Before we left we all took a last look at the site. I am usually sad when I leave a research site, but was more affected this time. I had become attached to the stream. The frogs were gone and this was a huge blow. The impending construction led me to believe that much of what made this stream special would be gone if I ever made it back again. We drove up the bumpy dirt road each lost in our own thoughts.
When we reached the point where the pavement began I got out to turn the locks off on the hubs from four wheel drive. I noticed the front tire was low so we started back to town to get it filled up. Just before we made it to the gas station where it could be repaired the tire went completely flat. When they realized our tire was flat, a couple of men immediately ran over to help. We all knew how to do it, but they were so enthusiastic that we allowed them to do most of the work. In the US people are generally a bit less willing to help a stranger. It is possible that they did so for hopes of a tip, but they did not seem to expect anything for their attention.
We finally got back to the hotel, and by 7:00 that evening had processed most of the samples and made some progress on analyzing the data collected from the electronic probes we had in the field over the last week. We cleaned out the back of the trucks and found out that Cathy had left several pairs of dirty socks. This was certainly expected.
Our first look at the data suggested that the reason for the dense algal growths in the stream really was the lack of frogs. The discharge of the stream and other basic properties were almost identical to what we had measured two years ago; temperature was within a half degree Celsius. The tropics are remarkably constant relative to many temperate habitats.
Piet had collected some samples for Emma that required centrifugation. We took some time off for dinner, and after we got back Piet worked on samples until about midnight. Heidi brought over a guitar for Alex and I played harmonica with him for awhile. We turned in relatively early because the next day we would leave for Panama City and we had a lot to get done before we could leave. Amanda would stay behind and continue sampling at the experiment site. I lay in bed contemplating the loss of the frogs and the construction on the site.
I was concerned about Amanda’s financial condition and left her some money. She had some problem with money being transferred into an account in the states, and had very little to live on for her next month in Panama. This was paying it forward in a way.
When I was a student traveling in Costa Rica, Dan Janzen was staying in the hotel we were using. Janzen is probably the best known living tropical ecologist in the world. He has dedicated his life to studying and conserving the tropics. He has since been elected a member of the US National Academy of Sciences and received the half million dollar McArthur Fellowship (the “Genius” award). He is one of my scientific heroes.
The hero bit was cemented given his response to an overheard phone conversation with my parents about wiring money to Guatemala. I was going there next by bus, and they had not received an earlier request from me to wire money to Costa Rica. When I got off the phone he asked me how much money I had. I told him I had $50, and he immediately gave me $100 more. He knew it possible to be refused entry into many Central American countries if you were not carrying enough money and I could be stranded at any of the four border crossings between Costa Rica and Guatemala. That was a good bit of money to give a stranger in 1977. I had to bother him for an address to send the money to repay him, and have been an admirer ever since. My admiration has only increased due to his untiring work to preserve tropical biodiversity, including helping establish the National parks of Costa Rica, and habitat restoration in that country.
Packing the next day took a long time. We not only had our own gear, but many boxes of scientific equipment that needed to be organized and packed and moved into our one remaining room. I took a brief walk up the stream that flows by the hotel and noticed a large raiding party of army ants on the trail. Thousands were spread out in one area, and columns of them were racing along a cleared trail across the forest floor. Many were carrying insect parts and others were carrying eggs and larvae.
I made the mistake of mentioning this to Alex when I returned and he grabbed his camera and ran out of the room. He returned later with a grin and a number of bites from the soldier army ants. Packing took all morning and took longer without Alex. We finally went to grab lunch with Heidi and Edgardo. After lunch, we threw our gear in the back of the truck and headed out of town. The remainder of the trip was unremarkable. This was good because riots were still occurring in Panama City. The only evidence we saw of them was a large line of army personnel with machine guns standing guard around a building as we drove to the airport at 6:00 am. Evidently the rioters kept more civilized hours.On the plane I reflected on how out of kilter my second trip to Panama seemed relative to my first. Foremost, was the disappearance of the frogs. Second, was the development entering the valley of Rio Maria. Finally, all the little things, getting sick, the stolen computer, the flat tire, the malfunctioning gear, Matt being worried about his animals, and concern over the riots in Panama City, that had happened this time but not the last .
