barro Colorado becomes more important.

The United States had sovereignty of this land that cleaved Panama; an obvious source of tensions between Panama and the US. Eventually the canal was returned to the Panamanians. Edgardo told me that many Panamanian citizens are not so certain that Panama should have taken the tremendous maintenance demand and responsibility for this vital passage from the US. However, the importance of the Panama canal may become a moot point with global warming; summer in North America now leads to an open Northwest Passage through the Arctic Ocean. In the future, with melting of the Arctic Ice cap, the passage could remain open for a large part of the year and take much of the traffic away from the canal. Given that Panamanians know that the US released much of the greenhouse gas that is causing this melting, they may have another reason to resent us. Still, the canal for now is central to the identity and economy of the country.

We made our way west on the Pan-American highway on a beautiful day, leaving Panama City behind, heading toward the high altitude jungles that were our destination. We had to drive west because although the Pan-American Highway is mostly a north/south highway, this part of the highway leads east/west. Because of the curve of Central America and where Panama is located, the country spreads from east to west.
The Pan-American Highway becomes less of a highway in the North American sense as you move away from Panama City. It is certainly not limited access. Pedestrians, bicycles, mules, wagons and other modes of transport move along edges in more rural areas. Small shops have their parking lots right next to the road, and access is not limited. This is a very busy central artery to the country full of trucks and cars.

After an hour or so of driving we stopped at to get fresh empanadas (hot cheese turnovers) and other refreshments. The cheese and empanada shop where we stopped smelled fantastic as any active bakery does. In most of the US, local bakeries are rare, and our lives are less enjoyable as a result. Furthermore, this was an excellent cheese shop, most places in
Central America carry only a few types of simple bland cheese, but this shop was replete with a variety of locally made cheeses. Having native Panamanians as members of our scientific team to educate us on regional delicacies definitely had its benefits.

Our next stop was to secure breakfast and lunch provisions from the grocery store for the next 9 days. This store was emblematic of the US influence on Panama. The landscaped parking lot and exterior of the store in a strip-mall setting would be indistinguishable from thousands of strip-malls in the US. The grocery did not have the variety of items available in North American supermarkets, but it was obviously modeled after the large grocery stores in the US. We purchased food that would keep for a few weeks in the tropical heat (tins of meat, sardines, clams), crackers, breakfast foods, snacks (chips and cookies), and beverages.

This trip marked the beginning of my appreciation for Latin American rums. We each purchased a couple of bottles of rum of different ages (5 to 25 years old). It turns out that Matt chose the store not only for the food, but probably more importantly, for the rum selection. There are many varieties available, and as I would find out, almost all but the very cheapest ones are excellent. Of course we also grabbed some cases of beer, soda, bottled water, and cans of Pina Guava (pineapple and guava juice) and limes (for breakfast or to mix with the rum in the evening). We crammed our provisions into the already full trucks and continued to head toward El Valle de Antón.

We first could see the location of El Valle as a distant peak rising above the hazy tropical plains of Panama. The peak is one of numerous volcanic cones that dot Central America and one of three large inactive volcanic cones in Panama. As we wound our way up the slopes the air became cooler, and our trip became more pleasant.

Small shacks and rudimentary concrete roadside dance halls blaring distorted Latin music and hip hop through large speakers lined the road side. This area at the bottom of the volcano was obviously agricultural and not wealthy. The vegetation was dry and sparse, but slowly began to switch to wetter, greener trees as we moved up in elevation. Simultaneously, the houses began to give way to more expensive haciendas.
This region has a history of one where wealthy Panamanians build second houses because the cool weather offers an escape from the heat of Panama City. Now it is a magnate for wealthy from all over the world including retiring US and European couples. As we found out, this movement toward large second homes is not always so good for the native flora and fauna. Eventually we made our way over the upper lip of the volcano and started our descent into the ancient crater, there we caught our first glance of El Valle.

Into Panama City

We loaded our gear into a couple of pick-up trucks and station wagons and left the airport. It is always strange driving into a new city, but doing so at night is more disorienting. Doing it jet-lagged, and in a different country adds to the surreal nature of arrival. We could see billboards advertising unfamiliar products next to those typical of the United States. It is difficult to avoid the economic tentacles of the United States; McDonalds, Kentucky Fried Chicken and Johnny Walker are everywhere.