Monday, March 29, 2010
Monday, March 22, 2010
The end of the experiment
We returned to the hotel and analyzed our samples for nitrogen. We were done around 4:00 in the afternoon and decided to drive down to the beach. Alex opted to stay behind. He needed to teach a lecture to his class the morning after he got home. His notes for it were on the disappeared laptop. He borrowed one of our computers, planted himself with two pillows propped behind his back on his bed and got to work re-writing his lecture.
Not 15 minutes after we left, he heard a sound at the window. One of the maintenance men from the hotel was climbing up a stepladder to the window. Looking quite startled to see Alex in his room, he continued climbing and did something right above the window.
He left rather quickly and a short time later another hotel worker came and took the ladder. Alex went out to look at what the maintenance man was doing but saw nothing other than a concrete sill and the top of the window. Nothing looked changed or worked on; there was essentially nothing to work on there.
It all seemed very suspicious given that Alex’s laptop had disappeared from two rooms down, and the thief hand entered through the same window. We decided Edgardo was probably correct about who had taken the computer earlier, but had no way to do anything about it.
The next day was our last field day and we needed to collect samples of all the organisms in the stream so that we could determine where the nitrogen tracer had ended up. We collected algae from rocks, rotting leaves (filled with fungi and bacteria), and fine sediments both at the water surface and from the stream bottom. These are the primary food sources for the few remaining tadpoles, and many of the invertebrate larvae, freshwater crabs and few freshwater shrimp in the stream.
The other animals still in the stream are predators, such as the large (half inch long) vicious dragonfly larvae with extendable jaws that flip out and jab prey, and the dark brown hellgrammites as long a pinky finger with massive pinching jaws. A little caution is necessary with the hellgrammites because their jaws can draw blood. Amanda collected the animals because she had the collection permits from the Panamanian government, such permits are not necessary for leaves, sediment, and algae.
We pulled all our electronic probes out of the stream and attempted to download the data. I went to get the light meters from a clearing on the hill and walked down the new road carved over the last few days into the hillside above our research site. It went to an area along the hill about half way up our experimental reach.
The new road had broad areas of dirt that had been exposed. At the top of the cut, it was easy to see that the jungle soil has a thin black layer that sits on a very poor mineral soil beneath. In the US, this type of construction would require that materials be placed over the open sediments to stop erosion from allowing the sediments to pollute the nearby streams. No such requirements are in place in Panama, or if they were, they were not being enforced. Luckily, sediments from the construction had a hundreds of feet to go through the forest and densely vegetated side channels before reaching our stream. The rapid regrowth might cover the open sediments before the rainy season came and erosion began in earnest.
The sediments would not influence our results from this week. However, once all the houses were built in the marked lots, it looked very likely to me that the portion of Rio Maria we were studying would become severely degraded. This was sad, but being a researcher, thoughts of coming back to document the effects also occurred to me. Just recently ecologists have started studying urban and suburban streams in the US, but little work has been done elsewhere in the world. With our extensive background data, we would be able to detect any changes that occurred in the stream. This seems to be the way than many scientists deal with bad things, they study them.
Upon my return to the stream with the light meters, I learned that one of the instruments had malfunctioned, but we had a duplicate, so this was not a problem. The pump that had been used to release the tracer was turned off. As we carried the last of the sampling gear and electronics it started pouring rain. The group joke was “Dry season? This is a heck of a way to run a rain forest”. Not a great joke, but it had rained every day and this was an unusually wet dry season .
Not 15 minutes after we left, he heard a sound at the window. One of the maintenance men from the hotel was climbing up a stepladder to the window. Looking quite startled to see Alex in his room, he continued climbing and did something right above the window.
He left rather quickly and a short time later another hotel worker came and took the ladder. Alex went out to look at what the maintenance man was doing but saw nothing other than a concrete sill and the top of the window. Nothing looked changed or worked on; there was essentially nothing to work on there.
It all seemed very suspicious given that Alex’s laptop had disappeared from two rooms down, and the thief hand entered through the same window. We decided Edgardo was probably correct about who had taken the computer earlier, but had no way to do anything about it.
The next day was our last field day and we needed to collect samples of all the organisms in the stream so that we could determine where the nitrogen tracer had ended up. We collected algae from rocks, rotting leaves (filled with fungi and bacteria), and fine sediments both at the water surface and from the stream bottom. These are the primary food sources for the few remaining tadpoles, and many of the invertebrate larvae, freshwater crabs and few freshwater shrimp in the stream.
The other animals still in the stream are predators, such as the large (half inch long) vicious dragonfly larvae with extendable jaws that flip out and jab prey, and the dark brown hellgrammites as long a pinky finger with massive pinching jaws. A little caution is necessary with the hellgrammites because their jaws can draw blood. Amanda collected the animals because she had the collection permits from the Panamanian government, such permits are not necessary for leaves, sediment, and algae.
We pulled all our electronic probes out of the stream and attempted to download the data. I went to get the light meters from a clearing on the hill and walked down the new road carved over the last few days into the hillside above our research site. It went to an area along the hill about half way up our experimental reach.
The new road had broad areas of dirt that had been exposed. At the top of the cut, it was easy to see that the jungle soil has a thin black layer that sits on a very poor mineral soil beneath. In the US, this type of construction would require that materials be placed over the open sediments to stop erosion from allowing the sediments to pollute the nearby streams. No such requirements are in place in Panama, or if they were, they were not being enforced. Luckily, sediments from the construction had a hundreds of feet to go through the forest and densely vegetated side channels before reaching our stream. The rapid regrowth might cover the open sediments before the rainy season came and erosion began in earnest.
The sediments would not influence our results from this week. However, once all the houses were built in the marked lots, it looked very likely to me that the portion of Rio Maria we were studying would become severely degraded. This was sad, but being a researcher, thoughts of coming back to document the effects also occurred to me. Just recently ecologists have started studying urban and suburban streams in the US, but little work has been done elsewhere in the world. With our extensive background data, we would be able to detect any changes that occurred in the stream. This seems to be the way than many scientists deal with bad things, they study them.
Upon my return to the stream with the light meters, I learned that one of the instruments had malfunctioned, but we had a duplicate, so this was not a problem. The pump that had been used to release the tracer was turned off. As we carried the last of the sampling gear and electronics it started pouring rain. The group joke was “Dry season? This is a heck of a way to run a rain forest”. Not a great joke, but it had rained every day and this was an unusually wet dry season .
Wednesday, March 17, 2010
Truck swap and the cloud forest
Later that evening we continued processing samples and preparing containers for the next day of sampling. Procedures for dealing with samples mostly consisted of filtering, but a lot of care was required not to cross-contaminate samples. Samples were dried if possible and frozen if not. Frozen samples were difficult to transport back to the US, but it could be done with a cooler and the maximum of 4 pounds of dry ice that was allowed to be checked in luggage. It makes sense not to allow more, the dry ice can release a large amount of carbon dioxide, and if this occurs in a confined area could possibly cause suffocation.
The next day the four early departures left for Panama City and the rest of us went to the field. After a typical day at Rio Maria, we finished our sampling and drove back. Just as we got to the hotel, Amanda’s phone began to ring. When she dug it out, we found out that Matt had taken the wrong truck to Panama City, and the people at the Smithsonian Research Institute were insisting that the correct truck be returned. This was frustrating because the trucks were the same make and the same age. They insisted on the one we had so Amanda and Alex had to drive to Panama City to exchange them. They drove down and back (4 hours) while Bob and I worked on the data we had collected. They finally retuned at 1:30 am. At least they got a good dinner at our favorite Peruvian seafood restaurant in the city while they were there.
The next morning as we traveled to the field site, I started to feel the pounding of the road. It was not as bad as during our previous trip because about half of the road had been paved since then. Still, the two steepest hills were rough clay roads with ruts, and we all mentioned how we were beginning to feel it. It is amazing that there are truck and bus drivers that take the lower half of this route all day every day.
The day was a short sampling and experiment day. We started experiments and then waited three hours to read the results. Alex had broken the edge off a termite nest attached to a tree and we watched them repair the damage as Alex narrated with infectious and perhaps slightly deranged entomological zeal.
When their nest is damaged, termite soldiers swarm out to protect it. This species of termite had soldiers with nozzle heads. The heads release a sticky excretion that clogs up any predator. After the initial disruption, the colony settled down and the workers started moving to the edge of the damage and placing bits of masticated wood or soil and then turning around and cementing them in with secretions from their abdomens. Within a day the edge of the nest was sealed off.