The dark estuaries of the bay of Panama along the highway reeked of the sulfide and decay of marine mud. Most people do not like this odor, but it made me wonder what organisms were out there, in particular if there was any good algae. The tide was out, and across long black mud flats, the waters of the bay reflected the lights of large cargo ships. They line up to wait for the chance to go through the Panama Canal. The lights and skyscrapers of downtown Panama City were in front of us.

We entered the traffic of Panama City close to midnight. As in any large city, there was still considerable activity despite the late hour when we drove into town. The hubbub of crowded streets had a definite Central American flavor. There were cabs and busses painted with brightly colored murals of various religious and movie themes plying the streets. The cars and trucks were from all over the world. People had kept some very old vehicles alive and they belched exhaust as they noisily drove down the streets. We were entwined in hectic traffic; even though there were many older vehicles, there were some very expensive luxury cars as well. This provided the first taste of the juxtaposition of wealth and poverty of Central America.

Hotel Acapulco was tucked into a block of commerce and most businesses in the area had a parking lot surrounded by barbed wire. We pulled in, parked and carried our luggage (at least everybody else’s luggage) into our rooms, a guard watched over the lot and the front of the hotel. The gate was locked to protect the vehicles as we drug our luggage into the hotel.

What followed was the usual hour of haggling with the front desk. The uncertainty ensued because of lost reservations and changing “hotel policies”. Even with several of our party fluent in Spanish, the rooms took a long while to sort out. The extended discussion at the hotel desk always happens; nothing is simple in Central America. The rooms were not new, but they were not particularly dirty. Once we settled in, it was time to get something to eat. I will never understand why it makes me tired and hungry to sit around in airplanes, airports and taxis doing nothing all day.

Our hotel was across the street from a large casino and adjoined a 24-hour restaurant that catered to the late-night crowd associated with this active part of downtown. We took over several outside tables and ordered Cerveca Panamá (obviously a local beer). We ordered several types of ceviche (shrimp and corvina (a white sea bass) marinated with lime juice, cilantro, onions, and chilies). Ceviche is traditionally served with saltine crackers. We ordered streamed clams, some cooked octopus and more beer. Seafood is good in a port town, and we were not about to pass up the chance to have the real deal. Particularly me, coming from winter in a small town in the Midwest, appreciated it. Fresh clams are generally not on the menu back home.

Of particular interest to our group was a carousel inside a closed case that held pies. It was not that the pies looked so great, but the velocity at which the stacked lazy susan was rotating was astonishing. It must have been set on high, and we, being science nerds, referred to it as the “pie centrifuge”. At the time it seemed hilarious, but we were probably delirious from travel and beer. The food was excellent and it was entertaining to watch the street walkers and other characters of the city passing by.

After a bit we went up to our rooms, bleary eyed and travel worn. I brushed my teeth with my finger and water, splashed water on my face, hung my clothes to air out and got in bed. Matt had set his hair brush by the sink. This is a brush he has had since middle school and it is absolutely disgusting. The “brush” is decades old and just held together by the hair bonded to the remaining bristles. I am convinced he brings it when we room together just to bug me. The sound of the city below continued to seep in through the barred windows as I drifted to sleep with the gentle breeze and whirring sound of an overhead fan.

In the morning Matt and the others left to take care of business at the Smithsonian Tropical Research Institute, not far away in Panama City. Right after lunch we were to leave for El Valle, the jungle and the frogs, so I had till noon to get a few things. The normal travel precautions (no valuables left in the room, passport and extra cash in a hidden pocket) were taken before I left the room to replace essentials that were in my luggage.

I walked down the street toward a department store. Rapid fire Spanish surrounded me and I purchased an orange from a vendor for breakfast. Conveniently, the Panamanian dollar is tied to the US dollar and there is no need to exchange currency.

I found the department store and purchased the basics. On my way back I saw what turned out to be my favorite hand-painted city bus, it had a Harry Potter theme, but made Harry look deranged. Matt and the gang returned and we had a quick lunch in front of the pie centrifuge, loaded the vehicles and left for the El Valle.