Termite nests are most commonly preyed upon by raiding ants. The first defense is a strong wall on the nest, the second the soldiers gumming up the ants with their adhesive. The social insects in the jungle are either constantly at war with others, or under the threat of pirate-like attackers that literally are out to eat and or enslave their prey.
While termites are a nuisance to homeowners because they eat wood, they are a vital part of tropical ecology. They break down dead wood and release locked up nutrients much more rapidly than would occur otherwise. Termites have specialized microbial communities in their guts that break down cellulose and make the carbon available to the termite. Fallen wood does not last very long on a jungle forest floor in large part because of termites and the fact that their activities increase rates of bacterial and fungal breakdown of wood in this warm moist habitat.
Interestingly, termites are one of the larger sources of methane in our atmosphere. The bacteria in their gut release the gas into the atmosphere. This is an important greenhouse gas that contributes to global warming. The first estimates of release rates were too high because they did not account for the presence of other bacteria in the walls of the mound that eat much of the released methane before it escapes into the atmosphere.
On our trip back from Rio Maria to El Valle that afternoon we stopped at the highest point in the road and hiked up a trail to an overlook. Hiking the trail was very strenuous; it was only a half mile, but it was very steep. We had all our most valuable equipment (computers and cameras) with us because of the lack of security at the hotel, and the inability to properly secure items in the trucks. The hike was made a bit more difficult with the packs we needed to carry. Impressively, the trail had many concrete steps. The concrete had to be packed in on the narrow trail. The last bit of the trail to the top was wooden stairs, and they were steep and slippery.
At the top of the trail was a true cloud forest with what appeared to be primary growth trees. Clouds poured over the high mountains and the ridge we were on. A continuous mist permeated the air. The forest was dripping wet and mosses grew on every surface that did not have higher plants on it. The trees were not extraordinarily tall, presumably because of the fierce winds that pummeled the ridge during the many tropical storms in the area. Each tree was covered with hundreds of species of epiphytic plants. Their sides were enveloped with vines, and their branches supported numerous bromeliads and orchids.
The flowers were sturdy and apparently pollinated by bees or hummingbirds. In colder areas, smaller pollinating insects cannot move well enough to fly. Bees can thermoregulate to some degree by moving their wings to increase their body temperature. Their relatively large bodies do not lose this heat as quickly as those of their smaller relatives. Hummingbirds, of course, are warm blooded. To some extent the large bees, and certainly the hummingbirds can fly up the steep hills from the warmer lower elevations in a matter of minutes.
The view from the top was spectacular, as clouds moved rapidly across the mountains and others opened temporarily nearby allowing us glimpses of pieces all around us. Immediately across the nearest valley, the large pinnacle of rock (the remains of the core of an old volcano) had a lake right at its base. Called a Marr lake, it had formed when a steam explosion underground made a perfectly round hole. Behind us, El Valle nestled in its 6 mile wide crater, was formed in a similar (albeit substantially more catastrophic and impressive) fashion. Thirty miles away, the ocean was visible and the steep gradient of moisture between it and us was apparent.
The cloud forest we were in gave way to a less stunted forest first, then eventually to a dry seasonal forest. Since this was the “dry” season, many trees on the lower slopes of the mountain had dropped their leaves and were now brown. They would grow new ones once the wet season started again. But for now, the transition from green, to brown, to the blue ocean was brilliant.
We could see the development encroaching on the entire watershed of El Valle. Tropical forest was being bulldozed to make half million dollar homes. The cul-de-sacs were evident from miles away. These cul-de-sacs looked just like those in any new subdivision in suburban US.
The next day the four early departures left for Panama City and the rest of us went to the field. After a typical day at Rio Maria, we finished our sampling and drove back. Just as we got to the hotel, Amanda’s phone began to ring. When she dug it out, we found out that Matt had taken the wrong truck to Panama City, and the people at the Smithsonian Research Institute were insisting that the correct truck be returned. This was frustrating because the trucks were the same make and the same age. They insisted on the one we had so Amanda and Alex had to drive to Panama City to exchange them. They drove down and back (4 hours) while Bob and I worked on the data we had collected. They finally retuned at 1:30 am. At least they got a good dinner at our favorite Peruvian seafood restaurant in the city while they were there.
The next morning as we traveled to the field site, I started to feel the pounding of the road. It was not as bad as during our previous trip because about half of the road had been paved since then. Still, the two steepest hills were rough clay roads with ruts, and we all mentioned how we were beginning to feel it. It is amazing that there are truck and bus drivers that take the lower half of this route all day every day.
The day was a short sampling and experiment day. We started experiments and then waited three hours to read the results. Alex had broken the edge off a termite nest attached to a tree and we watched them repair the damage as Alex narrated with infectious and perhaps slightly deranged entomological zeal.
When their nest is damaged, termite soldiers swarm out to protect it. This species of termite had soldiers with nozzle heads. The heads release a sticky excretion that clogs up any predator. After the initial disruption, the colony settled down and the workers started moving to the edge of the damage and placing bits of masticated wood or soil and then turning around and cementing them in with secretions from their abdomens. Within a day the edge of the nest was sealed off.
Termite nests are most commonly preyed upon by raiding ants. The first defense is a strong wall on the nest, the second the soldiers gumming up the ants with their adhesive. The social insects in the jungle are either constantly at war with others, or under the threat of pirate-like attackers that literally are out to eat and or enslave their prey.
While termites are a nuisance to homeowners because they eat wood, they are a vital part of tropical ecology. They break down dead wood and release locked up nutrients much more rapidly than would occur otherwise. Termites have specialized microbial communities in their guts that break down cellulose and make the carbon available to the termite. Fallen wood does not last very long on a jungle forest floor in large part because of termites and the fact that their activities increase rates of bacterial and fungal breakdown of wood in this warm moist habitat.
Interestingly, termites are one of the larger sources of methane in our atmosphere. The bacteria in their gut release the gas into the atmosphere. This is an important greenhouse gas that contributes to global warming. The first estimates of release rates were too high because they did not account for the presence of other bacteria in the walls of the mound that eat much of the released methane before it escapes into the atmosphere.
On our trip back from Rio Maria to El Valle that afternoon we stopped at the highest point in the road and hiked up a trail to an overlook. Hiking the trail was very strenuous; it was only a half mile, but it was very steep. We had all our most valuable equipment (computers and cameras) with us because of the lack of security at the hotel, and the inability to properly secure items in the trucks. The hike was made a bit more difficult with the packs we needed to carry. Impressively, the trail had many concrete steps. The concrete had to be packed in on the narrow trail. The last bit of the trail to the top was wooden stairs, and they were steep and slippery.
At the top of the trail was a true cloud forest with what appeared to be primary growth trees. Clouds poured over the high mountains and the ridge we were on. A continuous mist permeated the air. The forest was dripping wet and mosses grew on every surface that did not have higher plants on it. The trees were not extraordinarily tall, presumably because of the fierce winds that pummeled the ridge during the many tropical storms in the area. Each tree was covered with hundreds of species of epiphytic plants. Their sides were enveloped with vines, and their branches supported numerous bromeliads and orchids.
The flowers were sturdy and apparently pollinated by bees or hummingbirds. In colder areas, smaller pollinating insects cannot move well enough to fly. Bees can thermoregulate to some degree by moving their wings to increase their body temperature. Their relatively large bodies do not lose this heat as quickly as those of their smaller relatives. Hummingbirds, of course, are warm blooded. To some extent the large bees, and certainly the hummingbirds can fly up the steep hills from the warmer lower elevations in a matter of minutes.
The view from the top was spectacular, as clouds moved rapidly across the mountains and others opened temporarily nearby allowing us glimpses of pieces all around us. Immediately across the nearest valley, the large pinnacle of rock (the remains of the core of an old volcano) had a lake right at its base. Called a Marr lake, it had formed when a steam explosion underground made a perfectly round hole. Behind us, El Valle nestled in its 6 mile wide crater, was formed in a similar (albeit substantially more catastrophic and impressive) fashion. Thirty miles away, the ocean was visible and the steep gradient of moisture between it and us was apparent.
The cloud forest we were in gave way to a less stunted forest first, then eventually to a dry seasonal forest. Since this was the “dry” season, many trees on the lower slopes of the mountain had dropped their leaves and were now brown. They would grow new ones once the wet season started again. But for now, the transition from green, to brown, to the blue ocean was brilliant.
We could see the development encroaching on the entire watershed of El Valle. Tropical forest was being bulldozed to make half million dollar homes. The cul-de-sacs were evident from miles away. These cul-de-sacs looked just like those in any new subdivision in suburban US.
Monday, March 8, 2010
The stolen computer
Other than the fact that the frogs were gone, the trip was going well. However, the first signs of something less than a smooth trip came up that night. I started getting sick with both a cold and a case of Montezuma’s revenge (or, as referred to in Panama, Noriega’s revenge). Matt got word from home that a large ice storm had taken the power out at his house.
His family was safe and they had a fireplace, but it was not enough to keep the over one hundred snakes, lizards, frogs, and tortoises warm. Matt had a large collection, and if the power was out for a sustained period of time many of these animals could be lost. Matt spent a lot of time on the phone with his wife planning how to protect the animals. The temperate ones would be ok if it did not freeze so they were moved into the basement. The tropical species could die if they even got cold, so they were moved as close to the fireplace as possible. Matt’s wife is a good sport, but she no doubt did not want to deal with being stuck at home in a massive ice storm with no power. Matt felt guilty and worried.
The next morning things got a bit better when Matt found out that power had been restored at home, and we once again went up to the stream to do research. We needed to collect our electronic sensor data. When Alex went to do that we found that the commands to start the electronics had been entered incorrectly and we had no data from the previous collection. Fortunately, we had several more days to collect data so we proceeded with experiments to find out how the invertebrate insect larvae, fish, and crabs would respond to the lack of tadpoles competing for the food that they also ate.
That evening we walked to a nice new restaurant nearby and had a fantastic dinner. While wandering home we got a bit lost. We were in a good mood when we got back to the hotel and planned to chat over drinks. Then Alex discovered that his laptop computer was not in his room, and suddenly things did not look so good. His first concern was not the value of the computer, but what data were on it that had not been backed up. Fortunately, all the data from Panama were backed up, and the rest of Alex’s possessions (particularly his passport) and our lab gear were still there.
Unfortunately, Alex had just returned from a winter sampling trip on the North Slope of Alaska near Prudhoe Bay, and all his photographs from that trip were lost. Photos from Rio Maria were also gone, but they could be re-taken.
The police were called and we ascertained that the thief had entered through a window. Edgardo suspected that someone from the hotel was responsible, but we were not so certain.
The only amusing moment of the night was when Matt went out and around to the window to see how easy it was to reach into where the laptop had been. He had his head and body in the window and was reaching down toward where the computer had been when the police, who had just arrived, walked into the room. Matt turned very red and the police eventually understood what was going on, but it looked a bit suspicious at first. We had returned at 10:00 and the police were there for 3 hours before they left.
The next morning we woke up and realized we needed to reassess our approach to security and decide if we wanted to stay in the hotel. We could not afford the time it would take to move, so decided to stay put. We fashioned bars to put in the windows and figured out hiding places for our valuables. Most valuables we either needed to take with us or leave somebody behind to guard the rooms. This was not too difficult that day because we had a number of samples that needed to be processed in our laboratory/ hotel rooms, so some of the group stayed. Alex went with Edgardo to the town an hour away where the police report needed to be filed with the detectives. We knew that this was a lost cause, but Edgardo wanted to document the string of problems that had occurred at the hotel.
The research project, at least, was only coming up against minor hitches and seemed to be going well. We returned from our field day and went to dinner as a group. While we were out we heard that police had shot a labor protester in Colon, the Panamanian city on the north (Caribbean) side of the Panama Canal. The riots from Colon had spread to Panama City. The police had arrested 500 people and Panama City was being shut down. Matt, Karen, Kathy and Emma needed to leave soon and we started feeling concerned about getting out smoothly and safely. El Valle was safe, but we needed to travel through Panama City to get home.
His family was safe and they had a fireplace, but it was not enough to keep the over one hundred snakes, lizards, frogs, and tortoises warm. Matt had a large collection, and if the power was out for a sustained period of time many of these animals could be lost. Matt spent a lot of time on the phone with his wife planning how to protect the animals. The temperate ones would be ok if it did not freeze so they were moved into the basement. The tropical species could die if they even got cold, so they were moved as close to the fireplace as possible. Matt’s wife is a good sport, but she no doubt did not want to deal with being stuck at home in a massive ice storm with no power. Matt felt guilty and worried.
The next morning things got a bit better when Matt found out that power had been restored at home, and we once again went up to the stream to do research. We needed to collect our electronic sensor data. When Alex went to do that we found that the commands to start the electronics had been entered incorrectly and we had no data from the previous collection. Fortunately, we had several more days to collect data so we proceeded with experiments to find out how the invertebrate insect larvae, fish, and crabs would respond to the lack of tadpoles competing for the food that they also ate.
That evening we walked to a nice new restaurant nearby and had a fantastic dinner. While wandering home we got a bit lost. We were in a good mood when we got back to the hotel and planned to chat over drinks. Then Alex discovered that his laptop computer was not in his room, and suddenly things did not look so good. His first concern was not the value of the computer, but what data were on it that had not been backed up. Fortunately, all the data from Panama were backed up, and the rest of Alex’s possessions (particularly his passport) and our lab gear were still there.
Unfortunately, Alex had just returned from a winter sampling trip on the North Slope of Alaska near Prudhoe Bay, and all his photographs from that trip were lost. Photos from Rio Maria were also gone, but they could be re-taken.
The police were called and we ascertained that the thief had entered through a window. Edgardo suspected that someone from the hotel was responsible, but we were not so certain.
The only amusing moment of the night was when Matt went out and around to the window to see how easy it was to reach into where the laptop had been. He had his head and body in the window and was reaching down toward where the computer had been when the police, who had just arrived, walked into the room. Matt turned very red and the police eventually understood what was going on, but it looked a bit suspicious at first. We had returned at 10:00 and the police were there for 3 hours before they left.
The next morning we woke up and realized we needed to reassess our approach to security and decide if we wanted to stay in the hotel. We could not afford the time it would take to move, so decided to stay put. We fashioned bars to put in the windows and figured out hiding places for our valuables. Most valuables we either needed to take with us or leave somebody behind to guard the rooms. This was not too difficult that day because we had a number of samples that needed to be processed in our laboratory/ hotel rooms, so some of the group stayed. Alex went with Edgardo to the town an hour away where the police report needed to be filed with the detectives. We knew that this was a lost cause, but Edgardo wanted to document the string of problems that had occurred at the hotel.
The research project, at least, was only coming up against minor hitches and seemed to be going well. We returned from our field day and went to dinner as a group. While we were out we heard that police had shot a labor protester in Colon, the Panamanian city on the north (Caribbean) side of the Panama Canal. The riots from Colon had spread to Panama City. The police had arrested 500 people and Panama City was being shut down. Matt, Karen, Kathy and Emma needed to leave soon and we started feeling concerned about getting out smoothly and safely. El Valle was safe, but we needed to travel through Panama City to get home.
Monday, March 1, 2010
The Disease
That evening we had several discussions about the disease and the decline and loss of frog species. This was fascinating to hear because Karen is a world expert on it and Heidi and Egardo are local experts on methods of culturing and modes of disease. Both have dedicated their professional lives to different aspects of the disease.
Not much is known about how the disease propagates and why it kills some species and not others. The thought is that the fungus is centered on the streams and when adult frogs come in contact with the stream or infected animals they contract the disease. Some tadpoles can withstand the disease, but others loose their mouthparts and become unable to feed. The mode of disease transmission explains why there were still some tadpoles in Rio Maria. Adult frogs can live for many years and do not necessarily breed every year. If a frog stays out of the stream and has no contact with infected individuals, it may live through the first wave of disease. Eventually, however, the frog mates or contacts another frog with the disease and contracts the disease.
The frog-to-frog transmission also makes sense with respect to the rate of spread of the disease. The disease spreads through the lowland tropics without killing most species. Apparently at the higher temperatures, the fungus is less deadly to amphibians found Central America. Models of the rate of the disease spread based on animal-to-anima contact are consistent with the observed rates of spread. The wave-like movement of the disease front is also consistent with an amphibian contact route. If the disease was spread by wind or carried around by birds or flowing water, the rate of spread and geographic pattern of disease spread would be very different.
Karen also mentioned recent research indicating that the cause of the spread of the disease is not well known. Recent results suggest that the African Clawed Frogs are not the source of the disease because genetic analysis indicates the strain of fungus originated in New England.
However, the disease was reported in samples of Clawed Frogs taken in Africa as early as 1938, the approximate time when international trade of the species began. The presence of the disease was determined in museum specimens. Nobody knew about this disease in the 1930’s when the sample was collected. However, modern techniques can isolate DNA from preserved samples, amplify it with the polymerase chain reaction method, and analyze the sample for genes that are only found in the chytrid fungus that causes the disease. This is the same procedure used to exonerate criminals in rape or murder cases that are many years old; the biological samples from the crime are analyzed for the DNA left in them. Biologists trying to reconstruct genetics of the past now analyze tiny bits of samples preserved in museums.
The difficulty with pinning down an exact source of the frog disease is that many species of frogs are moved around the world all the time, and other species can carry the disease as well. Indiscriminate movement of species can have very negative unforeseen consequences. The end result is the same regardless of exactly where the disease came from; the disease is in Central America and causing numerous extinctions. The moral for the future is that we should be very careful about moving biological materials around the globe.
Regardless of the exact original cause, the disease has spread around the world and is endangering species in many places. The disease was first recognized in Australia, where it has caused many frog deaths and spread to New Zealand and Tasmania. Only a few realized the problems the disease caused in the US because it spread in the mid 1900’s when people were unaware of the issues or and frog populations were not carefully documented. Now people are becoming aware of the disease in the US. For example, it is harming salamanders in the Southeastern part of the country.
With so many people and animals moving around, the spread of the disease is inexorable. In South America, separate infections were initiated in several distinct areas and now it has spread through much of the northern part of the continent.
Not much is known about how the disease propagates and why it kills some species and not others. The thought is that the fungus is centered on the streams and when adult frogs come in contact with the stream or infected animals they contract the disease. Some tadpoles can withstand the disease, but others loose their mouthparts and become unable to feed. The mode of disease transmission explains why there were still some tadpoles in Rio Maria. Adult frogs can live for many years and do not necessarily breed every year. If a frog stays out of the stream and has no contact with infected individuals, it may live through the first wave of disease. Eventually, however, the frog mates or contacts another frog with the disease and contracts the disease.
The frog-to-frog transmission also makes sense with respect to the rate of spread of the disease. The disease spreads through the lowland tropics without killing most species. Apparently at the higher temperatures, the fungus is less deadly to amphibians found Central America. Models of the rate of the disease spread based on animal-to-anima contact are consistent with the observed rates of spread. The wave-like movement of the disease front is also consistent with an amphibian contact route. If the disease was spread by wind or carried around by birds or flowing water, the rate of spread and geographic pattern of disease spread would be very different.
Karen also mentioned recent research indicating that the cause of the spread of the disease is not well known. Recent results suggest that the African Clawed Frogs are not the source of the disease because genetic analysis indicates the strain of fungus originated in New England.
However, the disease was reported in samples of Clawed Frogs taken in Africa as early as 1938, the approximate time when international trade of the species began. The presence of the disease was determined in museum specimens. Nobody knew about this disease in the 1930’s when the sample was collected. However, modern techniques can isolate DNA from preserved samples, amplify it with the polymerase chain reaction method, and analyze the sample for genes that are only found in the chytrid fungus that causes the disease. This is the same procedure used to exonerate criminals in rape or murder cases that are many years old; the biological samples from the crime are analyzed for the DNA left in them. Biologists trying to reconstruct genetics of the past now analyze tiny bits of samples preserved in museums.
The difficulty with pinning down an exact source of the frog disease is that many species of frogs are moved around the world all the time, and other species can carry the disease as well. Indiscriminate movement of species can have very negative unforeseen consequences. The end result is the same regardless of exactly where the disease came from; the disease is in Central America and causing numerous extinctions. The moral for the future is that we should be very careful about moving biological materials around the globe.
Regardless of the exact original cause, the disease has spread around the world and is endangering species in many places. The disease was first recognized in Australia, where it has caused many frog deaths and spread to New Zealand and Tasmania. Only a few realized the problems the disease caused in the US because it spread in the mid 1900’s when people were unaware of the issues or and frog populations were not carefully documented. Now people are becoming aware of the disease in the US. For example, it is harming salamanders in the Southeastern part of the country.
With so many people and animals moving around, the spread of the disease is inexorable. In South America, separate infections were initiated in several distinct areas and now it has spread through much of the northern part of the continent.
Subscribe to:
Posts (Atom)
